摘要:
为提高H13钢表面的硬度和耐热稳定性,采用激光熔覆技术在H13钢表面制备了9%Ni的Fe基涂层。利用X射线衍射仪(XRD)、金相显微镜、扫描电子显微镜(SEM)、能谱仪(EDS)、显微硬度仪等研究了合金涂层微观组织结构、物相组成、显微硬度及热稳定性。结果表明,熔覆层与基体结合良好,从熔覆层到基体凝固组织呈等轴晶、树枝晶、柱状晶、胞晶等组织形态分布;涂层物相主要是α-Fe、γ-(Fe,Ni)和金属间化合物Ni3Fe增强相,此外,还应弥散分布Fe-Ti、Fe-Cr、Ti-Al等化合物,因为含量少,XRD检测不到;熔覆后的涂层显微硬度达到基体组织的1.5~2倍,硬度的提升显著强化了基体;涂层热稳定性能良好,400℃下时效时最稳定。采用该Fe基合金涂层可以显著提高H13钢钢材硬度和热稳定性,延长其使用寿命。
Abstract:
In order to improve the hardness and heat resistance stability of H13 steel surface,a 9% Ni-Fe alloy coating was prepared on the surface of H13 steel by laser cladding technology.Microstructure,phase composition,and micro-hardness of the alloy coating and thermal stability was investigated by X-ray diffraction（XRD）,metallographic microscope,scanning electron microscope（SEM）,energy spectrometer（EDS）,micro-hardness tester and other experimental instruments.The results show that the cladding layer is well bonded to the substrate without presence of defects such as cracks and pores. From the cladding layer to the matrix,the solidified structures arechanging from equiaxed,dendritic,columnar to cellular.The coating phase is mainly composed of α-Fe and some intermetallic compound reinforcing phases,and its content is beyond XRD detection. The micro-hardness of the coating after cladding has reached 1.5 to 2 times of the matrix structure,and the increase in hardness has significantly strengthened the matrix. The coating has good thermal stability and is the most stable at 400 ℃ .The Fe-based alloy coating can significantly improve the hardness and thermal stability of H13 steel and extend its service life.
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