The relation of hardness to toughness and retained austenite content in N2-H2-CH4 sintered T6, T15 and T42 high-speed steels

1990 ◽  
Vol 25 (7) ◽  
pp. 3359-3367 ◽  
Author(s):  
V. Martinez ◽  
R. Palma ◽  
J. J. Urcola
Keyword(s):  
Retained Austenite ◽  
High Speed ◽  
Austenite Content

scholarly journals Effect of Tempering Conditions on Secondary Hardening of Carbides and Retained Austenite in Spray-Formed M42 High-Speed Steel

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3714 ◽  
Author(s):  
Bowen Liu ◽  
Tian Qin ◽  
Wei Xu ◽  
Chengchang Jia ◽  
Qiuchi Wu ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Carbide Phase ◽  
Retained Austenite ◽  
High Speed ◽  
Bending Strength ◽  
High Speed Steel ◽  
Secondary Hardening ◽  
Electron Backscattered Diffraction ◽  
Scanning Calorimetry ◽  
Austenite Content

In this study, the effect of tempering conditions on microstructure, grain size, and carbide phase compositions of spray-formed high-speed steel after quenching at 1180 °C was studied. The influence of carbide phase, size of carbides, and retained austenite content on secondary hardening of the steel was analyzed by field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), electron backscattered diffraction (EBSD), and differential scanning calorimetry (DSC); the hardness, microhardness of carbide, and bending strength were tested. The results show that M3C, M6C, M7C3, and MC carbides may precipitate at different tempering temperatures and the transformation of the retained austenite can be controlled by tempering. The phase composition of carbides, microstructure, and retained austenite content strongly influences the performance characteristics of M42 high-speed steel after tempering. In contrast, the secondary carbides produced by tempering thrice at 540 °C are mainly M6C carbides rich in W and Mo elements, and the content of retained austenite is effectively reduced. At this stage, the Rockwell hardness reaches 67.2 HRC, bending strength reaches 3115 MPa, and the properties and microstructure are optimal.

Heat Treatment Effects on Distortion, Residual Stress, and Retained Austenite in Carburized 4320 Steel

2014 ◽  
Vol 783-786 ◽  
pp. 692-697 ◽  
Author(s):  
Andrew Clark ◽  
Randy J. Bowers ◽  
Derek O. Northwood
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Retained Austenite ◽  
Compressive Residual Stress ◽  
Surface Residual Stress ◽  
Depth Profiles ◽  
Size And Shape ◽  
Austenite Content ◽  
Treatment Conditions ◽  
The Difference

The effects of heat treatment on distortion, residual stress, and retained austenite were compared for case-carburized 4320 steel, in both the austempered and quench-and-tempered condition. Navy C-ring samples were used to quantify both size and shape distortions, as well as residual stress. The austempering heat treatment produced less distortion and a higher surface residual stress. Both hoop and axial stresses were measured; the difference between them was less than seven percent in all cases. Depth profiles were obtained for residual stress and retained austenite from representative C-ring samples for the austempered and quench-and-tempered heat treatment conditions. Austempering maintained a compressive residual stress to greater depths than quench-and-tempering. Quench-and-tempering also resulted in lower retained austenite amounts immediately beneath the surface. However, for both heat treatments, the retained austenite content was approximately one percent at depths greater than 0.5 mm.

Effects of Sequential Cuts on White Layer Formation and Retained Austenite Content in Hard Turning of AISI52100 Steel

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Xiao-Ming Zhang ◽  
Xin-Da Huang ◽  
Li Chen ◽  
Jürgen Leopold ◽  
Han Ding
Keyword(s):  
Layer Thickness ◽  
Process Parameters ◽  
Retained Austenite ◽  
Hard Turning ◽  
White Layer ◽  
Layer Formation ◽  
White Layer Thickness ◽  
Austenite Content ◽  
Sequential Cuts ◽  
White Layer Formation

This technical brief is the extension of our previous work developed by Zhang et al. (2016, “Effects of Process Parameters on White Layer Formation and Morphology in Hard Turning of AISI52100 Steel,” ASME J. Manuf. Sci. Eng., 138(7), p. 074502). We investigated the effects of sequential cuts on microstructure alteration in hard turning of AISI52100 steel. Samples undergone five sequential cuts are prepared with different radial feed rates and cutting speeds. Optical microscope and X-ray diffraction (XRD) are employed to analyze the microstructures of white layer and bulk materials after sequential cutting processes. Through the studies we first find out the increasing of white layer thickness in the sequential cuts. This trend in sequential cuts does work for different process parameters, belonging to the usually used ones in hard turning of AISI52100 steel. In addition, we find that the white layer thickness increases with the increasing of cutting speed, as recorded in the literature. To reveal the mechanism of white layer formation, XRD measurements of white layers generated in the sequential cuts are made. As a result retained austenite in white layers is identified, which states that the thermally driven phase transformations dominate the white layer formation, rather than the severe plastic deformation in cuts. Furthermore, retained austenite contents in sequential cuts with different process parameters are discussed. While using a smaller radial feed rate, the greater retained austenite content found in experiments is attributed to the generated compressive surface residual stresses, which possibly restricts the martensitic transformation.

Tool Steels

2015 ◽  
pp. 621-645
Keyword(s):  
Wear Resistance ◽  
Phase Transformations ◽  
Retained Austenite ◽  
High Speed ◽  
Cold Work ◽  
Heat Treating ◽  
Alloy Design ◽  
Tool Steels ◽  
Evolution Of Microstructure ◽  
Alloying Principles

Tools steels are defined by their wear resistance, hardness, and durability which, in large part, is achieve by the presence of carbide-forming alloys such as chromium, molybdenum, tungsten, and vanadium. This chapter describes the alloying principles employed in various tool steels, including high-speed, water-hardening, shock-resistant, and hot and cold work tool steels. It discusses the influence of alloy design on the evolution of microstructure and properties during solidification, heat treating, and hardening operations. It also describes critical phase transformations and the effects of partitioning, precipitation, segregation, and retained austenite.

scholarly journals Wear Resistance of High C High Si Steel with Low Retained Austenite Content and Kinetically Activated Bainite

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 672 ◽  
Author(s):  
Bojan Podgornik ◽  
Mihael Brunčko ◽  
Peter Kirbiš
Keyword(s):  
Wear Resistance ◽  
Retained Austenite ◽  
Adhesive Wear ◽  
Cold Work ◽  
High Hardness ◽  
Bearing Steel ◽  
Austenite Content ◽  
Surrounding Matrix ◽  
Aisi D2 ◽  
Wear Mode

A novel high C high Si carbide free bainitic steel was developed for the production of cold work tools, knives, and rolls, requiring high hardness, toughness, as well as abrasive/adhesive wear resistance and resistance to galling at low costs. The steel was tribologically tested in dry sliding conditions under abrasive and adhesive wear mode, facilitated by using alumina and bearing steel ball as a counter-material, respectively. It was determined that carbide dissolution occurs under high contact pressures, thereby enriching the surrounding matrix with carbon and locally increasing the retained austenite content. The high retained austenite at the sliding interface increases the steels work hardening capacity and promotes superior wear resistance when compared to much more alloyed cold work tool steel, such as AISI D2. The steel has a high resistance to galling as determined by sliding against a soft steel bar due to its chemical composition.

scholarly journals Study of the Origin of the Unexpected Pearlite during the Cooling Stage of Two Cast High-Speed Steels

2011 ◽  
Vol 172-174 ◽  
pp. 803-808 ◽  
Author(s):  
Jérôme Tchoufang Tchuindjang ◽  
Jacqueline Lecomte-Beckers
Keyword(s):  
Retained Austenite ◽  
High Speed ◽  
Solid Phase ◽  
Casting Process ◽  
Eutectic Phase ◽  
Chemical Compositions ◽  
Spin Casting ◽  
Eutectic Carbides ◽  
Similar Chemical ◽  
The Matrix

Two HSS grades (A and B) belonging to the complex system Fe-Cr-C-Si-X, where X is a strong carbide-forming element such as V, Mb or W, were studied. Samples in the as-received conditions came from an industrial spin casting process, with a varying cooling rate during processing. Chemical compositions of both alloys were closed to each other and were chosen to enhance their hardenability and to avoid less resistant phases such as pearlite and ferrite. Differential Thermal Analysis was performed on both alloys, in order to increase their crystallization behaviour. Light microscopy and SEM associated with EDS analyses were done to characterize the microstructure of both alloys in the as-received conditions and after DTA trials. The matrix of both HSS grades was composed of eutectic carbides, martensite and retained austenite, these phases exhibiting similar chemical compositions in both alloys. Unexpected pearlite was found in the as-cast HSS alloy B without W, this grade containing more Mo, more V and less Cr than the HSS grade A. It appeared from DTA tests that pearlite found in the alloy B arose more from the destabilisation of the Cr-rich retained austenite associated with the plate-like M2C carbide, than from the matrix itself. In fact, pearlite zones located in the vicinity of M2C are due to related isothermal solid phase transformations form the previous austenitic eutectic phase that is enriched with Cr and Mo.

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