<abstract xmlns="http://www.w3.org/1999/xhtml">In order to be cost effective and to meet increasing performance demands, powder metallurgy steel components require continuous improvement in terms of materials and process development. This study demonstrates the feasibility of manufacturing structural components using two different alloys systems, i.e. lean Cr-prealloyed and diffusion bonded water atomised powders with different processing conditions. The components were sintered at two different temperatures, i.e. 1120 and 1250 °C for 30 minutes in three different atmospheres: vacuum, N2- 10%H2 atmosphere as well as lean N2-5%H2-0.5%CO-(0.1-0.4)%CH4 sintering atmosphere. Components after sintering were further processed by either low pressure carburizing, sinterhardening or case hardening. All trials were performed in the industrial furnaces to simulate the actual production of the components. Microstructure, fractography, apparent and micro hardness analyses were performed close to the surface and in the middle of the sample to characterize the degree of sintering (temperature and atmosphere) and the effect of heat treatment. In all cases, components possess mostly martensitic microstructure with a few bainitic regions. The fracture surface shows well developed sinter necks. Inter- and trans-granular ductile and cleavage fracture modes are dominant and their fraction is determined by the alloy and processing route.</abstract>

In order to be cost effective and to meet increasing performance demands, powder metallurgy steel components require continuous improvement in terms of materials and process development. This study demonstrates the feasibility of manufacturing structural components using two different alloys systems, i.e. lean Cr-prealloyed and diffusion bonded water atomised powders with different processing conditions. The components were sintered at two different temperatures, i.e. 1120 and 1250 °C for 30 minutes in three different atmospheres: vacuum, N2- 10%H2 atmosphere as well as lean N2-5%H2-0.5%CO-(0.1-0.4)%CH4 sintering atmosphere. Components after sintering were further processed by either low pressure carburizing, sinterhardening or case hardening. All trials were performed in the industrial furnaces to simulate the actual production of the components. Microstructure, fractography, apparent and micro hardness analyses were performed close to the surface and in the middle of the sample to characterize the degree of sintering (temperature and atmosphere) and the effect of heat treatment. In all cases, components possess mostly martensitic microstructure with a few bainitic regions. The fracture surface shows well developed sinter necks. Inter- and trans-granular ductile and cleavage fracture modes are dominant and their fraction is determined by the alloy and processing route.

Effect of Alloying Type and Lean Sintering Atmosphere on the Performance of PM Components

Department of Industrial and Materials Science

Powder Metallurgy Progress

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

In order to be cost effective and to meet increasing performance demands, powder metallurgy steel components require continuous improvement in terms of...

Effect of Alloying Type and Lean Sintering Atmosphere on the Performance of PM Components

Publié en ligne: 01 mars 2018

Pages: 72 - 81

DOI: https://doi.org/10.1515/pmp-2017-0008

Mots clés
lean alloyed PM steels, lean sintering atmospheres, low pressure carburizing, sinterhardening, case hardening

© 2017 M. Vattur Sundaram et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Effect of Alloying Type and Lean Sintering Atmosphere on the Performance of PM Components

Publié en ligne: 01 mars 2018

Pages: 72 - 81

DOI: https://doi.org/10.1515/pmp-2017-0008

Mots cléslean alloyed PM steels, lean sintering atmospheres, low pressure carburizing, sinterhardening, case hardening

© 2017 M. Vattur Sundaram et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Mots clés
lean alloyed PM steels, lean sintering atmospheres, low pressure carburizing, sinterhardening, case hardening