JP7229231B2 - heat treated oil composition - Google Patents

Description

The present invention relates to heat treated oil compositions.

Metal materials such as steel are subjected to heat treatments such as quenching, tempering, annealing, and normalizing for the purpose of improving their properties. Among these heat treatments, quenching is a process in which a heated metal material is immersed in a coolant to transform into a predetermined quenched structure, and this quenching makes the treated material very hard. For example, if a heated steel material in an austenitic state is immersed in a coolant and cooled at an upper critical velocity or higher, it can be transformed into a quenched structure such as martensite.

As the cooling agent, an oil-based or water-based heat treatment agent is generally used. Explaining the quenching of a metal material using an oil-based heat treatment agent (heat treatment oil), when a heated metal material is put into heat treatment oil as a coolant, it is usually cooled through three stages. Specifically, (1) the first stage (steam film stage) in which the metal material is covered with a steam film of heat-treated oil (2) the second stage (boiling stage) in which the steam film is broken and boiling occurs, (3) In the third stage (convection stage), the temperature of the metal material becomes lower than the boiling point of the heat-treated oil, and heat is taken away by convection. At each stage, the cooling rate is different due to the different atmosphere around the metal material, and the cooling rate is the fastest in the second stage (boiling stage).

Generally, in heat-treated oil, the cooling rate rapidly increases when the vapor film stage is shifted to the boiling stage. If the metal material does not have a simple planar shape, the vapor film stage and the boiling stage tend to coexist on the surface of the metal material. When this mixture occurs, an extremely large temperature difference occurs on the surface of the metal material due to the difference in cooling rate between the vapor film stage and the boiling stage. This temperature difference causes thermal stress and transformation stress, which causes strain in the metal material. Therefore, in the heat treatment of metal materials, especially in quenching, it is important to select a heat treatment oil that is suitable for the heat treatment conditions. Sometimes you can't get it.

Heat-treated oils are classified into types 1 to 3 according to JIS K2242:2012, and those used for quenching are No. 1 oil and No. 2 oil, and No. 1 oil and No. 2 oil are used for quenching.
JIS K2242: 2012 specifies the number of seconds for cooling from 800 ° C to 400 ° C as a guideline for cooling performance, 5.0 seconds or less for Class 1 No. 1, 4.0 seconds or less for Class 1 No. 2, Class 2 1 No. 5.0 seconds or less, Class 2 No. 2 6.0 seconds or less.
The shorter the cooling seconds, the higher the cooling performance and the harder the metal material. In general, there is a trade-off relationship between the hardness and strain of metal after quenching, and the harder the metal, the greater the strain.
Industrially, the 300° C. seconds is also used as an index showing the cooling performance of the oil. The 300° C. seconds is the cooling time from 800° C. to 300° C. of the cooling curve obtained in accordance with the cooling performance test method of JIS K2242:2012.

The number of seconds (characteristic seconds; vapor film length) from the start of the vapor film stage to the temperature at which the vapor film phase ends (characteristic temperature) is also used as an indicator of the cooling properties of the fluid. In general, the longer the vapor film stage, the longer the period during which the vapor film stage and the boiling stage coexist, which tends to increase strain, and the shorter the characteristic seconds and the lower the characteristic temperature, the higher the cooling performance. . JISK 2242:2012 also defines the characteristic temperature, which is 480°C or higher for Type 1 No. 1, 580°C or higher for Type 1 No. 2, 500°C or higher for Type 2 No. 1, and 600°C or higher for Type 2 No. 2. It is defined.
The one type of No. 1 oil and No. 2 oil correspond to cold oil used at low oil temperature, the two types of No. 1 oil correspond to semi-hot oil that can be used at higher oil temperature, and the two types of No. 2 The oil corresponds to hot oil which can be used at high oil temperatures.

The user selects the quenching oil based on the above indicators in order to obtain the desired hardness and distortion. For example, the Class 2 No. 1 oil is widely used for quenching gear parts for automobiles where distortion is a problem. This is because the type 1 oil causes a large strain and the hardness of some parts is too high. In addition, although the above Class 2 No. 2 oil reduces strain, it lacks hardness.

By the way, in most cases, parts such as transmissions and speed reducers for automobiles are mass-produced, and so-called group quenching is performed in which a large amount of processed materials are stacked on one tray and quenched at once. At that time, there is a problem that the cooling performance varies depending on the position where the stacked parts are set, and the hardness and distortion of each part also varies. For example, the hardness of the parts set at the bottom is high, and the hardness of the parts set at the top is low. In view of the above situation, the techniques of Patent Documents 1 to 4 have been proposed.

Patent Literature 1 proposes a heat-treated oil composition that has a cooling performance comparable to that of the Class 2 No. 1 oil while reducing variations in cooling performance during group quenching. Specifically, 5% by mass or more and less than 50% by mass of a low boiling point base oil with a 5% distillation temperature of 300°C or higher and 400°C or lower and 50% by mass of a high boiling point base oil with a 5% distillation temperature of 500°C or higher A heat-treated oil composition comprising a mixed base oil consisting of more than 95% and less.
In Patent Document 2, a base oil having a 40° C. kinematic viscosity of 5 mm ² /s or more and 60 mm ² /s or less is 50% by mass or more and 95% by mass or less based on the total amount of the composition, and a 40° C. kinematic viscosity of 300 mm ² /s or more. A heat-treated oil composition that can reduce variations in cooling performance during group quenching by blending 5% by mass or more and 50% by mass or less of the base oil based on the total amount of the composition and an α-olefin copolymer has been proposed. ing.
In Patent Document 3, as a heat-treated oil composition that has the same cooling performance as the above-mentioned Type 2 No. 1 oil and reduces the variation in cooling performance during group quenching, petroleum resin is included as a vapor film breaking agent, and a characteristic second is 1.00 seconds or less and the 300° C. seconds is 6.00 seconds or more and 14.50 seconds or less.
In Patent Document 4, as a heat-treated oil composition capable of exhibiting high cooling performance, alkenyl or alkylsuccinimide is blended with a base oil having a kinematic viscosity at 40° C. of 4 mm ² /s or more and 20 mm ² /s or less. A heat treating oil composition has been proposed.

Japanese Patent Application Laid-Open No. 2007-009238 JP 2013-194262 A JP 2016-151054 A JP 2010-229479 A

There is a demand for a heat-treating oil composition that has a good balance of cooling performance, quenching hardness, and quenching strain.

The present invention is as follows.
[1] comprising (A) a base oil and (B) a vapor film breaker,
300 ° C. seconds, which is the cooling time from 800 ° C. to 300 ° C. of the cooling curve obtained in accordance with the cooling performance test method of JIS K2242: 2012, is less than 6 seconds,
The heat-treated oil composition, wherein the component (B) contains a petroleum resin.
[2] The heat-treated oil composition according to [1], wherein the characteristic number of seconds obtained from the cooling curve is 1 second or more.
[3] The heat-treated oil composition according to [1] or [2], wherein the characteristic number of seconds obtained from the cooling curve is 2.5 seconds or less.
[4] The heat-treated oil composition according to any one of [1] to [3], wherein the petroleum resin has a softening point of 40 to 150°C.
[5] The heat-treated oil composition according to any one of [1] to [4], wherein the petroleum resin has a number average molecular weight (Mn) of 200 to 5,000.
[6] The petroleum resin contains at least one unsaturated compound selected from aliphatic olefins having 4 to 10 carbon atoms, aliphatic diolefins, or aromatic compounds having 8 or more carbon atoms and having an olefinically unsaturated bond. The heat-treated oil composition according to any one of [1] to [5], wherein the compound is a polymerized or copolymerized resin.
[7] The petroleum resin includes an aliphatic petroleum resin, an aromatic petroleum resin, an aliphatic-aromatic copolymer petroleum resin, a dicyclopentadiene petroleum resin, and a dicyclopentadiene-aromatic copolymer petroleum resin. , and at least one selected from these hydrogenated petroleum resins and modified petroleum resins, the heat-treated oil composition according to any one of [1] to [6].
[8] The heat-treated oil composition according to any one of [1] to [7], which has a kinematic viscosity of 1 to 100 mm ² /s at 40°C.
[9] The component (A) includes a low-viscosity base oil having a kinematic viscosity at 40°C of 1 to 50 mm ² /s and a high-viscosity base oil having a kinematic viscosity at 40°C of more than 50 mm ² /s and not more than 550 mm ² /s. The heat-treated oil composition according to any one of [1] to [8], comprising:
[10] The heat-treated oil composition according to any one of [1] to [9], wherein the number of seconds at 300°C is 4 seconds or more and less than 6 seconds.
[11] The heat-treated oil composition according to any one of [1] to [10], wherein the content of the petroleum resin is 0.1 to 90% by mass based on the total amount of the composition.
[12] The heat-treated oil composition according to any one of [1] to [11], wherein the content of component (A) is 10 to 99.9% by mass based on the total amount of the composition.
[13] The heat-treated oil composition according to any one of [1] to [12], further comprising (C) a gloss improver.
[14] A method for quenching a metal material, which comprises treating the metal material with the heat-treated oil composition according to any one of [1] to [13].
[15] The method for producing a heat-treated oil composition according to any one of [1] to [13], comprising mixing the component (A) and the component (B).

According to the present invention, there is provided a heat-treated oil composition with well-balanced cooling performance, quenching hardness, and quenching strain.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. It should be noted that the present invention is not limited to the following embodiments, and can be arbitrarily modified without departing from the gist of the present invention.

The present invention relates to a heat treated oil composition comprising (A) a base oil and (B) a vapor film breaker. The heat-treated oil composition of the present invention has a cooling curve obtained in accordance with the cooling performance test method of JIS K2242: 2012, and the cooling time from 800 ° C. to 300 ° C. is less than 6 seconds at 300 ° C. Yes, the component (B) contains a petroleum resin.
The heat-treating oil composition of the present invention has an excellent balance of cooling performance, quenching hardness, and quenching distortion.

The heat-treated oil compositions described in Patent Documents 1 to 3 (JP-A-2007-009238, JP-A-2013-194262, JP-A-2016-151054) have a long cooling time and reduced quenching strain. However, there are cases where the quenching hardness is insufficient for application to transportation parts such as automobile parts (for example, gears and bearings), and a further increase in hardness is required. On the other hand, the heat-treated oil composition described in Patent Document 4 (Japanese Patent Application Laid-Open No. 2010-229479) has a short cooling time and high quenching hardness, but has a large quenching strain and is difficult to apply to parts with complicated shapes. . There is still a need for a heat treatment oil composition that can achieve both high quenching hardness and reduced quenching strain.

The heat treatment oil composition of the preferred embodiment can achieve both high quenching hardness and reduced quenching distortion. The heat-treated oil composition of this embodiment can be suitably used for transportation parts such as automobile parts (for example, gears and bearings), particularly large parts.

Each component will be described in detail below. The upper and lower limits of the numerical ranges described herein can be arbitrarily combined. For example, if "AB" and "CD" are recited, the ranges "AD" and "CB" are also included in the scope of the invention. Further, the numerical range "lower limit to upper limit" described in this specification means that the range is equal to or higher than the lower limit and equal to or lower than the upper limit.

[Component (A): base oil]
The base oil is not particularly limited, and can be appropriately selected and used from mineral oils and synthetic oils conventionally used as base oils for heat-treated oils.

Mineral oils include paraffin-based mineral oils, intermediate-based mineral oils and naphthenic-based mineral oils obtained by ordinary refining methods such as solvent refining and hydrorefining, or waxes (gas liquid wax) and those produced by isomerizing mineral oil waxes. These mineral oils may be used alone or in combination of two or more.
Mineral oils are classified as Groups 1, 2 or 3 in the API (American Petroleum Institute) base oil category. Mineral oils are preferably mineral oils classified in groups 2 and 3 of the base oil category, more preferably mineral oils classified in group 3.

Synthetic oils include hydrocarbon-based synthetic oils, ether-based synthetic oils, and the like. Alkylbenzene, alkylnaphthalene, etc. can be mentioned as hydrocarbon system synthetic oil. Examples of ether-based synthetic oils include polyoxyalkylene glycol and polyphenyl ether. These synthetic oils may be used alone or in combination of two or more.
As the base oil, one or more of the mineral oils and one or more of the synthetic oils may be used in combination.

There are no particular restrictions on the viscosity of the base oil. The kinematic viscosity of the base oil at 40° C. is preferably 1 to 50 mm ² /s, more preferably 5 to 40 mm ² /s, even more preferably 7 to 30 mm ² /s, further preferably 10 to 50 mm 2 /s. 25 mm ² /s is particularly preferred. By setting the 40° C. kinematic viscosity of the base oil within the above range, essential cooling performance based on the component (A) can be ensured, and the characteristic seconds and 300° C. seconds can be easily set within the ranges described later.
When the base oil of component (A) is a mixture of two or more base oils, the kinematic viscosity of the mixed base oil preferably satisfies the above range.
As used herein, kinematic viscosity at a given temperature means a value measured according to JIS K2283:2000.

The content of the base oil is preferably 10 to 99.9% by mass, more preferably 50 to 99% by mass, and even more preferably 70 to 98% by mass, based on the total amount of the composition. 85 to 95 mass % is particularly preferred. Appropriate cooling performance and hardness can be obtained within the above range.

In one embodiment of the present invention, the base oil is a low-viscosity base oil having a 40° C. kinematic viscosity of 1 to 50 mm ² /s (more preferably 5 to 35 mm ² /s, still more preferably 9 to 25 mm ² /s). and a high-viscosity base oil having a 40° C. kinematic viscosity of more than 50 mm ² /s and 550 mm ² /s or less (more preferably 55 to 500 mm ² /s, still more preferably 60 to 450 mm ² /s).
The blending of the low-viscosity base oil and the high-viscosity base oil in the mixed base oil is based on the total amount of the composition, and the low-viscosity base oil is 30 to 99.9% by mass (more preferably 35 to 95% by mass). %, more preferably 40 to 90% by mass) and 0 to 70% by mass (more preferably 2 to 60% by mass, still more preferably 5 to 45% by mass) of a high viscosity base oil.

In another embodiment of the present invention, the base oil has a 40° C. kinematic viscosity of 1 to 30 mm ² /s (more preferably 5 to 30 mm ² /s, still more preferably 9 to 25 mm ² /s). It contains a base oil and a high-viscosity base oil having a 40° C. kinematic viscosity of 30 to 500 mm ² /s (more preferably 55 to 500 mm ² /s, still more preferably 60 to 450 mm ² /s).
The blending of the low-viscosity base oil and the high-viscosity base oil in the mixed base oil is based on the total amount of the composition, and the low-viscosity base oil is 30 to 99.9% by mass (more preferably 35 to 95% by mass). %, more preferably 40 to 90% by mass) and 0 to 70% by mass (more preferably 2 to 60% by mass, still more preferably 5 to 45% by mass) of a high viscosity base oil.

[Component (B): Vapor film breaking agent]
The heat treated oil composition contains a petroleum resin as a vapor film breaker. By using petroleum resin, the vapor film stage can be shortened, and the mixture of the vapor film stage and the boiling stage on the surface of the metal material can be made difficult. As a result, variation in cooling performance (variation in hardness and distortion) for each component can be made less likely to occur during quenching. In addition, even if the component has a complicated shape, it is possible to suppress the distortion of each component because it is possible to suppress variations in the cooling performance depending on the location of the component. Furthermore, by containing petroleum resin, the characteristic number of seconds in the initial stage of heat treatment can be shortened, thereby providing excellent cooling performance from the initial stage of heat treatment. In addition, by using a petroleum resin, it is possible to suppress temporal changes in the cooling performance of the heat-treated oil composition when the metal material is repeatedly heat-treated. Therefore, by using a petroleum resin, the life of the heat-treated oil composition can be extended. The reason why the petroleum resin can exhibit these effects is considered to be the thermoplasticity of the petroleum resin and its excellent solubility in the base oil.

Petroleum resins are aliphatic olefins or aliphatic diolefins having 4 to 10 carbon atoms obtained as by-products in the production of olefins such as ethylene by thermal decomposition of petroleum such as naphtha, or carbon numbers having olefinically unsaturated bonds. It is a resin obtained by polymerizing or copolymerizing one or more unsaturated compounds selected from eight or more aromatic compounds. For example, the petroleum resin is a resin (dicyclopentadiene-aromatic copolymer petroleum resin) obtained by copolymerizing unsaturated compounds containing dicyclopentadiene and aromatic compounds, the main raw material of which is C5 fraction.
These petroleum resins include, for example, "aliphatic petroleum resins" obtained by polymerizing aliphatic olefins and/or aliphatic diolefins, and "aromatic petroleum resins" obtained by polymerizing aromatic compounds having olefinically unsaturated bonds. and "aliphatic-aromatic copolymer petroleum resins" obtained by copolymerizing aliphatic olefins and/or aliphatic diolefins with aromatic compounds having olefinically unsaturated bonds.
Examples of aliphatic olefins having 4 to 10 carbon atoms include butene, pentene, hexene and heptene. Examples of aliphatic diolefins having 4 to 10 carbon atoms include butadiene, pentadiene, isoprene, cyclopentadiene, dicyclopentadiene and methylpentadiene. Examples of aromatic compounds having 8 or more carbon atoms and having an olefinically unsaturated bond include styrene, α-methylstyrene, β-methylstyrene, vinyltoluene, vinylxylene, indene, methylindene and ethylindene.
Further, the raw material compounds for the petroleum resin need not all be by-products of the production of olefins by thermal decomposition of petroleum such as naphtha, and chemically synthesized unsaturated compounds may be used. For example, "dicyclopentadiene petroleum resin" obtained by polymerization of cyclopentadiene or dicyclopentadiene (DCPD), or obtained by copolymerizing these cyclopentadiene or dicyclopentadiene with an aromatic compound having an olefinically unsaturated bond. "Dicyclopentadiene-aromatic copolymer petroleum resin" (eg, dicyclopentadiene-styrene petroleum resin) can be used.

As used herein, petroleum resins include derivatives of petroleum resins such as hydrogenated petroleum resins and modified petroleum resins.
A hydrogenated petroleum resin is a hydrogenated petroleum resin obtained by adding hydrogen atoms to the above petroleum resin. Hydrogenation hydrogenates all or part of the double bonds in the molecule. Therefore, the hydrogenated petroleum resin may be a fully hydrogenated petroleum resin or a partially hydrogenated petroleum resin. Partially hydrogenated products are easy to produce because they are excellent in cooling properties and have a low softening point.
Examples of modified petroleum resins include acid-modified petroleum resins obtained by modifying the above-mentioned petroleum resins with acidic functional groups such as carboxylic acids, and acid-modified petroleum resins obtained by modifying the above-mentioned petroleum resins with compounds such as alcohols, amines, alkali metals and alkaline earth metals. Reaction modified resins are included. Acid-modified petroleum resins include carboxylic acid-modified petroleum resins obtained by modifying petroleum resins with unsaturated carboxylic acids or unsaturated carboxylic acid anhydrides, and acid anhydride-modified petroleum resins. Examples of unsaturated carboxylic acids include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid; unsaturated polycarboxylic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid; monomethyl maleate, monoethyl fumarate and the like. partial esters of unsaturated polycarboxylic acids; and the like, and examples of unsaturated carboxylic acid anhydrides include unsaturated polycarboxylic acid anhydrides such as maleic anhydride and itaconic anhydride.

A synthesized petroleum resin may be used, or a commercially available product may be used.
The petroleum resin may be used alone or in combination of two or more.

In one embodiment, the petroleum resin is an aliphatic petroleum resin, an aromatic petroleum resin, an aliphatic-aromatic copolymer petroleum resin, a dicyclopentadiene petroleum resin, and a dicyclopentadiene-aromatic copolymer petroleum resin. resin, and at least one selected from these hydrogenated petroleum resins and modified petroleum resins.

Among them, as the petroleum resin, an aliphatic-aromatic copolymer petroleum resin and a hydrogenated aliphatic-aromatic copolymer petroleum resin are preferable in that the characteristic seconds can be shortened, and in particular, a hydrogenated aliphatic-aromatic Copolymerized petroleum resins are preferred. For example, the petroleum resin is a dicyclopentadiene-aromatic copolymer hydrogenated petroleum resin.

The number average molecular weight (Mn) of the petroleum resin is preferably 200 to 5,000, more preferably 250 to 2,500, and even more preferably 300 to 1,500 in terms of characteristic seconds. Here, the number average molecular weight (Mn) can be measured by the VPO method.

The softening point of the petroleum resin is preferably 40° C. or higher, more preferably 40° C. or higher and 150° C. or lower, even more preferably 60° C. or higher and 150° C. or lower, and 80° C. or higher and 140° C. or lower. more preferably 85° C. or higher and 130° C. or lower, and particularly preferably 85° C. or higher and 120° C. or lower. As used herein, the "softening point" can be measured by the ring and ball method of JIS K2207:2006. By setting the softening point to 40 ° C or higher, it is possible to make it less likely that variations in cooling performance (variation in hardness and strain) will occur for each part during quenching, and if the part has a complicated shape, cooling performance for each location of the part can be made less likely to occur, and distortion of each component can be suppressed. Furthermore, by setting the softening point to 40 ° C. or higher, it is possible to further suppress the change in cooling performance over time (increase in characteristic seconds and decrease in kinematic viscosity over time) when heat treatment is repeated, and heat treatment. can shorten the characteristic seconds at the initial stage of . In addition, by setting the softening point of the petroleum resin to 150° C. or less, it is possible to reduce the stickiness of the surface of the work piece such as a metal material after the work piece is cooled with the heat-treated oil composition. The softening point of the petroleum resin can be adjusted by adjusting the degree of polymerization of the petroleum resin, the modified component, and the degree of modification.
When two or more materials are used as the petroleum resin, it is preferable that all the materials have softening points within the above range.

From the viewpoint of cooling performance, the petroleum resin preferably has a density of 0.5 to 1.5 g/cm ³ at 20° C. measured according to JIS K 0061:2001, and preferably 0.7 to 1.0 g/cm 3 . It is more preferably 3 g/cm ³ and even more preferably 0.8 to 1.1 g/cm ³ .

The bromine number of the petroleum resin is preferably 20 g/100 g or less, more preferably 10 g/100 g or less, and even more preferably 8 g/100 g or less in terms of cooling performance. In addition, the lower the bromine number, the better. Although the lower limit is not particularly limited, it is usually 1.0 g/100 g or more, 1.5 g/100 g or more, or 1.9 g/100 g or more. Here, the bromine number is measured according to JIS K 2605:1996.

As for the hue of the petroleum resin, the Hazen color number measured according to JIS K 6901:2008 is preferably 50 or less, more preferably 40 or less, and even more preferably 30 or less. Further, the lower the Hazen color number, the better, and although the lower limit is not particularly limited, it is usually 3 or more, 5 or more, or 7 or more.

The petroleum resin content is preferably 0.1 to 90% by mass based on the total amount of the composition. If it is 0.1% by mass or more, the cooling performance can be improved. Petroleum resins generally have a high viscosity, and there is a tendency for the viscosity of the composition to increase as the blending amount increases. If it is 90% by mass or less, it is preferable from the point of proper viscosity. The content of the petroleum resin is more preferably 0.1 to 60% by mass, still more preferably 1 to 35% by mass, even more preferably 2 to 25% by mass, and 4 to 15% by mass from the viewpoint of viscosity and cooling performance. Especially preferred.

The heat treated oil composition may contain vapor film breakers other than petroleum resins. Other vapor film breakers include terpene resins, terpene resin derivatives, rosin, rosin derivatives, and the like. The content of other vapor film breaking agents is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, based on the total amount of the composition. Particularly preferably, the heat treated oil composition does not contain vapor film breakers other than petroleum resins.
The heat treated oil composition of one embodiment does not include an alpha olefin copolymer as a vapor film breaker.
The heat treated oil composition of one embodiment does not contain asphalt as a vapor film breaker.

[Component (C): Brightness improver]
The heat treated oil composition may also contain a shine improver. By including the glossiness improver, the appearance of the treated object can be improved. Examples of the gloss improver include oils and fats, fatty acids, alkenylsuccinimides, substituted hydroxyaromatic carboxylic acid ester derivatives, and the like. These luster improvers may be used singly or in combination of two or more.
The content of the glossiness improver is preferably 0.01 to 5% by mass, more preferably 0.02 to 3% by mass, based on the total amount of the composition.

[Component (D): Metallic detergent/dispersant]
The heat treated oil composition may contain a metallic detergent-dispersant. Cooling performance can be enhanced by including a metallic detergent-dispersant. By including (D) the metal-based detergent-dispersant together with (B) the petroleum resin used as the vapor film breaking agent, excellent cooling performance can be exhibited, and the effect of further improving the hardness during quenching can be obtained.

Examples of (D) metallic detergent-dispersants include organometallic compounds containing metal atoms selected from alkali metal atoms and alkaline earth metal atoms (preferably alkaline earth metal atoms). include metal salicylates, metal phenates and metal sulfonates. The metal atom is preferably a sodium atom, a calcium atom, a magnesium atom, or a barium atom, more preferably a calcium atom or a magnesium atom, and still more preferably a calcium atom. Thus, in one embodiment, (D) the metallic detergent-dispersant comprises at least one of calcium salicylate, calcium phenate and calcium sulfonate. The metallic detergent-dispersant may be used alone or in combination of two or more.

(D) The content of the metallic detergent-dispersant is preferably 0 to 10% by mass, more preferably 0.01 to 8% by mass, and even more preferably 0.05 to 5% by mass, based on the total amount of the composition. The above range is preferable from the viewpoint of dispersibility in the base oil and excellent cooling performance.

[Component (E): other additives]
The heat treated oil composition may further contain other additives such as antioxidants. The content of other additives is preferably 10% by mass or less, more preferably 0.01 to 5% by mass, based on the composition.

(Antioxidant)
As the antioxidant, an arbitrary one can be appropriately selected and used from known antioxidants conventionally used as antioxidants for heat-treated oils. Examples thereof include amine-based antioxidants and phenol-based antioxidants.

Examples of amine-based antioxidants include diphenylamine-based antioxidants such as diphenylamine and alkylated diphenylamine having an alkyl group with 3 to 20 carbon atoms; α-naphthylamine, alkyl-substituted phenyl-α-naphthylamine with 3-20 carbon atoms naphthylamine-based antioxidant; and the like.

Phenolic antioxidants include, for example, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, octadecyl-3-(3,5-di monophenolic antioxidants such as -tert-butyl-4-hydroxyphenyl)propionate; 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6 -tert-butylphenol) and other diphenol-based antioxidants; hindered phenol-based antioxidants;

You may use these antioxidants individually by 1 type or in combination of 2 or more types.
The content of the antioxidant is preferably 0.01 to 10% by mass, more preferably 0.03 to 5% by mass, still more preferably 0.05 to 3% by mass, based on the total amount of the composition.

In one embodiment of the present invention, the total content of (A) base oil and (B) vapor film breaker in the heat-treated oil composition is 80 to 100% by mass based on the total amount (100% by mass) of the composition. preferably 90 to 99.75% by mass, particularly preferably 95 to 99.5% by mass.
In one embodiment of the present invention, the total content of (A) base oil, (B) vapor film breaker, (C) brightness improver, and (D) metallic detergent/dispersant in the heat-treated oil composition is , Based on the total amount of the composition (100% by mass), it is preferably 90 to 100% by mass, more preferably 95 to 100% by mass, and particularly preferably 97.5 to 100% by mass.

[Physical properties of heat-treated oil composition]
In the heat-treated oil composition of the present embodiment, the cooling time from 800 ° C. to 300 ° C. in the cooling curve obtained in accordance with the cooling performance test method of JIS K2242: 2012, "300 ° C. seconds" is 6. Must be less than seconds. If the 300° C. seconds is 6 seconds or longer, the hardness tends to be insufficient. From the viewpoint of hardness, the 300° C. seconds is more preferably 4 seconds or more and less than 6 seconds, still more preferably 4.5 seconds or more and less than 6 seconds, and particularly preferably 5 seconds or more and less than 6 seconds.
In order to make the 300 ° C. seconds of the heat-treated oil composition within the above range, (A) the content and kinematic viscosity of the base oil, (B) the content, softening point and number of the vapor film breaking agent (especially petroleum resin) It is preferable that the content, structure, etc. of the average molecular weight (D) metal-based detergent-dispersant be within the range of the above-described embodiment.

A heat-treated oil composition having a 300° C. second in the above range can be used as a heat-treated oil (cold oil) having cooling performance equivalent to that of Class 1 No. 1 oil or No. 2 oil in JIS K2242: 2012, for example. can. The heat-treated oil composition of one embodiment can reduce quenching strain compared to conventional cold oil, and can achieve both reduced quenching strain and high quenching hardness.

In terms of cooling performance, the heat-treated oil composition of one embodiment has a cooling time from 800 ° C. to 400 ° C. of the cooling curve obtained in accordance with the cooling performance test method of JIS K2242: 2012 "400 ℃ Seconds" is preferably 1.0 to 5.0 seconds, more preferably 1.5 to 4.0 seconds, even more preferably 2.0 to 3.5 seconds.

In terms of strain reduction, the heat-treated oil composition of the present embodiment has a characteristic number of seconds (steam film length) obtained from a cooling curve obtained in accordance with the cooling performance test method of JIS K2242: 2012, which is 1 second or more. is preferably , more preferably 1.2 seconds or longer, and even more preferably 1.4 seconds or longer. In addition, from the viewpoint of reducing variations in cooling performance for each component during quenching, the time is preferably 2.5 seconds or less, more preferably 2.0 seconds or less, and even more preferably 1.5 seconds or less.
For example, the characteristic number of seconds (vapor film length) obtained from the cooling curve is 1 second or more and 2.5 seconds or less, 1 second or more and 2.0 seconds or less, 1 second or more and 1.5 seconds or less, 1.2 seconds or more. 2.5 seconds or less, 1.2 seconds or more and 2.0 seconds or less, 1.2 seconds or more and 1.5 seconds or less, 1.4 seconds or more and 2.5 seconds or less, 1.4 seconds or more and 2.0 seconds or less, Alternatively, it is 1.4 seconds or more and 1.5 seconds or less.
In order to make the characteristic seconds of the heat-treated oil composition within the above range, (A) the content and kinematic viscosity of the base oil, (B) the content, softening point and number average of the vapor film breaking agent (especially petroleum resin) It is preferable that the content, structure, etc. of the molecular weight (D) metal-based detergent-dispersant be within the range of the above-described embodiment.

More specifically, the characteristic number of seconds can be calculated by the following (1) and (2).
(1) In accordance with the cooling performance test method of JIS K2242: 2012, a silver sample heated to 810 ° C. is put into a heat-treated oil composition, and cooling is performed with time on the x axis and the temperature of the silver sample surface on the y axis. find the curve.
(2) From the cooling curve, the number of seconds until reaching the temperature (characteristic temperature) at which the vapor film stage of the heat-treated oil composition ends is calculated by the tangent intersection method, and the number of seconds is defined as the number of characteristic seconds.
In (1) above, it is preferable to set the measurement time interval to 1/100 second.

The kinematic viscosity at 40° C. of the heat-treated oil composition is preferably 1 to 100 mm ² /s from the viewpoint of 300° C. seconds.
The kinematic viscosity at 100° C. of the heat-treated oil composition is preferably 20 mm ² /s or less.

[Method for producing heat-treated oil composition]
The method for producing the heat-treated oil composition of the embodiment is not particularly limited. For example, the manufacturing method of the embodiment includes (A) a base oil and (B) a vapor film breaker, and optionally (C) a glitter improver, (D) a metallic detergent and dispersant and (E) other Including mixing the ingredients. Components (A) to (E) may be blended in any manner, and the order and method of blending are not limited.

[Usage of heat-treated oil composition, quenching method]
Since the heat treatment oil composition of the embodiment can exhibit excellent cooling performance in heat treatment of metal materials, for example, various alloy steels such as carbon steel, nickel-manganese steel, chromium-molybdenum steel, and manganese steel are quenched. It can be suitably used as a heat-treated oil at the time. In particular, the heat-treated oil composition of the embodiment can achieve improved quenching hardness while suppressing quenching strain. can be preferably used as.
The temperature range of the heat-treated oil composition when the metal material is quenched using the heat-treated oil composition of the embodiment may be set in the range of 60 to 150 ° C., which is the temperature of normal quenching treatment. , 170-250°C.
One embodiment of the present invention provides a method of heat treating a metallic material. Specifically, the heat treatment method includes heat-treating a metal material using the heat-treated oil composition of the above embodiment.
One embodiment of the present invention provides a method of hardening a metallic material. Specifically, the heat treatment oil composition of the above embodiment is used to treat a metal material. In a preferred embodiment, the method for quenching a metal material is characterized by treating the metal material using the heat-treating oil composition of the above embodiment in group quenching of the metal material. One embodiment of the present invention provides a method of group quenching a metal material, comprising treating the metal material with the heat treatment oil composition of the above embodiment.
In one embodiment, a method of quenching a metallic material includes treating the metallic material under an oil temperature of 40-200°C.
For example, if a heated steel material in an austenitic state is immersed in a coolant and cooled at an upper critical velocity or higher, it can be transformed into a quenched structure such as martensite.

The present invention will be described in detail below with reference to examples, but the technical scope of the present invention is not limited to these.
The raw materials used in Examples and Comparative Examples and the physical properties of the heat-treated oil compositions of Examples and Comparative Examples were measured according to the following procedures.

(1) Kinematic Viscosity According to JIS K2283:2000, kinematic viscosity at 40° C. and kinematic viscosity at 100° C. were measured using a glass capillary viscometer.
(2) Cooling performance of heat-treated oil composition In accordance with the cooling performance test method specified in JIS K2242: 2012, a silver sample heated to 810 ° C. is put into the heat-treated oil composition, and the cooling curve of the silver sample is obtained. , the following "characteristic seconds" and "300°C seconds" were calculated. The oil temperature of the heat-treated oil composition before adding the silver sample was 80° C. in all examples and all comparative examples.
<Characteristic seconds and characteristic temperature>
In the above cooling curve, the temperature at which the vapor film stage ends (characteristic temperature) was calculated according to JIS K2242:2012, and the number of seconds until reaching that temperature was defined as the characteristic number of seconds.
<Number of seconds at 300°C>
The cooling time from 800° C. to 300° C. in the cooling curve was defined as 300° C. seconds.
<Number of seconds at 400°C>
The cooling time from 800° C. to 400° C. in the cooling curve was defined as 400° C. seconds.
(3) Physical properties of petroleum resin (i) Softening point Measured according to JIS K2207:2006.
(ii) number average molecular weight (Mn)
It was measured by the VPO method.
(iii) Density The density at 20°C was measured according to JIS K 0061:2001.
(iv) Hue Hazen color number was measured according to JIS K 6901:2008.
(v) Bromine number Measured according to JIS K 2605:1996.

[Examples 1 to 3, Comparative Examples 1 to 5]
As shown in Table 1 below, each component shown in Table 1 below was blended with the base oil to prepare the heat-treated oil compositions of Examples and Comparative Examples containing the base oil and these components, and the prepared heat-treated The following hardness and strain evaluations were performed on the oil composition. The properties and evaluation results of the heat-treated oil compositions of Examples and Comparative Examples are shown in Table 1 below.

<Evaluation of hardness and strain>
As a material for quenching evaluation, a cylindrical case-hardened steel (outer diameter: φ85 mm, height: 44 mm, wall thickness: 4 mm, material: chromium-molybdenum steel SCM415) is used, and heat treatment (group quenching) is performed under the following conditions. Furthermore, the following items were evaluated. The smaller the average ellipticity, the smaller the quenching strain, and the larger the average internal hardness, the higher the quenching hardness. The larger the average effective case depth and the average internal hardness, the higher the hardness of the treated product after quenching, indicating that the heat treatment oil has excellent cooling performance.
<Conditions such as heat treatment>
Heat treatment conditions: Carburizing process 930°C x 150 minutes, carbon potential (CP) = 1.1% by mass
Diffusion process: 930°C x 60 minutes, CP = 0.8 mass%
Soaking process: 850 ° C. x 20 minutes, CP = 0.8 mass%
Oil cooling conditions: oil temperature 80°C, oil cooling time 10 minutes, agitation 20 Hz
Tempering conditions: 180°C x 60 minutes Setting method: Sword rack (8 hardened workpieces, 4 x 2 stages)
<Evaluation items>
・Average ellipticity (mm)
・Average internal hardness (hardened material 1.5 mm inside, HV)
・Average effective hardened layer depth (mm)

The ingredients used in Table 1 are as follows.
1. Base oil (component (A))
Base oil 1: paraffinic mineral oil (40° C. kinematic viscosity 14 mm ² /s) (low viscosity base oil)
Base oil 2: Paraffinic mineral oil (40° C. kinematic viscosity 75 mm ² /s) (high viscosity base oil)
Base oil 3: Mineral oil (40°C kinematic viscosity 9.8 mm ² /s) (low viscosity base oil) classified in Group 3 of the API base oil category
Base oil 4: Paraffinic mineral oil (40° C. kinematic viscosity 9.8 mm ² /s) (low viscosity base oil)
Base oil 5: paraffinic mineral oil (40° C. kinematic viscosity 20 mm ² /s) (low viscosity base oil)
Base oil 6: Paraffinic mineral oil (40° C. kinematic viscosity 120 mm ² /s) (high viscosity base oil)
Base oil 7: Paraffinic mineral oil (40° C. kinematic viscosity 60 mm ² /s) (high viscosity base oil)
Base oil 8: Paraffinic mineral oil (40° C. kinematic viscosity 200 mm ² /s) (high viscosity base oil)
Base oil 9: Paraffinic mineral oil (40° C. kinematic viscosity 424 mm ² /s) (high viscosity base oil)
2. Vapor film breaking agent (component (B))
Petroleum resin 1: Partially hydrogenated aliphatic-aromatic copolymer petroleum resin (hydrogenated petroleum resin of dicyclopentadiene/aromatic copolymer based on C5 fraction; softening point 110 ° C., number average molecular weight 760, density at 20° C.: 1.05 g/cm ³ , hue (Hazen color number): 25, bromine number: 6 g/100 g)
α-olefin copolymer: α-olefin copolymer having a kinematic viscosity of 2000 mm ² /s at 100° C.3. Additive Antioxidant: Phenolic antioxidant Brightness improver: Fatty acid

As shown in Table 1, (B) the heat-treated oil composition of the example containing a petroleum resin as a vapor film breaker and having a 300° C. second time of less than 6 seconds has an average internal hardness of 430 Hv or more. , and that the value of the average ellipticity is small.
On the other hand, when the number of seconds at 300° C. was 6 seconds or more and/or no petroleum resin was contained, at least one or both of desired hardness and low strain (average ellipticity) could not be obtained.

The scope of the present invention is not limited to the above description, and other than the above examples can be appropriately changed and implemented without impairing the gist of the present invention. All documents and publications mentioned herein are hereby incorporated by reference in their entirety regardless of their purpose. In addition, this specification includes the claims and the disclosure of the specification of Japanese Patent Application No. 2018-062470 (filed on March 28, 2018), which is the basis for claiming priority of this application. do.

The heat treatment oil composition of the present invention can be suitably used for heat treatment such as quenching of metal materials.

Claims (14)

(A) a base oil and (B) a vapor film breaker,
300 ° C. seconds, which is the cooling time from 800 ° C. to 300 ° C. of the cooling curve obtained in accordance with the cooling performance test method of JIS K2242: 2012, is less than 6 seconds,
The component (B) contains a petroleum resin,
The component (A) is a low-viscosity base oil having a 40° C. kinematic viscosity of 1 to 50 mm ² /s and a 40° C. kinematic viscosity of 1 to 50 mm ² /s, and a 40° C. kinematic viscosity of 50 mm ² /s. containing a high viscosity base oil that is greater than 550 mm ² /s or less,
The content of the component (A) is 70 to 98% by mass based on the total amount of the composition,
The heat-treated oil composition, wherein the content of the petroleum resin is 2 to 25% by mass based on the total amount of the composition . 2. The heat-treated oil composition according to claim 1, wherein the characteristic number of seconds obtained from the cooling curve is 1 second or more. 3. The heat-treated oil composition according to claim 1, wherein the characteristic number of seconds obtained from the cooling curve is 2.5 seconds or less. The heat-treated oil composition according to any one of claims 1 to 3, wherein the petroleum resin has a softening point of 40 to 150°C. The heat-treated oil composition according to any one of claims 1 to 4, wherein the petroleum resin has a number average molecular weight (Mn) of 200 to 5,000. In the petroleum resin, at least one unsaturated compound selected from aliphatic olefins having 4 to 10 carbon atoms, aliphatic diolefins, or aromatic compounds having 8 or more carbon atoms having an olefinically unsaturated bond is polymerized. or a copolymerized resin, according to any one of claims 1 to 5. The petroleum resin includes an aliphatic petroleum resin, an aromatic petroleum resin, an aliphatic-aromatic copolymer petroleum resin, a dicyclopentadiene petroleum resin, and a dicyclopentadiene-aromatic copolymer petroleum resin, and these The heat-treated oil composition according to any one of claims 1 to 6, which is at least one selected from hydrogenated petroleum resins and modified petroleum resins. The heat-treated oil composition according to any one of claims 1 to 7, which has a 40°C kinematic viscosity of 1 to 100 mm ² /s. The heat-treated oil composition according to any one of claims 1 to 8 , wherein the number of seconds at 300°C is 4 seconds or more and less than 6 seconds. The content of the component (A) is 85 to 95% by mass based on the total amount of the composition, and the content of the petroleum resin is 4 to 15% by mass based on the total amount of the composition. 10. The heat-treated oil composition according to any one of 9. The heat-treated oil composition according to any one of claims 1 to 10 , further comprising (C) a gloss improver. The heat-treated oil composition according to claim 11, wherein the content of component (C) is 0.01 to 5% by mass based on the total amount of the composition. A method for quenching a metal material, which comprises treating the metal material with the heat-treated oil composition according to any one of claims 1 to 12 . A method for producing a heat-treated oil composition according to any one of claims 1 to 12 , comprising mixing said component (A) and said component (B).