论文部分内容阅读
用光学、电子金相、X射线衍射和膨胀等方法研究了4Cr3Mo2V热作模具钢淬火组织在回火过程中的变化及对常规力学性强的影响。结果表明,随营回火温良的升高,发生马氏体脱溶和M_3C→V_4C_3+Mo_2C+(Cr,Fe)_7C_3→V_4C_3+M_6C 转变,并于750℃发生马氏体板条再结晶,结果强度在590～810℃回火对,冲击韧性在600～820℃回火时,出现峰值,二者随着回火温度升高几乎同向变化。该钢的回火抗力很高,这与其钒高、铬低、钼高有关。增钒强化 V_4C_3的弥敌强化作用;降铬、增钼则使 Cr 与(Cr+Mo+O.7W)原子比降至0.69,从而抑制了稳定性较差的(Cr,Fe)_7C_3析出。
The changes of quenched microstructure of 4Cr3Mo2V hot work tool steel during tempering and the effect on conventional mechanical properties were studied by means of optical, electronic metallography, X-ray diffraction and expansion. The results show that martensite desolvation and the transformation of M_3C → V_4C_3 + Mo_2C + (Cr, Fe) _7C_3 → V_4C_3 + M_6C with recrystallization of martensite at 750 ℃ occurred with the increase of tempering temperature. Temperatures range from 590 ° C to 810 ° C, and impact toughness peaks from 600 ° C to 820 ° C, both of which change almost in the same direction as the tempering temperature increases. The steel has high tempering resistance, which is related to its high vanadium, low chromium and high molybdenum. (Cr, Fe) _7C_3 with Cr and Mo decreased the atomic ratio of Cr to (Cr + Mo + O.7W) to 0.69, which restrained the less stable precipitation of (Cr, Fe) _7C_3.