Heat-treatment oil composition

A method for producing a heat treating oil composition, comprising:

• mixing one or more of abase oil (A) selected from the group consisting of a mineral oil (A1), a synthetic oil (A2), and a vegetable oil (A3), a sulfur compound (B), and a carboxylic acid-based compound (C),
• the sulfur compound (B) containing one or more selected from the group consisting of a sulfide compound (B1) represented by the following general formula (b1), a sulfide compound (B2) represented by the following general formula (b2), a sulfide compound (B3) represented by the following general formula (b3), and a sulfide compound (B4) represented by the following general formula (b4), and
• the carboxylic acid-based compound (C) being one or more selected from the group consisting of a compound having at least one carboxy group, and an anhydride thereof:
• wherein
• in the general formula (b1), Ar11 each independently represents an aryl group having 6 to 15 carbon atoms having at least a hydroxy group, and R11 represents a substituted or unsubstituted hydrocarbon group (X1), in which the hydrocarbon group (X1) is an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 1 to 15 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, a cycloalkenyl group having 3 to 15 carbon atoms, a cycloalkylalkyl group having 4 to 15 carbon atoms, a cycloalkenylalkyl group having 4 to 15 carbon atoms, an aryl group having 6 to 15 carbon atoms, or an arylalkyl group having 7 to 15 carbon atoms,
• in the general formula (b2), Ar12 represents an arylene group having 6 to 15 carbon atoms having at least a hydroxy group, and R12 and Ru each independently represent a substituted or unsubstituted hydrocarbon group (X2), in which the hydrocarbon group (X2) is an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 1 to 15 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, a cycloalkenyl group having 3 to 15 carbon atoms, a cycloalkylalkyl group having 4 to 15 carbon atoms, a cycloalkenylalkyl group having 4 to 15 carbon atoms, an aryl group having 6 to 15 carbon atoms, or an arylalkyl group having 7 to 15 carbon atoms,
• in the general formula (b3) Ar13 represents an aryl group having 6 to 15 carbon atoms having at least a hydroxy group, and Ar14 represents a substituted or unsubstituted aryl group having 6 to 15 carbon atoms, and
• in the general formula (b4), Ar15 and Ar16 each independently represent a substituted or unsubstituted aryl group having 6 to 15 carbon atoms.