20钢瞬时液相扩散焊降熔元素的扩散过程研究

Study on MPD Elements Diffusion Process of 20 Steel Transient Liquid-phase Diffusion Bonding

用FeNiCrSiB非晶箔作中间层,氩气保护,在一定的焊接工艺条件下,通过采用不同保温时间的方法,分析了随等温时间的增加,20钢瞬时液相扩散焊接头金相组织的变化以及降熔元素B、Si的扩散过程。焊缝接头始终有两个比较明显的界面,并且随等温时间的延长两个界面变化不明显。等温时间10s降熔元素扩散已比较明显,而在10s到60s的等温凝固阶段,B、Si的扩散都不明显,到180s时,B、Si的扩散都达到了比较理想的效果,得到了力学性能较好的焊接接头。

Using FeNiCrSiB amorphous as interlayer in argon atmosphere, the melting point depressant （MPD） elements diffusion process and the microstructure change of 20 steel transient liquid-phase bonding were analyzed by changing holding time while other process parameters was invariable. The result show that the bonding .line has two explicit interfaces, and the interfaces change little with the increase of holding time. The MPD elements diffusion is obvious at holding time of 10s, but as the holding time is 10-60s, the diffusion is unobvious. When the holding time increases to 180s, the MPD elements has a absolute diffusion,and achieves a perfect bonding joint.