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Stainless steel is the name given to a group of corrosion resistant and high temperature steels. Their remarkable resistance to corrosion is due to a chromium-rich oxide film which forms on the surface. When ordinary carbon steel is exposed to rain water, for example, it corrodes forming a brown iron oxide, commonly called rust, on the surface. This is not protective and eventually the entire piece of steel will corrode and be converted to rust. But when enough chromium (more than about 10%) is added to ordinary steel, the oxide on the surface is transformed – it is very thin, virtually invisible and protective in a wide range of corrosive media. This is what we call stainless steel and there are several different types, and many different grades. Types of Stainless Steel The basic composition of stainless steel is iron (Fe) and chromium (Cr). This is the simplest form of stainless steel, with this family known as the ferritic stainless steels because their crystal structure is called ferrite. (This is also the structure of mild steel.) The ferritic stainless steels are magnetic like ordinary steel. A commonly used grade is Type 430 (S43000) which is used for automotive trim and inside dishwashers and clothes dryers. They are often the least expensive stainless steels but can be more difficult to form and weld. If we wish to make carbon steel strong and hard, such as for a drive shaft or wear plate, we might increase the carbon content, and then heat treat the steel by quenching and tempering it. We can do the same with stainless steel – if we increase the carbon content of ferritic stainless steels we produce the family of martensitic stainless steels, used for items such as knives, razor blades and corrosion resistant bearings. Martensitic grades are strong and hard, but are brittle and difficult to form and weld. Type 420 (S42000) is a typical example. Like ferritic stainless steels, martensitic stainless steels are magnetic. The majority of stainless steels contain nickel (Ni), which is added for a number of reasons but particularly to change the crystal structure from ferrite to austenite. Austenitic stainless steels are ductile, tough and, most importantly, easy to form and weld. These steels are not magnetic in the annealed condition. The most common example is Type 304 (S30400) or “18/8” – the most widely used stainless steel in the world. The lower carbon version, Type 304L (S30403) is always preferred in more corrosive environments where welding is involved. There are numerous applications for this grade, ranging from domestic kitchen sinks and building facades to commercial food processing equipment and chemical plant piping. Molybdenum (Mo) is added to some stainless steels to increase their corrosion resistance, particularly in marine and acidic environments. It increases an alloy’s pitting and crevice corrosion resistance. These corrosion forms are caused by the common and highly aggressive chloride ion (Cl¯), which is present in salts, such as sea salt and table salt. When 2-3% molybdenum is added to Type 304 or 304L, we create Type 316 (S31600) or 316L (S31603) stainless steel. They are sometimes referred to as the marine grades of stainless steel, since they are widely used for items such as boat fittings. They are also known as the acid resistant grades, since they have better corrosion resistance in some acids such as sulphuric acid. But their range of applications is wide, from building facades in aggressive atmospheres to piping onboard chemical tankers. Halfway between the ferritic and austenitic stainless steels is a family called the duplex stainless steels, which are about 50% ferrite and 50% austenite. Because of this duplex structure, they are resistant to stress corrosion cracking, which can affect the austenitic stainless steels in hot waters containing chlorides. The most common duplex stainless steel is 2205 (including both S31803 and S32205) and it is used in many applications such as hot water tanks. Nitrogen (N) is added to some stainless steels, but is very important in duplex grades. It has several beneficial effects. Like nickel, nitrogen promotes austenite (especially important for welding) and, like molybdenum, it improves resistance to pitting and crevice corrosion. It also increases strength. Duplex stainless steels are inherently stronger, but a grade such as 2205, which contains about 0.15% nitrogen, has over twice the yield strength of Type 316L. Thus, 2205 is commonly used in tanks for seagoing chemical tankers where both strength and corrosion resistance are required, and for components such as rods and connectors for glass curtain walls in public buildings where the high strength means that the components can be small and so make the structure seem lighter and more transparent. There is one more family – the precipitation hardening stainless steels. This is a specialised family which has very high strength achieved by adding elements such as copper, which form very fine particles during heat treatment. They generally have slightly higher corrosion resistance than the martensitic stainless steels but, at best, they have slightly less resistance than Type 304. They are commonly used in the aerospace and defence industries, but also find use in items such as pump shafts. 17-4PH (S17400) is a typical example. In addition to the common grades mentioned above, there are many more specialised grades of stainless steel for applications which require greater corrosion resistance or higher strength. Three which are listed in the accompanying table are Alloy 904L (N08904), which was originally developed for sulphuric acid service, the super-austenitic grade Alloy 254 (S31254), representing a group of 6% Mo stainless steels; and the grade Alloy 2507 (S32750), representing a group of super-duplex alloys. The last two are ‘seawater resistant’ – they will not suffer pitting or crevice corrosion when immersed in ambient temperature seawater. There are also grades developed for such special needs as improved machinability. Cast versions of most wrought grades are also available, usually slightly modified to improve castability. Oil Companies are responding to the demand to operate their businesses in a sustainable way. Measures adopted include seeking to reduce emissions and to maximise their production of so-called “stranded” gas which otherwise can make no contribution to the world’s energy demand. In this climate it is likely that the oil and gas industry will increasingly seek to justify any aspect of its business, including its choice of materials, in order to boost its ‘sustainability rating’. Nickel-containing stainless steels and nickel alloys play an important role in providing corrosion resistant, and hence leak resistant, materials of construction for projects internationally. Some of these materials also play a critical role in handling gas production, particularly in liquefied form, thus helping to develop difficult-to-access gas reserves. Mechanical and Physical Properties For most corrosion resistant applications, strength is not a key issue. There are exceptions, such as pressure vessels, and here the high strength of duplex grades can make them attractive. A characteristic of the austenitic stainless steels is that they work harden easily – that is, their strength increases rapidly when they are formed at ambient temperatures, such as in rolling or wire drawing operations. The accompanying table (below) shows the large increase in strength of Type 304 in the 1/2 hard condition. This characteristic is valuable in items like bolts and springs. Two important physical properties are thermal conductivity and thermal expansion rate. The common austenitic stainless steels, such as Type 304, have lower thermal conductivity than carbon steels and this is useful in applications such as cappuccino cups and thermos flasks. Their rate of thermal expansion is also greater than ordinary steel (but less than materials such as aluminium) so care must be taken during welding to ensure that the recommended jigging and tacking procedures and welding sequences are followed. Corrosion Resistance When carbon steel rusts, it does so by uniform corrosion – the entire surface of the steel corrodes more or less uniformly. Except in special environments, such as strong acids, stainless steels do not corrode in this way. If corrosion does occur, it is normally by localised corrosion and the most common forms of this are as follows: Pitting is localised corrosion at inpidual sites on the surface of stainless steel. Pitting starts at points of weakness in the protective oxide film, such as at manganese sulphide inclusions on the steel surface. Crevice corrosion takes place where physical crevices are present, such as at the joint between two overlapping sheets of stainless steel, in the crevice between a stainless steel flange and a non-metallic gasket or under surface deposits. The mechanisms of pitting and crevice corrosion are similar and both most commonly occur in chloride environments. But crevice corrosion occurs more readily since it is assisted by the existence of a physical crevice, whereas pitting has to initiate on a surface which is effectively flat. It is often not possible to control environmental factors such as the amount of chloride or the temperature, so it is usually necessary to choose a sufficiently corrosion resistant grade for the service. An indication of pitting and crevice corrosion resistance is given by the ‘Pitting Resistance Equivalent’ (PRE) number: PRE = %Cr + 3.3%Mo + 16%N This formula shows the beneficial effect of chromium, molybdenum and nitrogen and illustrates why Type 316, with 2-3% Mo, has better resistance than Type 304 to marine environments. However, for resistance to corrosion when immersed in seawater on a longterm basis, it is necessary to move up to a grade with a relatively high PRE number, such as a super-austenitic 6% Mo grade or a super-duplex such as 2507. Chloride stress corrosion cracking (SCC) can occur in chloride-containing solutions at elevated temperature, normally above 50 degrees C, when tensile stress is present. It particularly affects austenitic stainless steels, and a common failure observed in the field is cracking from the outside of tanks or pipes carrying hot fluids. For example, if a water leak occurs into insulation on the outside, chlorides can concentrate through evapouration, and SCC can take place because of the tensile stresses present in the outside surface of pipes and tanks. Chloride SCC is most comonly overcome by using a duplex stainless steel, such as 2205, or a grade with a higher nickel content, such as a 6% Mo material or high-nickel alloys like Alloy 825 (N08825). Ferritic stainless steels are very resistant to SCC but grades with equivalent pitting resistance to the austenitic grades have other major drawbacks. Intergranular corrosion (IGC) is preferential attack at the grain boundaries of a stainless steel and is commonly associated with welding. If stainless steel is heated into a sensitising temperature range, such as can occur in the heat affected zone of a weld, then chromium can combine with carbon in the steel to form chromium carbides in the grain boundaries. Such a stainless steel is said to be ‘sensitised’. Around each chromium carbide particle is an area low in chromium so that, when the material is placed in a corrosive environment, attack of these low-chromium regions can occur. This is called IGC. The most common way today to avoid IGC is to specify a low carbon ‘L’ grade of stainless steel when welding, such as Type 304L . In the past, when it was difficult for mills to achieve low carbon levels, titanium (Ti) or niobium (Nb) were added since these elements preferentially combine with carbon and so leave the chromium unaffected. Grades containing these additions include Type 321 (S32100) containing Ti and Type 347 (S34700) containing Nb. Galvanic corrosion can occur when different metals are in contact in an electrically conductive liquid. Stainless steel is not normally corroded in such a galvanic couple, since it is usually the more corrosion resistant of the two metals and acts as the cathode. When the other metal which is in contact with the stainless steel is less corrosion resistant, it acts as the anode and corrodes preferentially. The rate of corrosion of the second metal can be rapid if its surface area is small relative to the area of the stainless steel cathode with which it is in contact. An example of this would be the use of galvanised steel fasteners to hold stainless steel sheets, a poor design unless the system is always dry. Galvanic couples are not necessarily a problem and can, in fact, be used to benefit in some designs. Applications Stainless steels find use in a very wide variety of applications. Some typical examples are: Consumer goods: Applications here include domestic kitchenware and tableware, kitchen sinks, laundry equipment and electrical and electronic appliances. Architecture, building & construction: Stainless steel has been used in numerous famous buildings. The Chrysler Building in New York, the world’s tallest building when it was built in 1929, used Type 302 (similar to Type 304) for the roof and upper structure. Type 316 is used to clad the outside of Petronas Twin Towers in Kuala Lumpur, currently the world’s tallest buildings, and Jin Mao Tower in Shanghai, the third tallest. More common applications are balustrades, column wraps, roofing and guttering, signage, curtain wall supports, light poles, elevator doors and public seating. Stainless steel rebar is used in bridges, barrier walls and decking to extend the life of critical areas of roadways and marine structures. Food and beverage industry: Type 304 and, in more aggressive situations, Type 316 are widely used in this industry for food and beverage production (milk silos, cheese vats, beer and wine fermenters, fruit juice tanks and piping), storage (wine tanks, beer kegs), cooking (large commercial kitchens) and serving (display cabinets, bench tops). Stainless steel equipment is easy to clean (sanitize) and also preserves the purity of the food. Transportation: A wide range of both decorative and functional components are fabricated from stainless steel, such as automotive exhaust systems, fasteners, trim, wheel covers and windscreen wiper arms; passenger railcars, coal wagons, bus frames and milk tankers; and seagoing chemical tankers. Chemical, petrochemical, oil and gas, pulp and paper industries, and power generation: This field represents a very persified market for stainless steel with many specialised applications such as heat exchangers, vessels for various types of chemicals, pipe, fittings, valves, pumps, mixers, high temperature furnace equipment, components for nuclear reactors, and gas and water turbines. End of Life When a system which uses stainless steel components reaches the end of its useful life, and if the equipment cannot be reused, it should always be recycled. Stainless steel, especially the nickel-containing grades, has a high scrap value and can be recycled to produce new stainless steel without any loss of quality. Most stainless steel today is made using a significant percentage of scrap stainless steel. Footnotes 1 High temperature grades and applications are not covered here. 2 The traditional AISI (American Iron and Steel Institute) numbering system groups stainless steels into 300, 400 etc series, such as Type 304, Type 430 etc. The newer UNS (Unified Numbering System) uses numbers of the form S30400 and S43000 for these same grades. Grade UNS No. Family Crc Nic Moc Nc C(max) Otherc PREc, e Yield strength MPa(min)b Tensile strength MPa (min)b Elong % (min)b 430 S43000 ferritic 17 0.12 17 205 450 22 420 S42000 martensitic 13 0.15 min 13 1480c 1720 8c 304 S30400 austenitic 18 9 0.08 18 205 515 40 304 ½ hard 760 1035 7 304L S30403 austenitic 18 9 0.03 18 170 485 40 316 S31600 austenitic 17 11 2.1 0.08 24 205 515 40 316L S31603 austenitic 17 11 2.1 0.03 24 170 485 40 904L N08904 austenitic 20 25 4.5 0.02 1.5Cu 35 220 490 35 2205 S31803 S32205 duplex 22 5 3 0.15 0.03 34 450 620 25 17-4PH S17400 precipitation hardening 16 4 0.07 4Cu 0.3Nb 16 1170 1310 5-10 Alloy 254 S31254 superdaustenitic 20 18 6 0.20 0.02 0.75Cu 43 300 650 35 Alloy 2507 S32750 superdduplex 25 7 4 0.28 0.03 42 550 795 15 a 0.2% proof stress b Annealed condition except for grades 420 and 17-4PH which have been heat treated and 304 ½ hard which has been cold worked, the intention in each case being to increase strength and hardness c Typical values d The term “super” is commonly used when the PRE number of the alloy is 40 or more e PRE = Pitting Resistance Equivalent (see text) By Gary Coates, Technical Director, Nickel Institute and Dr. David Jenkinson, Director Nickel Institute Australasia.

The downstream applications of industrial metal pipe fittings are extensive and involve the major industries of the national economy. Among them, petrochemical, nuclear power, thermal power, shipbuilding and military industries are the representative industries for their applications, especially the application of special metal fittings in these industries. . Through the analysis of industrial metal pipe fittings in several key industries and demand forecast application of the foreseeable future market prospects. 1. petrochemical industry Industrial pipe and pipe fittings as a mass transfer equipment in the pipe equipment, oil refining, chemical equipment for an important segment of the field. Commonly used industrial metal pipe materials are stainless steel, carbon steel, etc., are widely used in oil refining, chemical production in the pipeline connection, the other materials are titanium, aluminum, nickel, zirconium, etc., usually selected for specific use tube material . In recent years, refining, petrochemical enterprises to increase production capacity to intensify the transformation of large-scale, new large-scale oil refining, chemical engineering projects have been prepared by the localization of oil hydrogenation equipment and successively developed ethylene cracking and subsequent processing of key equipment Pulling, China’s refining, chemical production equipment manufacturing industry is growing rapidly. As the long-term operation of petrochemical equipment in high temperature or low temperature, high pressure, strong corrosion and other special circumstances, special metal materials in the petrochemical equipment in the proportion of demand for high, the current petrochemical industry, industrial metal fittings in the proportion of special metal pipe is about 50 / RTI & gt; With the increase in the proportion of poor use of crude oil, hydrogenation technology to promote the application of long-distance oil and gas pipeline construction, new coal chemical industry to accelerate the development trend of the application of special metal fittings will be more and more widely. The traditional single anti-corrosion technology and materials can not meet the needs of the development of oil and gas fields, therefore, oil and gas fields on the high steel grade, high corrosion resistance, low temperature and other pipe needs continue to increase. As the oil and gas field medium composition, pressure, temperature and other large difference between the corrosion environment, a large number of high corrosion resistance alloy will cause increased production costs and corrosion of the waste of alloy materials, so the development of both oil and gas fields to ensure safety and transportation, A new type of bimetallic composite materials has become the focus of the major oil and gas companies, bimetallic composite pipe and pipe products, the market demand is also the market demand is very high. getting bigger. “Petroleum and chemical industry,” second five “plan” forecast, “second five” during the industry average growth rate will remain at 10% or more to petrochemical industry, industrial metal pipe industry, the average annual growth rate of 10% and special metal pipe fittings A conservative estimate than 50% in 2015, China’s petrochemical industry, industrial metal pipe fittings and special metal pipe market size will reach 40 billion yuan and 20 billion yuan. 2. coal chemical industry China’s coal reserves are rich, accounting for 11.60% of the world’s total coal reserves. Since the founding of the country’s primary energy production and consumption of coal in the long-term ratio of more than 70%. According to the Ministry of Land and Resources data, as of the end of 2010, China’s total coal resources forecast of about 5.6 trillion tons, of which 1340.83 billion tons of resources have been identified. Relying on the rich coal resources, China’s coal chemical industry has been a good development. “Eleventh Five-Year” period, China’s coal chemical engineering construction total investment of about 500 billion yuan, China’s nitrogen fertilizer, calcium carbide, coke and other traditional coal chemical products production capacity, continue to rank in the world. At the same time, with the role of oil substitution of new coal chemical technology has made great progress, driven by high oil prices, the emerging coal chemical industry is the emergence of rapid development momentum. “Twelfth Five-Year” period of coal chemical industry investment will be China’s coal chemical metal pipe fittings and special metal pipe to bring new market demand. 3. nuclear power industry In the construction of nuclear power, fluid gas delivery requires the use of a large number of industrial pipelines, pipe connections to use a large number of pipe fittings. The medium of the nuclear tube is mainly composed of saturated steam, condensed water, radioactive water vapor heavy water, irradiation corrosive substance, radioactive medium, dilute sulfuric acid and lye, carbon dioxide, sodium, helium, oil and vacuum. Special, complex, harsh, coupled with a large amount of large, demanding, so a large number of nuclear power fittings using nickel-based alloys, titanium, zirconium and other special metal materials. In recent years, China’s nuclear power infrastructure investment accelerated. According to China Electricity Council statistics, in 2011 China’s nuclear power infrastructure investment reached 74 billion yuan, from 2007 to 2011, the average annual growth rate of nuclear power investment of more than 70%. From the perspective of China’s energy demand and supply situation, the development of nuclear power is an inevitable choice to ensure energy security in China. In October 2012, the State Council approved the “Mid- and Long-Term Development Plan for Nuclear Power (2011-2020)”, Kilowatts of nuclear power installed capacity of the target, under construction nuclear power installed capacity will be slightly more than 20 million kilowatts is expected in 2015 China’s nuclear power with industrial metal fittings and special metal fittings market capacity will reach 2.9 billion and 1.7 billion. The market of nuclear power fittings is pided into two parts: pipe fittings and pipe fittings. Many enterprises make petrochemical and thermal power market for a long time. The production technology is mature and it is easier to enter the nuclear power market after upgrading according to the nuclear power quality assurance system. At present, there are nearly 20 domestic and foreign manufacturers of pipe fittings which are qualified to participate in nuclear power projects. Chinese and foreign enterprises basically share half of the country, but foreign integrated group companies possess nuclear island main steam piping and fittings experience, Grade pipe market, the vast majority of domestic enterprises can only provide the nucleus level 2, level 3 of pipe fittings. 4. thermal power industry Thermal power plants require a significant amount of pressure piping and fittings to carry high-temperature fluids. In order to improve the efficiency of coal-fired power generation and protect the ecological environment, China has vigorously developed super-critical thermal power units with low coal consumption, low pollution and high efficiency in recent years. Thermal power units Industrial metal pipe fittings, especially those used in the four major thermal power plant pipe (main steam pipe, reheat steam pipe hot section, reheat steam pipe cold section and high pressure water supply pipe) to be subject to long-term high temperature and high pressure steam and high-speed fluid substances Erosion corrosion, the quality of the four major pipeline operation is essential. With the development of large-capacity, high-parameter, ultra-supercritical and water-saving environment-friendly units, the four large pipe fittings are required to increase the caliber and have better performance of high temperature resistance, high pressure resistance and corrosion resistance. , The use of P91, P92, P22 and WB36 have excellent heat resistance, high pressure performance of special metal materials, special metal pipe fittings are used for a large number of supercritical, supercritical parameters such as thermal power units in the pipeline. 5. shipbuilding industry As an important component of marine pipeline system, industrial metal pipe fittings are widely used in ships and offshore engineering equipment, and play the role of fluid and gas medium transportation. By the impact of the global economic crisis lag, the international shipping market downturn, China’s shipbuilding industry, industrial output growth slowed, but overall to maintain growth. The marine engineering equipment industry, as the material and technical foundation for the development and utilization of marine resources, has become the most promising field in the field of shipbuilding in the context of the increasing importance of continental shelf resources in China. Marine and marine engineering in the fluid, gas medium, including crude oil, chemical gases and other corrosive substances, while the ship metal pipe fittings exposed to long-term humid air, marine equipment, pipe fittings need to be soaked in seawater, so strong corrosion resistance Of the special metal materials such as titanium, nickel-based alloys have been gradually applied to ship metal pipe fittings, especially marine equipment, metal pipe manufacturing. 6. the military industry Military industry is a typical high-end equipment manufacturing industry, not only assume the transformation of China’s manufacturing industry an important task, but also China’s core science and technology source and driving force, is the future independent intellectual property rights and patents, the main creator. Military equipment, including military aircraft, aircraft carriers, nuclear submarines, military ships, tanks and so on. Military industry is the earliest use of special metal materials industry, and then gradually into the special metal materials, chemical, civil nuclear power, thermal power, ships and other fields. Pipe fittings as an important part of the military equipment pipeline system, but also a large number of special metal materials used to support military equipment to high-tech, modern direction. Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Despite China’s signal to reduce its excess steel production capacity, industry executives said, the country has declared a “war” metal, has produced a “devastating” to the rest of the world industry. The steel industry overcapacity in recent years has been the industry side time bombs, driving prices down, make some steel & steel pipes enterprises difficult to survive. China’s low cost metal producers has been widely quoted as the main reason for the excess. In particular, the world’s second-largest economy was accused of “dumping” cheap steel & steel pipes into the global market, to gain market share, because of the slowdown in domestic demand. But Beijing has denied any wrongdoing and said its cost is lower than other manufacturers. This is war, not trade Other countries, including India, Italy, South Korea and Taiwan, also considered contribution to the global steel surplus. Export said, every country has its own set of subsidies and problems, “caused a lot of problems, dumping steel in the international market. However, similar to the oil industry, despite the falling demand, some manufacturers in order to support prices in 2015 before slowing production progress has been slow. In addition, it says, the oecd economies such as China is expected to lead to the global steel industry capacity expansion, its share in the world ability is expected to increase by 2017 to 71.4%. There is no sign that the global iron and steel production in the short term is slowing down. According to the world steel association statistics, in March 2016, the global crude steel production is 385.7 million tons, down 3.6% compared with the same period in 2015, China’s crude steel production in March, 2016 to 70.7 million tons, up 2.9% in March 2015. In March 2016 of India’s crude steel output of 8.1 million tons, a 3.4% growth in March, 2015. Export said, “just according to the Numbers, China is by far the biggest problem”, accusing China of not complying with the international trade rules. “If your competitiveness is based on deception international trade rules, you can’t call it their own competitiveness. There is no trade is not fair, but the war. Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Seamless oil casing, oil and gas exploration in the largest amount of a pipe, it relies on male and female buckle buckle which is screwed inside and outside, will a series deep underground steel pipe work. Oil well casing is the lifeline of its quality directly affects the success of drilling operations and the service life of oil and gas wells, related to the oil fields and the manufacturer’s economic benefits. Seamless Oil casing failure is one of the main problems encountered for each oil field, particularly among the most serious failure of the threaded joint. According to statistics, the oil casing failure occurs in about 64% of accidents threaded connections, the domestic this figure is as high as 86%, securing oil casing threaded joints are the weak link in the oil casing string, therefore, increase the thread connection quality is a key factor in ensuring the quality of the column. Oil casing threaded connections used in the stress distribution directly determines the strength of the connection string. Stress distribution of the parts of the study, not only for manufacturers optimize oil casing thread design, casing and tubing used for predicting the performance provide the basis, but also to guide the proper selection and use of oilfield tubing and casing also has a certain reference value. Seamless oil casing joints Seamless oil casing joints are externally threaded male buckle and belt buckle female threaded screw together composed of male and female buckle buckle the contact surface, which is a helical surface, and the oil tube fitting force is more complex. Apart screwed contact pressure generated torque, but also by tension (self-weight of the oil casing), pressure (by the oil, gas or other media caused by) the role of such loads. Oil casing the joint force analysis involves material nonlinearity, geometric nonlinearity and complexity of the contact friction conditions and other nonlinear problems establish a complete and accurate mathematical model, an analytical solution is very difficult.

How to clean rusted carbon steel pipe? For the rusted carbon steel pipe, some people use cleaning, but when cleaning, it note that should a solvent, emulsion cleaning the steel surface, this method is only used as an anti-corrosion auxiliary means, for the real removal carbon steel pipe rust, the role is not strong. In clear carbon steel pipe rust, you can also use steel brushes, wire ball and other tools, such appearance loose oxide, rust easily removed, but not up to the requirements of corrosion. Another method is to remove the rust pickling, although this method can achieve a certain degree of cleanliness, but easy on the environment caused by pollution, so it is not recommended that you use. The best method is to use spray rust, leaf through a high-power high-speed rotary motor driven jet, so that grit, steel shot, wire segments, minerals and other abrasive under the centrifugal force on the stainless steel surface spray treatment. Rust is the result of high-power spray jet vane motor driven high-speed reverse, the grit, steel shot, wire segments, abrasive minerals under the effect of centrifugal force on the pipe exterior spray and disposal, shot blasting machine can completely eliminate rust, oxides and dirt, and the ferocity of the abrasive tube shocks and under the effect of friction, but also to reach the needs of the average roughness. Spray rust, can extend the appearance of physical adsorption tube effect, and can enhance the appearance of the pipe coating mechanical adhesion effect. Thus, the injection pipeline corrosion rust is rust fantasy method. In general, abrasive blasting is mainly used inside the tube looks disposal abrator surface rust mainly for pipe surface disposal. Importance in the production of surface treatment of the importance of strict control of rust when the process parameters, in actual construction, carbon steel pipe coating layer of the peel strength value greatly exceeds the standard requirements to ensure the quality of the coating, in the same equipment on the basis greatly improve the technological level, reduce production costs.

Hydrostatic test is necessary to ensure the quality of welded pipe production equipment.  Currently, the market is on the market welded pipe hydrostatic testing machine working process: feeding, clamping, filled with water, pressure, pressure, pressure relief, the material. The process also constitutes a basic action hydraulic tube loop, most modern hydraulic test machine adopts PLC control, so that all the work automatically in order to complete the process and parameters with automatic recording function test results. According seal can be pided into radial seal and seal. Radial seal is used with the welded pipe with inner or outer diameter seal, seal pressure through expansion in order to achieve the purpose of sealing the wall, the advantage of steel clamping and extraction is very easy, reliable sealing, welded pipe axial force is small, is not easy to bend, but the sealing head structure more complex specifications more, and the welded pipe end there blind test; seal sealing material is to rely on the spout nozzle face seal compression to achieve the purpose of testing the advantage of simple structure, , common good, but the sealing material properties and water pressure proportional and servo control systems require higher.  Pipe hydrostatic testing machine during the pressure test, the first sealing device right through the end of the test tube is sealed at both ends and low-pressure water injection, water injection process through the exhaust valve exhaust air in the tube, filled with water at low pressure, by increasing pressure device to inject high pressure water pipe pressurized until the required test pressure. After reaching the required test pressure holding pressure at the stipulated time, if the welded pipe is no leakage in the pressure test, deformation phenomena, proceed relief. Then open ends of the sealing device, the discharge pressure water pipe will be tested to the examination table visually inspected for suspicious penetration. Pressure test according to the standard required for the pressure curve during automatic recording device records.

Seamless steel pipe industry maintained a strong momentum of development, is an important material of national economic development. Seamless steel pipe is a kind of economy, it is widely used in petroleum, electricity, chemical industry, coal, machinery, military industry, aerospace and other industries, the countries all over the world, especially developed countries attaches great importance to seamless steel pipe production and trade. China’s economic growth impetus to the development of the seamless steel tube industry. From the perspective of international experience, rapid growth is not the product of all industries balanced growth, but driven by a few of the rapid growth of leading industry. Different periods of leading industry, leading industry to promote the transformation of the sustained and rapid economic growth. From the perspective of domestic experience: in the 80 s dominant industry, light industry, textile industry, etc.; In the 90 s, the leading industry is the foundation of industry and infrastructure, a new generation of household appliance, real estate, etc.; After 1997, due to the leading industry there “pause” situation, the economic slowdown. This situation finally change until 2002, a new batch of leading industries to the surface. Leading is residential, automotive, electronics, communication and urban infrastructure construction industry leaders of these are the final product properties. Among these pilot industry produced some investment industry, mainly iron and steel, nonferrous metals, building materials, machinery, chemical materials and equipment industry. The above two aspects, also caused the electric power, coal, oil and other energy industry and ports, railways, highways and other transportation industry growth. Is the industry’s rapid growth has been driving the market demand of the seamless steel pipe, promote the rapid development of the seamless steel pipe industry. Seamless steel pipe industry and the sustainable and rapid development of domestic seamless steel tube market is currently in consumption growth opportunity. Consumption of domestic seamless steel tube will maintain rapid growth, the development of domestic seamless steel tube provides a favorable opportunity. One is the energy, transportation, petrochemical pipeline needs not reduce, high-performance varieties of rapid growth. The seamless steel tube in the energy, transportation, construction and maintenance of petrochemical facilities still occupied the position of steel market is very important. In recent years, the rapid increase of the demand for high performance and new varieties, such as high performance oil well pipe, large diameter power plant boiler pipe, corrosion resistance, low temperature resistance of petrochemical pipe and stainless steel tube, etc. Two, oil, natural gas, refined products, coal slurry, coal slurry pipeline fluid such as pipeline, especially for the demand of the high strength pipeline will rise sharply. Three is the construction rapid growth, high grade space grid tube construction demand rapid growth. Fourth, to the increasing demand for high technical content of steel pipe. Automotive, home appliances, shipbuilding, equipment manufacturing industries such as the demand of the seamless steel pipe, variety and quality requirement enhances unceasingly, all kinds of seamless steel tube is to develop in the direction of high technology. Source: Zhejiang wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Due to its advantages in materials, the application of stainless steel tube has been comprehensively promoted. As an important material in the pipeline. Stainless steel tube has obvious advantages in the market. Different from ordinary steel pipe, stainless steel pipe is made of alloy. Transportation, stainless steel pipe is mainly used for oil and gas transportation. Compared with ordinary transportation, pipeline transportation has more important significance. As a result, manufacturers continue to promote it. At the same time, with the development of the city, the stainless steel tube plays the most important role in the city construction. At most, it is a new mode of transportation, which is cheaper than other means. In order to meet the market demand, the number of stainless steel tube manufacturers will continue to increase. Now, stainless steel tubes are very popular. In the study of the stainless steel tube, we found that the stainless steel pipe has the air part, which can be used for conveying fluid, so the stainless steel tube is used in many fields. Has a good resistance performance, so in the oil, natural gas transportation is very easy and convenient. In the future, we can see more of the stainless steel tubes used in our lives. With the development of technology, the performance of stainless steel tube also has a lot of breakthrough. People can see stainless steel tubes used in every aspect of life. Outside, in the building construction, people can see parts of the stainless steel pipe. With high utilization rate, good effect, simple manufacturing process, low waste of materials, and many countries are promoting the use of stainless steel pipe. Now, the stainless steel tube has been widely used. Source: Zhejiang wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

If your elbow is a short radius it is 1 times your nominal pipe diameter. If it is a long radius it is 1 1/2 times your nominal pipe diameter.show me the exact pattern of long radius. (90/2tan*Dia*1.5*25.4) (45/2tan*Dia*1.5*25.4) u will obtain Ur answer in (mm) For 90 degree elbow (Dia*38.1) this formula used for only 90 degree elbow. For 45 degree elbow (45/2of tan*Dia*1.5*25.4) this answer obtained in (mm).

Resulting oil pipeline leakages is for many reasons, there are some followings below.  Some one-sided pursuit of profit, reduction of investment in safety protection facilities fierce competition in the market economy, in order to reduce costs, the pursuit of high profits, people are quick success, often there are chances, willful neglect of safety, reduction of safety protection facilities investment. In addition, state-owned oil company has been regarded as a leading enterprise, since it is the state-owned enterprises on the “stand toss”, it is this misconception makes some managers ideologically careless, negligent neglect of production and construction process management, the production site run, run, drip, leak precisely the consequences of its mismanagement, can benefit from a variety of spill management often find loopholes. Piping design unreasonable reasons exist congenital defects resulting pipeline is one of the main oil pipeline leak. Usually through the pipe connection part of the sealing structure and the sealing material or pipes conveying the medium pressure, temperature, nature or environmental conditions incompatible. During pipeline installation, failure to comply with operational process of order, it is bound directly related to pipeline installation quality, thereby affecting the runtime pipeline leakage.  Failure of the material forming the facility is to produce the main direct cause of leakage. Therefore research material failure mechanism is an effective means to prevent leakage. According to statistics, corrosion, cracks, wear, etc. leading to material failure, resulting in leakage of the main reasons. If a pipe weld porosity, slag or no penetration, cast iron pipe cracks, blisters; pipeline damaged by abrasion; aging pipes; stress concentration caused by intensity decreased; seal failure, and this will lead to pipeline leakage.  For the above reasons led to the oil pipeline leakage, and take effective measures to prevent leaks to prevent leakage build up layers of defense. Firstly, ideologically, it should be to establish a “spill prevention is equivalent to increase economic efficiency” understanding. Secondly, the development of a sound management measures to strengthen labor discipline, which is an important measure to prevent leakage. Secondly, doing preparatory work before pipe installation in the preliminary stages of the pipeline should understand and master the specific circumstances: including pipeline process, the nature of the job, the use of pressure, environmental conditions and special requirements; allowable leakage because of the size of the pipe is directly related pipeline project investment and operating safety, and must therefore be based on extensive research, strictly in accordance with the relevant national standards to determine allowable leakage pipeline, so that “temper justice with degree”; under normal conditions of use predictive pipeline to achieve durable leak-free status sex. While for pipeline leak may occur during operation and contingencies, to formulate a practical and reliable maintenance preventive measures.  It has proved that leaks often require subsequent treatment doubled the price to pay. In the pre-construction and construction take active preventive measures that can effectively reduce the occurrence of leakage and reduce the harm. Therefore, the emphasis Spill Prevention, conducted ahead of the investment, both necessary, but also economic benefits.

How to measure the length of steel pipe? According to the different requirements for the process, there are a variety of method of measuring the length of steel pipe following: 1, grating length measurement The basic principle is: the outside of the pipe ends were set two fixed-length grating, rodless cylinder driven grating measurement of the length of pipe near the pipe ends by optical interference phenomenon. its characterized by high accuracy. Grating expensive and difficult to maintain, very sensitive to dust and venues vibration. 2, the camera length measurement. The camera length measurement is the use of image processing steel tube length measurement, the principle is equidistant series of photoelectric switches installed in a section of the pipe conveyor roller, plus the light source and the camera on the other section. When the steel pipe after the region, according to a particular photoelectric switch through over cameras capture an image on the screen to determine the length of pipe. Can be achieved online measurement, pipe length data can be obtained through the length measurement area, no interval. If you do not have ad hoc light source, the steel pipe will be subject to interference from external light, and the adoption of ad hoc light steel pipe tube end chamfering high brightness of light reflected strong, likely to cause reading errors. 3, the encoder length measurement Principle is installed in the cylinder at the encoder, the use of the cylinders to promote the movement of the pipe in rollers, equidistant series of photoelectric switches installed on the other side, when the steel pipe encountered cylinder promote the tube end when the photoelectric switch, the readings recorded from the encoder converted the stroke of cylinder, so that we can calculate the length of the tubes. Its characterized by the pipe length measurement rising. In addition, photoelectric switches detect some error, may need to be fully measured. 4, the improved encoder length measurement This method is an indirect measurement, measured indirectly by measuring the distance between the two end faces of the steel pipe with the respective reference point, the length of pipe. Pipe ends each set 1 car length measurement, initial position zero bit, spacing of L. Then the Mobile Editor length to each steel pipe, tube ends walking distance (L2, L3), L-L2-L3 is the length of the tubes. This measurement is to overcome the large volume of steel pipe production complex environment of the scene, measuring mechanism can not pass through the lower part of the steel pipe support stand difficulties. This method is easy to operate, measurement accuracy within ± 10mm Repeat accuracy ≤ 5 mm.

There are many kinds of processing methods in seamless pipe bend production, let me introduce the fifth processing methods commonly used: Method: 1 stamping seamless elbow in production in the press by a core with a taper pipe expanding to the required size and shape. 2. Forging method: seamless pipe bend production by swaging machine will be at the end of the pipe or part shall be rushed out to the outer, commonly used swaging machine with rotary, connecting rod type, roller type. 3 rolling method: seamless elbows in production generally do not have the core shaft, suitable for thick wall pipe inside round edge. In the tube placement, peripheral roller push for circular edge processing. 4. Abscesses: seamless pipe bend in the production of a is placed in the inner tube rubber and above to punch the compression, the tube bulge forming; another method is hydraulic bulge forming, in the middle tube filled with liquid, liquid pressure to the pipe drum into the required shape, the bellows of production with the most is the method. bending forming method: seamless pipe bend production with three methods commonly used, a kind of method that extend method, another method called stamping method, the three roller method, 3 – 4 and, two fixed roller, an adjusting and, adjust roller is fixed from finished pipe is bent. Source: Zhejiang wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)