孔径比为2.50～3.00的自由锻冲孔坯料形状研究

Billet shape research of open punching with aperture ratio from 2.50 to 3.00

为消减圆柱坯料自由锻冲孔工件的"走样"缺陷,且高度保持与圆柱坯料冲孔相当,以Φ60mm×55mm坯料为例,取孔径比为2.50,2.75和3.00,通过Deform-3D软件模拟,得到预成形坯料形状为:外围高度需增加9.1%～3.8%,上端需做出与对应冲子直径之比为27.1%～24.0%的凸起,上端外径基本不变,下端外径需减小14.2%～9.3%,上下端之间呈卡腰状。用预成形坯料冲盲孔及冲穿孔,形状精度明显提高(孔径比为2.50时冲盲孔,工件上端面平面度由6.3mm提高到0.6mm,外侧表面圆柱度由5.9mm提高到0.4mm)。最后进行了物理模拟实验验证,可为实际生产应用提供参考。

In order to reduce the cylindrieaI billet deformation defects in open punching process and keep its workpiece height nearly unchanged, taking the Ф60mm× 55 mm cylindrical billet as an example, the billet was punched with dif ferent aperture ratio of 2.50, 2.75 and 3.00 using the Deform-3D software, and the preform billet shape was got that 9. 1%- 3.8% increase is needed in the outside height, a convex top surface with 27. 1%- 24. 0% height compared to the corresponding punch diameter is needed in the top surface whose diameter is unchanged, 14. 2%- 9.3% decrease is needed in the bottom surface diameter, and a waist-like side surface is obtained between the top and the bottom sur face. All of the blind hole and the through hole workpieces were improved obviously in the shape accuracy when punc hing the preform billet （the aperture ratio is 2.50, the blind hole workpiece has a flatness of 0.6 mm and cylindricity of 0.4 mm compared to the cylindrical workpiece of 6. 3 mm and 5.9 mm respectively）. The results were proved by ex- periment, which can provide references for the practice.