scholarly journals Innovative Densification Process of a Fe-Cr-C Powder Metallurgy Steel

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 665
Author(s):  
Federico Simone Gobber ◽  
Jana Bidulská ◽  
Alessandro Fais ◽  
Róbert Bidulský ◽  
Marco Actis Grande
Keyword(s):  
Heat Treatment ◽  
Powder Metallurgy ◽  
Process Parameters ◽  
Rupture Strength ◽  
Mechanical Resistance ◽  
Metallic Materials ◽  
Transverse Rupture Strength ◽  
Sinter Forging ◽  
Metallurgy Steel ◽  
Main Factor

In this study, the efficacy of an innovative ultra-fast sintering technique called electro-sinter-forging (ESF) was evaluated in the densification of Fe-Cr-C steel. Although ESF proved to be effective in densifying several different metallic materials and composites, it has not yet been applied to powder metallurgy Fe-Cr-C steels. Pre-alloyed Astaloy CrM powders have been ad-mixed with either graphite or graphene and then processed by ESF. By properly tuning the process parameters, final densities higher than 99% were obtained. Mechanical properties such as hardness and transverse rupture strength (TRS) were tested on samples produced by employing different process parameters and then submitted to different post-treatments (machining, heat treatment). A final transverse rupture strength up to 1340 ± 147 MPa was achieved after heat treatment, corresponding to a hardness of 852 ± 41 HV. The experimental characterization highlighted that porosity is the main factor affecting the samples’ mechanical resistance, correlating linearly with the transverse rupture strength. Conversely, it is not possible to establish a similar interdependency between hardness and mechanical resistance, since porosity has a higher effect on the final properties.

scholarly journals Evaluation of the Properties of an Electro-Sinter-Forged Bearing Steel

2020 ◽  
Author(s):  
Róbert Bidulský ◽  
Federico Simone Gobber ◽  
Alessandro Fais ◽  
Jana Bidulská ◽  
Marco Actis Grande
Keyword(s):  
Rupture Strength ◽  
Bearing Steel ◽  
The Other ◽  
Mechanical Resistance ◽  
Metallic Materials ◽  
Experimental Characterization ◽  
Transverse Rupture Strength ◽  
Sinter Forging ◽  
Bearing Steels ◽  
Conventional Press

In this study one of the most innovative sintering techniques up to date was evaluated: Electro-Sinter-Forging (ESF). Despite it has been proved to be effective in densifying several different metallic materials and composites, bearing steels such as 100Cr6 have never been processed so far. Pre-alloyed Astaloy CrM powders have been ad-mixed with either graphite or graphene and then processed by ESF to produce a 100Cr6 equivalent composition. Porosity has been evaluated by optical microscopy and compared to that one of 100Cr6 commercial samples. Mechanical properties such as hardness and transverse rupture strength were tested on samples produced by employing different process parameters and then submitted to different treatments (machining, heat treatment). The experimental characterization highlighted that porosity is the factor mostly affecting mechanical resistance of the samples, correlating linearly to the transverse rupture strength. Hardness on the other side does not correlate to the mechanical resistance because process related cracking has a higher effect on the final properties. Promising results were obtained that give room to the sinterability by ESF of materials difficult to sinter by conventional press and sinter techniques.

Transverse Rupture Strength of M3:2 High Speed Steel Produced through Conventional Casting and Powder Metallurgy Techniques

2006 ◽  
Vol 514-516 ◽  
pp. 584-588
Author(s):  
Oscar O. Araujo Filho ◽  
João Franklin Liberati ◽  
Waldemar Alfredo Monteiro ◽  
Maurício David Martins das Neves ◽  
Luís Carlos Elias da Silva ◽  
...  
Keyword(s):  
Heat Treatment ◽  
High Speed ◽  
Rupture Strength ◽  
Hot Isostatic Pressing ◽  
High Speed Steel ◽  
Liquid Phase Sintering ◽  
Bending Tests ◽  
Transverse Rupture Strength ◽  
Three Point Bending ◽  
Hardness Tests

The main aim of this work is to study the influence of the heat treatment on the transverse rupture strength of three M3:2 high speed steel obtained by differents techniques. PM Sinter 23 obtained by hot isostatic pressing (HIP) of gas atomized powders, a vacuum sintered high speed steel obtained by uniaxial cold compaction and liquid phase sintering of M3:2 water atomized powders and a conventional (cast to ingot and hot work) VWM3C were submitted to hardening in order to determine the influence of this treatment on the transverse rupture strength. The two PM high speed steels and the conventional one were submitted to heat treatment of hardening with austenitizing temperatures of 1140, 1160, 1180 and 1200 °C and tempering at 540 and 560 °C. The effectiveness of the heat treatment was determined by hardness tests (Rockwell C hardness). The microstructure was evaluated by scanning eletronic microscopy (SEM). At least five samples of these three high speed steels were manufactured, austenitized, quenched and tempered as described above and fractured in three point bending tests in order to evaluate the influence of this treatment on the transverse rupture strength (TRS).

Effect of Nano-Carbides on the Microstructure and Mechanical Properties of Ti(C,N)-Based Cermets

2011 ◽  
Vol 105-107 ◽  
pp. 2071-2075
Author(s):  
Yan Lei ◽  
Jing Fu Liu ◽  
Bing Yang
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Formation Mechanism ◽  
Ostwald Ripening ◽  
Rupture Strength ◽  
The Other ◽  
Homogeneous Microstructure ◽  
Heterogeneous Microstructure ◽  
Transverse Rupture Strength ◽  
Black Core

In this paper, Ti(C,N)-Based cermets with addition of nano-carbides were fabricated by conventional powder metallurgy techniques. Then the mechanical properties, microstructure and corresponding formation mechanism have been investigated. According to the results, the microstructures of sintered cermets are composed of three kinds of hard grains: one with black core/grey shell, one with white core , and the other with no core. In addition, with more nano-carbides adding, the number of white core grains increases and that of black core grains decreases. It is also found that sintered cermets with nano-carbide additions exhibit higher transverse rupture strength and higher hardness than the others originated from much finer and more homogeneous microstructure. However, cermets with nano-micro carbide additions show the most poor mechanical properties among all sintered cermets, including conventional cermets, due to the obviously heterogeneous microstructure. And this can be explained by Ostwald ripening theory.

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