The delayed fracture behaviors of CrMo-type high strength steels containing different amount of titanium(0to 0.10%)were studied.The steels were quenched at 880℃ and tempered from 400℃ to 650℃,and a wide range of te...The delayed fracture behaviors of CrMo-type high strength steels containing different amount of titanium(0to 0.10%)were studied.The steels were quenched at 880℃ and tempered from 400℃ to 650℃,and a wide range of tensile strength was obtained.The sustained load tensile test was carried out by using notched tensile specimens in Walpole solution.The experimental results showed that with higher strength,the Ti-microalloyed steels show higher resistance to delayed fracture compared with non-microalloyed steel due to titanium beneficial role and microstructure changes.The undissolved TiC is uniformly distributed as strong hydrogen traps,retarding or preventing the diffusion and accumulation of hydrogen to lower-interaction energy sites,such as prior austenite and martensite lath boundaries in stress concentration area.Meanwhile,the grain refining effect of titanium is also an important factor to improve the delayed fracture resistance of Ti-microalloyed steels.The characteristics of delayed fracture remain nearly the same with titanium addition.展开更多
The netlike eutectic carbide in twin roll casting strip of W9Cr4V2 was dissolved and broken up gradually with increasing heating temperature during annealing treatment. Almost all eutectic carbides exist in granular ...The netlike eutectic carbide in twin roll casting strip of W9Cr4V2 was dissolved and broken up gradually with increasing heating temperature during annealing treatment. Almost all eutectic carbides exist in granular form with heating temperature up to 950 ℃. It is considered that the refining of lamellar spacing made it possible for eutectic carbide to be granulated.展开更多
基金Item Sponsored by National Key Fundamental Research and Development Project of China(G1998061503)National Science and Technology Development Project of China(2002BA314B08)
文摘The delayed fracture behaviors of CrMo-type high strength steels containing different amount of titanium(0to 0.10%)were studied.The steels were quenched at 880℃ and tempered from 400℃ to 650℃,and a wide range of tensile strength was obtained.The sustained load tensile test was carried out by using notched tensile specimens in Walpole solution.The experimental results showed that with higher strength,the Ti-microalloyed steels show higher resistance to delayed fracture compared with non-microalloyed steel due to titanium beneficial role and microstructure changes.The undissolved TiC is uniformly distributed as strong hydrogen traps,retarding or preventing the diffusion and accumulation of hydrogen to lower-interaction energy sites,such as prior austenite and martensite lath boundaries in stress concentration area.Meanwhile,the grain refining effect of titanium is also an important factor to improve the delayed fracture resistance of Ti-microalloyed steels.The characteristics of delayed fracture remain nearly the same with titanium addition.
基金Item Sponsored by National Key Fundamental Research Development Project of China(G1998061503)
文摘The netlike eutectic carbide in twin roll casting strip of W9Cr4V2 was dissolved and broken up gradually with increasing heating temperature during annealing treatment. Almost all eutectic carbides exist in granular form with heating temperature up to 950 ℃. It is considered that the refining of lamellar spacing made it possible for eutectic carbide to be granulated.