NIMS Develops 1,500MPa Alloy Steel with High Impact Strength

Japanese official research organization for metals and other materials, National Institute for Materials Science (NIMS) announced on Monday it developed low alloyed steel with 1,500 mega pascal of tension strength and better performance against impact strength. NIMS succeeded to develop the material by using original heat treatment technology. The new steel paves the way for making high tensile steel bar with flexibility as wood. NIMS expects the technology could enable to make super high tensile steel bolt and shaft with 2,000 MPa strength. NIMS holds presentation for the technology at autumn conference held by Iron and Steel Institute of Japan from September 19. Traditional low alloyed spring steel with more than 1,300 MPa of strength has 30-40 joule of impact absorption and such materials cannot be used for structural parts due to the low toughness. NIMS succeeded to make super fine fiber type crystal grain with around 0.4 micrometers of grain diameter through the heat treatment process for tempering martensite phase of alloy with 0.6% carbon, 2% silicon and 1% chrome. The new steel with tensile strength, ductility and toughness has averaged 165 joule of impact absorption. NIMS expects the heat treatment technology can be applied to certain materials, which were hard for cold finishing process. NIMS tries to develop technology to make complicated shapes as shaft and bolt through ongoing test for delayed cracking and fatigue failure and trials for efficient production process.