DE2811406C3 - Wire and powder welding combination for submerged arc welding and methods for welding pipeline steels using such a combination - Google Patents

Description

and 03 wt% iron oxide.

A process for submerged arc welding of high-strength, low-alloy pipeline steels using the above-mentioned wire-welding powder combination is according to the invention characterized in that a welding powder with a Content of 25 to 50% by weight silicon dioxide, 2.5 to 18% by weight calcium fluoride, 0 to 20% by weight manganese oxide, 0 to 20% by weight of titanium dioxide, 1.0 to 25% by weight of aluminum oxide, 10.0 to 35.00% by weight of calcium oxide and 0 to 20 wt .-% magnesium oxide is applied, that then a wire connected in tandem through the Welding powder through it is brought into contact with the pipeline steels to create the submerged arc to be triggered, each wire consisting essentially of 2.0 to 3.5% by weight of manganese, 0.01 to OK% by weight Silicon, 0.05 to 0.15 wt .-% carbon, remainder iron, consists, in the case of manganese contents of more than 2.5 up to 3.5% by weight of the silicon content between 0.01 and 1.5 wt .-% and in the case of a manganese content between 2.0 and 2.5 wt .-% of

Table I.

Silicon content greater than 0.3% by weight up to 1.5% by weight is and that then for a relative movement between the wires and pipelines to form a Weld metal is provided that has an impact strength of at least 4.1 J at -25 ° C.

In the case of the wire-welding powder combination according to the invention The contents of manganese and silicon are critical for the wire provided. In addition to the Above-mentioned constituents, the wire elements such as molybdenum (0.1 to 0.5 wt .-%) and / or Vanadium (0.05 to 0.20 wt%) or additional commonly used elements up to their known contain critical value. However, these elements are noteworthy for the notched impact strength properties achieved not essential.

The invention is explained below on the basis of preferred exemplary embodiments. the Compositions are in each case given in% by weight.

Typical suitable wire assemblies are listed in Table I.

Mn

Si

0.10

0.091

0.099

0.098

0.10

2.27
2.52
3.03
3.03
2.48

0.35
0.37
0.31
0.34
0.61

0.50

0.10

0.011 0.0Oi 0.013 0.004 0.010 0.004 0.010 0.004 0.0 Π 0.004

Table II below shows the composition of typical welding powders used in connection can be used with the wires shown in Table I. In addition, table II contains the known Formula for determining the acidity or basicity of welding fluxes. Four of the specified compositions have a basicity number less than 1 and are therefore to be addressed as acidic.

fciholle Il Scliw ei - UimlVLT .1 4th S. 8.0 - 1.1 component 1 - 2 - 14.1 27.6 11.8 12.3 0.6 22.2 39.9 39.4 21.6 - MnO 40.1 34 ^ 3 2.5 3.0 20.0 SiO, 5.1 4.8 33.8 24.0 9.0 Λ I, C), 17.6 13.2 11.3 9.2 1.0 CaO 4.6 4.7 11.9 7 * 9 CaI- ", 18.9 12.5 - 0.5 1.0 I'iO, 0.3 0.3 1.0 BaO 1.1 1.8 FcO 0.3 ZrO, 0.1 - - MgC) - 0.96 0.9 Well, 0 0.6 Basizilat B

CaO γ MgO + BaC) I- CaF, -I Na ₂ O! K ₂ O t- I 2 (MnO f FeO) SiO ₂ ι- 12 (Al ₂ O, \ TiO, I ZrO ₂ )

Based on the above data, it was determined that a presently usable welding powder should be in the range of the chemical / iiviMimcnsetzuiigeii mentioned below.

-, K). 2 ) iir :. I ..F 2, ^r ) ■ I8 »/ I MaO 0- 20%

IiCi, 0-20% AIjOi 1.0 - 2 ¹ Y ¹ Wed CaO 10.0- i-j.OO "/ MgO 0 20%

Attempts were made on a hoehlesieii. iiie
th steel of the following / iisaminensi-i / uni;
leads:

Mn

Si

Ni

Cr

Wed

Al

Cb

1.27

0.006

0X05 0.26

0.07

0.09

0.29

0.017

ύ.038

In this experiment, the wire compositions A to E according to Table 1 were used in conjunction with the two welding flux assemblies 1 and 3 of Table II, typical pipeline welding conditions for two-wire tandem submerged arc welding being used. On the inside wall of the tube, the front wire carried 850 A at 31 V. The second wire carried 700 A at 39 V. The welding speed was 1 m / min. On the outside wall of the tube, the front wire carried 1100A at 33V while the second wire carried 660A at 42V. The welding speed was 1 m / min. When the wire A was used together with the welding powder 1, the impact strength was 3.4] at -25 ° C. As a result, it is necessary to use a welding powder with a higher basic number such as welding powder 3 or 4 when the wire has a manganese content close to the lower limit of 2.0 wt% manganese. When using the wire A in connection with the welding powder 3, which has a Basizitätszahl of 0.96, resulted in an impact strength of 6.1 J at - 25 ⁰ C, which is amply above the usually benöiigten minimum value of 4.1 J.

When using wire B in conjunction with

A notched impact strength of 6.8 J at -25 ° C. was achieved for welding powder 1. When wire B is in When the compound with the welding powder 3 was used, the impact strength was found to be 6.1]

- 25 ° C. When using wire C in conjunction with welding powder 1, a notched impact strength of 7.5 J was achieved at -25 ° C. Using wire C in combination with welding powder 3 resulted in a notched impact strength of 10.8 J at

-25 ° C. When wire D was used together with welding powder 1, the impact strength was 6.1 J at -25 ° C. The use of the wire D together with the welding powder 3 resulted in an impact strength of 10.8 J

- 25 ° C. If the wire E was used in combination with the welding powder 1, a notched impact strength became of 5.7] at -25 ° C. The use of the wire E in connection with the welding powder 3 resulted in a notched impact strength of 12.2 J at -25 ° C.

From the above data it follows that the cheapest wire-welding flux combination is the Wire E and the welding powder 3 is.

Claims (4)

Patent claims: 1.Wire and welding flux combination for interpowder arc welding of high-strength, low-alloy pipeline steels, the wire being essentially made of manganese, silicon, and carbon Iron is made up and the welding powder consists of silicon dioxide. Calcium fluoride, calcium oxide and aluminum oxide contains, characterized in that the Wire has a content of essentially 2.0 to 3.5% by weight manganese, 0.01 to 1.5% by weight silicon, 0.05 has up to 0.15% by weight of carbon, the remainder being iron, in the case of manganese contents of more than 2.5 up to 3.5% by weight, the silicon content between 0.01 and 1.5% by weight and, in the case of a manganese content, between 2.0 and 2.5% by weight Silicon content is greater than 0.3 wt% up to 1.5 wt%, and that the welding powder is in the range the following chemical compositions: 25 to 50% by weight silicon dioxide, 2.5 to 18% by weight Calcium fluoride, 0 to 20% by weight manganese oxide, 0 to 20% by weight titanium dioxide, 1.0 to 25% by weight Alumina, 10.0 to 35.00 weight percent calcium oxide and 0 to 20 weight percent magnesium oxide. 2. Combination according to claim 1, characterized in that the welding powder has a basicity number from above 0.3 up to about 1.0. 3. Combination according to claims 1 and 2, characterized in that the wire has a content of im has essentially 0.10% by weight carbon, 2.48% by weight manganese and 0.61% by weight silicon and that the welding powder used in connection with the wire consists essentially of 39.9 % W / w silicon dioxide, 2.5% w / w aluminum oxide, 33.8% w / w calcium oxide, 11.3% w / w calcium fluoride, 11.9% by weight titanium dioxide and 0.3% by weight Iron oxide. 4. Process for submerged arc welding of high-strength, low-alloy pipeline steels using the wire-welding powder combination according to claim 1, characterized in that that a welding powder with a content of 25 to 50 wt .-% silicon dioxide, 2.5 to 18 wt .-% Calcium fluoride, 0 to 20% by weight manganese oxide, 0 to 20% by weight titanium dioxide, 1.0 to 25% by weight Alumina, 10.0 to 35.00 wt% calcium oxide and 0 to 20 wt .-% magnesium oxide is applied, that then a wire connected in tandem through the welding powder is brought into contact with the pipeline steels to create the submerged arc to trigger, each wire consisting essentially of 2.0 to 3.5 wt.% manganese, 0.01 to 1.0% by weight silicon, 0.05 to 0.15% by weight carbon, the remainder being iron, in the case of Manganese contents of more than 2.5 up to 3.5% by weight of the silicon content between 0.01 and 1.5% by weight is, and in the case of a manganese content between 2.0 and 2.5 wt .-% the silicon content is greater than 0.3 % By weight up to 1.5% by weight and that then for relative movement between the wires and pipeline steels with the formation of a weld deposit that has an impact strength at -25 "C of at least 4.1 J hai. The invention relates to a wire and welding powder combination for submerged arc welding of high-strength, low-alloy pipeline steels, the wire being essentially made of manganese, Silicon, carbon, and iron are made up, and welding powder is made up of silicon dioxide, calcium fluoride, and calcium oxide and aluminum oxide, as well as a method for submerged arc welding of high-strength, low-alloy pipeline steels using such a wire-welding flux combination. In a known wire-welding powder combination of this type (DE-PS 8 64 646) a silicon alloy is used Wire with a content of 0.5 to 4.0% silicon and possibly a manganese addition of up to 4% intended. The welding powder contains about 45 to 55% silicon dioxide, 25 to 35% calcium oxide as well as Balance fluxes such as calcium fluoride, magnesium oxide and aluminum oxide. In the case of welds on pipelines made of high-strength, low-alloy steels, it comes next high welding speed and the achievement of smooth, largely flawless weld seams in particular to ensure high impact strength at low temperatures. In this regard the known wire-welding flux combinations were unsatisfactory. The invention is based on the object of creating a wire-welding powder combination which good weldability combined with the achievement of improved notched impact strength properties. This object is achieved according to the invention in that the wire has a content of essentially 2.0 to 3.5% by weight manganese, 0.01 to 1.5% by weight silicon, 0.05 to 0.15% by weight carbon, the remainder being iron, in the case of manganese contents of more than 2.5 up to 3.5% by weight, the silicon content between 0.01 and 1.5 Wt .-%, and in the case of a manganese content between 2.0 and 2.5 wt .-%, the silicon content is greater than 0.3% by weight up to 1.5% by weight, and that the welding powder is in the range of the following chemical compositions lies: 25 to 50% by weight silicon dioxide, 2.5 to 18% by weight calcium fluoride, 0 to 20% by weight Manganese oxide, 0 to 20% by weight titanium dioxide, 1.0 to 25% by weight aluminum oxide, 10.0 to 35.00% by weight Calcium oxide and 0 to 20% by weight magnesium oxide. The wire-welding flux combination according to the Invention provides excellent notched impact strength values without adverse effects of the weld metal, for example, micro-segregation and thus the formation of hard stains, which in turn could lead to stress corrosion cracking. The chemical composition of the Electrode does not include critical elements such as Ti, B. Ni, etc. The wire-welding flux combination allows high speed welding. The weldability is excellent. Undercuts or waviness of the weld metal along the weld seam are avoided. The welding powder preferably has a basicity number greater than 0.3 up to about 1.0. A combination in which the wire has a content of essentially proved to be particularly favorable 0.10% by weight of carbon. 2.48% by weight of manganese and O.bl% by weight of silicon and in which the in Connection with the wire used. · Welding powder essentially consists of 34.4 wt. "/». Silicon dioxide, 2.5% by weight of aluminum oxide, 33.8% by weight of calcium oxide, I 1.3% by weight potassium fluoride. 1 1.4 wt% titanium dioxide