DE3031149A1 - 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

Powder Composition for Cored Wire Electrodes The present invention relates to a powder composition for cored wire electrodes for gas-shielded welding and inert gas deposition welding of steels and thus generally on welding materials for arc welding.

With the greatest benefit, this invention can be used in cored wire electrodes, which is intended for automatic and semi-automatic welding in all positions are to be used.

Some powder compositions for filler wire electrodes are known, which for C02 welding and C02 surfacing of steels in all positions are intended, consisting of a filled with powdery composition Steel jacket, the composition mentioned being the Electrode core represents. Cored wire electrodes in particular have better welding properties with a rolgender composition whose core is (in percent by weight): silicon manganese ............................... 10 to 25 Berry Mangan ............... ............................ 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 0.o ... 1 to 7 Dimanganese trioxide ...................... 3 to 10 aluminum powder .......................................... 0.5 to 5.0 ( see US-PS Er. 3818178).

Due to the presence of aluminum and magnesium in the mentioned Powder composition which, when oxidized, form a pure of oxides it is possible when welding with full-wire electrodes with one of the powder compositions mentioned manufactured electrode core the welding slag with good physical-chemical To maintain properties, whereby a good weld seam formation is guaranteed. The aluminum in the form of nitride goes partly into the weld seam material About what, as it is already known, the threshold value of the cold brittleness of the Welding material is shifted into the high temperature range. That's why the use of ll-wire electrodes, the cores of which are made from the recognized powder composition is manufactured, limited.

There are also powder compositions for cored wire electrodes known, whose cold brittleness threshold is in the delivery temperature range (-20 ° C).

better welding technological properties in C02 welding and C02 extrusion welding of steels in room-high positions have cored wire electrodes, whose core is made from the powder mixture of the following composition (in percent by weight): Rutile concentrate ................................ 53.4 Manganese dioxide ............. ...................... 4.4 silicon dioxide ................................. 3.0 sodium oxide ......... ........................... 3.0 Magnesite ....................................... 6.0 Ferromanganese ... ................................. 13.0 Ferrosilicon .................................. 12.0 Iron powder ........ ............................ remaining (5th U.S. Patent No. 3800120).

When welding with cored wire electrodes, the core of which consists of the mentioned Powder composition is prepared, however, it comes to a high content Oxygen (0.09 percent by weight) and hydrogen (10 to 12 cm3 per 100 g weld metal) in the weld seam material, which increases the resistance of the welded material to hot cracks and its notched impact strength is also reduced in the low temperature range. To the Speeding up the. Crystallization in the course of the melting of the oil wire electrode formed welding slag and also to improve the weld seam formation a significant amount of silicon was introduced into said powder composition. The content of the latter in the weld metal is 0.8 percent by weight, What also has a detrimental effect on the plastic properties of the weld metal.

The invention is based on the object of a powder mixture for cored wire electrodes for inert gas welding and inert gas deposition welding of steels to sharp which it is made possible by the qualitative and quantitative modification of their composition to give the cored wire electrodes improved welding technology properties, the water and oxygen content of the weld seam material to a minimum and thus this high mechanical properties in a wide Give temperature range.

The object set is achieved in that the powder composition for full-wire electrodes for gas-shielded welding and gas-shielded deposition welding of Steels, contain rutile concentrate, ferromanganese, rerrosilicon and iron powder, in addition, according to the invention, sodium hexafluorosilicate, burnt magnesia and It is particularly preferred that the constituents mentioned contained in the following ratio (in P.%) rutile concentrate ..................................... 20 to 53 ferromanganese .................................. 10 to 22.8 ferrosilicon ........................................ 1.3 to 6 sodium hexafluorosilicate .... ......................... 1 to 5 burnt magnesite .................................. 1.3 to 10 corundum ................................... 1.6 to 7.5 iron powder ....... .................................. remaining By the presence of rutile concentrate in the invention Powder composition for cored wire electrodes in the quantities mentioned, a stable burning of the Arc and a good weld seam formation guaranteed.

We found that lowering the content of the invention Powder composition of rutile concentrate below the lower limit mentioned is less advantageous because it increases the stability of the arc burning is strongly disturbed and a strong splash of electrode metal occurs.

Under the spray of electrode metal is here and below the splashing of drops of the flux-cored wire electrode, which has melted during welding to understand.

If the upper limit value is exceeded, the melting speed remains of the powder core of the full-wheel electrosis against that of its steel casing, whereby the content of the weld seam material in non-metal inclusions in the form of non-melted particles of the powder core and thus the properties can be significantly affected by weld metal.

The amount of ferro-manganese and berronilicon is such that it is high mechanical properties of the weld seam material are guaranteed. Both mentioned amounts of these ingredients in the powder composition according to the invention there is the formation of easily melting iron manganese silicates in the weld seam material, which easily coagulate and rise to the surface. Those in the weld seam material Remaining non-metallic inclusions are from runder bors. all of this affects the Eerb impact strength of the weld seam material cheap.

The lowering of the content of erromangan and ferrosilicon below the limits mentioned is due to the appearance of pores in the weld seam material unfavorable. The introduction of these ingredients in the amounts that correspond to the above Exceeding the limit value leads to a substantial increase in strength and a reduction in strength the ductility of the weld seam material.

During the welding process is located in the arc welding zone a large amount of hydrogen. It is common knowledge that hydrogen, which dissolves in the metal at high temperatures during the crystallization process out of this. Because the rate of elimination of hydrogen is not is high, pores are formed in the weld hydrogen and one remains large amount of hydrogen, which affects the mechanical properties of the weld seam material has a disadvantageous effect. ur prevention of hydrogen dissolution in the weld seam material is in the powder composition according to the invention in the mentioned amounts of sodium hexafluorosilicate introduced.

The introduction of the latter in an amount that the said lower Falls below the limit value, does not lead to a positive result. The transgression of the upper limit value leads to the deterioration of the stable burning of the arc and thus for strong spraying of electrode metal.

The burnt magnesite is in the specified amount in the powder composition introduced for full-wire electrodes to increase the basicity of the welding tubes, what, as known, the exemption of the weld material from Non-metal inclusions and also the lowering of its total oxygen content promotes, It was found by us that the lowering of the content of burned Magnesite in the powder composition according to the invention below the lower mentioned Limit value does not lead to a positive result, Exceeding the upper limit value drives to a substantial increase in the spraying of electrode metal, since the content the metal drop is lowered in oxygen, which leads to an increase in surface tension and leads to an increase in droplet size.

To reduce the liquid content of the welding slag and its content of the weld metal on non-metallic oxide inclusions is in the Errindungsgemeinschaft Powder composition introduced in the specified amount of electro corundum. The introduction of the latter in an amount that falls below the specified lower limit value, leads to an increase in the fluidity of the welding slag, to deterioration the formation of the weld seam, as a result of which the welding performance is greatly reduced, and also to increase the content of non-metallic oxide inclusions. The crossing the upper limit value leads to a deterioration in the manufacturing properties the tail slag - there is an increase in their melting point.

During the welding process there is a lag in the melting speed the powder composition from which the core of the cored wire electrode is made is to be recorded against the melting speed of the electrode jacket, what last In the end the contamination of the weld seam material by non-metallic inclusions.

Furthermore, the essence of the present invention is illustrated by the detailed description of the Ausfätirungsbeispiele explained.

Example 1 true to the welding process were full-wire electrodes with a diameter of 1.6 mm (conditionally referred to as A, B and C), their serine is produced from the powder composition obtained according to the invention. The steel jacket of the respective Fülldrahtelectrode was 33 percent by weight of the total mass of this electrode and had the following composition (in percent by weight) on: carbon - 0.05; Manganese - 0.020; Silicon - traces; Sulfur - 0.010; phosphorus - 0.010.

flas welding of bar specimens was carried out with their vertical position using the semi-automatic process with reverse polarity direct current carried out.

Welding parameters: welding current .............. 200 A arc voltage ..... 23 V carbon dioxide was used as a protective gas.

The steel to be welded with a thickness of 20 mm had the following Composition (in percent by weight): carbon - 0.18; Manganese - 0.45; silicon - 0.20; Sulfur - 0.020; Phosphorus - 0.015; remaining - iron.

The powder compositions that make up the cores of the cored wire electrodes are listed in Table 1.

Table 1 Components of the powder cored wire composition of the A B C electrode core Quantitative composition of the powder mixture of the Electrode core (in percent by weight) rutile concentrate 20.0 33.2 46.5 ferromanganese 10.0 12.5 15.0 Ferrosilicate 1.30 2.0 2.60 Sodium hexafluorosilicate 1.0 2.1 3.3 Burnt magnesite 1.3 5.6 10.0 Electro-corundum 1.6 4.1 6.7 Iron powder 64.6 40.5 15.9 The result of the application of the cored wire electrodes, whose cores are made from the powder mixture the specified composition are produced, the weld seam material obtained was mechanical tests to determine its notched impact strength, specific elongation and tensile strength, as well as a physico-chemical analysis for the determination the content of gases such as oxygen, nitrogen and hydrogen in the weld metal subjected.

The mechanical tests of the weld seam were increased carried out in accordance with the custody known per se.

The content of oxygen, nitrogen and the rest of the weld metal Hydrogen was by the known vacuum melting process, and its Content of diffusion hydrogen - according to the international standard ISO 3bgv determined.

To illustrate the advantages of the cored wire electrodes, their serine is produced from the powder composition according to the invention, are comparisons ichaergebniaae of the mechanical tests of the weld seam material, as well as comparative results the physical-chemical analysis to determine the gas content in the weld metal with analog achieved when using a known technical solution Results, cited (see U.S. Patent No. 3800120).

The stated results of the examinations carried out are in Tables 2 and 3 listed.

Table 2 Cored wire tensile specific notched impact strength electrode residual strength, cal strain (Charpy sample), kgm / cm2 kg / mm² tension,% +20 ° C -20 ° C -40 ° C A 50.5 29.5 11.5-12.5 5.2-5.8 3.4-4.2 B 55.0 30.2 14.0-17.7 6.4-11.7 5 , 7-8.5 C 60.4 22.5 10.1-11.3 3.8-4.2 3.5-3 ,? Cored wire electrode according to 65.0 20.5 7.5-9.0 2.5-3.0 0.8-0.8 U.S. Patent No.

5800120 Table 3 Full-wire electrodes, total gas content of remaining (in weight and diffusion hydrogen, percent) cm3 / 100 g oxygen Nitrogen hydrogen A 0.058 0.012 B 0.036 0.008 3.5 C 0, u44 0.007 4.0 iill wire electrode according to US-PS 0.09 0.016 12.0 No. 3800120 From Table 2 it can be seen that aer Welding seam material, which is produced using full-wire electrodes A, B and C obtained has higher mechanical properties than that using weld material obtained from cored wire electrodes made in accordance with U.S. Patent No. 3800120.

In addition, there is the efficiency of the welding process when using the full-wire electrodes mentioned at 2.4 to 3.8 kg / h, what that 1.5 to 2 times higher than the welding performance when using according to US-PS No. 3800120 is made of cored wire electrodes.

Through the filler wire electrodes, the serine of which is derived from the inventive Powder composition produced will be excellent weld formation as well as good separability of the slag coating, as well as high resistance against ice cracks and a low ias content achieved.

Example 2 During the welding process, fildrant electrodes used with a diameter of 2.2 mm (conditionally referred to as A, B and C), the core of which is produced from the powder composition obtained according to the invention is. The steel jacket of the respective cored wire electrode was 80 percent by weight of the total mass of this electrode and had the following composition (in percent by weight) on: carbon - 0.07; Manganese - 0.25; Silicon - 0.10; Sulfur - 0.030; phosphorus - 0.030.

The welding of steel specimens was carried out in a vertical plane (seam weld) using the semi-automatic process with reverse polarity direct current carried out.

Welding parameters: welding current .............. 350 A arc voltage ........ 27 V Carbon dioxide was used as the protective gas.

The steel to be welded with a thickness of 20 mm had the following Composition (in percent by weight): carbon - 0.18; Manganese - 0.45; silicon - 0.2Q; Sulfur - 0.020; Phosphorus - 0.015; remaining - iron.

The powder compositions from which the cores of the mentioned filler wire electrodes are listed in Table 1 below.

Table 1 Components of the powder cored wire composition of the electrode A B C of the core Quantitative composition of the powder mixture of the Electrode core (in percent by weight) Eutil concentrate 30.0 38.5 47.0 Ferromanganese 17.5 20.0 22.5 Ferrosilicon 2.0 4.0 6.0 Sodium hexafluorosilicate 1.5 3.2 5.0 calcined Magnesite 2.0 6.0 10.0 Electro-corundum 2.5 5.0 Iron powder 44.5 23.3 2.0 The through the application of the cored wire electrodes, the cores of which are made from the powder mixture mentioned Composition were made, the weld seam material obtained became mechanical Tests to determine its notched impact strength, specific elongation and Zerreißfestigeit, as well as a physical-chemical analysis to determine the Content of the weld metal in gases such as oxygen, nitrogen and hydrogen.

The mechanical tests of the weld seam material were measured carried out the per se known method.

ser content of the welded material of oxygen, nitrogen and the rest Hydrogen was after the known vacuum melting process, and its Content of diffusion hydrogen - determined according to the international standard ISO 3590.

The results of the mechanical tests carried out are shown in the table 2 listed.

Table 2 Cored wire, tensile strength, specific, notched impact strength Electrode capacity, kg / mm² strain (Charpy sample) kgm / cm² voltage,% + 20 ° C -20 ° -40 ° C A 53.2 28.5 10.5-11.2 4.5-5.3 2.0-3.5 B 57.0 29.2 12.5-13.8 6.5-7.0 3 , 5-4.0 C 62.0 24.5 9.8-10.2 4.3-5.0 1.8-3.0 To illustrate the advantages of full wire electrodes, the core of which is made from the powder composition according to the invention in the following table 3 comparative results of the physico-chemical analysis to determine the gas content in the weld metal with the application of an known technical solution achieved analogous results, cited (9. U.S. Patent No. 3800120).

Table 3 Cored wire electrode Gas content Total content of remaining (in weight and diffusion hydrogen, percent) cm³ / 100 oxygen nitrogen Hydrogen A 0.055 0.011 4.6 B 0.040 0.010 3.8 c 0.044 0.011 5.2 filler wire electrode according to U.S. Patent 0.09 0.016 12 No. 3800120 From Tables 2 and 3 it is can be seen that the cored wire electrodes, whose core is derived from the inventive Powder composition is made, the weld seam work tor with high mechanical Properties is obtained. In addition, the aforementioned full-wire electrodes excellent weld seam formation and good separability of the loop cover, as well as a high resistance to hot cracks and a low gas content achieved.

The efficiency of the welding process when using said Fti'li wire electrodes is 8 g / h, which is 1.5 times higher than the Welding performance using cored wire electrodes manufactured according to US Pat. No. 3800120 is.

Example 3 of a true welding process were full-wire electrodes with a diameter of 2.5 now used (conditionally referred to as A, B and C), the core of which is produced from the powder composition obtained according to the invention is. The steel jacket of the respective cored wire electrode was 70 percent by weight of the total mass of this electrode and had the following composition (in percent by weight ) on: carbon - 0.08; Manganese - 0.30; Silicon - 0.12; Sulfur - 0.030; phosphorus -0.030.

The welding of steel specimens was carried out in their normal position under Use of the semi-automatic process carried out with reverse polarity direct current.

Welding parameters: welding current ............... 450 A arc voltage ................ 32 V Carbon dioxide was used as the protective gas.

The steel to be welded with a thickness of 20 mm had the following Composition (in percent by weight ohlenstoft - 0.18; manganese - 0.45; silicon - 0.20; Sulfur - 0.020; Phosphorus - 0.015; remaining - iron.

The powder compositions from which the cores of the mentioned Cored wire electrodes are listed in Table 1.

Table 1 Components of the powder feed wire electrode composition of the electrical A B C Denkernes Quantitative composition of the powder mixture of the Electrode core (in percent by weight) rutile concentrate 20.0 -33.2 46.5 ferromanganese 10.0 12.5 15.0 ferrosilicon 1.30 2.0 2.60 sodium hexafluorosilicate 1.0 2.1 3.3 Burnt magnetite 1.3 5.6 10.0 Electro-corundum 1.6 4.1 6.7 Iron powder 64.8 40.5 15.9 ser weld seam material obtained by using the cored wire electrodes A, B and C. Mechanical tests to determine its notched impact strength became more specific Elongation and tensile strength, as well as a physico-chemical analysis to determine the content of gases such as oxygen and nitrogen in the weld metal and subjected to hydrogen.

The mechanical tests of the weld seam material were measured carried out the per se known method.

The content of oxygen, nitrogen and the rest of the weld metal Hydrogen was produced by the vacuum melting process known per se, and the Content of diffusion hydrogen - determined according to the international standard ISO 3690.

The results of the mechanical tests carried out on weld material are listed in Table 2.

Table 2 (@@@ cored wire, tensile, specific, notched impact strength de strength- en elongation (Charpy test), kgm / cm, tension, S0 kg / mm2 + 20 ° C 200C -40 OG 50.2 29.5 12.1-12.4 4.5-4.8 3.04.2 B 54.3 29.8 13.5-14.1 6.5-7.1 3.5 -4.5 C 60.0 23.0 10.5-11.1 4.0-4.3 2.8-4.4 The gas content of the weld metal is shown in the table 3 listed.

Table 3 Cored wire electrode gas content (in Ge total content of residual weight percent) chemical and diffusion hydrogen, cm3 / 100 g oxygen oxygen hydrogen 2 2 3 4 0.050 0.010 5.0 1 2 3 4 B 0.034 0.008 3.6 c 0.041 0.012 4.1 Cored wire electrode according to US-PS 0.09 0.016 12 Er. 3800120 From table 2 it can be seen that by the cored wire electrodes, the cores of which are made from the powder composition according to the invention are made, the weld seam material with high mechanical properties can be obtained. In addition, the aforementioned filler wire electrodes achieves excellent weld seam formation in the normal weld position.

Such weld seams have good resistance to hot cracks and a low gas content.

The performance of the welding process is 15 kg / h. the linear speeds of the corner seam welding are depending on the Suture cathet 50 to 80 m / h.

Example 4 (negative) The welding was essentially carried out on the carried out in the manner described in Example 1. During the welding process however, a cored wire electrode was used, the core of which is made of a powder composition was manufactured, in which the components were contained in amounts that correspond to the in Go below claim 2 specified lower limit values. The diameter this filler wire electrode was 1.6 mm. The steel jacket of the cored wire electrode was 83% by weight of the total filament wire electrode mass and had the following souping up on (in percent by weight): carbon - 0.06; Manganese - 0.23; Silicon - 0.09; Sulfur - 0.020; Phosphorus - 0.020.

Welding parameters: welding current .............. 4> 0 A arc voltage ........ 36 V The powder composition of the mentioned cored wire electrode is below listed: rutile concentrate ............................................... ......... 19.5 Ferromanganese .............................................. .............. 9.8 Ferrosilicon ................................................. ......... 1.0 sodium hexafluorosilicate ............................................... 0.8 burnt magnesite ................................................ .... 1,2 Electro-corundum .............................................. ............ 1.4 Iron powder ................................................. ........... rest Below are the results of the mechanical tests carried out on the weld seam material general: tensile strength, kg / mm2 ................... 47.0 specific elongation, . . . . . . . . . . . . . . . . . . . . . . 24.0 notch impact strength (Charpy test), kgm / cm²: at +20 0C ........,., ...., ..., ..., ....., .... 7.2-7.5 at -20 ° C .............................................. ............... 2.0-2.3 at -40 ° C ...................................... ....................... 1.2-1.5 From the above results of the mechanical tests it can be seen that aass when using filler wire electrodes with the powder composition mentioned uphold the welding of the weld seam material with deteriorated mechanical Properties is formed and it to increase its pore and there is a tendency to crack. In addition, there is a deterioration in stability burning the arc and increasing the amount of splashing of electrode metal.

Example 5 (negative) The welding was essentially carried out on the im Example 3 described manner carried out. During the welding process however, a cored wire electrode was used in which the ingredients in quantities were included, which the in the patent claim 2 specified upper limit bet exceed. The diameter of this full wire electrode was 2.5 mm. The steel jacket of the cored wire electrode was 70 percent by weight of the total cored wire electrode mass and had the following composition (in percent by weight carbon - 0.08; manganese -0.30; Silicon - 0.12; Sulfur - 0.030; Phosphorus - 0.030.

Welding parameters: welding current .................... 450 A arc voltage 32 V The powder composition of the cored wire electrode is listed below: rutile concentrate .................................. 47.0 Ferromanganese ............ .......................... 23.0 forrosilicon. . . . . . . . . . . . . . . . . . . . . . . . . 6.2 sodium hexafluorosilicate ......................... 5.2 burnt magnesite .................... .......... 10.2 Ekeltrokorund .................................... 7.7 Iron powder ...... ................................ Remaining below are the results of the mechanical performed Exams of the weld seam material: tensile strength, kg / mm² ....................................

specific elongation,% ....................... 19.5 notched impact strength (Charpy sample) kgm / cm²: at + 2u ° C 8.0-9.2 at -20 ° C ................. 1.7-2.0 at -40 OC ........................................ 1.1-1, 3 Like it from the above can be seen, is by increasing the content of ingredients the powder composition of the cored wire electrode core above that in claim specified upper limit value the deterioration of the welding technology Properties of the mentioned filler wire electrode caused, It comes to the enlargement the spraying of electrode metal, to the deterioration of the weld seam formation and to reduce plastic core data of the weld seam.

Specific examples of implementation of the invention are given above, which allow various modifications and additions to the person skilled in the art are familiar with this area of technology. There are other changes as well Additions are possible, but the errinaungstatstatus and -umrangement in the frame of the claim mentioned below are retained.

Claims (2)

Powder composition for filler wire electrodes PATENT CLAIMS 1. Powder composition for cored wire electrodes for protective shell welding and protective shell deposition welding of steels containing rutile concentrate, ferromanganese, ferrosilicon and iron powder, in that it also contains the following components: (a) Sodium hexafluorosilicate, (b) burnt magnesite (c) electro corundum. 2. Powder composition according to claim 1, characterized in that g e -k e n n z Note that the ingredients of the powder composition in their following Ratio (in percent by weight) includes: rutile concentrate ....................................... 20 - 53 Ferromanganese ...................................... 10 - 22.8 Ferrosilicon .......................................... 1.3 - 6 sodium hexafluorosilicate .. ............................. 1 - 5 burnt magnesite ................................. 1.3 - 10 electro corundum .......................................... 1.6 - 7.5 iron powder .................................................. .......... Res