scholarly journals Investigation of the microstructure evolution of 7CrMn2WMo economy‑alloyed steel in a new design forging tool implementing shear deformations

2021 ◽  
pp. 106-111
Author(s):  
S. N. Lezhnev ◽  
A. B. Naizabekov ◽  
I. E. Volokitina ◽  
E. A. Panin ◽  
D. V. Kuis ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Microstructure Evolution ◽  
Design Tool ◽  
Alloyed Steel ◽  
Shear Deformations ◽  
Cast Structure ◽  
Intense Shear

In this paper, a new forging technology realizing intense shear deformations during processing with a tool for its implementation was considered, and the influence of the proposed forging technology on the microstructure evolution of 7CrMn2WMo economy‑alloyed steel was revealed. A comparative analysis of the results of the microstructure evolution when forging blanks made of 7CrMn2WMo steel according to the proposed and current technologies proves the usefulness of a new design tool instead of the currently used flat strikers, since forging in the proposed forging tool provides more intensive and uniform processing of the cast structure over the entire section of the workpiece compared to forging in the flat strikers.

Microstructure and Properties of T2 Copper Tube Produced by Severe Hot Rolling

2010 ◽  
Vol 667-669 ◽  
pp. 193-198 ◽  
Author(s):  
Ya Li Wang ◽  
Ying Liu ◽  
Jing Tao Wang ◽  
Fu Sheng Tian
Keyword(s):  
Mechanical Properties ◽  
Microstructure Evolution ◽  
Hot Rolling ◽  
Optical Microscope ◽  
Copper Tube ◽  
Cast Structure ◽  
Microstructure And Properties ◽  
Microstructure Transformation ◽  
Equiaxed Grains ◽  
Rolling Deformation

In this study, the microstructure evolution as well as mechanical properties of T2 copper tube during severe hot rolling has been investigated. Owing to the severe hot rolling deformation and high rolling temperature, the microstructure of T2 copper tube evolved from initial cast structure into relatively homogenous and equiaxed grains during the process, which was testified through the results of optical microscope observation. Besides, the microhardness measurements were taken, from which the results gained were in correspondence to the microstructure transformation.

Anisotropy in Cold Rolling of Single Crystalline Ni3-Al-Base Intermetallic Alloys

2005 ◽  
Vol 495-497 ◽  
pp. 737-742 ◽  
Author(s):  
Kyosuke Kishida ◽  
Masahiko Demura ◽  
Toshiyuki Hirano
Keyword(s):  
Cold Rolling ◽  
Single Crystals ◽  
Microstructure Evolution ◽  
Rolling Direction ◽  
Stacking Faults ◽  
Intermetallic Alloys ◽  
Shear Deformations ◽  
Planar Defects ◽  
Crystal Orientations ◽  
Initial Crystal

Texture and microstructure evolution during cold rolling of binary Ni3Al single crystals were studied as a function of the initial crystal orientations. Cold rolling behavior of the single crystals is strongly dependent on the initial crystal orientations, especially on the initial rolling direction (RD). Macroscopic texture evolutions for binary Ni3Al single crystals with the initial RD close to <001> are characterized as development of dual {110}<¯112> texture above 90% cold reduction and the banded structure formation. Microstructure observations reveal the extensive formation and accumulation of the planar defects including the stacking faults and the planes where the localized shear deformations occurs, which must be responsible for the observed anisotropic cold rolling behavior of Ni3Al single crystals.

Microstructure Evolution During Hot Deformation of a Micro-Alloyed Steel

2016 ◽  
Vol 70 (4) ◽  
pp. 1019-1033 ◽  
Author(s):  
G. K. Mandal ◽  
V. Rajinikanth ◽  
Sunil Kumar ◽  
Dipesh Mishra ◽  
S. Misra ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Hot Deformation ◽  
Alloyed Steel ◽  
Micro Alloyed Steel

Numerical prediction on microstructure evolution for multi-stage hot forging of micro-alloyed piston

2014 ◽  
Vol 31 (5) ◽  
pp. 923-938 ◽  
Author(s):  
Jun Chen ◽  
Jin Wang
Keyword(s):  
Flow Stress ◽  
Microstructure Evolution ◽  
Hot Forging ◽  
Alloyed Steel ◽  
Stress Model ◽  
Content Type ◽  
Forging Process ◽  
Multi Stage ◽  
Micro Alloyed Steel ◽  
Flow Stress Model

Purpose – The purpose of this paper is to build a flow stress model and microstructure evolution models which can be used to fulfill the multi-physics prediction of hot forging process, in this way the process design can be virtually verified and optimized. This is especially crucial for micro-alloyed steel forging which microstructure determines the component properties, since the downstream quenching is usually not needed. Design/methodology/approach – First, hot compression tests have been completed; second, experimental data are used to build the flow stress model and models for microstructure evolution; third, programming has been finished to integrate the proposed models into the commercial finite element method (FEM) code; fourth, case study is conducted to simulate multi-stage hot forging process of micro-alloyed steel F38MnV piston; and fifth, simulation results are validated by experiment. Findings – First, simulation results in grain size and phase volume fraction are in well agreement with experimental ones; second, the austenite grain is dramatically refined by the dynamic recrystallization in pre-forging process and static recrystallization in the two intervals has no obvious change during the following final forging and cooling above the Ae3 temperature; third, during the cooling process below the Ae3 temperature, ferrite and pearlite transformation begin from the thin skirt to the thick skirt and piston bottom because of different cooling speeds at different areas. Originality/value – First, flow stress model, dynamic recrystallization model, static recrystallization model, austenite grain growth model and phase transformation models are established for a micro-alloyed steel; second, the multi-physics FEM simulation of multi-stage hot forging of industrial piston has been conducted and verified by experiment, which show good agreement.

Microstructure Refinement and Crack Initiation in the Forging Process

2014 ◽  
Vol 936 ◽  
pp. 1641-1646
Author(s):  
Wen Long Zhao ◽  
Qing Xian Ma
Keyword(s):  
Shear Stress ◽  
Crack Initiation ◽  
Grain Boundaries ◽  
Microstructure Evolution ◽  
Reduction Ratio ◽  
Metallographic Analysis ◽  
Forging Process ◽  
Coarse Grains ◽  
Intense Shear ◽  
Optimal Reduction

In this paper, the type and morphology of defects in heavy ingots were detected mainly on the basis of experimental results, which were obtained by metallographic analysis of the materials dissected from one 380 ton 30Cr2Ni4MoV ingot. Then the evolution of typical defects in the forging process was investigated at temperatures ranging from 900°C to 1200°C and reduction ratios ranging from 0% to 50%. It was shown that coarse grains and inclusions were the main types of defects. In the forging process, the refinement of coarse grains and crack initiation at inclusions were summarized respectively with respect to temperature, reduction ratio and multi-pass forging. The microstructure evolution of 30Cr2Ni4MoV steel is accompanied by the formation of fine grains on condition that multi-pass forging or an optimal reduction ratio of 10% is adopted at temperatures lower than 1000°C, while temperatures higher than 1100°C can lead up to coarse grains. Besides, cracks originate from CaO and FeS inclusions at 900°C and 1000°C related to intense shear stress and melting of the FeS-Fe eutectics distributing along grain boundaries.

scholarly journals Optimization of the Q-P Process Parameters for Low Alloyed Steels with 0.2% C

2014 ◽  
Vol 59 (3) ◽  
pp. 1205-1210 ◽  
Author(s):  
H. Jirková ◽  
L. Kučerová ◽  
D. Aišman ◽  
B. Mašek
Keyword(s):  
Carbon Content ◽  
Cooling Rate ◽  
Process Parameters ◽  
Microstructure Evolution ◽  
Retained Austenite ◽  
Pronounced Effect ◽  
Alloyed Steel ◽  
Austenitizing Temperature ◽  
Quenching And Partitioning ◽  
Cr Addition

Abstract In steels which are treated by the quenching and partitioning (Q&P) process, carbon content is one of the crucial parameters because carbon contributes greatly to stabilization of retained austenite and strengthens the material. In the present study, the Q&P process was gradually optimised for two low-alloyed steels with 0.2 % carbon content and with and without Cr addition. The results show that the cooling rate, as well as the austenitizing temperature, has a pronounced effect on microstructure evolution. The strength and elongation in the Mn, Si and Cr-alloyed steel was approx. 900 MPa and more than 30 %, respectively.

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