采用二次正交回归试验方法,研究了 X70 管线钢热扩渗铝保温温度、扩渗时间与渗铝层厚度的关系,建立了渗层回归方程,得到 X70 管线钢最优的热扩渗铝工艺参数。 观察了 X70 管线钢热浸渗铝处理后的表面、界面微观形貌,分析了 Fe 和 Al 的含量沿渗层的变化情况,并对热浸渗铝过程中的元素扩散机理进行了探讨。 结果表明:渗铝层厚度随保温温度的升高和扩渗时间的延长而增大,适宜的保温温度为 950 ℃ ,扩渗时间为 6 h。

The relationship between hot diffusion aluminizing temperature, infiltration time and thickness of aluminized coating of X70 pipe line steel was researched by quadratic orthogonal regression testing method. The regression equation of the alloying layer thickness was established. The optimum process for hot diffusion aluminizing treatment was gotten. The surface and interface morphologies of X70 pipeline steel after the aluminizing treatment were observed, and Fe and Al content change by the carbonitride layer were analyzed. The element diffusion mechanism of hot dipping alumetizing process was discussed. The results show that alloying layer thickness is increased with the rising of insulation temperture and the extending of diffusion time. The ideal inoulation temperature is 950 ℃ and time is insulation 6 h.