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我们在对45钢模锻件锻热淬火的研究过程中,发现在相同的腐蚀条件下,经形变淬火的奥氏体晶界不易腐蚀。观察经形变淬火和高温淬火的淬透性试样,发现经形变淬火的奥氏体晶界上屈氏体的析出较经高温淬火的晚;经机械性能试验发现前者的韧性要明显的高于后者。我们认为这可能是由于两者晶界上的化学成份不同所致。鉴于上述,我们又用电子探针等作了化学成份分析,结果表明,在高温淬火的奥氏体晶界上存在S、Si杂质元素的富集;而形变淬火的奥氏体晶内及晶界上S、Si杂质元素则呈均匀分布,即晶界存在净化现象。因此可以认为晶界的净化是高温形变热处理(包括锻热淬火)能获得强韧化的重要原因之
In our research on forging quenching of 45 steel forgings, we found that under the same corrosion conditions, the austenite grain boundaries quenched by deformation are not easily corroded. It was observed that the precipitation of quenching of austenite grain boundaries by deformation and quenching was delayed by high temperature quenching after the deformation hardened and high temperature quenched hardenability specimens were observed. The mechanical property test showed that the toughness of the former is obviously higher than the latter. We think this may be due to the difference in chemical composition between the two grain boundaries. In view of the above, we also made chemical composition analysis using electron probe, the results show that there is enrichment of S, Si impurity elements in the austenite grain boundaries quenched at high temperature, while the deformation quenching of austenite and crystal Boundary on the S, Si impurity elements were evenly distributed, that is, there is purification of the grain boundary phenomenon. Therefore, it can be considered that the grain boundary decontamination is an important reason that the high temperature deformation heat treatment (including forging quenching) can obtain the toughness