Non-heat treated steel for crankshafts and crankshaft using non-heat treated steel

A non-heat treated steel for a crankshaft, wherein the non-heat treated steel for a crankshaft comprises:

• iron (Fe),
• 0.39 to 0.42 mass % of carbon (C),
• 0.15 to 0.35 mass % of silicon (Si),
• 0.90 to 1.30 mass % of manganese (Mn), and
• 0.08 to 0.15 mass % of vanadium (V);
• and
• a content of phosphorous (P) is 0.030 mass % or less,
• a content of copper (Cu) is 0.300 mass % or less,
• a content of nickel (Ni) is greater than 0 and 0.30 mass % or less, and
• a content of chromium (Cr) is 0.35 mass % or less;
• and
• wherein the non-heat treated steel for a crankshaft further comprises:
• 0.010 to 0.035 mass % of sulfur (S), and
• 0.02 to 0.05 mass % of bismuth (Bi).

A non-heat treated steel for a crankshaft, wherein the non-heat treated steel for a crankshaft comprises:

• iron (Fe),
• 0.37 to 0.43 mass % of carbon (C),
• 0.20 to 0.30 mass % of silicon (Si),
• 0.90 to 1.30 mass % of manganese (Mn), and
• 0.08 to 0.15 mass % of vanadium (V);
• and
• a content of phosphorous (P) is 0.030 mass % or less,
• a content of copper (Cu) is 0.300 mass % or less,
• a content of nickel (Ni) is greater than 0 and 0.30 mass % or less, and
• a content of chromium (Cr) is 0.35 mass % or less;
• and
• wherein the non-heat treated steel for a crankshaft further comprises:
• 0.010 to 0.035 mass % of sulfur (S), and
• 0.02 to 0.05 mass % of bismuth (Bi).