材料期刊网

用Auger电子能谱(AES)研究了含磷450ppm的35CrMnSi和35CrNi3钢回火脆性与杂质元素磷及合金元素Ni,Cr,Mn晶界偏聚的关系。含磷钢的回火脆性主要是由磷在原奥氏体晶界偏聚所致。经1200℃油淬、625℃回火1h水冷的所谓“韧态”,磷已在晶界大量偏聚,钢已明显脆化;经阶梯冷却脆化处理后,晶界磷浓度成倍增加。在阶梯冷却脆化期间,Ni-Cr钢中磷的晶界偏聚速率比Cr-Mn-Si钢大。试验钢的FATT与晶界含磷量成正比;Ni-Cr钢中晶界Ni与磷呈线性关系。试验钢中加入La能够减少相同状态下的晶界磷浓度,从而改善钢的回火脆性。

An Auger electron spectroscopical study was made of the correlation between the temper brittleness and the grain boundary segregation of P together with alloying elements as Ni, Cr and Mn in steels 35CrMnSi and 35CrNi3 containing 450 ppm P. It was shown that the steels tested attributed substantially their temper brittleness to the P segregation along the prior austenite grain boundaries. Although in so called "ductile state", namely oil quenched at 1200℃, tempered at 625℃ for 1h and water quenched, a lot of P segregated already along the grain boundary, thus, the steels embrittled markedly. After embrittlement treatment by step cooling, intergranular P concentration increased sharply. During this treatment, the increasing rate of P segregation along grain boundary in Ni-Cr steel is greater than that in Cr-Mn-Si steel. The FATT of the steels tested is directly proportional to the intergranular P content. The intergranular segregation of Ni in Ni-Cr steel is related linearly to that of P. To the steels, the addition of La may improve their temper embrittlement owing to decrease of intergranular P concentration under similar state.