FR2492710A1 - Flux compsn. for flux-cored welding wire, esp. for steels - contains rutile concentrate, ferro:manganese, ferro:silicon, fluoro:silicate, magnesite, electro:corundum and iron powder - Google Patents

Abstract

Flux compsn. for flux-cored welding wire contains (by wt.) 20-53% rutile concentrate, 10-22.8% ferromanganese, 1.3-6% ferrosilicon, 1-5% sodium fluosilicate, 1.3-10% calcined magnesite, 1.6-7.5% electrocorundum, balance Fe powder. The flux-cored wire contg. the compsn. is also claimed. Flux-cored wires were produced with dia. of 1.6mm and steel sheaths comprising 83% of the wt. The flux compsns. used were (by wt.):(A)20% rubile concentrate, 10% ferromanganese, 1.30%ferrosilicon, 1.0% sodium fluosilicate, 1.3% calcined magnesite, 1.6% electrocorundum, 64.0% Fe powder; (B) 33.2% rutile, 12.5% ferromagnanese, 2.0% ferrosilicon, 2.1% Na fluosilicate, 5.6% calcined magnesite, 4.1% electrocorundum, 40.5% Fe powder; (c)46.5% rutile, 15.0% ferromanganese, 2.6% ferrosilicon, 3.3%Na fluosilicate, 10.0% calcined magnesite, 6.7% electrocorundum, and 15.9% Fe powder. The compsn. is esp. for wires used in (semi)automatic gas-shielded welding and surfacing of steel. The welding properties of the wire are improved so that the hydrogen and oxygen contents of resulting welds are minimised, preventing formation of welds and non-metallic inclusions. Welding efficiency is increased as the slag formed has lower fluidity.

Description

 The present invention relates to arc welding materials and in particular relates to a charge for powdered wires used for welding and reloading of steels under protective gas.

 The invention is particularly applicable to powdered wires intended for automatic and semi-automatic welding carried out in any position in space.

Filler compositions are known for powdered wires intended for welding and recharging under carbon dioxide gas, of steels in any position in space, these wires being in the form of a steel sheath filled with a powdered load. , the latter serving as a core for said wires. The best technological welding properties are those of powdered wires whose core contains,% by weight
silico-manganese ................ 10 to 25
ferro-manganese ................ 1 to 7
iron powder .................., 2 to 40
sodium fluoride .............. 0.5 to 3
potassium silicate ........... 0.5 to 3
titanium dioxide ............... 30 to 60 aluminum magnesium alloy ..... 1 to 7
manganese oxide .............. 3 to 10
aluminum powder .............. 0.5 to 5.0 (see USA patent N 3818178, cl. 219-146, published on June 18, 74).

 The presence, in said filler, of aluminum and magnesium which, when oxidized, form a series of oxides makes it possible to obtain, when welding with a wire having a core constituted by said filler, a slag having good properties physico-chemical, which ensures good formation of the metal of the weld. However, in this case, the aluminum passes into the metal of the weld partially in the form of nitride, which produces a considerable displacement of the threshold of brittleness when cold from the metal towards the high temperature range. Also, the wire, the core of which is constituted by the load which has just been described, is of limited use.

We also know compsotions of loads of powdered yarns whose threshold of brittleness when cold is located in the area of low temperatures (-20 C). It has been found that the best technological properties of welding and reloading under carbon dioxide, of steels in any position in space are those of the wires, the core of which is constituted as follows, $ 'by weight:
rutile concentrate ~ 53.4 manganese dioxide ee 4.4
silicon dioxide ............. 3.0
sodium oxide, - ......... 3.0
magnetite 9 6.0
ferro-manganese ................. 13.0
ferro-silicon .................. 12.0
iron powder * the rest (see USA patent N 3800120, cl. 219-146).

 However, when the welding is carried out using the wire whose core has the composition described, it is found that the metal of the welding has a high content of oxygen (0.09 No by weight) and hydrogen (10 to 12 cm3 per 100 g of reloading metal) which reduces the tudêdimetal weld ability to resist the formation of hot cracks; as well as its resilience in the field of low temperatures. To obtain a rapid crystallization of the welding slag which is formed during the melting of the powdered wire, as well as to improve the formation of the metal of the weld, a considerable quantity of silicon is introduced into the charge. The content of the metal of rechargemoeitensilici reached 0.8% by weight, which has an unfavorable influence on its plastic properties.

 The invention therefore relates to a filler for powdered wires intended for the welding and reloading of steels in a gaseous atmosphere, which would allow, thanks to qualitative and quantitative modifications of its composition, to communicate properties to the powdered wire. improved welding technology, as well as minimizing the amounts of oxygen and hydrogen in the weld metal, giving the metal high mechanical properties over a wide range of temperatures.

This problem is solved by the fact that the charge for powdered wires intended for welding and searching for steels under protective gas, of the type containing a rutile concentrate, ferro-manganese, ferro-silicon and an iron powder, is characterized, according to the invention in that said ingredients, it comprises sodium fluosilicate, annealed magnesite and electrocorundum or artificial corundum, the proportions of the components of said filler being as follows,% by weight
rutile concentrate .............. 20 to 53
ferro-manganese .................. 10 to 22.8
ferro-silicon ................... 1.3 to 6
sodium fluosilicate ........... 1 to 5
annealed magnesite ................ 1.3 to 10
electrocorundum .................. 1.6 to 7.5
iron powder .................... the rest
The introduction of rutile concentrate into the charge in the proportions indicated ensures the stability of the arc and good formation of the metal of the weld.

 The authors of the invention have found that when the content of rutile concentrate in the proposed charge is less than the lower limit mentioned, there is a marked deterioration in the stability of the arc, causing the metal to spray. electrode.

 By spraying the mazai of the electrode is meant the scattering of the drops formed by the wire. powdered fondant during welding.

In the case of exceeding the uccriber limit, hi occurs a phenomenon of delay in the melting of the core of the powdered wire relative to the rate of melting of the steel sheath of the said wire, which leads to an increase. , in the weld metal, non-metallic inclusions in the form of non-molten particles of the core, ultimately causing a significant loss of the -ua.'ites of the deposited metal
The amounts of ferro-manganese and ferrosilicon were chosen so as to ensure high mechanical properties for the metal of the weld. The indicated quantities of these elements in the proposed charge ensure the formation, in the metal of the weld, of fen # silicates — manganese with low melting points, which coagulate easily and rise to the surface. The metallic inclusions remaining in the metal have a round shape.

All this has a favorable influence on the resilience of the weld metal.

 When the quantities of fervoamanganese and ferresilicon are below the limits indicated, pores appear in the metal of the weld. Amounts of these elements greater than the recommended upper limit cause a significant increase in strength but a decrease in the plasticity of the metal of the weld.

 During welding, a large amount of hydrogen is present in the arc area. Now, it is known that hydrogen dissolving in metal at high temperatures is released from it during crystallization.

 Since the rate of release of hydrogen is not increased, pores are formed in the metal and a large amount of hydrogen remains which exerts an unfavorable influence on the mechanical properties of the metal of the weld. To prevent the dissolution of Hydrogen in the metal of the weld, sodium fluosilicate is introduced into the composition of the proposed filler in the proportions indicated. When the latter is introduced in smaller quantities than the recommended lower limit, no result is obtained. Exceeding the proposed upper limit leads to a sudden deterioration in the stability of the arc and, consequently, to heavy spraying. metal from the electrode.

 The annealed magnesia is introduced into the charge in the proportions indicated to increase the basicity of the slag, which promotes, as is known, the elimination of the non-metallic inclusions of the weld metal as well as the reduction of the total oxygen content of the latter.

 It has been established by the authors of the invention that the introduction of quantities of annealed magnesite lower than the lower limit indicated does not give a result and that quantities greater than the upper limit recommended lead to considerable sputtering of the metal of the electrode given the decrease in the amount of oxygen in the drops, which leads to an increase in surface tension and an increase in the dimensions of the drops.

 To reduce the fluidity of the slag and to lower the content of non-metallic oxide inclusions in the weld, we introduce into the composition of the proposed charge of electrocorundum in the proportions indicated. The introduction of the latter in smaller quantities than the lower limit proposed leads to an increase in the fluidity of the slag, compromises the formation of welds which significantly reduces the yield of welding and increases the content of non-metallic oxide inclusions. Exceeding the upper limit results in a diSkiondion of the technological properties of the slag: the melting temperature thereof increases. During welding, there is a delay in the melting of the charge constituting the core of the powdered wire by compared to the fusion of its sheath, the metal of the weld is polluted by non-metallic inclusions.

 The invention will be better understood and other objects, details and adventures thereof will appear better in the light of the explanatory description which will follow of various embodiments given solely by way of nonlimiting examples.

 Example 1.

During the welding, powdered wires with a diameter of 1.6 mm were used (conventionally designated A,
B and C) whose core was made from a filler according to the invention. The steel sheath of each of the wires constituted 83% of the total weight of the wire and was composed as follows,% by weight: carbon 0.059 manganese 0.020; trace silicon; sulfur 0.010; phosphorus: 0.010.

 The welding of the steel samples was carried out in a vertical position by the semi-automatic direct current process of reverse polarity.

The welding regime was as follows
welding current ..... 200 A arc voltage 23 V.

 Carbon dioxide was used as the protective medium.

 The welding steel, 20 mm thick, had the following composition,% by weight: carbon 0.18; manganese 0.45; 0.20 silicon; sulfur 0.20; phosphorus 0.015; iron, the rest.

 The compositions of the various fillers used for the manufacture of the cores of the powdered threads are indicated in Table 7 below.

 Table 1.

Filler components Powdered wires for cores
ABC
Quantitative composition of
load for cores,% in
weight
Rutile concentrate 20.0 33.2 46.5 ferro-manganese 10.0 12.5 15.0 ferro-silicon 1.30 2.0 2.60 sodium fluosilicate 1.0 2.1 3.3 annealed magnesite 1.3 5.6 10.3
Table 1 continued.

Filler components Powdered wires for cores
ABC electrocorundum 1.6 4.1 6.7 iron powder 64.8 40.5 15.9
The metal of the welds obtained using the powdered wires provided with cores produced from the fillers having the indicated compositions has been subjected to mechanical tests relating to the resilience, the relative elongation and the temporary resistance to rupture or resistance to traction, as well as a physicochemical analysis aimed at determining the gas content (oxygen, nitrogen and hydrogen) in the metal for recharging.

 The mechanical tests of the metal of the welds were carried out by known methods.

 The contents of the reloading metal in oxygen, nitrogen and residual hydrogen were determined by the known method of vacuum fusion, and the content of diffusion hydrogen, in accordance with the international standard ISO 3690.

 To illustrate the advantages of powdered wires, the core of which was manufactured from the filler in accordance with the invention, the results of the mechanical tests of the weld metal as well as the comparative results of the physico-chemical analysis of the content metal for gas recharging compared to the results obtained using the known technical solution (US Patent No. 3800120) are given in Tables 2 and 3 below.

 Table 2.

Yarn in Resistan- Allon- Resilience powder this tempo (Charpy notch), J / cm2 powder powder when rela-
tif failure,% + 2O0C -200C -400C
MPa
A 494.9 289.1 112.8-122.6 51-56.8 34.3-41.2
B 539.0 296.0 137.3-173.6 62.8-114.7 55.9-83.3
C # 91.9 220.5 99-110.8 37.3 # I2 3493 = 36.3
Patent thread
USA N 3800 120 637.0 200.9 73.5-88.2 24.5-29.4 7.8-7.8
Table 3
Gas content,% in Total content in Powdered wire residual hydrogen weight
and hydrogen
scattered, cm / 100g
oxygen nitrogen hydrogen
A 0.058 0.012 5.5
B 0.036 0.008 3.5
C 0.044 0.007 4.0
Wire according to USA patent N 3800120 0.09 0.016 12.0
it appears from table 2 that the metal of the welds obtained using the powdered wires A, B and C has higher mechanical properties. metal tail of the welds produced using the powdered wire manufactured according to the patent USA n0 3800120.

 On the other hand, the yield of welding carried out with the use of said wires constitutes 2.4 to 3.8 kg / h, which is 1.5 to 2 times higher than the yield of welding with powdered wire produced according U.S. Patent No. 3800120.

 The powdered wires, the core of which is produced from the filler according to the invention, provides the weld metal with excellent formation and easy separation of the slag crust, as well as a high resistance to hot cracks and a low gas content.

 Example 2.

During the welding, 2.2 mm diameter powder wires were used (conventionally designated A,
B and C) whose core was made from a filler ^ according to the invention. The steel sheath of each of the wires constituted 80% of the total weight of the wire and had the following composition (% by weight): carbon 0.07; manganese 0.25; 0.10 silicon; sulfur 0.030; phosphorus 0.030.

 The welding of steel samples was carried out on a vertical plane (horizontal welding) by the semi-automated direct current process of reverse polarity.

The welding regime was as follows
welding current 350 A
arc voltage 27 V.

 Carbon dioxide was used as the protective medium.

 The welding steel, 20 mm thick, had the following composition,% by weight: carbon 0.18; manganese 0.45; 0.20 silicon; sulfur 0.020; phosphorus 0.015; iron, the rest.

 The composition of the filler from which the cores of said powdered yarns were made is given in Table 1 below.

 Table 1.

Filler components Powdered wire
for cores
ABC
Quantitative composition of the
filler for nuclei,% by weight concentrated rutile 30.0 38.5 47.0 ferro-manganese 17 9 5 20.0 22.5 ferro-silicon 2.0 4.0 6.0 sodium fluosilicate 1.5 3 , 2 5.0 annealed magnesite 2.0 6.0 10.0 electrocorundum 2.5 5.0 7.5 iron powder 44.5 23.3 2.0
The metal of the welds obtained using the powdered wires whose cores were made from the filler having the compositions mentioned was subjected to mechanical tests relating to the resilience, the relative elongation and the temporary resistance to rupture. , as well as a physico-chemical analysis aimed at determining the gas content of the recharging metal (oxygen, nitrogen, hydrogen).

 The mechanical tests of the metal of the welds were carried out by known methods.

 The content of the reloading metal in residual oxygen, nitrogen and hydrogen was determined by the known method of vacuum fusion, and the content of diffusion hydrogen according to the international standard ISO 3690.

 The results of the mechanical tests thus carried out are given in table 2 below.

 Table 2.

Wire in Resistance Elongation- resilience for temporarily, re- (in Charpy eye), 8: cm2
in the rup- lative, 5 '
ture, MPa + 2O0C -20 C -400C A 521.4 279.3 100.9-109.8 L4.1-52, O 19.6-34 # 3
B 558.6 286.2 122.6-135.3 63,748.6 34, 3-39.2
C 607.6 240.1 96.1-îoe, 0 41.249.0 17.6-29.4
To illustrate the advantages of powdered wires, the core of which is made from a filler in accordance with the invention, Table 3 below shows the results of the physicochemical analysis for determining the content of the metal of gas recharging, compared to the results obtained using the known technical solution (USA patent N 3800120).

 Table 3.

Powdered wire Gas content, 5 'in Total content in
residual hydrogen weight and
in diffused hydrogen,
cm3 / 1 OOg
oxygen nitrogen hydrogen
A 0.055 0.011 4.6
B 0.040 0.010 3.8
C 0.044 0.011 5.2
Patent thread
USA N 3800 120 0.09 0.016 12
It can be seen, by examining Tables 2 and 3, above that the powdered wires whose cores are produced from the filler in accordance with the invention make it possible to obtain weld metals having high mechanical qualities. Furthermore, said powdered wires provide the weld metal with excellent formation and easy separation of the slag crust, as well as a high resistance to hot cracking and a low gas content.

 The welding yield with the proposed powdered wire reaches 8 kg / h, which is 1.5 times higher than the welding yield using the powdered wire manufactured according to USA patent NO 3800120.

 Example 3.

During welding, 2.5 mm diameter powder wires were used (conventionally designated A,
B and C), the core of which was made from the filler according to the invention. The steel sheath of each of the wires constituted 70% of the total weight of the wire and had the following composition,% by weight: carbon 0.08, manganese 0.30; 0.12 silicon; sulfur 0.030; phosphorus 0.030.

 The welding of the steel samples was carried out in the low position by the semi-automatic direct current process of reverse polarity.

The welding regime applied was as follows
welding current ... 450 A arc voltage ~ 32 V.

 Carbon dioxide was used as the protective medium.

 The 20 mm thick weld steel had the following composition, 5 'by weight: 0.18 carbon; manganese 0.45; 0.20 silicon; sulfur 0.020; phosphorus 0.015; iron the rest.

 The composition of the filler from which the cores of said powdered yarns were made is given in Table 1 below.

 Table 1.

Ingredients of Filler Powder Wire for Cores
ABC
Quantitative composition of the
filler for nuclei,% by weight concentrated rutile 20.0 33.2 46.5 ferro-manganese 10.0 12.5 15.0 ferro-silicon 1.3 2.0 2.6 sodium fluosilicate 1.0 2 , 1 3.3 annealed magnesite 1.3 5.6 10.0 electrocorundo 1.6 4.1 6.7 iron powder 64.8 40.5 15.9
The metal of the welds obtained using the powdered wires A, B and C was subjected to mechanical tests relating to resilience, relative elongation and temporary resistance to rupture, as well as to a physico-chemical analysis aimed at to determine the gas content of the recharging metal (oxygen, nitrogen and hydrogen).

 The mechanical tests of the metal of the welds were carried out by known methods.

 The contents of the reloading metal in oxygen, zazou and residual hydrogen were determined by the known method of vacuum fusion, and the content of diffusion hydrogen, according to the international standard ISO 3690.

 The results of the mechanical tests carried out on the metal of the welds are given in table 2 below.

 Table 2.

Yarn in Resis- Allon- Resilience (Charpy notch), powder tance gement J / cl
tempo- relaw
raire tif, 5 '
to the
ruptu- + 200C -200C -400C
re, MPa
A 492.0 289.1 118.6-121.6 44.1-47.1 29.4-41.2
B 532.1 292.0 132.4-138.3 63.7-69.6 34.3-44.1
C 588.0 225.4 103.0-188.8 39.2-42.2 27.4-43.1
The gas content of the recharging metal is shown in Table 3 below.

 Table 3.

Powdered wire Gas content, 5 'in Total content in
residual hydrogen weight
and hydrogen
diffused, c 100 g
oxygen nitrogen hydrogen
A 0.050 0.010 5.0
B 0.034 0.008 3.6
C 0.041 0.012 4.1
Wire according to USA patent no.3800120 0.09 0.016 12
Table 2 above shows that the powdered wires, the cores of which are made from the filler according to the invention, make it possible to obtain weld metals characterized by high mechanical qualities.

 On the other hand, said wires provide the weld metal with excellent formation in the low position. Such welds have a high resistance to hot cracking and are distinguished by a low gas content.

 The welding yield reaches 15 kg / h. The linear speeds of welding by angle beads constitute 50 to 80 m / h, depending on the side of the right angle of the weld.

Example 4 (negative)
The welding was carried out essentially as described in Example 1, but a powdered wire was used for the welding, the core of which was made from a load consisting of ingredients introduced in quantities lower than their recommended lower limit. by the present invention, the diameter of this wire was 1.6 mm.

The steel sheath of the wire constituted 83% of the total weight of the wire and had the following composition: 5 'by weight carbon 0.06; manganese 0.23; 0.09 silicon; sulfur 0.020; phosphorus 0.020.

The applied welding regime was as follows
welding current 450 A
arc voltage .............. 36 V arc,
The composition of the charge of said powdered wire was as follows
rutile concentrate 19.5
ferro-manganese 9.8
ferro-silicon ..... 1.0
sodium fluosilicate 0.8
annealed magnesite 1,2
electrocosin I, 4
iron powder 4 the rest.

The mechanical tests to which the metal of the weld was subjected gave the results:
temporary breaking strength,
MPa ~~~~~~~~~~~~~~~~~~ 460.6
relative elongation, 5 '235.2
resilience (Charpy notch) d / cm2
at + 200C 70.6 - 73.5
at -200C ............ 19.6 - 22.5
at - 40 C ........... 11.8-14.7.

 The results cited above show that the welding carried out using powdered wire, the load of which with the composition indicated in this example gives the metal of the weld unsatisfactory mechanical qualities, the metal is more subject to the formation of pores and cracks. On the other hand, the stability of the arc degrades and the sputtering of the metal of the electrode increases.

Example 5 (negative)
Welding was carried out as described in Example 3, but a powdered wire was used for welding, the core of which was prepared from a filler, most of the ingredients of which had been introduced in quantities greater than their upper limits. recommended by the present invention. The wire diameter was 2.5 mm.

The steel sheath of the wire constituted 70% of the pea: carbon O, 08; manganese 0.30; 0.12 silicon; sulfur 0.030; phosphorus 0.030.

Welding regime
welding current ........ 450 At arc voltage ......., ..,. 32 V,
The composition of the load of the wire considered being as follows
rutile concentrate. 47.0
ferro-manganese. ...... 23.0
ferro-silicon ....... 6.2
sodium fluosilicate ....... 5.2 annealed magnesite * @. 10.2
electrocorundum ........ 7.7
iron powder ....... the rest
Below are given the results of the mechanical tests that were made to the weld metal
temporary breaking strength, MPa ............ relative elongation,% ...... 19.5
resilience (Charpy notch) J / cm? ::
at + 200C 78.4-90.2 at -20 C ~ 16.7-19.6
at -400C 10.8-12.7
As can be seen, when the ingredients of the filler constituting the core of the powder wire are introduced in proportions exceeding the recommended upper limit, there is a deterioration in the technological properties of welding the wire. The atomization of the metal of the electrode increases greatly, the formation of the weld becomes poor and the plastic characteristics of the latter drop.

 Of course, the invention is in no way limited to the embodiment described which has been given only by way of example. In particular, it includes all the means constituting technical equivalents of the means described, as well as their combinations if these are executed according to the spirit and implemented in the context of protection as claimed.

Claims (2)

 1. Filler for powdered welding wire intended for welding and reloading of steels under protective gas, of the type containing a rutile concentrate, ferromanganese, ferro-silicon and an iron powder, characterized in that it further includes sodium fluosilicate, annealed magnesite and electrocorundum.  2. Filler for powder welding wire according to claim 1, characterized in that it contains% by weight:  rutile concentrate ..... 20 to 53  ferro-manganese ...... 10 to 22.8  ferro-silicon ................. 1.3 to 6  sodium fluosilicate 1 to 5  annealed magnesite 1.3 to 10  electrocorundum ........ 1.6 to 7.5  iron powder .......... the rest.