两种中碳铬镍钼钢高温回火态的延性断裂韧度

INVESTIGATION OF DUCTILE FRACTURE TOUGHNESS FOR TOW TEMPERED Cr-Ni-Mo STEELS

通过对阻力曲线（Ｊ＿Ｒ－△ａ）的剖析，结合ＴＥＭ组织和ＳＥＭ断口分析，研究了两种中碳铬镍钼钢高温回火态的延性断裂韧度。结果表明：在５００～５９０℃回火时条件断裂韧度Ｊ＿（０．２）随回火温度升高而增大，而启裂断裂韧度Ｊ＿ｉ随回火温度变化的规律较为复杂。这是因为决定材料抵抗裂纹启裂能力大小的主要因素是Ｊ＿ｃ（弹性分量），而ｄＪ＿ｐ／ｄａ则能明显影响裂纹稳定扩展能力的大小。

Through the resistance curves(J_R-△a) measurement and in conbination with the TEM microstructure and SEM surface fracture analysis,the ductile fracture toughness of two high tempered medium carbon Cr-Ni-Mo steels was investigated.Results show that in 500～590℃ range,with the increase of tempering temperature,the J_(0.2)increases monotonously,however the change law of J_i appears more complicate.The elastic component(Je)is the control factor which can influence the ability of initial cracking,the stable propagating capacity of a crack is obviously affected by the value of dJ_p/da.