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Tube & Pipe Guangzhou 2017China (Guangzhou) International Tube & Pipe Industry ExhibitionDate: 6/28/2017 – 6/30/2017Venue: China Import and Export Fair Pazhou Complex, Guangzhou, ChinaConcurrent Expo: Guangzhou Metal & Metallurgy 2017 – 18th GuangzhouInternational Metal & Metallurgy ExhibitionGuangzhou International Tube and Pipe Industry Exhibition has become a industry grand meeting covering tube and pipe materials, products, equipments and technology which gained support from lots of enterprises.  Event news: Website: http://www.julang.com.cn/english/guanye/index.aspFuture Dates:Tube & Pipe Guangzhou 20182018-6Guangzhou, ChinaVenuesChina Import and Export Fair Pazhou ComplexNo. 380 Yuejiang Zhong Road, Guangzhou China Tel: +86-020-28-888-999 http://www.ciefc.com/OrganizersGuangzhou Julang Exhibition Co., Ltd.Room 3A04-3A06,Building A1, Xinghui Park,Huaming Road 29,Pearl River New City, Guangzhou China Tel: +86-20-38621295 http://www.julang.com.cn/

China Tube & Pipe Expo 2017China International Tube & Pipe ExpoDate: 2017-8Venue: Shanghai New International Expo Centre, Shanghai, ChinaConcurrent Expo: STEXPO 2017 – 10th Shanghai International Stainless Steel ExpositionChina International Tube & Pipe Expo  Event news: Website: http://www.tubexpo.cn/VenuesShanghai New International Expo Centre (SNIEC)2345 Longyang Road, Pudong New Area, Shanghai China Tel: 86-21-28906888 http://en.sniec.netOrganizers Metallurgical Council of CCPIT46 Dongsi Xidajie, Beijing China Tel: +86-10-65227956 http://mc-ccpit.com/

Pipeline Week 201726th Annual GITA Oil & Gas Pipeline Conference & ExhibitionDate: 10/3/2017 – 10/5/2017Venue: The Westin Galleria Houston, Houston TX, United StatesIn 2017, the global event will continue to deliver an invaluable forum for oil and gas pipeline industry professionals as it brings the GITA 26th Annual Oil & Gas Pipeline Conference and the 13th Annual PODS Association User Conference. Attendees will benefit from a robust program of operator presentations, dynamic panel discussions, informational technical sessions, and numerous networking functions. As always, the program will target key areas of regulatory compliance, implementation and use of new technologies, asset integrity, and industry best-practices. The conference will be buoyed by an exhibition space full of leading technology companies and service providers within the oil and gas community. The joint conferences and exhibition provide an unrivaled opportunity to interact on a personal basis. There’s no better place than Pipeline Week to freely exchange ideas and a wide range of viewpoints propelling the industry forward.  Event news: Website: http://www.pipelineweek.com/Future Dates:Pipeline Week 20182018-10Houston TX, United StatesOrganizersPennWell Corporation1421 S. Sheridan Road Tulsa, Oklahoma 74112, Tulsa United States Tel: +1-918-835-3161 http://www.pennwell.com/

Stainless steel from the invention to the actual industrial application of time span of about ten years: 1904-1906 French Guillet first of Fe-Cr-Ni alloy metallurgy and mechanical properties of the groundbreaking basic research; 1907-1911, the French Portevin And British Gissen found the Fe-Cr and Fe-Cr-Ni alloy corrosion resistance and completed the Guillet research work; 1908-1911 German Monnartz reveals the corrosion resistance of steel and put forward the concept of passivation , Such as the critical chromium content, the role of carbon and molybdenum effects. Soon, the practical value of stainless steel in Europe and the United States was recognized, industrial stainless steel grades have also come out: 1912 ~ 1914, Brearley invented 12-13% Cr of martensitic stainless steel and patent; 1911-1914, the Americans Dant-sizen invented ferritic stainless steels containing 14-16% Cr, 0.07-0.15% C; German Maurer and Strauss invented austenitic stainless steels containing 1.0% C, 15-20% Cr, <20% Ni , Then, on the basis of the development of the famous 18-8 stainless steel (0.1% C-18% Cr-8% Ni). In practice, high-carbon austenitic stainless steels were found to be very serious intergranular corrosion problems, after Bain proposed the theory of intergranular corrosion of chromium-poor, and in the early 30s on the basis of 18-8 stainless steel developed titanium, Niobium stabilized austenitic stainless steel, namely AISl321 and AISl347. The same period also invented the ferrite – austenite duplex stainless steel, and put forward the ultra-low carbon (C ≤ 0.03%) the concept of stainless steel, but limited to the metallurgical equipment and technology level can not be used in industry. As early as 1934, American Folog invented the precipitation hardening stainless steel, in the 40 ~ 50’s martensite, semi-austenitic precipitation hardening stainless steel began for military and civilian industries. This series is based on the United States Steel (U.S.Steel) successfully produced StainlessW as a starting point. In addition, in order to save nickel element invented the nickel-manganese to Cr-Ni-Mn-N series stainless steel, the United States AISl200 series steel. After World War II, due to the development of the fertilizer industry and nuclear fuel industry, greatly stimulated the development of stainless steel, and because of the emergence of oxygen steel, 1947 ultra-low carbon type of stainless steel began commercialization. In the mid-1950s, high-performance stainless steel with excellent corrosion resistance was developed. In the late 1960s, high purity ferritic stainless steels with martensitic aged stainless steel, TRIP (Transformation Induced Plasticity) stainless steel and C + N ≤ 150 ppm were successively developed. In recent 20 years, by various local corrosion damage accidents, and the chemical processing industry continue to adopt new catalysts and new technology, has been developed on the basis of resistance to stress corrosion, pitting corrosion resistance, crevice corrosion, corrosion fatigue Special stainless steel, such as duplex stainless steel, high molybdenum stainless steel, high silicon stainless steel. In order to meet the needs of deep drawing and cold pier forming also developed a special type of stainless steel easy to shape. At present, the stainless steel series is also constantly improving. Since the late 20th century, since the late 1960s, a variety of production of stainless steel refining equipment and continuous casting equipment production, the world has also been completed with titanium stabilized austenitic stainless steel to low carbon, ultra-low carbon austenitic stainless steel transition, Stainless steel production level has reached a new level. The History of Chinese Stainless Steel China’s stainless steel industry developed late in 1952, industrial production began. Since 1949, after the mass production of stainless steel with electric arc furnace, after the first production Cr13 type martensitic stainless steel, master production technology, and then mass production of 18-8 Cr-Ni austenitic steel, such as 1Cr18Ni9Ti, began in 1952. Followed by the development of the domestic chemical industry, and began to produce with Mo2% -3% 1Cr18Ni12Mo2Ti and 1Cr18Ni12Mo3Ti and so on. At the same time in order to save valuable elements of nickel, since 1959 to imitate Mn, N on behalf of the Ni 1Cr17Mn6Ni5N and 1Cr18Mn8Ni5N, 1958 to AISI204 steel by Mo2% -3%, developed 1Cr18Mn10Ni5Mo3N (204 + Mo), for the whole Cycle urea production plant to replace 1Cr18Ni12Mo2Ti. From the late 1950s to the early 1960s, industrial trial production of 1Cr17Ti, 1Cr17Mo2Ti and 1Cr25Mo3Ti and other non-nickel ferrite stainless steel and began to study the fuming nitric acid corrosion of high silicon stainless steel 1Cr17Ni14Si4ALTi (equivalent to the Soviet Union grade ЭИ654), this steel actually Is an α + γ duplex stainless steel. 60 years, due to the domestic chemical industry, aerospace, aviation, atomic energy and other industrial development needs and the use of electric furnace oxygen steelmaking technology, a large number of new steel, such as 17-4PH, 17-7PH, PH15-7Mo precipitation hardening stainless steel, C ≤ 0.03% of ultra-low carbon stainless steel 00Cr18Ni10, 00Cr18Ni14Mo2, 00Cr18Ni14Mo3 and Ni-free Cr-Mn-N stainless steel 1Cr18Mn14Mo2N (A4) have been successfully developed and put into production. Since the 1970s, in order to solve the chloride and stress corrosion problems of 18-8 Cr-Ni steel in the chemical and atomic energy industries, some α + γCr-Ni duplex stainless steel have been developed and put into production and application. The main steel grades There are 1Cr21Ni5Ti, 00Cr26Ni6Ti, 00Cr26Ni7Mo2Ti, 00Cr18Ni5Mo3Si2 (3RE60) and 00Cr18Ni6Mo3Si2Nb and so on. 00Cr18Ni6Mo3Si2Nb is to solve the Swedish brand 3RE60 prone to single-phase ferrite welding after welding, resulting in decreased corrosion resistance and toughness and the development of N, Nb α + γ duplex stainless steel. Into the eighties, the development and imitation of the N containing the second generation of α + γ duplex stainless steel to address chloride pitting corrosion, crevice corrosion and other local corrosion damage, such as 00Cr22Ni5Mo2N, 00Cr25Ni6Mo3N and 00Cr25Ni7Mo3WCuN, etc., not only China’s duplex Stainless steel system, but also deeply studied its structure and performance and N in duplex stainless steel in the mechanism of action. Since the seventies, China’s stainless steel research work in other important progress: the development of high strength and ultra-high strength martensitic aging stainless steel and put into industrial trial and application; the use of vacuum induction furnace, vacuum electron beam furnace and vacuum consumption Furnace smelting and mass production of C + N ≤ 150-250ppm of high purity ferritic stainless steel 00Cr18Mo2, 00Cr26Mo1 and 00Cr30Mo2; Mo content of ≥ 4.5% of high Mo and high MoN-containing Cr-Ni austenitic stainless steel, such as the successful development 00Cr25Ni18Mo5 (N), 00Cr25Ni25Mo5N and so on in the chemical, petrochemical and marine development areas such as access to applications in the solution of concentrated nitric acid corrosion and solid solution intergranular corrosion, the development of 00Cr25Ni20Nb and several ultra-low carbon high Silicon stainless steel. Since the eighties, ultra-low carbon steel and phosphorus content and α-phase amount of strict control of urea-grade stainless steel 00Cr18Ni14Mo2 and 00Cr25Ni22Mo2N two grades developed, their plates, tubes, bars, forgings and welding materials are used in the Large and medium-sized urea industry, and the results are satisfactory; as a result of some special steel smelting stainless steel have been built outside the furnace refining equipment, such as AOD (argon oxygen refining furnace), VOD (vacuum oxygen refining furnace) and has been put into operation, making China Stainless steel smelting technology to a new level. It not only makes the production of low-carbon, ultra-low carbon stainless steel easy, but also to achieve a significant cost reduction of stainless steel efficiency. As a result of Ti 18-8 Cr-Ni austenitic steel there are a series of shortcomings, the United States, Japan and other advanced industrial countries as early as 60 years has been achieved by the Ti-containing stainless steel to the widespread use of low-carbon, ultra-low carbon stainless steel Transition, and China is in 1985-1990 years to vigorously low carbon, ultra-low carbon stainless steel development, production and application of progress gratifying, such as the end of 1988 China’s low carbon, ultra-low carbon 18-8 stainless steel production accounts for China’s stainless steel Production of about 10%. However, compared with the advanced countries of stainless steel production and application (such as Japan, the United States and other countries with Ti 18-8 Cr-Ni steel production accounts for only about 1.5% of stainless steel), the gap is still large. In the 1980s, China developed nitrogen-controlled (N 0.05-0.10%) and nitrogen-alloyed (N> 0.10%) Cr-Ni austenitic stainless steels. The results show that N is a beneficial element in Cr-Ni austenitic stainless steels and duplex stainless steels. N element can enhance the sensitivity of intergranular corrosion of stainless steel to improve the corrosion resistance of stainless steel, in particular, to improve the corrosion resistance of stainless steel and other aspects of the mechanism. Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Pipeline Coating & Protection 2017The American conference on pipeline integrity technology and marketsDate: 11/14/2017 – 11/15/2017Venue: Hilton Houston Post Oak, Houston TX, United StatesPipeline Coating & Protection 2017 will bring together leading pipeline contractors, operators, pipe mills and pipe coaters, engineers and specifiers, researchers, raw materials and machinery suppliers to debate the latest pipeline protection technology and regional industry trends. It will provide a platform for all links in the supply chain to interact and discuss market needs, existing and potential technology innovations, and new products and services available to the industry. Experts from pipeline-related industries will have a unique opportunity to network and exchange their experience with colleagues and potential customers. Join us at the only American conference focused on pipeline coating and protection! Event news: Website: http://www.amiplastics.com/events/VenuesHilton Houston Post Oak2001 Post Oak Blvd., Houston, Texas, 77056-4401, Houston TX United States Tel: +1-713-961-9300 http://www.hilton.com/OrganizersApplied Market Information Ltd.6 Pritchard Street, Bristol, BS2 8RH, Bristol United Kingdom Tel: +44-(0)117-924 9442 http://www.amiplastics.com/

Pumps Valves and Pipes Africa 2017International Trade Fair for Suppliers to the following industriesDate: 5/17/2017 – 5/19/2017Venue: Gallagher Convention Centre, Johannesburg, South AfricaThe International event targeting Sub-Saharan Africa’s mining, water utility, national and local government, industrial and civil engineering, manufacturing food, beverage, dairy, brewing, agriculture and horticulture, petrochemical and pulp and paper industries.  Event news: Website: http://www.indutecafrica.com/Future Dates:Pumps Valves and Pipes Africa 20192019-5Johannesburg, South AfricaVenuesGallagher Convention Centre19 Richards Drive Midrand Johannesburg Gauteng, Johannesburg South Africa Tel: +27-11-266 3000 http://www.gallagher.co.za/Organizersdmg ems AfricaPO Box 650302, Benmore 2010, Johannesburg South Africa Tel: +27-11-783 7250 http://www.exhibitionsafrica.com/

IOGPC 20176th International India Oil and Gas Pipeline ConferenceDate: 4/20/2017 – 4/22/2017Venue: Mumbai, Mumbai, IndiaThe 6th International India Oil and Gas Pipeline Conference is designed by ASME Members in India in cooperation with ASME Pipeline Systems Division members globally. This unique, not-for-profit event, designed by engineers for engineers, provides a forum for the transfer of best practices and standards as well as technical transfer between key corporate players in the onshore pipeline industry. Over 2 days industry leaders, engineering professionals and policymakers from across India and internationally will meet to learn the state of the art of their industry, issues and priorities for moving forward. The conference promises to attract a highly distinguished panel of speakers. A networking reception will be held at the end of the 1st day of the conference.  Event news: Website: https://www.asme.org/events/iogpcOrganizersThe American Society of Mechanical Engineers (ASME)Two Park Avenue, New York, NY 10016-5990, New York United States Tel: +1-973-882-1170 https://www.asme.org/

Butt welding elbow is a kind of using steel by hot pressing molding technology or forging forming technology of production of the elbow, the connection method is through the elbow with the steel pipe butt welding, using resistance heat two artifacts along the entire face welded together at the same time, the two methods usually have butt welding and flash butt welding, high productivity, easy automation, so has won a wide range of applications. Butt welding elbow electrode should be kept dry, when using titanium calcium type should be 1 hour after 150 ℃ drying, low hydrogen type should be 1 hour after the 200-250 ℃ drying (can’t repeat drying, otherwise the skin easy cracking flake), prevent electrode surface sticky oil and other dirt, lest cause weld increased carbon content and affects the quality of weldment. When the welding elbow, carbide precipitation by repeated heating, reduce corrosion resistance and mechanical properties. Butt welding elbow during the welding process needs to be in accordance with the instructions and the form of actual control, make its elbow products can fully show the use of good characteristics and performance, ensure the quality of the good contribution and. The butt welding elbow generally have a 45 degree Angle, 90 degree Angle, 180 – degree Angle and so on, the material is carbon steel, alloy steel and stainless steel. According to its radius of curvature to points, can be pided into long radius elbow and short radius elbow. Long radius of bend radius of curvature is equal to 1. 5 times the pipe diameter, that is, R = 1. 5 d. Bend radius of curvature is equal to the pipe diameter, short radius R = 1 d. Type D bend diameter of R for the radius of curvature. If no specific instructions, general selection is 1.5 D bend. Sclerosing after welding is bigger, easy to crack. If using the same type of electrode welding, must be above 300 ℃ preheat and 700 ℃ or so slow cooling after welding. If cannot undertake the weldment heat treatment after welding, it should choose chromium nickel stainless steel electrode. To improve the gb elbow corrosion resistance and weldability and appropriately increased moderate stability element Ti, Nb and Mo, weldability is better, using the same type of chromium stainless steel electrode, should be above 200 ℃ preheat and around 800 ℃ tempering treatment after welding. If cannot undertake the weldment heat treatment, should choose chromium nickel stainless steel electrode. In gb elbow welding need to follow certain standards and forms, need according to the use of good form and process for making and welding, can fully show the value of a good contribution. Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

The design and manufacture of carbon steel elbow must be considered when the hardness of the carbon steel elbow, so how to improve the hardness of the carbon steel elbow? Through research we found that the carbon steel elbow need heat treatment process: carbon steel elbow heated to a certain temperature and heat preservation for a period of time, and then make it slowly cooling, called annealing. Hot bend annealing is a heat the steel to the phase change or part of the phase transition temperature, slow cooling after heat preservation heat treatment method. The purpose of annealing is to eliminate tissue defects, improve the organization make composition uniformity and fine grains, increase mechanical properties of the hot pressing elbow, reduce the residual stress. Carbon steel elbow is widely used in petroleum, natural gas, chemical industry, water and electricity, construction and boiler pipe butt welding elbow is forming process is complicated, need according to the use of the different material and welding, gradually forming under the certain pressure. The advantages of carbon steel elbow molding process: 1, don’t need tube billet as raw material, can cut down the cost of pipe equipment and mould, and can get any big diameter and wall thickness is relatively thin, the size of the head. The size of the head material is special, don’t need to join the pipe material, easy to control during machining. 2, does not need tube billet as raw material, can cut down the cost of pipe equipment and mould, and can get any big diameter and wall thickness is relatively thin carbon steel elbow. 3, due to the above two reasons, can shorten the manufacturing cycle, the production cost greatly reduced. Because do not need any special equipment, especially suitable for machining of carbon steel in site the size of the head. Carbon steel elbow welding first a cross section of a polygon or both ends closed multi multi ring shell fan shell, internal filled with medium pressure, with inner pressure and internal pressure under the action of cross section of polygonal gradually became round, and eventually become a circular ring shell. According to the need of a circular ring shell can be cut into four 90 degree bend or six 60 degree elbow or other specifications of the elbow, the process is suitable for manufacturing elbow pitch diameter and any specifications of large elbow bend diameter ratio greater than 1.5, is the ideal way to make the large carbon steel elbow. Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Bend and elbow the biggest difference is that one is the head, one is the tube. Although this is so, but they are two in the manufacturing process there is a big difference. The most essential difference is that bend is slightly longer than elbow, R=1-2 times is the elbow, and then the big is bend. Manufacturing process on the cold bend will be relative to some simple, you can use the ready-made straight pipe bending, one step can be completed, it does not require the two anti-corrosion. But elbow production is required in accordance with the size of the custom, but also need to do anti-corrosion, long delivery period is relatively long. In the price, bend than elbow to high, then the price will be greater than the bend. But because of the price advantage, bend in the use of the process, compared to some of the more. National west east gas transmission project is the use of 1016*17.5 pipe, elbow used in the position of greater than eleven degrees, less than eleven degrees angle with the bend. Of course, the cost of bend is low. If the cost is to consider a simple elbow, hot bending, cold bend can, so the cost is high elbow. However, be sure to use the elbow in a narrow area in the trench stonework section, the elbow curvature radius is small, mostly 6D, but bend 40D. Elbow is the most notable feature is clean and sanitary, high temperature resistance, anti ultraviolet performance is strong, is a kind of new material with high added value. In which the inner wall of the stamping elbow pipe is smooth, the heat flux is small, and the resistance to acid and alkali, so the service life is long, and it is easy to install. The thermal conductivity of elbow is applied to the floor heating. This kind of pipe is generally required for thermal conductivity and low temperature impact resistance. So that the pipe is not easy to meet the impact of low temperature caused by the rupture of the pipe, but also do not pollute the environment, can be recycled. If you can not be recycled will produce two pollution of the environment. Stamping elbow has a very good long-term pressure performance, only in this regard, the strongest elbow. However, in the influence of various factors, the wall of the pipe floor heating tube is generally two mm thick. This wall thickness requires all pipes to be able to meet, which is difficult to reflect the advantages of bend. Now the general characteristics of the pipe is: carry a strong impact on the performance of strong, smooth surface, long life: in the high temperature or low temperature can have a more prominent softness; Now, the application of bend and elbow is very extensive, so we need to continue to make technology innovation and continuous improvement to meet the needs of consumers. Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)

Stainless steel is not easy to rusty steel, stainless steel in the main alloying element is Cr (chromium), only when the Cr content reaches a certain value, the steel corrosion resistance, stainless steel generally Cr content of at least 10.5%. The corrosion mechanism of stainless steel is the theory of passivation film, that is, its surface to form a layer of very thin and strong and stable stable Cr-rich passivation film to prevent oxygen atoms continue to infiltrate and continue to oxidize, so as to achieve the ability of anti-corrosion. The pattern of passivation film on the surface of stainless steel People think that “stainless steel is not rusty, rusty is not stainless steel.” In fact, this is a lack of understanding of stainless steel a one-sided view of the wrong, stainless steel under certain conditions will rust. If we can intuitively understand the various types of corrosion of stainless steel, the face of stainless steel corrosion can have a corresponding response to reduce the loss. The following describes the actual types of stainless steel common corrosion, a brief introduction to the corresponding anti-corrosion measures, and focus on stainless steel stress corrosion causes and prevention measures. Corrosion damage from stainless steel is mostly local corrosion damage, the most common intergranular corrosion (9%), pitting (23%) and stress corrosion (49%). [1] Corrosion types of stainless steel Intergranular corrosion Intergranular corrosion is due to impoverishment on the grain boundary, leading to preferential corrosion of the region, and thus the overall separation of the grain from the metal. Heat treatment 450 ℃ ~ 850 ℃ temperature range C and Cr easy to form carbon chromium compounds (Cr23C6), the grain boundary consumption of Cr can not be added from the grain in time, so that the grain boundary area of poor Cr, which is caused by intergranular corrosion The essential. For example: a company synthetic ammonia plant furnace gas preheat tube due to intergranular corrosion caused by cracking, leakage occurred. The intergranular corrosion of the preheat tube is due to the precipitation of Cr23C6 in the grain boundary of the austenitic stainless steel, and the intergranular corrosion cracking occurs in the pipe under the action of Cl- in the tube. Microstructure and microstructure of intergranular corrosion In order to prevent intergranular corrosion of stainless steel, the general solution: 1, the solution annealing metal is uniformly heated to 1050 ℃ ~ 1060 ℃, and then rapid cooling; 2, adding stabilized elements Ti, Nb, etc .; 3, the choice of low-carbon stainless steel. Pitting Pitting is a very dangerous local corrosion, the occurrence of small holes and then the phenomenon of rapid corrosion, serious can lead to perforation. Pitting the main factors are: 1, Cl- effect, Cl – stainless steel passive film local damage, leading to the site of the first occurrence of corrosion; 2, the temperature impact, the higher the temperature, the faster corrosion; 3, the surface attached to the contaminants to prevent the flow of oxygen. For example, the daily life of stainless steel (201 or 304 stainless steel majority) sinks often pitting phenomenon. If some acidic or salt substances in the sink did not get timely treatment, it will lead to pitting corrosion of stainless steel sink. Pitting corrosion phenomenon of stainless steel pipe The precautions are as follows: 1, to prevent Cl – attachment; 2, a reasonable surface treatment, the formation of stable passivation film; 3, select the resistance to Cl-corrosive materials (such as the addition of Mo 316L stainless steel). Stress corrosion Stress corrosion refers to the damage caused by the metal in the corrosive medium under the action of tensile stress. The stress corrosion of stainless steel is the most serious corrosive form in the failure of stainless steel. If there is a slight crack in the process of corrosion, the expansion rate is several orders of magnitude faster than other types of corrosion, causing catastrophic consequences. Chemical plants, nuclear power plants, boilers and other stainless steel materials have appeared stress corrosion cracking phenomenon. For example, ① a pharmaceutical enterprise hydroxyl acetonitrile synthesis of glycine project synthesis section to the concentrated section of the 316L stainless steel pipe to the weld occurred a serious stress corrosion cracking. The stress corrosion cracking in the accident originated from the weld defect, the intergranular corrosion occurred improperly in the heat treatment control of the welding process, and the residual stress in the welding resulted in the formation of stress corrosion cracking on the basis of intergranular corrosion. 316L pipe fittings with stress corrosion cracking (2) The reactor reactor core is 304NG stainless steel in the reactor core of the reactor, and the Irradiation Assisted Stress Corrosion Cracking (IASCC) phenomenon occurs in the high temperature and high pressure and strong irradiated water environment. Strict control of the nuclear plant service environment is one of the most effective ways to solve the problem. Irradiation Assisted Stress Corrosion Cracking (IASCC) The study of stress corrosion experiments is based on stress corrosion characteristics and experimental purposes under different conditions. According to the material, environment, stress state and experimental purposes, has developed a variety of stress corrosion test method. Experiments were carried out according to experimental site and environmental quality, laboratory experiment and laboratory accelerated experiment. The experiment was carried out according to the loading method, constant deformation experiment and constant strain rate tensile test. Samples of the same stress corrosion test are generally pided into three categories: smooth specimens, notched specimens and prefabricated crack specimens. CT samples of cracks The stress corrosion problem of stainless steel has been extensively studied, and many different mechanisms have been put forward to explain the stress corrosion phenomenon, but there is no universally accepted mechanism. Because stress corrosion is a process related to corrosion, the mechanism must be related to the anode and cathode reactions in the process of corrosion. Therefore, the stress corrosion mechanism is mainly pided into two categories: anodic dissolution and hydrogen cracking, and in these two mechanisms Based on the development of the surface membrane rupture theory, active channel theory, stress adsorption cracking theory, corrosion product wedge theory and occlusion battery theory. Theoretical model of surface film rupture Factors Affect Stress Corrosion There are three main factors: material, corrosion environment and tensile stress. The material factors include element content, heat treatment, microstructure and surface state. The corrosion environment includes medium type, temperature, potential and liquid flow rate. The tensile stress includes service stress, installation stress, residual stress and tensile rate. Solution: 1, to reduce the stress concentration of high stress components; 2, to prevent the introduction of chloride ions; 3, to avoid stress processing; 4, heat treatment, to eliminate stress; 5, the use of resistant SCC ferrite stainless steel; 6, the use of high-Ni steel In the new era of rapid progress in science and technology and continuous improvement of scientific research level, the research and development speed of new materials still can not keep up with the speed of the problem. In the practical engineering application of stainless steel corrosion problems emerge in an endless stream, although the current protective measures have achieved some success, but there are still serious shortcomings, a variety of means of protection can only play a role in a certain range. Reasonable selection, real-time detection is still the key to control corrosion.

304 stainless steel pipe is produced according to the United States ASTM standard stainless steel brand. 304 stainless steel pipe is equivalent to China’s 0Cr19Ni9 (0Cr18Ni9) stainless steel pipe. 304 stainless steel pipe classification there are many, the first is seamless pipe and straight seam welded steel pipe, the most basic classification is 304 stainless steel pipe and industrial fluid delivery with 304 stainless steel pipe. It is a versatile stainless steel pipe that is widely used to produce equipment and machines that require good overall performance (corrosion resistance and formability). For example: food production equipment, the former chemical equipment, nuclear energy and so on. Grade specifications for 304 grade stainless steel Grade UNS No Old British Euronorm Swedish SS Japanese JIS BS En No Name 304 S30400 304S31 58E 1.4301 X5CrNi18-10 2332 SUS 304 Typical Chemical Composition % (max values, unless noted) Weight % C Mn P S Si Cr Ni 304 .08 2.00 .045 .030 1.00 18.0-20.0 8.0-11.0 Typical Mechanical Properties Grade Tensile Ultimate/Min Yield/Min Elongation/Min KSI MPA KSI MPA % 304 75 515 30 205 35 Physical properties of 304 grade stainless steel in the annealed condition Grade Density (kg/m3) Elastic Modulus (GPa) Mean Coefficient of Thermal Expansion (μm/m/°C) Thermal Conductivity (W/m.K) Specific Heat 0-100°C (J/kg.K) Electrical Resistivity (nΩ.m) 0-100°C 0-315°C 0-538°C at 100°C at 500°C 304/L/H 8000 193 17.2 17.8 18.4 16.2 21.5 500 720 304 stainless steel pipe anti-intergranular corrosion performance is good, with excellent corrosion resistance and cold processing, stamping performance, can be used as a heat-resistant stainless steel. At the same time, the steel at -180 ℃under the conditions of its mechanical properties are still good. In the solid solution state of steel plasticity, toughness, cold workability in the oxidizing acid and atmospheric, water and other medium corrosion resistance, therefore, it is the most widely used steel. 304 stainless steel pipe tolerances: NPS Designator Permissible Variations in Outside Diameter​ Over In. Under In. 1/8 to 1-1/2, incl 1/64 (0.015) 1/32 (0.031) Over 1-1/2 to 4, incl 1/32 (0.031) 1/32 (0.031) Over 4 to 8, incl 1/16 (0.062) 1/32 (0.031) Over 8 to 18, incl 3/23 (0.093) 1/32 (0.031) ​ Minimum Wall Thickness on Inspection: tn * 0.875 = tm Where: tn = nominal wall thickness, in. [mm], and tm= minimum wall thicknesses, in. [mm] The wall thickness is inch-pound units is rounded to three decimal places in accordance with the rounding method of Practice E29. The wall thickness in SI units is rounded to one decimal place in accordance with the rounding method of Practice E29. · This table is a master table covering wall thicknesses available in the purchase of different classifications of pipe, but it is not meant to imply that all the walls listed herein are necessarily obtainable for the applicable product specification. Nominal Thickness Minimum Thickness on Inspection Nominal Thickness Minimum Thickness on Inspection Nominal Thickness Minimum Thickness on Inspection in. mm in mm in mm in mm in mm in mm 0.068 1.7 0.060 1.5 0.294 7.5 0.257 6.5 0.750 19.0 0.658 16.6 0.068 2.2 0.077 2.0 0.300 7.6 0.262 6.7 0.812 20.6 0.710 18.0 0.091 2.3 0.080 2.0 0.307 7.8 0.269 6.8 0.843 21.4 0.736 18.7 0.095 2.4 0.083 2.1 0.308 7.8 0.270 6.9 0.854 21.7 0.756 19.2 0.113 2.9 0.099 2.5 0.312 7.9 0.273 6.9 0.875 22.2 0.766 19.5 0.119 3.0 0.104 2.6 0.318 8.1 0.278 7.1 0.906 23.0 0.783 20.1 304 stainless steel pipe’s theory weight calculation formula: (diameter – wall thickness) × wall thickness × 0.02491 = weight per meter (kg) Corrosion Resistance Excellent in a wide range of atmospheric environments and many corrosive media. Subject to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above about 60°C. Considered resistant to potable water with up to about 200mg/L chlorides at ambient temperatures, reducing to about 150mg/L at 60°C. Heat Resistance Good oxidation resistance in intermittent service to 870°C and in continuous service to 925°C. Continuous use of 304 in the 425-860°C range is not recommended if subsequent aqueous corrosion resistance is important. Grade 304L is more resistant to carbide precipitation and can be heated into the above temperature range. Grade 304H has higher strength at elevated temperatures so is often used for structural and pressure-containing applications at temperatures above about 500°C and up to about 800°C. 304H will become sensitised in the temperature range of 425-860°C; this is not a problem for high temperature applications, but will result in reduced aqueous corrosion resistance. Heat Treatment Solution Treatment (Annealing) – Heat to 1010-1120°C and cool rapidly. These grades cannot be hardened by thermal treatment. Welding Excellent weldability by all standard fusion methods, both with and without filler metals. AS 1554.6 pre-qualifies welding of 304 with Grade 308 and 304L with 308L rods or electrodes (and with their high silicon equivalents). Heavy welded sections in Grade 304 may require post-weld annealing for maximum corrosion resistance. This is not required for Grade 304L. Grade 321 may also be used as an alternative to 304 if heavy section welding is required and post-weld heat treatment is not possible. Machining A “Ugima” improved machinability version of grade 304 is available in bar products. “Ugima” machines significantly better than standard 304 or 304L, giving higher machining rates and lower tool wear in many operations. Dual Certification It is common for 304 and 304L to be stocked in “Dual Certified” form, particularly in plate and pipe. These items have chemical and mechanical properties complying with both 304 and 304L specifications. Such dual certified product does not meet 304H specifications and may be unacceptable for high temperature applications. Applications Typical applications include: · Food processing equipment, particularly in beer brewing, milk processing & wine making. · Kitchen benches, sinks, troughs, equipment and appliances · Architectural panelling, railings & trim · Chemical containers, including for transport · Heat Exchangers · Woven or welded screens for mining, quarrying & water filtration · Threaded fasteners · Springs Source: wilsonpipeline Pipe Industry Co., Limited (www.wilsonpipeline.com)​