Deformation Induced Pearlite Transformation and Spheroidization: Effect of Alloying Additions

2011 ◽  
Vol 409 ◽  
pp. 666-671 ◽  
Author(s):  
Matteo Caruso ◽  
Hector Verboomen ◽  
Stéphane Godet
Keyword(s):  
Microstructure Evolution ◽  
Hot Deformation ◽  
Eutectoid Steel ◽  
Torsion Testing ◽  
Alloying Additions ◽  
Steel Grades ◽  
Cr Addition ◽  
Hot Torsion ◽  
Kinetics Of ◽  
Undercooled Austenite

The aim of this research is to investigate the effect of Cr and Al (strong ferrite formers) on the strain-induced γ-to-pearlite transformation in eutectoid steels. The microstructure evolution during the hot deformation of three eutectoid steel grades was investigated using hot torsion testing. More specifically, the steels were deformed to strain levels varying from ε = 0,5 to ε = 1,5 at their specific Ar1 temperature. Hot deformation of the undercooled austenite leads to strain-induced γ-to-pearlite transformation and to the almost instantaneous spheroidization of the formed carbides. The corresponding microstructures consist of submicronic cementite particles and ferritic grains that are 1-5 μm in size. It is shown that 1,5% Cr addition and 0,5% Al addition increase the equilibrium transformation temperature but slower significantly the kinetics of the strain-induced transformation and consequently reduce the kinetics of cementite spheroidization and of ferrite recrystallization.

scholarly journals United Approach to Modelling of the Hot Deformation Behavior, Fracture, and Microstructure Evolution of Austenitic Stainless AISI 316Ti Steel

2021 ◽  
Vol 11 (7) ◽  
pp. 3204
Author(s):  
Alexander Yu. Churyumov ◽  
Svetlana V. Medvedeva ◽  
Olga I. Mamzurina ◽  
Alena A. Kazakova ◽  
Tatiana A. Churyumova
Keyword(s):  
Microstructure Evolution ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Stress Triaxiality ◽  
Grain Structure ◽  
Structure Evolution ◽  
Type Model ◽  
Hot Deformation Behavior ◽  
Tension Tests ◽  
Hot Torsion

Hot deformation is one of the main technological stages of products made from metallic materials. It is strictly required to decrease the costs of developing optimized technologies at this stage without a significant decrease in the products’ quality. The present investigation offers an algorithm to unite three different models to predict the hot deformation behavior, fracture, and microstructure evolution. The hot compression and tension tests of the AISI 316Ti steel were conducted using the thermomechanical simulator Gleeble 3800 for the models’ construction. The strain-compensated constitutive model and the Johnson–Mehl–Avrami–Kolmogorov (JMAK)-type model of the grain structure evolution show a satisfactory accuracy of 4.38% and 6.9%, respectively. The critical values of the modified Rice and Tracy fracture criteria were determined using the experimental values of the relative cross-section reduction and finite element calculation of the stress triaxiality. The developed models were approved for the stainless AISI 316Ti steel by the hot torsion with tension test.

Hot Torsion Tests - A Reliable Rolling Simulation Method for C-Mn Steels

2016 ◽  
Vol 879 ◽  
pp. 1783-1787 ◽  
Author(s):  
Fulvio Siciliano ◽  
Brian Allen ◽  
David Ferguson
Keyword(s):  
Flow Stress ◽  
Hot Deformation ◽  
Simulation Method ◽  
Absolute Temperature ◽  
Mean Flow ◽  
Torsion Testing ◽  
Torsion Mode ◽  
Mean Flow Stress ◽  
The Mean ◽  
Hot Torsion

Torsion tests have been proven to be a successful method to simulate the hot rolling of steels. Simulation work performed at a laboratory scale together with the analysis of the resulting mean-flow-stress behavior, leads to important metallurgical information to be considered during full-scale rolling processes. In this work, two different hot deformation schedules of C-Mn steels have been performed on a Gleeble simulation system in hot torsion mode. In addition to the torsion tests, the mean-flow-stresses of industrial rolling data were analyzed. Industrial hot deformation schedules simulated using hot torsion and the mean-flow-stress values were plotted versus the inverse of absolute temperature in the same graph. All points match the same behavior showing that torsion testing is a reliable hot working simulation method.

Constitutive Equations for Hot Extrusion of AA6005A, AA6063 and AA7020 Alloys

2011 ◽  
Vol 491 ◽  
pp. 43-50 ◽  
Author(s):  
Tommaso Pinter ◽  
Mohamad El Mehtedi
Keyword(s):  
Aluminum Alloys ◽  
Constitutive Equations ◽  
Hot Deformation ◽  
Fem Simulation ◽  
Hot Extrusion ◽  
Constitutive Relationship ◽  
Mechanical Parameters ◽  
Torsion Testing ◽  
Hot Torsion ◽  
Constitutive Parameters

Constitutive equations relate thermo-mechanical parameters, i.e. strain (ε), strain rate (έ) and temperature (T), with flow stress (σ). The most popular constitutive relationship, among those used in the study of hot deformation, is the phenomenological sinh Garofalo equation. In recent years several papers described the hot deformation of aluminum alloys by mean of hot torsion testing. However, sinh constitutive parameters are seldomly available in literature even for the commonest aluminum alloys used today by the extrusion industry. This paper presents the result of the torsion tests providing constitutive equations for AA6005A, AA6063 and AA7020 alloys. The relative extrudabilities of these alloys were estimated by means of FEM simulation carried out by the HyperXtrude® software.

Mechanical Properties of Plain Carbon Steels with Ultrafine (α+θ) Microstructures

2011 ◽  
Vol 682 ◽  
pp. 109-113
Author(s):  
Hai Yan Zhu ◽  
Long Fei Li ◽  
Wang Yue Yang ◽  
Zu Qing Sun
Keyword(s):  
Mechanical Properties ◽  
Carbon Steel ◽  
Hot Deformation ◽  
Tensile Tests ◽  
Total Elongation ◽  
Medium Carbon Steel ◽  
Carbon Steels ◽  
Eutectoid Steel ◽  
Medium Carbon ◽  
Undercooled Austenite

Mechanical properties of a medium-carbon steel with the ultrafine (α+θ) microstructures obtained by hot deformation of undercooled austenite and annealing were investigated by tensile tests, in comparison with that of a eutectoid steel. The results indicated that in the case of hot deformation of undercooled austenite to strain of 1.61 at 650°C at 0.01s-1 and annealing at 650°C for 30min, the ultrafine (α+θ) microstructures consisting of ultrafine ferrite grains and dispersed cementite particles were similar in the medium-carbon steel and the eutectoid steel, but the mechanical properties of the eutectoid steel were better that maybe be attributed to the relatively coarser size and the higher amount of cementite particles. With the increase of temperature for hot deformation of undercooled austenite to 700°C, the ultrafine (α+θ) microstructure of the medium-carbon steel changed obviously with the presence of some spheroidized pearlite colonies, and demonstrated the best balance of strength and elongation, the yield strength of about 545MPa, the tensile strength of about 635MPa, and the total elongation of about 35%.

scholarly journals Hot deformation behavior and related microstructure evolution in Au−Sn eutectic multilayers

2021 ◽  
Vol 31 (6) ◽  
pp. 1700-1716
Author(s):  
Yong MAO ◽  
Dan-li ZHU ◽  
Jun-jie HE ◽  
Chao DENG ◽  
Ying-jie SUN ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Hot Deformation Behavior

scholarly journals Influence of Deep Rolling and Induction Hardening on Microstructure Evolution of Crankshaft Sections made from 38MnSiVS5 and 42CrMo4

2021 ◽  
Vol 76 (3) ◽  
pp. 175-194
Author(s):  
A. Fischer ◽  
B. Scholtes ◽  
T. Niendorf
Keyword(s):  
Process Parameters ◽  
Microstructure Evolution ◽  
Surface Hardening ◽  
Qualitative Evaluation ◽  
Induction Hardening ◽  
Deep Rolling ◽  
Automotive Components ◽  
Hardening Treatment ◽  
Steel Grades ◽  
Definition Of

Abstract In order to improve properties of complex automotive components, such as crankshafts, in an application-oriented way, several surface hardening treatments can be applied. Concerning the material performance the definition of adequate process parameters influences the resulting surface properties and, thus, the effectiveness of surface hardening treatments. To analyze most relevant process-microstructure-property relationships, the present paper reports results obtained by two different well-established surface hardening procedures, i. e. deep rolling as a mechanical treatment and induction hardening as a thermal treatment. For each hardening process widely used crankshaft steel grades, i. e. a medium carbon 38MnSiVS5 microalloyed steel and a quenched and tempered 42CrMo4 were selected and thoroughly characterized upon processing, using equal parameter settings. The results reveal that deep rolling in contrast to induction hardening proves to be a less sensitive surface layer treatment with regard to small differences in the initial microstructure, the chemical composition and the applied process parameters. Differences in microstructure evolution with respect to the applied surface hardening treatment are studied and discussed for the highly stressed fillet region of automotive crankshaft sections for all conditions. In this context, high-resolution SEM-based techniques such as EBSD and ECCI are proven to be very effective for fast qualitative evaluation of induced microstructural changes.

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