TY - JOUR

T1 - Development of a procedure for forming assisted thermal joining of tubes

AU - Chen, Hui

AU - Löbbe, Christian

AU - Staupendahl, Daniel

AU - Tekkaya, A. Erman

N1 - Conference code: 21

PY - 2018/5/2

Y1 - 2018/5/2

N2 - With the demand of lightweight design in the automotive industry, not only the wall-thicknesses of tubular components of the chassis or spaceframe are continuously decreased. Also the thicknesses of exhaust system parts are reduced to save material and mass. However, thinner tubular parts bring about additional challenges in joining. Welding or brazing methods, which are utilized in joining tubes with specific requirements concerning leak tightness, are sensitive to the gap between the joining partners. Furthermore, a large joining area is required to ensure the durability of the joint. The introduction of a forming step in the assembled state prior to thermal joining can define and control the gap for subsequent brazing or welding. The mechanical pre-joint resulting from the previously described calibration step also results in easier handling of the tubes prior to thermal joining. In the presented investigation, a spinning process is utilized to produce force-fit joints of varying lengths and diameter reduction and form-fit joints with varying geometrical attributes. The spinning process facilitates a high formability and geometrical flexibility, while at the achievable precision is high and the process forces are low. The strength of the joints is used to evaluate the joint quality. Finally, a comparison between joints produced by forming with subsequent brazing and original tube is conducted, which presents the high performance of the developed procedure for forming assisted thermal joining.

AB - With the demand of lightweight design in the automotive industry, not only the wall-thicknesses of tubular components of the chassis or spaceframe are continuously decreased. Also the thicknesses of exhaust system parts are reduced to save material and mass. However, thinner tubular parts bring about additional challenges in joining. Welding or brazing methods, which are utilized in joining tubes with specific requirements concerning leak tightness, are sensitive to the gap between the joining partners. Furthermore, a large joining area is required to ensure the durability of the joint. The introduction of a forming step in the assembled state prior to thermal joining can define and control the gap for subsequent brazing or welding. The mechanical pre-joint resulting from the previously described calibration step also results in easier handling of the tubes prior to thermal joining. In the presented investigation, a spinning process is utilized to produce force-fit joints of varying lengths and diameter reduction and form-fit joints with varying geometrical attributes. The spinning process facilitates a high formability and geometrical flexibility, while at the achievable precision is high and the process forces are low. The strength of the joints is used to evaluate the joint quality. Finally, a comparison between joints produced by forming with subsequent brazing and original tube is conducted, which presents the high performance of the developed procedure for forming assisted thermal joining.

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=85047319414&partnerID=8YFLogxK

U2 - 10.1063/1.5034879

DO - 10.1063/1.5034879

M3 - Conference article in journal

AN - SCOPUS:85047319414

VL - 1960

JO - AIP Conference Proceedings

JF - AIP Conference Proceedings

SN - 0094-243X

IS - 1

M1 - 050006

T2 - 21st International European Scientific Association Conference on Material Forming - ESAFORM 2018

Y2 - 23 April 2018 through 25 April 2018

ER -