DE1964751B2 - Arc welding process with high impact strength in the seam transition zone and electrode for this - Google Patents

Description

5. Application welding electrode for carrying out the steel to be welded, with the addition of of the method according to one of claims 1 to 4, that if the above-described is observed characterized in that the electrode does not entirely cover the disadvantages described Alloy of the following composition (%) can be eliminated borrowed

consists: 40 The invention thus relates to a method

for arc joint welding of high-strength steels, low-temperature steels and low-alloy steels through butt welds, which means it is characterized that a high notch impact-resistant steel alloy is first applied to each seam edge as a buffer layer welded on and then the seam joint is fully welded with a filler material adapted to the base material will.

The invention is explained in more detail with reference to the drawings. the

F i g. 1 to 3 show an embodiment of the welding method according to the invention;

F i g. Figure 1 shows in elevation a welded joint prior to the application of a high impact strength joint The invention relates to a new welding process, 55 steel alloy;

when it is carried out, the brittleness of the weld

ßung of high-strength steels, low-temperature steels, the application of high-impact steel or Similar low-alloy steels avoided alloying on every weld surface of the joint; will. F i g. 3 is an elevation of the connection after termination

One of the greatest technical difficulties involved in welding; the Welding such low-alloy steels, high-strength F i g. 4 and 5 show another embodiment

Steels or low-temperature steels consists in that form of the welding process according to the invention;
the notched impact strength of the welded joint in FIG. 4 shows a perspective view of how a

the cooling as a result of structural changes, high-impact steel alloy is applied is noticeably reduced. This means that as a result 65 and then the applied metal layers the influence of heat during welding on which the butt welds are welded;

bond a transformation structure of rough fig. Figure 5 is an elevation of the weld joint of Figure 5

Grain is generated and therefore also when the completion of welding; the

0 until 0.50 Cr, 0 until 0.80 Mo 0.05 until 0.16 C, 0.30 until 0.80 Si, 0.80 until 2.50 Mn, 2.50 until 10.00 Ni, 0.01 until 0.10 Al, Ti, V, Nb, Zr, rest Fe.

pig. 6 to 11 show another embodiment the welding method according to the invention;

a pi .6 is a plan view showing plates to be welded before welding;

ρ j »7 is a plan view of the plates around 5 W before the application of a high-impact steel alloy;

ρ ig. % is a vertical cross-section along the jink Vin-Vni as shown in FIG. 7 and shows the water build-up in the course of the application of the high-impact steel alloy;

ρ j β 9 is a plan view of the weld joint after the application of the high impact steel alloy;

Fig- 10 is ¹ ^ ⁶ top view of the connection prior to butt welding;

For 11 ^ ^eme looks at the joint after welding.

In carrying out the welding process according to the invention, the steel plates 1 and 2 which are to be welded and which are provided with a joint are juxtaposed with one another, with sufficient clearance 3 being provided between them. You are on a copper shoe 4 cooled with water, as shown in FIGS. 1 to 3 can be seen. Layers of a high-impact beam alloy 5 and 6 are first applied to the corresponding seam edges, whereupon the above-mentioned parts 5 and 6 are welded to one another by means of an introduced metal by some welding method in such a way that the steel plates 1 and 2 are completely applied over the Layers 5 and 6 are welded from a high-impact steel alloy.

The high-impact steel alloy layer 5, 6 is applied to the seam flanks of the steel plates 1, 2 in any desired thickness, the thickness depending on the dimensions and the composition of the steel plates to be welded. The welding can be carried out by various methods, for example by means of carbon dioxide arc welding, tungsten inert gas welding, metal inert gas welding, shielding gas arc welding with increasing weld pool and forced opening of the seam, submerged arc welding or plasma welding. The weld bond becomes brittle when the applied steel alloy layer cools, but it is heat-treated by the heat of the subsequent butt welding, so that the weld bond then has a high impact strength again. If the layer 5, 6; 13.14; 30, 31 is applied in a suitable thickness and then heated by the subsequent butt welding to a temperature above the / ica transformation point (approx. 900 ° Q, a welded joint with high notched impact strength is finally obtained After the application, it is cooled by water, then it is only ^{heated to a temperature below the / icr transformation point (approximately 65O 0} Q, so that there is no reduction in the notched impact strength as a result of the quenching and tempering effect. is a measure that is generally used to improve the notched impact strength of steel plates. How much the notched impact strength of a welded joint is improved by such a method is well known.

The following explanations explain a specific embodiment of the present invention with reference to the in FIG. 4 reproduced perspective view. A protective gas arc welding is carried out: The reference numerals 8 and 9 denote steel plates which are to be welded by bridging a joint opening between them. 10 is a copper shoe which is attached in such a way that a high-impact steel alloy can be applied to the seam flanks of the steel plates to be welded. This copper shoe has a length of a few 10 mm in the longitudinal direction and is attached in such a way that it can slide through the inert gas arc welding electrodes 11 and 12, which are located above the shoe, as the deposit increases. With 13 and 14 deposited layers of a high-impact steel alloy are referred to in this way. A protective gas arc welding electrode 15 for full welding of the seam is then attached in such a way that a butt weld can take place within a shoe 16, the shoe 16 sliding on as the welding progresses. With 17 the weld metal formed in this way is referred to. The weld seam is formed in this way by the applied layer of weld metal 17 and the applied layer 14. A cross-sectional view of the weld seam produced by the method according to the invention is shown in FIG. 5 shown. The welding bonds 18 and 19 are heated 900 ⁰ Q at the weld to a temperature above the zlrrUmwandlungspunktes (wherein the welding heat pass therethrough from the weld metal 17 by the applied layers 13 and 14 to the welding bonds 18 and 19 so that a normalization to form a fine grain structure, which makes it possible to avoid the bond breaking.

An embodiment will now be described, when implemented, a reduction in the Notched impact strength of the welded joint is prevented by a quenching and tempering effect will.

The difference between the second embodiment and the first embodiment is that the high-notch high-resistance steel alloy immediately after its application by a water cooling device is cooled. This embodiment is based on the horizontal and vertical cross-sections, such as they are represented by Figures 6 to 11,

explained. "

The steel plates to be welded 20 and 20 are each other with a certain joint spacing 22 compared, as shown in Fig. emerges. A copper shoe 23 in the shape of a 1 in cross section in the horizontal direction is between attached to the seam flanks of the steel plates 20 and 21 to be welded together, and in such a way that between the copper shoe and the steel plates 20 and 21 the free spaces and 25 are formed. This copper shoe has a length of a few 10 mm in the longitudinal direction and is attached to a vertically operating sliding

drive mechanism, which is not shown, attached metal, it is necessary to add silicon, closed in such a way that the shoe, if this addition is made in too large a quantity, can slide upwards as welding progresses. then non-metallic inclusions set the notch welding electrodes 26 and 27 are falling above the impact strength. Hence the Süicium rooms 24 and 25 attached. Cooling nozzles 32, 32 '5 addition up to a content of 0.30 to 0.80%. and 33,33 'for cooling the positions accordingly. Manganese is an element that is particularly useful for the kerf Impact strength is improved 10 mm below the electrodes. However, this item will attached below the copper shoe 23, so that too large an amount added, then hardens the these electrodes, the copper shoe and the water-applied metal alloy and tends to cooling nozzles as a unit in the vertical direction io cracking. It is therefore necessary to move the manganese can. limit the content to a maximum of 2.50%.

If nickel is added when using the above, then the notch impact

Device electrodes an electric current through the weld toughness without hardening the welded part 26 and 27, then a steel one will be mended. Hence, nickel is the most effective Alloy with a high notched impact strength from 15 elements. To achieve a high notch impact Electrodes on the seam flanks of the steel plates Toughness in welding methods such as those of the invention and 21, which are to be welded, applied, according to applied, it is necessary, little where the applied steel alloy 30 and 31 to add at least 2.50% nickel. If the nickel exceeds the Fills in rooms 24 and 25. However, as the content increases, the amount of austenite becomes 10.00% The electrodes, the copper 20, are welded too large, so that a difference between the expansion shoe and the water cooling nozzles in the upward direction is the coefficient of the applied metal as well as the moved at welding speed. Immediately after welded steel plate is produced. It is therefore the solidification of the applied steel alloy expediently, the upper limit of the nickel content will set this as well as the steel plates in their vicinity at 10%.

Quenched cooling water that passes through the nozzles 32, 32 '25. and 33,33 'is supplied so that the weld bond has a particularly high yield strength value gets a deterred structure. should have, the alloy appropriately contains

As can be seen from FIG. 10, there is vertically chromium and / or molybdenum, the chromium kai Sliding copper shoe 38 between the seam content at most 0.50% and the molybdenum content flanks of the applied steel alloy 30 and 31, 30 should be a maximum of 0.80%, otherwise the wherein a welding electrode (not shown) in the notched impact strength is reduced. Furthermore has a Space 39 in the upward direction together with the addition of Al, Ti, V, Nb and / or Zr in one Shoe 38 is moved. A usual amount of inert gas of 0.01 to 0.10% or more is more effective Arc welding in the room 39, by the wise one a refinement of the Crystal Koras as well as a Copper shoe 38 and the applied steel alloy 35 result in an improvement in the notched impact strength. 30 and 31 is formed, so that the Therefore these elements are applied as required Steel alloy 30 and 31 with a nits added in small amounts high notched impact strength with any desired The impact strength properties of the invention

Welding metal 40 (cf. FIG. 11) can be connected according to welded connections made. If the welding is carried out in the above-described curves of FIG. 12 in which the abbened manner is carried out, then the welding sorbed energy and the breakage rate are plotted against the membrane bonds 34 and 35, to which a quenched temperature is applied. Curve A gives the structure to be imparted to the deposits, impact resistance properties of an according to the invention tempered by the heat that acts during the welded joint produced during the closing butt welding, so that curve B represents the corresponding values of the steel plate structure of the welded joint in a deterred self shows. Curve C explains the corresponding and tempered structure is transferred and thereby values of a bond fragility carried out for comparison purposes is prevented. Welding, using a conventional shielding gas

The high-impact steel arc welding process is preferably used. From this alloy, which was previously applied to the seam flanks of FIG. 12, it is clear that the impact strength welding steel plates are welded on, significantly better from the properties of an alloy with 0.05 to 0.16% carbon, 0.30 welded joints produced according to the invention are as die to 0.80% silicon, 0.80 to 2.50% manganese and those of welded joints that have been produced according to conventional 24Ο to 10.00% nickel as main components, processes. In addition, such an alloy is less than 0.80% Mo 55 the values of the welded joints according to the invention and / or contains less than 0.50% Cr for the case that it is never below that of the steel plate that high strength is required. In total, when using a steel plate with a strength, such an alloy contains 0.01 to 0.10% or speed of 50 kp / mm ² and a thickness of 38 mm more of one of the elements AL Ti, V, Nb and Zr, (Test No. 3) and a steel plate with a strength while the remainder is composed essentially of iron 60 of 60 kg / mm * and a thickness of 45 mm (test number 5) are the impact strength values according to the invention

The reasons for the limitations on the welded joints made a little better than The ranges given above are as follows: shall be those of the steel plates themselves. This is, therefore, the In particular, if the notched impact strength is high, then FaIL is preferable because renewed heat treatment to the time the carbon content is low. However, 65 point of the butt welding should be according to the present to obtain sufficient strength of the invention, the structure of the steel plate is remarkable Carbon content improved in the range from 0.05 to 0.16%. To prevent pores in the above- The examples illustrate the invention.

Welding process

According to the invention

procedure

Usual procedure

Characteristic values

vTs

-15
68

v £ o
(kpm)

8.7
U

example 1

Steel plates with a tensile strength of 80 kgf / mm ² and a thickness of 32 mm (with a composition as shown in Table III under Test No. 1) are opposed to one another in such a way that they form a V-shaped joint form in a horizontal position. Each seam flank is welded at a welding speed of 500 mm / min using a 5% Ni wire with a diameter of 1.6 mm (the wire having the composition given in Table IV under Test No. 1) by means of a Carbon dioxide arc welding method applied a layer of a high-impact steel alloy. A butt welding is then carried out, the heat input being 150,000 joules / cm. The welding current of 3000 amps consists of 1200 A from the first electrode, 1000 A from the second electrode and 800 A from the third electrode. The arc voltage is 40 volts, while the welding speed is regulated to 500 mm / min. Welding electrodes with a diameter of 4.8 and 6.4 mm are used. A three-electrode submerged arc welding process is used about 300 mm behind. The welding heat of this butt welding gives the welded joint a normalized structure, so that brittleness is largely avoided.

On the other hand, a conventional welding method with a heat input of 150,000 joules / cm is used a conventional submerged arc welding method, but none Metal layer made of a high-impact steel alloy is applied. 2mm V-Notch Impact Tests the welded joints are then carried out. The results are in Table I. summarized

Table I.

The setting of this wire is shown in Table IV the test no. 2 emerges. In this way, a metal layer is made from a high-impact steel alloy educated. With a heat input of 170,000 joules / cm (where the welding current is 300A, the arc voltage is 30 V and the welding speed 32 min / min) the welding of the Seam joint carried out about 1000 mm behind it, with a feed margin of 8 mm being kept free will. This welding heat gives the welded joint a normalized structure, thereby largely avoiding brittleness.

For comparison purposes, on the other hand, a weld with a heat input of 170,000 joules / cm carried out. 2 mm V-notch impact tests are carried out on both welded joints. The comparison results are summarized in Table H. As in Example 1, the fracture transition temperature is lower according to the invention in comparison with the customary process. It can be seen that the notched impact strength the weld joint produced according to the invention is excellent

Tabel Welding process ( 11th kteristic
(kpm) values
( ⁰ Q Ver according to the invention
travel Charal
⁰ Q 6.3
1.4 -17
16 Usual procedure ... 16
70

Remarks:

vTs fracture transition temperature, vEo absorbed energy at 0 ⁰ C, v7 \ ₅ temperature at which the absorbed energy becomes 2.07 kpm.

Example 3

-75
9

Remarks:

vTs fracture transition temperature,
vEo absorbed energy at 0 "C,
vT _K temperature at which the absorbed energy becomes 2.07 kpm.

Example 2

Steel plates with a tensile strength of 60 kg / mm ¹ and a thickness of 45 mm (and with a composition as indicated in Table III under Test No. 2) are first compared in such a way that one Form a round joint. They are welded in a vertical position using a gas-shielded arc welding method. A steel alloy is applied to a thickness of 4 mm on each seam flank at a welding speed of 75 mm / min, using a 4% Ni electrode wire with a diameter of 0.8 mm kp / mm ¹ and a thickness of 38 mm (Test No. 3), steel plates with a strength of 60 kp / mm ² and a thickness of 38 mm (Test No. 4) and steel plates with a strength of 60 kp / mm * and a thickness of 45 mm are used as samples. The respective chemical compositions and the tensile shafts are summarized in Table III. A high-impact metal layer is first applied to each seam in a cross-section with a rise rate of 17 to 20 mm / mhi, using a!

4% N: ckel electrode wire with a diameter of 1.2 mm (see Table IV), whereby ad a gas-shielded arc welding process in a vertical position. Then eh Gas-shielded arc welding in the way through

Guided so that the feed margin is 10 mm In this way, a weld is made by the heat of welding at the time of ah After welding, the weld joint is given a normalized structure so that it hurts walking is free from brittleness

The following welding conditions are e.g. applied to steel plates with a thickness of 38 mm and a tensile strength of 50kp / mm * (test no.?

509508/1!

ίο

a) Welding the impact-resistant steel alloy onto the seam flanks of the steel plates:
COj arc welding, 150 A, 22 V, welding speed 20 mm / min; Electrode oscillation amplitude 35 mm, oscillation speed 6 mm / s; Flow rate 20 l / min; Clearance 7 mm;

b) Butt welding of the seam joint:
COg arc welding, 300 A, 30 V; Welding speed 35 mm / min; Amplitude of electrode oscillation 32 mm, oscillation speed 10 mm / s; Flow rate 20 l / min; 10 mm clearance.

The properties of the manufactured according to the invention Welded joints according to tests 3, 4 and 5 are shown in FIG. 12, which is explained on p. 11.

Example 4

This example illustrates the second embodiment of the invention, when carried out the applied Metal quenched immediately after solidification and the steel plate near this metal using water cooling nozzles that dispense water at the time of Application of a high notch impact resistant steel alloy spray so that a quenched structure is achieved in the weld joint. Afterward butt welding is carried out between the applied metal layers. The welding connection is annealed by the welding heat at this point, so that a quenched and Annealed structure is produced to prevent bond breakage.

A high-strength steel with a strength of up to 80 kg / mm ² , as listed in Table III, is processed into a steel plate with a thickness of up to 50 mm. This plate is used as a Protx. 50 mm thick test plates with a tensile strength of 80 kp / mm ^a are z. B. held under the following welding and water cooling conditions (test no. T):

a) Welding the impact-resistant steel alloy onto the seam flanks of the steel plates:
COg arc welding, 300A, 27 V, welding speed 27 mm / min; Electrode oscillation amplitude 46 mm, oscillation speed 10 mm / s; Flow rate 20 l / min: margin 13 mm;

b) water cooling:

Nozzle position 45 mm below the melting zone; 2 nozzles with an inner diameter in front 12 mm each on the front and back; Cooling water volume through each nozzle 5 l / min.

c) Butt welding of the seam joint:
COy arc welding, 300A, 30V, welding speed 39 mm / min; Electrode oscillation amplitude 46 mm, oscillation speed 10 mm / s; Flow rate 20 l / min; 9 mm clearance.

Subsequently, the respective impact strength properties the weld joint tested; the results are similar to those of FIG. 12.

Tabel

C. Si Mn Chemical composition
(%) S. Cu Cr Mon Ni V Train ften
train
firm
speed Test-
No. Steel robe P. sheep
Stretch
border kp /
well· 0.11 0.28 0.81 0.014 0.31 O4O 0.48 0.87 0.05 kp /
mm ¹ 32 mm thick, tensile strength 0.16 0.36 1.39 0.012 0.015 - - 0.11 0.19 0.05 88.0 1 80 kp / mm * ....
45 mm thick, tensile strength 0.19 0.40 1.41 0.019 0.015 - - - - - 83.9 65.4 2 60 kp / mm ¹
38 mm thick, tensile strength 0.14 0.45 1.39 0.027 0.015 - - - - 0.07 55.2 54.5 3 speed 50 kp / mm ² ....
38 mm thick, tensile strength 0.17 0.32 1.43 0.017 0.017 - - - 0.21 0.07 33.9 67.2 4. « 60 kp / mm *
45 mm thick, tensile strength 0.11 03 0.79 0.027 0.010 0.02 0.42 0.47 Ul 0.03 48.1 63.7 5 60 kp / mm *
40 mm thick, tensile strength 0.13 0.37 0.77 0.013 0.023 03 0.36 0.44 0.71 0.05 52.9 74.4 6th speed 70 kp / mm *
50 mm thick, tensile strength 0.11 0.27 0.78 0.017 0.013 0.04 0.37 0.37 1.02 0.03 64.6 84.5 7th 80 kp / mm *
35 mm thick, tensile strength 0.10 0 ^ 2 0.80 0.016 0.008 0.03 0.32 0.39 0.35 0.03 73.1 72.9 9 speed 70 kp / mm *
35 now thick, tensile strength 0.012 64.8 7 (U 10 speed 70 kp / mm * - 63.4

Table IV

12th

Electrode wire

Si Mn Chemical composition S. Ni Cr Mon I ^v Ti C. 0.35 1.85 P. 0.007 4.95 0.15 0.40 _ 0.01 0.07 0.62 1.50 0.011 0.010 3.67 - 0.25 - 0.01 0.07 0.57 1.72 0.013 0.012 3.45 0.45 0.48 - 0.03 0.08 0.60 1.43 0.007 0.008 2.97 - - 0.02 0.03 0.07 0.008

Test no.

A B C D

2,4,5,8 6,7,9,10

For this purpose 2 sheets of drawings

Claims (4)

1 2 steel plate has excellent notched impact strength claims: the notched impact strength is noticeably reduced. Under the term »sweat bond a 1. Procedure for the arc joint zone on the steel plate in a very narrow area welding of high-strength steels, low temperature 5 around the Scfainelzlinie in part of the heat Steels and low-alloy steels can be understood by stump-affected zone. Appearance seam, characterized in that the reduction in notched impact strength in one first on each seam flank as a buffer layer such a zone is generally called a high impact joint Steel alloy (5, 6) denotes brittleness. welds and then the seam joint with a dem io Base material adapted filler material (7) to an increase in the welding heat supplied. is fully welded. Especially if the shape of the weld 2. The method according to claim 1, characterized or weld seam has a discontinuity - beizeichnet, that when surfacing the seam, for example, as a result of an undercut, a manflank the weld in known penetration, a weld crack or a Slag inclusions are quenched by jets of water, on or in the vicinity (Fig. 8). the sweat bond - adds up by one 3. The method according to claim 1 or 2, thereby causing such welding effect to the characterized in that the seam joint in the protective gas lowering the notched impact strength in the welding arc process with increasing, by sliding ao bond, so that the probability is even greater shoes (10) forcibly formed weld pool (17) is full that em brittle fracture occurs. is welded (Figs. 4 and 5). Some attempts have already been made 4. Application welding electrode to carry out to avoid this fragility of the weld bond, of the method according to claims 1, 2 or 3, for example 1. by welding with reduced characterized in that the electrode from 35 welding heat supply, which, however, at the expense of an alloy of the following composition (%) welding productivity, 2. in the case of a normal: sized or rolled steel by heating the welded part by means of a gas flame on a 0.05 to 0.16 C, temperature above the A c _s transition point 0.30 to 0.80 Si, 30 (above about 900 ⁰ C) after welding, so 0.80 to 2.50 Mn, so that the toughness can adjust itself again, and 3. 2.50 to 10.00 Ni, by a measure that causes the steel plate Contains 0.01 to 0.10 Al, Ti, V, Nb, Zr, more than 3.5% JVi. However, each diminishes Remainder Fe. these measures increase welding productivity 35 the cost of the steel plates or limits the art