煤化工用调节阀耐磨涂层工艺技术研究

Technology research on wear-resistant coating of control valve in coal-chemical industry

针对煤化工用调节阀的特殊工况,为了提高阀内件表面的耐磨性,采用超音速火焰喷涂(high velocity oxy-fuel,HVOF)、等离子喷涂(atmospheric plasma spray,APS)及熔敷、等离子堆焊(plasma transferred arc,PTA)3种典型的处理工艺,并结合上述工艺选取与之相匹配典型的喷涂材料。通过磨损试验、硬度测试和显微组织结构的研究发现:APS喷涂的温度较高,引起碳化物分解并溶解于基体内,经过熔敷,涂层韧性增加,磨损表面不易产生裂纹和剥落;HVOF喷涂过程中,粒子的撞击速度高,不会产生过热现象,涂层受压应力、密度高,耐磨性好;PTA堆焊的涂层和基体的结合力较强,硬度高,涂层厚度大,耐磨性介于APS和HVOF之间。

Aiming at the special conditions of the valves used in coal chemical industry, in order to improve the wear resistance of the valve trim, three typical processing technologies are adopted, which are high velocity oxy-fuel （HVOF）, atmospheric plasma spray（APS） and plasma transferred arc （PTA） ; and the typical materials that match the above processing technologies are selected to spray the sample. Abrasion test, hardness test and micro-structure analysis reveal that APS uses much higher spraying temperature than HVOF, which could contribute to the carbide oxidation and dissolution in the matrix, after deposition the coating flexibility increases and the worn surface is diffi- cult to be cracked down and peeled off. In HVOF spraying process, the particles have high impact speed and over- heating does not happen; and the coatings are under compressive stress, have high density and good wear resistance characteristic. The coating of PTA hardfacing has strong binding force with the base material, high hardness and good thickness,its wear resistance characteristic is between those of APS and HVOF.