W对Fe-Cr-Mo-W-V热锻模具堆焊合金组织与性能的影响

Effect of tungsten on microstructures and properties of Fe-Cr-Mo-W-V hot working dies deposited metal

针对热锻模具工作条件及其失效形式,采用药芯焊丝气体保护堆焊方法制备Fe-Cr-Mo-W-V系热锻模具堆焊合金,采用金相组织观察、硬度测试、回火热处理、抗热疲劳裂纹和力学性能等多种试验方法,分析了W含量对堆焊合金显微组织、焊态硬度、热稳定性、热疲劳性能以及力学性能的影响。结果表明:Fe-Cr-Mo-W-V系堆焊合金的显微组织由板条马氏体+残余奥氏体组成。随着W含量的增加,堆焊合金焊态及550℃回火处理后所对应的硬度值逐渐增加,随着热处理时间的延长,堆焊层硬度逐步降低并趋于平缓。随着堆焊合金中W元素的增加,堆焊合金抗热疲劳裂纹性能逐渐降低,Fe-Cr-Mo-W-V系堆焊合金的抗拉强度略高于国外焊接材料Weld Mold 9650,断后伸长率略低于焊接材料Weld Mold 9650。

To deal with the service condition and failure mode of hot working die,Fe-Cr-Mo-W-V based dies hard alloys were deposited by flux-cored wire using metal inert-gas welding( MIG). Using a variety of test methods,such as microstructures observation,hardness test,tempering heat treatment,thermal fatigue resistance test,the effects of tungsten contents on the microstructures,weld hardness,thermal stability,thermal fatigue resistance and mechanical properties of the hardfacing alloys were analyzed. All as-welded Fe-Cr-Mo-W-V deposits showed a microstructure composed of lath martensite and retained austenite. The hardness of as-welded and after 550 ℃ heat treatment hardfacing alloys increasesd with the increasing of tungsten content. With the increasing of heat treatment time,the hardness of hardfacing alloys gradually decreased and became flat,the thermal stability of the developed hardfacing alloys are similar to foreign welding material( 9650).With the increasing of tungsten content in hardfacing alloys,thermal fatigue cracking performance of the developed surfacing alloy gradually reduced. Tensile strength of Fe-Cr-Mo-W-V based hardfacing alloy was slightly higher than 9650,while the elongation of the alloy was lower than 9650.