F55双相不锈钢方形阀体锻造工艺优化  

Optimization on forging process of square valve body for F55 duplex stainless steel

作　　者：孙常奋 Sun Changfen(Comprehensive Technology Research Institute,Hudong Heavy Machinery Co.,Ltd.,Shanghai 200129,China)

机构地区：[1]沪东重机有限公司综合技术所,上海200129

出　　处：《锻压技术》2021年第6期54-57,共4页Forging & Stamping Technology

基　　金：工信部船用低速柴油机原理样机研制资助(CDGC01-KT0103)。

摘　　要：通过分析F55双相不锈钢中的氮在锻造温度范围内的固溶、析出机理来改进锻造工艺,以解决大规格F55双相不锈钢的锻后坯件的表面裂纹及加工后表面延迟开裂的问题。沿晶界析出的氮难以再次固溶于组织,从而形成较大内应力。在锻造变形过程中,拉应力促进了组织中氮的析出,压应力阻止并促使析出的氮向组织扩散,因此,在锻造过程中应控制坯件内部的应力状态,使之处于压应力状态,避免了坯件内部存在过多的非变形区及微变形区。锻造时采用"V"形砧座是一项有效措施,同时,采用先小变形、后大变形的方式,改变了内部变形应力状态,有效地避免了当圆形截面锻为方形时内部形成的拉应力较大的问题,"V"形砧座的夹角为135°时,坯件内部的压应力状态最佳。The forging process was improved by analyzing the solid solution and precipitation mechanism of nitrogen in F55 duplex stainless steel in the forging temperature range to solve the problems of surface cracks of the blank after forging and delayed surface cracking after processing of large-size F55 duplex stainless steel, and the nitrogen precipitated along the grain boundary was difficult to dissolve in the structure again resulting in a large internal stress. Then, during the forging deformation process, the tensile stress promoted the precipitation of nitrogen in the structure, and the compressive stress prevented and promoted the diffusion of precipitated nitrogen into the structure. Therefore, the internal stress state of blank should be controlled during the forging process to make it in a compressive stress state, and the excessive non-deformation zone and micro-deformation zone inside the blank were avoided. In addition, the use of "V"-shaped anvil was an effective method when forging. At the same time, the method of the first small deformation and then large deformation changed the internal deformation stress state and effectively avoided the large tensile stress formed inside when the circular section was forged into a square shape. Finally, when the included angle of "V"-shaped anvil was 135°, the internal compressive stress state of blank was the best.

关 键 词：双相不锈钢 阀体 Α相 Γ相 变形区 

分 类 号：TG316.2[金属学及工艺—金属压力加工]