Vapor film-rupturing agent, and thermal treatment oil composition

A thermal treatment oil composition, comprising:

• a vapor film-rupturing agent comprising an asphaltene component, an aromatic component, a resin component, and a saturated hydrocarbon component;
• and
• a base oil,
• wherein the vapor film-rupturing agent is derived from asphalt as a starting material, the vapor film-rupturing agent comprising a fraction (x) (% by mass) of the saturated hydrocarbon component and a fraction (y) (% by mass) of the asphaltene component based on the total fraction 100% by mass of the saturated hydrocarbon component, the asphaltene component, the aromatic component, and the resin component,
• wherein fractions (x) and (y) are obtained by any one of analysis methods described in the Japan Petroleum Institute Standard and Manuals Testing Method for Petroleum Products JPI-5S-70-10 and the British Standard Test Method IP-469 that satisfies one or more of the following conditions (1) to (3):
• condition (1):
• a value T calculated from the following calculation expression (1) is 2.4000 or less, wherein x (% by mass) represents the fraction (x) of the saturated hydrocarbon component, and y (% by mass) represents the fraction (y) of the asphaltene component:
• T=1.2926×x/100−8.113×y/100+2.3384;
• Calculation expression (I):
• condition (2):
• the fraction (y) of the asphaltene component is 7.0% by mass or more;
• and
• condition (3):
• a ratio ((y)/(x)) of the fraction (y) of the asphaltene component and the fraction (x) of the saturated hydrocarbon component is 0.5 or more.