JPS5874297A - Welding method for clad steel material - Google Patents

Abstract

PURPOSE:To eliminate the need for back chipping and to weld clad steel materials in a reduced work period by packing a backing material having plasticity in the groove on a caldding material side and welding the base metal side thereby forming penetration beads in the weld metal on the base metal side. CONSTITUTION:A clad steel material 1 wherein a cladding material 3 of stainless steel or the like is lined on a base metal 2 of mild steel or the like is welded as follows: Grooves 4, 5 are provided on both sides of the base metal 2 side and cladding material 3 side in the joined part of the material 1. A backing material 8 having plasticity is packed in the groove 5 on the material 3 side and a self-adhesive tape 9 is adhered to the material 3. Thereafter, the materials are welded from the metal 2 side to form sound penetration beads 10 on the rear surface of the weld metal 6 on the metal 2 side. The material 1 is turned over, the material 8 is removed and finally the material 3 side is welded. Since a welding method of producing beads 10 without back chipping is employed in this way, the quantity of the weld metal 7 on the material 3 side is less required and the quantity of generally costly welding materials on the cladding material side is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for welding clad steel materials, and in particular to a method for welding clad steel materials, which greatly simplifies welding work, prevents weld cracking and embrittlement, and stabilizes weld quality. Concerning the method of welding sake.

In general, clad steel is made by laminating a base material made of mild steel with a laminated material such as stainless steel, niraflu, or cupronickel that has corrosion resistance. It has been widely adopted in a wide range of fields such as

Figure 1 (I) shows the conventional welding method for clad steel materials.

The explanation will be based on (n), (1), and (IV), and the problems thereof will also be described below. Figures 1 (1) to (I
In V), 1 is a clad steel material in which a base material 2 made of mild steel is laminated with a laminate material 3 having corrosion resistance such as stainless steel.

First, as shown in FIG. 1(1), a groove 4 is provided on the base metal side of the joint of the clad steel material 1. Next, as shown in FIG. 1 (It), the base metal 2 side is welded with mild steel welding material. As shown by the broken line in the figure, if the penetration of the initial layer is deep, there is a risk that the cladding material 3 will melt into the weld metal 6 on the base metal 2 side. welding metal 6
When the mating material 3 melts, cracks or embrittlement occur in the weld metal 6. Therefore, the range of appropriate conditions for welding the base metal 2 side of the welded steel material 1 is narrow, resulting in poor stability. Difficult to apply high heat input welding such as chipping and submerged welding.

In this welding on the base metal 2 side, the penetration of the first layer portion 6a of the weld metal 6 is made shallow to prevent the cladding material 3 from melting. Next, attach the back side from the mating pillar side.

The back side is removed by, for example, digging a groove with arc air gouging and then grinding the surface with a grinder, and the side of the laminate material 3 is removed as shown in Figure 1 (1). . This back-hatching requires a lot of man-hours, takes a long time, and also causes dust scattering, resulting in a deterioration of the working environment. Also, the depth k of the backing is usually the thickness of the laminated material! . In this case, the welding is performed up to ≧AC+4 (■), and the amount of welding on the mating column side increases.

Finally, welding is performed on the laminate 3 side as shown in FIG. 1 (mV). However, since there is a large amount of hanging on the back side of the above,
This increases the amount of expensive welding material used on the side, resulting in an increase in costs. In addition, if the material of the mating material 3 has a lower strength than the mild steel of the base material 2 (for example, pure copper, cupronickel, etc.), weld metal 7 made of the same material as the mating material 3 has a depth of 1
Since the ratio of the two plate thicknesses of the base metal and the base metal becomes large, the strength of the joint decreases and the specified strength of the base metal may not be obtained.

The present invention was devised to effectively solve the problems in the conventional welding methods described above, and an object of the present invention is to fill the groove on the side of the mating column with a backing material having plasticity. By performing welding on the base metal side, a back wave bead can be formed in the weld metal on the base metal side, eliminating the need for a comb on the back side, shortening the construction period, and allowing the laminate to form within the weld metal on the base metal side. It is an object of the present invention to provide a welding method for rad steel materials that does not melt, can prevent weld cracking and embrittlement, and can also be applied to high heat input welding.

A specific example of the method of the present invention will be described in detail below with reference to FIG.

In FIGS. 2(,) to (e), reference numeral 1 is a clad steel material in which a base material 2 made of mild steel or the like is laminated with a mating material such as stainless steel or cupronickel having corrosion resistance.

First, as shown in FIG.
, 5 are provided. Here, in order to obtain a healthy Uranami bead, the groove depth should be adjusted to the thickness of the laminate plate! . Then, it
>i, + 1.0 (III) must be satisfied. Of course, other groove shapes can be varied depending on the welding method used.

Next, as shown in FIG. 2(b), a highly plastic backing material 8 is filled into the groove 5 on the side of the laminate 3. The backing material 8 is a clay-like material having heat resistance and can be easily pushed into the groove 5. Adhesive tape 9 is then applied to the lining material 3 to prevent the backing material 8 inside the groove 5 from coming off.

Thereafter, welding is performed from the base metal 2- side as shown in FIG. 2(c). By filling the groove 5 on the side of the mating material 3 with the backing material 8, a healthy underwave bead 10 is formed on the back surface of the weld metal 6 on the base material 2 side. - Because of this, there is no need for back-polishing work, which can significantly shorten the work time.

Also, due to the presence of the backing material 8, welding on the base material 2 side, welding metal 6
□The material 3 will not melt and the weld metal 6
? Cracking and embrittlement can be prevented, and high heat input welding such as submerged welding can also be applied.

Next, the clad steel material 1 is turned over and the backing material 8 is removed (see FIG. 2(d)), and finally, as shown in FIG. 2(e),
Weld the cladding material 3 side. In this way, since the welding method is used to expose the Uranami bead 10 without combing the Ura side,
The amount of weld metal 7 on the laminate 3 side>E can be reduced, and the cost of welding materials on the laminate side, which is generally expensive, can be reduced.

As is clear from the above explanation, the present invention can exhibit the following excellent effects.

<n) Fill the groove on the mating column side with backing material,
Since the base metal side is welded, a bead can be formed on the back side of the weld metal on the base metal side, eliminating the need for back patching work, simplifying welding work and shortening work time. .

(2) Due to the blocking and insulating effect of the backing material, the cladding material does not melt into the weld metal on the base metal side, which prevents cracking and embrittlement of the weld metal, making it possible to perform high heat input welding. It is also possible to apply welding methods such as submerge and MIG.

(3) Since the amount of weld metal on the mating column side is small, the cost of expensive welding materials on the mating material side can be reduced, and the corrosion resistance and strength of the welded joints are also good.

[Brief explanation of drawings]

Figure 1 (I), (n), (III), (■
) is a schematic cross-sectional view showing each process of the conventional welding method,
Figure (a) f (b) #(c) , 6) , (e
) is a schematic cross-sectional view showing each step of an embodiment of the method for welding clad steel materials according to the present invention. In the figure, 1 is clad steel material, 2 is base material, 3 is laminated material, 4,
5 is the groove, 6 is the weld metal on the base metal side, 8 is the backing material, 10
is the Uranami bead, and T is the weld metal on the mating column side. Patent Applicant Ishikawajima-Harima Heavy Industries Co., Ltd. Representative Patent Attorney Nobuo Kinutani Figure 1 Figure 2 ([

Claims (1)

[Claims] In the method of welding and joining clad steel materials, grooves are formed on both sides of the base metal side and the mating column side at the joint of the clad steel materials, and a plastic backing material is filled in the groove on the mating column side. , after welding is performed from the base metal side, a back wave bead is formed on the back side of the weld metal on the base metal side, and the backing material is removed.
A method for welding clad steel materials, characterized by welding the mating column side.