激光重熔Fe基合金火焰喷焊层的组织和性能研究

Microstructure and Performance of Laser Remelted Flame Spray-welding Layer of Fe-based Alloy

采用金相显微镜、扫描电镜、X射线衍射物相分析和显微硬度、耐磨性测定等试验手段,研究了激光工艺参数以及回火温度对重熔的Fe基合金火焰喷焊层组织和性能的影响。试验结果表明,经激光重熔后,火烟喷焊层的组织明显细化。重熔喷焊层回火态的组织主要由α-Fe及Cr23C6、Cr7C3、CrB、Fe3B、Fe2B、FeB等强化相组成,重熔喷焊层的硬度明显高于原火焰喷焊层。在激光功率相同的条件下,经高速扫描的重熔喷焊层硬度高于经低速扫描的,然而两者经不同温度回火,都是在650℃×3h回火后的硬度达到最高值。在耐磨性方面,重熔喷焊层好于原火焰喷焊层,经高速扫描的重熔喷焊层好于经低速扫描的,回火态的优于未经回火的。

The effect of laser process parameters and tempering temperatures on the microstructure and performance of remehed spray-welding iron-based alloy layer was studied by optical microscope, SEM, XRD, microhardness and wearability tests. Test results show that the microstructure in laser remelted flame spray-welding layer was obviously fined. The as-tempered microstructure consists of ot-Fe and such strengthening phase as Cr23C6,CrTC3,CrB, Fe3B,FeEB and FeB. The hardness of remehed layer is considerably higher than that of unremelted layer. The hardness of spray-welding layer remehed at high laser scanning speed is h!gher than spray-weldlng layer remelted at low laser scanning speed when laser power is identical. When the two remehed layers are temperd at different temperature, however, their highest hardness offers after being tempered at 650 ℃ for 3 h. As for wearability, the remehed spray-welding layer is superior to unremelted spray-weldlng layer, spray-welding layer remelted at high laser scanning speed is superior to spray-weldlng layer remehed at low laser scanning speed, and as-tempered （650 ℃ × 3 h） remehed spray-welding layer is superior to untempered remelted spray-welding layer.