JPH05185238A - Welding method for clad materials - Google Patents

Abstract

PURPOSE:To satisfactorily perform welding and joining at the time of joining the clad materials by performing underlaying by the welding process with the shallow penetration and then, performing finish-laying by the welding process with the deep penetration in the welding method to multi-lay filler metal on a cladding material groove. CONSTITUTION:In joining the clad materials 1 covered with cladding materials 3 on base metals 1, the filler metal is multi-laied on the cladding material 3 groove according to this welding method. The underlaying is performed by the welding process with the shallow penetration and then, the finish-laying is performed by the welding process with the deep penetration. Consequently, the composition change of a weld zone is slight, the weld zone having the composition aimed at and few defects and having desired characteristics is formed on the cladding material groove and the clad materials are satisfactorily welded and joined together via this weld zone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for welding a clad material, in which a clad material obtained by coating a base material with a foreign material is joined by welding.

[0002]

2. Description of the Related Art Conventionally, there has been known a clad pipe in which a base material is coated with a different material for improving the function of a pipe made of a single material. When a longitudinal joint of the clad pipe is butt-joined, Since the base metal and the composite material have different compositions, generally, the base material and the composite material are welded in separate steps by using filler materials having the same or similar compositions. .. As an example,
Explaining the case of joining a clad pipe longitudinal joint coated with an alloy such as Inconel, Monel Metal, Hastelloy (all are registered trademarks) as a joining material, after the butt welding of the steel pipe base material, the joining material A filler material having a composition similar to that of an alloy is melted by a TIG welding method with a relatively shallow penetration to form a bead,
This is repeated twice or more and the beads are multi-layered and joined. Also, as another method, a method of using a submerged arc welding method in which the base metal penetration is relatively deep is known, instead of the above-mentioned TIG welding method. In this method, the base material is deeply melted depending on the depth of penetration, and the filler material, the joining material and the base material are fused at once, and welding is performed by forming a single-layer bead in one pass. ..

[0003]

However, when the beads are stacked and welded by the TIG welding method with a shallow penetration, not only is the efficiency inferior, but the composition between the bead layers is likely to vary, and further, the fusion failure is caused. However, there is a problem in that welding defects are likely to occur. On the other hand, in the case of welding by a deep-penetration submerged arc welding method, the above-mentioned problem is unlikely to occur, but the base metal is melted to a deep depth by the arc, and this is melt-mixed with the filler metal, thereby A phenomenon occurs in which the composition is affected by the composition of the base material and greatly differs from the intended composition.

In particular, when a high alloy such as the above alloy is coated as a composite material, the necessary alloy components are diluted by mixing with the base material, and the desired characteristics cannot be obtained by adding the components. However, it may impair other properties such as deterioration of corrosion resistance. Since such a welded portion is inferior in properties to the laminated material, there is a problem that the properties of the entire clad pipe are impaired. This invention has been made against the background of the above circumstances, and defects occur in the welded portion,
An object of the present invention is to provide a clad material welding method capable of joining clad materials with each other with high efficiency without diluting the components.

[0005]

In order to solve the above problems, the method for welding a clad material according to the present invention is such that when the clad materials in which the base material is coated with the clad material are joined, the clad material is welded to the groove of the clad material. This is a welding method for laminating multiple layers of additive material, characterized in that the underlaying is carried out by a shallow welding method and then the finishing welding is carried out by a deep welding method. Examples of the clad material include a clad pipe and a clad plate, and the types and components of the base material and the laminated material forming the clad material are not limited.

Although a suitable groove is formed at the abutting portion of the mating members, the shape of the groove is not limited to the present invention. Two or more layers of beads are stacked and welded to this groove. As the shallow welding method for forming the bead of the underlay, there are TIG welding method, plasma welding method,
A powder plasma welding method and the like can be exemplified, and as a deep-penetration welding method, a submerged arc welding method, M
The IG welding method and the like can be exemplified. However, since the difference in the penetration depth between these welding methods is relative, it is possible to select a shallow penetration depth and a deep penetration depth from those exemplified as the shallow penetration depth.

[0007]

In other words, according to the present invention, since the underlay is carried out by the shallow welding method, the melting of the base metal can be suppressed to the minimum necessary for fusion welding, and the underlay welding by fusion with the base metal can be performed. Reduces the effect on the composition of parts. After that, with the finishing assortment,
By applying the deep-penetration welding method, the bead of the lower layer is remelted and integrated with the finishing layer, and a uniform, bead-like bead is formed. In addition, defects such as unmelted residue generated at the time of underlaying are removed by sufficient melting, and a weld having a clean structure can be obtained. Further, at this time, the melting of the base material is prevented as much as possible, so that the composition change of the welded portion can be minimized. From this point, it is desirable to control the penetration so that it is directly below the fusion portion of the underlay welding and the base metal during the finish welding.

[0008]

EXAMPLES Examples of the present invention will be described below. A clad pipe 1 shown in FIG. 1 is configured by covering a base material 2 with a laminated material 3 made of a heat-resistant alloy. The clad pipes 1 and 1 are arranged so as to face each other. The two have already been welded together, and the groove 4 has been formed on the laminated materials 3 and 3.
Are formed. The compositions of the base material 2 and the laminated material 3 are as shown in Table 1. The first layer of overlay (lower overlay) is performed on the groove by automatic TIG welding. As the filler material, a thin wire having a diameter of 1.2 mm and having the composition shown in Table 1 was used, and welding was performed under different welding conditions as shown in Table 2 to obtain the undercoating test material No. 1-5 were obtained. The composition of each of the obtained underlay test materials was analyzed, and Ni, Cr,
The contents of Mo and Fe components are shown in Table 3.

[0009]

[Table 1]

[0010]

[Table 2]

[0011]

[Table 3]

Next, the second layer of overlay (finish overlay) was performed by submerged arc welding under the welding conditions shown in Table 4. The composition of each of the obtained finished sample materials was analyzed in the same manner as above, and the results are shown in Table 5. As is clear from this result, in all of the obtained finished embossed test materials, the composition change was small compared to the initial composition, and desired characteristics were secured. Moreover, the uniformity of the welded portion was excellent, and no welding defect was found. On the other hand, for comparison, the sample No. Comparative material 6 was obtained by performing further TIG welding on the clad material under the welding conditions shown in 2 and then further finishing finishing by TIG welding under the same welding conditions as the underlaying. When the composition analysis of the welded portion was performed, as shown in Table 5, the composition of the finished weld layer (second layer) was good, but non-uniformity of the components occurred in the first and second layers. Weld defects such as poor fusion were found in the parts.

Further, with respect to the above-mentioned clad pipe joint, submerged arc welding was performed under the welding conditions shown in Table 6 without performing TIG welding to form a single-layer bead in one pass and welding was completed. Got The results of analysis of the composition of this welded portion are shown in Table 5, and the Fe content is increased, while the Ni content is decreased, and the components are diluted. Due to this change in composition, the welded part had reduced properties such as corrosion resistance.

[0014]

[Table 4]

[0015]

[Table 5]

[0016]

[Table 6]

In the welding of the above-mentioned clad pipe, it is desirable to carry out the welding conditions shown in Table 7 when TIG welding and submerged arc welding are performed in consideration of the above results. Under these welding conditions, the melting of the base metal during TIG welding is suppressed to the necessary minimum, and it is sufficiently remelted to the first layer during submerged arc welding and the melting of the base metal is prevented. And welded to form welds without component dilution or defects. In addition, in the said Example, although the welding method using the TIG welding method and the submerged arc welding method was demonstrated, this invention is not limited to this, Other welding methods may be combined as mentioned above. It is also possible to do so.

[0018]

[Table 7]

[0019]

As described above, according to the method for welding a clad material of the present invention, a plurality of filler materials are stacked in the groove of the clad material composed of the base material and the clad material to form a clad material. It is a method of welding the undercoat by a shallow penetration welding method for the underlay, and then a final welding is performed by a deep penetration welding method, so the composition change of the welded part is small and it has the desired composition and less defects. As a result, a welded portion having desired characteristics is formed in the groove of the laminated material, and the clad materials are satisfactorily welded and joined to each other via the welded portion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a joined state of a clad pipe in an example.

[Explanation of symbols]

 1 Clad pipe 2 Base material 3 Laminated material

Claims (1)

[Claims] 1. A welding method of laminating multiple layers of filler material in the groove of the laminated material when joining the clad materials coated with the laminated material to the base material, wherein the underlay is a shallow welding method. Welding method for clad materials, characterized in that the welding is performed after that, and then the finishing weld is performed by a deep-penetration welding method.