JPS59212176A - Submerged arc welding method - Google Patents

Abstract

PURPOSE:To improve welding efficiency without welding defects in multi-layer two-electrode submerged arc welding by specifying wire diameter, etc. and making the space between a succeeding electrode and the wall face of a groove smaller than the spacing between the preceding electrode and the wall face of the groove. CONSTITUTION:The wire diameters of a preceding electrode L and a succeeding electrode T are set at 1.2-3.2mm., welding current is set at 200-600A, welding speed at 40-70cm/min and the distance between the electrodes at 5-30cm in multi-layer two-electrode submerged arc welding for joint welding of extra- thick steel plates, etc. The electrodes L, T are disposed in such a way that the space TW between the succeeding electrode T and the wall face 1a on the groove side is smaller than the space LW between the preceding electrode L and the wall face 1a on the groove side in proximity thereto. Generation of an undercut, etc. is prevented in the narrow groove by such welding method, by which a satisfactory weld zone is formed.

Description

[Detailed Description of the Invention] The invention is directed to a multilayer two-electrode arc welding method, particularly i:
! l < ノ ≠ Shrine board 2 # When using a hand bath, the slag removal work can be easily done with a small amount of money, and it is highly efficient.
The present invention relates to a welding method capable of producing a bimodal bath weld.

The multi-layer welding γ6 method has been adopted for bath welding joints of thick steel plates, but recently various improvements have been proposed, including low welding costs. One of them is the root 1iti IIn 12 r as shown in FIG.
r, : nl, jiJ The groove part with the tip angle of 8° is steel plate 1.1'
1 by submerged arc welding method.
This is a method of making a multi-layer stack T11 using the 1if layer method of the 1st bus, and also the method of N, Su (machi), as shown in Figure 82.
In this method, a groove with a root interval of 24 mm and a groove angle of 2° is welded in multiple layers using a two-electrode submerged arc welding method using a one-layer, two-bus bonding method. In addition, in 1/U, 2 (ma) is a weld bead.

However, there is one thing to be said about all of these methods; none of them are completely satisfactory. Jchi, tI.

Regarding the time required for contact, L4 has a groove cross-sectional area that is almost twice that of 1JJ, but 1JL4. Since ga is bracket (z/T1.), it can be said that it is equivalent to L7.
However, there is a method that reduces the required amount of 9m folding material by half to +iiJ%. However, on the contrary, for example, yen l51
) shape (1°η) When welding the circle I+￥1 joint part of the structure, +JiJ crystal (・址、1′ circumscribing sufugu 8) must be removed, so a full-time worker is required to do so. On the other hand, in the latter case, the bath contact slag δ normally falls naturally, so unlike the former case, an operator is not required, and even in the unlikely event that the bath contact conditions are controlled or monitored. It is enough to perform the necessary work with only one worker.In this way, even if the cost of welding materials is reduced in the former case, two workers are required, so the labor cost is 20% compared to the latter one. In terms of total cost, the latter is more advantageous.

Therefore, F'JiJ workers cannot perform welding effectively even with two workers, and the welding metal 2 is prone to moisture cracking and is not healthy. However, even in the latter case, if the placement positions of the leading electrode and the trailing electrode are changed, the 64-connection order may be accompanied by undercutting, slag entrainment, etc. There are drawbacks such as deterioration in slag removability.

Therefore, the present inventors have completely solved the various drawbacks of the prior art mentioned above, and it is possible to weld a narrow gap with only one operator and without causing welding defects. After intensive research on the multi-layer welding method in which a sound weld is damaged, we found that it is advantageous to perform polar submerged arc welding using the one-layer, two-bus lamination method within a narrow gap. Besides that, ■ In addition to controlling the width of the bath bead to be small,
Furthermore, r'd such as undercuts and slag entrainment, etc.
F & defect 2 prevention T, trailing V4 with respect to leading electrode
It was discovered that the arrangement 1·t of the i-pole is important, and the present invention was achieved.

That is, the gist of the present invention is that in the multi-layer stacked 2-electrode/h-arc welding method performed by the 1-layer 2-bus lamination method, the diameter of the electrode wire can be reduced even in winter for the leading electrode and the trailing electrode. 1.2-3.2, rW contact current 200-eooA
, the welding speed was set to 40 to 70 c+n/m1rl, the distance between the electrodes was set to 5 to 80 am, and the force) was 1ii
Welding is performed by arranging the electrodes such that the distance between the trailing pole and the groove side wall surface 1jJ is smaller than the distance between the leading pole i and the groove side 11'4 adjacent thereto. ′? i: A narrow 1-point, 2-ton, full-arc welding method characterized by:

The present invention will be explained in detail below.

First, FIG. 3 shows the groove shape and lamination method in the present invention. The groove portions of steel plates 1 and 1' have a root interval W.

It has a narrow groove shape with a groove angle θ (H is the root face), and is performed by a lamination method in which weld beads 2 are sequentially formed in one layer using a two-bath method. In addition, Lou) 11j
As the distance W increases, the removability of the slag 3 improves,
Since welding efficiency is adversely affected, the root spacing W is preferably 17 mm or less. However, when T is smaller than 10Tnm,
In the case of circumferential joint bath welding, welding slag δ naturally falls and separates.
As a result, you will be able to spend more effort than just one slug. The groove angle θ is also the same, and is preferably 15° or less; if it is wider than 15°, welding efficiency will be impaired and it is not economical.

? The capacitor 7a has two electrodes as shown in FIG.

(Note that T 117 is located at the front of the welding direction α.
, Let the pole be the leading pole, and let the pole located behind it be the point. ] The wire diameter used for 11 city poles is 1.2 to 8.2w. If you make it thinner than 1.2, lti is 1 direction, T is 2! In order to bathe the groove side wall surface 1a of the steel plate l which has been adjusted to Lj, each electrode and the groove side wall surface 1a are connected to each electrode and the groove side wall surface 1a;
TVI' had to be less than 2 m+,
-There is a risk that the torch nozzle will come into contact with the groove surface and cause a short circuit.On the other hand, if it is thicker than J2mm-
In this case, the bead width becomes too wide, resulting in a bead shape similar to that of a 17-tone 1 bass head, which deteriorates the slag removability and makes it easy for slag entrainment to occur.

The welding current for each electrode is 200 to 600 A.

If it is smaller than 2.0OA, the groove 1+l of steel plate 1'
Since the insect surface 1'b and the front bath bead C cannot be sufficiently melted in the bath, poor fusion tends to occur, and the welding speed decreases, resulting in damage to the welding surface. If it is made too harsh, thermal cracking is likely to occur in the bath-welded bead 1-2, and in history, the bead width becomes too wide and the bead shape becomes J/1 smaller than the 11G/1 bath speed, resulting in slag peeling. One: It causes deterioration and slag entrainment is more likely to occur.

To set the welding speed to 40 to 70 Cm/min, 40
If the speed is slower than am/m i r+, the bead width becomes wider and the bead shape becomes closer to a bus bead, deteriorating the slag removability, and furthermore, slag entrainment occurs and becomes difficult. If the speed is faster than 70 cm/min, it will not be possible to sufficiently fuse the 1st side wall surface 1'b and the 2nd corner of the front.
This is because poor fusion is likely to occur and furthermore, the bead surface shape is disturbed.

The distance between the leading electrode and the trailing electrode T is within the range of 5 to 30 degrees. If it is smaller than 5, the force generated at each i'L pole causes interaction in the arc, making it unstable and causing welding defects. On the other hand, if the value is set higher than 80, the arc stability of the leading electrode is maintained, but the arc of the trailing electrode T is damaged by the welding slack generated by the leading electrode and becomes unstable. Since the bead shape also deteriorates, defects such as slag entrainment and poor fusion are more likely to occur.

Note that the arc stability is preferably about 28 to 36V. If the value is outside of this 1ml, short circuits may occur and poor fusion will occur (also, undercuts and slag entrainment may occur, which can be dangerous!). Kawamukai's a (convex'
) Any of them can be used for i:J4, and either -C, melting type Taisei or firing type flanks can be used as bath wetting flanks.

Even if welding is performed under each of the conditions explained above, under-
Bath contact defects such as cant and slag entrainment may occur. Therefore, the inventors conducted two 4:In experiments and found that in order to completely prevent the occurrence of these bath contact defects, the arrangement r1't of each electrode and T should be set to '1'. .5 fixed Seki〆.

This led to the realization that there was a need for regulation.

The experiment was conducted using plate thickness '/5 rntn (1) ASTM A
a87 Gr22 (0.14%G, 0.22%S1,
(1,43%)7111,o,ooa%P,0.008
%S, 2.25%Qr, 1. 21 board of t1%l0), θ-2°, W-15m, rn, H-10mm l)
Jgec, 1 shoe processed into cedar-bush (see Figure 3), 7 bus il # molding flux in Table 1 and ila B shown in Table 2
(1) Combine welding wires and perform arc welding under the welding conditions shown in Table 3 using the 2'::f 4ijlj 1'i'f arc welding method. '
By varying the distance LW between I and the trailing electrode T and the distance TW between the trailing electrode T, we inspected the occurrence of welding defects such as undercuts, poor fusion, and slag entrainment, as well as the location of each electrode. did. The result is shown in Figure 5.As is clear from Figure 6,
l, vinegar 1.゛If the 1st place RLW is ;3 mm (actual -
In both the 1 and 2 lines □1ii 1:u: T's placement position TV is located at the critical position iI! If the welding defect is smaller than J, i.e., closer to the groove side wall surface 1a, there will be almost no welding defects, but if it is larger, i.e., the welding defect will rapidly increase as you move away from the groove wall Ula. It can be seen that more defects occur. Then, the first ascending liquid j is located at the placement position L of the preceding electrode.
W is approximately 1iT (in the figure, the LW arrow refers to J results).

From the above experimental results, in the present invention, each "rji.

The IA between the pole placement positions is regulated, and the preceding i'l'i,, l
ii@ Distance L between L and the groove side wall surface 1a adjacent thereto
Arrange each city 4・j≦ so that the distance TV from the bale r'”flε to the pole T is smaller than w. By doing this, it is possible to obtain a good welded part by reducing the undercut etc. by 1＼ and IJ. 1 and 4. If the TV is made larger than Lw, welding defects such as 7' leakage and slag entrainment may occur. It is preferable to have a groove of 1 fi!
It becomes possible to sufficiently verify the I wall structure 1a and prevent the occurrence of common jd defects.

Next, an example of the present invention will be shown.〇Example plate thickness 75 am (1) ASTM A 516 G
r70 (0.19%G, 0.29%Si, 1.1
After processing a steel plate (6%Mn, 0.012%P, 10.008%S) into a groove shape of θ-2°, W-14m+x, H-10 (see Figure 8), the groove shape shown in Table 1 was prepared. Using a combination of the T-firing type flux and the TAA bath J' and wire shown in Table 2, 2-ton polar submerged arc welding of 1-layer, 2-bus multilayer welding was performed under the welding conditions shown in Table 4. . X#;! The presence or absence of welding defects was investigated by a transmission test, and the results are shown in Table 4.

Each of the Examples (A1 to A5) of the present invention had no or no welding defects. On the other hand, in comparative examples (Ban 6 to 8) in which any of the conditions of the present invention has a value outside the present invention,
Many defects such as slag entrainment and poor fusion occurred.

Omote (E) In the table, the underline is the condition KIα outside the present invention.
It means that.

Explanation 1--According to the present invention, the conventional +4'
Compared with not only the L-ton pole and arc bath welding method but also the multi-layer welding method using the two-ton pole arc bath welding method, the welded iB skewer can be significantly improved without any welding defects. Because only one person can perform the bath cleaning, it is possible to lower the bath cleaning cost and pay for the cost.
This is something that can be expected to have a significant effect.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams explaining the groove shape and lamination method in the conventional method. Figure 8 is a diagram explaining the groove shape and lamination method in the present invention. Figure 4 is the leading m pole in the present invention. and arrangement I of the trailing pole 7a
I' 2nd place fi" (This is a diagram explaining Seki 1 Ho,
1A is a front view, (B) is a plan view, and FIG. ■, 1'... Steel & 2... Bath welding bead 3.
Ntani 1 & Slag L... Leading type I Moe T... Trailing 'fly, I'm sorry. Figure 5 Tangent Electric Power 9 West Cl I'LJtTw

Claims (1)

[Claims] 1. In the multi-layer stacked two-electrode drilling method performed using the two-layer stacking method, the i'α pole wire diameter for both the leading and trailing electrodes is set to 1.2 to 3.2 mm. Net, welding 7
g current 200~600A, welding M degree 40~7 Q c
m/Din and the distance between the electrodes is 5 to 30 mm,
and an electrode device in which the distance between the leading electrode and the groove side wall surface is smaller than the distance between the leading electrode and the groove side wall surface adjacent thereto. So, do welding? Characteristic of the narrow gap 2-kick submerged arc welding force method.