DE2410878A1 - FUEL WIRE ELECTRODE FOR AUTOGENIC ELECTRIC ARC WELDING - Google Patents

Description

4-9 312 - Dr.ϊ

Applicant: Kobe Steel, Ltd., 3-18, 1-Chome, Wakinohama-Cho, ! "ukiai-ku, Kobe (Japan)

Cored wire electrode for the autogenous electric liclitbogeitschv / eißen

The invention relates to a filler wire electrode for autogenous Elektx'o arc welding; it particularly concerns one Consuming, uninterrupted, tubular cored wire welding electrode, which contains a metal powder and slag forming agent in its core.

Nowadays the autogenous electric arc welding is widely employed for welding Flußstahlen and of high strength steels of 50 kg / MSP Kiasse. The increasing demand for welding of this type has led to recent attempts to produce welding wires which allow the production of a weld metal with excellent impact strength. However, with conventional welding wires or electrodes, there is an important problem that needs to be solved .; If the base metal to be welded contains large amounts of vanadium, niobium, phosphorus, sulfur and carbon, the elements are necessarily introduced into the deposit (deposit metal) because of the high tendency to base metal thinning in the case of autogenous electric arc welding.

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which means that the impact strength of the sweat is good in the frozen state is reduced or the desired Impact strength is not regained even if this is subjected to a subsequent heat treatment.

One of many attempts that have been made to solve this problem is in the published Japanese Patent application 22 644/1965 described in a Welding wire is used that contains a limited amount of deoxidizing metals or certain additional amounts of Contains Mo, Ti, Al, Zr, V, ITi and the like for the wire. However, this attempt had limited success with respect to the improvement of the notched impact strength of the weld metal or even led to a decrease in impact strength. This is particularly evident from the fact that in comparison to the other Schv / e.i ßverfahron for autogenous electric arc welding a large amount of heat is supplied and

it is a single-layer welding process. In particular is the heat input for manual welding or CCU gas welding at most 50,000 joules / cm and the supply of heat with concealed arc welding is 100,000 joules / cm, while the heat supply with oxy-fuel electric arc welding 60 COO to 500,000 joules / cm. In addition, the other welding processes, for example the Manual welding, CO ^ gas welding, concealed arc welding and the like, mostly a multi-layer welding method applied, whereby the metals (weld metal) deposited in one pass are subject to the influence of heat in the next Passage is exposed to the applied metal layer, which leads to a grain refinement of the structure of the deposited metals (of the weld metal) leads. In contrast, the autogenous electric arc welding in most cases a single deposited metal layer (weld metal layer), in which the above-mentioned heat influence of the superposed deposited metal layers does not occur, so that a typical cast joint remains.

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One has therefore striven for a long time to use the legacy Oxy-fuel electric light bulb welding occurring in steels To avoid strength problems "

The main aim of the invention is therefore to provide an uninterrupted filler wire welding electrode that can be used for autogenous Electric arc welding of steels is suitable and delivers a weld metal with an improved notch lock, Zi ^ i It is also of the invention to provide a continuous felling wire welding electrode indicate which is suitable for use in oxy-fuel electric arc welding of steels and over a wide range of applications including welding of steels, i.e. from mild steels to low-alloy high-strength steels Steels of the 50 kg / iraa class, can be used.

According to a first aspect, the present invention relates to an uninterrupted filler wire welding electrode with a tubular jacket made of strip steel and a core which contains metal powder and slag forming agents, the amount of said powdery masses being within the range from 1.5 to 60% by weight _? based on the total weight of the cored wire welding electrode, while the cored wire welding electrode in its entirety consists of no more than 0.3% by weight of carbon, 0.8 to 3.0 % by weight of manganese, 0.1 to 1 , 0 wt .-% silicon, 0.05 to 0.8 wt .-% molybdenum, 0.001 to 0.3 wt .-% titanium and the remainder in the v / es ent borrowed from iron with the exception of the slag formers.

According to a further aspect, the present invention relates to a continuous filler wire welding electrode of the type indicated above Composition which, in its core surrounded by the jacket, contains at least titanium, which is in the form of a powder.

According to a third aspect, the present invention relates a continuous flux-cored welding electrode of the above

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given composition, which also, if necessary, not more than 6 wt .-; o nickel, not more than 10 wt .- 5i chromium, not more than 1.5 wt .-% of one or more of the elements Aluuiniuia, zirconium - and contains vanadium and 0.001 to 0.005 percent boron.

The invention is described below with reference to the enclosed Drawing explained in more detail. The latter shows three cross sections through filler wire welding electrodes according to the invention.

The present invention is the result of various experimental studies on the above problems and it is based on the fact that it has been found that (i) the improvement in the impact strength of the weld metal at autogenous electric arc welding necessarily the Achievement of a grain refinement as well as an annealing (Spherical annealing) of the crystal grains, (ii) this grain refinement and annealing or spheroidizing the crystal grains for its part, it means that Kangan and silicon only contain very small amounts in the weld metal (deposit metal) are; the titanium contained therein should be microscopically uniformly dispersed in the debris; and (iii) the improvements in internal cracking in the weld metal and in the smoothness of the bead surfaces require that the type of titanium contained in the electrode with regard to the arc melting properties the steels must be specified. The overwhelming advantage of having a very small length of titanium the improvement of the notched impact strength of the deposit metals (of the weld metal) in oxy-fuel electric arc welding can point to the difference between autogenous electric arc welding and the other welding processes, which are recurrent is that (i) in oxy-fuel electric arc welding a large amount of heat is supplied, resulting in an extremely slow cooling and solidification rate.

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the ability of the material to be melted, (ii) the autogenous electrical arc welding in most fillings instead of a year-round welding process Such an Einßchiclr!; en-Schv / eißvei \ frihr?: n represents, in which the in a liurch;? - ang applied Schv; si £ - well not the influence of the Vfärne in the subsequent näsn major chip n ^ applied metal layer is subject, and (iii) in the autogenous Elel-ctro arc ^ cbv / eiiss the hydrogen and Oxygen levels in the sweat are good (order metal) relatively are lower.

The facts that were found on the basis of the above-mentioned experiments also include the fact that in the case of autogenous electric arc welding a so-called filler seam welding electrode with a continuous tubular dumbbell, in which powdery preparations such as flux, are enclosed , results in better arc stability and a better beading appearance than a bare (not uncovered) electrode (solid dx'ahtslektrode) as well as the fact that in the fill-wire welding electrode, the titanium powder-containing electrode for the shear material (deposit metal) a better Kerbßchlagzähigkeit \ ^r erleiht as 'containing such JDlelrtrod' n that no TitanpulYer. But even in the gut, if the jitari is alternatively contained in the mantle itself, certain improvements with regard to the kerbschiagsäliigkeit are to be expected. It has also been found that better results can be obtained from the same green donor described in relation to titanium, if boron in the form of powdery ferroboron is contained within the jacket of the electrode.

The addition of manganese and silicon to the filler wire electrode is necessary to achieve optimum strength, ductility and improved notched impact strength of the welded material. To this end, in a dan slopes should Luenge within the range of 0.8 to 5.0 wt .- ^ and silicon in an amount of 0.1 to 1.0 Gev /.-? S vox be ⁱ hands. I.I with a manganese content of no more than 0.8 weight-νό and with a ßili-

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cium content of not more than 0.1 wt. the advantages described above are not achieved. A manganese content of more than 3 _} O Ger /, -% leads to an increase in the hardness of the shredded material as well as to a? low segregation, which leads to internal cracking in steels. If the silicon is present in a mence of more than 1.0% by weight, the hardness of the welded material increases with simultaneous cracking, especially when viewed from the side. A very low molybdenum content in the weld (deposited metal) leads to a grain refinement which has an advantageous influence on the impact strength of the weld metal. If molybdenum is present in the electrode in an amount of less than the lower C limit given above (0.05% by weight), then this will be. Advantage not achieved, while if the molybdenum content is above the upper limit given above (0.8 wt. - £ 5), the notched impact strength] -: as well as the resistance to crack formation, g of the weld metal decreases. The preferred hollybdenum content is 0.1 to 0.8% by weight. The carbon content should not exceed 0.3 Ge? /. -% . The lower the carbon content, the better the impact strength of the weld metal. At a carbon content of more than 0.3 wt .- / S, however, the notched impact strength of the welded material decreases and cracks form. A carbon content xon not more than 0.3% by weight νό is tolerable from the standpoint of practical use.

The above items can also be used in the coat of the Cored wire electrodes can be included and also provide advantages of up to 2m to a certain extent. However, these items should preferably within the jacket in the form of an alloy powder, such as z.3. in the form of Ferrosiliciuia, Ferroraolybdenum, Ferromanganese and the like. Titan plays one important role in the cored wire electrode according to the invention, This is evident from the more detailed description below.

The titanium contained in the cored wire vision electrode should in the form of powdered. Ferrotitanium, powdered titanium, in shape

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of powdered titanium alloys and the like. Are present if there is is admitted. Table I below shows the chemical Composition of bare electrodes (diameter 2> 4 mm) For use when welding a 25 mm thick mild steel plate when using the oxy-fuel electric arc welding method. The following table II shows the mechanical properties of the weld metal obtained in this way (the Order metals) specified.

Table I.

Chemical composition of the examined naked (non-covered) electrode

Wire- -Type O C. 0 Si Mn 0 , 26 0 Ti S1 O , 07 0 , 52 1.83 0 , 26 0 , 03 S2 O , 07 O , 4-9 1.69 0 , 25 O , 05 S3 , 07 , 69 1.78 , 07 Table II

Mechanical properties of the 'use of bare (uncovered) Electrodes of weld metal obtained (deposit metals)

Wire type stretching tensile strength elongation constriction notched impact _{limit 2} tion toughness be: (kg / mm) (kg / mm) (>&)(#) O ⁰ C at a

2V side notchc (iakg)

51 33.1 51.3 27 62 4.1

52 36.3 54.1 25 61 4.2

53 35.4 52.9 26 63 4.4

In contrast, the cored wire welding electrode according to the invention gives which contains ferro titan within its jacket, the weld metal has a high level of carbon fiber toughness, as can be seen from the Ausfülirungsforinen described below emerges. These

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Differences are due to the fact that im In the case of the use of wire electrodes from the wire itself an arc is generated, so that the contained therein Titanium is exposed to the arc and heated to an extremely high temperature. The affinity of titanium for it Oxygen is greater than that of manganese or silicon, which causes titanium to be stronger at a high temperature Is oxidized to a degree as manganese or silicon. If there is oxidized material in the weld metal during autogenous electric arc welding Titanium, i.e. titanium oxide, is present, the result is a weld metal with a needle structure, which gives it its notched impact strength is reduced.

On the other hand, when the filler wire electrode containing ferrotitanium in the powdery flux is used primarily an arc is generated from its jacket so that the ferrotitanium is not exposed to high temperatures, from which a lower degree of oxidation results

It follows that when using a filler wire electrode there is no adverse effect due to titanium oxide, but that a weld deposit is obtained which has the advantages as were to be expected with titanium. in the Remaining it should be noted that among the cored wire electrodes themselves those electrodes, the titanium powder within their jacket contain better results than those containing titanium in the shell itself, as in the above case when using bare (uncovered) electrodes. By However, those electrodes that contain titanium in their sheath themselves can have a notched impact strength to a certain extent Grade to be improved.

It follows that the titanium contained in the electrode are in the form of powdery ferrotitanium and from the shell should be surrounded. However, the presence of ferrotitanium alone within the shell of an electrode does not lead to Achieving the desired advantages of the titanium-containing filler

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wire welding electrode. In other words, it is important that the titanium content in the electrode is very low, ie the titanium content should be limited to a value within the range from 0.001 to 0.3 % with the simultaneous presence of manganese, silicite and molybdenum in an electrode according to the invention. This is due to the fact that the effectiveness of titanium would be subject to the influence of manganese, silicon and molybdenum if they were contained together. In detail, this means that if the titanium content exceeds 0.3%, the desired advantages are not obtained, but instead the brittleness and tendency to ice formation increase. Such an adverse influence is particularly evident when the titanium content is more than 0.07%, so that the titanium content should be kept below 0.07% for best results. On the other hand, if the titanium content is less than 0.001%, the desired effects will not be obtained. Accordingly, the titanium content should exceed 0.001%.

For the same reasons given above in the case of titanium, boron should be used in amounts within the range of 0.001 to 0.05% in the form of ferroboron powder. The amount one or more of the elements Al, Zr and V should be within of the range of not more than 1.5%. This range was determined in the various experiments mentioned above A combination of Al, Zr, Ni and Cr in the required amount Amount gives the best results. When Al, Zr and V are contained in small amounts, the impact strength becomes of the weld deposit improved, while thenj when they are in large Quantities are present that reduce the impact strength of the weld metal as well as its ductility, at the same time cracking may occur.

In addition, the use of nickel and chromium increases the strength of the weld metal (deposit metal) increased, while at the same time the notched impact strength to a certain extent

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is improved, although excessive amounts of nickel and chromium lead to an undesirable increase in the strength of the weld metal with a simultaneous reduction in the bending properties of the weld metal. The nickel content should not be more than 6 % . If the nickel is in excess in the electrode, segregation of the molten material occurs in the weld metal, which causes cracks to form. The chromium content should not be more than 10% from the standpoint of the strength of the weld metal. As in the above cases, these elements can also be contained either in the shell or in the flux (core).

The flux components that are inside the shell of the electrode can be of the usual type, for example known slag formers, iron powder, alloy powder, Deoxidizers and the like. In oxy-fuel electric arc welding the amount of slag builders should be kept to a minimum. In other words, if Excessive amounts of slag formers are contained in the flux, a large amount of slag is generated in the Weld deposit (build-up metal), which makes the arc unstable, resulting in imperfect penetration of the weld leads. For this reason, the flux used according to the invention preferably and essentially contains iron powder, alloy powder and deoxidizer instead of a large amount of slagging agents

The cored wire welding electrode according to the invention is by no means limited to the electrode cross-sectional shapes shown in the accompanying drawing. The weight ratio of the powdery Compositions to your total weight of the electrode should preferably be within the range of 1.5: 100 to 60: 100.

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The invention is illustrated in more detail by the following examples, without, however, being restricted thereto.

example 1

A cored wire welding electrode was used which contained a total of 0.009 % carbon, 1.96 % manganese, 0.48 % silicon, 0.11 % molybdenum and 0.03% titanium, the titanium and silicon in the form of ferro-titanium and ferro-silicon were locked inside their cloak. This cored wire welding electrode had an outer diameter of 2.4 mm and was used for butt welding an I-shaped welding notch with a notch spacing of 18 mm in a high-strength steel of 50 kg / mm class and a thickness of 32 mm.

The base metal used contained 0.08% carbon, 1.36% manganese, 0.39% silicon, 0.016 % phosphorus and 0.022 % sulfur. The mechanical properties of the weld metal are given in Table III below.

Table III

Mechanical properties of the weld metal (deposit metal)

Yield strength Tensile strength ρ Elongation Constriction Notched impact (kg / mm2) ability (kg / mm) (%) tion (%) toughness at

O ⁰ C, 2V side notch (mkg)

38.7

59.2

24

60

7.3

Example 2

A filler wire electrode was used which contained a total of 0.09 % carbon, 1.82 % manganese, 0.64% silicon, 0.07% titanium, 0.28 % molybdenum and 0.004 % boron, the titanium, the silicon, that boron and manganese were enclosed in their mantle in the form of iron alloys · These

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The electrode had an outer diameter of 3.2 mm and was used for the autogenous electric arc welding of a mild steel plate with a thickness of 25 mm to produce a welded joint with a notch angle of 20 ° and a notch spacing of 10 mm. The base metal contained 0.16 % carbon, 0.69 % manganese, 0.21 % silicon, 0.027% phosphorus and 0.019 % sulfur.

The mechanical properties of the weld metal obtained in this way (deposit metal) are given in Table IV below.

Table IV
Mechanical properties of the weld metal

Yield strength Tensile strength _o Elongation Constriction Notched impact strength (kg / mnr) (kg / mnT) (%) at 0 ° C

(2V side notch). (mkg)

37.1

Example 3

57.1

28

63

8.7

A filler wire electrode was used which contained a total of 0.09 % carbon, 1.52% manganese, 0.39 % silicon, 0.01 % titanium, 0.61% molybdenum, the titanium, the manganese, the silicon and the Molybdenum in the form of powdered ferro-titanium, ferro-manganese, ferro-silicon and ferro-molybdenum were enclosed within the shell. This cored wire electrode had an outer diameter of 3 »2 mm and it was used for axitogenic electric arc welding with the formation of a weld joint with a notch angle of 20 ° and a notch spacing of 10 mm for a high-strength steel plate of the 50 kg / mm ^ class with a thickness of 32 mm used. The base metal contained 0.16 % carbon, 1.42 % manganese, 0.37 % silicon, and 0.02 % vanadium.

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The mechanical properties of the weld metal obtained in this way (build-up metal) are given in Table V below.

Table V
Mechanical properties of the 'weld metal

Yield strength Tensile strength _p Elongation Constriction Notched impact strength (kg / mm2) speed (kg / mnT) (%) tion (%) keif at O ⁰ C

(2V side notch |) (mkg)

44.2 62.5 26 61 8.9

The cross-sections of some of the IT-cored wire welding electrodes according to the invention are shown in the accompanying drawing (a, b and c).

Although the invention has been explained in more detail above with reference to preferred embodiments, it is clear to the person skilled in the art that it is in no way restricted thereto, but that these can be changed and modified in many respects without thereby departing from the scope of the present invention .

The phrase "autogenous electric arc welding" was used used for the English expression "Electro-Gas Arc Vielding", which also translates as "Electro-Gas Arc Welding" can be.

Patent claims:

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Claims (6)

Claims 1. Consuming, uninterrupted cored wire electrode with a tubular jacket made of strip steel and a powdery preparation surrounded by a metal powder and slag formers for the autogenous electric arc welding of steels of the type that includes mild steels up to high-strength steels of the 50 kg / mm class, the The amount of the powdery preparation is within the range from 1.5 "to 60% by weight, based on the total weight of the cored wire electrode, and the electrode as a whole consists of no more than 0.3% by weight of carbon, 0.8 to 3, 0 wt .-% manganese, 0.1 to 1.0 Grev7 .-% silicon, 0.05 to 0.8 wt .-% molybdenum, 0.001 to 0.3 wt .-% titanium and the remainder essentially of iron with the exception of the slag formers, characterized in that at least the {titanium among the metal components within the shell is in the form of a powder. 2. Consuming, uninterrupted cored wire electrode with a tubular jacket made of strip steel and a powdery preparation of metal powder and slag formers surrounded by it for autogenous electric arc welding of steels of the type that includes mild steels up to high-strength steels of the 50 kg / mm class, the amount of powdery preparation within the range from 1.5 to 60% by weight, based on the total weight of the cored wire electrode, characterized in that the cored wire electrode as a whole consists of not more than 0.3% by weight of carbon, 0.8 to 3.0 wt -.% manganese, 0.1 to 1.0 wt .- # silicon, 0.05 to 0.8 wt .-% molybdenum, 0.001 to 0.3 wt .-% iDitan 0.001 to 0 05% by weight of boron and, for the most part, of iron apart from the slag formers and that among the metal components at least the titanium and the boron are present in the form of a powder within the shell. 409837/0875 3. Consuming, uninterrupted cored wire electrode with a tubular jacket made of strip steel and a powdery preparation of metal powder and slag formers surrounded by it for autogenous electric arc welding of steels of the type that includes mild steels up to high-strength steels of the 50 kg / mm class, the amount of powdery preparation within the range of 1.5 to 60 wt .-%, based on the total weight of the filler wire electrode, characterized in that the filler wire electrode consists of not more than 0.3 wt .-% carbon, 0.8 to 3.0 wt% manganese, 0.1 to 1.0 wt% silicon, 0.05 to 0.8 wt% molybdenum, 0.001 to 0.3 wt % titanium, one or more of the elements listed below in the specified quantities (a) no more than 6 wt% nickel (b) no more than 10 wt% chromium (c) one or more of aluminum, zirconium and vanadium in an amount not more than 1.5% by weight and the remainder essentially of iron apart from the slag formers, whereby of the metal components at least the titanium is in the form of a powder within the shell. 4. Cored wire electrode according to claim 3 »characterized in that that it also contains from 0.001 to 0.05% by weight of boron; and that the boron is in addition to the titanium among the metal components is in the form of a powder within the shell. 5. filler wire electrode according to claim 1, characterized in that that their titanium content is within the range from 0.001 to 0.07% by weight, based on the total weight of the cored wire electrode, lies. 6. Cored wire electrode according to claim 2, characterized in that its titanium content is within the range of 0.001 to 0.07 wt.% _T based on the total weight of the cored wire electrode. 4098 3 7/0875 It Blank page