电弧喷涂铝涂层模具钢内表面失效研究

Study on Surface Failure of Al Arc-spraying on Inner Surface of Mold Steel

研究了模具钢4Cr5W2Si V内表面电弧喷涂Al涂层的热疲劳和抗高温氧化性能。利用电子天平、扫描电镜(SEM)对实验处理后的试样质量变化和涂层截面情况进行微观观察和分析。结果表明:经820℃热循环后,电弧喷涂Al涂层模具钢的热疲劳性能有显著改善,涂层厚度较小,Al涂层具有较好的热疲劳性能,涂层厚度越大,疲劳强度越低;恒温600℃时,经电弧喷涂Al涂层处理的模具钢抗高温氧化性能显著提高。纯Al涂层在模具钢持续高温后随Al元素的扩散,模具钢Al含量不断增加,导致模具塑性降低、脆性增加,增大了模具失效的可能性。

Aluminum coating was prepared on the inner surface of 4Cr5W2SiV mold steel by electric arc spraying technology, and the thermal shock resistance and high temperature oxidation resistance were studied. The quality changes and coating cross-section of the processed were observed by electronic scales and SEM. The results show that the thermal shock resistance of the sprayed die steel with Al coating is significantly improved after 820 ~C thermal cycling. The Al coating has better property of thermal shock resistance when the thickness is smaller, on the contrary, the property is lower. The high temperature oxidation resistance of the sprayed die steel is also excellently enhanced at 600 ~C constant temperature. When the pure AI coating is processed via high temperature, the percentage of Al element in die steel continuously increases, the mold plastic reduces and brittleness increases with the Al diffusion, likely leading to mold failure.