| 摘要 |
PURPOSE:To manufacture a clad bar material free from cracking of covering material and opening between covering metal and base metal, by determining sectional dimension of the base metal, inner diameter of the covering metal and formed thickness to make average percentage of elongation in the direction of flat of covering metal after forming within a specified range. CONSTITUTION:A bar base metal 1 made of electric conductive metal or alloy having circular sectional form is inserted into a tubular covering metal 2 made of anti-corrosion metal or alloy, and placed between dies 4, 5 and pressed. Then, the base metal fills up inside of the covering material 2, but the covering material is little elongated at this point of time. When pressed further, R part 2b of the covering metal 2 is flattened. At the same time, flat parts 2a are elongated and thickness is reduced, and a desired clad bar metal having flat parts 2a' is obtained. In this case, sectional dimension of the base metal 1, inner diameter of the covering metal and formed thickness are determined to make average percentage of elongation more than 5% and less than allowable percentage of elongation of the material. Little elongation occurs in R part 2b, and initial thickness is retained. |
