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ASTM Selected Technical Papers
Bearing and Transmission Steels Technology
Editor
John Beswick
John Beswick
Symposium Chair and STP Editor
1Montfoort,
SE
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ISBN:
978-0-8031-7745-1
No. of Pages:
558
Publisher:
ASTM International
Publication date:
2024

Increasing power density and rotational speed raise major challenges for transmission development, especially in the field of aerospace technology and electromobility. Both the increase in energy input and the decrease in capability of heat dissipation lead to an increase in the operating temperature of high-performance transmissions. As a result of this increase in operating temperature, the microstructures of conventional bearings and gears are exposed to tempering, which can reduce the load capacity of these components. Especially for gear applications, a complex load capacity profile is needed, since the gears have to resist high contact pressure on the tooth flank and high bending stress in the tooth root. Considering the increase in operating temperatures, it is only permissible to manufacture the gears in high-performance transmissions from heat-resistant and high-performance materials. It is mandatory to achieve the necessary high-performance by heat treatment of gears. Today high-performance gears are typically case-hardened to achieve the best performance in service. Due to the metastable characteristics of martensite, the microstructure of a gear can degrade during service if the operating temperature meets or exceeds the former tempering temperature. This degradation leads to reduced hardness and a decrease in performance. To achieve a more stable state of microstructure prior to service, new heat treatments and alternative steel grades are continuously being developed. The aim of this paper is to investigate the strength of gears made out of the recently developed Hybrid 55 material (EN X20NiCrAlMoV6-5-2-1) and to compare the performance of these gears with commonly employed gears that are made out of EN20MnCr5 material. Initially various carburizing and nitriding treatment variants were used for heat treatment of the gears, and then the gears were tested for tooth root strength at 180°C in a newly developed test rig.

1.
Hayrynen
K.
,
Brandenberg
K.
, and
Keough
J.
,
Carbo-Austempering: A New Wrinkle?
(
Warrendale, PA
:
SAE International
,
2002
),
2.
Zhang
P.
,
Zhang
F. C.
,
Yan
Z. G.
,
Wang
T. S.
, and
Qian
L. H.
, “
Wear Property of Low-Temperature Bainite in the Surface Layer of a Carburized Low Carbon Steel
,”
Wear
271
, nos.
5–6
(
2011
): 697–704,
3.
Zhang
P.
,
Zhang
F. C.
, and
Wang
T. S.
, “
Preparation and Microstructure Characteristics of Low-Temperature Bainite in Surface Layer of Low Carbon Gear Steel
,”
Applied Surface Science
257
, no.
17
(
2011
): 7609–7614,
4.
Wang
Y.
,
Yang
Z.
,
Zhang
F.
, and
Wu
D.
, “
Microstructures and Mechanical Properties of Surface and Center of Carburizing 23Cr2Ni2Si1Mo Steel Subjected to Low-Temperature Austempering
,”
Materials Science and Engineering: A
670
(
2016
): 166–177,
5.
Steinbacher
M.
and
Zoch
H.-W.
, “
CarboBain: Case Hardening by Carbo-Austempering: A Short Introduction to Transformation Kinetics, Microstructure and Residual Stresses
,”
HTM: Journal of Heat Treatment and Materials
72
, no.
5
(
2017
): 243–253.
6.
Braza
J.
,
Pearson
P.
, and
Hannigan
C.
, “
The Performance of 52100, M-50, and M-50 NiL Steels in Radial Bearings
” (SAE Technical Paper 932470, International Off-Highway and Powerplant Congress and Exposition,
1993
),
7.
Bhadeshia
H. K. D.
H.
, “
Steels for Bearings
,”
Progress in Materials Science
57
, no.
2
(
2012
): 268–435,
8.
Ooi
S.
and
Bhadeshia
H. K. D.
H.
, “
Duplex Hardening of Steels for Aeroengine Bearings
,”
ISIJ International
52
, no.
11
(
2012
): 1927–1934,
10.
Cylindrical Gears—ISO System of Flank Tolerance Classification
, ISO 1328:2013(E) (
Geneva, Switzerland
:
International Organization for Standardization
,
2013
).
11.
Hück
M.
,
“Ein Verbessertes Verfahren für die Auswertung von Treppenstufenversuchen” [An Improved Procedure for the Evaluation of Stair Step Tests]
,
Materials Science and Engineering Technology
14
, no.
12
(
1983
): 406–417.
12.
Calculation of Load Capacity of Spur and Helical Gears, Part 5: Strength and Quality of Materials
, ISO 6336-5:2016(E) (
Geneva, Switzerland
:
International Organization for Standardization
,
2016
).
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