20CrMnTi齿轮钢在加工过程中经常会出现裂纹，通过对产生裂纹的部位进行宏观和微观检验，对常见的由铸坯缺陷引起的20CrMnTi钢加工开裂的特征进行了分析。结果表明: 由铸坯表面皮下气泡产生的裂纹，裂纹表面光滑，裂纹尾部圆钝，裂纹两侧有严重的氧化脱碳现象; 由铸坯表面夹渣引起的缺陷，裂纹处夹杂物和增碳并存，裂口区域晶粒有明显的方向性; 铸坯内部存在较多夹杂物会使得材料在加工过程中产生表面发纹缺陷。

Cracks were often found in 20CrMnTi gear steel during processing. The cracking characteristics of 20CrMnTi gear steel caused by casting defects were analyzed by means of macro and micro examination. The results indicate that the cracks caused by subsurface bubble on the casting surface were smooth, the crack tail was obtuse, and severe oxidation decarburization phenomenon occurred at both sides of the cracks. At the cracking area caused by surface slag, crackle inclusions and carburet coexisted and grain at the cracking area had obvious directivity. More inclusions in the casting blank would result in tiny surface cracks defect on surface of the material during processing.