The impact of cooling rate during high-pressure gas quenching on the fatigue performance of low-pressure carburized spur gears was studied for steel grades 20MnCr5 and 17NiCrMo6-4. The results show an increased fatigue limit by 10 to 11% when applying a slower cooling rate for both steel grades. Moreover, for 20MnCr5 the slower cooled gears show an increase in compressive residual stresses by 130 MPa compared to the faster cooling, although no significant difference was observed for 17NiCrMo6-4. It is also seen that the cooling rate affects the core hardness for both steel grades, while other properties like surface hardness, case-hardness depth and martensite variant pairing were unaffected. The results for the retained austenite content and average martensite unit size show no clear effect of the cooling rate. The possible influence of different carbon distributions after quenching for the two used cooling rates on the carbide precipitation and fatigue limit is discussed.

Metal Powder ReportVol. 74, No. 4 Special FeatureManufacturing full density powder metallurgy gears through HIP:ingMichael Andersson, Magnus Bergendahl, Ulf Bjarre, Anders Eklund, Staffan Gunnarsson, Sven Haglund, Hans Hansson, Irma Heikkilä, Alireza Khodaee, Arne Melander, Harald Nyberg, Lars Nyborg, Annika Strondl, Maheswaran Vattur SundaramMichael Andersson⁎Corresponding author. email: E-mail Address: [email protected]aHöganäs AB, SwedenSearch for more papers by this author, Magnus BergendahlbVolvo AB, SwedenSearch for more papers by this author, Ulf BjarrecScania CV AB, SwedenSearch for more papers by this author, Anders EklunddQuintus Technologies AB, SwedenSearch for more papers by this author, Staffan GunnarssoneUddeholm AB, SwedenSearch for more papers by this author, Sven HaglundfSwerim AB, SwedenSearch for more papers by this author, Hans HanssongSwepart Transmission AB, SwedenSearch for more papers by this author, Irma HeikkiläfSwerim AB, SwedenSearch for more papers by this author, Alireza KhodaeehKTH Royal Institute of Technology, SwedenSearch for more papers by this author, Arne MelanderiSwerea KIMAB, SwedenSearch for more papers by this author, Harald NybergcScania CV AB, SwedenSearch for more papers by this author, Lars NyborgjChalmers University of Technology, SwedenSearch for more papers by this author, Annika StrondlfSwerim AB, SwedenSearch for more papers by this author, Maheswaran Vattur SundaramjChalmers University of Technology, SwedenSearch for more papers by this authorMichael Andersson; Magnus Bergendahl; Ulf Bjarre; Anders Eklund; Staffan Gunnarsson; Sven Haglund; Hans Hansson; Irma Heikkilä; Alireza Khodaee; Arne Melander; Harald Nyberg; Lars Nyborg; Annika Strondl; Maheswaran Vattur SundaramPublished Online:30 Sep 2021https://doi.org/10.1016/j.mprp.2018.12.076AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareShare onFacebookTwitterLinked InEmail View article References [1] A. Flodin et al. Metal Powder Report; 72(2); 2017: 107–110. Google Scholar[2] Sundaram M. Vattur et al. Int. J. Adv. Manuf. Technol.; 99(5–8); 2018: 1725–1733. Google Scholar FiguresReferencesRelatedDetails 1 January 2019Volume 74Issue 4ISSN (print): 0026-0657ISSN (online): 1873-4065 Metrics History Published online 30 September 2021 Published in print 1 January 2019 Information© MA Business Ltd.AcknowledgementsThis work was financed by the national agency VINNOVA under contract 2013-05594 within the Programme FFI. The project consisted of the following partners: Chalmers University of Technology, Höganäs AB, KTH Royal Institute of Technology, Leax AB, Quintus Technologies AB, Scania CV AB, Swepart AB, Swerea KIMAB AB, Uddeholm AB and Volvo AB.PDF download

Gear rolling is a forming process to produce gear wheels by plastic deformation. The advantage of the process is to eliminate the chip formation during production and also to improve the product properties since the non-metallic inclusions will be oriented along the cog surface and not perpendicular to it. The method has been developed in the past years for gear production for automobile application with modules up to 3 mm. The successful application of gear rolling in those cases raises the question regarding the feasibility of using cold rolling to manufacture gears with larger modules which can be used for heavy vehicles. In this paper, a gear wheel with normal module of 4 mm has been studied in order to investigate if such large modules can be manufactured by gear rolling. One of the issues in rolling of gears is the design of the blank geometry in order to obtain the right gear geometry after the rolling process. Blank shape modifications are necessary to control and to reduce the undesired shape deviations caused by the large plastic deformations in rolling. The blank modifications also help the process designer to control the forming force and torque. In this paper, the process has been modeled by finite element simulation and the influence of different blanks has been simulated. The validity of the FE model has been checked through several experiments. Both the numerical and experimental results revealed favorable blank modifications to apply for further developments of the gear rolling process.

By utilizing nitriding processes in combination with selection of steel grade manufacturing of components with low friction and high wear properties is facilitated. The need for post machining and ...

In order to meet requirements for lower fuel consumption, low friction powertrain-components are needed. Nitriding and nitrocarburizing are thermochemical heat treatment processes that enhance the ...

Most components are tempered after heat treatment operations such as case hardening orinduction hardening. The common opinion is that the martensitic structure after heat treatmentis too brittle and tempering is necessary to increase toughness.Tempering is an additional operation which leads to increased costs by energy, handling,and investments. Eliminating tempering from the heat treatment process leads to increasedproductivity, energy savings, and lowered environmental impact.Two carburised steels, Ovako 253 and 20NiCrMo2 (AISI 8620, SS2506), were tested forcontact fatigue resistance in a roller to roller rig. The tested samples were characterised withrespect to amount of fatigue damage, residual stress, amount of retained austenite andhardness. The objective was to determine if tempering is always necessary after a heattreatment operation.The contact fatigue tests show that tempering results in lower contact fatigue resistance.