Non-quenched and non-tempered steel wire rod for hot forging with excellent machinability and impact toughness and method for manufacturing same

A method for manufacturing a non-quenched and non-tempered steel wire rod with improved machinability and impact toughness, the method comprising:

• reheating a steel piece comprising, in percent by weight (wt %), 0.3% to 0.5% of C, 0.4% to 0.9% of Si, 0.5% to 1.2% of Mn, 0.02% or less of P, 0.01% to 0.05% of S, 0.01% to 0.05% of sol.Al, 0.1% to 0.3% of Cr, 0.01% to 0.02% of Ti, 0.0005% to 0.002% of Ca, 0.007% to 0.02% of N, and the balance of Fe and inevitable impurities, and including ferrite and pearlite as a microstructure in a temperature range of 950° C. to 1120° C.;
• finish rolling the reheated steel piece into a steel wire rod at a temperature of 750° C. to 850° C.;
• and
• winding and cooling the steel wire rod,
• wherein the cooling performed after the winding comprises a process of cooling to 400° C. at an average cooling rate of 0.1° C./s to 5.0° C./s, wherein the steel wire rod includes ferrite and pearlite as a microstructure, Relational Expression 1 is satisfied, and an area fraction of MnS is 0.10% to 0.60%:
• 20
• ≤
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• Mn
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• /
• [
• S
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• ≤
• 70.
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• Relational
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• Expression
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• 1
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