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A Study for Production of Bimetal Rods and Powder-Packed Metal Tubes

双金属棒和粉末包装金属管生产的研究

基本信息

批准号：
63550510
负责人：
ONODERA Ryuta
金额：
$ 1.34万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

Three subjects were studied;(1) effects of relative strength (Y_A/Y_B) and relative size of core (r_A/r_B) and extrusion ratio (R) on the workability of bimetal rods with hard core (A) and soft sleeve (B) (2) effect of working method on the workability of powder-packed metal tubes and (3) numerical analysis for deformation of bimetal rods during extrusion.(1) Workability of bimetal rods: The experiments were carried out using Al alloys and copper as core material and aluminum and lead as sleeve (Y_A/Y_B=3-12), ranging from .3 to .9 of R_A/r_B. (a) The effect of R was not remarkable if R>1.5, but in the range of R>1.5 the decrease of R was of advantage to proportional (sound) extrusion of the rod with small r_A/r_B. (b) The proportional extrusion was more easily done for medium value of r_A/r_B than for small of large value. (c) The fracture mode for small value of r_A/r_B was periodic necking of core and that for large value was cracking of sleeve.(2) Workability of powder-packed metal tubes: Three types of metal working, namely, hydrostatic extrusion, swaging and roller dies drawing were done on 6 mm Ag tube (1mm thickness) filled by alumina powder (<.3 m dia.). The proportional forming was carried out in hydrostatic extrusion and swaging, but cracking of sleeve was occasionally observed in roller dies drawing, which will be attributed to change of the sectional shape of tube to ellipse.(3) Numerical analysis: Under some assumptions the strain distribution of core along the longitudinal direction was estimated by the variation method, which should give the minimum deformation energy for a given extrusion increment. The shape of core in extruded rod was determined by the strain distribution. The results of simulation has good agreement with experimental result.

三个受试者被研究；(1)相对强度(Y_A/Y_B)、芯材相对尺寸(R_A/R_B)和挤压比(R)对硬芯(A)和软套(B)双金属棒可加工性的影响；(2)加工方法对粉末填充金属管可加工性的影响；(3)双金属棒挤压变形的数值分析。(1)双金属棒的加工性：以铝合金和铜为芯材，铝和铅为套筒(Y_A/Y_B=3-12)，R_A/R_B为0.3~0.9。(A)若R&GT；1.5，但在R&GT；1.5范围内，R的减小有利于小r_A/r_B的棒材的比例(声音)挤压。(B)r_A/r_B的中值比小的或大的值更容易进行比例挤压。(2)粉末填充金属管材的加工性能：对厚度为1 mm的6 mm银管进行静液挤压、模锻和辊模拉拔三种金属加工。在静液挤压和模锻过程中采用比例成形，但在辊模拉拔过程中偶尔会出现套筒开裂现象，这是由于筒体截面形状变为椭圆形所致。(3)数值分析：在一定的假设条件下，用变分法估计芯子沿纵向的应变分布，对于给定的挤压增量，应给出最小的变形能。挤压杆中芯子的形状由应变分布决定。模拟结果与实验结果吻合较好。