某6Cr13马氏体不锈钢板经过三道冷轧工序后静置一周出现密集分布的微裂纹，通过对钢板的化学成分、显微组织、表面形貌、硬度、微区成分等进行分析，确定了微裂纹产生的原因。结果表明：由于原材料钢板局部碳化物中的铬含量过高，导致周边出现贫铬区域，从而降低了材料的耐腐蚀性能，当接触到氯离子时，贫铬区出现孔腐蚀；随着腐蚀的发展，孔内氯化物浓缩、水解等使得孔内介质pH下降成为酸性溶液，氢离子通过电化学反应获得电子后成为氢原子并在局部富集产生氢压；在氢压与轧制残余应力的共同作用下钢板沿着轧制方向产生氢致裂纹。最后根据微裂纹产生原因提出了延长退火时间、改善成分等建议。

After three times of cold-rolling process and standing for a week, densely distributed micro-cracks appeared in the 6Cr13 martensitic stainless steel plate. The crack forming causes were determined by analyzing the chemical composition, microstructure, surface morphology, hardness and micro-zone compositions of the steel plate. The results show that due to the high chromium content in the local carbides of the raw material, the phenomenon of poor chromium appeared in the carbides periphery, which reduced the corrosion resistance of the material. When the steel plate was exposed to chloride ions, pitting corrosion of the chromium deficient area occurred. With the development of the corrosion, the pH of the pit medium reduced to acidic because of the concentration and hydrolysis of chlorides in the pits. Hydrogen ions obtained electrons and became hydrogen atoms by electrochemical reaction, and then the hydrogen atoms enriched at the local position and produced hydrogen pressure. Under the combined action of hydrogen and rolling residual stress, hydrogen-induced cracking occurred along the rolling direction. Finally, according to the formation causes of micro-cracks of the steel plate, suggestions such as lengthening annealing time and improving compositions were proposed.