JPS6027475A - Method for welding to assure high toughness without annealing - Google Patents

Abstract

PURPOSE:To enable welding of a joint having high toughness without annealing by a simple method by installing a backing strap to the weld ends atop base metals, subjecting successively the base metals to build-up welding, tempering successively the beads of the previous layers and machining away the final bead layer and the backing strap. CONSTITUTION:A backing strap 6 of the same material as base materials 1 is installed to the weld ends in welding the weld ends atop the base materials. End beads 3 are successively built up and welded upward along the strap 6. The beads 3 are placed up to the top surface of the plate 6. The beads 3 are machined and removed down to the surface of the materials 1 upon ending of welding, by which the joint is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved welding method for ensuring high toughness without annealing of steel materials.

When welding steel materials, a method to ensure the toughness of the weld zone including the heat-affected zone, bond zone, and weld metal without annealing is to temper the previous layer bead one after another with the next layer bead to obtain a good joint. It has been known. In this method, if the bead height is high, the tempering effect will be insufficient, so the bead is often removed if necessary. However, even with such construction, as shown in Figure 1, there is a tempering failure area at the welded end of the upper surface of the base metal, including the base metal.
As shown in FIG. 2, the position of the next layer bead is brought close to the end bead and controlled with high precision, and the welded metal, bond part, and heat affected zone of the end bead are tempered.

However, it is difficult to control the position of the steel, and if an insufficiently tempered area is formed, it has the disadvantage of causing serious problems for use without annealing.

1 and 2, 1 is a base material, 2 is a welded metal placed in multiple layers, 5 is an edge weld bead on the upper surface of the base material, 4 is a next layer bead placed adjacent to the end bead 3, 5 is the heat affected area (tempering area) of the next layer bead 4. Oka, Figure 1 shows that because the end bead 3 and the next layer bead 4 are separated, some of the welded metal, bond part, and heat affected zone of the end bead 3 remain without being tempered. .

Further, FIG. 2 shows that the end bead 3 and the next layer bead 4 are sufficiently close to each other, so that the weld metal, bonding portion, and heat affected zone of the end bead 3 are sufficiently tempered. Incidentally, although not shown in FIGS. 1 and 2, it goes without saying that after additional bead welding is performed, the excess portion is removed to form a joint.

As mentioned above, in the welding method for ensuring high toughness without annealing of steel materials, the previous layer bead is tempered one after another with the next layer bead,
The method of obtaining a good joint is a well-known technique, but in the present invention, in welding the welding end of the top surface of the base material, where the position of the next layer bead must be controlled with high precision,
A patch plate is installed at the relevant part, and the welding process is extremely simple, resulting in a good joint.

That is, an object of the present invention is to weld a steel material without annealing to ensure high toughness, when welding the welding end of the upper surface of the base material, install a patch plate at the welding end of the upper surface of the base material, and sequentially perform lamination welding to weld the previous layer. To provide a welding method that ensures high toughness without annealing, which is characterized by tempering the bead and finally removing the final bead layer and the corresponding plate.

The present invention can be widely applied to welding of chemical machines, prime movers, iron-making machines, etc.

Next, the joint type of the high toughness ensuring welding method without annealing of the present invention,
The construction procedure will be explained with reference to FIGS. 3 and 4.

In Figures 3 and 4, (a) is butt welding, (
B) shows the case of overlay welding. Symbols 1 to 5 in the figure are the same as those in Figures 1 and 2, and 6 is a caul plate that is attached to the outer surface of the groove and is made of the same material as the base material in principle, and 7 is the caul plate 6. This is a tack welding part where the base material 1 is tacked.

FIG. 4 shows a welding procedure according to the present invention, which is characterized in that the end beads 3 are sequentially stacked and welded upward over the backing plate 6. Then, the weld bead is placed up to the upper surface of the backing plate 6, and after welding is completed, the bead is removed to the surface of the base material 1 to complete the joint.

According to the welding method of the present invention, the following effects are brought about.

(1) In the conventional method, in order to reliably obtain the tempering effect at the welded end of the upper surface of the base metal, it is necessary to place adjacent beads whose positions are extremely difficult to control, as shown in Figure 2. , the complete tempering effect can be obtained by simply raising the end bead upwards.

)2) The final bead layer on the top surface of the caul plate has no tempering effect, but since it is removed by machining, the entire joint is tempered and becomes a good weld, making it possible to weld high-toughness joints without annealing using a simple method. becomes possible.

Next, the effects of the above-mentioned method of the present invention will be explained in the following examples.

Example 4 TIG welding was performed on 5% N1@ steel by the method shown in FIGS. 3 and 4 using a matching wire as the welding wire. During the welding process, no preheating was performed. As a result, the Hv of both cut material and welded metal was 180 to 22.
It was possible to obtain a high-toughness welded joint without annealing. In addition, the impact value of weld metal and heat affected zone is
It was about 1oky-m or more at -100°C, and an excellent high-toughness joint could be obtained.

Using materials similar to those described above, TI is
σ welding was performed. If the position of the next layer bead 4 in FIG. 1 is too far away from the end bead 3, the tempering effect at the welded end of the upper surface of the base metal will be insufficient, and a part of the base metal and the end bead will harden at about 340 Hv. Therefore, it was not possible to obtain a joint with excellent high toughness.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams of a conventional welding method for ensuring high toughness without annealing. FIGS. 3 and 4 are explanatory diagrams of the welding method for ensuring high toughness without annealing according to the present invention. Sub-Agents 1) Meifuku Agent Ryo Hagiwara - Figure 3

Claims (1)

[Claims] In the welding method for ensuring high toughness without annealing of steel materials, when welding the welding end of the upper surface of the base metal, a patch plate is installed at the relevant part, and the previous layer and a part are sequentially laminated and welded, and then the final welding is performed. A welding method that ensures high toughness without annealing, which is characterized by removing the bead layer and the corresponding plate.