Title: A study of the strengthening mechanisms in the novel precipitation-hardening KeyLos® 2001 steel

Authors: M. Faccoli, A. Ghidini, R. Roberti

Addresses: Department of Mechanical Engineering, University of Brescia, via Branze 38, 25123 Brescia, Italy. ' Lucchini Sidermeccanica S.p.A., via Giorgio Paglia 45, 25063 Lovere (BG), Italy. ' Department of Mechanical Engineering, University of Brescia, via Branze 38, 25123 Brescia, Italy

Abstract: KeyLos® 2001 is a new precipitation-hardening steel especially developed for plastic moulds. In this study the precipitation stage of KeyLos® 2001 steel has been investigated and compared to the results obtained with 17-4 PH steel. Precipitation-hardening has been carried out at three different temperatures and the stages of hardening and overageing have been studied in order to clarify the hardening mechanisms. It has been found that hardening and softening mechanism during the precipitation-hardening treatment occur at higher temperatures and in correspondence with more prolonged treatment times than those typical for the best known 17-4 PH steel; hardness is then expected to remain stable also for very extended mould lives. Microstructural investigations by means of Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) have also been carried out and the microstructural parameters responsible for the hardening and overageing have been pointed out.

Keywords: plastic moulds; mould steels; strengthening mechanisms; precipitation hardening steel; age hardening treatment; primary carbides; microstructure; overageing.

DOI: 10.1504/IJMMP.2008.018757

International Journal of Microstructure and Materials Properties, 2008 Vol.3 No.2/3, pp.424 - 438

Available online: 16 Jun 2008 *

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