DE2811406B2 - Wire and powder welding combination for submerged arc welding and methods for welding pipeline steels using such a combination - Google Patents

Description

and 0.3% by weight iron oxide.

A method for submerged arc welding of high-strength, low-alloy pipeline steels using the above-mentioned wire-welding powder combination is characterized according to the invention in that a welding powder with a content of 25 to 50% by weight of silicon dioxide, 24 to 18% by weight of calcium fluoride , 0 to 20 wt .-% manganese, 0 to 20 wt .-% of titanium dioxide, 1.0 to 25 wt .-% aluminum oxide, 10 ₁ O to 35.00 wt ° / o calcium oxide and ι ο 0 to 20 Wt .-% magnesium oxide is applied, that a wire connected in tandem is then brought through the welding powder into contact with the pipeline steels to initiate the submerged arc, each wire consisting essentially of 2.0 to 34 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 24 up to 3.5% by weight the silicon content is between 0.01 and 14% by weight and, in the case of a manganese content, between 2.0 and 24 Wt .-% of

Table I.

Silicon content greater than 0.3% by weight up to 14% by weight is and that then for a relative movement between the wires and pipeline steels with the formation of a Weld metal is taken care of, which at -25 "C a Has an impact strength of at least 4.1 J.

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 components, the wire Elements such as molybdenum (0.1 to 04% by weight) 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 in more detail below with reference to preferred exemplary embodiments Compositions are in each case given in% by weight.

Typical suitable wire compositions are listed in Table I.

sample C. No. A. 0.10 B. 0.091 C. 0.099 D. 0.098 E. 0, Iv /

2.27
2.52
3.03
3.03
2.48

0.35
0.37
0.31
0.34
0.61

0.50

Ο, ΪΟ

0.011 0.005 0.013 0.004 0.010 0.004 ο, οιο ¹ 0.004 0.013 0.004

Table II below shows the composition of typical welding powders used in conjunction can be used with the wires according to table r. In addition, the ^ Xabelle II contains the well-known

Table II

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.

B =

component Welding powder 2 3 4th 5 8.0 I. 22.2 - 14.1 27.6 MnO 12.3 34.3 39.9 39.4 21.6 SiO ₂ 40.1 4.8 2.5 3.0 20.0 AIjO, 5.1 13.2 33.8 24.0 9.0 CaO 17.6 4.7 11.3 9.2 1.0 CaF ₂ 4.6 12.5 11.9 7.9 - TiO ₂ 18.9 0.3 - 0.5 1.0 BaO - 1.8 0.3 1.0 FeO 1.1 - 11.8 ZrO ₂ 0.1 - 0.3 - MgO - - - 1.1 Na ₂ O - 0.6 0.96 0.9 1/2 (MnO + FeO) Basicity B 0.6 BaO + CaF ₂ + Na ₁ O + K ₂ O + CaO + MgO +

SiO ₂ + 1/2 (AI ₂ O ₃ + TiO ₂ + ZrO ₂ )

Based on the above data, it was determined that a presently useful welding powder should be in the range of the chemical compositions given below.

TiO ₂ 0-20% AI ₂ O ₃ 1.0-25% CaO 10.0 - 35.00% MgO 0-20%

SiO ₂
CaF ₂
MnO

25-50%
2.5-18%
0-20%

Tests were carried out on a high-strength, low-alloy steel with the following composition:

Mn

Si

Cu Ni

Cr

Mc

Al

Cb

1.27

0.006

0.005 0.26

0.10 0.07

0.09

0.29

0.017 0.038

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

When the wire B was used in conjunction with the welding powder I, a notched impact strength became of 6.8 J at -25 ° C. If wire B was used in conjunction with welding powder 3, The result was a notched impact strength of 6.1 J at -25 ° C. When using wire C in conjunction With welding powder 1, a notched impact strength of 7.5J at -25 ° C was achieved Wire C in combination with welding powder 3 resulted in a notched impact strength of 10.8 J -25 ° C. When the wire D was used together with the welding powder 1, one resulted Notched impact strength of 6.1 J at -25 ° C. The use of the wire D together with the welding powder 3 resulted in a notched impact strength of 10.8 J -25 ° C. If the wire E ^ i was combined with the When welding powder 1 was used, a notched impact strength of 5.7 J at -25 ° C. was obtained. The usage of wire E in connection with welding powder 3 had a notched impact strength of 12.2 J at -25 ° C iur consequence.

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 submerged arc welding of high-strength, low-alloy pipeline steels, the wire being essentially made of manganese, silicon, and carbon Iron is made up of welding powder and silicon dioxide, calcium fluoride, calcium oxide and aluminum oxide contains, characterized in that the wire has a content of substantially 2.0 to 3.5 Wt% manganese, 0.01 to 1.5 wt% silicon, 0.05 to 0.15 wt .-% carbon, remainder iron, with in the case of manganese contents of more than 24 up to 34% by weight of the silicon content between 0.01 and 14 wt% and in the case of one Manganese content between 2.0 and 24 wt .-% of the Silicon content is greater than 03% by weight up to 14% by weight, and that the welding powder is in the range of the following chemical compositions: 25 to 50% by weight silicon dioxide, 24 to 18% by weight Calcium fluoride, 0 to 20 wt% 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 of over 0.3 up to approximately 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 Wt .-% silicon dioxide, 24 wt .-% aluminum oxide, 33.8 wt .-% calcium oxide, 1U wt .-% calcium fluoride, 113 wt .-% titanium dioxide and 03 wt .-% 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, 24 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 weight percent calcium oxide and 0 to 20 wt .-% magnesium oxide is applied, that then a wire connected in tandem is brought into contact with the pipeline steels through the welding powder to initiate the submerged arc, each wire in the essentially from 2.0 to 3.5% by weight manganese, 0.01 to 1.0% by weight silicon, 0.05 to 0.15% by weight Carbon, the remainder being iron, whereby in the case of manganese contents of more than 24 up to 34 wt .-% the silicon content is between 0.01 and 14% by weight, and in the case of a manganese content between 2.0 and 24 wt .-% the silicon content is greater than 03 wt .-% up to 14 wt .-%, and that then for a Relative movement between the wires and pipeline steels with the formation of a weld metal it is ensured that at -25 ° C an impact strength of at least 4.1 | Has. 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 is made up and the welding powder contains silicon dioxide, calcium fluoride, calcium oxide and aluminum oxide, and a process for submerged arc welding of high-strength, low-alloy pipeline steels using ο dung such a wire-welding flux combination. In a known wire-welding powder combination of this type (DE-PS 8 64 646) is a silicon alloy Wire with a silicon content of 04 to 4.0% and, if necessary, 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 μ high-strength, low-alloy steels comes next high welding speed and the achievement of smooth, largely flawless weld seams, in particular on ensuring 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 with the achievement of better ten impact strength properties combined. According to the invention, this object is achieved by that the wire has a content of essentially 2.0 to 34 wt .-% manganese, 0.01 to 14 wt .-% silicon, 0.05 contains up to 0.15% by weight carbon, the remainder being iron, where in the case of manganese contents of more than 24 to to 34% by weight the silicon content is between 0.01 and 14% by weight, and in the case of tines manganese content between 2.0 and 24% by weight the silicon content is greater than 03% by weight up to 14% by weight, and that the W welding powder is in the range of the following chemical compositions: 25 to 50% by weight silicon dioxide, 24 to 18% by weight calcium fluoride, 0 to 20% by weight manganese oxide, 0 to 20% by weight titanium dioxide, 1.0 up to 25% by weight aluminum oxide, 10.0 to 35.00% by weight «5 calcium oxide and 0 to 20% by weight magnesium oxide. The wire-welding flux combination according to the invention ensures excellent notched impact strength values without adverse effects of the weld metal comes, for example, to micro seige and thus for training -on hard spots, 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. Overlap or waviness of the weld metal along the weld seam are avoided. The welding powder preferably has a basicity number from over 03 up to approximately 1.0. A combination in which the wire has a content of essentially proved to be particularly favorable 0.10 wt% carbon. 2.48% by weight manganese and 0.61% by weight silicon and in which the in ^h> connection with the wire used welding powder consists essentially of 39.9 wt .-% silica, 2.5 wt .-% aluminum oxide, 33.8 wt ° / o calcium oxide. 11.3 wt% calcium fluoride, 11.9 wt% titanium dioxide