CS241907B1 - Grease paste for rolling alloyed steel materials - Google Patents

Abstract

The lubricating paste for rolling alloy steel materials according to the invention contains 55 to 70 wt. % halogenated hydrocarbons, preferably chlorinated paraffins with a chlorine content of at least 55 wt. % and an average number of carbon atoms in the hydrocarbon chain C20 to C58» 10 to 15 wt. % vegetable oil, preferably castor oil, 12 to 20 wt. % mineral oil and 5 to 30 wt. % inorganic lubricant component.

Description

The invention relates to a lubricating paste for cold rolling of alloy steel tubes.

Cold rolling of steel tubes is currently a widespread operation in the process of manufacturing these tubes. A wide range of lubricants are used for cold rolling and forming of stainless steel tubes and rods, such as conventional solid lubricants or plant-based or mineral-based or synthetic-oil-based compositions and mixtures thereof. These oils have drawbacks which mostly eliminate the use of other types of lubricants containing components having a high affinity for the metal surface and at the same time are high pressure additives of the lubricant used.

In the case of demanding operations, however, these lubricants do not fully satisfy and their lubricating ability must be increased by the addition of solid, usually inorganic substances. Currently, several types of these substances are used, in particular calcium or barium hydroxide, barium and zinc oxide, calcium carbonate and the like. Further, the lubricating properties of these compositions are further improved by the addition of soaps.

Despite the considerable successes of these lubricants in forming and, above all, rolling austenitic materials, they do not fully satisfy all the required operations, especially when it comes to the production of pipes with high internal gloss and minimal material defects. These tubes are mainly used in steam generators for conventional and especially nuclear power plants. The reason for the requirement of high quality of the internal surface is to eliminate the possibility of spot and surface corrosion during operation. Especially point corrosion is very undesirable as it can cause wall weakening to the point of accident.

- 2 241 907

The number of such material defects can be substantially reduced by using the lubricant according to the invention. The lubricating composition according to the invention contains 35 to 70% wt. halogenated hydrocarbons, preferably chlorinated paraffins having a chlorine content of at least 35% by weight and an average number of carbon atoms in the C20 to C18 hydrocarbon chain, 10 to 15% by weight of a vegetable oil, preferably castor oil, 12 to 20% by weight of a mineral oil , 5 to 30% by weight of inorganic lubricant components and 0.1 to 2% by weight of antioxidant and anti-wear additives. It is based on a suitable combination of liquid and solid components. The liquid components of this lubricant are themselves capable of meeting the demanding requirements in conditionally hydrodynamic to ultimate friction. In the area of ultimate friction, the lubricant function assumes the solid lubricant components which, due to their physicochemical properties, ensure a sufficiently low coefficient of friction between the tools and the tubes in the ultimate friction area, neutralize unwanted products . In order to fulfill this function, the inorganic constituents must have a particularly high specific surface area and be represented in suitable proportions with each other.

The composition of the lubricating compositions according to the invention and their properties can be shown in the following examples, and a higher effect of the lubricating compositions according to the invention is demonstrated in a final taoul by comparing the results of the foreign pastes used and lubricating compositions according to the invention.

Example 1 kg of chlorinated paraffins with a chlorine content of 40% by weight, 16 kg of bearing oil B2 and 12 kg of castor oil are added after homogenization at 50 to 60 ° C to a mixture consisting of 19 kg of precipitated calcium carbonate and 1 kg of silica gel particle size of 1 to 2 microns / containing 4% of the hydrogen fluoride sorbed. The mixture is thoroughly mixed and finally calendered. The resulting paste is suitable for dosing into rolling oils intended for internal lubrication when rolling alloy steel tubes.

Example 2

61.75 kg of the chlorinated paraffin of Example 1, 19 kg of vacuum oil and 241 kg of castor oil were homogenized at 50-60 ° C. To this mixture is added 5 kg of a mixture consisting of 2 kg of precipitated calcium carbonate, 1 kg of precipitated calcium hydroxide, 0.5 kg of alumina and 1 kg of magnesium oxide. The paste homogenization can be carried out as in Example 1. The product is suitable for direct lubrication of mandrels when rolling steel tubes.

Example 3 kg of the oil base of Example 1 is added to 30 kg of a mixture consisting of 20 kg of a mixture of calcium oxide and hydroxide and 10 kg of zinc oxide. This mixture is homogenized by calendering. The paste produced can be used for controlled feeding into tubes and rod rolling oils under conditions of high cross-sectional reduction of up to 78%.

Example 4

To 78 kg of the oil base of Example 1 was added 1 kg of zinc dialkyldithiophosphate containing alkyls having a carbon number of C * to C8 and 1 kg of calcium oleate. To this mixture was added 19 kg of calcium carbonate and 1 kg of silica gel + 4% calcium fluoride. The above-described finish of the product produces a paste with excellent anti-wear properties which, when added to the rolling oils, makes it possible to achieve a quality of rolled tubes that exceeds 95% after defectoscopic inspection.

Example 5

To 90 kg of the oil-based composition of Example 1 was added 8 kg of magnesium oxide, 1 kg antioxidants throws 2,6-di-tert-butyl-4-mexhylrenolu and 1 kg of sulfurized calcium alkylphenolate comprising C l to C ₁₂ · The paste It excels in high phase stability even during long-term storage and is used for direct injection into the zone of the forming zone when rolling alloyed tubes.

- 4 Comparison of the results of the operating tests of the lubricants according to Examples 241 907 and the lubricants used in the currently tested reduction of the mandrel service life of the roller.

lubricant, /% / / and & m number of material /% / rollers /.

up to now used zahraň.pasta č.l 70.5 501 58 dos ^ d used foreign paste no.2 70.5 230 • 42 Pasta fillet Ex. 1 70.5 850 82.5 pa hundred fir example. 2 72 610 81 paste pdle ex 3 78 1 230 85 pastapůle 4 75.1 330 95.1 paste of fir eg 5 76.4 668 80

Claims (3)

OBJECT OF THE INVENTION 241 907 1. Grease paste for the rolling of alloyed steel materials, characterized in that it contains 35 to 70% by weight of halogenated hydrocarbons, preferably chlorinated paraffins with a chlorine content of at least 35%, and an average number of carbon atoms in the C20 θ38, 15% by weight oils, preferably castor oil, 12 to 20 wt.% mineral oil and 5 to 30 wt.% of an inorganic lubricant component which is based on carbonates or metal oxides or hydroxides of the second group of the Periodic Table of Elements and alumina or silica an active or hydrated form or calcium fluoride optionally a mixture of two or more of said components thus; wherein the carbonates or metal oxides or hydroxides of the second group or mixtures thereof are present in a weight ratio of 1: 0.05 to 1: 0.5 relative to alumina or silica or calcium fluoride or mixtures thereof, it being preferred that the average particle size of these inorganic The content of free water did not exceed 5% hW of the total amount of inorganic lubricant component. 2. Lubricating paste according to claim 1, characterized in that it contains as a mineral oil a selectively or hydrotreated oil having a viscosity of 15 to 30 mm ² / s at 50 ° C or a mixture thereof. 3. Grease paste according to claim 1, characterized in that it further comprises 0.1 to 2% by weight of antioxidant and anti-abrasive additives which are formed by one or more of the following: 2,6-di-tert-butyl-4 -methylphenol, zinc C4 to C8 dialkyldithiophosphate, calcium oleate, sulfur C8 to calcium phenolate _o