JPS59190376A - Direct heat treatment and surface treatment of steel wire rod - Google Patents

Abstract

PURPOSE:To obtain energy and resource economization and to prevent the dispersion of a source for generating environmental pollution by heat treating directly a steel wire rod then subjecting continuously the wire rod to pickling, lubricating and rust preventive treatments by a specific method. CONSTITUTION:A steel wire rod W of a high temp. emerging from a finishing mill is formed into a spiral cone C by a laying cone 2 and is subjected to regulated cooling with the warm aq. soln. 5 in a cooling water tank 4 during transfer by a conveyor 3. The rings of the coils C are then successively hooked to the hooks of a conveyor 8 so as to be vertically suspended, and while the wire rod is transferred horizontally in a horizontal transfer part 9 of the conveyor, the wire rod is dipped in the treating soln. in a surface treating tank 10 below the transfer part 9. The tank 10 consists of >=1 pieces of tanks in which >=1 kind of treatments among pickling, lubricating and rust preventive treatments are performed. The coils C subjected to such treatments are bundled with a bundling device 16.

Description

Detailed Description of the Invention (Technical Field) The present invention provides a method for directly heat-treating a hot-rolled steel wire rod in a high-temperature state through controlled cooling, and then applying surface treatment necessary for subsequent wire drawing processing, etc. The present invention relates to a method for continuously applying .

(Background Art) Various methods for direct heat treatment of steel wire rods (hereinafter simply referred to as wire rods) have been proposed in the past, such as the Stelmore method (Japanese Patent Publication No. 463 of 1973), the water or aqueous solution immersion method (Japanese Patent Publication No. 45 of 1972), -8586, Special Publication No. 46-8089), etc.

Generally, a wire rod that has been hot rolled or directly heat treated after hot rolling is once cooled to room temperature and then shipped to a wire drawing factory or a wire drawing (processing) manufacturer.

Since this coil has scale attached to its rust-preventing surface, it is pickled prior to wire drawing and subjected to lubrication treatment such as phosphate film treatment before being subjected to processing such as wire drawing.

Among these treatments, pickling has problems with waste acid and wastewater treatment, and wire drawing manufacturers tend to adopt mechanical descaling methods, but pickling cannot be discarded due to the adhesive properties of the lubricant. Because it has many advantages, it remains the mainstream for descaling.

Furthermore, conventionally, if wire rods were stored with only scale attached to the surface, they would easily rust and require extra acid to remove it, which would encourage pollution and deteriorate the surface condition.

(Disclosure of the Invention) The present invention has been made to solve the above-mentioned problems all at once. After directly heat-treating the steel wire rod, it is successively subjected to pickling treatment, lubrication treatment, rust prevention treatment, etc. using a special method. This method saves energy and resources by pickling with less scale immediately after rolling, and prevents the dispersion of pollution sources, and as a result of surface treatment, rusting during storage of wire rods is also prevented. The purpose of this invention is to provide a method for direct heat treatment and surface treatment of steel wire rods.

The present invention involves forming a hot-rolled high-temperature steel wire into a spiral coil using a loop-forming device, controlling and cooling the coil while transferring it, and subjecting it to a predetermined heat treatment. While transferring the coil in a substantially horizontal direction with the ring suspended on the hook of a hook conveyor,
A method for directing steel wire rods, which is characterized in that the steel wire rods are continuously subjected to one or more treatments selected from pickling treatment for descaling, lubrication treatment, and rust prevention treatment, and then bundled into wire rod coils. This is a heat treatment/surface treatment method.

In the present invention, the steel wire refers to carbon steel or Ni,
A wire rod that is hot-rolled from alloy steel to which a small amount of alloying elements such as Cr, V, Mo, and W are added, and is then processed into a steel wire by wire drawing or the like.

In the present invention, the predetermined heat treatment of controlling and cooling the coil while transferring the coil is performed at a high temperature of hot rolling (e.g., 800~100℃).
This method improves wire drawability by adjusting the cooling rate to cause pearlite transformation while transferring the wire at a temperature of 00°C. Near the temperature where it does not get cold (e.g. about 600°
Pre-cooling may be performed to cool the steel to C or higher), and heat treatment may be added to improve toughness by suppressing the growth of crystal grains and making them finer.

There are no particular restrictions on the method of this predetermined heat treatment, and the shape of the coil to be transferred may be, for example, a coil developed into a non-concentric horizontal ring shape with a substantially constant pitch and placed on a conveyor. The coil may be transported in the form of a vertical ring with an open pitch on a conveyor, or it may be transported with a coil ring suspended from the hook of a horizontal hook conveyor as described later. The refrigerant may be water, an aqueous solution, another liquid, a fluidized bed, a blast, or the like. In this case, it is desirable to use a method suitable for subsequent processing (surface treatment), and the transfer state should be a non-concentric horizontal ring shape, or a ring shape hung on a hook that can be easily transferred to the next hook conveyor. It is preferable to use a cooling method that produces less scale and facilitates subsequent pickling, and from this point of view, a cooling method in hot water or a hot aqueous solution is preferable to an air cooling method. .

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described by way of embodiments with reference to the drawings.

FIG. 1 is a longitudinal sectional view illustrating an embodiment of the method of the present invention. In the figure, the high-temperature steel wire W coming out of the finishing mill (not shown) is quenched as necessary, and then the pinch roller I
The coil C is formed into a helical coil C having a predetermined ring diameter by the laying cone 2, and falls naturally onto a conveyor 3 having an inclined transfer section. This conveyor 3 transports the coil CL in the form of a non-concentric horizontal ring with an approximately constant pitch. During this time, the coil C undergoes appropriate controlled cooling and changes from the high-temperature austenite structure to fine particles. It changes to a pyrite structure, improving wire drawability.

In the figure, a conveyor 3 is provided in a cooling water tank 4, and a hot water solution 5 containing, for example, a surfactant (eg, polyvinyl alcohol, etc.) is contained in the cooling water tank 4.
The upper coil C is immersed in a hot water solution 5.

Note that this heat treatment is not limited to the method shown in the figure, and may be any of the direct heat treatment methods described above.

Following the inclined conveyor 3, the coil C is transferred onto a horizontal conveyor 6. A hook conveyor 8 having hooks 7 with long arms is installed next to the horizontal conveyor 6.
The rings of coils C unfolded on the conveyor 6 are successively hooked onto the hooks 7 and suspended vertically, and as the conveyor 8 rotates, they are transferred horizontally by the horizontal transfer section 9. In this case, it is preferable to align the pitch of the horizontal rings of the coils C on the conveyor 6 during transport so that they can be easily hung on the hooks 7, which makes hanging on the hooks 7 extremely easy.

A surface treatment tank 10 is installed below the horizontal transfer section 9 of the hook conveyor 8, and the coil C below the moving hook 7 is immersed in the processing liquid in the processing tank 10.

The surface treatment tank IO carries out a selected one of pickling treatment for descaling, lubrication treatment, and rust prevention treatment. Figure 2 is a diagram showing an example in which the surface treatment tank is composed of three treatment tanks.
1 is a pickling treatment tank, 12 is a lubrication treatment tank, 13 is a rust prevention treatment tank, and coil C is a horizontal transfer section 9'.

They are sequentially immersed in these treatment tanks by a hook conveyor 14 having 9J and 9/ to undergo surface treatment.

Hydrochloric acid or sulfuric acid is used for pickling treatment, and lubrication treatment forms a lubricating film on the surface. Lime soap treatment, borax treatment, chemical conversion coating treatment such as phosphate, or a combination of these are used to prevent rust. The treatment is to prevent rusting during storage, and is coated with wax or the like. These treatments may be performed by immersion in liquid, spray treatment, or a combination thereof.

Further, a cleaning device may be provided between each type of treatment, if necessary, to provide a cleaning process.

In this manner, the coil C is suspended from the hook and each ring comes into contact with the treatment liquid in a separated state, so that uniform surface treatment is achieved over the entire surface.

It should be noted that the transfer parts 9, 9' of the hook conveyors 8, 14 may be of any type as long as they transfer the coils in a horizontal direction, that is, in a substantially horizontal or slightly inclined direction so that the coils C can be easily immersed in each processing tank.

The hooks 7 of the hook conveyors 8 and 14 may support each ring of the coil C at one point, but if they are configured to support each ring of the coil C at at least two fulcrums spaced at appropriate intervals, Rotation of the ring in the horizontal plane during suspension is prevented, and deformation of the ring shape can be suppressed.

Also, if the number of rings of the coil C to be hung on one hook 7 is within a few turns, the surface of the receiver of the hook part should be set appropriately (for example, the surface of the receiver should be in a horizontal straight line in the transfer section, If an appropriate number of grooves are provided on the surface to allow the ring to fit, the ring will separate on the surface and uniform processing will not be adversely affected.

The coil C that has undergone such surface treatment is transferred onto the inclined conveyor 15 for carrying out and carried out from the tank, and if necessary,
After being coated with something to help with lubrication and rust prevention, such as metal soap or wax, and dried, the focusing device 1 is assembled using a known method.
Focused on 6. Note that the unloading device may be of another type, and the coil may be bound after focusing, but it may also be a carrier taker.

When surface treatment is performed continuously as described above, the scale after direct heat treatment is thin and pickling is performed in a state with good pickling properties, so fewer chemicals are used and pickling is easy in a short time. In addition, since the temperature of the wire rod that undergoes surface treatment can be raised, there is no need to heat the liquid that was conventionally required for pickling treatment, lubrication treatment, etc., and there is no need to take time to heat up the wire rod itself, resulting in energy savings and savings. It is advantageous in terms of resources. In this way, pickling after heat treatment,
Wire rods that have been subjected to lubrication treatment and anti-corrosion treatment hardly develop rust during storage, have anti-rust properties, and can be directly subjected to subsequent processing, such as wire drawing.

(Example) SWRH82B steel (JIS standard product, CO, 8) 96.
Mn 0.69%) was rolled into Iommf and processed by the method of the present invention shown in Fig. 1 using the surface treatment equipment shown in Fig. 2↓
A wire coil was created by direct heat treatment and surface treatment.

The hot rolling speed was 20 m/sec, and the cooling water tank 4 used hot water at the boiling point of an aqueous solution containing 0.1% polyvinyl alcohol. A 20% HCβ solution at 60° C. was used for the pickling treatment, a phosphate film treatment was performed using a zinc phosphate treatment solution for the lubrication treatment, and wax 'f was applied as an antirust treatment. Although the time required for pickling was only about 5 seconds, a phosphate film without any problems could be obtained.

The obtained wire had an average tensile strength of 116 Kg/mrJ, and after being stored in a warehouse for 15 days, its i! As a result of drawing the wire to a diameter of 4 mm using a continuous wire drawing machine, a steel wire with a good surface texture was obtained without any problems such as on the middle side of the wire drawing.

(Effect of the invention) Direct heat treatment and
The surface treatment method has the following effects.

(a) After hot-rolled high-temperature steel wire is formed into a spiral coil using a loop forming device, and the coil is subjected to a prescribed heat treatment, the ring of the coil is subsequently suspended from a hook of a hook conveyor. While the coil is being transported in a substantially horizontal direction, the coil is suspended from a hook in order to be continuously subjected to one or more treatments selected from pickling treatment for descaling, lubrication treatment, and rust prevention treatment. The held coil comes into contact with the surface treatment liquid in the form of almost separate rings, and is treated uniformly and easily over the entire surface, so that at the same time as rolling,
It is possible to produce wire rods that have been heat-treated and lubricated, have anti-corrosion properties during storage, and can be directly subjected to subsequent processing, such as wire drawing.

(b) Since the scale is minimal immediately after the wire rod is rolled, there is no rust, and the wire rod is pickled while maintaining an appropriate temperature, fewer chemicals are used and the time is short, saving resources. It is advantageous in terms of energy saving.

(c) Since the temperature of the wire before entering pickling treatment and lubrication treatment can be matched to the temperature of the treatment liquid, there is no need to heat the treatment liquid, and energy can be saved.

2) The rolling manufacturer performs pickling and other treatments in bulk, eliminating the need for the two-step process at the wire drawing manufacturer, which prevents pollution sources from dispersing and reduces pollution.

(e) The treated wire rod hardly develops rust during storage, so the surface texture does not deteriorate and the surface quality of the steel wire is improved.

[Brief explanation of the drawing]

1 and 2 are longitudinal cross-sectional views for explaining an embodiment of the method of the present invention, respectively. FIG. 1 is a diagram showing direct heat treatment and surface treatment, and FIG. 2 is a diagram showing surface treatment. l...Pinch roller, 2. Laying cone, a,
6゜15... Conveyor, 4. Cooling water tank, 5. Hot water solution, 7-. Hook, 8.14 Hook conveyor, 9,9
'...Horizontal transfer section, 10 Surface treatment tank, 11... Pickling treatment tank, 12. Lubrication treatment tank, 13 Rust prevention treatment tank, 16
...Focusing device. Figure 1 Figure 2 No. 4

Claims (3)

[Claims] (1) Hot-rolled high-temperature steel wire is formed into a helical coil using a loop forming device, and the coil is cooled and subjected to a predetermined heat treatment while being transferred, and then the ring of the coil is transferred to a hook conveyor. While transporting the coil in a substantially horizontal direction while suspended from a hook, the coil is continuously subjected to one or more selected treatments among pickling treatment for descaling, lubrication treatment, and rust prevention treatment. A method for direct heat treatment and surface treatment of steel wire, which is characterized in that the steel wire is bundled into a wire coil after being treated. (2) The method for direct heat treatment and surface treatment of steel wire according to claim 1, wherein the lubrication treatment is lime soap treatment, borax treatment, chemical conversion coating treatment, or a combination thereof. (3) Pickling Treatment 1 Direct heat treatment/surface treatment method for steel wire according to claim 1 or 2, wherein the lubrication treatment or rust prevention treatment is performed by immersion in liquid, quick treatment, or a combination thereof. .