CS252448B1 - Lubricant for cold forming of metal, in particular for balding of foals and foils - Google Patents

Abstract

The solution relates to a lubricant for cold forming of metals, in particular for rolling sheets and foils, the main feature of which is that it contains 80 to 99% by weight of an oil base with a maximum value of the end temperature of distillation of 360 °C at atmospheric pressure, which contains a maximum of 15% by weight of unsaturated components and the content of condensed aromatic components is lower than 3% by weight, which oil base contains at least 80% by weight of oxyclano-paraffinic fraction and has an open cup flash point of at least 85 °C and a pour point lower than 8 °C, the lubricant further containing 1 to 20% by weight of synthetic esters of mono- or dicarboxylic acids with a number of carbons in the molecule '4 to 24 with mono- or polyfunctional alcohols with a number of carbons in the molecule 2 to 18, the ester used being an organic individual, and 0.1 to 2% by weight of alcohols with a number of carbons in the molecule 7 to 18.

Description

The invention relates to a lubricant for cold forming of metals, in particular for rolling sheets and foils.

A number of products are currently used for the forming of ferrous and non-ferrous metal materials. One group of products consists of products based on petroleum or synthetic oils, the other group consists of aqueous emulsions of these materials. In order to ensure the desired effect, especially lubricating and cooling capabilities, anti-corrosion protection, oxidation stability and bacteriostatic efficiency, various types of additives are added to most of the products used.

For a number of special products, such as thin sheets and foils, intended for the pharmaceutical and food industries, it is technologically advantageous and sometimes necessary to anneal these materials without prior degreasing. The purpose of annealing is to achieve suitable mechanical properties of the materials and at the same time to remove lubricant residues from their surface as completely as possible. Most of the lubricants known to date do not allow the desired surface cleanliness to be achieved after annealing, because the very nature of the oils and mixed additives used to date does not allow their complete evaporation. The use of aqueous emulsions is more advantageous in terms of non-evaporable residues, but their lubricating properties are usually not suitable for more demanding forming operations.

The precursors of the formation of residues after annealing in lubricants known to date are mainly unsaturated components of used oils and additives, organically bound metals in additives, temperature-labile compounds of sulfur, chlorine, phosphorus and nitrogen, which are used as high-pressure and anti-corrosion additives. Natural substances used as refining additives also generally have a negative effect.

The above-mentioned shortcomings are solved by the lubricant according to the invention for cold metal forming, especially for rolling sheets and foils and for special forming operations. The essence of the invention lies in the fact that the lubricant according to the invention contains 80 to 98.9% by weight of the oil base. This oil base has a maximum value of the end temperature of distillation of 3'6O °C. For less precise forming operations, a distillation range of 160 to 340 °C is advantageous, and a distillation range of 210 to 270 °C is suitable for dimensionally precise forming operations and for rolling thin foils used in the food industry. The maximum content of unsaturated components in the oil base does not exceed 15'% by weight and the content of condensed aromatic components is. lower than 3% by weight. The oil base contains at least 80% by weight of the cyclane-paraffinic fraction. The ratio of cyclanes. to paraffins guarantees a freezing point lower than -8 °G. The oil base has an open cup flash point of at least 85 °C. Other components of the lubricant according to the invention consist of 1 to 19.9% by weight of synthetic esters of mono- or dicarboxylic acids with a number of carbons in the molecule of 4 to 24 with mono- and polyfunctional alcohols with a number of carbons in the molecule of 2 to 18, the ester used being a chemical individual. Furthermore, this mixture contains 0.1 to 2% by weight of alcohols with a number of carbons in the molecule of 7 to 18. When used in continuous operation for more than one year, it is advantageous to add an ashless antioxidant additive to the composition, preferably di-tert-butyl-p-cresol or octadecylamine in an amount of 0.1 to 0.5% by weight. This mixture of mineral and synthetic oil guarantees excellent lubricating properties, long bath life and high oxidation stability.

The lubricant according to the invention does not leave traces on the formed surface after annealing at temperatures commonly used in technology. This is guaranteed by the use of a petroleum fraction with a final distillation temperature, an open cup flash point and, in particular, a limited content of condensed aromatic components, which guarantees quantitative removal of lubricant residues by annealing the formed material.

For the same reason, it is important that the ester used is a chemical individual with a distillation range of maximum 6 °C. The presence of alcohols has a positive effect on the stabilization of esters under forming conditions and at the same time alcohols improve the appearance of the material after annealing /see table/.

- 5 The use of pure esters in lubricants in terms of their removal from the metal surface after annealing is documented in the table.

*· '

Table

Surface quality of sheets after coil annealing using various additives based on carboxylic acid esters

Sample Rolled material annealing temperature area of dark spots on the sheet metal in % of the surface bis/2-ethyIhexal/ adipate /BEHA/ aluminum 450°C isobutyl stearate /IBS/ aluminum 450°C base oil A + 5% wt. BEHA aluminum 450°C 2 base oil A + 5% wt. BEHA + 0.1% wt. decanol aluminum 450°C 0.5 base oil B + 5% wt. IBS steel 860°C 1 to 2' base oil B + 5'% wt. IBS + steel 860°C 0.5

% mass of alcohol Cq_]j

lanolin steel 860°C 58 rapeseed oil steel 860°C 80 base oil B + 5% w/w lanolin steel 860°C 60 base oil B + 5% by weight rapeseed oil steel 860°C 80

esterification product of stearic acid and a mixture of alcohols

C7 to 9 /Ester 1/ aluminum 450°C . 25 esterification product of acids . 1 maleic and alcohol mixtures • Cg to 11 /Ester 11/ aluminum . 450°C .50 base oil A + 5% wt. Ester I aluminum 450°C 20 base oil A + 5% by weight of Ester II aluminum 450°C 2Σ

- 4 Steel material, grade 17 266, aluminum material - alloy

99.5% Al, 0.5% Mg· Base oil A - hydrogenate with a distillation range of 210 to 270 °C, base oil B - hydrogenate with a distillation range of 180 to 340 °C.

The invention and its effects are illustrated in more detail in the following examples of its implementation.

Example 1.

A mixture consisting of 80% by weight of hydrogenated mineral oil distillate with a distillation range of 180 to 340°C and a viscosity of 7.1 m m/s at 50°C, 18% by weight of isobutyl stearate with a distillation range of 340 to 345°C, 1.5% by weight of a mixture of C9 to C11 alcohols and 0.5% by weight of di-tert-butyl-p-cresol was homogenized at a temperature of 40°C. The resulting mixture with a flash point of

160 °C and a solidification temperature of -12 °C was used for rolling iron sheets of material class 12017 and a thickness of 0.5 mm on a 3-roll stand to a final thickness of 0.1 mm. After annealing the rolled material without degreasing, the area of darker spots was less than 5%, while when using standard oils under the same conditions, its area was more than 50%.

Example 2

A mixture consisting of 98.9% by weight of the hydrogenated base according to Example 1 and 1% by weight of isobutyl stearate and 0.1% by weight of 2-ethylhexanol was homogenized at normal temperature. This mixture had a flash point of 145°C and a pour point of -10°C.* When rolling 2 mm thick aluminum sheets and at a 50% reduction in thickness, the surface of the sheet after rolling and annealing is completely shiny over the entire surface. However, this lubricant used in rolling iron sheets has a shorter service life.

Example 3 · . .

A mixture containing 85% by weight of the oil base according to Example 1, further 13% by weight of bis-(2-ethylhexyl)adipate, 1.5% by weight of n-decanol and 0.5% by weight of octadecylamine was homogenized at 50°C. The lubricant thus prepared had a flash point of 163°C and a pour point of -12°C and was used in the rolling of steel sheets of material classes 11 and 12 on a 12-roll mill.

252448 .

- 5 mills lubricated by central distribution with an input sheet thickness of 3 mm, output thickness of 0.8 mm. The lubricant showed high stability and service life with satisfactory sheet quality.

Example 4

A mixture consisting of 96.9% by weight of a distillation cut of hydrogenated light oil with a kinematic viscosity of at least

1.5 mm^s"· ¹ · at 50 °C, flash point of at least 85 °C, distillation range 210 to 270 °C and 3 wt. % bis-(2-ethylhexyl)adipate and 0.1 wt. % 2-ethylhexanol were homogenized at room temperature. This lubricant is particularly suitable for rolling aluminum sheets and foils, especially for food purposes. The flash point of the lubricant is 9.8 °G and the pour point is -15 °C. Example 5

A mixture containing 94.7% by weight of the distillation cut according to Example 4 and further 4.9% by weight of bis-(2-ethylhexyl)adipate, 0.1% by weight of di-tert-butyl-p-cresol and 0.3% of 2-ethylhexanol was homogenized at room temperature. This lubricant is particularly suitable for rolling aluminum sheets and reflective foils in continuous operation of the rolling mill. This lubricant has a flash point of 103°C and a pour point of -15°C. . i

Claims (2)

PLEASE GO Τ IN PA 1. Lubricating agent for cold forming metals, in particular for the rolling of sheets and foils, characterized in that it contains 80 to 98.9% by weight of an oil base having a maximum distillation end temperature value of 360 [deg.] C. at atmospheric pressure and containing at most 15 9 'wt. unsaturated constituents and the condensed aromatic content is less than 3% by weight, the oil base of which comprises at least 80% by weight. cyklanicko _T -parafinického moiety and has a flash point in the open kelínpku least 85 ° C and a pour point of less than -8 ° C, the lubricating composition further comprises from 1 to 19.9% by weight. % of synthetic mono- or dicarboxylic acid esters having a carbon number of 4 to 24 with mono- or polyhydric alcohols having a carbon number of 2 to 18, the ester used being a chemical individual, and 0.1 to 2 wt. of alcohols having a carbon number of 7 to 18. .2. 3. Lubricant according to claim 1, characterized in that it contains 0.1. % to 0.5 wt. antioxidants, preferably di-tert-butyl-p-cresol or octadecylamine.