O propósito deste trabalho é estudar as forças de corte envolvidas no processo de fresamento de bordas de chapas utilizadas para a fabricação de tubos de aço com costura e como estas variam em função dos parâmetros de corte utilizados. O objetivo é correlacionar estas forças à qualidade do acabamento superficial das bordas usinadas, uma vez que esta é fundamental para a qualidade final da solda do tubo. Para isso, foi construído um dinamômetro de mesa para medição das forças, e os dados foram analisados através do Método da Regressão Linear Múltipla. Os resultados obtidos demonstraram que, tanto para a força de corte quanto para a rugosidade da superfície usinada, o parâmetro que mais influencia é o avanço por dente, seguido pela largura de corte, sendo que o que menos influencia é a velocidade de avanço. Estes resultados foram comprovados com êxito no processo industrial foco deste estudo através da medição da corrente elétrica dos motores dos eixos-árvore e da vibração dos mesmos. / This work aims to study the cutting forces involved in the edge milling process for welded pipes manufacturing and how these forces vary due to the cutting parameters. The objective is to create a relationship between these forces and the surface roughness of the machined edges, once it\'s fundamental to the pipe weld quality. To do this, it was designed and manufactured a dynamometer, and the data was analyzed statistically by the Linear Multiple Regression Method. The results show that for the cutting forces as well as the surface roughness, the most significant parameter is the feed per tooth, followed by the cutting width and the feed speed. These results were successfully proven on the industrial process that is the focus of this study, through the spindle motors electric current and its vibration.

Este trabalho apresenta o desenvolvimento de um microtribômetro linear, do tipo esfera sobre chapa, capaz de analisar o comportamento tribológico de materiais em linhas até 5 mm de comprimento, frequências de até 2 Hz e cargas até 10 N, com ou sem meio úmido, características que o tornam uma ótima ferramenta para observar o comportamento tribológico, ou a resistência ao desgaste de diferentes zonas de uma junta soldada. Durante o projeto do microtribômetro, houve a preocupação de desenvolver um equipamento seguro, fácil de operar e robusto, visando a utilização do mesmo por alunos de graduação e pós-graduação, e na indústria. O trabalho de desenvolvimento compreendeu todas as tecnologias usadas, ou seja, placa de leitura da célula de carga, célula de carga, aparato mecânico responsável pelo movimento da amostra e xação da mesma, braço de suporte do conjunto célula de carga e esfera, carenagem protetora, sistema de segurança e placa de comando. Ensaios foram feitos para a validação do equipamento e demonstrar a capacidade de analisar o comportamento tribológico das diversas zonas de uma junta soldada. / This work presents the development of a linear micro tribometer, sphere over sheet type, capable of analyzing the tribological behavior of materials in lines up to 5 mm in lengh, frenquencies up to 2 Hz and loads up to 10 N, with or without moist enviroment, characteristics that makes it a great tool to observ the diferents regions of a welded joints. During the project there was the concern of developing a secure, easy to operate and robust, aiming it's use by students of gradution, postgraduation and by industry. The development work comprised all the technologies used, reading board of load cell, load cell, mechanical device responsible for moviment and xation of the sample, support arm of the set load cell and sphere, protective cowling, sefety system and board control. Tests have been done to validate the equipment and demonstrate the capacity of analyzing the tribological behavior of the various regions of a welded joint.

The thesis is focused on the technology of scarfing longitudinal welds in welded tubes. The theoretical part describes methods of production tubes. It also analyzes the method used in Mubea company. The experimental part presents the design of two innovative technologies of scarfing welds tubes, their experimental validation and subsequent evaluation. The experimental part also presents a design of the machine that must be produced for this operation.

This thesis deals with the application of simple oxyacetylene welding techniques to the secondary art curriculum. Welded sculptural forms in sheet steel have been the focus of my own work during the past three years and these experiences formed the basis or background of the presentation of these skills to secondary students. An instructional unit was designed to fulfill three primary objectives. First, to familiarize the student with the basic tools and materials used in the construction of welded steel sculpture; second, to introduce the student to the creative concepts involved in the creation of sculptural form; third, to give the student liberal opportunity.to explore the possibilities inherent in the materials.

Welding, as one of the most effective joining methods for metals, has been extensively applied in engineering usage for a long time. When cracks occur in the vicinity of weldments, weld repairs are frequently considered for crack repair to extend service life. In order to evaluate to what extent the weld repair has improved the fatigue life of a cracked welded structure, it is necessary to be able to determine the residual life of the cracked welded joint, as well as the life of the weld repaired joint. Both these assessments require that the fatigue crack growth data be available. The determination of crack propagation rates of welded and weld repaired structures is thus of paramount importance to implement a damage tolerant approach to structural life extension. However, since most studies on welded joints so far have concentrated on fatigue life evaluation, at the present time only limited information is available on crack propagation rates in welded joints, and virtually none on fatigue behaviour and crack propagation in weld repaired joints. This thesis has focused on examination of fatigue and crack propagation behaviour in as welded and weld repaired aluminium alloy 5083, a weldable marine grade alloy extensively used in construction of high speed ferries and aerospace structures. Crack growth rates were measured during constant amplitude fatigue testing on unwelded, as-welded and weld repaired specimens of 5083-H321 aluminium alloy. A 3-D finite element analysis was conducted to determine the stress intensity factors for different lengths of crack taking into account the three-dimensional nature of the weld profile. The effects of crack closure due to weld residual stresses were evaluated by taking measurements of the crack opening displacements and utilised to determine the effective stress intensity factors for each condition. Metallurgical examinations and fractography of the fracture surface were conducted using an optical microscope and SEM. It was found that crack growth rates in welded plates are of the same order of magnitude as those of parent material when effective stress intensity factors were applied. However weld repaired plates exhibit higher crack growth rates compared to those of unwelded and once-only welded plates.

"February, 2004." / Bibliography: leaves 231-249. / xxvii, 261 leaves : ill. (some col.), plates, photos (col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines ways of reducing the risk of hydrogen assisted cold cracking in pipeline construction by modifying the construction procedure to reduce residual stress and hydrogen concentration. A numerical model of the pipeline construction procedure capable of modelling the process in a transient sense was created. Experimental validation of the model involved using the "blind hole drilling" strain gauge method of residual stress measurement. The diffusion of hydrogen during welding was modelled using a scheme based on Fick's Second Law of Diffusion, finding that the parameters which dominate the rate of diffusion are the timing of the weldment process, joint geometry, pre-heating and post-heating. / Thesis (Ph.D.)--University of Adelaide, School of Mechanical Engineering, 2004

Thesis (M.S.) -- Mississippi State University. Department of Mechanical Engineering. / Title from title screen. Includes bibliographical references.

This research evaluated the ethics competencies which were determined to be important to the curriculum of an ethics course for students studying Nondestructive Testing and Welding Inspection. Data were gathered from samples of American Society of Nondestructive Testing Nationally Certified Level III's (N = 268), American Welding Society Nationally Certified Welding Inspectors CWI's (N = 212) and American Welding Society Nationally Certified Associate Welding Inspectors - CAWI's (N = 101) who are currently licensed by their respective societies. The twenty-nine (29) item instrument utilized a six-point Likert type scale for the data collection. The scale, which was validated by consensus using a DELPHI panel procedure, utilized the Hoyt-Stunkard method for assessing reliability. The computed reliability for the instrument was determined to be +0.970. Analysis of variance tests were completed for each of the twenty-nine (29) competencies to ascertain differences between ASNT Level III's, AWS CWI's and AWS CAWI's samples. Factor analysis, using the R-mode, provided for the clustering of competencies and constituted the major analysis procedure for the study. The results of the study indicated the presence of three (3) clusters of content which were considered necessary to curriculum inclusion in an ethics course for nondestructive testing and welding inspection. The identified clusters include: I. Ethical issues and personal integrity (18 competencies), II. Ethics and the legal aspects of inspection (8 competencies), and III. Ethical theory and professional conduct (4 competencies). Overall competency means ranged from 3.929 to 5.594; significance tests showed only five (5) rejected hypotheses for the twent-ynine (29) primary competencies. Standard errors of the mean were found to be lower for the ASNT Level III's sample. The results of the study present a valid pattern for the development of objectives which should be included in an ethics curriculum for nondestructive testing personnel and welding inspectors. / Graduation date: 1993

Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes bibliographical references (p. 229-238).

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-08-20T13:27:19Z No. of bitstreams: 1 EPITÁCIO BRONZEADO NETO - DISSERTAÇÃO (PPGEM) 2018.pdf: 2616160 bytes, checksum: 1b560aacefbd9d94396aeb8e4d0a727c (MD5) / Made available in DSpace on 2018-08-20T13:27:19Z (GMT). No. of bitstreams: 1 EPITÁCIO BRONZEADO NETO - DISSERTAÇÃO (PPGEM) 2018.pdf: 2616160 bytes, checksum: 1b560aacefbd9d94396aeb8e4d0a727c (MD5) Previous issue date: 2018-02-27 / CNPq / O presente estudo documentado neste trabalho buscou investigar a possível correlação existente entre os valores de tenacidade à fratura obtida por meio de ensaios CTOD com a microestrutura da região de grãos grosseiros da região termicamente afetada de juntas do aço API 5L X80, fabricados no Brasil soldados por meio do processo manual e robotizado. Na soldagem manual foi utilizado processo SMAW onde nos passes de raiz foram realizados com eletrodo AWS E9010-G, os passes de preenchimento e acabamento foram realizados com eletrodo AWS E9018-G. Na soldagem robotizada, os passes de raiz foram realizados com processo GMAW e com arame ER120S-G, os demais, passes de preenchimento e acabamento foram realizados com arame tubular AWS E101T-1 tipo flux-cores com proteção gasosa de Ar+25%CO² (FCAW-G) ou AWS E91T8-G com arame auto protegido (FCAW-S). Após as soldagens foram usinados corpos de prova do tipo SE(B) normatizados segundo a ASTM E1820 com entalhe posicionado na região mais propícia a fragilização de acordo com as avaliações da metalográfica e microdureza com intuito de evidenciar o efeito deletério da presença de zonas frágeis (ZF) localizadas nesta região da junta soldada. Foi possível observar que indiferentemente do processo de soldagem houve uma redução significativa na tenacidade à fratura na RGG devido à presença de regiões frágeis constituídas de ilhas de Martensita e Austenita denominadas de microconstituinte AM devido a formação de microtrincas e heterogeneidade microestrutural principalmente no processo manual. Por fim, observou-se que o processo robotizado apresentou melhor repetibilidade e resultados mais favoráveis desde uma melhor distribuição microestrutural, perfil de dureza mais homogêneo e maiores valores de tenacidade à fratura. / The present study investigated the correlation between the fracture toughness values, obtained by CTOD test, with the microstructure of the coarse grains regions of the heat affected zone (HAZ) of API 5L X80 steel welded joints obtained by manual Shielded Metal Arc Welding (SMAW) and by automated Gas Metal Arc Welding Process (GMAW). In the robotized welding, the root passes were made with GMAW process and with ER120S-G wire, the others, composite fill and finishing passages made with AWS E101T-1 type flux-color tubular wire with clay protection Ar + 25% CO² (FCAW-G) or AWS E91T8-G with self-protected wire (FCAW-S). SE(B test specimens standardized according to ASTM E1820 with notch positioned in the most critical regions of the HAZ according to the metallographic and microhardness evaluations in order to evidence the deleterious effect of the fragile zone were done .It was possible to observe that there was a considerable reduction of CTOD value in region with the presence of Austenite and Martensite island nominated AM constituent due to formation of microcracks and microstructural heterogeneity mainly in the manual process. The results also showed that HAZ obtained using the automated GMAW process presented better repeatability, microstructural distribution and CTOD values.