Effect of pre-quenching on martensite-bainitic microstructure and mechanical properties of GCr15 bearing steel

Li, C.; Wang, J. L.

doi:10.1007/bf00367570

Cited by 25 publications

(13 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The given tempering temperature represents a decisive or crucial factor in the extent of structural changes and changes related to the mechanical properties of stainless steels. The values of notch and fracture toughness are decreased in the steel with the occurrence of tempering embrittlement and, moreover, there is a higher susceptibility to corrosion cracking or hydrogen embrittlement [ 14 , 15 , 16 ]. Nickel chromium and manganese chromium steels in particular tend to be brittle because of the toughness decrease even during the slow cooling from the tempering temperature in comparison with manganese, nickel and chromium steels, which tend to be brittle only when they are held at a given temperature for a long time.…”

Section: Introductionmentioning

confidence: 99%

Fracture Analysis of High-Strength Screw for Highway Construction

Dubec

Kováčiková²,

Krmela³

et al. 2021

Materials

View full text Add to dashboard Cite

High-strength screws represent one of the main joining or fastening components which are commonly used in the process of installation of frame constructions for information boards or signposts, relating to the traffic roads. The control of the production process may not always be a sufficient method for ensuring road safety. The backward investigation and control of the screw material processing seems to be the one of the most important procedures when there is the occurrence of any failure during the operation of the screw. This paper is mainly focused on the analysis of the failure of the high-strength screw of 10.9 grade with M diameter of 27 × 3 and a shank length of 64 mm. The mentioned and investigated screw was used as a fastener in a highway frame construction. In the paper, there is mainly the analysis of the material for a broken screw in terms of the material micropurity, the material microstructure, the surface treatment as well as chemical composition. The evaluation was based on investigation by optical microscopy, scanning electron microscopy and energy dispersive spectroscopy. Important knowledge and results were also obtained due to information on micromorphology and material contrast of the fracture surface resulting from fractographic analysis, using the method of scanning electron microscopy. In the case of the production of the high-strength screws, the tempering stands for the decisive or crucial process of heat treatment because the given process can ensure a decrease in hardness, while the required ductile properties of the material are kept and this is also reflected in the increase of strength and micromorphology of the fracture surface. From the aspect of micropurity, inclusions of critical size or distribution were not identified in the material, referring to Czech standard ČSN ISO 4967 (420471). The microstructure corresponds to tempered martensite, but the fracture surface of the broken screw was based on an intercrystalline micromechanism, which is undesirable for the given type of component. Combined with the measurement of the HV1 (Vickers hardness at a load of 1 kg) from the edge to the central area of the screw, the analysis revealed the significant drawbacks in the heat treatment of the high-strength screw.

show abstract

Section: Introductionmentioning

confidence: 99%

Fracture Analysis of High-Strength Screw for Highway Construction

Dubec

Kováčiková²,

Krmela³

et al. 2021

Materials

View full text Add to dashboard Cite

show abstract

“…Wei et al [13] believed that the M/B duplex microstructure obtained by austempering could improve the impact toughness of bearing steel compared with traditional martensite quenching-tempering (Q-T) heat treatment. Li et al [14] reported that an excellent combination of strength and toughness could be obtained by combining pre-quenching with austempering. Moreover, the acquisition of partial lower bainite in bearing steels can improve the toughness of the material, and thus contribute to the rolling contact fatigue life of bearings [15].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of M50 Steel by Combining Cold Rolling with Austempering

Qian

Wang

et al. 2020

Metals

View full text Add to dashboard Cite

The microstructure and mechanical properties of M50 steel subjected to combining cold rolling (CR) with austempering are investigated. The microstructure is characterized using X-ray diffraction and scanning and transmission electron microscopy. The mechanical properties are measured using the uniaxial tensile and Charpy impact tests. It is observed that an excellent combination of ultimate tensile strength (2536 MPa) and impact toughness (128 J) was achieved by combining austempering with CR; of which the ultimate tensile strength increased by 10% compared with traditional martensite quenching-tempering (Q-T) specimen and the impact absorbed energy exhibited 2.3 times of that in Q-T specimen. The observation of the microstructure indicates that CR obviously refines the thickness of bainite sheaves, which is favorable for the formation of ultrafine equiaxed ferrite during tempering.

show abstract

“…In recent years, many studies on the mechanical properties of multiphase steel have been reported in the literature [15,16,17]. Many investigations have indicated that whether low or high, carbon content generally increases the strength of steel by yielding a quenched martensite phase [18]. Zare et al [12] investigated the effects of the martensite volume fraction on the tensile properties of a ferrite–pearlite–martensite triple-phase microstructure and reported that the strength increased with an increase in the martensite volume fraction.…”

Section: Introductionmentioning

confidence: 99%

Microstructure Transformation on Pre-Quenched and Ultrafast-Tempered High-Strength Multiphase Steels

et al. 2019

View full text Add to dashboard Cite

High-strength, multiphase steels consisting of pearlite surrounded by tempered martensite were prepared by pre-quenching and ultrafast tempering heat treatment of high-carbon pearlitic steels (0.81% C). The microstructures were analyzed by scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy. With an increasing quenching temperature from 120 °C to 190 °C, the quenched martensite variants nucleated via autocatalytic nucleation along the interface. Furthermore, the tempered nodules exhibited a distinct symmetrical structure, and the tempered martensite and pearlitic colonies in the group also showed a symmetrical morphology. In addition, a reasonable model was formulated to explain the transformation process from quenching martensite to the multiphase microstructure. When the quenching temperature was set to 120 °C, followed by ultrafast heating at 200 °C/s to 600 °C and subsequent isothermal treatment for 60 s, the multiphase structure showed highest strength, and the pearlite volume fraction after tempering was the lowest. The microhardness softening mechanism for the tempered structures consisted of two stages. The first stage is related to martensitic sheets undergoing reverse transformation and the nucleation of cementite on dislocations. The second stage involves the transformation of austenite into pearlite and continued carbide coarsening in the martensitic matrix.

show abstract

Effect of pre-quenching on martensite-bainitic microstructure and mechanical properties of GCr15 bearing steel

Cited by 25 publications

References 3 publications

Fracture Analysis of High-Strength Screw for Highway Construction

Fracture Analysis of High-Strength Screw for Highway Construction

Microstructure and Mechanical Properties of M50 Steel by Combining Cold Rolling with Austempering

Microstructure Transformation on Pre-Quenched and Ultrafast-Tempered High-Strength Multiphase Steels

Contact Info

Product

Resources

About