SU891763A1 - Grease for hot rolling of pipes - Google Patents

Description

(54) LUBRICANT FOR PIPE ROLLS

The invention relates to the processing of metals by pressure, in particular to technological lubricants, and can be used during hot rolling of pipes. The following compositions of inorganic compounds based on sodium tripolyphosphate and calcium oxide, a mixture of phosphates, salts of boric acid with cobalt zinc sulfides, calcium fluoride, sodium and graphite GP and f2 are known. However, all of these lubricants have an insufficient lubricating and screening ability, therefore risks and tears are formed on the rolled surface and tears quickly wear out of the mandrels. A known hot rolling pipe lubricant, which is powdered sodium tripolyphosphate Gz. However, this lubricant does not provide a high quality surface to be treated - risks are on the inner surface of rolled pipes, and mandrels wear out quickly because the lubricant has insufficient lubricity. The purpose of the invention is to create a lubricant that allows improving the quality of the inner surface of pipes, increasing the tool durability, and reducing rolling forces. The goal is achieved by the fact that the lubricant based on the sodium salt of phosphoric acid additionally contains slag of burning coal dust and as the sodium salt of phosphoric acid the lubricant contains hexametaphosphate and / or sodium tripolyphosphate with the following content of components, wt.%: Slag of burning coal dust 5-20 Hexametaphosphate and / or sodium tripolyphosphate 80-95

Slag is a waste of burning coal dust in the furnaces of thermal power plants. Dispersity of slags is 0.005-0.05 mm.

Prepared and tested compositions of lubricants, which are shown in table 1

Lubricants are prepared as follows.

Technical hexametaphosphate and / or sodium tripolyphosphate are ground in a ball mill to a particle size of, for example, 0.01-0.05 mm and mixed with slag. The finished mixture is sprayed onto the inner surface of the pipe, having a rolling temperature of 1100-1150 ° C before rolling or during the rolling process.

Testing of lubricants was performed on an industrial automatic machine when rolling pipes with a diameter of 114 mm with a wall thickness of 4 mm, with a drawdown of 2, at a rolling speed of 3 m / s.

The effectiveness of the lubricant is evaluated according to the following parameters:

the power force indicator, which is determined by the flow of the main engine of the mill and is measured by an oscilloscope;

the quality of the inner surface of the pipe, which was evaluated visually by the number of scratches and scoring on the surface;

the resistance of the mandrels, which is estimated by the number of tubes rolled on one mandrel, within the tolerance

Composition

Sodium hexametaphosphate 99 Sodium tripolyphosphate Shpak coal combustion

rolled 300

rolling 34

Parallel rolled pipes for lubrication by a known method.

Comparative rolling data are presented in table 2.

From Table 2 it follows that the proposed composition allows the IJTO to reduce energy-power parameters by 17%, to improve the quality of the internal surface (the output of pipes without scratches and burrs increased

29 times and increase the durability of certificates 2 times.

Increasing or decreasing the concentrations of lubricant components (composition 1 and 5} causes a deterioration in the quality of the inner surface, the number of pipes with bulges and risks increases 10-15 times, the durability of the mandrels decreases 1.7-2.2 times and the power parameters increase to 14% .

Comparative results of pipe rolling with the proposed and known lubricant compositions are given in Table 2.

Thus, the proposed lubricant can improve the quality of the inner surface of pipes. The yield of pipes with the required surface cleanliness increased 29 times. The durability of the mandrels is doubled. The power parameters are reduced by 17% and the mill productivity is increased by 5-7%.

Table 1

Component concentration, wt.%

2 3 45 Known

90

thirty

95

50 70

100

300 300 300 300 300

47 87

3 3

Number of rolled tubes on one mandrel81 Current of the electric motor box, A

Claims (3)

1. USSR author's certificate number 316764, cl. C 10 M 1/04, 1971. 2. The patent of France No. 2158191, cl. From 10 M 7/00, 1973. 3. USSR author's certificate No. 324086, cl. C 10 M 7/42, 1972 (prototype). 290. 340 350