不锈钢背锡青铜梯度自润滑材料的评价

Evaluation of stainless steel back tin-bronze gradient self-lubricating composites

  • 摘要: 为了研制一种高性能自润滑轴承内套圈材料,以锡青铜、316L不锈钢和MoS2粉末为原料,采用多坯料挤压成形与烧结致密化相结合的方法,制备了芯部承压层为316L不锈钢,表面固体润滑层为锡青铜和MoS2,中间过渡层为锡青铜、  316L不锈钢和MoS2的不锈钢背锡青铜梯度自润滑复合棒材,采用光学金相显微镜(OM)和扫描电镜(SEM)对其微观组织进行观察、并采用万能材料试验机(MTS)和摩擦磨损试验机对其物理力学性能和摩擦性能进行测试。结果表明:在氢气保护气氛下,1050℃保温2 h可以制备出致密性良好,各层显微组织过渡平缓,硬度和摩擦因数沿径向呈梯度分布的自润滑材料。材料实测平均密度8.35 g·cm-3,相对密度96.8%;径向压溃强度950 MPa;自润滑层工作面摩擦因数约0.30,显微维氏硬度1。44 GPa;磨损率5.2×10-9 m·N-1·m-1。与其他固体自润滑材料相比,不锈钢背锡青铜梯度自润滑材料的力学性能、耐磨性能等显著提高。

     

    Abstract: In order to develop a high performance self-lubricating material for bearing inner rings,a kind of stainless steel back tin-bronze gradient self-lubricating composites made of tin-bronze,316L stainless steel and MoS2 powders was prepared by the multi-billet extrusion method and sintering densification process. This material is composed of supporting layer made of 316L stainless steel powders,solid-lubricating layer mixed with tin-bronze and MoS2 powders,and transitional layer mixed with the powders of two front layers. The microstructure was characterized by OM and SEM. The wear and physics mechanical properties were investigated by the MTS and friction-wear tester. The results show that the structure of composites is compact,the interface of each layer transits gently under the process of 1050℃ and the holding time 2 h. The hardness and coefficient of friction gradually increase from the solid-lubricating layer to the supporting layer. The measured average density of sintered composites is 8.35 g·cm-3,and the relative density is 96.8%. The radial crushing strength is 950 MPa. The friction coefficient of working surface of the self-lubricating layer is about 0.30. The micro Vickers hardness of it is 1.44 GPa,and the wear rate is 5.2×10-9 m·N-1·m-1. Compared with  other solid-lubricating materials,the mechanical properties and wear resistance capability of stainless steel back tin-bronze gradient self-lubricating composites are greatly improved.

     

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