镍基泡沫防砂筛管TIG焊接头组织性能

Microstructure and property of TIG welding joint of nickel foam sand screen tube

以厚度为6 mm的镍基泡沫金属为研究对象,采用TIG焊并选用Inconel625与Inconel600两种焊丝,探讨焊接工艺对焊缝成形、接头组织和性能的影响。结果表明在本试验条件下,选用Inconel625焊丝,焊接电流为60 A,焊前预热150℃,Y形坡口和间断填丝的工艺时,所得到的焊接接头力学性能最优,抗拉强度可达21.37 MPa,约为母材的96.0%;接头断口以韧窝为主,且部分韧窝中存在以碳化物和非金属夹杂为主的第二相质点;焊缝表面为等轴晶,焊缝中部为等轴晶和树枝晶,层道交界处为胞状晶和柱状晶,熔合区为胞状晶和胞状树枝晶,热影响区晶粒明显长大;焊缝区和熔合区主要由γ-Ni和γ固溶体构成。

The foam nickel with the thickness of 6 mm was selected for study.The TIG welding was used with Inconel625 and Inconel600 welding wires.The effects of welding process on welding formation,joint microstructures and properties were investigated.The results indicate that,under the test condition,when the Inconel625 welding wire is selected,the welding current is 60 A,the preheating temperature is 150℃,the Y-shaped groove and intermittent wire filling process are adopted,and the mechanical properties of the welded joint are the best.That is to say,the tensile strength can amount to 21.37 MPa,which is about 96.0%of the base metal.There are dimples on the surface and some dimples contain second phase particles mainly composed of carbides and nonmetallic inclusions.The welding joint surface is covered with equiaxial crystals,the middle part of the welding joint is equiaxed crystal and dendrite,the cellular crystals and columnar crystals are distributed in the junction of layers,and the cellular crystals and cellular dendrites are distributed in the fusion zone.The grains in the heat affected zone grow obviously.The main phase of the welding zone and fusion zone are theγ-Ni andγsolid solution.