矿用钛合金钻杆表面复合强化与摩擦性能研究

Surface Combined Strengthening and Wear Properties of Titanium Alloy Drill Pipe for Mining

为提高矿用钛合金钻杆的耐磨性能,以低成本粉末冶金Ti-Al-Fe-Mo合金为研究对象,采用表面机械碾磨与固相渗碳相结合的创新方式对其表面进行复合强化处理,研究不同表面碾磨道次加渗碳处理的钛合金表面的微观组织及其显微硬度。以氮化硅球为摩擦对偶,对表面复合强化钛合金样品进行往复式滑动摩擦试验,研究钛合金表面强化层对其磨损量、摩擦因数、表面磨痕微观组织的影响规律。结果表明:表面机械碾磨方法可以在粉末钛合金表面形成梯度纳米晶结构;钛合金经过表面机械碾磨处理后可显著提高表面渗碳的深度和均匀度;经表面机械碾磨与固相渗碳复合强化处理的钛合金,其磨损量相比于单一表面渗碳的钛合金降低了近58%。表面复合强化的钛合金摩擦磨损机制以疲劳磨损、黏着磨损、氧化磨损和少量的磨粒磨损为主。

In order to improve the wear resistance of titanium alloy drill pipe, the combined strengthening method of surface mechanical grinding treatment and carburizing was used on the surface of low-cost powder metallurgical Ti-Al-Fe-Mo alloy.The microstructure evolution and microhardness distribution of the surface treated with different surface grinding passes and carburization were investigated.The reciprocation sliding wear tests were carried out on the titanium alloy samples treated by different grinding passes and carburization using silicon nitride ball as friction pair.The effects of surface strengthening layer of titanium alloy on its wear loss, friction coefficient and the microstructure of worn track were studied.The results show that the gradient nanocrystalline structure is formed on the surface of powder metallurgical titanium alloy by surface mechanical grinding treatment, and the carburizing depth and uniformity of titanium alloy is significantly improved after surface mechanical grinding treatment.Compared with the surface carburized titanium alloy, the wear loss of the titanium alloy treated by the combined strengthening of surface mechanical grinding treatment and carburizing is reduced by 58%.Fatigue wear, adhesion wear, oxidation wear and some abrasive wear are the main wear mechanisms of surface combined strengthening titanium alloy.