0Cr17Ni4Cu4Nb钢锻造裂纹分析与控制

Analysis and control on forging cracks of steel 0Cr17Ni4Cu4Nb

针对0Cr17Ni4Cu4Nb不锈钢锻造生产过程中产生的锻造裂纹,对原材料和锻造工艺进行分析发现,产生裂纹的主要原因是由于材料内部组织中的δ铁素体含量超过一定量时,会极大地降低材料的锻造塑性,使得变形抗力增大;当变形量逐渐增加到一定量时,裂纹开始出现,并且随着变形量的增加裂纹越来越严重。研究结果表明,在使用该材料时,需要对原材料进行铁素体含量检查并加以控制,铁素体含量要求〈20%,符合CB/T 1209—1992 F7级以上标准,保证该材料良好的热加工工艺塑性;毛坯粗糙度要求达到Ra=1.6-0.8μm以上,预热锻造工具,严格控制每一火次的锻造变形量,以满足锻件的设计和质量要求。

For raw materials and forging technology of stainless steel 0Cr17Ni4Cu4 Nb,it was found that the main reason for cracks produced in forging was the excessive amounts of the delta ferrite in material internal microstructure. When the content of delta ferrite exceeded a certain amount,the forging plasticity of material significantly decreased and the deformation resistance increased. Once deformation gradually increased to a certain amount,the cracks appeared,and became more serious with the increase of deformation. Research results show that check and control the content of delta ferrite in raw materials before using to ensure that the materials still have good plasticity in the hot working process and the ferrite content is less than 20% and meets or above the standard of F7 level of CB / T 1209—1992. At the same time roughness of the blank must achieve above Ra1. 6 μm- Ra0. 8 μm and the forging tools should be preheated and the forging deformation of each heat should be strictly controlled to satisfy the requirement of design and quality of forgings.