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Salt spray testing is an accepted method for assessing the suitability of stainless steel parts and fabrications that are likely to encounter chloride environments in service. For any particular part, tested under laboratory conditions, a difference in performance between say, 430 (1.4016), 304(1.4301) and 316 (1.4401) types stainless steel would be expected, but the test outcome is sensitive to the shape of the parts (designed-in crevices), surface finish and the test conditions. Using specific laboratory salt spray test data to assess if a particular stainless steel grade is suitable for a specific or ‘generic’ environment is therefore not appropriate. Salt spray test methods Salt spray testing is covered by the standards such as: ASTM B 117 – Practice for Operating Salt Spray (Fog) Testing Apparatus Tests durations may be up to 260 hours. BS7479:1991 – Method for Salt Spray Corrosion Tests in Artificial Atmospheres.  This supercedes BS5466:1977 and is equivalent to ISO 9227. The test duration’s range from 2 to 96 hours. The pass / fail criteria is that thers should not be any ‘visible’ staining on parts tested. The test acceptance criteria can therefore be subjective and need to be clearly defined for any set situation. This standard covers methods in three types of atmospheres: NeutralAcetic acidCopper accelerated acetic acid (CASS) Comparison of 316, 430 and 304 type stainless steel in salt spray testing Results from one testing laboratory, based on tests done to the ASTM B117 method suggest a 316 type stainless steel part could be expected to pass a 96 hour test using a 3% salt spray. Indications are that longer test times would not be expected to give satisfactory results. In contrast, 304 type stainless steel parts would not be expected to give satisfactory results in a 3% salt spray, but if the salt solution concentration is reduced to 0.3 %, then it is possible that a 304 type stainless steel parts may be satisfactory for test times up to 120 hours. This could also apply to 430 type ferritic or 431 type martensitic stainless steel parts. Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The high thermal conductivity of copper can not compensate poor thermal conductivity of  organic solid black particles resulting in decrease of heat transfer. Table 1 demonstrates the effect of fouling on thermal resistance of copper and stainless steel tubes with wall thickness of 0.049”. These calculations show that thermal resistance of stainless steel tubes in the fuel oil preheater will be less then thermal resistance of copper tubes, accumulated coked hard crust deposit of hydrocarbons. The thermal resistance of the tubes is only a part of total resistance of heat transfer, and the effect of fouling and tubing material can be accurately calculated in the process of the thermal design of a heat exchanger. CopperStainless Steelk- Btu/(hr ft deg. F)225.008.4t/k – (hr sq. ft deg. F)/Btu0.00001810.0004861Fouling 0.0050.005   (per TEMA)Total0.00501810.0054861Per Cent100%109.3% Where:  t/k-Thermal Resistance of the tubes, t-wall thickness, k- coefficient of thermal conductivity. Regretfully, TEMA Recommended Good Practice values of Fouling Resistances for Industrial Liquids do not take in consideration effect of tube material. If the actual Fouling Resistance of # 6 Fuel Oil in the heater made from stainless steel tubing equals to 0.0025, then:Fouling0.0050.0025Total0.00501810.0029861Per Cent100%   40% The coking of hydrocarbons accelerated at elevated temperature of heating tubes. The evaporation of light hydrocarbon residue fractions definitely accelerates coking. As a good practice, The Alstrom Corporation recommends to maintain the temperature of heating media about 120 deg. F above the outgoing temperature of the #6 heating oil or less. For instance, #6 Fuel Oil Outgoing Temperature, deg.FRecommended Temperature of Heating Media, deg.FMaximal Steam Pressure, psig120240101502703018030050220340100250370150 The excessive steam pressure can be used to size temperature regulator. These recommendations are valid for asphalt and other highly viscous liquids. For instance, heating syrups may result in carmelization of the fluid. Similar, but in less degree, phenomena occurs in shell & tube heat exchangers for water heating. Indeed, copper tubes are oxidized, resulting in fast accumulation of solid deposits. Copper has poor mechanical properties, particularly on elevated temperatures common in heat transfer. Tube-to-tube sheet joint of copper tubes with other materials commonly made by tube expansion. ASME Boiler & Pressure Vessel Code estimates efficiency if expanded joint 60-65%. Stainless steel tubes can be not only expanded but also seal welded to the tubesheet, resulting in 100% joint efficiency.  In this case, according to the Standard for Power Plant Heat Exchangers of Heat Exchange Institute, the metal temperature of welded joint can reach the maximum value permitted by ASME Code. After introducing 316 stainless steel tubes as a standard material of fabrication shell & tube heat exchangers and using expansion-welding technology The Alstrom Corporation was never reported about tube damage or leak in the tube-to-tubesheet joint.

The causes of disappointment can arise at any point in the long supply chain that often applies to a stainless steel project. This helps to explain why problems occur. Getting the appropriate knowledge to all parts of the supply chain is difficult and it only takes ignorance in one small part to create a problem later on. Importance of surface finish in determining corrosion resistance 1. Lack of knowledge in this area is a major cause of problems. Most specifiers and designers understand the importance of selecting a grade of stainless steel, for example 1.4301 (304) or 1.4401 (316). But surface finish is at least as important. The subject is fully explored in The Importance of Surface Finish in the Design of Stainless Steel. Briefly, a bright polishedsurface gives maximum corrosion resistance. A directional polish equivalent to the EN 10088-2 2K (Ra = 0.5 micron max), usually produced using silicon carbide (SiC) abrasives, will give adequate corrosion resistance in many severe environments notably heavy urban and coastal ones. A common surface finish achieved with 240 grit alumina abrasives has been implicated in the corrosion of stainless steel in urban and coastal environments. In some cases, surface roughness Ra values have been measured at well above 1 micron which is known to be inadequate in these environments. The lack of any specified surface finish on architectural drawings can be the source of the final problem. If, at any stage of the supply chain, there is any doubt about the appropriate surface finish, specialist advice should be sought. 2. Importance of post-fabrication treatments Apart from some specialised processes, welds in stainless steel always result in some degree of heat tint. Heat tint is essentially an oxidised surface which has a reduced corrosion resistance compared to the parent material. Therefore, the normal practice is to carry out some form of post weld treatment to improve the corrosion resistance. Details of these procedures can be found at: Post Weld Cleaning and Finishing of Stainless Steels Welding and Post Fabrication Cleaning for Construction and Architectural Applications Good fabrication practice always includes post weld treatment. Failure to do so can give rise to unnecessary cost of rectification later on. 3. Importance of segregating carbon and stainless steel Sometimes “rusting” of stainless steel turns out to be nothing of the kind. It is the rusting of carbon steel which has contaminated the surface of the stainless steel at some point in the production process. Possible sources of contamination from carbon steel include: Tools Lifting Gear, Ropes, Chains Grinding dust Cutting sparks Wire brushes Wherever possible, stainless steel and carbon steel should be fabricated in separate areas of the  workshop or better still in separate workshops. Where not possible it is important to clean down machines used for carbon steel before using them for stainless steel. Stainless steel surfaces should be protected with plastic coatings for as long as possible. 4. Importance of site management It is quite possible for everything to be done well in fabrication, only for the whole project to be spoiled by inappropriate practices on site. The issues outlined in 3. apply just as much to the site installation as anywhere else in the process. In addition, it must be remembered that what is appropriate for one building material is totally  unacceptable for another. For stainless steel it has to remembered that masonry and brick cleaners may contain hydrochloric acid sometimes called muriatic acid. If these fluids are to be used at all near stainless steel, care should be taken to protect the stainless steel surfaces. If splashes occur, they should be immediately washed off with water. Failure to do so will result in serious attack of the stainless steel resulting in expensive rectification costs 5. Importance of choosing correct grade for the application This aspect almost goes without saying. It is only this far down in the list because it usually is  considered. But if the “wrong” grade has been chosen the consequences can be severe. Some guidelines on material selection are given here. 6. Cleaning and Maintenance Some people think that stainless steel’s corrosion resistant surface somehow repels dirt and other contaminants. Like any surface stainless steel requires some maintenance. Guidance on this aspect can be found at Cleaning Methods for Stainless Steel Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Understanding joints, connections and the most common flange types used in the oil and gas industry is a core requirement to keep these levels of safety and attitudes the same. To ensure your always familiar with these, here are 6 of the most common flange types and a description of what they are best used for: Weld-neck Flange Complete with a tapered hub, these flanges are recognisable and used in high pressure environments. The flange is particularly useful under repeat bending conditions. Slip-on Flange A flange which is slipped over the pipe and welded both inside and outside to increase strength and prevent leakage. A favourite for engineers compared to the weld-neck due to their lower cost. Lap-joint Flange Used in conjunction with a lap joint stub end, the flange is slipped over the pipe but not fastened, unlike the slip-on. Instead the flange is held in place by the pressure transmitted to the gasket by the flange pressure against the back of the pipe lap. Threaded Flange Used in special circumstances, the threaded flange can be attached to the pipe without being welded. These are usually positioned on pipes with a deep wall thickness, used to create the internal thread. Blind Flange Manufactured without a bore, these flanges are used to blank off the end of piping, valves and pressure vessel openings. They are also most suitable for high pressure temperature applications. Socket-weld Flange With a static strength equal to the Slip-on flange, the Socket-weld is connected with the pipe with 1 fillet weld on the outside of the flange. Due to corrosion issues, some processes do not allow this flange. Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The value of stainless steel seamless pipe: It is worth noting that the stainless steel seamless pipe which can not rust, resolutely resist any form of corrosion and anticorrosion, but it is not completely immune. Only gold and platinum is completely from corrosion, stainless steel seamless pipe can say unlimited application is the most economical choice. The best thing to do is to keep it clean, in order to prevent rust and corrosion of stainless steel seamless pipe. Keep clean, stainless steel seamless pipe can come into contact with different kinds of environment and chemicals. Abrasive can break stainless steel anti-corrosion ability to refuse to change. Avoid using grinding material or brush. It is recommended to use soap and soft cloth to clean stainless steel materials, because they do not contain chloride. Stainless steel seamless pipe definition: Stainless steel is known as the iron and carbon compounds, mainly from 10.5 to 11.5% chromium content. Forming of stainless steel seamless pipe in the 19th century, but it was not until the early 20th century, stainless steel seamless pipe for mass production and extensive use. Chromium content of stain resistance of the secret was discovered. When the chromium and surrounded by oxide exposure to call chromium trioxide steel, and provide a corrosion barrier. Whenever chromium trioxide layer is broken, it can “repair”, and continue to create another piece of chromium and oxygen exposure interactions. Stainless steel seamless pipe brand: Is one of the most common grades of 304 stainless steel (18% of chromium and nickel 8%) and 316 (16% of chromium, nickel, 10% and 2% molybdenum, class of 304 stainless steel is the most common and widespread use of stainless steel seamless pipe, it was originally called 18-8-316 level, because it’s when the content of chromium and nickel, etc. Excellent corrosion resistance, is often referred to as “Marine grade stainless steel seamless pipe”, is used in food and laboratory equipment, medical equipment, threaded fasteners, grade 302 stainless steel after the may instead of 304 stainless steel material. Stainless steel seamless pipe: Stainless steel seamless pipe may be in the world today one of the most widely used metals. All the buildings, the watch of stainless steel seamless pipe, from the ancient skate blades. The Chrysler building was erected in 1930 in New York City top grade 302 stainless steel. The building of a recent test results show that the durability of stainless steel, the thickness of resistance element was found no corrosion or loss. St. Louis arch is one of the largest man-made monument in the United States. Concrete arch dam is nine hundred tons of stainless steel is covered from top to bottom. Since 1965, become the symbol of stainless steel appeared. Stainless steel seamless pipe is not only a good appearance is beautiful, many tools are made of stainless steel seamless pipe. Due to the superior strength and durability of the metal, homeowners and businesses choose to adopt stainless steel tools. An enterprise, there are even commented that “replace carbon tool steel, stainless steel tool to eliminate this risk, and should be viewed as any modern facilities of the essential link in standard operating procedures.” High-risk work, need reliable tool, in use process not corrosion or rupture. No one likes his house tool will rust. Recently, stainless steel seamless pipe is mainly used in architectural decoration, tableware, food machine, lathe machine, mainly energy, petroleum, chemical, machinery, automobile. Now as long as can use the iron industry, is inseparable from the stainless steel material. About: wilsonpipeline Pipe Industry Co., Limited Established in 2008, wilsonpipeline Pipe Industry Co., Limited is a professional organizer and one-stop-shop supplier for steel piping system products, including steel pipe and tube, forged flange and fittings, butt-welding pipe fittings, elbow, tee, reducer, stub end, gaskets, fasteners, valves, Sanitary Services etc. in China. We have devoted to providing the best solutions of steel materials and industrial equipment for our respected customers. We supply not only commonly used stainless steel materials (SS304/L,SS316/L,SS321), but also duplex and super duplex steel 1.4547, 1.4462, 1.4410 (S31254,S31803,S32750,S32760), special austenite stainless 310S, 347H, 317L, 904L…

High pressure stainless steel pipe fittings used in specific circumstances such as high pressure steam equipment, chemical high temperature and high pressure pipeline, pressure vessel of power plant and nuclear power, high pressure boiler fittings, etc. Pipe in the pipe system is the connection, control, turn, shunt, seal, support the action such as spare parts. Classification of pipe fittings 1, used for pipe connected to each other fittings are: flanges, articulated, pipe hoop, card sets and throat hoop, etc 2, change the direction of the stainless steel pipe fittings: elbows 3, change the pipe diameter of the pipe: variable diameter (reducer), reducing elbows 4, add piping branch stainless steel pipe fittings: tee, cross 5, used for pipe line seal: gasket, ribbons, cotton and ramie thread woven, blind flange plate, pipe plugging 6, used for pipe fixed pipe: snap ring, towing hook, rings, bracket, bracket, pipe clamp, etc stainless steel pipe fittings are parts of connecting pipe to pipe line. According to the connection method can be pided into the socket type stainless steel pipe fittings, flanges threaded stainless steel pipe fittings, stainless steel pipe fittings and welding stainless steel pipe fittings four categories. Use the same as the pipe materials.

Stainless steel flange is a kind of disc parts, are the most common in the pipeline engineering, stainless steel flange is used in pairs. In pipeline engineering, the flange is mainly used for pipe connection. In need of connecting pipes and all kinds of installation of a flange, the low pressure pipe flange can use silk, the use of more than 4 kg pressure welding flange. By sealing point between two pieces of flange and bolt fastening. Different stress of flange bolts with different thickness and use different. When water pump and valve, and pipe connection, the local equipment, also made the corresponding flange shape, also known as flange connection. Where there are two surfaces in the surrounding use of bolt connection closed connection parts at the same time, generally referred to as the “flange”, such as ventilation pipe connections, this kind of parts can be called “flange parts”. But this connection is only a partial equipment, such as flange connection and water pumps, not good called the pump flange parts “. Relatively small, such as valve can call “flange parts”. The Main functions are: 1, the pipeline of pipeline connection and keep the sealing property; 2, easy to change line a long period; 3, easy to disassemble pipeline; 4, easy to pipeline closed a long period. Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Due to the stainless steel pipe fittings sizes, according to the welding of stainless steel pipe fittings unique place, as far as possible reduce the amount of heat input, the manual electric arc welding, argon arc welding is adopted two kinds of methods, d > Φ 159 mm adopts argon arc welding, manual arc welding surface. D ≦ Φ 159 mm all use argon arc welding. stainless steel pipe fittings welding technical requirements are as follows: (1) manual arc welding with welding machine adopts dc reverse connection, when using dc argon arc welding is pick up; (2), it should be before welding wire with oxide coating on the surface of the stainless steel wire brush to brush off, with acetone to wash; Electrode should be in 200-250 ℃ drying 1 h, as you take; (3) the workpiece before welding groove on both sides of the 25 mm within the scope of the clean up oil pollution and so on, with acetone to wash groove on both sides of the 25 mm; (4) argon arc welding, the nozzle Φ 2 mm in diameter, extremely rich tungsten tungsten electrode, specifications Φ 2.5 mm; (5) argon arc welding of stainless steel, the back must be filled argon gas protection, to ensure forming on the back. Using the method of partial argon filling in the pipe flow for 5-14 l/min, positive argon gas flow is 12 13 l/min. Stainless steel pipe fittings backing welding seam thickness should be thin as far as possible, and the roots of the fusion outstanding, when you receive arc into a gentle slope shape, if there are any are-receive shrinkage cavity, polishing machine grinding. Must be within the groove arc arc, arc should fill arc crater and prevent the crack of arc crater.

The advantages of stainless steel pipe fittings are introduced: Such as stainless steel elbow, tee: stainless steel pipe fittings due to easy to clean, beautiful appearance,  does not rust and is widely used in various industries.  The disadvantage of stainless steel pipe fittings are as follows: Difference of heat transfer: unless for bonded aluminum or copper base, thermal conductivity is very poor.  This means that a cheaper stainless steel pipe fittings are not necessarily better than other products. Price is quite high: stainless steel is better, it is often more expensive. Upside, stainless steel cookware is very good,  can last a lifetime. Many people think that this is a one-time purchase, worth the investment. Stainless steel pipe fittings are generally easy to clean, stick to the food can make coating pot looks a bit more attractive.  Little hard work, however, are seen as worth many overall durability of these POTS and pans. The choice of stainless steel  cookware, there are some clean technique, can begin to work. In general, stainless steel, should be used after washing,  in order to avoid any potential, no matter how small, dyed.

The corrosion resistance of stainless steel decreases with the increase of carbon content, and therefore, most of the stainless steel and carbon content are low, the largest of no more than 1.2%, some steel Wc (carbon content) and even lower than 0.03% (such as 00 cr12). The main alloying element in stainless steel is a Cr (Cr), only when the Cr content reaches a certain value, the steel corrosion resistance. Therefore, general Cr stainless steel (chrome) content of at least 10.5%. Stainless steel also contains Ni, Ti, Mn, N, Nb, Mo, Si and Cu elements. With stainless steel material manufacturing flange pipe called stainless steel flange. Below we said the stainless steel flange production to the factory should have requirements. 1. The feed (according to the specification and user requirements for quality control) 2. The physical and chemical control (material) 3. The blanking (size control logo transfer control) 4. Hot forging lines (thermometer size control) 5. Heat treatment (temperature control) 6. Test (hardness, metallographic control) 7. Gold processing (size control) 8. Finished goods inspection (according to the standard to do sampling inspection control) 9. Identify (control) according to the requirements of standard 10. Package delivery (control) according to user requirements and specifications Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

1, hot forming Hot push bend forming technology is to use special elbow push system core machine,  mold and heating device, to set on the mold of billet in pushing forward movement, under the impetus  of the machine in motion is heated and hole enlargement and forming process. Hot push bend  deformation characteristics are based on volume before and after plastic deformation rule of metal materials determine the pipe diameter, pipe diameter bend  diameter, through the core module and control the deformation of the process, make the inner arc compressed  metal flow, the compensation to other parts of the thinned by hole diameter, wall thickness uniform Angle is obtained. Hot push bend forming technology has a good appearance, uniform wall thickness and continuous operation,  suitable for the characteristics of mass production, thus become the main forming methods of carbon steel,  alloy steel elbow, and also the application in some of the specifications of the stainless steel elbow forming. Forming process of the heating mode with intermediate frequency or high frequency induction heating  (heating can be multiple times or lap), flame heating and reverberatory furnace heating, adopt what kind of  heating mode according to the condition of forming product requirements and energy.    2, stamping   Stamping elbow is first applied to the forming process of the mass production of seamless elbow, at present,  the commonly used in the production of the specifications of the elbow has been replaced by a hot method or  other forming process, but in some of the specifications of the elbow because of less production quantity and  wall thickness too thick or too thin. When the products have special requirements are still in use. Elbow stamping elbow is used to outer diameter  of the same tube billet, use press press forming directly in the mold. Stamping elbow forming diagram as shown in figure Before stamping, the tube billet is put on a mold, the mold filling and end into the pipe, the upper die downward  movement began to suppress, through external constraints and internal model of the supporting role of bend forming. Compared with the hot pushing process, the appearance of the stamping forming quality is better than the former;  Stamping elbow outer arc in the tensile state during forming, compensate, and no other parts excess metal so the  outer arc of wall thickness thinning is about 10% or so. But due to apply to the inpidual production and the  characteristics of low cost, so the stamping elbow process used in small batch, more thick wall elbow manufacture. Cold stamping and hot stamping stamping elbow points two kinds, usually according to the nature of materials  and equipment capacity selection of cold or hot stamping. Cold extrusion of bend forming process is the use of dedicated elbow forming machine, pipe to be included in  the external formwork, upper and lower mold clamping, under the impetus of the push rod, tube billet model  along the internal model and reserved clearance sports and forming process.  Figure 15-8 for a manufacturer of stainless steel elbow in extrusion pictures of before and after extrusion. Using die cold extrusion process inside and outside the elbow and good appearance, uniform wall thickness,  size deviation is small, so for the stainless steel elbow especially thin wall stainless steel elbow forming more  made by this technology. This new process used by internal and external mold precision demand is high;  For pipe wall thickness deviation is more demanding. 3, other methods of forming Except the forming process of the above three kinds of commonly used seamless pipe bend forming and  using the tube billet after extrusion to outside, and inside the tube billet passed ball plastic forming technology.  But this process is relatively complex, the operation of trouble, not equal to the process, and the forming quality  is less used.

Reducer decorated capitulum is one of the chemical pipe fittings, used for two different diameter of the connection. Is pided into concentric reducer and eccentric reducer. Stainless steel reducer according to certain standards, and in the production process for production, ensure the production of the reducer can play an important role in the field of a certain industry and performance, can give full play to the role and value in the industry. Reducer in production need to use production standard is as follows: 1, control diameter: DIN standard (DN10-6), 3 a/IDF criteria (1/2 “to 6”), ISO standard (12.7-152.4 Ф Ф); 2, the international industry standard: DIN, ISO, SMS, 3 a, IDF, etc; 3, the product material: stainless steel 304, 316, 316 l. Reducer of forming hole diameter is less than reducer big end diameter of the tube billet, used in die forming along the tube billet diameter hole enlargement. Hole enlargement technology mainly to solve the reducer in the variable diameter is larger not easily by reducing forming, sometimes according to the requirements of the materials and products forming, expanding and reducing method of combination. In addition to the use of steel tube as raw material to produce reducer, the part of the specifications of the reducer can also be used steel plate stamping forming technology is adopted to improve the production. Drawing die shapes used by reference to reducing tube surface size design, use after blanking punching die, stamping steel stretch forming. In the process of reducing or expanding deformation, according to different materials and variable diameter, determination by cold pressing and hot pressing. Under normal circumstances, as far as possible by cold pressing, but the multiple variable diameter and cause serious work hardening of the thick or alloy steel, wall thickness of materials appropriate USES hot pressing.Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)