摘要
硅作为低碳贝氏体钢中的一种主要合金元素,在一定含量范围内可有效地提高钢中残留奥氏体量及其热稳定性和机械稳定性,从而使钢的强韧性得到改善。本文试验表明,随着硅含量增加,低碳贝氏体钢的强度和韧性呈先增加后降低的规律变化,在某一硅含量下强度和韧性同时达到最大。在冷却速度Vt=156℃/min时强度和韧性都达到最大的硅含量为1.62%;在Vt=7.5℃/min和0.9℃/min时硅含量为1.99%。由于硅含量和冷却速度不同,在低碳贝氏体钢中存在四类不同形态的M-A岛:第一类为全马氏体岛;第二类为全残留奥氏体岛;第三类为中心是马氏体外围是残留奥氏体的岛;第四类是外围是马氏体中心是残留奥氏体的岛。其中第二、三类M-A岛有利于提高钢的韧性。
The strength and toughness of the low carbon bainitic steels could be improved because the amount of retained austenite and its chemical stability and mechanical stability are increased by silicon as one of main alloy elements in the steels. The experimental results show that the strength and toughness of the steels are increased at first then decreased with the increasing of silicon content and they are reached maximum simultaneously at some silicon content,i, e. It is 1.62% Si at the cooling rate V_t=156℃C/min and 1.99%Si at V_t=7. 5℃/min or 0.9℃/min. As the silicon content and the cooling rates are changed the M-A island in Low carbon bainitic steels will have four type morphologies. The first M-A island is entire martensite, the second one is entire retained austenite,the retained austenite is around martensite in the thired one and the martensite is around the retained austenite in the forth. The second and the third M-A islands are beneficial to improving toughness of the steels.
出处
《金属热处理》
CAS
CSCD
北大核心
1992年第9期7-12,21,共7页
Heat Treatment of Metals
