保温时间对304不锈钢板翅结构真空钎焊的影响

Effect of holding time on vacuum brazing for 304 stanless steel plate-fin structure

应用镍基钎料BNi2对304不锈钢板翅结构进行真空钎焊试验,进行了强度试验和微观组织观察。研究了钎焊保温时间对强度和微观组织的影响。结果表明,保温时间对硼元素扩散影响很大,从而对强度和微观组织产生影响。保温时间太短,硼元素来不及扩散,遗留在钎缝中间生成脆性化合物,使得接头强度降低;保温时间太长,会导致母材过度溶解于钎缝,导致缺陷增加,同时太长时间的高温暴露,使得界面出现溶蚀现象。因此,对于304不锈钢板翅结构的钎焊,保温时间控制在25分钟左右较为合适。

The vacuum brazing experiments of 304 stainless steel plate fin structure was carried out. And the tensile tests of plate fin structure and scanning electron microscope （SEM）tests were carried out. The effects of holding time on tensile strength and microstructure were investigated.The results show that the holding time has great effect on tensile strength and microstructure.If the holding time is too short,the Boron can not diffuse to the base metal sufficiently, which leads that the residual Boron generate more brittle phases in the joint and decrease the strength.If the holding time is too long,the base metal will dissolve to the filler metal excessively,which generates more defects and decrease the strength. For the brazing of 304 stainless steel plate fin structure,the holding time should be kept around 25 minutes.