JPS6056498A - Production of flux cored wire - Google Patents

Abstract

PURPOSE:To improve remarkably drawability by forming a slit hoop steel to a hoop of a trapezoidal sectional shape having a uniform thickness within the specified tolerance and smooth sloped edges on both sides then supplying a flux to the inside surface side while forming the hoop to a tubular body. CONSTITUTION:A hoop steel 3 is passed through the 1st vertical rolling part 5 and is plastically worked to a hoop steel 3X, by which both end faces of the hoop 3 are formed to a smoothly curved shape. The hoop 3X is then passed through the 1st horizontal rolling part 6 to form a hoop 3Y, by which about 45 deg. tapered surface is formed in the upper part of both end faces. The hoop is thereafter passed through the 2nd vertical rolling part 7 to form a hoop 3Z, by which the uniform thickness within the specified tolerance is provided thereto, and about 25 deg. tapered surface is formed to both end faces. Such hoop 3Z is fed to a wire drawing stage II where the hoop is formed to a tubular body and a flux is supplied to the inside surface side so as to be enclosed and filled in the tubular body. The tubular body is then drawn to a prescribed size by a drawing machine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention efficiently produces high-quality flux-cored wire by drawing the outer shell wire in a state where the joints in the circumferential direction are in sufficient contact with each other before the wire drawing process. It relates to a method by which it can be manufactured.

Flux shear wire has a structure that is made by filling a hollow tube made of rolled steel strip with flux, and the most common manufacturing method is as shown in Figure 1 (process explanation diagram). be. That is, a wide steel strip 1 with a clean surface is slit in the slitting process section 2 to form a slit steel strip 3 of a predetermined width, and while the steel strip 3 is sequentially bent into a U-shape, a flux 4 is applied inside it. In this method, a slit steel strip (hereinafter simply referred to as steel strip) 3 is formed into a circular shape while aligning both side edges 3a and 3b, and then wire-drawn to a predetermined size. In addition, during wire drawing, lubricants are generally used to improve wire drawability, but the forced lubrication method described below is particularly effective for further improving wire drawability, so we recommend using it. is desired. The forced lubrication method involves applying a large amount of solid lubricant to the surface of the roller, and pressing this application roller onto the surface of the flux-cored wire in the initial stage of wire drawing using a spring, etc. to provide lubrication and improve wire drawability. However, in the conventional flux shear wire manufacturing method, it is difficult to apply this forced lubrication method for the following reasons. That is, FIG. 2 is an enlarged cross-sectional view of the steel strip 3, and as shown in the figure, there is a so-called ridge portion B at the upper part of both side edges 3a+3b.

B' is occurring. Therefore, when the steel strip 3 is rolled in the width direction and formed into a circle, the seam in the circumferential direction is shown in Fig. 3 (tAI
As shown in the enlarged view of fT plane), sufficient adhesion cannot be obtained due to the contact between the button ridges B and B'. If forced lubrication is performed under these conditions, the solid lubricant will enter a portion of the core, changing the wire composition and eventually the weld metal composition. Also, not only solid lubricants but also general wire drawing lubricants, depending on the type, the above composition changes may occur due to intrusion.
The scope of application of general wire drawing lubricants is severely limited.

Furthermore, leakage from a part of the core to the outside occurs, and in this case, flux gets mixed into the lubricant, resulting in deterioration of lubrication performance. Therefore, so-called die roughness is likely to occur,
Problems such as wire breakage are also more likely to occur. Also, with solid lubricant or flux embedded in the joints of the steel strip 3,
The surface of a product wire that has been subjected to a wire drawing process is not smooth and tends to impair the stability of wire feeding during welding work.

Under such circumstances, the present inventors have made it possible to apply the above-mentioned forced lubrication method to improve wire drawability and to obtain a product wire with good surface quality. The guideline was that we should develop a means to bring the seams into sufficient contact with each other, and we have been conducting intensive research to develop such a means.

By the way, in order to achieve such adhesion, it is thought that it is effective to smooth both edges of the steel strip, but if this processing is done with scarf ink (bit cutting), the cutting oil will be 7 lacs. It was not adopted due to remaining problems such as: (1) difficulty in processing chips; (2) poor material yield.

The present invention was completed through such research, and has a trapezoidal cross section that has a uniform thickness within specified tolerances and smooth sloped side edges by subjecting a steel band to one or more stages of rolling in advance. The gist of this method is that after the steel strip is formed into a shaped steel strip, it is formed into a tubular body with both side edges of the steel strip in close contact with each other and then subjected to a wire drawing process.

The configuration and effects of the present invention will be explained below with reference to the drawings. The most distinctive feature of the structure of the present invention is the above-mentioned through-cut and smooth processing of both edges of the steel strip (hereinafter referred to as end-face processing). First, the specific structure of the end-face processing will be mainly explained. . Fig. 4 is a process explanatory diagram of the method of the present invention, showing that the steel strip 3 is sequentially passed through an end face processing process and a wire drawing process to obtain a product of predetermined dimensions. There is. In end face machining process I, 5 is the first
Vertical rolling section, 6 is the first horizontal rolling section, 7 is the second vertical rolling section, and 6 rolling section 5゜6.70 The shaded areas in the figure are each rolling section 5, 6゜7. This figure shows the cross-sectional shape of a caliber four wheel used in a rolling mill. Band steel 3
The steel strip BX is first passed through the first vertical rolling section 5.
The steel strip 3 has a smooth curved surface on both end surfaces.

Next, this steel strip 3X is passed through the first horizontal rolling section 6 to be plastically worked into a steel strip 3Y, thereby forming tapered surfaces of about 45° on the upper portions of both end faces of the steel strip 3X. Next, this steel strip 3Y
The steel strip 3Z is plastically worked by passing it through the second vertical rolling section 7, giving it a uniform thickness within specified tolerances (i.e., thickening) and tapering the entire end surface by about 25 degrees. form a surface.

The steel strip 3Z whose end face has been processed in this manner is then supplied to the wire drawing process (2), where it is subjected to the wire drawing process (see FIG. 1) in the same manner as in the prior art. That is, a steel strip 3 having a trapezoidal cross section is curved into a U-shape, and 7 sixes are placed inside the steel strip 3.
The 7-lux internal tubular body, which has been formed into a circular shape while aligning both inclined side edges of z, has a structure shown in FIG. 5 (enlarged cross-sectional view). That is, at the seam in the circumferential direction of the steel strip 3Z, about 60 to 80% of the thickness of the steel strip 3Z is pre-metallized.
It is in close contact. Therefore, forced lubrication using a large amount of solid lubricant can be performed on such a flux-containing tubular body at a relatively early stage of the subsequent die wire drawing, so that the wire drawability can be greatly improved. In addition, it is possible to completely prevent lubricant from entering the core portion and leakage of flux to the outside, resulting in a product wire with a smooth surface and ensuring stability during wire feeding.

It should be noted that the above embodiment is merely a representative example and does not limit the present invention, and it is possible to implement the invention by appropriately changing the design within the scope of the above-mentioned spirit. be. For example, in the above embodiment, the end face machining process was configured with three rolling stages, but it can be configured with two stages, one stage, or four or more stages depending on the plastic deformation ability of the steel strip. The hole shape of the caliber roll can be designed using the following steps. Furthermore, regarding the rolling method, both cold and hot rolling methods are applicable.

Since the present invention is configured as described above, it is possible to enjoy the unique effects summarized below.

(1) Forced lubrication method can be applied at the initial stage of wire drawing, and the range of application of general wire drawing lubricants is expanded, so wire drawability can be significantly improved.

(2) Since there is no fear that the lubricant will enter a part of the core, no change is observed in the flux components, and a product wire of a predetermined quality can be obtained.

(3) Since there is no so-called fusic leakage, it is possible to eliminate die roughness and disconnection accidents caused by lubricant contamination.

(4) Since the surface of the product wire is smooth, there is no risk of compromising stability during wire feeding.

[Brief explanation of drawings]

Figure 1 is a process explanatory diagram showing the conventional 7-lux shear wire manufacturing method, Figures 2 and 3 are enlarged cross-sectional views a-a and b-b of Figure 1, respectively, FIG. 5 is a process explanatory diagram illustrating the method of manufacturing a shear wire with a fusic according to the invention, and FIG. 5 is a diagram corresponding to FIG. 3 in the manufacturing method of the present invention. 1... Wide band steel 2... Slitting process section 3.3X,
3Y, 3Z... Slit steel strip 4... Flux 5... First vertical rolling section 6... First horizontal rolling section 7... Second vertical rolling section Fig. 1 Fig. 3 Figure 4

Claims (1)

[Claims] The slit steel strip obtained by slitting a wide steel strip into a predetermined width is rolled in the width direction to form a tubular shape, and 7 lux is supplied to the inner surface to fill the tubular body, and then by a wire drawing machine. In a method for manufacturing slack shear wire in which wire is drawn to predetermined dimensions, the slit steel strip is rolled in one or more stages in advance to form a trapezoidal cross-sectional shape having a uniform thickness within specified tolerances and smooth inner inclined side edges. After forming the steel strip,
A method for producing a flux-cored wire, comprising forming the tubular body.