Effect of Electrode Coating Type on the Physico-Chemical Properties of Slag and Welding Technique

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Ilona Jastrzębska, Jacek Szczerba, Paweł Stoch, Ryszard Prorok, Edyta Śnieżek Effect of Electrode Coating Type on the Physico-chemical Properties of Slag and Welding Technique

Abstract: The article presents the results of the physico-chemical tests concern- ing the properties of various slags formed after welding with low-hydrogen and rutile electrodes as well as flux-cored wires. The slags tested were analysed for their phase compositions using X-ray diffractometry (XRD) X-ray fluorescence (XRF). The behaviour of slags at temperatures elevated to 1400°C was examined using a high-temperature microscope. The analysis of the high-temperature tests enabled the determination of slag characteristic temperatures, i.e. softening and melting points. The results obtained demonstrated various properties of slags, with the low- est characteristic temperatures for low-hydrogen slags and the highest characteristic temperatures for flux-cored wire slags. In addition, on the basis of different characteristic temperatures slags were classified in relation to their solidification rates.

Keywords: low-hydrogen electrodes, rutile electrodes, flux-cored wires, slag properities

Introduction Welding using covered electrodes and flux-cored wires is an important and indispensable technique while performing welding processes in construction site conditions. Slag formed during welding by means of these methods pro- tects a weld pool against oxidation, stabilises arc burning, ensures the proper chemical composition of a weld and provides the insulation Fig. 1. Weld in cross-sectional view protection thereof (Fig. 1). The type and chemical composition of coatings significantly affect The production of covered electrodes is a mul- the mechanical strength of a weld. In addition, ti-stage process (see Fig. 2). the physical properties of solid-state and liquid The first and most important issue in the pro- state coatings, such as grain size, viscosity, sur- duction of covered electrodes is the chemical face tension, thermal expansion coefficient and composition of the coating mixture. The var- heat capacity also influence the obtainment of ious behaviours of mixtures and fluxes avail- a good quality weld in a required shape [1-6]. able on the market depend on their chemical

mgr inż. Ilona Jastrzębska (MSc Eng.); dr hab inż. Jacek Szczerba (PhD (DSc) habilitated Eng.); dr inż, Paweł Stoch, Professor Extraordinary (PhD (DSc) Eng.); mgr inż. Ryszard Prorok (MSc Eng.); mgr inż. Edyta Śnieżek (MSc Eng.) - AGH University of Science and Technology, Kraków

No. 1/2015 BIULETYN INSTYTUTU SPAWALNICTWA 37 Initial mixture of fine The reaction of carbonate decarbonisation raw materials is endothermic in nature. In this reaction, released CO₂ makes up 44% of the total calcite Homogenisation of the dry mass. The transport of CO₂ takes place as a re- mixture of raw materials sult of Knudsen diffusion through voids and cracks between phases and through spaces Homogenisation of the wet formed due to the separation of CaO crystals mixture of raw materials (raw materials + filler metals) from CaCO₃ not yet decomposed [8]. J.D. Ples- sis and the co-authors [9] examined the effect of calcium carbonate content in the phase compo- Forming – pressing sition of a low-hydrogen coating mixture on the content of hydrogen diffusing in a weld metal, with calcite content in the mixture varying be- “Brushing” tween 10% and 24%. Tests revealed a decreas- ing amount of hydrogen in a weld for mixtures containing up to 18% of CaCO₃. Greater CaCO₃ Drying amounts produced the opposite effect. While preparing coating mixtures it is also possible to use a number of other carbonates Visual inspection (Table 1), yet they are used to a lesser degree. As can be seen in Table 1, the mineral releasing Fig. 2. Simplified production scheme the greatest amount of CO₂ is magnesite, whilst of covered electrode production iron carbonate (siderite) decomposes releasing composition, the geological origin of the raw the smallest amount of the above mentioned materials used for their production and the gaseous compound. It should be emphasized manufacturing process itself [1]. The selection that among all basic oxides it is calcium oxide of raw materials for the preparation of a coating that has the greatest ability to absorb and fix wa- depends on the required phase composition of a ter in the structure, hence its excellent capabili- dry mixture. Having the foregoing in view, such ty of reducing hydrogen and oxygen contents in a dry mixture should contain minerals, which a molten metal area. The ability of magnesium during welding, release gases stabilising an arc and protecting the liquid weld pool. The most Table 1. Minerals containing the carbonate group (CO₃2-), commonly used minerals providing gaseous the products of their thermal decomposition protection include calcite, supplied with lime- and the amounts of CO₂ released in stone, having a chemical formula of CaCO₃. The a decarburisation reaction [3,4]. thermal decomposition of CaCO₃ takes place Thermal Amount of at 950°C, leading to the formation of CaO and Mineral decomposition released CO₂, products % by weight CO₂ (1), which, in turn decomposes (in arc plas- calcite – CaO, CO₂ 44.0 ma) into carbon monoxide and atomic oxygen CaCO₃ in accordance with the reactions (2, 3) [7]: magnesite – MgO, CO₂ 52.2 CaCO₃→CaO + CO₂↑+ 178 kJ/mol (1) [7,8] MgCO₃ siderite – FeO, CO₂ 38.0 2CO₂↑→2CO↑+ O₂↑ (2) [9] FeCO₃ dolomite – CO↑→C +½O₂↑ (3) [9] MgO, CaO, CO₂ 47.7 CaMg(CO₃)₂

38 BIULETYN INSTYTUTU SPAWALNICTWA No. 1/2015 oxide to react with water is significantly infe- commonly used in the production of coating rior if compared with that of CaO, which is mixtures and is provided in the form of fluorite additionally responsible for the predominant (melting point 1418°C). As the low-hydrogen popularity of calcium carbonate [10-16]. (basic) components of mixtures are character- The thermal decomposition of magnesite and ised by a greater ability to fix water, CaF₂ is that of siderite are similar, in accordance with commonly used in the production of low-hy- the reaction (1). In turn, dolomite decomposes drogen (basic) electrodes. Tests conducted by in a two-stage reaction. During the first stage, at C.S. Chai and co-authors [18] revealed that flu- a temperature of 700-750°C, reaction products orine, F₂, reacts with hydrogen molecules form- are CaCO₃, MgO and CO₂. The second stage ing hydrogen fluoride, HF, in accordance with takes place at a temperature of 900-1000°C and the reaction (4): leads to the decomposition of CaCO₃ into CaO F₂+H₂→2HF↑ (4) [9] and CO₂ [16]. It should be mentioned that the greater the carbonate fraction, the higher the ba- Hydrogen fluoride does not dissolve in liquid sicity of slag and the lower the hydrogen content iron and evaporates from an arc area [9]. Sadly, in a weld [9]. This is due to a greater tendency calcium fluoride is not sufficiently active and to fix water in a structure through the absorp- its part enters slag. Therefore, it seems advisa- tion of hydrogen from arc plasma, which pre- ble to investigate the behaviour of other fluo- vents the hydrogen from entering a liquid metal. rides. It has been found that calcium fluoride Other raw materials used in the production in the presence of silicon dioxide, SiO₂, reduc- of coatings include clays containing alumin- es its oxidising ability forming silicon fluoride, ium silicates e.g. kaolinite – Al₄Si₄O₁₀(OH)₈, SiF₄, as can be seen in the reaction (5): alkaline feldspars containing aluminosili- 2CaF₂+SiO₂→SiF₄↑+2CaO (5) [18] cates such as orthoclase (KAlSi₃O₈) and albite (NaAlSi₃O₈), quartzites enriched in silicon di- During submerged arc welding it is possible to oxides (96-98 % mol.) and high-purity tita- observe the formation of a small amount of sil- nium dioxide containing over 95% TiO₂. The icon fluoride which decreases the partial pres- third group is composed of ferroalloys sup- sure of hydrogen. In addition, it has been found plied to a mixture in order to deoxidise a liq- that the formation of SiF₄ does not reduce the uid metal in a weld. Ferromanganese (FeMn), content of silicon in a weld [18]. T. Lau and ferrotitanium (FeTi) and ferrosilicon (FeSi) co-authors [19] noticed the reaction between belong to the group of deoxidising raw mate- calcium fluoride and aluminium oxide in slag, rials most commonly used for the preparation in accordance with the equation (6): of coating mixtures and fluxes. The addition of 3CaF₂+Al₂O₃→2AlF₃↑+3CaO (6) [19] fine iron (Fe) enables faster melting of the electrode, thus increasing welding process efficien- Fluorite is entirely included in the slag ratio, cy. Welding without the aforesaid component expressed by a basic component – acidic com- requires greater power consumption, is respon- ponent ratio in accordance with the equation sible for a droplet-type liquid metal transport (7), describing the metallurgical behaviour of mode (more difficult to control) and leads to a a coating mixture and having a significant ef- greater number of spatters [18]. fect on the toughness of a weld [12]. The high- The appropriate fluidity of molten slag and er the basicity, the lower the hydrogen content the reduction of diffusive hydrogen content are in a weld and the greater the toughness of a obtained by adding components containing flu- weld [12,20]. oride ions [9]. Calcium fluoride, CaF₂, is most

No. 1/2015 BIULETYN INSTYTUTU SPAWALNICTWA 39 BI=(CaO+MgO+BaO+SrO+Na₂O+K₂O+ prevents the excessively fast drying of a mix- Li₂O+CaF₂+0,5∙(MnO+FeO))/ ture, which could trigger the formation of cracks (SiO₂+0,5∙(MnO+FeO)) (7) [20] on a coating surface. Plasticisers of graining H. Terashima and co-authors [21] have observed below 0.3 mm are used in small amounts (ap- a decrease in the content of hydrogen diffus- proximately 0.5-1%) as additions to mixtures ing in a weld from 12 to 2ml per 100g of molten [24]. A coating is pressed by a set of nozzles, metal with a slag ratio increasing from 0 to 3 re- uniformly covering a wire. The precise control spectively. It has been established that the type of nozzle alignment is of crucial importance of oxide present in a coating mixture affects the for the obtainment of uniformly covered elec- ease of slag separation from the surface of a weld. trodes. After pressing, covered electrodes un- The presence of calcium fluoride is responsi- dergo heat treatment. ble for the difficult separation of slag, similarly The process of heat treatment depends on as in the case of cordierite – Mg₂Al₃[AlSi₅O₁₈] the chemical composition of an electrode and and the solid solution of spinel (Mg, Mn, Cr) is conducted at various temperatures in a one O∙(Al, Cr, Mn)₂O₃. Slag behaves otherwise in or two-stage process, depending on the type cases of increased amounts of SiO₂, Al₂O₃ and of electrode: Cr₂TiO₂, the presence of which facilitates the –– rutile electrodes – one-stage drying (approx- separation of slag [1]. imately 105°C), The chemical composition and the physi- –– low-hydrogen (basic) electrodes – two-stage co-chemical properties of a coating mixture, drying 1: 100°C, 2: 420-450°C). dependent on the raw material used, have a The first stage of drying aims to remove hygro- significant influence on the penetration depth scopic water, whereas the second stage of the [1,22]. T.H. Hazzlet [23] noticed that the pres- heat treatment of low-hydrogen electrodes is ence of pure CaCO₃, K₂CO₃ and CaF₂ causes connected with the fact that basic compounds shallow penetration, whereas Na₃CO₃, MnO₂, are characterised by significant water absorp- Al₂O₃, SiO2 and MgO lead to the obtainment tion and hydration tendency [24]. During the of a medium depth of penetration. It has also heat treatment of electrodes the gases formed been found that the presence of MgCO₃ in as a result of the reaction between ferroalloys a coating mixture ensures the obtainment of (particularly FeSi) and sodium silicate can im- deep penetration. pede the drying process and increase crack Binding agents constitute another important formation susceptibility. For this reason, the group of components used in the production of traditional addition of fine FeSi to a mixture coating mixtures applied exclusively for man- has been replaced by the addition of FeSi pro- ufacturing covered electrodes as they provide duced in the process of spraying. The particles the sufficient strength of a mixture during and of sprayed ferroalloy are covered with a thin after the process of formation. The solutions of layer of silicon oxide and, as a result, are less

sodium and potassium silicates (Ma(SiO₂)bO, susceptible to reacting with sodium silicate. where M=Na+ or K+) are used mainly as filler The objective of this study is to determine the metals. This group of chemical compounds af- physico-chemical behaviour of various types of fects the centricity of a covered electrode, be- slag specimens formed during welding with ver- ing a precondition for stable arc burning and tical upwards progression (PF), using various proper weld formation, particularly while mak- welding consumables available on the market, ing root runs [18]. The addition of carboxyme- as well as to assess their impact on a welding thylcellulose or cellulose (in low-hydrogen and technique. rutile electrodes respectively) as a plasticiser

40 BIULETYN INSTYTUTU SPAWALNICTWA No. 1/2015 Materials and Table 2. Characteristics of materials used in the tests Methods Material/ Electrode European Slag Producer electrode The study-related tests in- welding method designation designation designation volved the use of several E 38 3 B 12 types of electrodes avail- Oerlikon Special according to BO able on the market, i.e. EN ISO 2560-A three grades of low-hy- Low-hydrogen E 38 3 B 42 drogen electrodes and electrodes/ Esab EB146 according to BE 111 EN ISO 2560-A three grades of rutile elec- E 42 2 B 32 trodes. In addition, the Metalweld EVB47 according to BM tests also included one EN ISO 2560-A grade of a rutile flux- E 38 0 R 12 cored wire. The charac- Oerlikon Overcord according to RO teristics of the materials EN ISO 2560-A tested are presented in Rutile E 38 0 R 12 Table 2. Welds were made electrodes/ Esab ER146 according to RE 111 EN ISO 2560-A of S355J2+N steel in ver- E 38 0 R 12 tical upwards progres- Metalweld Rutweld 13 according to RM sion (PF) (in accordance EN ISO 2560-A with EN 10025-2) [25,26]. T 46 4 Z P M 2 H5 Flux-cored wire/ Nittetsu SF-3AM according to FCW The diameter of the elec- 136 trodes and rutile flux- EN ISO 17632-A cored wire used amounted to 3.2 mm and The slag specimens sampled were subjected to a 1.2 mm respectively. Welding current adjust- phase analysis using an X-ray diffractometer (XRD; ed for the electrodes amounted to 100 A and X’Pert Pro by Philips) in the range of angles 2 theta that for the flux cored wire was 190 A. Dur- 5-90°, applying radiation Cu Kα (λ=1.54056 Å) and ing the tests involving the flux cored wire the to chemical element analysis using X-ray fluores- shielding gas used was a mixture composed of cence (XRF; Philips X’Unique II). The specimens 80% Ar and 20% CO₂ (M21). Slag specimens were also examined using a high-temperature mi- were sampled from the welds and designated croscope at a temperature of 1400°C and a heat- as presented in Table 2. ing rate of 10°C/min.

Table 3. Chemical element analysis of slag specimens Chemical element content, % by weight Specimen O Ca Si Mg Ti Mn Fe K Na Al Cr F Low-hydrogen slag BO 37.2 23.4 16.7 1.6 3.1 7.1 6.1 1.8 0.2 0.6 0.1 2.1 BE 32.2 32.7 10.2 0.1 5.9 4.6 2.8 0.9 0.9 0.5 0.03 9.2 BM 31.9 31.2 8.9 0.3 8.6 3.9 4.1 1.3 0.1 0.4 0.04 9.3 Rutile slag RO 38.6 3.6 9.7 0.1 24.3 8.5 8.3 3.1 0.7 3 0.1 - RE 38.3 3.8 8.3 0.1 25.9 10.1 8.1 1.1 1.7 2.5 0.1 - RM 39.7 2.4 9.5 0.1 26.3 8.1 6.6 3.2 0.3 3.7 0.1 - Flux-cored wire slag FCW 37 0.1 2.3 4.7 37.7 11.9 1.5 0.2 1.8 1.3 0.04 1.5

No. 1/2015 BIULETYN INSTYTUTU SPAWALNICTWA 41 Results and Discussion to achieve due to a high temperature, density Table 3 presents the chemical element analysis gradient, very fast heat transfer from an arc and of the slag specimens conducted using the XRF a significant number of various slag and met- method. As can be seen, the chemical compo- al phases. The thermodynamic equilibrium of sitions of the BE and BM slags are similar. The a welding process is obtained only locally in contents of the main elements such as Ca, Si, small volumes, at high temperatures and for a Ti and Mn are similar in the BE and BM slags. high area to volume ratio. For this reason, it is In turn, the BO slag contains less Ca and Ti and necessary to act prudently while using equi- more Si and Mn. The chemical composition of librium conditions [14]. The presence of other the rutile electrodes tested is similar. The FCW phases in the composition of slag cannot be ex- slag is characterised by smaller amounts of Si cluded, yet their amount can be below the XRD and Ca and greater amounts of Mg, Ti and Mn method limit of detection or such phases may if compared with the slag obtained from the be not fully ordered. rutile electrodes. The main phase in the rutile electrode slag (RO, Figure 3 presents the results of the low-hy- RE, RM) composition is Fe₂MnTi₃O₁₀ of orthor- drogen slag XRD analysis. The diffraction pat- hombic symmetry (Fig. 4). All the specimens, terns of the BE and BM specimens reveal their tested using XRD, also revealed the presence of multi-phase nature. The diffraction pattern of iron titanate FeTiO₃ having the structure of per- the BO specimen presents a strongly amorphous ovskite. TheXRD diffraction pattern of the flux- structure, resulting from a greater fraction of cored wire (FCW) slag is analogous to that of the a silicate phase having undergone fast cool- rutile electrode slag. Slight displacements in re- ing-induced vitrification. The diffraction -pat flex positions in both phases can be attributed tern of the BO specimen is typical of compounds having an amorphous structure. In order to provide better characteristics and understand the BO slag “behaviour”, conducting ad- ditional tests, e.g. employing infra- red spectroscopy (IR), seems highly advisable. The diffraction patterns of the BE and BM specimens contain reflexes characteristic of fluorite, silicates and titanates as well as a Fig. 3. Diffraction patterns of low-hydrogen electrode (BO, BE, BM) slags high-intensity reflex originating from rutile at 2θ=27.52° (BE specimen) and at 2θ =27.39° (BM specimen). Simi- lar phases were previously recorded in relation to post-weld slag by C.T. Vaza and co-authors [4]. In addition, the diffraction pattern of theBM slag is characterised by a greater amount of higher intensity reflexes for calcium titanate CaTiO₃. The equilibrium in a pyrometallur- Fig. 4. Diffraction patterns of (RO, RE, RM) rutile electrode slags gic reaction is known to be difficult and flux-cored wire (FCW) slag

42 BIULETYN INSTYTUTU SPAWALNICTWA No. 1/2015 to the isovalent and heterovalent substitution of 900°C. The thermal behaviour of the BE and BM iron ions with magnesium ions (Mg2+↔Fe2+/3+) specimens is similar, the effect of which will be present in the slag, due to a very small difference their similar behaviour during welding and the in their electronegativity in the electrochemi- obtainment of similar quality welds. The low

cal series and ionic radiuses (rMg2+=0.072 nm, melting point of low-hydrogen slag imposes rFe2+=0.078 nm, rFe3+=0.065 nm) (Table 3). the necessity of using a short arc welding tech- The selected characteristic temperatures of nique, which will also protect the weld pool the slag specimens tested, such as softening against overheating [6,25-29]. and melting points, were determined by ob- The observation of the rutile slags revealed serving the changes of specimen shapes during their higher softening and melting points if high-temperature microscopic observations. compared with those of low-hydrogen slags. The characteristic values of slag temperature Significantly higher melting points of rutile are presented in Table 4. The photographs for slags enable the obtainment of high-quality the BO specimen softening and melting points welds using long-arc welding techniques [30]. are presented in Figure 5. It was observed that However, high solidification points of rutile the BO low-hydrogen slag had lower softening slags can confine residual gases in a weld, pos- and melting points. Such a behaviour can be as- sibly leading to its increased porosity and re- cribed to the significant amount of the amor- duced mechanical strength [26]. phous phase, detected using the XRD method TheFCW slags are characterised by the high- (Fig. 3, BO). The microscopic observations also est softening and melting points and a relatively revealed a small temperature range (approxi- small temperature range of 40°C between these mately 30°C) between the softening and melting points, indicating the fast solidification of the points (Fig. 5). The specimen started to soften slag. The fast FCW slag solidification prevents at 1100°C and was entirely molten at 1130°C. the weld pool from hanging down. As a result, The BO slag melting point is lower by approx- electrodes can be used for welding positions imately 85°C than the softening points of the considered as difficultPF ( and PG) and at high- BE and BM slags. As a result, welding by means er welding parameters, which increases weld- of BO electrodes makes it possible to use lower ing process efficiency [31]. The melting point welding parameters with simultaneously main- of the FCW specimen is higher than that of any taining electrode melting stability. The small other rutile slags, probably due to higher con- temperature range between the softening and tents of magnesium and manganese ions built- melting point and high viscosity, caused by an in in the crystalline structure of the FCW slag increased amount of silicates (Table 3, Fig. 3-BO) specimen. During the tests it was observed that prevent the outflow of slag and the fall of liquid metal making weld- Table 4. Results of observations using a high-temperature microscope ing in difficult positions, such as Temperature range Slag Softening Melting PF, PE, PD or PG, significantly easier. between the melting designation point, °C point, °C In addition, the low solidification and softening points, °C point of the slag enables the release BO 1100 1130 30 of gases from a weld and is respon- BE 1170 1200 30 sible for lower weld porosity. Dur- BM 1200 1230 30 ing the microscopic examination of RO 1160 1260 100 the BM specimen it was possible to RE 1150 1240 90 observe the release of residual gas- RM 1200 1270 70 es from the slag at a temperature of FCW 1360 1400 40

No. 1/2015 BIULETYN INSTYTUTU SPAWALNICTWA 43 20°C 1000°C 1050°C the FCW welding parameters are almost twice as high if compared with welding using a covered electrode in the same welding position. 1100°C 1120°C 1130°C Conclusions The research involved welding tests in vertical upwards progression using electrodes provided with Fig. 5. Photographs of the BO specimen observed using a high-tempera- low-hydrogen and rutile coatings ture microscope (1100°C-softening point, 1130°C-melting point). as well as using flux-cored wires. Slags collected from a surface welded were sub- Acknowledgements jected to a chemical analysis, phase analysis and The authors wish to express their thanks to microscopic examination using a high-temper- the Spaw-Projekt Company from Kraków for ature microscope. The results of microscopic making the welds and to the “Instytut Łącze- examination were interpreted with reference to nia Metali” Company from Kraków for finan- the chemical element composition and phase cially supporting the research. composition as well as in relation to their effect The work was partly financed with the stat- on the welding technique. The most important utory finances of the Faculty of Materials Sci- results obtained are presented below: ence and Ceramics, AGH. 1. Welding with a BO low-hydrogen covered electrode leads to the formation of slag en- References riched in an amorphous phase having a sig- [1] Singh B., Khan Z.A., Siddiquee A.N.: Re- nificant effect on the welding technique. The view on effect of flux composition on its -be increased viscosity of the amorphous silicate havior and bead geometry in submerged arc phases is responsible for better adhesion of liq- welding (SAW). Journal of Mechanical Engi- uid slag to the weld pool thus facilitating weld- neering Research, 2013, vol. 5 (7), pp. 123-127. ing in difficult positions without slag flowing [2] Indacochea J.E., Blander M., Christensen off and without the weld pool hanging down, N., Olson D.L.: Chemical reactions during which was observed during the test performed Submerged Arc Welding with FeO-MnO- in the restricted PF position. SiO₂ fluxes. Metallurgical Transactions B, 2. Due to the higher melting point of rutile 1985 vol. 16B, pp. 237-245. electrode slags it is possible to use a welding [3] Lau T., Weatherly G.C., Lean A.: The sourc- technique employing an extended arc, facili- es of oxygen and nitrogen contamination in tating welding in difficult positions. However, submerged arc welding using CaO-Al2O3 the high temperature of rutile slag solidifica- based fluxes. Welding Research Supplement, tion can be responsible for the confinement of pp. 343-348, 1985. gases inside the weld. [4] Vaz C.T., Bracarense A.Q., Felizardo I., Pes- 3. Slag formed while welding with a flux- soa E.C.: Impermeable low hydrogen cov- cored wire (FCW) reveals the highest softening ered electrodes: weld metal, slag, and fumes and melting points as well as the low tempera- evaluation. Jounal of Materials Research and ture range between them. As a result, the slag Technology, 2012, no. 1 (2), pp. 64-70. solidifies faster and enables welding in difficult [5] Jastrzębski R., Padula H., Trześniewski K., positions, e.g. in vertical progression, at high Jastrzębski A.: Steering algorithms of the root welding parameters, i.e. approximately 180 A. pass and the face for pressure high strength

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No. 1/2015 BIULETYN INSTYTUTU SPAWALNICTWA 45 urządzeń. Przegląd Spawalnictwa, 2010, no. 5 [30] Jastrzębski R., Padula H, Zielińska M., (82), pp. 5-10. Yalinkilicli B., Cenin M., Latala Z., Kościusz- [28] Jastrzębski R., Cenin M., Jędrzejko J., ko T., Dexter M., Godniak M., Kaczor M.: Zieliński J., Jastrzębski K., Padula H.: Za- Using space technic solution to design in- stosowanie metody szkolenia spawaczy TKS telligent visual systems of industrial robots. do precyzyjnego wykonania przetopu i lica Dokument MIS XII-1831-04. elektrodą zasadową w pozycjach przymuso- [31] Jastrzębski R., Mikuła J., Skarpetowski M., wych. Biuletyn Instytutu Spawalnictwa, 2005, Żurek J.: Porównanie techniki spawania elek- no. 3, pp. 61-64. trodami otulonymi z drutami proszkowymi [29] Jastrzębski R., Pawlik (Jastrzębska) I.: rutylowymi i zasadowymi. Przegląd Spawal- Wady połączeń spawanych. Projektowanie nictwa, 2011, no. 5 (83), pp. 45-47. i konstrukcje inżynierskie, 2011, no. 12 (51).

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