冷轧对Fe-Al合金层组织及高温氧化性能的影响

Influence of cold rolling on microstructure and high-temperature oxidation resistance of Fe-Al alloyed layer

利用热浸镀铝后真空扩散的方法在Q235钢板表面制备FeAl合金层,并进行形变量为20.5%、34.1%、40.9%的冷轧试验。采用金相、SEM、EDS、XRD分析了冷轧前后合金层的组织结构,测试了不同冷轧形变量试样的高温抗氧化性能。结果表明,冷轧后合金层与基体结合良好,未出现脆裂、剥落。冷轧过程中剧烈的塑性变形使FeAl相发生部分无序化转变,微观应变随冷轧形变量的增大缓慢增大,最大微观应变达0.40%。冷轧后合金层依然具有良好的高温抗氧化性能,经最大冷轧形变量40.9%时,高温抗氧化性能仅下降8.4%。

FeAl alloyed layer on Q235 steel was prepared by hot dip aluminizing and diffusion treatment in vacuum.The microstructure of FeAl alloyed layer on Q235 steel specimens cold rolled with different reductions（20.5%,34.1% and 40.9%） was analyzed by optical microscope,SEM,EDS and XRD.The high-temperature oxidation resistance of the specimens was examined.The results show that metallurgical bonding between the FeAl alloyed layer and Q235 steel substrate is obtained and no fracture and delamination of the layer is found after cold rolling process.The long range order of FeAl intermetallics phase is destroyed during the cold rolling process and the microstrain slowly increases as the cold rolling reduction rises.The microstrain increases to a peak value（0.4%） at cold rolling reduction of 40.9%.The FeAl alloyed layer still exhibits excellent high-temperature oxidation resistance after the cold rolling processing.The weight gain increases by 8.4% for the specimen subjected to 40.9% cold rolling reduction compared with that without cold rolling during high temperature oxidation testing.