scholarly journals Effect of the Parameters of Semi-Solid Processing on the Elimination of Sharp-Edged Primary Chromium Carbides from Tool Steel

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 713 ◽  
Author(s):  
Hana Jirková ◽  
Kateřina Rubešová ◽  
Pavel Konopík ◽  
Kateřina Opatová
Keyword(s):  
Solid State ◽  
Tool Steel ◽  
Tensile Tests ◽  
Hydraulic Press ◽  
Chromium Carbides ◽  
Routine Basis ◽  
Forming Temperature ◽  
Electron Microscopes ◽  
Semi Solid ◽  
Scanning Electron Microscopes

Although conventional tool steels have been heat treated on a routine basis for decades, the search continues for new ways to eliminate their troublesome sharp-edged primary chromium carbides, which impair toughness. One of the available techniques is semi-solid processing, which involves partial melting of the workpiece. The structure after semi-solid processing consisted of a austenite and carbide-austenite network. The network can be broken up and its fragments distributed uniformly by subsequent forming with appropriate parameters. In this experimental study, X210Cr12 tool steel was heated to a semi-solid state, and after cooling to a solid state, worked in a hydraulic press. Suitable soaking temperatures were sought within an interval between 1200 °C and 1280 °C. The workpieces were quenched from the forming temperature in water or oil. In order to improve formability and reduce hardness, tempering was tested as well. Additional experimental regimes included conventional quenching and tempering. Once the appropriate parameters were chosen, the elimination of primary chromium carbides was successful. The resultant microstructures were fine and consisted of M-A constituent with a size of approximately 1 μm, and very fine Fe3C and Cr7C3 carbides. The hardness was in excess of 800 HV10. They were examined using optical and scanning electron microscopes. The carbides were characterized on transparent foils in a transmission electron microscope. Mechanical characteristics were determined in micro-tensile tests.

Modelling Semi-Solid Behaviour and Brittle Temperature Range

2019 ◽  
Vol 285 ◽  
pp. 361-366 ◽  
Author(s):  
Khalil Traidi ◽  
Véronique Favier ◽  
Philippe Lestriez ◽  
Karl Debray ◽  
Laurent Langlois ◽  
...  
Keyword(s):  
Solid State ◽  
Material Properties ◽  
Solid Phase ◽  
Thermal Conditions ◽  
Tensile Tests ◽  
Internal Variable ◽  
Temperature Dependent ◽  
Brittle Transition ◽  
Semi Solid ◽  
First Time

In this paper, a new elastic viscoplastic micromechanical modelling is proposed to represent the semi-solid behaviour and predict the ductile-brittle transition of the C38LTT near the solidus. It is based on a viscoplastic modelling previously presented in [1]. The originality of the new model comes from three main enhancements: the transition between the solid state and the semi-solid state was included meaning that the material properties were taken temperature-dependent, the elastic properties was taken into account similarly as [2] and the evolution of the internal variable describing the degree of agglomeration of the solid phase was enhanced. The model was implemented in the commercial software FORGE©. Tensile tests representing the experimental thermal conditions and obtained using a GLEEBLE© machine were simulated. The comparison of the predicted and experimental results shows that, for the first time to our knowledge, the three steps of the load-displacement response and ductile-brittle transition were successfully described.

Forming of Biocompatible Materials in the Semi-Solid State

2008 ◽  
Vol 141-143 ◽  
pp. 55-60 ◽  
Author(s):  
Levente Kertész ◽  
Mathias Liewald
Keyword(s):  
Solid State ◽  
Life Time ◽  
High Melting ◽  
Machining Time ◽  
Wear Rates ◽  
Design Concepts ◽  
Forming Temperature ◽  
Temperature Levels ◽  
Semi Solid ◽  
Forming Tools

Semi-solid processing of materials provides advantages of both forging and casting. Experiments with high-melting and biocompatible alloys aiming at a “near-net-shape” production technology recently have been conducted. Advanced trials showed, that processing of such materials by means of semi-solid forming deliver a huge potential for feasible workpiece shapes and drastically reduces machining time and subsequent surface treatment efforts. In contrast to semi-solid forming of aluminium alloys at relatively low temperature levels any processing of high-melting point alloys in the semi-solid state is much more challenging due to higher forming temperature. Commonly used tool materials provoke high wear rates due to wetting, bonding and melting processes which finally result in a very short tool life time. Thus, more apt materials and composites for forming tools and dies which can withstand corrosion, wear, tear and extreme changes in temperatures have to be found. The development of new design concepts for long-living close-to-production tools based on such new materials will be a future goal.

High Spatial Resolution Low Energy Electron Beam X-ray Microanalysis

1999 ◽  
Vol 5 (S2) ◽  
pp. 310-311
Author(s):  
I.R. Barkshire ◽  
P. Karduck ◽  
W. Rehbach ◽  
S. Richter
Keyword(s):  
Energy Performance ◽  
Beam Current ◽  
Low Energy ◽  
Advanced Materials ◽  
X Ray ◽  
Routine Basis ◽  
Low Energy Electron ◽  
Electron Microscopes ◽  
Relative Errors ◽  
Scanning Electron Microscopes

Conventionally, x-ray microanalysis on scanning electron microscopes (SEM) with energy dispersive spectrometers (EDS) has been performed with relatively high primary energies (>10 kv). for most samples this results in reasonably good separation of the generated x-ray line series from different elements enabling unambiguous identification and therefore accurate qualitative analysis. Under these circumstances it is widely accepted that quantitative analysis of polished bulk samples is possible on a routine basis with relative errors around 1-5% and detection limits of the order of 0.1%.However, in order to address the analysis requirements of new advanced materials with sub-micron features, there is growing interest in performing x-ray microanalysis at low beam energies(<5kv). this is now a more realistic goal due to the routine availability of field emission sem's which can operate with much improved beam sizes at low beam energies with sufficient beam current to perform practical microanalysis, in conjunction with the improved low energy performance of current, commercially available EDS systems.

Finite-element simulation of semi-solid metal processing of tool steel encased in carbon steel

SIMULATION ◽  
2021 ◽  
pp. 003754972110610
Author(s):  
Eduardo Paixão Ritter ◽  
Felipe Tempel Stumpf
Keyword(s):  
Finite Element ◽  
Tool Steel ◽  
Tensile Tests ◽  
Solid Metal ◽  
Element Analysis ◽  
Precise Control ◽  
Element Simulation ◽  
Metal Processing ◽  
Scale Experiment ◽  
Semi Solid

The semi-solid metal processing allows for the production of components with complex geometries allied to lower forming forces. In the case of X210Cr12 tool steel, one big advantage of semi-solid metal processing is that it produces a microstructure free of precipitated chromium carbides, resulting in higher resistance to cyclic stresses. However, the application of this process in steels is limited until now due to technical difficulties, such as high temperatures, the necessity of a precise control of temperature, and the narrow liquidus–solidus range. For that reason, a preliminary numerical assessment of the forming procedure is highly welcome, in order to reduce potential errors in the final component. In this paper, we propose a methodology for the numerical simulation of semi-solid metal processing in steel samples under hot compression. We show that it is possible to use multilinear hardening plasticity models whose only input are the flow stress curves of each material. We also show that it is mandatory that these experimental curves are obtained through tensile tests performed at the same temperature as the working/simulated component. To validate the methodology, a full-scale experiment is undertaken so that the deformed sample can be compared to the numerical results. It is concluded that the methodology is suited for the assessment of mechanical quantities during the finite-element analysis of semi-solid processing of steel.

scholarly journals Tensile Deformation Behavior of Al-Cu 206 Cast Alloys near the Solidus Temperature

2016 ◽  
Vol 877 ◽  
pp. 90-96 ◽  
Author(s):  
Amir Bolouri ◽  
X. Grant Chen
Keyword(s):  
Tensile Deformation ◽  
Solidus Temperature ◽  
Tensile Tests ◽  
Different Temperatures ◽  
Cast Alloys ◽  
Electron Microscopes ◽  
Defect Nucleation ◽  
Semisolid Deformation ◽  
Set Up ◽  
Scanning Electron Microscopes

To study the micromechanics of semisolid deformation, a modified experimental set-up is employed in Gleeble 3800 thermomechamical testing unit to achieve a uniform temperature distribution in partially remelted aluminum samples. The temperature variation was markedly reduced to one degree for a length of 4-5 mm in the middle of tensile samples. High temperature semisolid tensile tests of Al-Cu 206 cast alloys were performed at different temperatures near solidus with a strain rate of 10-3 s-1, corresponding to the solid fractions (fs) between 1 and 0.95. The stress-displacement curves with different fs were measured and analyzed. The microstructure and fracture surface of samples were examined by optical and scanning electron microscopes. The relation between the microstructural characteristics, tensile properties and fracture behavior of semisolid 206 samples at high fs were explored. Mush deformation mechanisms were discussed in term of defect nucleation and propagation at the late stage of solidification.

High Temperature Tensile Properties of Equal Channel Angular Pressed Al-Zn-Mg-Cu Alloy

2012 ◽  
Vol 31 (6) ◽  
pp. 675-678 ◽  
Author(s):  
Süleyman Tekeli ◽  
Ahmet Güral
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Tensile Tests ◽  
Fine Grained ◽  
Angular Pressing ◽  
Cu Alloy ◽  
Elongation To Failure ◽  
Electron Microscopes ◽  
High Temperature Tensile ◽  
Scanning Electron Microscopes

AbstractIn this study, ultra fine-grained microstructure was produced in Al–Zn–Mg–Cu alloy by equal channel angular pressing (ECAP) at 200 °C and a pressing speed of 2 mm s−1 using route C. The microstructure of the specimens was characterized by transmission and scanning electron microscopes. The results showed that the mean grain size of the specimens effectively decreased with increasing pass number. That is, while the grain size of unECAPed specimen was 10 µm, this value decreased to 300 nm after 14 passes. High temperature tensile tests were carried out at a strain rate of 1 × 10− 2 and temperature of 250 °C in the specimens with different pass number. It was seen that the flow stress decreased and the elongation to failure significantly increased with increasing pass number. The highest elongation to failure value of 90% was obtained in the specimen after 14 passes.

scholarly journals Microstructural and Mechanical Properties of Selective Laser Melted Inconel 718 for Different Specimen Sizes

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Bartosz Madejski ◽  
Maciej Malicki ◽  
Sławomir Czarnewicz ◽  
Konrad Gruber
Keyword(s):  
Mechanical Properties ◽  
Inconel 718 ◽  
Tensile Tests ◽  
Microstructural Investigation ◽  
Microstructure And Mechanical Properties ◽  
Electron Microscopes ◽  
Mechanical And Microstructural Properties ◽  
Manufacturing Technologies ◽  
Scanning Electron Microscopes ◽  
Printing Direction

AbstractSelective laser melting (SLM) falls into the category of additive manufacturing technologies that are being increasingly used in the aerospace industry. This study presents the results of the examination of the microstructure and mechanical properties of selective laser melted Inconel 718. The tests were carried out for samples of different geometry (thickness, shape). The investigation showed the effect of the specimen’s size and the printing direction on the microstructure and mechanical properties. In the microstructural investigation, light and scanning electron microscopes were used. The microstructure investigation included measurements of the grain size and the carbides’ content. In order to estimate porosity computer tomography was used. Tensile tests were carried out at room temperature. The results showed differences in mechanical and microstructural properties of different size specimens.

Effects of Prilling Process on the Microstructures and Electrical Properties of Lanthanum Chromite Ceramics

2018 ◽  
Vol 281 ◽  
pp. 782-787
Author(s):  
Xing Lian Yin ◽  
Qing Zhao ◽  
Dong Lin He ◽  
Ai Min Chang
Keyword(s):  
Solid State ◽  
Electrical Properties ◽  
Solid State Reaction ◽  
Lanthanum Chromite ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

Lanthanum chromite(LaCrO3) with different amounts of PVB solution were synthesized by classical solid state reaction. We have studied the effects of different amounts of PVB solution( 0 mL, 1 mL, 2 mL, 3 mL) during prilling process on the microstructures and electrical properties of LaCrO3. The scanning electron microscopes, relative densities and resistivities of samples suggest: (1) the sinterability of LaCrO3is optimal among samples when adding 1 mL PVB solution to LaCrO3powder during prilling process. (2) sample with 1 mL PVB solution has the highest resistivity, while other counterparts’ resistivities have no distinct correspondence with the amount of PVB solution.

Semiconductor X-Ray Detection in the Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 130-131
Author(s):  
R. H. Duff ◽  
S. L. Bender
Keyword(s):  
Electron Microscope ◽  
Solid State ◽  
High Resolution ◽  
Gas Flow ◽  
X Ray ◽  
Solid State Detectors ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Conventional Transmission Electron Microscope

With the introduction of solid state detectors having resolutions of 300 eV or better, the feasibility of an efficient, nongeometry dependent X-ray detector of high resolution became a reality. The use of X-ray detecting systems in conjunction with electron microscopes has been limited to the dispersive type which is highly dependent on geometry or to the gas flow proportional counter which has poor resolution. Recently, high resolution solid state detectors have been used with scanning electron microscopes; however, no use has been made of them in the conventional transmission electron microscope. The usefulness of an elemental analysis together with morphological and crystallographic information is obvious.

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