预热与焊后回火对铸钢基体双金属梯度堆焊锻模堆焊层组织与性能的影响

发布时间：2018-02-15 21:32

  本文关键词： 铸钢 预热温度 数值模拟 组织 性能　出处：《中南大学学报(自然科学版)》2017年09期 　论文类型：期刊论文

【摘要】：为解决大型锻模的高成本、低寿命等问题,提出铸钢基体表面堆焊制备大型液压机用锻模新方法,针对其中的焊前预热与焊后回火工艺,将有限元分析与试验分析相结合,研究预热温度与焊后回火对堆焊层组织与力学性能的影响机理。研究结果表明:常温堆焊时,堆焊熔合区组织为马氏体+碳化物+残留奥氏体;随着预热温度的升高,冷却时间不断延长,组织呈现马氏体→贝氏体→珠光体转变趋势,显微硬度逐渐降低;当预热温度为400℃时,熔合区组织为铁素体+珠光体;焊后550℃/2 h回火后,堆焊层及热影响区硬度下降,基体中析出大量碳化物,堆焊层冲击韧性显著提高,断裂方式以韧窝断裂为主,母材性能在回火后无明显变化,说明预热与焊后热处理使堆焊层获得了较好的综合力学性能。
[Abstract]:In order to solve the problems of high cost and low life of large forging die, a new method of preparing forging die for large hydraulic press by surfacing welding on cast steel substrate is put forward. The finite element analysis and test analysis are combined to solve the preheating and tempering process before welding and after welding. The effect of preheating temperature and tempering after welding on the microstructure and mechanical properties of the surfacing layer was studied. The results showed that the microstructure of the fusion zone of the surfacing welding was martensite carbides retained austenite at room temperature, and with the increase of preheating temperature, The cooling time is prolonged and the microstructure appears martensite. 鈫払ainite. 鈫扵he microstructure of the fusion zone is ferrite pearlite when the preheating temperature is 400 鈩，

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