20钢管高温钎焊与瞬时液相扩散焊接组织与性能

采用镍基钎料BN边和自主研制的铁镍基中间层合金进行了20钢管的焊接试验，以扫描电镜、能量散射X射线和电子探针分析了它们的焊缝组织形貌、成分分布以及焊接性能之间的差异。结果表明，采用镍基钎料BNi2高温钎焊20钢管，接头组织为典型的Ni固溶体钎缝特征，与母材组织存在明显的钎缝界限，接头区成分分布不均匀且有Si脆性相存在，接头无韧性；采用铁镍基中间层瞬时液相扩散焊接20钢管，可获得与母材相似并连续的接头组织，接头成分分布均匀且无Si脆性相生成，接头强度、韧性均达到母材水平，其性能远远高于高温钎焊。

Microstructure and properties of 20 steel pipe joints by transient liquid phase bonding and high temperature brazing

20 steel pipes were joined with a convention nickel base brazing filler metal BNi2 and a novel iron-nickel base foil,and the mechanical properties and microstructure of them were investigated using scanning electron microscope,energy dispersive X-ray analysis and electron probe microanalysis.The results showed that BNi2 brazing produced Ni solid solution joints with silicide precipitates and heterogeneity composition.In contrast,however,transient liquid phase bonding using iron-nickel base foil,resulted in homogenous joints with microstructure and composition similar to the parent metal and free of silicide precipitates.Mechanical tests showed that bonding properties of joints made using iron-nickel base foil were superior to those obtained using BNi2.When the iron-nickel base foil was used,bonding toughness was near parent toughness.