Soldagem mag com braço robótico de aços ASTM A36 E CSN civil em perfil estrutural dobrado a frio
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Data
2016-12-14
Autores
Pereira, Josemairon Prado [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Diversos fatores podem afetar a fabricação e a montagem de estruturas metálicas, tais como os inerentes ao processo fabril, equipamentos, parâmetros de soldagem, consumíveis e o tipo de gás de proteção. Nesse ramo, as indústrias utilizam largamente a chapa dobrada, nos aços ASTM A36 e CSN Civil-300 para obter juntas soldadas de alta qualidade. Para isso, três variáveis precisam permanecer com baixa variabilidade e dentro de limites confiáveis: as propriedades mecânicas, a distorção e a corrosão na junta soldada. Este trabalho focaliza o processo de soldagem MAG, com o uso do braço robótico Motoman UP6, quanto ao comportamento do aço estrutural em relação a distorção, corrosão e as propriedades mecânicas na junta soldada. Diante disto, o perfil de aço ASTM A36 em chapa dobrada tipo U 100x50x3,0 mm e U 100x50x2,7 mm, formado no aço ARBL CSN Civil-300 foram aplicados ao processo de soldagem MIG/MAG. Neste processo, utilizou-se quatro tipos de juntas experimentais (com e sem ponteamentos), dois tipos de arames-eletrodos, AWS ER70S-3 e AWS ER70S-6, proteção gasosa de 75%Ar-25%CO2, e parâmetros de soldagem que permitiram manter constante a densidade de corrente. Para tanto, foram utilizados o método de escaneamento tridimensional para avaliação da distorção na junta soldada, o método de aceleração da corrosão por névoa salina para avaliação da corrosão, as propriedades mecânicas foram avaliadas baseando-se na medição de microdureza, além disso, foram feitas análise química e observação das imagens macrográficas dos aços ASTM A36 e CSN Civil-300 das juntas soldadas com os arames-eletrodos AWS ER70S-3 e AWS ER70S-6. Com relação aos resultados obtidos, verificou-se que a distorção apresentou deslocamento inferior a 0,45 mm na superfície da amostra. O aço CSN Civil-300 apresentou maior resistência a corrosão, com a menor perda de massa de 0,0018 mm/ano. A medida de microdureza, nessas uniões, evidenciou redução média de 13% usando o arame-eletrodo AWS ER70S-3 com cordões de soldas de aspectos visuais e composições químicas satisfatórias.
Several factors may affect the manufacture and building of metal structures, such as those inherent in the manufacturing process, equipment, welding parameters, consumables and the type of shielding gas. In this business, industries widely use the sheet bended in steel ASTM A36 and CSN Civil-300 for welded joints of high quality. For this, three variables need to remain with low variability and within reliable limits: the mechanical properties, distortion and corrosion the welded joint. This work focuses on the MAG welding process, using the robotic arm Motoman UP6, as the structural steel behavior in relation to distortion, corrosion and mechanical properties in the welded joint. Given this, the steel profile ASTM A36 bended plate type U 100x50x3,0 mm and U 100x50x2,7 mm, formed in HSLA steel CSN Civil-300 were applied of the MIG/MAG welding process. In this process, we used four types of experimental joints (with and without picking), two types of electrode wire AWS ER70S-3 and AWS ER70S-6, shielding gas 75%Ar-25% CO2, and with welding parameters which allowed maintaining constant the current density. Therefore, we used three-dimensional scanning method for evaluation of distortion in the welded joint, the method of accelerated corrosion by salt spray to evaluate the corrosion and mechanical properties were evaluated based on the microhardness measurement, in addition, analysis chemical and observation of the macrographics images of ASTM A36 and CSN Civil-300 steels welded together with the AWS ER70S-3 and AWS ER70S-6 electrodes wires. Regarding the obtained results, it was verified that the distortion introduced displacement of less than 0,45 mm on the sample surface. The Civil-300 CSN steel showed higher resistance to corrosion, with the lower mass loss of 0,0018 mm / year. The microhardness measurement at these joints showed 13% average reduction using AWS ER70S-3 electrode wire with visible chemical weld beads and satisfactory chemical compositions.
Several factors may affect the manufacture and building of metal structures, such as those inherent in the manufacturing process, equipment, welding parameters, consumables and the type of shielding gas. In this business, industries widely use the sheet bended in steel ASTM A36 and CSN Civil-300 for welded joints of high quality. For this, three variables need to remain with low variability and within reliable limits: the mechanical properties, distortion and corrosion the welded joint. This work focuses on the MAG welding process, using the robotic arm Motoman UP6, as the structural steel behavior in relation to distortion, corrosion and mechanical properties in the welded joint. Given this, the steel profile ASTM A36 bended plate type U 100x50x3,0 mm and U 100x50x2,7 mm, formed in HSLA steel CSN Civil-300 were applied of the MIG/MAG welding process. In this process, we used four types of experimental joints (with and without picking), two types of electrode wire AWS ER70S-3 and AWS ER70S-6, shielding gas 75%Ar-25% CO2, and with welding parameters which allowed maintaining constant the current density. Therefore, we used three-dimensional scanning method for evaluation of distortion in the welded joint, the method of accelerated corrosion by salt spray to evaluate the corrosion and mechanical properties were evaluated based on the microhardness measurement, in addition, analysis chemical and observation of the macrographics images of ASTM A36 and CSN Civil-300 steels welded together with the AWS ER70S-3 and AWS ER70S-6 electrodes wires. Regarding the obtained results, it was verified that the distortion introduced displacement of less than 0,45 mm on the sample surface. The Civil-300 CSN steel showed higher resistance to corrosion, with the lower mass loss of 0,0018 mm / year. The microhardness measurement at these joints showed 13% average reduction using AWS ER70S-3 electrode wire with visible chemical weld beads and satisfactory chemical compositions.
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Palavras-chave
Processo de soldagem, Distorção, Corrosão, Propriedades mecânicas, Estruturas metálicas, Process welding, Distortion, Corrosion, Mechanical properties, Metal structures