JPH02235577A - Welding method for stainless clad steel plate - Google Patents

Abstract

PURPOSE:To obtain the satisfactory welding quality and a weld zone having corrosion resistance by using welding materials where the corrosion resistance equal to the cladding materials of clad steel plates is obtained and melting up to base metals by one pass from the surfaces of cladding materials to perform welding. CONSTITUTION:The two stainless clad steel plates 11 consisting of carbon steel base metals 12 and stainless steel cladding materials 13 are combined in a Tee joint and a corner part at the cladding material 13 sides is subjected to fillet welding. At this time, melting is carried out up to the carbon steel base metals 12 by one pass welding by the shielded metal arc welding method, consumable electrode gas shielded arc welding method, etc., by using the welding materials where the corrosion resistance equal to the cladding material 13 is obtained in a state with the cladding materials 13 not peeled off. A weld bead 16 is formed by this deep penetration welding. By this method, the need for peeling work of the cladding materials 13 is eliminated. Further, welding without an uncertain factor with respect to the peel strength of the cladding interface is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for welding a T-joint in a welded structure using stainless steel plates. [Prior art] Figures 2 and 3 show conventional examples of the cross-sectional shape of T-joints made by fillet welding of stainless clad steel plates with a mating material thickness of about 2 to 31 cm, which are used as tank materials for chemical tankers and the like. As shown in the cross-sectional view, the former is a joint shape that is adopted for strength-important parts where relatively large stress acts on the weld, and the latter is a joint shape that is adopted for strong parts where the stress that acts on the weld is relatively small. This is a joint shape that is used in areas that are not considered important.

First, in FIG. 2, 21 is the carbon steel base material 22.
and a stainless steel plate made of a stainless steel laminated material 23 with a thickness of 2 to 3 times, 24 a weld bead in which the base metals 22 are welded together with a welding material for carbon steel, 2
5 is a weld bead in which the base materials 22 and the joining materials 23 are welded together using a welding material for dissimilar materials, and 26 is a weld bead in which the joining materials 23 are welded together using a welding material for stainless steel. Welding of such a joint shape is adopted in order to obtain joint strength that compensates for the lack of stability in the interfacial peel strength between the base metal 22 and the laminated material 23, and the stainless steel laminated material 23 is peeled off. After forming a groove in which the carbon steel base metal 22 appears, first weld the carbon steel base metals 22 together using a special welding rod or wire, and then welding the welding rod or wire for dissimilar metal welding of carbon steel and stainless steel. Welding is performed using a wire, and then welding is performed using a stainless steel welding rod or wire, and weld beads 24, 25, and 26 of three different chemical composition systems are laminated, so that the carbon steel base is welded. When welding the stainless steel mating materials 22 together, the stainless steel mating materials 23 are not melted, and when welding the stainless steel mating materials 23 together,
Welding conditions and welding methods that do not melt the carbon steel base material 22 and the carbon steel weld bead 24 are adopted.

Next, in FIG. 3, the stainless clad steel 31 is composed of a carbon steel base material 32 and a stainless steel laminated material 33, and 36 is a weld bead in which the laminated material 33 is welded with a stainless steel welding rod or wire. In this joint shape, the stainless steel mating material 33 is welded without being stripped, and the welding conditions and welding method are such that the carbon steel base material 32 is not melted. However, this type of welding method has the following problems. First of all, the thickness of the laminated material in stainless steel clad steel plates, which are normally used as tank materials for chemical tankers, is about 3.5 mm, so the groove area is narrow, and therefore, as shown in Figure 2, carbon Extremely sophisticated welding skills are required to ideally laminate different 3M weld beads of steel, intermediate dissimilar metals, and stainless steel, and in particular, covered arc welding or consumable electrode gas shielded arc welding requires rod or Since the amount of wire melted is determined by the welding current used, it cannot be controlled arbitrarily, and it is extremely difficult to stack different weld beads. Therefore, it is difficult to obtain a welded part with sufficient weld quality and corrosion resistance. Have difficulty. The second problem is the difficulty of stripping off the laminated material shown in FIG. In other words, stripping of the laminated material is generally carried out using mechanical tools, but stripping only the thickness of the laminated material requires a lot of work time, especially on curved parts such as corrugated transbulk hesodes on chemical tankers. It takes an extremely large amount of labor to strip off the part that contains the laminate, and since there are usually multiple vertical boards, the stripping work must be carried out precisely according to the spacing between them. This requires many man-hours and significantly reduces work efficiency. Furthermore, with the welding method without stripping as shown in Figure 3, there are concerns about the peel strength at the interface between the base material and the composite material, which limits its applicability. [Problem to be solved by the invention] The present invention has been proposed in view of the above circumstances.
It is possible to obtain a welded part with sufficient welding quality and corrosion resistance in a T-joint of a stainless clad steel plate, and there is no need to strip off the mating material, which saves a great deal of labor and time, resulting in a significant reduction in welding costs. A further object of the present invention is to provide a method for welding stainless clad steel slopes that eliminates concerns about peel strength at the clad interface.

[Means to solve the problem]

To this end, the present invention provides a stainless steel clad steel sheet made of a carbon steel base material and a stainless steel laminated material. When performing fillet welding from the side of the above-mentioned laminate, use a welding material that provides corrosion resistance between the laminate and the above-mentioned laminate, and without stripping the laminate, perform fillet welding from the surface of the laminate to the base metal in one pass. It is characterized by melting and welding.

[Effect]

In the welding method of the present invention, a welding material that does not cause weld defects such as weld cracks even when diluted with the carbon steel base material and has corrosion resistance equivalent to that of the laminated material is used, and penetration by welding is reduced. Adopt a penetration welding method that is thicker than the thickness of the laminated material, and weld the stainless steel laminated material so that it melts to the base metal in one bus without stripping it.

〔Example〕

An embodiment of the method for welding stainless clad steel plates according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the shape of a joint and the resulting weld bead when the method according to the present invention is carried out.

In FIG. 1, 11 is a stainless steel plate which is a material to be welded, and is composed of a carbon steel base material 12 and a stainless steel mating material 13 having a thickness of 2 to 3 liters. When combining two stainless steel clad steel plates 11 into a T-joint and fillet welding the corners of the stainless steel mating material 13111, the stainless steel mating material 13 is equivalent to the stainless steel mating material 13 without peeling off the stainless steel mating material 13. Using a welding material that provides corrosion resistance of
form.

A specific experimental example will be explained below.

SUS316L stainless clad steel or SUS is the most commonly used tank material for chemical tankers.
Gas-shielded 1.6 l diameter high Ni alloy system: 65Ni-L5Cr-15Mo-5Fe system welding wire for a T-joint made of 317L stainless steel plate with a thickness of 3. By arc welding, welding current is 450-480A and welding speed is 45-50 cm.
/sin welding conditions. As a result, a deep penetration of five or more fins was obtained in the plate thickness direction, and therefore, even if welded directly over the composite material without stripping the composite material, it was possible to sufficiently melt the carbon steel of the base material.

In addition, in this case, the maximum dilution rate of carbon steel that the weld bead received was about 30%, but when high Ni alloy wire is used, even if carbon steel is diluted to this extent, various properties of the weld metal, especially corrosion resistance, can be improved. No deterioration was observed, and it was confirmed that corrosion resistance equivalent to that of laminated materials was obtained, and there were no problems in practical use.

〔Effect of the invention〕

In short, according to the present invention, when fillet welding a T-joint of a stainless steel plate made of a carbon steel base material and a stainless steel laminate from the laminate side, a welding material that can provide corrosion resistance equivalent to that of the laminate is used. By melting and welding from the surface of the mating material to the base metal in one pass without stripping the mating material, a welded part with sufficient weld quality and corrosion resistance for a T-joint of a stainless clad steel plate can be obtained. The advantage of stainless clad steel sheets is that there is no need to strip off the laminated material, which saves a lot of labor and time, resulting in a significant reduction in welding costs.Furthermore, it eliminates concerns about peel strength at the cranoid interface. The present invention is industrially extremely useful because it provides a concubine method.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the shape of a joint in an embodiment of the method for welding stainless steel clad Svi plates according to the present invention. FIGS. 2 and 3 are cross-sectional views showing joint shapes in conventional welding methods, respectively. 11... Crafted steel plate, 12... Carbon steel base material, 13
...Stainless steel laminating material, 16...Weld bead. Agent Patent Attorney Masa Tsukamoto Letter No./Figure 3 Figure 3f

Claims (1)

[Claims] When fillet welding a T-joint of stainless clad steel plates made of a carbon steel base material and a stainless steel laminate from the laminate side, using a welding material that provides corrosion resistance equivalent to that of the laminate, A method for welding stainless clad steel plates, characterized by melting and welding from the surface of the laminated material to the base metal in one pass without stripping the laminated material.