304Cu抗菌不锈钢热轧带钢边裂缺陷成因分析及改进措施

针对304Cu抗菌不锈钢热轧带钢边部开裂问题,通过微观组织及成分分布分析,对缺陷产生原因进行了研究。结果表明,304Cu热轧带钢边部裂纹分存在两种形貌,表面裂纹呈网格状,宽度约为30~70 μm,内部裂纹发生在表面下方1 mm范围内,内部裂纹中心存在20~40 μm孔洞,孔洞内部无非金属夹杂物等杂质。分析得到造成304Cu热轧带钢边裂的原因为Cr富集的高温铁素体与奥氏体基体发生高温组织不稳定变形,高温组织的不协调变形导致边部开裂。另外,Cu元素的富集降低了晶间结合力,也促进了内部孔洞的产生,进而加大了边裂缺陷的发生几率。因此,在保证冶炼成分稳定的条件下,通过调整热轧加热工艺,控制加热时间在190~210 min、加热温度在1 260~1 275 ℃的区间内,304Cu抗菌不锈钢热轧带钢边裂缺陷得到明显改善。

Cause analysis of edge cracking defects of 304Cu antibacterialstainless steel hot rolled strip and its countermeasures

Aiming at the edge cracking of 304Cu antibacterial stainless steel hot rolled strip, the causes of defects were studied by analyzing the microstructure and composition distribution. The results show that there are two morphologies in the edge cracks of 304Cu hot rolled strip. The surface cracks are grid-like with a width of about 30-70 μm. The internal cracks occur within 1 mm below the surface, and the center of the internal crack exists 20-40 μm hole, no non-metallic inclusions and other impurities inside the hole. It can be obtained that the main reason for the edge cracks of the 304Cu hot rolled strip is that the Cr-rich high-temperature ferrite and austenite matrix have unstable high-temperature structure deformation, and the uncoordinated deformation of the high-temperature structure causes edge cracking. In addition, the enrichment of Cu element reduces the intergranular bonding force, and also promotes the generation of internal holes, thereby increasing the probability of edge cracking. Therefore, under the condition of ensuring the stability of the smelting composition, by adjusting the hot rolling heating process, the heating time is 190-210 min and the heating temperature is 1 260-1 275 ℃, the edge crack defect of 304Cu hot rolled strip has been significantly improved.