合金元素对一种多元合金钢可逆回火脆性的影响

Effect of Alloying Elements on Temper Embrittlement of Multicomponent Alloy Steel

研究了合金元素对一种多元合金钢可逆回火脆性的影响。结果表明，产生可逆回 火脆性的温度范围是４００～５５０℃．主要原因是Ｐ在晶界上的偏聚．沿晶单位面 积的断裂功与Ｐ的偏聚量有Ａｋ＝０．４４－３．４Ｊ／ｍｍ２关系。式中，为Ｐ在 积的断裂功与Ｐ的偏聚量有Ａｋ＝０．４４－３．４ＹＪ／ｍｍ２关系。式中为Ｐ在 晶界偏聚位置分数。阶梯回火不但加速了Ｐ的偏聚速度，而且提高了平衡偏聚量。 合金中的Ｃ排斥Ｐ，并且Ｃ本身有增强晶界结合力的作用，因此适量的Ｃ对防止 可逆回火脆性是有好处的；Ｃｒ有明显促进Ｐ在晶界偏聚的作用．其原因足Ｃｒ与 Ｃ之间交互作用较强；Ｍｎ，Ｎｉ，Ｃｕ山于都会促进Ｐ在晶界的偏聚，所以不同程 度的促进了可逆回火脆性。

Effect of alloying elements of a multicomponent alloy steel on the temper embrittlement is investigated. Temper embrittlement appears in temperature range of 400~550°C. Temper embrittlement arises from P segregation at grain boundaries. Absorbed-in-fracture energy per unit area on grain boundaries can be described dy experimental relation Ak=0.44-3.4Y (J/mm2) where is the segregation site fraction of P. Step-temper increases the P segregation both in rate and amount. Carbon excludes P and carbon increases the boundary conjunction, so sui-table amount of carbon is effective in preventing temper embrittlement. Cr increases the grain boundary segregation of P, because the interaction of Cr and C is very strong. Mn, Ni, Cu also increase the temper embrittlement in various degrees.