PROCESS AND SCRAPING TOOL FOR MANUFACTURING HIGH-STRENGTH STEEL WIRE SERVING AS BASE MATERIAL MAINLY FOR ROLLING ELEMENTS, ROLLER BEARINGS AND OTHER DETAILS EXPOSED TO HEAVY SURFACIAL LOADS

摘要

The drawing tool for high-strength steel rod prodn. esp. for the prodn. of bearing rolling elements and other machine parts subject to high surface loading. - The steel rod is first softened by heating in a neutral or reducing atmosphere to 770-810 deg. C. Scale is removed mechanically by shot-blasting or chemically in an 18% hydrochloric acid bath. The clean rod is drawn through a tool and stress relieved at 600-700 deg. C in a nitrogen gas protective atmosphere. Finally (depending on the application) the stress-relieved rod is provided with a minimum phosphate layer of 8 GR/M2 in a phosphate bath. If required, the phosphate layer is saturated with oil. The drawing tool (4) is provided with one or more wear resistant inserts (4a) having the required edge geometry (4f, 4c). The scraping surface (4b) slopes towards the front edge (4d).