Fe-Cr-C耐磨堆焊合金中初生碳化物生长方向的控制

用两种方法对Fe-Cr-C系耐磨堆焊合金中初生碳化物的生长方向进行了研究。探讨了含碳量(质量分数，％)分别为3．34、4．11、5．16和6．5的耐磨堆焊合金碳含量及铬一碳比对初生碳化物的生长方向的影响，并采用控制冷却条件的方法对堆焊层微观组织中碳化物定向生长进行了研究。得出了冷却条件对初生碳化物生长方向的影响规律。试验结果表明，碳含量及冷却条件对耐磨堆焊层的金相组织起决定性的作用，提高含碳量或降低铬一碳比会使Fe-Cr-C系耐磨堆焊合金中初生碳化物趋向垂直于耐磨堆焊层表面生长，并且初生碳化物的密度显著提高。冷却条件和散热方向可以有效地控制初生碳化物的生长方向，采用基板背面水冷却的方法可以使初生碳化物趋向垂直于耐磨堆焊层表面生长。当改变冷却条件降低冷却速度时，初生碳化物会随机地沿任何方向生长。

Orientation control of primary carbide in Fe-Cr-C hardfacing alloys

Microstructures of three kinds of high carbon Fe-Cr-C hardfacing alloys with carbon contents of 4.11%,5.16%,6.5% respectively were studied in this paper, and growth orientation of the carbide in the microstructures of the hardfacing layer was investigated by controlling cooling condition. The results show that the carbon contents and cooling conditions play an important role in the formation of the microstructures of the overlayer. Increasing carbon contents or decreasing Cr/C will make the orientation of primary carbide vertical to the surface of the overlayer, and the carbide will become more compact. The cooling condition can control the orientation of primary carbide effectively. By use of water-cooling method the primary carbide tends to the orientation vertical to the surface. When the cooling rate is lower, the primary carbide will grow randomly along any direction.