scholarly journals Rolling-Element Fatigue Life of AMS 5749 Corrosion Resistant, High Temperature Bearing Steel

1978 ◽  
Vol 100 (2) ◽  
pp. 226-232 ◽  
Author(s):  
R. J. Parker ◽  
R. S. Hodder

The rolling-element fatigue lives of AMS 5749 and AISI M-50 were compared in tests run in the five-ball fatigue tester and the rolling-contact (RC) fatigue tester. The effects of double vacuum melting and retained austenite on the life of AMS 5749 were determined in five-ball fatigue tests. The double vacuum melting process consisted of induction vacuum melting followed by vacuum arc remelting (VIM-VAR). In the five-ball tests, VIM-VAR AMS 5749 gave lives at least six times that of VIM-VAR AISI M-50. Similar tests in the rolling-contact (RC) fatigue tester showed no significant difference in the lives of the two materials. The rolling-element fatigue life of VIM-VAR AMS 5749 was at least 14 times that of vacuum induction melted AMS 5749. A trend toward increased rolling-element fatigue life with decreased retained austenite is apparent, but the confidence that the all experimental differences are significant is not great. The highest level of retained austenite, 14.6 percent, is, however, significantly detrimental to rolling-element fatigue life, relative to the intermediate level of 11.1 percent.

2012 ◽  
Vol 706-709 ◽  
pp. 2152-2157 ◽  
Author(s):  
Kwan Ho Kim ◽  
Jae Seung Lee ◽  
Duk Lak Lee

Over the decades, the rolling contact fatigue life of bearing steels has been enhanced mainly by the decrease in total oxygen content in the steels which was accomplished by improving steelmaking processes or facilities. However, it has almost been kept constant in the level of 5 ppm since 1990s and, therefore, it is necessary to find out other methods to enhance the RCFL. It is a well-known fact that the RCFL of bearing steels is maximized with the adequate amount of retained austenite and increasing silicon content results in the increase of the resistance to softening during tempering. In the present study, in order to take advantage of the effects of retained austenite and increasing silicon content, a new through-hardening heat treatment, quenching and partitioning (Q&P), has been chosen in place of the conventional quenching and tempering. One of the distinct differences between tempering and partitioning is no fine carbide precipitation during partitioning, leading to the stabilization of retained austenite due to the diffusion of carbon atoms from martensite, which can be realized by increasing silicon content. On the other hand, the increase of silicon content retarded the spheroidization behavior of cementites, requiring higher annealing temperature to assure the complete spheroidization. A new high carbon chromium bearing steel through-hardened by Q&P process showed superior RCFL characteristics to the conventional steel and process.


1982 ◽  
Vol 104 (3) ◽  
pp. 330-334 ◽  
Author(s):  
A. H. Nahm

Accelerated rolling contact fatigue tests were conducted to study the effect of grain flow orientation on the rolling contact fatigue life of vacuum induction melted and vacuum arc remelted (VIM-VAR) AISI M-50. Cylindrical test bars were prepared from a billet with 0, 45, and 90 deg orientations relative to billet forging flow direction. Tests were run at a Hertzian stress of 4,826 MPa with a rolling speed of 12,500 rpm at room temperature, and lubricated with Type I (MIL-L-7808G) oil. It was observed that rolling contact fatigue life increased when grain flow line direction became more parallel to the rolling contact surface.


Author(s):  
Delia F. Cerlinca ◽  
Emanuel N. Diaconescu

Rolling contact fatigue depends essentially on both surface and subsurface populations of defects. First, this paper describes experimental results obtained in rolling contact fatigue tests in the presence of a furrow oriented transversally to the race-way. Then an attempt to predict theoretically the effect of geometric parameters of the furrow upon contact fatigue life is described.


1967 ◽  
Vol 89 (1) ◽  
pp. 63-72 ◽  
Author(s):  
E. N. Bamberger

A development program has been conducted on M-50 to determine the improvements possible in bearing steels by the incorporation of a hot-cold working (ausforming) treatment in their processing. Primary emphasis was on the improvements possible in rolling contact fatigue. In support of this, heat-treat, corrosion, hardness, and microstructural studies have been performed. It has been shown that a certain process for working steel in the metastable austenitic condition as applied to the rolling contact fatigue life of M-50 bearing steel will substantially improve life, thereby increasing bearing reliability. The remarkable improvements in life (exceeding 800 percent) will be a significant factor in meeting the long-life-bearing requirements for advanced air-breathing propulsion systems. A metallurgical analysis has been conducted and a mechanism is proposed which is thought to be the primary factor in providing the significant improvements in rolling contact fatigue life. It is shown that these improvements in life are possible without any significant increase in hardness of the subject materials. Evidence is presented which indicates that the life improvement is primarily due to more uniform carbide dispersion, reduction of massive carbide particles, and reduction in martensite platelet size. These microstructural changes are believed to be associated with strain-induced precipitation and its interplay with strain-hardening during the deformation cycle.


2012 ◽  
Vol 457-458 ◽  
pp. 504-510
Author(s):  
Masatoshi Koga ◽  
Edson Costa Santos ◽  
Takashi Honda ◽  
Katsuyuki Kida ◽  
Takuya Shibukawa

Due to its high hardness and wear resistance under rolling contact, AISI E52100 steel (JIS SUJ2) is used in the manufacture of bearings and linear guides. The life estimation methods for components working under rolling contact developed up to now were designed for bearings. In this study, fatigue testing under reciprocating motion was performed and based on the microstructure, wear track investigation as well as hardness and retained austenite measurements, an evaluation method for linear guides is proposed. The results obtained from three different areas of the sample including wear tracks and non-damaged area are as follows: (1) there was little microstructure difference between the center and the end of the wear track; (2) a clear difference of the retained austenite content at the wear track and at the non-damaged area could be observed, however the percentage within different areas inside the track was similar.


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