The effects of shielding gas and post weld heat treatment on the pitting resistance, stress corrosion crack- ing and hydrogen embrittlement of supermartensitic stainless steel deposits were studied. Two all-weld-metal...The effects of shielding gas and post weld heat treatment on the pitting resistance, stress corrosion crack- ing and hydrogen embrittlement of supermartensitic stainless steel deposits were studied. Two all-weld-metal test coupons were prepared using a metal-cored wire under Ar＋ 5% He and Ar＋18%CO2 gas shielding mixtures. Solubi- lizing and solubilizing plus double tempering heat treatments were done with the objective of achieving different mi crostructural results, The samples welded under Ar＋5% He showed higher pitting corrosion resistance, for all post weld heat treatments, than those welded under Ar＋18% CO2. The different post weld heat treatments generated higher susceptibility to this corrosion mechanism. None of the samples presented signs of stress corrosion cracking, but in those subjected to the heat treatment, grain boundary selective attack was observed, on the surfaces of all the samples studied. The samples with highest hardness were more susceptible to hydrogen damage, thereby leading to reduced tensile strength on this condition.展开更多
The effect of hydrogen addition on compression deformation behaviour of Ti-0.3Mo-0.8Ni alloy argon-arc welded joint has been investigated.Evolution mechanism of hydrogen-induced flow stress was discussed in detail.The...The effect of hydrogen addition on compression deformation behaviour of Ti-0.3Mo-0.8Ni alloy argon-arc welded joint has been investigated.Evolution mechanism of hydrogen-induced flow stress was discussed in detail.The results show that with increasing hydrogen content,the stretching and bending extent of fully lamellar microstructures including ot lamellas and acicular hydride continued to increase,the morphology of dynamic recrystallization(DRX)grains tended to change from approximately equiaxed to large lamellar shape,and the quantity of DRX grains and recrystallization degree of grains increased obviously.A large number of dislocations concentrated in the vicinity of the hydride.Steady stress was decreased continuously with increasing hydrogen content,while peak stress of the hydrogenated 0.12 wt.% H weld zone was decreased to the minimum value and then increased slowly.A slight decrease in flow stress of the hydrogenated 0.05 wt.% H weld zone was caused by limited increase in the volume fraction of softer βphase.Hydrogen-induced DRX of a phase and improved dislocation movement by strong interaction between the hydride and dislocation directly resulted in a sharp drop in flow stress of the hydrogenated 0.12 and 0.21 wt.% H weld zone.Solute hydrogen also finitely contributed to a sharp drop in flow stress of the hydrogenated 0.12 and 0.21 wt.% H weld zone by promoted local softening,which induced continuous DRX and more movable dislocations to participate in slipping or climbing.The reinforcement effect and plastic deformation of the hydride and solution strengthening of P phase induced by solute hydrogen finally led to the increase in flow stress of the hydrogenated 0.21 wt.% H weld zone in its true strain range from 0 to 0.36.展开更多
Thispaperintroduces materialandstructureofthe hydrogenation reactors, and analysesthe problems presentin use of hydrogenation reactors. Main factors which can lead to stoppingworkof reactors, are hydrogen attack, hyd...Thispaperintroduces materialandstructureofthe hydrogenation reactors, and analysesthe problems presentin use of hydrogenation reactors. Main factors which can lead to stoppingworkof reactors, are hydrogen attack, hydrogen embrittlement, temper embrittlement andstripsof overlap weldinglayer,andsomeproposalsare putforward forsafeoperation ofre actors. Finallyitissuggested thatitbe notenough only by advancing the reactor material,and adoptingthe new design and structureof reactorisimperative.展开更多
基金APUEMFI,Argentina and ANPCyT,Argentina for financial support
文摘The effects of shielding gas and post weld heat treatment on the pitting resistance, stress corrosion crack- ing and hydrogen embrittlement of supermartensitic stainless steel deposits were studied. Two all-weld-metal test coupons were prepared using a metal-cored wire under Ar＋ 5% He and Ar＋18%CO2 gas shielding mixtures. Solubi- lizing and solubilizing plus double tempering heat treatments were done with the objective of achieving different mi crostructural results, The samples welded under Ar＋5% He showed higher pitting corrosion resistance, for all post weld heat treatments, than those welded under Ar＋18% CO2. The different post weld heat treatments generated higher susceptibility to this corrosion mechanism. None of the samples presented signs of stress corrosion cracking, but in those subjected to the heat treatment, grain boundary selective attack was observed, on the surfaces of all the samples studied. The samples with highest hardness were more susceptible to hydrogen damage, thereby leading to reduced tensile strength on this condition.
基金The authors would like to gratefully acknowledge that this work was supported by the China Postdoctoral Science Foundation(Grant No.2020M672306)National Natural Science Foundation of China(Grant Nos.51874225 and 51671152).
文摘The effect of hydrogen addition on compression deformation behaviour of Ti-0.3Mo-0.8Ni alloy argon-arc welded joint has been investigated.Evolution mechanism of hydrogen-induced flow stress was discussed in detail.The results show that with increasing hydrogen content,the stretching and bending extent of fully lamellar microstructures including ot lamellas and acicular hydride continued to increase,the morphology of dynamic recrystallization(DRX)grains tended to change from approximately equiaxed to large lamellar shape,and the quantity of DRX grains and recrystallization degree of grains increased obviously.A large number of dislocations concentrated in the vicinity of the hydride.Steady stress was decreased continuously with increasing hydrogen content,while peak stress of the hydrogenated 0.12 wt.% H weld zone was decreased to the minimum value and then increased slowly.A slight decrease in flow stress of the hydrogenated 0.05 wt.% H weld zone was caused by limited increase in the volume fraction of softer βphase.Hydrogen-induced DRX of a phase and improved dislocation movement by strong interaction between the hydride and dislocation directly resulted in a sharp drop in flow stress of the hydrogenated 0.12 and 0.21 wt.% H weld zone.Solute hydrogen also finitely contributed to a sharp drop in flow stress of the hydrogenated 0.12 and 0.21 wt.% H weld zone by promoted local softening,which induced continuous DRX and more movable dislocations to participate in slipping or climbing.The reinforcement effect and plastic deformation of the hydride and solution strengthening of P phase induced by solute hydrogen finally led to the increase in flow stress of the hydrogenated 0.21 wt.% H weld zone in its true strain range from 0 to 0.36.
文摘Thispaperintroduces materialandstructureofthe hydrogenation reactors, and analysesthe problems presentin use of hydrogenation reactors. Main factors which can lead to stoppingworkof reactors, are hydrogen attack, hydrogen embrittlement, temper embrittlement andstripsof overlap weldinglayer,andsomeproposalsare putforward forsafeoperation ofre actors. Finallyitissuggested thatitbe notenough only by advancing the reactor material,and adoptingthe new design and structureof reactorisimperative.
