Globular Microstructure Formation in X210CrW12 Steel for Semi Solid Processing Using Plastic Deformation or Boron Modification

2013 ◽  
Vol 58 (3) ◽  
pp. 751-755 ◽  
Author(s):  
Ł. Rogal ◽  
J. Dutkiewicz
Keyword(s):  
Plastic Deformation ◽  
Liquid Fraction ◽  
Eutectic Mixture ◽  
Microstructure Formation ◽  
Hot Plastic Deformation ◽  
Globular Microstructure ◽  
Boron Modification ◽  
Average Grain Size ◽  
Advance Method ◽  
Semi Solid

Abstract Semi-solid processing (SSP) belongs to advance method of forming metal alloys in the solidus-liquidus range. Such technology requires a fine globular microstructure in a semi-solid range, which can be produced by numerous methods. The present paper focuses on two methods of preparation of a globular microstructure in X210CrW12 tool steel as a possible way of preparation of feedstock for thixoforming: hot plastic deformation (SIMA), and modification with boron. DSC analysis allowed to establish the amount of liquid phase fraction vs temperature. Samples were heated up to the semi-solid temperature range - 1230°C, which corresponds to 17% (SIMA) and 30% (modified) of the liquid fraction. Then they were rapidly cooled. The obtained microstructures of samples were investigated for their suitability for SSP. The microstructure of X210CrW12 steel prepared by SIMA shows a globular microstructure with average grain size 57 μm. The samples after modification with 0.08% (weight pct) boron also feature a globular microstructure with the size of 46 μm. The grains possess an austenitic structure and are surrounded by an eutectic mixture

Microstructure Evolution and Coarsening Mechanism of 7075 Semi-Solid Aluminum Alloy Pre-Deformed by ECAP Method

2016 ◽  
Vol 256 ◽  
pp. 294-300 ◽  
Author(s):  
Jin Long Fu ◽  
Yu Wei Wang ◽  
Kai Kun Wang ◽  
Xiao Wei Li
Keyword(s):  
Aluminum Alloy ◽  
Solid State ◽  
Ostwald Ripening ◽  
Liquid Fraction ◽  
Isothermal Holding ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Semi Solid ◽  
Equiaxed Grains ◽  
Kinetics Of

To investigate the influence of refined grains on the microstructure of 7075 aluminum alloy in semi-solid state, a new strain induced melting activation (SIMA) method was put forward containing two main stages: pre-deformation with equal channel angular pressing (ECAP) method and isothermally holding in the semi-solid temperature range. The breaking up and growth mechanisms of the grains and kinetics of equiaxed grains coarsening during the semi-solid holding were investigated. The results showed that the average grain size after ECAP extrusion decreased significantly, e.g., microstructure with average globular diameter less than 5μm was achieved after four-pass ECAP extrusion. Obvious grain coarsening had been found during isothermal holding in the semi-solid state and the roundness of the grains increased with the increasing holding time. The proper microstructure of 66.8μm in diameter and 1.22 in shape factor was obtained under proper soaking condition (at 590°C for 15 min). Two coarsening mechanisms, namely, coalescence in lower liquid fraction and Ostwald ripening in higher liquid fraction contributed to the grain growth process.

Evolution of Globular Microstructures during Direct Partial Re-Melting Experiment of AISI D2 Tool Steel

2013 ◽  
Vol 465-466 ◽  
pp. 829-833 ◽  
Author(s):  
M.N. Mohammed ◽  
Mohd Zaidi Omar ◽  
Junaidi Syarif ◽  
Zainuddin Sajuri ◽  
Mohd Shukor Salleh ◽  
...  
Keyword(s):  
Tool Steel ◽  
Liquid Fraction ◽  
Cold Work ◽  
Surface Oxidation ◽  
Eutectic Carbides ◽  
Average Grain Size ◽  
Aisi D2 ◽  
Semi Solid ◽  
Semisolid Process ◽  
Cold Work Tool Steel

Steel is a mostly challenging metal to semisolid process because of the high temperatures implicated and the prospective for surface oxidation. Slurry processing experiment was performed with AISI D2 cold work tool steel to identify the evolution of globular microstructures via Direct Partial Re-Melting Method (DPRM). Samples were heated in an argon atmosphere up to 1330°C which corresponded to about 38% of liquid fraction and held for 5 minutes. The typical microstructure after DPRM consists of globular grains (average grain size about 50μm) while the remaining interspaces were filled by precipitated eutectic carbides on the grain boundaries and lamellar network. Based on the requirements of thixoformability, the current work confirms the suitability of the AISI D2 cold work tool steel as a candidate material for semi-solid forming.

On the Microstructure of XW-42 Steel after Direct Partial Remelting

2010 ◽  
Vol 154-155 ◽  
pp. 1280-1283 ◽  
Author(s):  
Afzalur Alfan ◽  
Mohd Zaidi Omar ◽  
Junaidi Syarif
Keyword(s):  
Partial Melting ◽  
Liquid Fraction ◽  
Processing Temperature ◽  
Forming Process ◽  
Annealed Condition ◽  
Partial Remelting ◽  
Average Grain Size ◽  
Pre Treatment ◽  
Semi Solid ◽  
Melting Experiment

In order to be considered as a material for semi-solid processing, an alloy has to possess solid spheroids within liquid matrix. Therefore, it is important to investigate the structure of the candidate alloy prior to forming process by conducting partial melting experiment. In this research, the partial melting was conducted for XW-42 steel directly from as annealed condition without any pre-treatment (Direct Partial Remelting). Liquid Fraction Profile obtained from Differential Thermal Analysis (DTA) showed that temperature of 1340°C was located in a low temperature sensitivity region, hence making it as a candidate for processing temperature. Direct Partial Remelting at this temperature for 0, 2 and 5 minutes revealed near spheroidal structure with average grain size between between 45-51 µm which can be considered suitable for semi-solid processing.

Preparation of Globular Microstructure in H18 Steel for Semi Solid Processing with the Use of Boron Addition

2014 ◽  
Vol 217-218 ◽  
pp. 8-14 ◽  
Author(s):  
Jan Dutkiewicz ◽  
Jan Głownia ◽  
Łukasz Rogal
Keyword(s):  
Eutectic Mixture ◽  
Surface Oxidation ◽  
Rapid Quenching ◽  
Composition Analysis ◽  
Cast Sample ◽  
X Ray ◽  
Average Grain Size ◽  
Initial Hardness ◽  
Semi Solid ◽  
Temperature Surface

Martensitic stainless steel was chosen for a semi-solid processing due to high mechanical properties and resistance to high temperature surface oxidation. Modified H18 martensitic steel (1.1 % - C, 18.9 % - Cr, 0.1 % - V, 0.7 % - Mo, 0,9 % - Si, 2.0 % - Mn, balance Fe, all in weight %) modified with addition of 0.01 % boron was applied as a feedstock for semi-solid range temperature experiments. The samples were heated up to 1330°C to obtain about 26% of the liquid phase followed by rapid quenching in water. The microstructure of the samples consisted of austenitic globular grains (average grain size 42 μm, about 78 % of volume) surrounded by a eutectic mixture (ferrite, and M7C3,M23C6carbides as identified by X-ray and electron diffraction). The initial hardness of as-cast sample was 357 HV5and that after quenching from liquidus solidus range was 422 HV5. The X-ray analysis confirmed the presence of 16% - α-Fe, 80% - γ-Fe and 4% - M7C3carbides in rapid quenched sample. The EDS analysis of a eutectic mixture was as follows: 6.2 % - C, 31.7 % Cr, 0.1 % - Mn, 0.6 % - Si, 61.2 % Fe. The chemical composition analysis of globular grains confirmed the presence of 2.0% C, 16.3 % - Cr, 1 % - Si, 1.7 % - Mn, 0.5 % - Mo, 78.5% Fe.

scholarly journals Structural Transformations and Mechanical Properties of Metastable Austenitic Steel under High Temperature Thermomechanical Treatment

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 645
Author(s):  
Igor Litovchenko ◽  
Sergey Akkuzin ◽  
Nadezhda Polekhina ◽  
Kseniya Almaeva ◽  
Evgeny Moskvichev
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Temperature ◽  
Austenitic Steel ◽  
Structural Transformations ◽  
Initial State ◽  
Twin Boundaries ◽  
Metastable Austenitic Steel ◽  
Average Grain Size ◽  
Heating Up

The effect of high-temperature thermomechanical treatment on the structural transformations and mechanical properties of metastable austenitic steel of the AISI 321 type is investigated. The features of the grain and defect microstructure of steel were studied by scanning electron microscopy with electron back-scatter diffraction (SEM EBSD) and transmission electron microscopy (TEM). It is shown that in the initial state after solution treatment the average grain size is 18 μm. A high (≈50%) fraction of twin boundaries (annealing twins) was found. In the course of hot (with heating up to 1100 °C) plastic deformation by rolling to moderate strain (e = 1.6, where e is true strain) the grain structure undergoes fragmentation, which gives rise to grain refining (the average grain size is 8 μm). Partial recovery and recrystallization also occur. The fraction of low-angle misorientation boundaries increases up to ≈46%, and that of twin boundaries decreases to ≈25%, compared to the initial state. The yield strength after this treatment reaches up to 477 MPa with elongation-to-failure of 26%. The combination of plastic deformation with heating up to 1100 °C (e = 0.8) and subsequent deformation with heating up to 600 °C (e = 0.7) reduces the average grain size to 1.4 μm and forms submicrocrystalline fragments. The fraction of low-angle misorientation boundaries is ≈60%, and that of twin boundaries is ≈3%. The structural states formed after this treatment provide an increase in the strength properties of steel (yield strength reaches up to 677 MPa) with ductility values of 12%. The mechanisms of plastic deformation and strengthening of metastable austenitic steel under the above high-temperature thermomechanical treatments are discussed.

scholarly journals Influence of Hydrostatic Extrusion on the Mechanical Properties of the Model Al-Mg Alloys

2021 ◽  
Author(s):  
Aleksandra Towarek ◽  
Wojciech Jurczak ◽  
Joanna Zdunek ◽  
Mariusz Kulczyk ◽  
Jarosław Mizera
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Tensile Strength ◽  
Microstructural Analysis ◽  
Tensile Tests ◽  
Hydrostatic Extrusion ◽  
Microstructure Formation ◽  
Initial State ◽  
Degree Of Deformation ◽  
Al Mg Alloys

AbstractTwo model aluminium-magnesium alloys, containing 3 and 7.5 wt.% of Mg, were subjected to plastic deformation by means of hydrostatic extrusion (HE). Two degrees of deformation were imposed by two subsequent reductions of the diameter. Microstructural analysis and tensile tests of the materials in the initial state and after deformation were performed. For both materials, HE extrusion resulted in the deformation of the microstructure—formation of the un-equilibrium grain boundaries and partition of the grains. What is more, HE resulted in a significant increase of tensile strength and decrease of the elongation, mostly after the first degree of deformation.

GRAIN REFINEMENT AND MICROSTRUCTURE EVOLUTION IN ALUMINUM A2618 ALLOY BY HIGH-PRESSURE TORSION

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Intan Fadhlina Mohamed ◽  
Seungwon Lee ◽  
Kaveh Edalati ◽  
Zenji Horita ◽  
Shahrum Abdullah ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Grain Refinement ◽  
Room Temperature ◽  
Rotation Speed ◽  
High Pressure Torsion ◽  
Applied Pressure ◽  
Saturation Level ◽  
Microstructural Refinement ◽  
Average Grain Size

This work presents a study related to the grain refinement of an aluminum A2618 alloy achieved by High-Pressure Torsion (HPT) known as a process of Severe Plastic Deformation (SPD). The HPT is conducted on disks of the alloy under an applied pressure of 6 GPa for 1 and 5 turns with a rotation speed of 1 rpm at room temperature. The HPT processing leads to microstructural refinement with an average grain size of ~250 nm at a saturation level after 5 turns. Gradual increases in hardness are observed from the beginning of straining up to a saturation level. This study thus suggests that hardening due to grain refinement is attained by the HPT processing of the A2618 alloy at room temperature.

Microstructure and Mechanical Properties of Mg-6Zn-1.4Y Alloy Produced by Rheo-Squeeze Casting Process

2016 ◽  
Vol 879 ◽  
pp. 530-535
Author(s):  
Xiao Gang Fang ◽  
Shu Sen Wu ◽  
Shu Lin Lü
Keyword(s):  
Mechanical Properties ◽  
Power Density ◽  
Squeeze Casting ◽  
Casting Process ◽  
Acoustic Power ◽  
Icosahedral Quasicrystal ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size ◽  
Grain Size And Shape ◽  
Semi Solid

Mg-Zn-Y alloys containing a thermally stable icosahedral quasicrystal phase (I-phase) will have wide application future on condition that primary α-Mg dendrite and the I-phase can be refined during the casting process. In this research, the microstructure and mechanical properties of the rheo-squeeze casting (RSC) Mg-6Zn-1.4Y alloys have been investigated. The Mg alloy melt was exposed to ultrasonic vibration (USV) with different acoustic power densities from 0 W/mL to 9 W/mL, and then the slurry was formed by squeeze casting. The results show that good semi-solid slurry with fine and spherical α-Mg particles could be obtained with the acoustic power density of 6 W/mL, and the average grain size and shape factor of primary α-Mg were 32 μm and 0.76, respectively. Meanwhile the coarse eutectic I-phase (Mg3Zn6Y) was refined obviously and dispersed uniformly. Compared with the samples without USV, the tensile strength and elongation of the RSC casting samples with 6 W/mL acoustic power density were elevated by 10.6% and 55.5%, respectively.

Fracture of ledeburite steel during hot plastic deformation

1977 ◽  
Vol 19 (5) ◽  
pp. 398-400
Author(s):  
V. P. Nikitin ◽  
Yu. A. Borisov ◽  
S. I. Bulat ◽  
V. V. Zaitsev
Keyword(s):  
Plastic Deformation ◽  
Hot Plastic Deformation
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