HIGH STRENGTH AND TOUGHNESS SPRING HAVING EXCELLENT FATIGUE LIFE, STEEL WIRE ROD AND STEEL WIRE FOR THE SAME AND PRODUCING METHOD OF SAID STEEL WIRE AND SPRING

摘要

Provided are a high strength and high toughness spring having an excellent fatigue life, a steel wire rod and a steel wire for the spring, and a method for producing the steel wire and the spring. The steel wire rod includes approximately Q5 wt% to approximately Q7 wt% of carbon, approximately 1.5 wt% to approximately 3.0 wt% of silicon, approximately Q3 wt% to approximately 1.0 wt% of manganese, approximately QOl wt% to approximately 1.5 wt% of chromium, approximately QOl wt% to approximately 1.0 wt% of molybdenum, approximately QOl wt% to approximately 1.0 wt% of nickel, approximately Q005 wt% to approximately QO 15 wt% of boron, approximately Q0015 or less wt% of oxygen, approximately QOl or less wt% of aluminum, approximately Q02 or less wt% of phosphorous, approximately Q02 or less wt% of sulfur, and approximately Q02 or less wt% of nitrogen.