EP0113157A1

EP0113157A1 - Quench oils, concentrates for making quench oils and methods of treating metals

Info

Publication number: EP0113157A1
Application number: EP83300321A
Authority: EP
Inventors: Alan Brown; Alan John Mills
Original assignee: Edwin Cooper and Co Ltd
Current assignee: Edwin Cooper and Co Ltd
Priority date: 1982-12-30
Filing date: 1983-01-21
Publication date: 1984-07-11

Abstract

An improved quench oil for use in heat treating ferro-metals comprising a major amount of mineral oil containing (a) an ashless dispersant (e.g. alkenyl succinimide, alkenyl succinic ester, alkenyl succinic ester-amide or alkylphenolformaldehyde-amine Mannich condensate), (b) an alkaline earth or an alkali metal detergent (e.g. calcium aryl sulfonate, calcium phosphonate phenate), and (c) an ashless antioxidant (e.g. alkylated diphenylamine, sterically hindered phenols or sulfurized alkylphenols).

Description

Properties of steel can be varied by heat treatment to obtain desired microstructures such as martensitic microstructure. Quenching and tempering is the heat treatment commonly used to obtain such microstructures. It involve.s heating steel to an austenitizing temperature such as 800°C, and then cooling through the martensite transformation temperature range at a rate rapid enough to minimise transformation at temperatures above the martensite range. This is accomplished by quenching the heated steel. The first requisite of a quenching medium is therefore a sufficient cooling rate to obtain the desired results. The temperature gradient caused by the quenching operation results in relatively high thermal and transformation stresses which may if excessive lead to cracking or distortion. In the prevention of these problems, the maximum quenching rate is limited by the nature of the component being heat treated.
Quenching media commonly used are water, oil and brine. Brine quenching is the most severe. Water approaches it in severity. Oil quenching is much less drastic. It has been proposed to add to various mineral oils to be used as quench oils an ashless dispersant such as an alkenyl succinimide. See for instance United States Patent Specification No. 3866603.
A need remains however for a quench oil having improved chemical stability and less tendancy to deposit material on work pieces quenched therein.
According to the present invention quench oil is provided which comprises a major amount of a mineral oil and contains effective amounts of ashless dispersent, alkaline earth metal or alkali metal detergent, and ashless antioxidant.
A preferred embodiment of the invention is a quench oil for use in the heat treatment of ferro-metals, said composition comprising a major amount of mineral oil and (a) about 0.3 - 7.5 weight percent of ashless dispersant which is one or more of (i) a polyisobutenyl succinimide of an alkylenepolyamine, (ii) a polyisobutenyl succinic ester of an alcohol containing 1-20 carbon atoms and 1-6 hydroxy groups, (iii) a polyisobutenyl succinic ester-amide of a mixture of (x) an amine containing 2-10 carbon atoms and 2-10 amine nitrogen atoms, and (y) an alcohol containing 1-20 carbon atoms and 1-6 hydroxy groups, and optionally 1-4 amine nitrogen atoms, or (iv) a Mannich condensate of a polyisobutylphenol, formaldehyde, and an amine containing 1-20 carbon atoms and 1-10 amine groups at least one of which is a primary amine group; (b) 0.2 - 2.5 weight percent of alkaline earth or alkali metal detergent which is one or more of an alkaline earth metal arylsulfonate, alkali metal arylsulfonate, alkaline earth metal alkylphenate, alkaline earth metal sulfurized alkylphenate or an alkaline earth metal phosphonate phenate and (c) 0.01 - 20 weight percent of ashless antioxidant which is one or more of (i) a sterically hindered phenol, (ii) an alkylated aromatic amine, or (iii) a sulfurized alkylphenol.
The base mineral oil is suitably a liquid hydrocarbon obtained by conventional petroleum refining methods including hydrocracking, hydrotreating and the like. A useful viscosity range is about 1.5 to 20cSt at 1000C and more preferably 4 to l2cSt at 100°C.

The Ashless Dispersant

The preferred ashless dispersant is an alkenyl succinimide of an amine having at least one primary amine group capable of forming an imide group. Representative examples are given in US 3,172,892; US 3,202,678; US 3,219,666; US 3,272,746; US 3,254,025 and US 3,216,936. The alkenyl succinimides may be formed by conventional methods such as by heating an alkenyl succinic anhydride, acid, acid-ester or lower alkyl ester with an amine containing at least one primary amine group. The alkenyl succinic anhydride may be made readily by heating a mixture of olefin and maleic anhydride to about 180°-220°C. The olefin is preferably a polymer or copolymer of a lower monoolefin such as ethylene, propylene, isobutylene and the like. The more preferred source of alkenyl group is from polyisobutylene having a molecular weight up to 10,₀00 or higher. In a still more preferred embodiment the alkenyl is a polyisobutylene group having a molecular weight of about 700-5,000 and most preferably about 900-2,000.
Amines which may be employed include any that have at least one primary amine group which can react to form an imide group. A few representative examples are:

methylamine
2-ethylhexylamine
n-dodecylamine
stearylamine
N,N-dimethyl-propanediamine N-(3-aminopropyl)morpholine
N-dodecyl propanediamine
N-aminopropyl piperazine ethanolamine N-ethanol ethylene diamine

The preferred amines are the alkylene polyamines such as propylene diamine, dipropylene triamine, di-(l,2-butylene)-triamine, tetra-(l,2-propylene)pentaamine.
The most preferred amines are the ethylene polyamines which have the structure H₂N-(CH₂CH₂NH)_n-H wherein n is an integer from one to about ten. These include:

ethylene diamine
diethylene triamine
triethylene tetraamine
tetraethylene pentaamine
pentaethylene hexaamine and the like including mixtures thereof in which case n is the average value of the mixture. These ethylene polyamines have a primary amine group at each end so can form mono-alkenylsuccinimides and bis-alkenylsuccinimides. The most preferred for use in this invention are the bis-alkenylsuccinimides.

Another class of useful ashless dispersants includes alkenyl succinic acid esters and diesters of alcohols containing 1-20-carbon atoms and 1-6 hydroxyl groups. Representative examples are described in US 3,331,776; US 3,381,022 and US 3,522,179. The alkenyl succinic portion of these esters corresponds to the alkenyl succinic portion of the succinimides described above including the same preferred and most preferred sub-genus e.g. polyisobutenyl succinic acids wherein the polyisobutenyl group has an average molecular weight of 900-2,000.
Alcohols useful in preparing the esters include methanol, ethanol, isobutanol, octadecanol, eicosanol, ethylene glycol, diethylene glycol, tetraethylene glycol, diethylene glycol monethylether, propylene glycol, tripropylene glycol, glycerol, sorbitol, 1,1,1-trimethylol ethane, 1,1,1,-trimethylol propane, 1,1,1-trimethylol butane, pentaerythritol, dipentaerythritol,-and the like.
The succinic esters are readily made by merely heating a mixture of alkenyl succinic acid, anhydrides or lower alkyl (e.g.C₁-C₄) ester with the alcohol while distilling out water or lower alkanol.
In the case of acid-esters less alcohol is used. In fact, acid-esters made from alkenyl succinic anhydrides do not evolve water. In another method the alkenyl succinic acid or anhydride can be merely reacted with an appropriate alkenyl oxide such as ethylene oxide,.propylene oxide, and the like, including mixtures thereof.
In another embodiment the ashless dispersant is an alkenyl succinic ester-amide mixture. These may be made by heating the above-described alkenyl succinic acids, anhydrides or lower alkyl esters with an alcohol and an amine either sequentially or in a mixture. The alcohols and amines described above are also useful in this embodiment. Alternatively, amino alcohols can be used alone or with the alcohol and/or amine to form the ester-amide mixtures. The amino alcohol can contain 1-20 carbon atoms, 1-6 hydroxy groups and 1-4 amine nitrogen atoms. Examples are ethanolamine, diethanolamine, N-ethanol-diethylene triamine, trimethylol aminomethane.
Representative examples of suitable ester-amide mixtures are described in US 3,184,474; US 3,576,743; US 3,632,511; US 3,804,763; US 3,836,471; US 3,862,981; US 3,936,480; US 3,948,800; US 3,950,341; US 3,957,854; US 3,957,855; US 3,991,098; US 4,071,548 and US 4,173,540.
Another useful class of ashless dispersants includes the Mannich condensates of hydrocarbyl-substituted phenols, formaldehyde or formaldehyde precursors (e.g. paraformaldehyde) and an amine having at least one primary amine group and containing 1-10 amine groups and 1-20 carbon atoms. Mannich condensates useful in this invention are described in US 3,442,808; US 3,448,047; US 3,539,633; US 3,591,598; US 3,600,372; US 3,634,515; US 3,697,574; US 3,703,536; US 3,704,308; US 3,725,480; US 3,726,882; US 3,736,357; US 3,751,365; US 3,756,953; US 3,793,202; US 3,798,165; US 3,798,247; US 3,803,039, and US '3,413,347.
More preferred Mannich condensates are those made by condensing a polyisobutylphenol wherein the polyiso- butyl group has an average molecular weight of about 800-3,000 with formaldehyde or a formaldehyde precursor and an ethylene polyamine having the formula H₂N-(CH₂CH₂NH)_nH wherein n is an integer from one to ten or mixtures thereof especially those in which n has an average value of 3-5.
The amount of ashless dispersant in the quench oil can vary over a wide range. A useful concentration range is about 0.3 - 7.5 weight percent. A more preferred concentration is about 0.7 - 4 weight percent.

The Alkaline Earth or Alkali Metal Detergent

The more preferred alkaline earth or alkali metal detergents are the alkaline earth or alkali metal arylsulfonates. These include both the so-called natural sulfonates derived by sulfuric extraction of petroleum as well as the synthetic sulfonates made by sulfonating synthetic alkylbenzenes. The alkaline earth metal sulfonates include both neutral and over based sulfonates. The term "alkaline earth metal" as used herein includes calcium, barium and magnesium. The term "alkali metal" as used herein includes sodium.
The most preferred alkaline earth metal arylsulfonates are the calcium salts of alkylbenzene sulfonic acids in which the alkylbenzenes have an average molecular weight of about 300-700.
Another useful class of alkaline earth metal detergents includes the alkaline earth metal alkyl phenates (e.g. US 2,228,671; US 2,252,663; US 2,280,419; US 2,412,903; US 2,610,982; US 3,779,920; US 3,691,076) and alkaline earth metal sulfurized alkyl phenates. (e.g. US 2,249,626; US 2,331,448; US 2,336,074; US 2,342,887; US 2,346,826; US 2,362,292; US 2,366,874; US 2,406,564). These are made by reacting alkaline earth metal hydroxide or oxide (e.g. CaO, Ca(OH)₂, BaO, Ba(OH)₂, MgO, Mg(OH)₂) with an alkylphenol or sulfurized alkylphenol.
The alkyl substituent preferably contains about 4-20 carbon atoms such as in isobutylphenol, 2-ethylhexylphenol, nonylphenol, 1-ethyldecylphenol and the like. The corresponding sulfurized detergent is made by well-known methods such as by heating a mixture of alkylphenol and sulfur and then reacting the sulfurized phenols with an alkaline earth metal base.
Alkaline earth metal phosphonate phenates are typically made by the coneutralisation of a mixture of a phosphosulphurized polyolefin and an alkyl phenol or an alkyl phenol sulfide. Coneutralisation may be carried using, for example barium oxide, barium hydroxide, calcium oxide or calcium hydroxide or an alkoxide of magnesium or a carbonated alkoxide of magnesium in an alkanol, such as described in British Patent 1303048.
The alkylphenol sulphide (that is to say a compound containing two or more alkylphenol residues linked by one or more sulphur atoms) or the alkylphenol is preferably one which has--an aromatic nucleus that is substituted by-an alkyl group having from 5 to 20 carbon atoms, especially from 7 to 12 carbon atoms. An alkyl group having 9 carbon atoms is often particularly satisfactory.
It is often preferable to use an alkylphenol sulphide rather than the alkylphenol itself. The sulphide can be a monosulphide, but disulphides, trisulphides, tetra- sulphides, pentasulphides and other polysulphides are also very useful. A suitable alkylphenol sulphide can in fact be made from an appropriate alkylphenol by reaction with sulphur dichloride, the composition of the product depending on the molar ratio of alkylphenol to sulphur dichloride used and the alkylphenol residues being linked in general by monosulphide links.
Examples of suitable alkylphenol sulphide and alkylphenol starting materials are nonylphenol and dodecylphenol and the product of reacting from three to five moles of an alkylphenol in which the alkyl group has from 7 to 11 carbon atoms with from two to four moles of sulphur dichloride. A particularly preferred example being the reaction product of four moles of nonylphenol and three moles of sulphur dichloride.
The polyolefin that is used in phosphosulphurised form is preferably one of relatively low molecular weight; it can be for example a polypropylene,-polybutene or polyisobutylene, for instance one that has an average molecular weight between 500 and 2500, for example 1100. It can for instance have been phosphosulphurised by reacting it with a phosphorus sulphide such as for example P₄S₃, P₄S₇, or more preferably P₂S₅. The phosphosulphurised polyolefin can be used as such that is to say in the form in which it is produced by phosphosulphurisation.
The alkylphenol sulphide or alkylphenol and the phosphosulphurised polyolefin can be used in any desired relative proportion, but usually it is preferred to employ these in a weight ratio between 1: 12 and 6: 1 especially between 1: 9 and 4: 1 and more preferably between 3: 7 and 1: 1.
The amount of alkaline earth metal detergent can vary from about 0.02 to about 2.5 weight percent. A preferred range is about 0.05 to 2.0 weight percent and a most preferred range is about 0.1 to 1.0 weight percent.

The Ashless Antioxidant

A very useful class of ashless antioxidants includes the hindered phenols. These are phenolic compounds having at least one tert-alkyl group substituted at a nuclear position ortho to a phenolic hydroxyl group. Representative examples of these are:

2,6-di-tert-butyl-4-methylphenol
2,6-di-tert-butyl-4-ethylphenol
2,6-di-tert-butylphenol
4,4'-methylenebis(2,6-di-tert-butylphenol) 4,4'-bis(2,6-di-tert-butylphenol)
2,6-di-tert-butyl-α-(dimethylamino)p-cresol 2,2'-methylenebis(4-methyl-6-tert-butylphenol) 2,2'-ethylidenebis (4,6-di-tert-butylphenol) 1,3,5-tri(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene
octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate
tetra-[-(3,5-di-tert-butyl-4-hydroxyphenyl)propionat]-pentaerythritol
0,0-di-octadecyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate and the like.

Another useful class of ashless antioxidants are the aromatic amines. Examples of these are N_',N'-di-octyl phenylenediamine, N-isopropylphenylenediamine and the like.
The most preferred of these are the alkylated diphenylamines such as di- (octylphenyl)amine di-(dodecylphenyl)amine octylphenyl dodecylphenylamine and the like. Of the sub-class the most preferred is di-(nonylphenyl)amine.
Sulfurized alkylphenols can also be used as the ashless antioxidant. These can be made by reacting an alkylphenol with elemental sulfur at elevated temperature. This forms sulfur bridging groups between alkylphenol molecules. The phenols are preferably para-alkylated. Examples of alkylphenols which make useful sulfurized products are:

p-dodecylphenol
p-octadecylphenol
p-eicosylphenol
p-isobutylphenol
and the like. The most preferred is sulfurized p-nonylphenol.

The amount of ashless antioxidant in the quench oil should be an amount that provides the required amount of stablization. A useful range is about 0.01 to 2 weight percent and more preferably about 0.05 to 1.0 weight percent.
In commerce a convenient way to prepare the quench oil is to add a quench oil concentrate to the mineral oil base. The concentrate contains the proper amount of each additive such that when blended in the mineral oil base the resultant quench oil will contain the proper amount of each additive. In the concentrate a useful concentration range of each class of additive is 25 to 60 weight percent ashless dispersant, 2 to 15 weight percent alkaline earth metal detergent, and 1 to 20 weight percent ashless antioxidant.
The invention will be illustrated by the following examples.

Examples

Initially tests were conducted to compare the cooling rate of the present quench oil according to the invention with the cooling rate of the base oil. The method used was the Wolfson Heat Treatment Centre Test Method. In this test a specified stainless steel probe of length 60mm and diameter 12.5mm and containing a thermocouple is soaked at 850°C in a furnace and then rapidly transferred to a 2 litre sample of the quench oil held at 40°C. The temperature vs time and the rate of temperature change vs temperature as measured by the thermocouple are recorded.
The test method is described in detail in "Laboratory Test for Assessing the Cooling Characteristics of Industrial Quenching Media" ISBN O 9507768 2 3 available from the Wolfson Heat Treatment Centre, The University of Aston in Birmingham, Gosta Green, Birmingham B4 7ET England.
First a quench oil concentrate "A" according to the invention was prepared containing

36 wt % mineral oil
48 wt % polyisobutenylsuccinimide
6 wt % Ca phosphonate phenate

10 wt % Di-(nonylphenyl)amine

1. Bis-polyisobutenylsuccinimide of ethylenepolyamine mixture having average composition of tetraethylenepentamine and having a nitrogen content of 2.7%.
2. Calcium phosphonate phenate having a calcium content of 3.3%, a phosphorus content of 2.2%, a sulfur content of 6.0% and a total base number (IP method 276) of 92.

The test results were as follows:
. These test results show that the present additive package provides a significant increase in quenching rate.
Further tests were conducted to measure the thermal stability of the quench oil. In the Panel Coker test the oil sample was splashed against a heated (315⁰C) aluminum plate intermittently (45 sec splash - 15 sec no splash) while air was circulated through the test cell.at the rate of 2.3 litre per hour. The test duration was 14.75 hours. Test criteria was the amount of deposit formed on the heated aluminum plate. The results were as follows:
These results show that not only is the quenching rate improved but also the deposition tendency is much reduced.
An Oxidative Stability Test was conducted by bubbling air through a test oil at 150°C for 72 hours at 10 1/hr. A small amount of iron acetylacetonate (40ppm) was added to the test oil to promote oxidation. Test criteria were the increase in total acid number (TAN), percent insolubles and percent viscosity increase measured at 40°C. Results were as follows:
These results attest to the excellent oxidative stability of the quench oil containing the present additive combination.
A series of quench oils was formulated as follows:
The quench oils in Table IV were subjected to the Panel Coker Test and also tested by the Wolfson Test Method for quench characteristics.
The above results show that the present compositions 20 are effective quench oils with low depositiom tendency and good oxidative stability. Quench oil "m" is unique in that it is stable without the di-nonylphenyl amine. Thus a further embodiment of the invention is a quench oil comprising a major amount of mineral oil and about 0.3 - 7.5 weight percent of a polyisobutenyl (m.w. 700-5000) succinimide of an ethylenepolyamine and 0.05 - 2.5 weight percent of a sulfurized alkylphenol.
The improved oils described above provide a cooling rate which is fast enough to achieve the required degree of hardness, without inducing excessive stress. They also do not stain the piece and are exceptionally stable allowing use over an extended period without undesirable changes in oil condition and quenching characteristics.

Claims

1. A quench oil which comprises a major proportion of a mineral oil and an effective amount of (a) ashless dispersant, characterised in that the composition contains an effective amount of (b) alkaline earth metal or alkali metal detergent and (c) ashless antioxidant.

2. A quench oil for use in the heat treatment of ferro-metals, said composition comprising a major amount of mineral oil and (a) about 0.3 - 7.5 weight percent of ashless dispersant which is one or more of (i) a polyisobutenyl succinimide of an alkylenepolyamine, (ii) a polyisobutenyl succinic ester of an alcohol containing 1-20 carbon atoms and 1-6 hydroxy groups, (iii) a polyisobutenyl succinic ester-amides of a mixture of (x) an amine containing 2-10 carbon atoms and 2-10 amine nitrogen atoms and (y) an alcohol containing 1-20 carbon atoms and 1-6 hydroxy groups and optionally 1-4 amine nitrogen atoms, or (iv) a Mannich condensate of a polyisobutylphenol, formaldehyde, and an amine containing 1-20 carbon atoms and 1-10 amine groups at least one of which is a primary amine group; (b) 0.2 - 2.5 weight percent of alkaline earth or alkali metal detergent which is one or more of alkaline earth metal arylsulfonate, alkali metal arylsulfonate, alkaline earth metal alkylphenate, alkaline earth metal sulfurized alkylphenate or an alkaline earth metal phosphonate phenate and (c) 0.01 - 2.0 weight percent of ashless antioxidant which is one or more of (i) a sterically hindered phenol, (ii) an alkylated aromatic amine, or (iii) a sulfurized alkylphenol.

3.. A quench oil as claimed in Claim 2 wherein said ashless dispersant is a polyisobutenyl succinimide of an ethylene polyamine having the formula H₂N-(CH₂ CH₂ NH)_nH wherein n is an integer from one to ten or mixtures thereof and said polyisobutenyl has a molecular weight of 700-5,000.

4. A quench oil as claimed in Claim 2 or Claim 3 wherein said antioxidant is an alkylated diphenylamine.

5. A quench oil as claimed in Claim 4 wherein said alkylated diphenylamine is di(nonylphenyl)amine.

6. A quench oil as claimed in any one of Claims 2 to 5 wherein said alkaline earth metal detergent is a calcium arylsulfonate.

7. A quench oil as claimed in any one of Claims ₂ to 5 wherein said alkaline earth metal detergent is a calcium phosphonate phenate.

8. A quench oil concentrate comprising a mineral oil solvent containing (a) about 25 to 60 weight percent of ashless dispersant which is one or more of (i) a polyisobutenyl succinimide of an alkylenepolyamine, (ii) a polyisobutenyl succinic ester of an alcohol containing 1-20 carbon atoms and 1-6 hydroxy groups, (iii) a polyisobutenyl succinic ester-amide of a mixture of (x) one or more amines containing 2-10 carbon atoms and 2-10 amine nitrogen atoms, and (y) one or more alcohols containing 1-20 carbon atoms and 1-6 hydroxy groups and optionally 1-4 amine nitrogen atoms, and (iv) a Mannich condensate of a polyisobutylphenol, formaldehyde, and an amine containing 1-20 carbon atoms and 1-10 amine groups at least one of which is a primary amine group, (_b) 2 to 15 weight percent of alkaline earth or alkali metal detergent which is one of more of an alkaline earth metal arylsulfonate, alkali metal arylsulfonate, alkaline earth metal alkylphenate, alkaline earth metal sulfurized alkylphenate or an alkaline earth metal phosphonate phenate and (c) about 1 to 20 weight percent of ashless antioxidant which is one or more of (i) a sterically hindered phenol, (ii) an alkylated aromatic amine or (iii) a sulfurized alkylpehnol. 1

9. A concentrate as claimed in Claim 8 wherein said ashless dispersant is a polyisobutenyl succinimide of an ethylene polyamine having the structure H₂N-(CH₂ CH₂ NH)_nH wherein n is an integer from one to ten or mixtures thereof and said polyisobutenyl has a molecular weight of about 700 - 5,000 and said ashless antioxidant is an alkylated diphenyl amine.

10. A concentrate as claimed in Claim 9 wherein said alkylated diphenylamine is di(nonylphenyl)amine.

11. A concentrate as claimed in any one of Claims 8 to 10 wherein said alkaline earth metal detergent is a calcium phosphonate phenate.

12. A method of heat treating a ferro-metal, said method comprising heating said metal to an elevated temperature and then quenching the heated metal in a quench oil, said quench oil comprising a major amount of mineral oil and

(a) about 0.3 - 7.5 weight percent of ashless dispersant which is one or more of (i) a polyisobutenyl succinimide of an alkylenepolyamine, (ii) a polyisobutenyl succinic ester of an alcohol containing 1-20 carbon atoms and 1-6 hydroxy groups, (iii) a polyisobutenyl succinic ester-amide of a mixture of (x) an amine containing 2-10 carbon atoms and 2-10 amine nitrogen atoms and (y) an alcohol containing 1-20 carbon atoms and 1-6 hydroxy groups and optionally 1-4 amine nitrogen atoms, and (iv) a Mannich condensate of a polyisobutylphenol, formaldehyde, and an amine containing 1-20 carbon atoms and 1-10 amine groups at least one of which is a primary amine group;

(b) 0.02 - 2.5 weight percent of alkaline earth or alkali metal detergent which is one or more of an alkaline earth metal arylsulfonate, alkali metal arylsulfonate, alkaline earth metal alkylphenate, alkaline earth metal sulfurized alkylphenate or alkaline earth metal phosphonate phenate, and (c) 0.01 - 2.0 weight percent of ashless antioxidant which is one or more of (i) a sterically hindered phenol, (ii) a alkylated aromatic amine, or (iii) a sulfurized alkylphenol.

13. A'method as claimed in Claim 12 wherein said ashless dispersant is a polyisobutenyl succinimide of an ethylenepolyamine having the structure H₂N (CH₂ CH₂NH)_nH wherein n is an integer from one to ten or mixtures thereof and said polyisobutenyl has a molecular weight of about 700 - 5,000.

14. A method as claimed in Claim 12 or Claim 13 wherein said antioxidant is an alkylated diphenylamine.

15. A method as claimed in Claim 14 wherein said antioxidant is di(nonylphenyl)amine.

16. A method as claimed in any one of Claims 12 to 15 wherein said alkaline earth metal detergent is a calcium arylsulfonate.

17. A method as claimed in any one of-Claims 12 to 15 wherein said alkaline earth metal detergent is a calcium phosphonate phenate.

18. A quench oil composition comprising a major amount of mineral oil containing about (a) 0.3 - 7.5 weight percent of a polyisobutenyl succinimide of an ethylenepolyamine having the formula H₂N (CH₂CH₂NH)_nH wherein n is an integer from 1 to 10 or mixtures thereof and wherein said polyisobutenyl group has a molecular weight of 700 - 5,000 and (b) about 0.05 - 2.5 weight percent of a sulfurized alkylphenol.

19. A quench oil concentrate comprising a mineral oil solvent containing (a) 15 to 60 weight percent of a polyisobutenyl succinimide of an ethylenepolyamine having the formula H₂N (CH₂CH₂NH)_nH wherein n is an integer from 1 to 10 or mixtures thereof and wherein said polyisobutenyl group has an average molecular weight of 700 - 5,000 and (b) 5 to 25 weight percent of a sulfurized alkylphenol.

20. A quench oil concentrate as claimed in Claim 19 wherein said sulfurized alkylphenol is sulfurized nonylphenol.

21. Articles fabricated at least in part from a metal which has been quenched from an elevated temperature in a quench oil as claimed in any one of claims 1 to 7 or 18.