The effects of Al addition on austenite grain growth and particle characterization in heat-affected zone during high-heat-input welding for Mg- deoxidized steel plates without Al (0Al) and with 0.02wt-% Al (200Al) were studied. Austenite grains grow intensively in 1300–1400 °C and TiN particles play the role on inhibiting grain growth. The number density and average size of submicron and nanometer particles decreases and increases, respectively with Al addition. There are critical dissolved particle sizes of 1.84, 3.18 and 11.64 nm at 1300, 1350 and 1400 °C, respectively. The dissolution of nanoparticles in 0Al larger than that in 200Al causes the faster reduction rate of pinning force and greater increase of grain growth rate in 0Al. The effect of submicron particle coarsening on austenite grain growth is non-obvious because the amount of submicron particles is less than that of nanoparticles and the submicron particle coarsening is a comparatively slow process.

研究了铝添加量为0.02wt％的铝（200Al）对镁脱氧钢板进行高热输入焊接时，铝添加量对热影响区奥氏体晶粒长大和颗粒特征的影响。奥氏体晶粒在1300-1400°C时集中生长，而TiN颗粒起抑制晶粒生长的作用。随着Al的添加，亚微米和纳米颗粒的数量密度和平均尺寸分​​别减小和增大。在1300、1350和1400°C下，临界溶解粒径分别为1.84、3.18和11.64 nm。纳米粒子在0Al中的溶出大于200Al中的溶出，导致钉扎力的减小速率更快，而0Al中的晶粒生长速率增大更大。