JPS61279334A - Flash butt welding method for large diameter chain - Google Patents

Abstract

PURPOSE:To improve the reliability of a product by forming parallel planes on a base material by a specified compression ratio, and subsequently, clamping its parallel planes by an electrode, and executing the welding. CONSTITUTION:In the electrode contact part of a base material 1 having a circular section, parallel planes 3, 3 are formed in advance through rolling for forging by the compression ratio of 10-30% of the diameter. Subsequently, these parallel planes 3, 3 are clamped by electrodes 2, 2, and a flash butt welding is executed. According to this welding method, the generation of a die burn, which is caused by the generation of a spark between the electrode 2 and the base material 1 is prevented completely. Accordingly, a trouble for repairing a product chain becomes unnecessary, and the reliability of a product is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a flash butt welding method, particularly a 7-latch unit welding method for large-diameter chains with excellent welding workability.

(Prior Art and Problems) In general, large-diameter chains are known as K-type chains, as seen in, for example, "Steel Research" No. 314 (1984), page 72.

It is manufactured through the steps shown in FIG. As you can see in the same figure, K,
The conventional manufacturing process for large-diameter chains is to use round steel as a raw material, saw it into a predetermined length, and heat it to make it easier to bend.
Bend it into a 0-shape, and while the material is still hot, weld the butt parts together with a 7-latch set.

In most cases, this conventional 7-lattice welding method for large-diameter chains uses flat electrodes 2 arranged vertically to bend them into a 0-shape, as shown in the perspective view of Figure 3 (A). This is done by clamping the processed material l near the abutting part.

However, in this case, the material 1, whose cross-sectional shape is close to a circle, is clamped by the flat electrode 2, so the material 1 and the electrode 2 are in line contact, as shown in the cross-sectional view of FIG. 3(B). It will be close. During welding, a high current of tens of thousands of amperes or more flows through the welding process, which causes snog to occur between the material and the electrode, causing flaws called dynos in the chain links. These flaws are checked and repaired in the flaw inspection process shown in FIG. 2, but this not only takes a lot of man-hours, but also may degrade the performance of the large diameter chain.

Therefore, the occurrence of diburn has been a major problem in the manufacture of large diameter chains.

(Means for Solving the Problems 5) The present invention provides 7:) of a large-diameter chain: When welding a large-diameter chain, the diameter of the material is After compressing and deforming the material at a compression ratio of 10 to 30% to form parallel surfaces at least at the portions of the material that are in contact with the electrode during welding, the parallel surfaces are formed! This is a flash knot welding method for large-diameter chains that is characterized by welding by clamping at poles.

As a result of various studies to solve the above-mentioned problem, the present inventors found that in the prior art, the material 1 and the electrode 2 are in line contact as shown in FIG. Considering that this is likely to occur, make sure that there is surface contact between the material and the electrode.
By compressing the material to be welded in advance from the direction in which it contacts the electrode, a flat cross section is formed, and the resulting parallel surfaces are clamped with an electrode to perform flash butt welding. The present invention was based on the discovery that the large-diameter chain thus obtained has almost no problem in terms of interloading properties and is comparable to conventional chains.

Below, the present invention will be described in detail.

First, in the present invention, the materials to be welded are JIS round steel for chains, 5BO50, 5BO70, and 80M420.
Round steel with a diameter of 30 mmφ to 200 mmφ made of mechanical structure materials such as SN0M430, or a material that has been cut to a predetermined size and bent into a desired shape such as a 0-shape. This refers to materials used as link materials for large-diameter chains.

In the present invention, the material is compressively deformed from the direction in which it contacts the electrode at a compression ratio of 10 to 30% to form a bottom shape on the surface parallel to the material. Generally, a rolling mill or a forging machine can be used. In particular, when compression deformation is performed before bending, it is more efficient to use a rolling machine, and when compression deformation is performed after bending into a 0-shape, it is more efficient to use a forging machine.

Here, the lower limit of the compression ratio was set at 10% because the effect of preventing the occurrence of diverging is insufficient if it is less than 10%, so the upper limit was set at 30%.
% because if it exceeds this, the link will become flat and the bending rigidity of the link will drop significantly.Also, the link shape is conventional, e.g. j is normal as specified in JIs F3303. This is because the link is significantly different from the link, and conventional chain accessories cannot be used, and the chain cannot be handled in the same way as a conventional chain.

In addition, in the case of compression deformation before bending, after compression deformation, it is bent into a 0-shape according to the conventional process, but in any case, the bent material is The butt portions are flash butt welded in the same manner as the conventional means shown in the figure. However, when performing flash butt welding, the electrode is brought into contact with the parallel portion as shown in FIG.

That is, FIG. 1 is a perspective view (FIG. 1 (A)) and a cross-sectional view (FIG. 1 (B)) showing an embodiment of the flash/shot welding method for large diameter chains according to the present invention. ,
As shown in the figure, electrodes 2, 2 are brought into contact with parallel surfaces 3.3 provided on the upper and lower surfaces of the material 1, and flash butt welding is performed using a clamp mechanism or a welding power source (not shown).

Regarding the formation of the parallel surfaces 3, 3, especially in the case of KEE shrinkage deformation before bending, it is not always necessary to have parallel surfaces continuously over the entire length of the material, but it is necessary to form parallel surfaces at the locations where the electrodes come into contact during welding. As long as it is formed, there is no problem even if it is intermittent.

Hereinafter, the effects of the present invention will be described in more detail with reference to Examples.

(Example) When manufacturing a large diameter chain of 27.5 m consisting of 89 links using 5BO70 of 78 mm x 1 φ, the chain was manufactured in the process shown in Fig. 2 according to the procedure shown in Fig. 3 as before. For the other series, 5BO70 with a diameter of 78 mm 4φ was subjected to compression deformation with a compression ratio of 14% by hot rolling to form parallel surfaces, and the cross-sectional shape was as shown in Figure 1 (B). The conditions were the same as those shown in FIG. 2 above.

In addition, the capacity of the flash knot welding machine is 1500
kVA is used, and the welding conditions are voltage 10V.

It has a 15mm flash, a 60mm twist, and an upset force of 40 tons.

As a result of examining all the chain links for the presence or absence of dynos, it was found that there were no dynos in the chain links manufactured by the method of the present invention, whereas those manufactured by the conventional method did not have any diburns in the J links. It was seen. These chains fully satisfied the mechanical properties required for JI8 type 3 chains, and the chains produced by the method of the present invention did not have any problems.

(Effects of the Invention) As described above, according to the method of the present invention, no dyno knots occur during flash knot welding of large diameter chains, and
Therefore, a chain with high reliability is obtained instead of a frame that requires no repair work, and the industrial effect is truly remarkable.

[Brief explanation of drawings]

Fig. 1 is a perspective view (fA in the same figure) and a cross-sectional view (Fig. FIG. 3 is a schematic diagram showing the manufacturing process of a chain, and FIG. 3 is a perspective view (FIG. 3(A)) and a cross-sectional view (FIG. B)]. l...Material, 2...Electrode, 3...Parallel surface. Agent Patent attorney Masa Akizawa Mitsunobu 2 people 7I'''1 Figure 7t'z Figure - Ward Jit]= Row Ward 1

Claims (1)

[Claims] (1) When flash butt welding a large diameter chain, compressive deformation is applied from the direction corresponding to the side where the electrode contacts the material to be welded at a compression ratio of 10 to 30% of the diameter of the material to at least weld the material. A flash butt welding method for large diameter chains, which is characterized in that parallel surfaces are formed at locations where electrodes come into contact, and then the parallel surfaces are clamped with electrodes to perform welding.