Heat treatment and tissue properties of the alloy hardened steel heat treatment are generally direct quenching after carburizing, and then tempering. 60mn steel after heat treatment, the tissue surface carburized layer alloy cementite + tempered martensite + 30 small amount of residual austenite manganese steel, hardness 60HRC ~ 62HRC. Heart tissue and hardenability and steel parts cross-sectional dimension is related to low-carbon hardenability completely when tempered martensite, hardness 40HRC ~ 48HRC; in most cases troostite, tempered martensite and a small amount of iron ferrite hardness 25HRC ~ 40HRC. Heart toughness are generally higher than 700KJ / m2. Low alloy structural steel is made of low-alloy structural steel hot-rolled. Low-alloy steel plate were killed steel and semi-killed steel plate. Its advantages are high strength, performance than the more, can save a lot of steel, reduce the structural weight and so on. (1) The main purpose of low-alloy structural steel is widely used in machinery manufacturing and metal structural parts. (2) Material grades, chemical composition of steel category See related section. (3) hot-rolled steel sheet thickness Size of 4.5-200mm. 4mm steel | Fair Commerce Bo | sheet provided by the Hefei exhibition Bo Trading Company. 4mm steel | Fair Commerce Bo | sheet Hefei Show Bo Trading Company (www.hfzhanbo.com) (www.hfzhanbo.com) this year introduced a new upgrade, the above picture is for reference only, please call or pictures on this page contact telephone number, to obtain the latest information, contact: Mr. Huang.