Fine graphite uniform dispersion steel excellent in cold machinability, cuttability and hardenability, and production method for the same

A method for producing fine graphite uniform dispersion steel excellent in cold workability, cuttability and hardenability, and containing 0.3 to 1.0% by weight of graphite particles having a mean particle diameter of not more than 4.0 .mu.m and being present in a distribution of at least 3,000 per mm.sup.2, said method comprising:

• cooling a steel comprising, in terms of percent by weight, as the basic components,
• C:
• 0.30-1.0%,
• Si:
• 0.4-1.3%,
• Mn:
• 0.3-1.0%,
• P:
• .ltoreq.0.03%,
• S:
• 0.010-0.055%,
• Al:
• 0.01-0.10%,
• B:
• 0.0003-0.006%,
• N:
• 0.002-0.010%
• Mo:
• 0.05-0.20%,
• and the balance consisting of Fe and unavoidable impurities, immediately after hot rolling, by a water cooling apparatus disposed at the back of a hot rolling line at a cooling start temperature of not less than A.sub.rl point, a cooling finish temperature of not more than M.sub.s point and a mean cooling rate of 5.degree. to 100.degree. C./s;
• further cooling said steel naturally;
• and then
• conducting graphitization treatment at a heating temperature of 600.degree. to 720.degree. C.