薄带连铸304不锈钢碳化物析出及溶解过程的原位观察

 采用激光共焦扫描显微镜原位观察薄带连铸304不锈钢高温下碳化物的析出及溶解过程。结果表明，薄带连铸304不锈钢在600 ℃开始析出碳化物，首先从晶内析出，而后从晶界析出，碳化物析出量随温度升高逐渐增加，到900 ℃时，析出量最大；1 006 ℃时，碳化物开始溶解，1 049 ℃时，大部分碳化物迅速溶解，1 155 ℃时，碳化物完全分解溶入基体，其溶解过程为δ→M23C6+δ′→γ。碳化物析出与薄带连铸铸带凝固组织及后续冷却过程有关。

In-Situ Observation of Carbide Precipitation and Dissolution in Strip Cast 304 Stainless Steel

The carbide in 304 stainless steel has great effect on the strip performance in strip casting process. The carbide precipitation and dissolution were in situ observed using a confocal scanning laser microscope in strip cast 304 stainless steel. It was found that carbide precipitating started at 600 ℃, first in grain interior, then in grain boundary, and carbide quantity increased with increasing the temperature, at 900 ℃reached its maximum quantities. The carbide was dissolved at 1 006 ℃; at 1 049 ℃ most carbide dissolved rapidly and at 1 155 ℃ dissolved completely. The principle of carbide precipitation and resolution is δ→M23C6+δ′→γ, which is related with the solidification microstructure and cooling process of strip casting.