No Abstract, See Full Text

Welding is critical technique for the joining of materials in the nation's major Manufacturing industries. Since 1998, leaders in welding industry have defined a vision of the issues and opportunities that it will face in 2020. In developing this vision document, more than 25 senior managers and respected experts from various segments of the welding community met to begin a dialog about the future of the welding industry. They were brought together to develop a long-range business plan for their industry that would identify how it would meet the needs of manufacturers, of the marketplace, and of society in 2020. In essence, these decision makers created an ideal vision of the state of their industry in 20 years, and the strategy to reach it. Welding is a precise, reliable, and cost-effective, method for joining materials. No other technique is as widely used by manufacturers to join metals and alloys efficiently. Most of the familiar objects in modern society, form buildings and bridges, to vehicles, computers, and medical devices, could not be produced without the use of welding. Despite the importance of welding to the manufacturing industry, the leaders in this area felt that welding was not appreciated as much as it should be from the society. The welding industry consists of the “users” of welding techniques as well as the companies, universities and other organizations that industry look for improvements in their operations by 2020, and should find their interest addressed in this document. A major economic impact study co sponsored by AWS and EWI and supported by US Navy, State of Ohio, US Department of Commerce, and major companies was kicked off. This two-year study will determine the economic impact of welding on the United States economy. The objective of this study is to break a paradigm about welding-those of us who are heavily involved in welding, believe strongly that much of our gross domestic product is directly dependent on welding. Furthermore, continued advances in the field of welding are necessary to achieving further increases in productivity that makes our economy strong. Yet, despite intuition, anecdotal information, and fragmented analyses, the completing quantitative information that would proved the justification for strategic actions to further develop this critical field is not currently available.

Welding processing is used in the various industrial fields such as shipbuilding, car, airplane and steel structure, etc.. But the welding process has a bad working condition and lack of skillful worker. The welding depended on man power causes low productivity and difficulty in keeping continuous and stable quality control. This paper shows the development results of welding mobile robot with the several functions such as continuous/intermittent welding, initial welding speed control, acceleration control, crater and deceleration speed control in welding end. The robot is developed based on microprocess which is intel 80c196kc.

It is difficult to realize automation of welding of lattice type in shipbuilding and assembly processing of shipbuilding and steel structures. Usually, the welding parts of lattice type are welded manually. So there are limitations in continuous and stable quality controls and in increase in productivity because the welding quality depends on worker's skill. That is, automation in welding is necessary. This paper shows shows the development results of a moblie robot for welding of lattice type. Specially. algorithms for its mobile speed and seam tracking controls are introduced.

This paper presents a new method of segmenting a one-dimensional signal into a set of features of type(line, Vee-groove, Lap-joint and etc.), A set of requirements for the segmentation process result from the application area, which in this case are laser welding, GMAW(Gas Metal Arc Welding), SAW(Submerged Arc Welding) and high speed tack welding. The algorithm is able to detect an exact welding position in the presence of noise and missing data, yet is reasonably economical to implement

Resistance Spot Welding has been one of the important process in the sheet metal fabrication of auto-body industry It is well known that the nugget formation of RSW is the major factor for the strength of the body. A high speed camera was used to consider initial melting and growth of the weld nugget in order to find out the nugget formation mechanism. It was observed that such mechanism had an effect on the dynamic resistance, which was a process parameter of resistance spot welding. Also, the relationship between the mechanism and process parameter was considered for the industrial application.

Residual stress is generated in the structures as a result of irregular elastic-plastic deformation during fabrication processes such as welding, heat treatment, and mechanical processing. There are several factors attributed to the origin of residual stresses, tensile or compressive. The stresses can be determined by destructive ways or nondestructive ways by using X-ray or neutron diffraction. This paper presented application of neutron diffraction technique to the residual stress measurement using 20 mm thick welded stainless steel plate(100$\times$100 $\textrm{mm}^2$)

The fatigue crack propagation characteristics were investigated for two kind of heat-resisting steel(STR3 and STR35) commonly using in valve material of vehicles. From the experiment, the fatigue life of the specimens notched at bonded line was shown about 19.7％ and 72.2％ lower and the specimens notched at 1.0mmdistance from bonded line was shown about 25.2％ and 99.1％ higher than that of the base metal respectably.

This paper presents a study on the LD Pump laser welded heat transfer and distortion analysis by using finite element method. In the production processing, ferrule and saddle of LD Pump in light-wave communication system are welded by multi mode Nd-YAG laser. Thus distortion happens during laser-welded packaging, and it makes an error of detecting the light signal translated through optical fiber in LD Pump. These parts experience thermal and mechanical hysteresis during heating and cooling process come from laser welding. The amount of final displacement is predicted using the finite element method. And the optimal shape is decided by using the result of pre-analysis.

In this research, newly proposed heat source equations were calculated to predict micro distortion of small structure in laser welding and compared with experimental results which were measured using laser speckle metrology. A finite element code, ABAQUS is used for the heat transfer analysis with a three-dimensional plane assumption. The results suggest that weld distortion is varied according to the heat source of the. laser beam.

This paper describes a fundamental investigation of the friction welding condition for pure copper/pure titanium and the effect of friction time, upset pressure on the mechanical and metallurgical properties of friction welding. Under the constant upset pressure, the tensile strength make a little difference with an increase in friction time. At the constant friction time, the tensile strength increased with an increase in upset pressure. The tensile fracture of Cu to Ti joint occurred in Cu base material near interface.

In this study, effect of welding parameters on the defect density in the weldments produced by high frequency electric resistance welding process. The defect density measured by X-ray radiography showed a W-type curve as a function of heat input rate. The mechanisms of the such behavior were discussed based on the chemical compositions of the oxides formed at the weldments.

In case of hardfaced wrapping roll, beadmark shape appear at wrapping roll surface due to irregular wear between weld bead. Irregular wear of this is caused by difference of hardness between weld bead. This study aims at investigating which matrix is good for removing of beadmark at wrapping roll surface. So, we make specimen with martensitic matrix and austenitic matrix. The hardfacing alloys were deposited 4 times on a SS41 steel plate using self-shielding flux cored arc welding method. Difference of hardness between weld bead of specimen with matrix of martensite was higher than specimen with matrix of austenite both as-welded and after heat treatment. Therefore, austenitic matrix is better than martensitic matrix for removing of beadmark of wrapping roll surface.

This study was investigated absorption properties of electromagnetic wave in thermal sprayed Sr-ferrite coatings. The experiment of this study was ; manufactured thermal spraying powder for improving absorption-efficiency, processed for increasing strength of thermal spray coatings, and measured the electromagnetic wave shielding efficiency. This study was obtained excellent absorption-efficiency by thermal sprayed Sr-ferrite coatings.

High viscosity mixing powder is a very useful material for laser cladding. This material has a high viscosity so that it can be sticked to substrate. Therefore, Laser cladding can be performed on a curved or slope surface. Laser cladding can be easily performed with the material instead of wire that is difficult to be manufactured in some case. In this experiment, it was used a high viscosity mixing powder which consists of a high temperature flux and a bronze powder. And AC2B alloy material was used as a substrate. Flux prevents the clad layer from being oxidized and increases bonding property between substrate and cladding material. It makes possible to laser cladding at low level energy.

A methodology is developed and many used to evaluate the response sensitivity of the thermal systems to variations in their design parameters. Technique for computing the sensitivity of temperature distributions to changes in processing parameters needed for deciding the more effective laser input parameters for laser surface hardening treatment are considered. In this study, a state equation governing the heat flow in laser surface treatment is analyzed using a three-dimensional finite element method and sensitivity data of the processing parameter obtained using a direct differentiation method applied for sensitivity analysis. The interesting processing parameter is taken as the laser scan velocity and characteristic beam radius( $r_{b}$) of the sensitivity of the temperature T versus v and $r_{b}$ is analyzed. And these sensitivity results obtained in another parameters are fixed condition. To verifying the numerical analysis results, hardened layer dimensions (width and depth) of the numerical analysis compared with the results of an experimental data.ata.