Jilin hydrogen stripping test
Tianjin Rong Da Testing Co., Ltd. contact: Wang Jingfu
Cell phone: 13102238283 QQ:3144667033
Telephone: 022-23892103
Hydrogen stripping: due to austenitic stainless steel making reactor body material Cr-Mo steel and welding layer with different hydrogen solubility and diffusion process, resulting in the use of high concentrations of hydrogen in the surfacing layer transition zone side, because the base metal and welding material layer of linear expansion coefficient difference caused by interface there is considerable residual stress; effect of metallurgical factors of surfacing layer at the interface with (due to manufacturing heat treatment after welding, the boundary layer by carbide precipitation and may influence the formation of coarse crystalline fusion along the layer growth etc.) caused by peeling.
Hydrogen stripping standard: G146-2001 ASTM (2013), cycle for 15 days
ASTM G146-01 on the hot wall hydrogenation reactor of surfacing layer and the substrate resistance to hydrogen induced disbonding properties test method and test procedure based on sample size determination, including heat treatment, ultrasonic testing, cleaning, degassing, pressure test, hydrogen charging, block cutting, metallographic examination etc..
After a certain period of time, the hot wall hydrogenation reactor is used to detect the phenomenon of the separation of the main part of the surfacing layer, which is called the delamination of the surfacing layer.
Causes of peeling occurs, the more consistent view is: the operation of the absorbed hydrogen at high temperature and high pressure in the shutdown cooling process will accumulate in the substrate and the cladding layer interface (coarse microstructure of the interface and the associated part of sigma phase or martensite), higher hydrogen concentration. In addition, the thermal expansion coefficient of the substrate and the surfacing layer is large, and the thermal stress is relatively large. The combined action of hydrogen and stress is easily induced by stripping. The reactor at the interface between substrate and cladding layer peeling phenomenon, is also a kind of essence of hydrogen embrittlement (hydrogen induced cracking), macro is development along the grain boundary layer, belonging to two different materials in the grain boundary due to residual hydrogen caused by hydrogen embrittlement cracking. There are many factors that affect the anti stripping performance, and many of the mechanisms are still being explored. Therefore, the experimental research is a key direction at home and abroad.