渗铝Q235钢的渗层组织和抗高温氧化性能

分析了Q2 3 5钢热浸渗铝和铝硅合金层的显微组织 ,并对其抗高温氧化性能进行了研究。热浸渗层由镀层 (表层 )和化合物层 (内层 )两层组成 ,金相和X射线能谱分析 (EDS)结果表明纯铝渗层的化合物层呈厚齿状 ,由η相 (Fe2 Al5)组成 ;铝硅合金渗层的化合物层呈薄带状 ,由Si合金化的η相即Fe2 (Al Si) 5组成。热浸渗层经扩散退火后 ,表面镀层消失 ,渗层由表及里依次出现 η相、ζ相、β2 相、β1相和固溶体α相等过渡组织。 80 0℃高温氧化试验结果表明 ,渗纯铝Q2 3 5钢的抗高温氧化性能优于 1Cr1 8Ni9Ti不锈钢 ,硅的加入可以改善热浸工艺性能 ,但降低了渗层的抗高温氧化性能。

Microstructure and Anti-Oxidation Properties of Hot-Dip Aluminized Q235 Steel

The microstructure of the hot dip aluminized layer and aluminium silicon alloy layer of Q235 steel was analyzed,and the anti oxidation properties of the hot dip aluminized layer was studied. The hot dip aluminized layer was composed of coating (surface layer) and compound (inner layer).The analyses of metallurgy and EDS show that the compound layer of pure aluminized layer looked like a thick teeth composed of η phase( Fe 2Al 5),the compound layer of Al Si alloy layer looked like a thin belt composed of Fe 2(AlSi) 5. The surface coating disappeared after diffusion and annealing of the hot dip aluminized layer,some transition structures such as η phase,ζ phase,β 2 phase,β 1 phase,and solid solution α phase appeared one by one from the surface to the inner of the aluminized layer. The high temperature oxidation test shows that anti oxidation property of pure aluminized Q235 steel was better than that of 1Cr18Ni9Ti stainless steel. The hot dip technology could be improved by adding silicon,but the anti oxidation property of the aluminized layer was lowered.