Effects Of Heat Treatment Process On Microstructure And Properties Of Cr13-type Stainless Steel

Based on the key research program of Great Wall Special Steel Corp (simplified GWSSC), taking the sectional bars of 1Cr13 , 2Cr13,3Cr13 produced by the rolling mill II of GWSSC , investigate the influence of heat treatment on microstructure and properties of steel .Furthermore discuss the on-line heat treatment process scheme of Crl3-type stainless steel considering manufacture demand.The results showed as follow :(1) Three kinds of stainless steels such as 1Cr13, 2Cr13 and 3Cr13 have the basic same metallurgical structures after quenching and tempering in the same condition, troostitic structures emerge after tempering in 400~550℃, perlite structures emerge after tempering in 750 ℃ .The cementite phases still increase with the increase of carbon content.(2) With the increase of carbon content, the temper hardness of Cr13-type stainless steel increases and the temper ductility descends correspondingly.(3) The hardness of Cr13-type stainless steel increases relevantly with the increase of tempering temperature after quenching and tempering, and maximize at 500 ~ 510℃.When tempering temperature further heightens, he hardness descends gradually.(4) With the equal quenching of Cr13-type stainless steel, temper ductility at 300~ 500℃ shows a slight decrease with the increase of tempering temperature; temper ductility emerges minimum values at 500~540℃ because of the effects of temper brittleness; and at 540~750℃ temper ductility shows a slight increase with the increase of tempering temperature due to the extinction of temper brittleness.(5) According to different service condition, when considering the optimal strength-ductility matched request demanded by steel, tempering at 500~540℃ should be avoided, it also must pay attention to the choose of tempering interval not only for one index such as strength or ductility. For example, to the steel serviced at hypothermia, when considering the optimal strength-ductility matched, it is more consideration to hypothermia dynamic ductility, that is to say, it can increase properly tempering temperature to 660 ℃ or even higher.(6) On the one hand, furnace temperature must be uniform and stability in the process of on-line heat treatment when Crl3-type stainless steel was produced. On the other hand, the influence of temper brittleness must be considered. The quick cooling after temper is the best way to eliminating the brittleness of the second kind.