Effect of residual stress and hardening on grain boundary sliding in welds of low-carbon stainless steels with surface machining

Mori, Hiroaki*; Katsuyama, Jinya; Mochizuki, Masahito*; Nishimoto, Kazutoshi*

Hozengaku, 7(1), p.36 - 41, 2008/04

http://ci.nii.ac.jp/naid/40015989128

To clarify the effects of residual stress and hardening on intergranular stress corrosion cracking (IGSCC) behavior in welds of low-carbon austenitic stainless steels with surface machining, residual stress and hardness were evaluated by 3-dimentional thermo elastic-plastic analysis and grain boundary sliding behavior was examined using a constant strain rate tensile test. It was revealed that grain boundary sliding occurred in the material at 561 K by the tensile test with the numerically simulated tensile residual stress due to welding and surface machining. In addition, it was clarified that the grain boundary energy is raised by the grain boundary sliding. On the basis of these results, it was concluded that the cause of IGSCC in the welds of low-carbon austenitic stainless steel with surface hardening is the increase in grain boundary energy due to grain boundary sliding accelerated by residual stress of multi pass welding and surface hardening.

Study on the mechanism of intergranular stress corrosion cracking and analysis of residual stress and work hardening in welds of low-carbon austenitic stainless steel with hard surface machining

Mori, Hiroaki*; Katsuyama, Jinya; Mochizuki, Masahito*; Nishimoto, Kazutoshi*; Toyoda, Masao*

Corrosion Engineering, 56(12), p.757 - 770, 2007/09

In order to clarify the effects of residual stress and hardening on intergranular stress corrosion cracking (IGSCC) behavior in the welds of Type 316L stainless steel with surface hardening, the residual stress and hardness in the butt joint of pipes were estimated and grain boundary sliding was analyzed from the viewpoint of microdeformation. The residual stress and hardness in hard-machined surfaces near welds was clarified from experiment and analysis method. Grain boundary sliding in the cold-rolled specimen occurs in smaller strain conditions than that in as-received specimen; the amount of grain boundary sliding increases remarkably with an increase in rolling reduction. We also clarified that grain boundary energy is raised by grain boundary sliding. On the basis of the results, we concluded that the cause of IGSCC in the welds of Type 316L stainless steel with surface hardening is the increase in grain boundary energy induced by residual stress of welding and surface hardening.

Corrosion Resistance of Titanium for Nuclear Waste Container in Non-oxidizing Condition (II)

Wada, Ryutaro*; Nishimura, Tsutomu*; Shimogori, Kazutoshi*; Tomari, Haruo*; Masugata, Tsuyoshi*; Shimoda, Hideaki*; Fujiwara, Kazuo*; Nishimoto, Hidetoshi*; Oda, Masashi*

PNC TJ1058 98-001, 446 Pages, 1998/02

PNC-TJ1058-98-001.pdf:36.59MB

None

Technical issues of welding of reduced activation ferritic/martensitic steels at the fabrication of ITER test blanket module

Tanigawa, Hiroyasu; Ogiwara, Hiroyuki; Hirose, Takanori; Shiba, Kiyoyuki; Serizawa, Hisashi*; Kawahito, Yosuke*; Tanaka, Manabu*; Katayama, Seiji*; Mori, Hiroaki*; Nishimoto, Kazutoshi*

no journal, , 

Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems. These steels have been developed based on substantial industrial experience with high chromium heat resistant ferritic/martensitic steels (such as modified 9Cr-1Mo), but with Mo and Nb replaced by W and Ta, respectively. The objective of this paper is to review the R&D status of F82H and to identify the key technical issues for the fabrication of an ITER Test Blanket Module (TBM) suggested by recent achievements in Japan.