论文部分内容阅读
通过实验室EH40船板钢的超大热输入焊接热模拟实验,研究焊接熔合线部位的组织与性能,分析钢中夹杂物对原奥氏体晶界及晶内组织的影响规律.结果表明:实验钢在采用800 kJ/cm(t_(8/5)=730 s)的焊接热输入,峰值温度为1400℃(保温30 s)的条件下,-20℃的冲击功能够达到150 J以上.其金相组织由块状的晶界铁素体(GBF)、晶内多边形铁素体(IPF)、晶内针状铁素体(IAF)组成,且IAF面积分数占50%以上,无板条贝氏体和粒状贝氏体组织.实验钢中夹杂物类型合理、密度大,有效地抑制了GBF的粗化.钢中存在的直径为5—8μm的大尺寸夹杂物,也具有IGF形核能力,甚至会形成IAF组织,表现出贫Mn区的形核机制.
Through the large heat input welding thermal simulation experiment of EH40 shipbuilding steel in the laboratory, the microstructure and properties of weld fusion line were studied, and the influence of inclusions on the original austenite grain boundaries and microstructure was analyzed.The results show that the experiment Under the welding heat input of 800 kJ / cm (t_ (8/5) = 730 s) and the peak temperature of 1400 ℃ for 30 s, the impact energy of -20 ℃ can reach over 150 J. The microstructure consists of massive grain boundary ferrite (GBF), intragranular polygonal ferrite (IPF) and intragranular acicular ferrite (IAF) with an area fraction of IAF accounting for more than 50% Bainite and granular bainite. The type of inclusions in the experimental steel is reasonable and its density is large, effectively inhibiting the coarsening of GBF. Large inclusions with a diameter of 5-8 μm exist in the steel and also have IGF nuclei Ability, and even the formation of IAF organizations, showing the nucleation mechanism of poor Mn area.