液压凿岩机活塞新材料开发和设计质量评估

Improving material properties and evaluating design quality of hydraulic rock drill's piston

研制了一种具有Cr Ni Mo新配比的低碳合金钢作为液压凿岩机冲击活塞用材 ,与常规活塞用材进行了金相组织、静强度、热处理后的表面和断面显微硬度及工业性对比试验 ,测试了凿岩机冲击性能。结果表明 :该材料具有良好的淬透性、合理的金相组织和断面硬度分布以及较好的力学性能。

A kind of low carbon containing alloy steel with composition (mass fraction, %) of 25CrNi3MoA was developed for making hydraulic drill piston which experiences long period cyclic impact stress. The experimental piston was made according to the designed sizes. Then heat treated, sampled and studied using microscopy and the results were compared with those of another piston made with conventional low alloy steels. Metallographic studying and industrial tests show that the experimental piston has very good microstructures and properties, and its working life exceeds 400 h with a total drilled hole length of 25 500m in a coal mine, which is about 3 times of that of the comparing piston made by conventional low alloy steel. In addition a method of using stress wave coefficient, φ K, to evaluate preliminarily the designed piston was proposed.