M42高速钢/X32弹簧钢电子束焊接温度场的数值模拟与实验研究

Experiment and numerical simulation of temperature field during electron beam welding of M42/X32

选择双椭球热源模型对M42高速钢/X32弹簧钢双金属带锯的电子束焊接的温度场进行Ansys数值模拟,确定焊接的最佳工艺参数,并进行焊接试验,利用扫描电镜观察M42/X32接头的微观组织。结果表明,最佳焊接工艺为焊接电压U=140 k V,焊接电子束电流Ib=20 m A,焊接速度v=2 m/min。在此工艺条件下进行电子束焊接实验,焊缝宽度实验值和计算值的相对误差为-3%~1.5%,二者吻合较好,验证了双椭球热源模型在电子束焊接温度场模拟中的适用性。M42/X32接头的焊缝中心为等轴晶和柱状晶的典型铸态组织;M42熔合区（FZ）组织为马氏体和M2C型碳化物,M42热影响区（HAZ）组织为马氏体、残余奥氏体及碳化物。X32熔合区（FZ）由类马氏体层和马氏体组织组成,X32热影响区（HAZ）组织为马氏体、残余奥氏体以及M23C6。

Finite element numerical model was established using FEA software-ansys to research the temperature field of M42/X32 bimetal blade saw. The best process that welding voltage should be 140 kV, welding current should be 20 mA and welding speed should be 2 m·min-1 can be concluded. Under such process, the calculation accuracy of the weld width between experimental results and simulations ranges from -3% to 1.5%. The simulations agree well with experimental results, which proves the validity and applicability of double ellipsoid heat source model on the temperature field of electron beam welding. A typical as-cast structure in weld seam can be obtained. Fusion zone of M42 consists of martensite and M2C zone and the microstructure of heat affected zone obtains martensite, retained austenite and carbonizations. While the fusion zone of X32 can be subdivided into martensite and martensite-like zone, and heat affected zone of X32 is made up ofmartensite, ferrite and M23C6 zone.