DE1207770B - Welding electrode made of bare steel wire for inert gas arc welding under carbon dioxide - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

B 23 k

German class: 49 h -36/01

Number: 1207 770

File number: W 27159 VI a / 49 h

Filing date: February 1, 1960

Opening day: December 23, 1965

Steel wires are known for welding under protection from carbon dioxide, from mixtures Carbon dioxide with argon or helium gas or mixtures of carbon dioxide, argon and diatomic Gases such as oxygen or hydrogen. The steel wires have a silicon content of 0.5 to 2% and 0.5 to 3% manganese. These wires can only be welded at the positive pole of the direct current, while welding at the negative pole of the direct current or the alternating current is not possible. At the With the positive pole of the direct current, the drop transfer takes place in the form of a short circuit. This short-circuit-shaped drop transition results in heavy losses through splashing of the liquid weld metal. This splash causes post-processing costs. A drop transition in the arc, which avoids these disadvantages, is desirable not has.

Also additions of agents that reduce the drop size according to general knowledge, such as Oxides on the surface of the wire or the addition of oxygen to the gas were unsuccessful. There are also filler wires for inert gas arc welding in a mixture of carbon dioxide and oxygen are known, which in addition to 0.7 to 5% Mn and 0.25 to 5% Si also contain 0.00 to 5% Ti, a deoxidizing agent from the group consisting of aluminum, calcium, magnesium and zirconium being present should be. This is primarily intended to avoid pores in the weld metal.

Welding wires with so-called control metals, such as lanthanum, on their surface to ionize the arc section Rubidium, cerium or cesium, in small amounts, e.g. B. 0.005% rubidium, were applied, could under argon or another noble gas at the negative pole of the direct current or the alternating current be welded. The highest deposition rates were achieved on the negative pole with particularly low quantities to control metal, e.g. B. at less than 0.005% rubidium and moderate silicon contents of about 0.3 to 0.6% achieved. A proper welding of such wires in a carbon dioxide atmosphere is but not possible, especially not at the negative pole.

The invention relates to a bare welding wire, which is in a protective gas atmosphere of carbon dioxide, of mixtures of carbon dioxide with argon or helium gas or mixtures of carbon dioxide, Argon and diatomic gases such as oxygen and hydrogen are excellent at the negative pole or can be welded to alternating current.

The welding electrode according to the invention consists of bare steel wire, the usual amounts of carbon welding electrode made of bare steel wire for gas-shielded arc welding
Carbon dioxide

Applicant:

Westfälische Union Aktiengesellschaft
for iron and wire industry,
Hamm (Westphalia), Wilhelmstrasse 2

Named as inventor:
Dr.-Ing. Werner Hummitzsch,
Franz Mersmann, Hamm (Westphalia)

material, not more than 0.03% phosphorus, not more than 0.03% sulfur, 0.03 to 0.25% cerium, 0.7 to 2% silicon, Contains 0.8 to 4% manganese and the remainder iron. However, some of the iron can be replaced by titanium, vanadium, Zirconium, aluminum or antimony each in amounts of 0.01 to 0.4% individually or in mixtures be replaced. If several of these additional elements are present, the total amount should not be 0.4% exceed. The additions must be chosen in such a way that by their presence the presupposition of a Welding at the negative pole of the direct current is not adversely affected. Are preferred for the Carbon content 0.08 to 0.13%, for the cerium content 0.08 to 0.15% and for the silicon content 0.85 to 1.3%. The wires can also contain chromium or molybdenum or both, up to 2.5% Chromium and up to 1% molybdenum. Conventional carbon contents mean such as those in steel-iron material sheet 880-59 for single-alloy steels, or at Melier, »Electric Arc Welding«, 1932, pp. 137 to 141, number tables 8 to 11, and Zeyen - Lohmann, "Schweiß der Eisenwerkstoffe", 1943, p. 70, number table 4, are given.

Cerium is not added to the steel wire for reasons of deoxidation. Steels with more than 0.7% Si and more than 0.8% Mn are so well deoxidized that they are a further addition of one Do not need any stronger deoxidizer. The cerium content of the steel wire serves rather than Arc column ionizer. The presence of cerium ions in the arc results in a weld

5u of the wire at the negative pole of the direct current or at the Alternating current possible. In the absence of cerium, this wire cannot be connected to the alternating current or the minus

509 759/313

pole of the direct current are welded. A cerium alloy wire also has the property that it cannot be welded to the positive pole of the direct current. The characteristic property of these welding wires consists in the particularly good weldability at the negative pole of the direct current. You are the Wires that are welded at the positive pole are far superior. This is expressed in the very fine drop transition from and in the very low spray losses.

The fine droplet transition results in nicer and more even seam shapes than with positive pole welding of the previously known wires. Also, the welder can start the process of welding easier to handle, as there is a regular flow of the droplet in the arc and thereby the Arc burns more stable.

Among other things, the following wires were tested for their weldability:

description C. Si Mn P. S. Ce ° / o Negative pole Positive pole % ⁰ zo ° / o ° / o ° / o ° / o amp amp 43 212 0.08 0.23 1.08 0.032 0.010 0.08 320 330 43 314 0.09 0.83 1.25 0.015 0.017 0.08 0.05 Ti 300 300 43 216 0.10 1.01 1.18 0.019 0.022 0.09 0.03 zr 310 300 42 418 0.12 0.75 1.34 0.011 0.011 0.14 0.09 Al 335 310 1849 0.08 0.95 1.27 0.022 0.023 0.10 0.02Al 305 305 +0.03 Sb 43 211 0.08 0.93 1.34 0.029 0.027 0.08 - 300 300 2 248 0.11 0.93 1.26 0.010 0.019 0.13 - 330 310 1816 0.13 1.02 1.32 0.015 0.021 - - 210 290

In the last two columns of the table above, the currents in amperes are given at 1.6 mm Wire diameter result in an hourly deposition rate of 5.15 kg. Can be seen from this list one that even at the negative pole sometimes higher currents are required to achieve the same deposition rate to obtain. From this it follows that an increase in the performance of melting in this way and manner is not always achievable.

The sometimes somewhat reduced deposition rate is offset by the reduced reworking caused by spattering losses. In addition, it is hardly necessary to clean the gas nozzle. The easier handling of the welding torch results in a significant advantage in the overall performance, as a result of which the welder is less fatigued and thus a higher performance is achieved overall. The last composition listed under the designation 1816 is a wire that has been customary up to now, which requires a significantly lower amount of current at the negative pole than at the positive pole. However, the weldability is so poor that it cannot practically be used for this purpose.
With a wire of the following composition:

0.11% C, 0.93% Si, 1.26% Mn, 0.010% P, 0.019% S, 0.13% Ce and 0.02% Al, were the following quality values in the pure weld metal when welding at the negative pole achieved:

Glow state Stretch limit
kg / mm ² strength
kg / mm ² strain
(/ = 5 d )
° / o Constriction
% Not annealed 44.0
36.6
32.8 53.5
47.6
47.4 27.8
30.6
33.8 52.4
68.6
65.3 4 hours / 650 ⁰ C / furnace cooling
1 hour / 920 ⁰ C / furnace cooling

The notched impact strength of the pure weld, tested at +20 ⁰ C, gave the following values: 9.8; 10.2; 12.1; 13.5; 13.1; 11.8; 11.1; 9.2; 12.5; 11.8 mkg / cm ² .

The following composition was determined analytically for the melted weld metal:

C ..
Si ..
Mn
P ..
P.
Ce.

0.07%

0.54%

0.87%

0.009%

0.19%

0.04%.

55

The table contains under the designation 43 212 a wire which has only 0.23% Si at 0.08% Ce. This wire probably needs a lower amperage at the negative pole than at the positive pole. But he has for it a restless and unstable burning arc. In addition, spatter occurs during welding. the Sweat itself is porous. For a perfect drop transfer and a welding with low Wires with Si contents of 0.7% and above are necessary for spray losses. Only metallurgically perfect seams can be obtained.

Claims (3)

Patent claims: 1. Welding electrode made of bare steel wire for arc welding at the negative pole of the direct current or alternating current under a protective gas atmosphere of carbon dioxide, of mixtures from carbon dioxide with argon or helium or mixtures of carbon dioxide, argon and oxygen or hydrogen, characterized in that it consists of usual amounts of carbon, not more than 0.03% phosphorus, not more than 0.03% sulfur, 0.03 to 0.25% cerium, 0.7 to 2% silicon, 0.8 to 4% manganese, the remainder being iron. 2. Welding electrode according to claim 1, characterized in that it is made of a steel with a Composition according to claim 1, which, however, also contains 0.01 to 0.4% titanium, vanadium, Zirconium, aluminum or antimony or mixtures of the elements mentioned in the 5 6 mentioned amounts, however, in a total amount 5. Welding electrode according to one of claims 1 Contains from 0.01 to 0.4%. to 4, characterized in that the steel 3. Welding electrode according to claim 1 or 2, additionally up to 2.5% chromium and / or up to 1% characterized in that the steel contains 0.08 to molybdenum. Contains 0.13% carbon. 5 4. Welding electrode according to one of claims 1, documents considered:
2 or 3, characterized in that the steel is British Patent No. 824 038; 0.85 to 1.3% silicon and 0.08 to 0.15% cerium E. H ο u d r e m ο η t, »Handbook of Special Steel contains. künde ", 3rd edition, 1956, vol. 2, p. 1466. 509 759/313 12.65 © Bundesdruckerei Berlin