灭茬刀火焰喷焊Fe6涂层组织及耐磨性能

Microsturcture and Wear-ability of the Stubble-cleaning Cutter with Flame Spray Welding Fe6 Coating

目的解决灭茬刀耐磨性不足,报废更换频繁的问题。方法在Q235钢基体上采用氧乙炔火焰喷焊技术制备Fe6涂层,分析涂层的硬度及微观组织形貌,并与原65Mn灭茬刀进行摩擦系数、磨损失重对比试验。结果 Fe6涂层与基体之间形成了良好的冶金结合。涂层组织主要由Fe-Cr-Ni固溶体合金相、Cr7C3相、Cr23C6相和Cr2B相组成,表面硬度平均值在56.6HRC左右,约为Q235钢的2倍。Fe6涂层摩擦系数稳定在0.65左右,约为65Mn灭茬刀试样的2/3;磨损失重实验进行3 h后,Fe6涂层与65Mn试样的磨损失重相差1倍左右。结论经氧乙炔火焰喷焊Fe6涂层进行表面强化后的Q235钢灭茬刀在硬度、耐磨性等方面得到显著提高,使用寿命可得到有效延长。该研究为氧乙炔火焰喷焊Fe6涂层在灭茬刀耐磨强化与修复上的推广及应用提供了可靠的依据,同时也为其他农业机械关键易磨损零部件的表面强化提供了一定的参考。

Objective To solve the problem of lack of wear resistance,frequent scrapping and replacement of the stubble-cleaning cutter. Methods Fe6 coating was prepared on Q235 steel substrate with flame spray welding technology. The hardness,microstructure and wear resistance were investigated by scanning electron microscope,energy depressive spectroscopy,X-ray diffractometer,microhardness tester and reciprocating friction testing machine,and the contrast test of the coefficient of friction and the wear loss was conducted between the original 65 Mn stubble-cleaning cutter and the coating. Results The metallurgical bond between coating and matrix was well formed. The microstructure of the coating was mainly composed of Fe-Cr-Ni phase,Cr7C3 phase,Cr23C6phase and Cr2B phase. The average surface hardness of the Fe6 coating was about 56. 6HRC and was almost 2 times that of the Q235 steel. The coefficient of friction of the Fe6 coating was about 0. 65 and was about 2 /3 of that of the 65 Mn stubble-cleaning cutter sample. After 3 hours of wear weight loss experiment,the difference of the wear weight loss between Fe6 coating and 65 Mn sample was about 1 fold. Conclusion After welding,the hardness and wear resistance of the stubble-cleaning cutter were significantly increased and the service life could be effectively extended. This study provides a reliable basis for the popularization and application of the flame spray welding Fe6 coating in wear-resistant strengthening and repairing of stubble-cleaning cutter,and at the same time also provides theoretical and practical basis for the surface strengthening of other easy-wear parts in the agricultural machinery.