原位自生TiC对高铬铸铁堆焊金属组织与性能的影响

Effect of In-Situ Synthesis TiC on Microstructure and Properties of High Chromium Cast Iron Surfacing Metal

以自制的高铬铸铁药芯焊带为焊接材料,采用非熔化极惰性气体保护电弧焊(TIG)在低碳钢板上进行单层单道堆焊试验,通过在药芯焊带药粉中添加不同质量分数(0~5.2%)的钛铁粉,研究了原位自生TiC对堆焊金属组织和性能的影响。结果表明:药芯焊带药粉中加入钛铁粉后,堆焊金属中除了含有Cr_(7)C_(3)硬质相外,还原位析出TiC相,Cr_(7)C_(3)尺寸减小,分布更均匀,数量明显增加;当药粉中钛铁粉质量分数为5.2%时,堆焊金属中Cr_(7)C_(3)细化最明显,分布最均匀;随着药芯焊带药粉中钛铁粉含量的增加,堆焊金属的硬度和耐磨性提高。液态金属中原位合成的TiC可作为Cr_(7)C_(3)的异质形核核心,减小了Cr_(7)C_(3)的形核阻力,从而细化了Cr_(7)C_(3)。

Using self-made high chromium cast iron flux-cored welding tape as welding material,single-layer single-pass surfacing tests were carried out by non-melting inert gas arc welding(TIG)on low carbon steel plate.The effect of in-situ synthesis TiC on the microstructure and properties of surfacing metal was studied by adding different mass fraction(0-5.2%)of ferro-titanitum powder in the flux-cored welding tape powder.The results show that after adding ferro-titanium powder to the flux-cored welding tape powder,there was in-situ synthesis TiC phase in the surfacing metal except Cr_(7)C_(3) hard phase;the size of Cr_(7)C_(3) decreased,the distribution was relatively uniform,and the number increased significantly.When the mass fraction of ferro-titanium powder in the powder was 5.2%,the refinement of Cr_(7)C_(3) in the surfacing metal was the most obvious,and the distribution was the most uniform.With increasing ferro-titanium powder content in the flux-cored welding tape powder,the hardness and wear resistance of the surfacing metal increased.The TiC synthesized in situ in the liquid metal could be used as the heterogeneous nucleation core of Cr_(7)C_(3),which reduced the nucleation resistance of Cr_(7)C_(3) and thus refined Cr_(7)C_(3).