SU1250340A1 - Method of preparing steel wire for drawing - Google Patents

Description

The invention relates to ferrous metallurgy, in particular to the hardware industry, and can be used in preparing the surface of steel wire for drawing.

The purpose of the invention is to improve working conditions and reduce dragging.

The drawing shows a process flow diagram of the preparation of the surface of the wire before drawing on the proposed method.

Steel wire 2 enters the heating furnace 1. The latter moves in a tubular muffle 3 consisting of three sections: perforated a, holding b, cooling c. Through the inlet 4 of the endothers. According to the proposed method, the cooling of the steel wire billet (normalization) is carried out in a refrigerator in the direction of flow of the reducing gas and the wire, on the surface of which there is no oxide film. Feeding endogas to the initial part of the cooler contributes to a more rapid cooling of the wire and prevents the wire from oxidizing.

To provide a countercurrent engine 10 for reducing endothermic gas in the austenitization zone of the wire (section b) and its direct movement in the refrigerator (section c), the supply of the reducing gas to the tubular muffle is dried at the junction of the sections. tion and refrigerator. In accordance with fractions b and the area in muffle 3. After section b, the endogas enters the area a, where its afterburning is dried.

The wire is unwound from the coil 5 and enters the section a of the muffle 3, where it is heated in the oxidizing atmosphere of the endogas combustion products. Getting to the site b muffle, the wire is kept at austenization temperature in countercurrent of endogas. On the site in the wire cool20

For safety when working with explosive gases, the tubular muffle is purged with an inert gas before and after stopping the endogas supply. The supply of endogas to the muffle is allowed only after the working temperature in the furnace space of the thermoelectric unit is reached and during the operation of the igniter at the gas outlet from the refrigerator.

According to the proposed method, a chemical is supplied in the endogas flow, which is burned on the 25 thermal surface preparation of the muffles from the muffle using a pilot 6.

The wire is oxidized in the temperature range of 500-920 ° C.

At temperature below 500 ° C oxidation

The LEI of the wire to the drawing operation of the acid etching of the metal is eliminated due to the absence of scale on the surface of the wire after it is kept in the atmosphere of the reducing gas with 30 austeal wire billets occurring and cooling.

with a slow speed in the atmosphere of flue gases with the formation of a small thin layer of oxide film.

The implementation of the oxidative surface treatment of the wire in the perforated

Verification of the proposed method carried out in industrial conditions.

The workpiece was normalized to a diameter of 3.2 mm from steel 70 with the preparation of the surface chemical-thermal

muffle zone, equal to about a quarter 35 way and drawing it to a diameter of 1.25 mm.

A billet with a diameter of 3.2 mm was heated in a continuous furnace to a temperature of 900– 920 ° C. In this case, conditions were created when the initial portion of the furnace was

the length of the furnace space of the furnace unit, and the subsequent reduction of the oxide surface of the wire in the environment of the reducing endothermic gas during the austenization of the wire allows the oxidation zone. Here, the surface should form a given surface microrelief, which ensures the capture of the sub-lubricant layer during the drilling or phosphating of the wire before it is drawn.

The use of endogas provides dragging out covered with a layer of oxides, and then the wire enters the recovery zone, into which a reducing endothermic gas is fed by countercurrent with respect to the movement of the wire.

low and stable carbon potential 45 of the following composition,%: CO 13-16; SOZ 2-4;

atmosphere in the recovery zone.

The countercurrent movement of the wire and reducing gas during the austenization of the wire and the reduction of the oxide layer on its surface (section b) 50 provides an increase in the degree of reduction of the oxide layer and a more complete use of the reducing power of endogas. At the entrance to the reaction zone, endogas has the highest reduction potential, and then along the motion of the gas phase it is enriched with reduction products — H20 and CO2.

55

H2 36-38; H2O 5-8; N2 40-42. Next, the wire was cooled in the reducing gas, and then entered the bath with borax.

Technological characteristics of the process of normalization with the preparation of the surface of the proposed method in comparison with the known are given in table. one.

The dragging process was stable on the 630/9 type frame. The indicators of the process of drawing blanks with surface preparation by the proposed method and the basic technology are comparable with each other.

According to the proposed method, the cooling of the steel wire blank (normalization) is carried out in a refrigerator in the direction of flow of the reducing gas and the wire, on the surface of which there is no oxide film. Feeding endogas to the initial part of the cooler contributes to a more rapid cooling of the wire and prevents the wire from oxidizing.

In order to provide countercurrent movement of the reducing endothermic gas in the austenization zone of the wire (section b) and its direct movement in the refrigerator (section c), the supply of the reducing gas to the tubular muffle is carried out at the junction of the austenization sections and the refrigerator. In accordance with potion and refrigerator. In accordance with the rules

For safety when working with explosive gases, the tubular muffle is purged with an inert gas before and after stopping the endogas supply. The supply of endogas to the muffle is allowed only after the working temperature in the furnace space of the thermoelectric unit is reached and during the operation of the igniter at the gas outlet from the refrigerator.

According to the proposed method of chemical heat treatment of the steel wire surface to the drawing of the acid etching of the metal is excluded due to the absence of scale on the wire surface after it is held in the atmosphere of the reducing gas during austerization and cooling.

nizatsiya and cooling.

Verification of the proposed method carried out in industrial conditions.

The workpiece was normalized to a diameter of 3.2 mm from steel 70 with the preparation of the surface chemical-thermal

way and drawing it to a diameter of 1.25 mm.

 oxidative zone. Here, the surface of the wire was covered with a layer of oxides, and then the wire entered the reduction zone, into which a reducing endothermic gas was fed by countercurrent with respect to the movement of the wire.

 the following composition,%: CO 13-16; SOZ 2-4;

the following composition,%: CO 13-16; SOZ 2-4;

H2 36-38; H2O 5-8; N2 40-42. Next, the wire was cooled in the reducing gas, and then entered the bath with borax.

Technological characteristics of the process of normalization with the preparation of the surface of the proposed method in comparison with the known are given in table. one.

The dragging process was stable on the 630/9 type frame. The indicators of the process of drawing blanks with surface preparation by the proposed method and the basic technology are comparable with each other.

At the same time, the metal according to the proposed method has the best plastic properties, which is characterized by large values of the work hardening coefficient (Table 2).

Improving the plastic properties of the metal,

of the decarburized layer on its surface. At the same time, the dragging force is reduced by 31% compared to the base.

The exclusion of acid etching from the number of technological operations improves the conditions and the ability to deform the labor of workers in the workshop and reduces the metal with surface preparation, the offer of discharged harmful impurities.

in the environment.

This is due to the presence

Coefficient

work hardening

Also

Base

Proposed

Base

0.44 1.21 1.28 0.41 1.60 1.10 0.70 0.74 1.0

0.48 0.39 0.31 0.27 0.19 0.15 0.08 0.05 0.34 0.28 0.28 0.19 0.18 0.14 0.08 0.04

of the decarburized layer on its surface. At the same time, the dragging force is reduced by 31% compared to the base.

The exclusion of acid etching from the number of technological operations improves the working conditions of the workshop workers and reduces the number of discharged harmful impurities.

Table 1

table 2

Claims (1)

METHOD FOR PREPARING THE SURFACE OF A STEEL WIRE TO DRAWING, including heating the wire to an austenitizing temperature, holding it at that temperature and subsequent cooling of the wire, characterized in that, in order to improve working conditions and reduce the drawing force, the steel wire is heated to an austenization temperature in an oxidizing atmosphere, holding at the austenitization temperature is carried out in countercurrent of the endothermic reducing gas, and the subsequent cooling of the wire is carried out in the direct flow of the endothermic recovery of glancing gas. 12503