• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.75-81
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• 2011

Dissimilar joining of aluminum 6061-T6 alloy to aluminum 5083-O alloy was performed using friction-stir welding technique. The mechanical properties, hardness, macro- and micro-structure on dissimilar friction-stir-weld aluminium alloy were investigated. Mechanical properties of the weld mainly depend on which Al alloy is placed at the retreating sides of the rotating tool respectively during dissimilar friction-stir weld because the microstructure of stir zone was mainly composed of welded Al alloys of the retreating side. Onion ring pattern was observed like lamella structure stacked by each Al alloy in turn. It apparently results in defect-free weld zone that traverse speed was changed to 124 mm/min under conditions of tool rotation speed like 1250 rpm with 5 mm of tool's prove diameter, 4.5 mm of prove length, 20 mm of shoulder diameter, and $2^{\circ}$ of tilting angle. The 231 MPa of ultimate stress and the 121 MPa of yield point are obtained about the friction-stir-welded Al 6061-T6(AS) to Al 5083-O(RS).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.85-90
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• 2010

Friction welding is a common practice to join axially symmetrical parts for automobile industry applications. The shaft for automobile reverse idle gear is generally produced by forging steel, SF 45. This method is not so good because of high cost of material and production. In this study, in order to investigate the possibility of application of SM 45C to SF 45 dissimilar friction welding, the dissimilar friction welded joints were performed using 20 mm diameter solid bar in forging steel(SF 45) to carbon steel(SM 45C). The optimal friction welding parameters were selected to ensure reliable quality welds on the basis of visual examination, tensile test, micro-Virkers hardness surveys of the bond of area and optical microstructure investigations for welded joint parts. Finally, post weld heat treatment(PWHT) of the high-frequency induction hardening was performed for the friction welded specimens under the optimal welding conditions. And then, the mechanical properties were compared for as-welded and PWHT in SM 45C to SF 45.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.75-81
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• 2012

Dissimilar material friction welding such as STD11 and SCM440, we are considering of such things as strength and tenacity of welding interface, which consist of friction welding rotation frequency, friction heating pressure, upset forging-pressure, friction heating time, and upset forging-pressure time. From the study, obtaining the interrelationship between welding condition and quality(toughness, tenacity), we can set the best range of welding condition. while performing acoustic emission examination for the nondestructive evaluation, we can deduce the interrelationship among total acoustic emission counts, friction welding variable, and quality during friction welding, which can solve the manufacturing difficulty and enhance the economic value.

• Journal of Ocean Engineering and Technology
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• v.10 no.3
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• pp.24-33
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• 1996

Up to now, most of studies on mechanical properties in friction welded components are about tensile and bending strength. However the fatigue studies on the friction-welded components subjected to repeated stress are not available. The purposes of this study are the development of fundamental design and the development of in-process real-time weld quality evaluation technique by acoustic emission for the bar-to-bar dissimilar friction welding of hydraulic valve spool steels.

• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.1-10
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• 1999

The engine exhaustive valve became essential as the important element. The dissimmilar welding method of exhaustive valve head to stem was asked for manufacturing the engine exhaustive valve, for which the electric resistance are welding has been conventionally used, resulting in poor quality of the welded joint. In this paper, not only the development of optimizing of friction welding with more reliability and more applicability but also the development of in-process real-time weld qudlity(such as strength and toughness) evaluation technique by acoustic emission for friction welding of the engine exhaustive valve(SUH3-SUH35 dissimilar steels) were perfomed. The high temperature(500, 500, 600$^{circ}$C) creep properties prediction of the friction welded joint of SUH3-SUH35 was investigated relating to the initial strain meethod(ISM) as a new approach, resulting in obtaining an experimental equation of creep life prediction.

• Journal of Ocean Engineering and Technology
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• v.13 no.3 s.33
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• pp.77-82
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• 1999

The compleete joining method for dissimilar hot die punch materials and its real-time evaluation method are not available at present. Brazing method has been used for joining them, but it is known that the welded joint by the brazing has the lower bonding efficiency and reliability than the diffusion welding. The friction wleding with a diffusion mechanism in bonding was applied in this study. So, this work was carried out to determine the optimal friction welding conditions and to analyze mechanical properties of friction welded joints of hot die punch materials (STD61 for the blade part of hot die punch) to alloy steel (SCM440 for the shank park of hot die punch) such as plunger. In addition, acoustic emission test was carried out during friction welding to evaluate the weld quality.

• Journal of Power System Engineering
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• v.6 no.1
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• pp.68-73
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• 2002

An opportunity to use the elevated temperature has been recently increasing in various elements of heat facilities or machines such as heat exchanger tubes, pressure vessels, engines of aircraft, boilers and turbines in power plants, and nuclear reactor components, etc. as machinery industry develops. Thus, the development of such elevated-temperature heat-resisting materials and the studies on their elevated-temperature materials friction welding, creep design and analysis have been considered as an important and needful fact. In this paper, friction welding optimization for 1Cr0.5Mo to STS304 and AE applications for the weld quality evaluation were investigated. The important results of this study are as follows : The techniques for dissimilar friction welding optimization of the elevated temperature materials 1Cr0.5Mo and STS304 and its real-time weld quality evaluation by AE were developed, considering on both strength and toughness. Quantitative relationship was identified among welding condition, weld quality and cumulative AE counts.

• Journal of Ocean Engineering and Technology
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• v.11 no.1
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• pp.24-35
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• 1997

The hydraulic or pneumatic valve spools become essential as the important components on the production of automatic hydraulic or pneumatic as mechanical industry has been rapidly developed. The machining precision is in necessity for manufacturing the valve spools. They could be unstable in the quality by the conventional are welding. And also they have a lot of technical problems in manufacturing because their shapes are generally small. By the precision casting process such as lost wax process, the production cost may be increased. But by the friction welding technique, they will be able to be manufactured without such problems. This paper deals with the development of dissimilar friction welding optimization for the hydraulic or pneumatic valve spool by friction welding and a new approach of on real-time qualify evaluation by AE techniques.

• Journal of Ocean Engineering and Technology
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• v.1 no.1
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• pp.138-143
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• 1987

Friction welding has emerged as a reliable process for high-production commercial applications with significant economic and technical advantages. But nondestructive test in friction weld was not clearly developed. Therefore the experimental verification is necessary in order to understand the characteristcs of the pulse echo effects according to various change in welding conditions. This paper presents an attempt to determine the relationship between the varios welding conditions and the coefficients of reflection using the ultrasonic pulse echo method in dissibilar metals friction weld. The new approach of calculating the coefficients of reflection based on measured amplitudes of the echoes is applied in this paper. These coefficients provides a single quantitative measurement which involves both acoustic energy reflected at the welded interface as well as transmitted across the interface. As a result, it was known that the quantitave relationship between welding conditions and the coefficients of reflection using the ultrasonic pulse echo exists in dissimilar metals friction weld.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.3
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• pp.29-35
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• 2020

This paper studies the main parameters of tube-to-bar dissimilar material and shape friction welding for piping materials. The weldability of joint parts was investigated with respect to tensile tests, micro-Vickers hardness, the bond of area, and optical microstructure. The specimens are tested as-welded. Optimal welding conditions are n = 2000 rpm, HP = 50 MPa, UP = 100 MPa, HT = 5 sec, and UT = 10 sec when the metal loss (Mo) is 11 mm. Moreover, the same two materials for friction welding are strongly mixed with a well-combined structure of micro-particles without any molten material, particle growth, or defects. Therefore, the expected result of dissimilar material friction welding includes a reduction of cost and material in the welding process.