ULTRA HIGH STRENGTH STEEL WIRE ROD HAVING HIGH RESISTANCE OF DELAYED FRACTURE, AND METHOD FOR MANUFACTURING THE SAME

摘要

PURPOSE: An ultra high-strength steel wire having improved delayed fracture resistance and manufacturing method thereof are provided to improve delayed fracture property by hydrogen. CONSTITUTION: A steel material is heated less than 1100 degrees Celsius. The heated steel material is hot-rolled at the temperature range of 900-1000 degrees Celsius. The rolled steel material is frozen to 600-650 degrees Celsius at the cooling speed of 5-10 degrees Celsius / s. The frozen steel material is cold-drawn at a reduction of 60-80%. The steel material comprises V of 0.02-0.1%. Precipitate multiplies pearlite intensity and acts to the trap site of diffusible hydrogen. The resistivity of the hydrogen delayed fracture is improved through the action.