DE1270064B - Oil for quenching heat-treated metal alloys - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

C21d

German KL: 18 c - 1/58

Number: 1 270 064

File number: P 12 70 064.0-24

Filing date: March 17, 1961

Opening day: June 12, 1968

Many metal alloys, in particular iron alloys need to achieve the necessary hardness to a heat treatment (eg., At a temperature of 85O ⁰ C) with subsequent rapid cooling be subjected. The hardness of an alloy mainly depends on the formation of a specific physical structure. In the case of steel, the hardness is determined by the proportion of martensite formed during the hardening process. Rapid cooling of the alloy is usually done by immersing the hot alloy in a relatively cold quenching liquid. A widely used quenching fluid is mineral oil, but for certain alloys, such as high-carbon, low-alloy steels, pure mineral oils are not a satisfactory quenchant because the initial cooling rate is too slow. A higher initial cooling rate can be achieved by using water as a quenchant, but water is disadvantageous for large parts because it cools the metal too quickly at the lower temperatures and often causes warping and cracking.

It is known in particular to use an oil when quenching steel, the surface as active, organic substances, e.g. B, glycols or other polyoxy compounds are added. In contrast an improved oil for quenching heat-treated metal alloys has now been developed, which is particularly suitable for high-carbon, low-alloy steels and other alloys that are used in simple Mineral oil cannot be cooled properly.

The invention relates to an oil for quenching the heat-treated metal alloys, consisting of a lubricating oil base having a flash point above 177 ° C and a Redwood I-viscosity at 6O ⁰ C of not more than 100 seconds, up to 10 weight percent of an oil soluble Polyoxyaluminiumacylats or contains an aluminum glycolate,

As the lubricating oil, a refined mineral lubricating oil obtained by distillation is preferably used obtained from crude oil. The viscosity of the quench oil should preferably be 30 to 75 Redwood I seconds at 60 ° C. When the aluminum compound tends to increase the lubricating oil thicken, so this tendency by using an anti-gelling agent, z. B. of 8-hydroxyquinoline, be counteracted.

The amount of the oil-soluble aluminum compound dissolved in the lubricating oil is not more than 10% by weight and is, for example, 0.5 to oil for quenching heat-treated
Metal alloys

Applicant:

The British Petroleum Company Limited, London

Representative:

Dr.-Ing. A. ν. Kreisler, Dr.-Ing. K. Schönwald,

Dr.-Ing. Th. Meyer

and Dipl.-Chem. Dr. rer, nat. J. F. Fues,

Patent Attorneys, 5000 Cologne 1, Deichmannhaus

Named as inventor:

Michael George Billett,

James Gibson,

Sunbury-on-Thames, Middlesex (Great Britain)

Claimed priority:

Great Britain March 18, 1960 (9643)

Percentage by weight, based on the weight of the finished mass,

A preferred class of aluminum compounds are the polyoxoaluminum acylates. These compounds can be prepared by heating aluminum alcoholates with water and carboxylic acids in one or more stages, and preferably in an inert, non-volatile diluent such as light lubricating oil. This method of manufacture is described in British patent specification 825,878. Another method is used for production by heating aluminum alcoholates with carboxylic acids alone, whereby alcohol is liberated and acyloxyaluminum alcoholate compounds are formed which are further heated. This method of manufacture is described in British patent specification 806113. Examples of such polyoxoaluminum acylates are compounds of the average general formula (OAlX) ₇₁ , in which η is an integer of more than 1, preferably of

809 559/323

2 to 10, and X is an acylate group, i. H. is a group of the formula RCOO - in which R is aliphatic or aromatic hydrocarbon radical or substituted hydrocarbon radical, in particular one saturated or unsaturated alkyl or aryl radical having 6 to 30 carbon atoms. Particularly preferred are compounds in which the acylate groups from benzoic or salicylic acid or aliphatic Monocarboxylic acids having 12 to 20 carbon atoms, e.g. B. stearic or oleic acid. Of course, the acylate groups in any given molecule of the additive can be the same or different and the additive can consist of a mixture of different molecules.

The other suitable class of oil-soluble aluminum compounds are the aluminum glycolates.

distance Vickers hardness number Probein OilQl from the short edge Sample in oil L deterred of the cut, mm deterred 380 0 380 378 2.54 377 375 5.08 368 372 7.62 355 370 10.16 343 370 12.70 335 369 15.24 325 370 12.70 335 370 10.16 343 372 7.62 355 375 5.08 368 378 2.54 377 380 0 380

example 1

A hardness test was carried out on samples of file steel (low-alloy steel with 1.23 percent by weight Carbon) made in a simple mineral lubricating oil and using of the same lubricating oil made according to the invention had been cooled.

The simple mineral lubricating oil (hereinafter referred to as "OIL") came from the vacuum distillation of a Middle Eastern crude and had been subjected to the normal refining treatment, ie dewaxing, solvent refining with furfural and bleaching earth treatment. The refined oil had a Redwood I-viscosity of 50 seconds at 60 ° C and a flash point of 204 ⁰ C.

The quenching oil according to the invention (hereinafter referred to as "O1Q1") was prepared by adding 3% by weight of an oil-soluble compound M to the above-mentioned lubricating oil. The aluminum compound M was prepared as follows: Aluminiumisopropoxyd was charged with commercial oleic acid in a molar ratio of 1: 2 at up to about 220 ⁰ C rising temperature. 2 molar fractions of isopropanol distilled off during the reaction, towards the end of which a slight vacuum was applied in order to remove the last traces of isopropanol. It is assumed that the product (M) from a solution of 1 part by weight of a polyoxoaluminum acylate of the general formula (OAlOOCR ₁ ) K, in which R _{1 is} an oleyl radical and η is a number from 2 to 10, predominantly 3, in 1 part by weight of isopropyl oleate consists.

Samples of files steel of 0.75 x 3.6 x 11.4 cm V were heated for ₂ hour in an electric oven at 800 ⁰ C and then quenched by immersing them in 22.751 of the coolant at room temperature. The quenched specimens were then severed somewhat off-center on a water-cooled cutting disc to give a cross-section which was ground down to a center line, polished and then tested for hardness using the well-known Vickers hardness tester. The hardness profile was measured at intervals of 2.54 mm along a line that ran centrally across the cut on its two longer sides. All tests were carried out in duplicate. The results are shown in the table below.

It can be seen that by using the quench oil according to the invention, a product was obtained that had a much more uniform hardness across its cross-section than when used of the lubricating oil without additives.

_a _ example2

The initial cooling rate of the oils Ql and L and of an oil Z, which is commercially available as a rapid hardening oil, were determined by a test on a nickel ball. The well-known property of metals has been exploited here, namely that they lose their magnetism when they are heated above a certain temperature value (the Curie point), which is characteristic of every metal. Nickel was chosen for these quenching tests because it does not scale and has tear resistance during quenching. The test method consisted essentially in the fact that a nickel ball in a tubular oven to 85O ⁰ C. and was then quenched in oil. The time it took for the ball to become magnetic gave an accurate measure of the quench rate from 850 to 354 ° C (the Curie point of nickel). The following results were obtained:

Oil Ql 15.5 seconds

Oil L 22.7 seconds

Oil Z 19.3 seconds

It can be seen that from the standpoint of high

Initial cooling rate according to the quenching oil

invention was the best of the oils tested.

Example 3

Some chain links of various sizes, made of chrome nickel steel with 0.4 to 0.5 weight percent C, 1.2 weight percent Ni and 1.8 weight percent Cr, were in the additive mineral lubricating oil L and in a quenching oil according to the invention (Q 2 ), which was prepared by dissolving 5 percent by weight (based on the final mixture) of compound M in lubricating oil L. The curing device consisted of a conveyor belt, which resulted in the chain links by one held at 850 ⁰ C furnace, where they remained for about 10 minutes before they cm at a distance of 30 fell into the kept at 6O ⁰ C quench bath. Tests of the treated chain links for the Rockwell hardness C showed that the smaller chain links (about 12.7 mm long) were used

45

Q of the oil 2 was obtained an increase in the surface hardness by 15% compared to i ^m L oil. The larger chain links (30.5 cm long, 10 cm wide, 12.7 mm thick) achieved a 10% greater surface hardness. In some smaller links that were cut, an even distribution of hardness was found across the cross-section.

Example 4

Some silicon-manganese spring steel stampings (for a refrigerator temperature controller) with a carbon content of 0.6 to 0.7 percent by weight were quenched in the additive-free mineral lubricating oil L and in the quenching oil Q 2 according to the invention. The pieces were punched out under hydrogen through a held at 900 ⁰ C electrically heated furnace and arranged in a downstream of the furnace, dropped with the quench oil filled tank. The tank contained 1821 oil that had a temperature of 60 to 70 ^0C . When quenching in oil L, a hardness of 530 to 670V.PN (Vickers Pyramid Number) was achieved. Hardness values on the order of 750V.PN were obtained with oil Q 2. This corresponds to the value obtained when the stampings were quenched in water.

Claims (3)

Patent claims: 1. Oil for quenching heat-treated metal alloys, consisting of a lubricant oil-based with a flash point above 177 ° C and a Redwood-I viscosity at 60 ° C of not more than 100 seconds, which is up to 10 percent by weight an oil-soluble polyoxyaluminum acylate or an aluminum glycolate. 2. Quenching oil according to claim 1, characterized in that the lubricating oil base has a Redwood I viscosity at 60 ° C in the range of 30 to 75 seconds, which is a mineral lubricating oil obtained in the distillation of petroleum acts, the 0.5 to 5 percent by weight of an oil-soluble polyoxyaluminum acylate or contains an aluminum glycolate. 3. Quenching oil according to claims 1 and 2, characterized in that it contains polyoxyaluminum acylates of the average general formula (OA1X) _M in which η is the number 2 to 10 and X is an acylate radical of the general formula RCCOO -, where R is a saturated or is unsaturated alkyl or aryl radical with 6 to 30 carbon atoms and wherein X is also in particular one of benzoic acid, salicylic acid or aliphatic monocarboxylic acids with 12 to 20 carbon atoms, e.g. B. stearic acid or oleic acid, means derived radical. Considered publications:
German patent application C 8097 VI a / 18 c (published on July 28, 1955); British Patent No. 825 878. 809 559/323 5.65 ® Bundesdruckerei Berlin