热处理工艺参数对结构钢内部裂纹愈合的影响

Effect of Heat Treatment Technical Parameter on the Inner Crack Healing in Structural Steel

用钻孔压缩法在试样内部引入裂纹，然后对含内部裂纹的试样进行不同加热温度和不同保温时间的空冷处理，采用金相显微镜及扫描电镜观察分析裂纹愈合程度，研究了热处理工艺参数对20钢、45钢、20CrMnTi钢内部裂纹愈合的影响。结果表明：温度是影响裂纹愈合的主要因素，而加热时间的影响次之；裂纹愈合存在临界温度，此-临界温度应大于该材料的最低再结晶温度。

Inner crack is prepared in the materials by compressing drilled hole, and then the samples are heated at different temperature for different time and cooled in air. Microscope and SEM was employed to examine the effect of crack healing. The effect of heat treatment technical parameter on the inner crack healing in 20 steel ,45steel and 20CrMnTi steel is studied. The results indicate that the effect of crack healing depends mainly on the heating temperature rather than the heat retaining time. A critical temperature exists in the crack healing. The critical temperature should be higher than the recrystallization temperature of the material.