退火露点对TWIP钢选择性氧化及可镀性的影响

Effect of annealing dew point on selective oxidation and galvanizability of TWIP steel

以TWIP钢为研究对象,在不同露点和温度下进行退火-镀锌试验,采用FE-SEM、EDS能谱仪和EPMA对退火试样进行分析,并与镀锌效果对照,得到退火气氛对可镀性的影响。试验结果表明:在两种退火温度下,露点为-50℃时,氧势低,极少量的Mn发生外氧化,热镀锌效果较好;随着露点升高,氧势升高,表面生成更多膜状和颗粒状Mn的氧化物,可镀性变差;而氧势足够高时,致使部分Mn发生内氧化,表面覆盖少量的块状Mn的氧化物,且有Al的氧化物出现,镀锌效果最好。

Annealing and hot-dip galvanizing experiment was carried out on TWIP steel at different annealing temperatures and dew points,and the experimental results of the hot dip galvanizing were investigated by FE-SEM,EDS spectrometer and EPMA. By comparing zinc coating and oxide layer,effect of annealing atmosphere on the galvanizability was determined. The results show that the oxygen potential is low in two kinds of annealing temperature at the dew point of- 50 ℃,a very small amount of Mn is oxidized externally and the galvanizability is good; With the increase of dew point,the oxygen potential increases,more membranous and granular oxides of Mn generate on the surface,and the galvanizability is poor. And when the oxygen potential is high enough so that Mn is partial oxidized internally,a small amount of Mn blocky oxides appear on the surface with some Al oxides,and the galvanizability is the best.