FGH96合金反复镦拔与挤压缺陷对比分析

Comparative Analysis on Defects in Repeated Upsetting and Stretching Deformation with Extrusion Deformation of FGH96 Alloy

对FGH96合金反复镦拔变形与挤压变形两种制坯工艺的夹杂缺陷水平进行了比较,并分析了不同变形状态下非金属夹杂物的形变特性。结果表明:反复镦拔变形后,锻件内检测到的非金属夹杂物数量有不同程度的增多,超标缺陷成倍增长;而FGH96合金挤压+等温锻造变形后,锻件内检测到的非金属夹杂物数量明显减少,纯净度水平有大幅提高。从微观夹杂物形貌的变形特性来看,等温锻造变形时在垂直于变形方向合金中夹杂物缺陷的尺寸增大;反复镦拔变形时,合金中原有非金属夹杂物缺陷聚集使可检测到的缺陷面积增大;而在挤压变形过程中,夹杂物缺陷在挤出方向被拉长成不连续的线状,每个方向上夹杂物的面积均减小;FGH96合金挤压+等温锻造变形后夹杂缺陷的大小主要由挤压变形后夹杂缺陷破碎情况决定;因此大挤压比变形可有效破碎合金中非金属夹杂物,改善锻件质量。

The inclusion defects in repeated upsetting and stretching deformation and hot extrusion （HEX） deformation of FGH96 alloy were compared and the deformation characteristics of non-metallic inclusions were studied. The results show that the quantity of non-metallic inclusions which can be detected in forging increases variously and over-standard defects are multiplied in repeated upsetting and stretching process of FGH96 alloy. Moreover, the quantity of non-metallic inclusions which can be detected in forging reduces obviously and cleanliness level rises largely in HEX＋ HIF（Hot Isothermal Forging） process of FGH96 alloy. The sizes in the direction perpendicular to deformation of nonmetallic inclusions increase in isothermal forging process. The non-metallic inclusions in repeated upsetting and stretching process get together and areas of inclusions increase. The non-metallic inclusions are pulled into a discontinuous line in extrusion direction and areas of inclusions in each direction are constricted in extrusion process of FGH96 alloy. The deformation characteristics of inclusions in HEX＋ HIF process of FGH96 alloy is conditioned by the state of the inclusions in extrusion process. In summary, extrusion process of large extrusion ratio can break the non-metallic inclusions in FGH96 alloy effectively and improve forging quality.