(Session 10A)DEVELOPMENTS OF MANUFACUTRERING STEEL WIRE RODS USED FOR HIGH STRENGTH WIRES

摘要

Recently, the Asia countries become important markets of various steel wires used for wire ropes, PC strands and so on. The steel wires are produced through the cold drawing of steel wire rods. Therefore, the market needs the wire rod with high drawability which can reduce the manufacturing cost of the wire making. In order to produce steel wire rods with high strength and good drawability, the patenting process, a kind of heat treatment, is known. The patenting consists of passing the wire through the tube in a furnace at about 900～1000°C,and in a molten lead or salt both for the subsequent cooling.　But the patenting process needs a large capital investment and decreases the productivity of the wire making. This report describes the manufacturing process of wire rods, called as KKP (Kobe-Kakogawa Patenting), which enables to produce high quality steel efficiently. The KKP is a developed process of controlled temperature with air cooling on the stelmor conveyor after hot rolling. The KKP wire has higher strength than the conventionally air-cooled steel, and longitudinal robust quality as well as patented wires. For larger size wire rods which is difficult to be cooled rapidly, high strength has been achieved by alloying element addition.