回火温度对一种Fe-Cr-Ni-Mo高强钢碳化物及其力学性能的影响  

EFFECT OF TEMPERING TEMPERATURE ON CARBIDE AND MECHANICAL PROPERTIES IN A Fe-Cr-Ni-Mo HIGH-STRENGTH STEEL

作　　者：温涛[1] 胡小锋[1] 宋元元[1] 闫德胜[1] 戎利建[1] 

机构地区：[1]中国科学院金属研究所,沈阳110016

出　　处：《金属学报》2014年第4期447-453,共7页Acta Metallurgica Sinica

基　　金：国家自然科学基金重大研究计划资助项目91226204~~

摘　　要：利用TEM和三维原子探针（3DAP）研究了一种Fe—Cr-Ni-Mo高强钢中碳化物随回火温度的变化及其对力学性能的影响．结果显示，回火温度较低（400℃）时，钢中析出M3C合金渗碳体及M7C3合金碳化物，M为Fe，Cr和Mn的组合，其中M3C长度约为1μm，而M7C3尺寸较小，小于200nm；回火温度较高时（500和600℃），碳化物析出数量增加，但M3C合金渗碳体尺寸变小，数量减少甚至不出现，同时析出尺寸较小的M2C和M6C（小于200nm）；继续提高回火温度（650℃），除M2C外还出现MC型碳化物，其尺寸小于100nm，析出数量减少．合金碳化物M2C，坛C和M6C的合金元素主要以V,Cr和Mo为主．高强钢的强度随回火温度的升高而下降，但在500～600℃回火温度区间，由于V碳化物析出会引起二次硬化效果，强度下降不明显，因此实验钢在530～600℃内回火后可获得较好的强韧性配合．The variation of carbides with tempering temperature in a Fe-Cr-Ni-Mo high-strength steel and their effect on mechanical properties are investigated by means of TEM and three-dimensional atom probe （3DAP）. The results show that there mainly appear M3C and M7C3 when tempering temperature is rather low （400 ℃）, the former is thick with a length of about 1 μm and the latter is fine and the length is less than 200 nm, and M is composed ofFe, Cr and Mn. Tempering at 500 and 600 ℃, the amount of carbide increases gradually, and there appear M2C and M6C types of carbide which are both less than 200 nm in length, simultaneously M3C becoming fine or disappear. When tempering temperature further increases to 650 ℃, besides M2C there also appears MC type of carbide. The size of both M2C and MC are less than 100 nm, meanwhile the amount of carbide decreases. The M of M2C, M6C and MC is a combination mainly of Cr, Mo and V. The strength of the Fe-Cr-Ni-Mo high-strength steel gradually reduces with increasing tempering temperature, but the downtrend of strength is rather small when tempering temperature is in the range of 500-600 ℃, owing to secondary hardening induced by the appearance of Vcarbide. In short, the high-strength steel could obtain better combination of strength and impact toughness after tempering at about 530-600 ℃.

关 键 词：Fe-Cr-Ni-Mo 高强钢 碳化物 回火温度 低温冲击韧性 

分 类 号：TG161[金属学及工艺—热处理]