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对表面贫钴的无η相WC-Co硬质合金进行渗碳热处理制备梯度硬质合金。通过正交试验探究了各工艺参数对梯度结构的影响;利用极差分析与方差分析法确定最佳渗碳工艺参数水平。结果表明:各工艺参数对梯度结构和贫Co幅度的影响程度依次是渗碳温度、甲烷体积分数、渗碳时间及混合气体流速。随渗碳温度的升高和渗碳时间的延长,梯度层厚度和贫Co幅度增大;随甲烷体积分数的增大,梯度层厚度和贫Co幅度减小;随混合气体流量的增加,梯度层厚度和贫Co幅度先增大、后减小;最终确定了合理的制备工艺参数,即渗碳时间t=120min,渗碳温度T=1 420℃,甲烷体积分数φ=1.5%,混合气体流量qV=8L·min-1。
Graded cemented carbide was prepared by carburizing heat treatment of non-n-phase WC-Co cemented carbide with poor surface. Through orthogonal test to explore the effect of process parameters on the gradient structure; using range analysis and analysis of variance to determine the optimum level of carburization process parameters. The results show that the influence of process parameters on the gradient structure and the extent of lean Co are followed by carburizing temperature, methane volume fraction, carburizing time and mixed gas flow rate. With the increase of carburizing temperature and carburization time, the thickness of gradient layer and the extent of poor Co increase. With the increase of methane volume fraction, the thickness of gradient layer and the amplitude of poor Co decrease. With the increase of mixed gas flow rate, the gradient The thickness of the layer and the amplitude of the Co-depleted layer first increased and then decreased. Finally, the reasonable preparation parameters were determined, that is carburizing time t = 120min, carburizing temperature T = 1 420 ℃ and methane volume fraction φ = 1.5% Flow qV = 8 L · min-1.