| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a screw equivalent to a chemically-polished screw at a low cost with the same number of processes as that of the regular screw by forging the screw simultaneously roll-thread rolling using a chemically- polished thread rolling tool. SOLUTION: Projecting threads are approximately parallel to each other in a form rolling surface of a thread rolling tool, and preferably chemically polished in manufacturing a thread rolling die. The thread rolling die is preferably and chemically polished by stainless steel chemical abrasive glossy material. After a head part is formed in a rolling process, threads are formed using the thread rolling die, and at the same time, the surface of the screw is forged by the thread rolling die, and the surface is heat treated, oil during the machining is incinerated, and the oil on the screw surface is chemically removed by the pickling, burrs and chips are removed in the barrel treatment, and cleaned with water for finishing. The cost is reduced since the chemical polishing treatment need no large equipment such as the buffing or electrolytic polishing.
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