DE1281246B - Use of a low-alloy welding wire for welding low-alloy, high-strength steels - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN MDWWt PATENTAMT Int. Cl .:

B 23 k

EDITORIAL

German KL: 49 h-35/30

Number: 1281246 "* ';

File number: P 12 81 246.3-24 (O "30845)

Filing date: November 2, 1960

Opening day: October 24, 1968

It is known that low-alloy, high-strength steels, such as those used for armor plates, shipbuilding panels, for example and the like on a large scale because of their high strength and otherwise favorable mechanical properties are used, are difficult or unsatisfactory to weld. Welding by hand with stick electrodes or automatically using a welding process Shielding gas when using commercially available welding wires does not lead to the required strength values the welding point. Arc welding processes including submerged arc welding were also used due to the embrittlement of the welding points when using commercially available welding wires and conventional slag powder by no means. It was found that the notched impact strength at low temperatures the welded joints were not satisfactory.

It was also found that they achieved according to known methods using conventional welding wires Welds in all types of heat treatments to which these welds are subjected can or must, leave a lot to be desired.

A process for the production of weld seams with high heat resistance on steels as the base material has already become known (Austrian patent 191230) , 6 to 1% copper, 0.8 to 1% manganese, 0.15 to 0.24% molybdenum, 0.001 to 0.06% tantalum, niobium or boron or titanium, with the weld seam in the form of covered or non-covered electrodes for this purpose a material is used which consists of about 0.12 to 0.25% carbon, 1.2 to 1.8% manganese, 0.3 to 0.6% silicon, 0.8 to 1.5% copper, 0, 8 to 1.5% nickel, 0.25 to 0.4% molybdenum, 0.002 to 0.08% tantalum, niobium, boron or titanium, the remainder iron and usual impurities, with the proviso that the copper content in the welding wire is higher than in the base material. It is formed at the welding point, an intermediate structure, which must be tempered at 550 to 65O ⁰ C to increase the strength properties of the weld.

The invention now brings the use of special low-alloy welding wires for welding low-alloy, high-strength steels, it has been shown that the carbon, sulfur and phosphorus content in the welding wire is critical for achieving high strength and flawless welded joints.

If this critical area becomes the iron companion - as it is brought about by the invention - via the use of a low-alloy
Welding wire for welding low-alloyed
high strength steels

Applicant:

General Dynamics Corporation,

Groton, Conn. (V. St. A.)

Representative:

Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse and

Dipl.-Chem. Dr. rer. nat. E. Frhr. v. Bad luck man,

Patent attorneys,

8000 Munich 90, Schweigerstr. 2

Named as inventor:

John T. Ballass,

Bernard J. Freedman, Groton, Conn. (V. St. A.)

Claimed priority:
V. St. v. America November 2, 1959,
dated October 21, 1960

steps, the result is a defective weld, which in terms of strength, notched impact strength and the like. Gives cause for complaint. The invention thus brings the use of a welding wire consisting of 0.15% carbon, up to 0.015% phosphorus, up to 0.015% sulfur, up to 0.8% silicon, 1.2 to 1.8% manganese, 0.5 to 1.2% nickel, 0.1 to 0.5% molybdenum, 0.4 to 1% copper, up to 0.15% chromium and 0.03 to 0.5% Deoxidizer in the form of zirconium, titanium, magnesium and / or calcium and / or 0.03 to 0.1% Aluminum, a total of only a maximum of 0.5% deoxidizer, the remainder iron, for the production of welds high tensile strength, good ductility and high notched impact strength down to low temperatures on low-alloy, high-strength steels, especially those with 0.15 to 0.3% carbon and 2 to 5% common alloying elements. In other words, the low-alloyed ones on the market Connect high-strength steels properly with the welding wire to be used according to the invention.

It has been shown that the manganese content of the welding wire is within the limit given above is critical. If the manganese content is lower, then there is an absorption of manganese for the basic

809 628/1484

material into the weld metal. If the content exceeds the critical value, the weld metal gives off manganese to the surrounding base material. The range from 1.2 to 1.8% manganese in the invention too using welding wire is therefore in terms of economy and the quality of the weld joint.

It was found that a certain nickel content increases the strength and notched impact strength of the weld metal. This applies to nickel quantities between 0.5 and 1.2%. With a lower nickel content, there is no significant amount Increase in strength and notched impact strength instead. A larger amount of nickel leads to no further increase in strength and notched impact strength and only makes the material more expensive.

When welding low-alloy steels of high strength by the arc welding process with the welding electrodes according to the invention, values in the order of magnitude of 70 to 82 kg / mm ² for tensile strength, 56 to 67.5 kg / mm ² for the 0.2 limit and 17 are achieved 8 to 23.5% for the strain (at a Prüfstablänge of 35.5 mm) at a constriction 48 to 58.9% i ^m weld metal as well as values from 0.0925 to 0.163 kg / m / mm for the notched impact strength at -73 ⁰ C according to Ch ar ρ y. With these properties, the welds obtained according to the invention on low-alloy steels of high strength are significantly more favorable than all welded joints of such steels that have become known up to now. The extraordinarily high notched impact strength in the cold is particularly noteworthy.

The use according to the invention of special welding wires for welding low-alloy Steels is shown using the following examples.

There were then the strength values of these weld once determined soon after welding and once after a lstündigen annealing at 650 ⁰ C. The values are compiled in Table 2.

Table 2

Tensile strength, kg / mm ²

0.2 limit, kg / mm ²

Elongation (measuring length 35.5mm),%

Constriction, ° / o

Vickers hardness, kg / mm ²

Notched impact strength
Charpy at -73 ° C, kg / m / mm

Example 2

75 57.5 20 52.3 247

0.12

After tempering

66 62 24.3 65.5 213

0.125

example 1

35

Heavy plates with a thickness of 25.4 mm made of a low-carbon steel called HY-80 (composition: 0.1 to 0.4% manganese, up to 0.22% carbon, up to 0.035% phosphorus, up to 0.04) were welded % Sulfur, 0.15 to 0.35% silicon, 2 to 2.75% nickel, 0.9 to 1.4% Chromr0.23JMs 0.35% _L molybdenum, remainder iron). The welding wire was about 4 mm thick.

The well-known submerged arc welding process was used and a commercially available, neutral flux, which has a grain size of 0.2 to 1.4 mm having. Welding was carried out with a heat supply of 16,000 joules / cm, /

- Table 1

welding wire
'. % Weld metal
% carbon
manganese
phosphorus
Sulfur .......
Silicon
nickel
chrome
molybdenum
copper
zirconium
iron 0.09
1.63
0.008
0.005
0.06
0.87
0.037
0.2.
0.55
(+ 0.36% as
Share of Cu
Coat)
0.22
rest 0.057
1.44
0.013
0.010
0.28
1.01
0.18
0.19
- 0.75
not measurable
rest

55

60 ; Table 3 shows the composition of the welding wire and the welding metal as obtained when welding a heavy plate 25.4 mm thick from a low-carbon steel HY-80 using a welding wire according to the invention of approx. 4 mm.

Table 3

welding wire
■ '·% Weld metal
% carbon
manganese
phosphorus
Sulfur.
Silicon
nickel
chrome
molybdenum
copper
zirconium
Iron ..; 0.096
1.54
0.015
:. 0.002
0.06
0.86
0.03
0.19
0.53
(+ 0.07% as
Share of Cu
Coat)
0.18
rest 0.065
1.30.
0.024
0.005 -
0.31
1.2
0.31 ...
0.22.
0.57.
not measurable
rest

The weld had the following strength values: Table 4

Tensile strength, kg / mm ² . 72.5

0.2 limit, kg / mm ² '63

Elongation (measuring length 35.5 mm),% 24.3

Neck,% 58.7

Vickers hardness, kg / mm ² 248

Charpy notched impact strength

at -73 ° C, kg m / mm 0.13

Example3

Again a 25.4 mm thick plate of HY-80 steel was made using a 4 mm thick plate

welding wire according to the invention by the submerged arc welding process welded with the commercially available neutral welding agent and a heat supply of about 21,000 joules / cm.

Table 5 shows the composition of the welding wire and the welding metal.

Table 5 (continued)

5 copper

Table 5

carbon
manganese
Phosphorus.
Sulfur ..

Silicon

nickel

chrome

Molybdenum.

welding wire

0.09

1.57

0.006

0.005

0.07

0.88

0.033

0.20

Weld metal

0 / / 0

Zirconium ¹⁰ iron

Welding wire %

0.55

(+ 0.21% as

Share of Cu

Coat)

0.24

rest

Weld metal

7 »

0.59

0.03 remainder

0.067 1.46 0.009 0.011 0.40 1.09 0.20 0.20

»5

The weld showed the following strength values: Table 6

Tensile strength, kg / mm ² 76.5

0.2 limit, kg / mm ² 58

Elongation (measuring length 35.5 mm),% 20

Neck,% 49.1

Vickers hardness, kg / mm ² 240

Notched impact strength according to Ch ar ρ y at -73 ° C, kgm / mm 0.12

Example 4 to

Table welding wire

example C. Mn P. Si S. Ni Cr Mon Cu Zr Al Ti Fe 4th
5
6th
7th 0.07
0.10
0.06
0.08 1.54
1.62
1.54
1.35 0.007
0.012
0.006
0.014 0.19
0.47
0.27
0.18 0.005
0.005
0.007
0.005 0.90
0.87
0.83
0.81 0.10
0.11
0.10
0.12 0.18
0.18
0.18
0.18 0.82
0.85
0.80
0.82 0.19
<0.01
<0.01
<0.01 0.01
0.05
0.038 0.051 rest
rest
rest
rest

Table weld metal

example C. Mn P. Si S. Ni Cr Mon Cu Zr Ti rest 4th 0.07 1.05 0.012 0.28 0.009 1.47 0.51 0.25 0.45 0.09 Fe 5 0.06 1.11 0.015 0.50 0.010 1.41 0.46 0.25 0.70 <0.01 - Fe 6th 0.05 1.01 0.013 0.38 0.012 1.15 0.38 0.23 0.74 0.01 - Fe 7th 0.04 0.98 0.013 0.36 0.009 1.21 0.29 0.22 0.90 <0.01 0.025 Fe

Plates 50.8 mm thick were welded from voltage 30 V, current strength 60 A and an electrical steel HY-80; Wire thickness of the invention 45 den feed speed of about 0.455 m / min. Welding wire 4 mm; Submerged arc welding process worked.

with a welding agent with a grain size of 0.42 to 2 mm. The strength properties of the

In Examples 4 to 6, the weld metal was welded both after cooling and after cooling

a heat supply of 31,000 joules / cm, voltage after a subsequent 4-hour glow

30 V, current 700 A, with the electrode over the 50 90 to 930 ° C, quenching in water and again

Shock at a rate of about 4 hours, tempering at 620 to 650 ° C and quenching

0.4 m / min. Example 7 was determined using (Examples 4 to 6). The values are in Table 9

a heat supply of about 23,500 joules / cm.

Tabel

Sweat train 0.2- strain
(Measuring length
35.5 mm)
7o A Charpy notched impact strength ir after heat treatment 65.7 0.472 -17.7 ° C -51 ° C ι kg m / mm wire
example strength
kg / mm ² border
kg / mm ⁸ 22.5 lacing
% space
temperature 23.5 42 0.5 0.294 0.2 -73 ° C 4th 74.0 60.3 20th 57.2 0.37 24 64.5 0.414 0.274 0.19 0.125 5 82.0 67.5 21 55.3 0.32 23 0.271 0.212 0.147 6th 75.0 63.5 23.5 56 0.328 0.271 0.185 0.157 7th 70.5 63.3 58.9 0.41 0.0925 0.374 0.195 4th 65 56.3 0.449 0.295 0.105 5 64.8 56.8 0.338 0.219 0.228 6th 66.3 58.5 0.13

In the examples, only the Unler powder welding process was used worked. It is of course also possible to use those to be used according to the invention Use welding wires in other welding processes, especially in gas-shielded welding. In this last-mentioned method, welding wires according to the invention with slightly less manganese can be used apply according to the invention, because with submerged-arc welding processes the burn-off of manganese is greater than with inert gas welding. If you want to work according to the electroslag welding process, this is the case it is appropriate to use a welding wire according to the invention To apply composition with flux jacket or a flux core and the Flushing the wire with shielding gas during welding.

Claims (3)

Patent claims: 1. Use of a welding wire from ^fl to 0.15% carbon, up to 0, _'015/0 phosphorus, up to 0.015% sulfur, up to 0.8% silicon, 1.2 to 1.8% ^EO manganese, 0.5 to 1.2% nickel, 0.1 to 0.5% molybdenum, 0.4 to 1% copper, up to 0.15% chromium and 0.03 to 0.5% deoxidizer in the form of Zirconium, titanium, magnesium and / or calcium and / or 0.03 to 0.1% aluminum, in total only a maximum of 0.5% deoxidizer, remainder iron, for the production of welds with high tensile strength, good ductility and higher notch impact strength down to low temperatures on low-alloy, high-strength steels. 2. Use of a welding wire of the composition specified in claim 1 for the in the purpose mentioned in claim 1, wherein the steels to be welded 0.15 to 0.3% carbon and contain 2 to 5% common alloying elements. 3. Use of a welding wire of the composition specified in claim 1 with 0.03 up to 0.5% zirconium or titanium or 0.03 to 0.1% aluminum, the latter possibly combined 0.03 to 0.5% zirconium, the total content not exceeding 0.5%, as a deoxidizer for the purpose mentioned in claim 1 or 2. Considered publications:
Austrian patent specification No. 191 230.