Patent ID: 7081174

Claim:
A process for producing a titanium(Ti)-containing steel product for carburizing, said process comprising the steps of: providing an ingot or bloom comprising a steel comprising, by weight, carbon (C): 0.10 to 0.45%, silicon (Si): 0.03 to 1.0%, manganese (Mn): 0.2 to 2.0%, titanium (Ti): 0.05 to 0.2%, aluminum (Al): 0.005 to 0.05%, and nitrogen (N): not more than 0.01% with the balance consisting of iron (Fe) and unavoidable impurities; and subjecting said steel ingot or bloom to a series of hot working steps including the steps of: (a) rolling the steel ingot or bloom into a semi-finished steel product, (b) rolling the semi-finished steel product into a steel bar or wire rod, and (c) forging the steel bar or wire rod into a product, wherein, in said series of hot working steps, said steel is given a thermal history which may take place in any order during the working steps (a) to (c), said thermal history comprising the steps of: (i) at least once heating said steel to 1,250° C. or above, (ii) cooling to room temperature, and (iii) reheating to a temperature range of 800 to 1,100° C., and cooling the steel product after said series of hot working steps, wherein the steel product is cooled from 800° C. to 500° C. at an average cooling rate of not more than 5° C./sec to bring the hardness of the steel product after the hot working to not more than 100 HRB.