CS200003B1 - Cutting lubricant - Google Patents

Description

( ⁵⁴ ) Cutting fluid

The present invention relates to a cutting fluid particularly suitable for speed grinding of hardened and non-hardened steel.

Efforts to increase the grinding performance have now led to an increase in the peripheral speeds of the grinding wheels, which have on average increased twice, from 30 to 45 m / s to 60 to 90 m / s. Under these conditions, increased demands are placed on the effect of the abrasive fluid, both in terms of lubrication, heat generation and heat dissipation. For example, for speed grinding, it is not possible to use a cutting emulsion fluid that has an excellent cooling effect but a low lubricating effect. When using an emulsion, usually lower grinding removals (mn? / S) and _m θ are achieved, where 0 _m is the volume of the abraded material of lower values of the relative grinding G, where G mra? and 0 ^ is the disc loss volume mn? . Moreover, the relative abrasion G, which determines the durability of the active surface of the wheel, is influenced by the lubricating effect of the abrasive fluid.

So-called high-pressure additives provide lubrication in abrasive fluids. They are usually suitable sulfur, chlorine and phosphorus compounds which are capable of reacting with the metal just being cut at high pressures and temperatures and forming a layer of sulphides, chlorides and phosphides or possibly other compounds on the workpiece surface which facilitate chip removal. The disadvantages of many of the compounds used, such as high pressure liquid additives, are the unpleasant odor and often health problems when used in higher concentrations. One of the widely used ingredients at home and abroad is dihensyl disulfide, which has a good cutting effect, but

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200 003 very pungent and unpleasant odor. For this reason, workers refuse to work with oils containing this substance - in the CSSR they are P2DS and P4DS oils - so about 50% of the total amount where P2DS, P4DS oils should be used for technological reasons is less effective but unattractive. cutting oil P3. Another additive used in oils in Czechoslovakia is eg dispermyldithlophosphate. This additive does not have a significantly unpleasant odor, but its grinding efficiency is low (P3 oil).

The liquid according to the invention, which consists of a mineral oil (viscosity 5 to 35 mm @ 2 / s at 50 DEG C.) of a corrosion inhibitor, of linseed oil and of an active ingredient, is based on the fact that the active ingredient is a mixture of 1 to 15. % wt. % of a chlorinated, n-paraffinic hydrocarbon having a carbon number of more than 25 and having a chlorine content of 35 to 50% by weight; and 0.1 to 5 wt. tetramethylthiuram disulfide.

The cutting fluid according to the invention significantly reduces the cutting forces, for example when grinding hard-to-machine steels. Due to the reduction of the cutting forces, the conoentraoi of heat in the surface layer of the ground material does not occur during grinding, which in other cases is often the cause of cracks and structural changes in the machined surface. The cutting fluid of the present invention significantly reduces abrasive wheel wear compared to other conventional fluids.

An example of the composition of the liquid according to the invention is 40% by weight. % mineral oil whose kinematic viscosity at 50 ° C is 7 to 25 mm s, 20 wt. % of sulfur flaxseed oil containing about 8% sulfur,% wt. % chlorinated paraffin containing 40% chlorine - number of carbon atoms in the molecule above 25% by weight of epoxybutyl ester as a corrosion inhibitor; % tetramethylthiuram disulfide and 2 wt. triethanolamine.

Comparative grinding tests were performed with P3, P2DS oils and the liquid according to the invention on an Oeli 14 109.4 disc A 99 80 M 9 V. The results of the comparison tests are shown in the diagram in the attached drawing and for an equivalent depth of 0.1 in the following table.

cutting fluid • o, i ^{y / mm 3} 0.1 mar / y according to the invention 1 192.0 35.5 5.41 cutting oil 2 177.6 35.5 5.00 cutting oil 3 147 ^ 2 41.0 3.59

The tangential component of the cutting force was chosen as the criterion for the efficiency of individual oils

P ^ depending on the equivalent chip thickness h _9q , speoiflex energy e _Q ^ v Jouleoh consumed for 1 mm grinding? grinding material and relative abrasion The comparative value of the properties of cutting fluids is the efficiency ratio Q

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The greater the value of the efficiency coefficient θ ₁ , the more positive the action of the abrasive oil. Depending on the magnitude of the equivalent chip thickness h__ (i.e. the intensity

The cutting force F ^ was measured from II ιΤ · Βι grinding and at the same time the relative abrasion G ₀ 1 at different equivalent chip thickness h _gq was calculated based on the measurement.

From the diagram in the drawing, it can be seen that the tangenoic component of the cutting force F pro is the same for the cutting oil 2 and the fluid according to the invention over a large test range h. However, the value of relative abrasion is far more favorable for the cutting oil 6 according to the invention than for the oil 2.

This means that when using the liquid according to the invention, a longer shelf life of the disc is achieved and the time for the necessary dressing of the disc is substantially reduced. A substantially greater cutting force F F in grinding than the oil 2 and the liquid according to the invention has oil £ in the entire range of the observed h. The diagrams further show the curves G (í, 2,)) representing the abrasion ratio. £ 3. “* - depending on h for all three fluids tested. The biggest, ie the most favorable course «• Μ *

G has a liquid according to the invention.

Claims (2)

SUBJECT OF THE INVENTION A cutting fluid, particularly suitable for speed grinding and grinding of difficult-to-machine metals, consisting of a mineral oil of a viscosity of 5 to 35 mm / s, a corrosion inhibitor, sulfur flaxseed oil and an active ingredient, characterized in that the active ingredient is a mixture 1 to 15 wt. % of a chlorinated hydrocarbon, n-paraffinic, having a carbon number of more than 25, having a chlorine content of 35 to 50%, and 0.1 to 5% by weight; tetramethylthiuram disulfide. 2. The cutting fluid of claim 1 wherein the active ingredient comprises triethanolamine as a solvent of tetramethylthiuram disulfide, both components in a 1: 1 weight ratio.