Optimization of compositions of Fe Ni Cr BC laser cladding layer for mine support based on Thermo-Calc

Aiming at the problem of poor corrosion resistance and easy cracking of the Fe Ni Cr BC cladding layer for mine supports,the content of Ni and Nb elements in the cladding layer was adjusted to increase the content of retained austenite in the cladding layer and reduce the phenomenon of intergranular chromium depletion,so as to arrive the purpose of decreasing crack sensitivity and improving corrosion resistance. In this study,the influence of contents of Ni and Nb elements on the microstructure and precipitated phase in Fe Ni Cr BC cladding layer was investigated through the thermodynamics software Thermo-Calc. The chemical compositions of cladding layer were optimized based on the research results. The result showed that the percentage of σ phase decreased with the Ni content increasing from 1% to 8%. The proportion of retained austenite in Fe Ni Cr BC cladding layer reached the maximum when the Ni content was 4%. With the addition amount of Ni element increasing from 0.3% to 2.0%,the Cr content in martensite first increased and then tended to be steady,and it in carbide and boride decreased gradually,while the amount of Nb in such two compounds increased. After the elements Ni and Nb were adjusted to 4% and 1% respectively,the corrosion resistance of Fe Ni Cr BC cladding layer got improved apparently,and also the cracking susceptibility decreased obviously.