Carbon steel for a rack bar and a method for manufacturing the same
AssigneesHyundai Motor Company, Kia Motors Corporation, Hyundai Steel Company
InventorsHyung Gook Lee, Jae Han Lim
Life of this patent
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Abstract
Carbon steel for a rack bar contains 0.50 to 0.55% by weight of carbon (C), 0.15 to 0.35% by weight of silicon (Si), 0.75 to 0.95% by weight of manganese (Mn), 0.025% by weight or less of phosphorus (P), 0.025% by weight or less of sulfur (S), 0.65 to 0.85% by weight of chrome (Cr), 0.20% by weight or less of molybdenum (Mo), 0.001 to 0.02% by weight of aluminum (Al), 5 to 50 ppm of boron (B), and iron (Fe) as a remainder and unavoidable impurities. A method for manufacturing the rack bar includes quenching, tempering, and drawing the carbon steel and warm forging the drawn carbon steel.
Claims11
A carbon steel for a rack bar, the carbon steel consisting of:
- 0.50 to 0.55% by weight of carbon (C);
- 0.17 to 0.32% by weight of silicon (Si);
- 0.78 to 0.88% by weight of manganese (Mn);
- 0.025% by weight or less of phosphorus (P);
- 0.025% by weight or less of sulfur (S);
- 0.70 to 0.80% by weight of chromium (Cr);
- 0.001 to 0.05% by weight of molybdenum (Mo);
- 0.003 to 0.015% by weight of aluminum (Al);
- 10 to 30 ppm of boron (B);
- 0 to 0.10% by weight of copper (Cu);
- 0 to 0.30% by weight of nickel (Ni);
- and
- iron (Fe) as a remainder and unavoidable impurities.
Dependencies are inferred from the claim text.