Steel material, crankshaft, and automobile component

An automobile component obtained by hot-forging and nitrocarburizing a steel material comprising, in terms of % by mass:

• C:
• 0.20% to 0.35%;
• Si:
• 0.01% to 0.35%;
• Mn:
• 0.55% to 1.50%;
• Cu:
• equal to or less than 0.60%;
• Ni:
• equal to or less than 0.30%;
• S:
• 0.01% to 0.15%;
• Cr:
• 0.01% to 0.20%;
• Mo:
• 0.01% to 0.05%;
• s-Al:
• equal to or less than 0.020%;
• Ti:
• 0.015% to 0.040%;
• N:
• 0.003% to 0.030%;
• Ca:
• 0.0003% to 0.0060%;
• and
• O:
• equal to or less than 0.010%,
• with the balance being Fe and unavoidable impurities,
• wherein 0.43≤Expression 1≤0.70 is satisfied in a case where Expression 1=[C]+0.07×[Si]+0.16×[Mn]+0.19×[Cu]+0.17×[Ni]+0.20×[Cr]+0.40×[Mo] is established,
• 0.38≤Expression 2≤0.70 is satisfied in a case where Expression 2=0.55×[C]+0.06×[Si]+0.18×[Mn]+0.09×[Cu]+0.47×[Mo]+[Cr] is established, and
• 1.77≤Expression 3≤3.0 is satisfied in a case where Expression 3=11×[Ca]/([N]+1.5×[O]) is established, and
• in which each [ ] in Expressions 1 to 3 indicates a content of the element shown therein in terms of % by mass, and
• wherein, in a case where S0 represents an entire number (number/mm2) of sulfides having a diameter of equal to or greater than 1.5 μm within 1 mm2 of a cross section parallel to a rolling direction, S1 represents a number (number/mm2) of sulfides which have a diameter of equal to or greater than 1.5 μm within 1 mm2 of the cross section parallel to the rolling direction and which contain Ca, and Expression
• 4=S1/S0 is established, Expression 4≥0.15 is satisfied.