Tre metoder att behandla restpänningar i bakaxelbryggor: Ur ett produktions och hållfasthetsperspektiv
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
This master thesis is a continuation on previous theses that are trying to find a best solutionfor a problem at Ferruform AB, the last one written by Jonas Holmgren and Stefan Lindqvistin 2007.When Ferruform AB cold form and weld their rear axle housings (RAHs) unwanted residualstresses build up in the material. This affects the form stability and fatigue life of thecomponents and is today dealt with by heat stress relief. Heat stress relief is both a time andan energy consuming method which Ferruform wants to exchange to a method that fitbetter into their manufacturing line.In this work the two alternative methods Vibratory Stress Relief (VSR) and Bend-Straightening (BS) have been evaluated by comparing them to the heat stress relieving (HSR)method and untreated components (noHSR). They have been evaluated on how they affectthe form stability of the axle and how well they fit into Ferruforms production.Production:• Concepts have been done to see how the different alternatives would fit intoFerruforms factory.• The concepts have been evaluated in the areas that Ferruform put value in.Form stability:• A total of 24 rear axle housing have been exposed to each of the different methods,six to each.• All axles have been exposed to a repeated load for ten cycles, and then the alignmentof the axle ends compared to before loading have been investigated.The results from this study were that the BS method is superior to HSR and VSR. Both from aproduction and a form stability point of view.Production:• A concept with one BS machine parallel to the oven that can be evolved into anautomatic robot station with two machines and no oven was the best option.Form stability:• The BS method work as well as the HSR method in a form stability aspect while theRAHs treated with VSR failed to live up to the requirements and behaved similarly tothe untreated RAHs.The recommendation based on this work is to look further into the BS method and startingwith a full fatigue test to see if it works as well as HSR in a fatigue perspective as well.
Place, publisher, year, edition, pages
2012. , 125 p.
Teknik, restspänningar, vibratory stress relief, avspänningsglödgning, Ferruform
IdentifiersURN: urn:nbn:se:ltu:diva-51307Local ID: 883718d8-be1e-4de1-85a2-3d17001136a5OAI: oai:DiVA.org:ltu-51307DiVA: diva2:1024668
Subject / course
Student thesis, at least 30 credits
Engineering Physics, master's level
Validerat; 20120328 (anonymous)2016-10-042016-10-04Bibliographically approved