Ferrite test standard
Tianjin Rong Da Testing Co., Ltd. contact: Wang Jingfu
Cell phone: 13102238283 QQ:3144667033
Telephone: 022-23892103
Petroleum, chemical, nuclear power, light industry, medicine and other departments, a large number of pressure vessels, pipelines, components and valves, etc., are made of austenitic stainless steel welding. Such as stainless steel clad welding, stainless steel welding, dual phase stainless steel welding, etc.. Therefore, the austenitic stainless steel welding technology welding crack, the corrosion resistance of welded joints, welding and deposited metal embrittlement problem has become the key to affect the performance and life of the product.
Ferrite content test standard austenitic stainless steel usually contain a certain amount of ferrite (15% ~ 5%). Ferrite has double function, a certain number of austenitic stainless steel and its weld metal in the ferrite (5% ~ 15%) to prevent welding hot crack, improve the resistance to intergranular corrosion and stress corrosion ability plays a very important role at the same time, a certain number of weld, casting the ferrite content (5% ~ 20%) to prevent thermal cracks, improve the mechanical properties of castings are favorable. In some specific environments, such as high temperature, low temperature, and selective corrosion environment, the adverse effects should be controlled. Therefore, to study the effect of austenite ferrite, ferrite master control principle and method of measurement and calculation, the research and development of high parameter stainless steel valves, especially the design and manufacture of nuclear safety grade stainless steel valves, has very important significance.
In general, the welding of stainless steel vessels with different media is required to control different ferrite content.
Because the welding performance (crack sensitivity), requirement of ferrite content is more than 5%Fe as well, from the angle in the general corrosion resistance, medium ferrite content is more than 8%Fe as well; but in the medium, such as urea, with less than 0.5%Fe as well; from the view of mechanical performance, especially in the weld under high temperature, which is less than 5%Fe is appropriate, or it will produce sigma phase embrittlement. It can be seen that the stainless steel welding production and scientific research work, both need to be convenient and accurate control and measurement of the weld or deposited metal ferrite content