Stress corrosion cracking (SCC) refers to the cracking caused by the combined action of stress corrosion stress (mainly tensile stress) and corrosion of austenitic stainless steel Austenitic stainless steel is prone to stress corrosion in corrosive media containing chloride ions. When the Ni content reaches % - %, it is a long-term enterprise engaged in stainless steel plate, stainless steel coil, stainless steel belt and stainless steel pipe. Welcome to consult. The stress corrosion tendency of austenitic stainless steel is very large. Continue to increase the Ni content to ~ %, and the stress corrosion tendency gradually decreases until it disappears.Assembly: the sealing ring shall be correctly installed in the U-groove of the pipe fitting, put the pipe into the socket of the pipe fitting and wait for crimping.Merdrin,Steady state creep accelerated oxidation of stainless steel pipe during low cycle fatigue test in air environment. Obvious oxidation will occur in stainless steel pipe. Previous studies have shown that the time required for oxygen in air to diffuse to the fatigue crack tip is about the order of magnitude, and the biochemical reaction time between oxygen and fresh metal is longer than that of oxygen, about . seconds, which leads to high temperature air When the low cycle fatigue test is carried out in the gas environment, the oxygen content at the fatigue crack tip of the stainless steel pipe sample is always saturated, and the excess oxygen can diffuse to the base resulting in the weakening of the bonding of the base metal atoms, increasing the embrittlement tendency of the material, and accelerating the expansion and growth of the crack. At the same time of low cycle fatigue, high temperature will also cause creep deformation of the stainless steel pipe, High temperature provides additional energy for the accelerated diffusion of atoms. When there are defects in the material, such as holes and voids, the atomic diffusion becomes easy, and with the progress of low cycle fatigue, dislocations will be generated in the material. Under the action of stress, the slip and climb of dislocations interact with point defects to promote the aggregation of micropores and form large voids, such as holes and voids Surrounding atomThe back side is not protected by argon, and the flux coated welding wire (self protective flux cored welding wire) + TIG process is adopted. In the s, China has also developed the stainless steel backing welding wire (i.e. flux coated welding wire, such as tgftgftgftgf, etc.) It has been applied to the actual construction and achieved good results. We have successfully applied it in the capacity expansion and reconstruction project of Urumqi Petrochemical.Harar,In order to ensure the appearance quality of continuous casting slab, select appropriate maintenance slag; During continuous casting, the vibration marks formed on the surface of continuous casting slab due to the vibration of mold shall be; Electromagnetic stirring must be used in continuous casting of ferritic stainless steel pipe fittings.Add a small amount of sulfur and phosphorus to make it easier to cut.Stainless steel grade group Series & mdash; Chromium nickel manganese austenitic stainless steel series & mdash; Chromium nickel austenitic stainless steel model & mdash; Good ductility, such as high strength, good corrosion resistance, strong impact resistance and so on, which makes it widely used in various fields of life. With the continuous improvement of automation, people have higher and higher requirements for the cutting quality of stainless steel pipe. At present, there are still many deficiencies in pipe cutting in China, which seriously restricts China's industrial development. Therefore, recently, the research on pipe cutting machine with high precision, high automation, high cutting quality and high cutting efficiency has become the research focus and difficulty of relevant disciplines, and it is also the inevitable trend of the further development of China's industry. Firstly, the intermittent cutting method of planetary bisymmetric eccentric installation can reduce the cutting deformation of stainless steel pipe and improve the cutting accuracy; Secondly, the tool of the intermittent stainless steel pipe cutting machine is eccentrically installed on the planetary gear to complete the rotation at the same time of revolution. Therefore, only one main motor can drive two tools to rotate. The mechanical structure reduces the use of the motor, improves the use efficiency of the motor and reduces the manufacturing cost of the equipment; Then the main components of the intermittent pipe cutter are analyzed by using SolidWorks D solid software and ANSYS finite element analysis software. ANSYS software verifies the rationality of the structure and improves the service life of the pipe cutter. At present, there are still many deficiencies in pipe cutting in China, which seriously restricts China's industrial development. Therefore, recently, the research on pipe cutting machine with high precision, high automation, high cutting quality and high cutting efficiency has become the research focus and difficulty of relevant disciplines, and it is also the inevitable trend of the further development of China's industry. Firstly, the cutting characteristics of the intermittent stainless steel pipe cutter in the cutting process are analyzed, and the cutting force in the cutting process is calculated. Secondly, the overall cutting scheme of the intermittent stainless steel pipe cutter is determined, the finite element analysis is carried out for the important parts of the intermittent stainless steel pipe cutter, The reliability of its strength and stiffness is verified. In the design process of intermittent stainless steel pipe cutting machine, complete the tasks of scheme determination, theoretical analysis and structural design, and verify the rationality of the structure. This paper aims to design a pipe cutting machine with high automation, compact structure and high cutting precision, so as to improve the cutting quality of stainless steel pipe and bring more economic and social benefits to the enterprise. This paper comprehensively analyzes the research on stainless steel pipe cutting machines at home and abroad, draws lessons from the advanced structural design of relevant foreign pipe cutting machines, and makes a comparative analysis and Research on the characteristics of easy deformation and difficult cutting of stainless steel pipes. Taking the stainless steel pipe with diameter of mm ~ mm and wall thickness of mm ~ mm as the design object, and based on the structure of the existing planetary pipe cutting machine, A planetary double symmetrical eccentric installation intermittent cutting is proposed. The cutting can not only realize its own main motion and feed motion, but also reduce the deformation of stainless steel pipe in the cutting process. Professional L stainless steel pipe, fire resistance excellent quality and low price, water resistance, high temperature resistance strong and durable, and improve the quality of cutting surface.Stainless steel water supply pipe is a healthy safe and reliable, economic, sanitary and energy-saving water pipe. It is the best choice for both domestic and large engineering buildingsArgon shall conform to the rules of national specifications, and argon with purity of % shall be selected. If the content of impurities is too high, the maintenance effect of argon will be weakened and the weld quality will be indirectly affected.Promotion,Stainless steel pipes can be divided into CR series ( Series), Cr Ni series ( Series), Cr Mn Ni series ( Series) and precipitation hardening series ( Series). Series & mdash; Cr Ni Mn austenitic stainless steel series & mdash; Cr Ni austenitic stainless steel.The main way to prevent stress corrosion of austenitic stainless steel is to add SI ~ % and keep the content of N below .% from smelting. In addition, the content of impurities such as P, Sb, Bi and as should be reduced as much as possible. In addition, A-F dual phase steel can be selected, which does not correspond to stress corrosion in Cl - and oh - media. The initial micro crack will not continue to expand after encountering ferrite phase,Merdrin316Ti stainless steel pipe, and the ferrite content should be about % .Rockwell hardness the Rockwell hardness test of stainless steel pipe is the same as Brinell hardness test. The difference is that it measures the depth of indentation. Rockwell hardness test is widely used at present, and HRC is second only to Brinell hardness Hb in steel pipe standards. Rockwell hardness can be used to measure metal materials from very soft to very hard, which makes up for the disadvantage of Brinell method, It is simpler than Brinell method and can read the hardness value directly from the dial of the hardness machine. However, due to its small indentation, the hardness value is not as accurate as Brinell method.

Hardness test: annealed stainless steel pipes with inner diameter of more than mm and wall thickness of less than mm can be tested by w-b Vickers hardness tester, which is very fast and simple, and is suitable for rapid and nondestructive qualification test of stainless steel pipes. For stainless steel pipes with inner diameter of more than mm and wall thickness of more than mm Rockwell hardness tester shall be used to test HRC hardness. Stainless steel pipes For stainless steel pipes with inner diameter greater than mm and wall thickness less than mm, the surface Rockwell hardness tester shall be used to test HRT or hrn hardness. For stainless steel pipes with inner diameter less than mm and greater than mm, the special Rockwell hardness tester for pipes shall be used to test hrt hardness. When the inner diameter of stainless steel pipes is greater than mm, the Rockwell or surface Rockwell hardness tester can also be used to test the hardness of pipes.Design brand,The selection of pipes and fittings for welding data preparation shall be based on the quality elements of the application environment, chemical composition and application pressure,Merdrin20 large diameter seamless steel pipe, and the commodities of corresponding grades shall be selected to ensure the weld metal structure and machine function.cm thick stainless steel plate shall be processed with special cutting tools,Only soluble paper or the combination of soluble paper and blocking plate is used for blocking ventilation protection (i.e. solid core welding wire + TIG + water-soluble paper)Proper heat treatment process can prevent intergranular corrosion and obtain excellent corrosion resistance.. Raw material problem of stainless steel pipe. If the hardness is too low, it is not easy to polish (BQ is not good). If the hardness is too low, orange peel is easy to appear on the surface during deep drawing, which affects BQ performance. BQ with high hardness is relatively good.