Influence of lubrication, tool steel composition, and topography on the high temperature tribological behaviour of alumi
- PDF / 6,535,605 Bytes
- 14 Pages / 595.22 x 790.976 pts Page_size
- 36 Downloads / 195 Views
ISSN 2223-7690 CN 10-1237/TH
RESEARCH ARTICLE
Influence of lubrication, tool steel composition, and topography on the high temperature tribological behaviour of aluminium Justine DECROZANT-TRIQUENAUX 1,*, Leonardo PELCASTRE1, Braham PRAKASH1,2, Jens HARDELL1 1
Machine Elements, Luleå University of Technology, Luleå SE-97187, Sweden
2
Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
Received: 12 September 2019 / Revised: 11 December 2019 / Accepted: 12 February 2020
© The author(s) 2020. Abstract: The use of high strength aluminium alloys, such as 6XXX and 7XXX series, is continuously increasing for automotive applications in view of their good strength-to-weight ratio. Their formability at room temperature is limited and they are thus often formed at high temperatures to enable production of complex geometries. Critical challenges during hot forming of aluminium are the occurrence of severe adhesion and material transfer onto the forming tools. This negatively affects the tool life and the quality of the produced parts. In general, the main mechanisms involved in the occurrence of material transfer of aluminium alloys at high temperature are still not clearly understood. Therefore, this study is focussed on understanding of the friction and wear behaviour during interaction of Al6016 alloy and three different tool steels in as-received and polished state. The tribotests were carried out under dry and lubricated conditions, with two distinct lubricants, using a reciprocating friction and wear tester. The worn surfaces were analysed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed a high dependence of friction and wear behaviour on the tool steel roughness as well as on the stability of the lubricant films. Tribolayers were found to develop in the contact zone and their capacity to improve the tribological behaviour is seen to be drastically impacted by the surface roughness of the tool steel. When the tribolayers failed, severe adhesion took place and led to high and unstable friction as well as material transfer to the tool steel. Keywords: friction; wear; high temperature tribology; aluminium; lubrication; tribolayer
1
Introduction
In order to comply with the increasingly stringent emission regulations, passenger safety, as well as the considerations of added weight of e.g. batteries for electric vehicles, the automotive industry is turning towards the use of materials with high strength-to-weight ratio. High strength aluminium alloys, such as the 6XXX and 7XXX series, are examples of materials that can meet these demands. Novel lightweight design solutions can be realised by combining high-strength steel and aluminium
into the body-in-white structure of passenger cars. In order to manufacture complex shaped components, hot forming of aluminium is usually the preferred production method [1]. Forming at high temperature minimises spring-back [2] and improves formability compared to cold forming [3, 4]. High tempera
Data Loading...
