Title: A comparative study on the dry sliding wear behaviour of nitrocarburised, gas nitrided, fluidised-bed nitrided, and plasma nitrided plastic mould steel

Authors: E. Boztepe; A.C. Alves; A. Ramalho; E. Ariza; L.A. Rocha; N. Cansever; F. Toptan

Addresses: Faculty of Chemistry and Metallurgy, Department of Metallurgical and Materials Engineering, Yildiz Technical University, Davutpasa Campus, 34210 Esenler, Istanbul, Turkey; Centre of Microelectromechanical Systems (CMEMS-UMinho), Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal ' Dept. Eng. Mecânica, Azurém, Centre of Microelectromechanical Systems (CMEMS-UMinho), Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal ' CEMUC – Department of Mechanical Engineering, University of Coimbra, 3030 Coimbra, Portugal ' Centre of Microelectromechanical Systems (CMEMS-UMinho), Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal; Universidade do Minho, SEMAT/UM, Azurém, 4800-058 Guimarães, Portugal ' Centre of Microelectromechanical Systems (CMEMS-UMinho), Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal; Dep. Física, Faculdade de Ciências de Bauru, UNESP – Univ. Estadual Paulista, 17033-360 Bauru, SP, Brazil ' Faculty of Chemistry and Metallurgy, Department of Metallurgical and Materials Engineering, Yildiz Technical University, Davutpasa Campus, 34210 Esenler, Istanbul, Turkey ' Centre of Microelectromechanical Systems (CMEMS-UMinho), Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal; Dept. Eng. Mecânica, Universidade do Minho, Azurém, 4800-058 Guimarães, Portugal

Abstract: Plastic injection moulds suffer wear due to the relative movements of the mould parts and the polymeric material flow which is often reinforced by hard abrasive fibres or whiskers. Several studies were performed on the wear behaviour of diverse nitrided surfaces; however, comparative studies are needed. The present study aims to compare the dry sliding wear behaviour of nitrocarburised, gas-nitrided, fluidised-bed nitrided, and plasma-nitrided Impax Supreme (equivalent to AISI P20) pre-hardened plastic mould steel. The wear tests were performed against AISI 4140 pins under 100 N normal loads, with the total stroke length of 10 mm, the frequency of 1.5 Hz, and the total sliding distance of 400 m. After tests, worn surfaces and wear debris were microstructurally and chemically characterised and the wear rates were calculated. Results suggested that all samples presented mainly combination of adhesive and abrasive wear during the run-in period of sliding (severe wear), and mainly oxidative wear during the steady-state of (mild wear). Although no significant difference was observed between the treated samples, plasma-nitrided samples presented the lowest wear rate as mean values.

Keywords: gas nitriding; nitrocarburising; plastic mould steel; dry sliding wear; fluidised bed nitriding; plasma nitriding; injection moulding; microstructure; wear rate; adhesive wear; abrasive wear.

DOI: 10.1504/IJSURFSE.2016.079044

International Journal of Surface Science and Engineering, 2016 Vol.10 No.5, pp.468 - 484

Received: 21 May 2015
Accepted: 17 Jul 2015

Published online: 10 Sep 2016 *

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