Heat-treatment oil composition

Abstract

A heat-treatment oil composition can make it possible to achieve both high quenching hardness and reduced quenching distortion. A heat-treatment oil composition may include a base oil (A) and a vapor film rupturing agent (B). The heat-treatment oil composition may make it such that, on a cooling curve obtained in accordance with the cooling performance test method in JIS K2242:2012, the time in seconds to 300° C., e.g., the cooling time from 800 to 300° C., is less than 6 seconds. Component (B) may include a petroleum resin.

1 . A heat-treatment oil composition, comprising:
 a base oil (A); and   a vapor film rupturing agent (B) comprising a petroleum resin,   wherein, on a cooling curve obtained in accordance with a cooling performance test method of JIS K2242:2012, a number of seconds to 300° C., which is a cooling time from 800° C. to 300° C., is less than 6 seconds.   
     
     
         2 . The composition of  claim 1 , wherein a characteristic number of seconds obtained from the cooling curve is 1 second or more. 
     
     
         3 . The composition of  claim 1 , wherein a characteristic number of seconds obtained from the cooling curve is 2.5 seconds or less. 
     
     
         4 . The composition of  claim 1 , wherein the petroleum resin has a softening point of 40 to 150° C. 
     
     
         5 . The composition of  claim 1 , wherein the petroleum resin has a number-average molecular weight (Mn) of 200 to 5,000. 
     
     
         6 . The composition of  claim 1 , wherein the petroleum resin is a resin obtained by polymerizing or copolymerizing at least one unsaturated compound selected from an aliphatic olefin comprising 4 to 10 carbon atoms, an aliphatic diolefin, and an aromatic compound comprising an olefinic unsaturated bond and 8 or more carbon atoms. 
     
     
         7 . The composition of  claim 1 , wherein the petroleum resin is at least one selected from an aliphatic petroleum resin, an aromatic petroleum resin, an aliphatic-aromatic copolymerization-based petroleum resin, a dicyclopentadiene-based petroleum resin, a dicyclopentadiene-aromatic copolymerization-based petroleum resin, and a hydrogenated petroleum resin and modified petroleum resin thereof. 
     
     
         8 . The composition of  claim 1 , having a kinetic viscosity at 40° C. of 1 to 100 mm 2 /s. 
     
     
         9 . The composition of  claim 1 , wherein the base oil (A) comprises a low-viscosity base oil having a kinetic viscosity at 40° C. in a range of from 1 to 50 mm 2 /s and a high-viscosity base oil having a kinetic viscosity at 40° C. in a range of from greater than 50 to 550 mm 2 /s. 
     
     
         10 . The composition of  claim 1 , wherein the number of seconds to 300° C. is in a range of from 4 to 6 seconds. 
     
     
         11 . The composition of  claim 1 , wherein the petroleum resin is present in a range of from 0.1 to 90% by mass, based on total composition mass. 
     
     
         12 . The composition of  claim 1 , wherein the base oil (A) is present in a range of from10 to 99.9% by, mass based on total composition amount. 
     
     
         13 . The composition of  claim 1 , further comprising;
 a luster improving agent (C).   
     
     
         14 . A method for quenching a metal material, the method comprising:
 treating the metal material with the composition of  claim 1 .   
     
     
         15 . A method for producing the composition of  claim 1 , the method comprising:
 mixing the base oil (A) and the vapor film rupturing agent (B).   
     
     
         16 . The composition of  claim 1 , wherein the petroleum resin comprises, in polymerized form, an aliphatic olefin comprising 4 to 10 carbon atoms. 
     
     
         17 . The composition of  claim 1 , wherein the petroleum resin comprises, in polymerized form, an aliphatic diolefin. 
     
     
         18 . The composition of  claim 1 , wherein the petroleum resin comprises, in polymerized form, an aromatic compound comprising an olefinic unsaturated bond and 8 or more carbon atoms.