Deformation under hot working conditions

proceedings of the conference on "Deformation under hot working conditions" held at the Department of Metallurgy, University of Sheffield, on 5 and 6 July 1966

Publisher: Iron & Steel Institute in London

Written in English
Published: Pages: 189 Downloads: 568
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Subjects:

  • Metals -- Hot working -- Congresses.

Edition Notes

Includes bibliographies.

Statement[edited by W. J. McG. Tegart].
SeriesISI publication 108
ContributionsUniversity of Sheffield. Dept. of Metallurgy.
Classifications
LC ClassificationsTS200 .D34
The Physical Object
Pagination[10], 189 p.
Number of Pages189
ID Numbers
Open LibraryOL4051875M
LC Control Number79404021

Material processing techniques that employ severe plastic deformation have evolved over the past decade, producing metals, alloys and composites having extraordinary properties. Variants of SPD methods are now capable of creating monolithic materials with submicron and nanocrystalline grain. @article{osti_, title = {Handbook of metal-forming processes}, author = {Aritzur, B.}, abstractNote = {This book is essentially a collection of metal-forming processes. It provides studies of the modes of deformation in the workpiece and the external forces. Includes discussion of tool design and its geometrical parameters. forces is called deformation. • If upon removal of load the material reverts back to its initial size – elastic deformation. • If application and removal of the load results in a permanent material’s shape change – plastic deformation. • Fracture occurs when a structural component separates into two or more pieces. (1) Hot deformation of NIMONIC 80A was well-described by the sinh creep law with the stress exponent of and the activation energy of kJ/mol in the strain rate range of ~20 s-1 and the temperature range of ~ °C. Dynamic recrystallization fully occurred under these deformation conditions.

A quantitative Hardness technique in which a small indenter is forced into the surface of a materials to be tested under controlled conditions of load and rate of application. The depth or size of the resulting indentation is measured and related to a hardness number; the softer the material, the larger and deeper the indentation, and the lower. When compared to hot working tool steels, Sialons retain their hardness more efficiently at elevated temperatures (Figure 7) (7). They were developed to solve the difficulties involved in fabrication of silicon nitride. Figure 7: Comparison of hot hardness of ceramic die material (Sialon) and advanced hot working tool steel grades (7).File Size: 1MB. Compression test was carried out and the true stress-strain curves were obtained from the hot compression of alloy. A numerical simulation on the deformation behavior of aluminum alloy during the backward extrusion was also performed by finite element method. The results show that dynamic recrystallization occurs in the hot compression of alloy and the peak stress reaches Author: R. B. Mei, Y. X. Du, L. Bao, X. Y. Zhang, B. Zhang, Z. J. Zhou. The hot processing map of the alloy is established on the basis of hot deformation behavior and hot working characteristics. With the optimal thermal deformation conditions of to °C and to 10 s −1, the fine equiaxed grain and no holes are found in the matrix, which can provide significant guidance for hot deformation processing.

When plastic deformation occurs during hot or cold working, planes of atoms slip past each other, bringing about a change in the relative orientation and position of the atoms thus affecting the electric potential [2]. Usually, slip planes lies between and are parallel to the planes of greatest atomic density [3]. material under end-use conditions prior to specification is essential. Therefore, specific testing under actual conditions is recommended. Nothing contained in this book shall be construed as a grant of any right of manufacture, sale, use, or repro-. Chapter Process Design in Impression Die Forging / 3 temperature increases, grain growth occurs, and in some alloy systems, forgeability decreases with increasing grain size. The forgeabilities of metals at various deformation rates and temper-atures can be evaluated by using various tests, such as torsion, tension, and compression Size: 1MB. Disadvantages of Hot Working: v= velocity of ram at the start of deformation g= acceleration due to gravity p= air/ steam pressure on ram on down stroke. 7 Under the equilibrium conditions, the summation of forces acting in a longitudinal direction must be zero.

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Get this from a library. Deformation under hot working conditions book under hot working conditions; proceedings of the conference on 'Deformation under hot working conditions' held at the Department of Metallurgy, University of Sheffield, on 5 and 6 July.

[University of Sheffield. Department of Metallurgy.;]. Deformation under hot working conditions: Proceedings of the confernece on 'Deformation under hot working conditions' held at the Department of Metallurgy (Iron & Steel Institute.

Publications, ) on *FREE* shipping on qualifying offers. Thus, under hot-working conditions an increase in deformation temperature at constant strain rate (a decrease in Z) leads to a decrease in the flow stress, whereas an increase in strain rate at constant temperature (an increase in Z) gives rise to an increase in flow stress and the displacement of the stress–strain curve to higher stress by: The deformation parameters have little effect on the constant m, typically will range between one and two, and are mostly dependent upon the steel composition, however the 50% recrystallization time is greatly affected and can change by an order of magnitude dependent upon the conditions that occur during the hot rolling period.

Working under these cyclic high thermal and mechanical load conditions, hot forging dies mainly show abrasive wear, mechanical fatigue, thermal fatigue, and plastic deformation [7]. Dynamic recrystallization (DRX) is a type of recrystallization process, found within the fields of metallurgy and geology.

In dynamic recrystallization, as opposed to static recrystallization, the nucleation and growth of new grains occurs during deformation rather than afterwards as part of a separate heat treatment.

The use of a constitutive equation which expresses the flow stress of the material in terms of the applied strain, rate of straining, and deformation temperature to calculate the power dissipation efficiency of the material(η) deformed under hot-rolling conditions has shown that it could be strongly strain dependent, particularly toward the Cited by: Analysis of Deformation Characteristics of Magnesium AZ80 Wrought Alloy under Hot Conditions where D 1 and D 2 are the axis of ellipse in two different directions (see Fig.

7) and D 0 is an. Deformations measure a structure’s response under a load, and calculating that deformation is an important part of mechanics of materials. Deformation calculations come in a wide variety, depending on the type of load that causes the deformation.

Axial deformations are caused by axial loads and angles of twist are causes by torsion loads. The elastic [ ]. ), the main difference between hot working and creep being the strain rate. Hot working is generally carried out at strain rates in the range of 1– s 1, whereas typical creep rates are below 10 5 s 1.

Nevertheless, in many cases similar atomistic mechanisms occur during both types of deformation. Dynamic recrystallization.

Under conditions of heavy loads, sufficient to induce plastic deformation. -Light and Elastic- friction is directly proportional to the applied pressure with the proportionality constant.

-At high pressures- friction becomes independent of contact pressure and is more closely related to the strength of. Design of Forming Processes: Bulk Forming Chester J. Van Tyne Colorado School of Mines, Golden, Colorado, U.S.A.

BULK DEFORMATION atures relative to the melting point of the metal. Hot working occurs at temperatures above tJlle recrystalliza-tion temperature of the metal. There is a third temper. Deformation processes can be conveniently classified into bulk-forming processes (e.g., rolling, extrusion, and forging) and sheet-forming processes (e.g., stretching, flanging, drawing, and contouring).

In both cases, the surfaces of the deforming material and of the tools are usually in contact, and friction between them has a major influence. Hot working is plastic deformation which is carried out under conditions of temperature and strain rate such that substantial recovery processes occur; thus large strains can be achieved with essentially no strain hardening.

Hot working is normally performed at a temperature >T m and high strain rates in the range of – s −1. In engineering, deformation refers to the change in size or shape of an object. Displacements are the absolute change in position of a point on the tion is the relative change in external displacements on an is the relative internal change in shape of an infinitesimally small cube of material and can be expressed as a non-dimensional change in length or angle of.

Summary. A comprehensive treatise on the hot working of aluminum and its alloys, Hot Deformation and Processing of Aluminum Alloys details the possible microstructural developments that can occur with hot deformation of various alloys, as well as the kind of mechanical properties that can be anticipated.

The authors take great care to explain and differentiate hot working in the context of. Describing the effects of temperature and strain rate on the evolution equation through Zener-Hollomon parameters, a database was constructed for use in computer models to predict the roll force of rolling or forging loads under hot working conditions.

Keywords:. 1. During deformation at a constant temperature above Tm, there is a steady-state regime where both stress and strain rate remain constant independent of strain.

The interdependence of stress, strain rate and temperature during steady-state hot working and secondary creep are similar.

During the hardening stage, simultaneous dynamic recovery causes the dislocations to arrange into Cited by: 8. the homogeneous deformation of an initially uniform material to lead to a bifurcation point, at which non-uniform deformation can be incipient in a planar band under conditions of continuing equihbrium and continuing homogeneous deformation outside the zone of localization.

The type of dynamic recrystallization process during the high-temperature deformation under different conditions has been identified through the analysis on the dislocation evolution involving with recrystallized grains growing.

And the dependence of the type of dynamic recrystallization on the deformation parameters has been discussed. The conditions with lower temperatures and higher Author: HouQuan Liang, HongZhen Guo, Yang Nan, ZeKun Yao, WeiJian Tu.

Titanium alloys being hot formed. The video is reproduced with the kind permission of David Peacock of the Titanium Information Group. uminf. °F), prior to hot mechanical working (such as forging) for a long period, a deterioration in the room-temperature mechanical properties (particularly tensile ductility and impact strength or toughness) can be obtained after the steel has been given a final heat treatment (comprising reaustenitizing, quenching, and tempering) (Ref ).

Since deformation theory could be considered a central topic in algebraic geometry textbook where some of the main results and methods are collected in one place is certainly welcome. inclusion of exercises and plenty of examples, make this book suitable for a course on this topic or for self-study, with the only prerequisite the now 5/5(1).

Hot Deformation and Processing of Aluminum Alloys. Hot Deformation and Processing of Aluminum Alloys book. to reduce loads with the large machinery required, hot working is employed to lower the §ow stress and improve the ductility []. For secondary processing to near-net shape, cold, lubricated, cleaned objects are formed with Author: Hugh J.

McQueen, Stefano Spigarelli, Michael E. Kassner, Enrico Evangelista. •It is a time- dependent deformation under a certain applied load. •Generally occurs at high temperature (thermal creep), but can also happen at room temperature in certain materials (e.g.

lead or glass), albeit much slower. •As a result, the material undergoes a time dependent increase in length, which could be dangerous while in service. The material behaviors of two types of bearing steels at hot working conditions are investigated. Stress-strain curves at various temperatures (–°C) and strain rates (1–50/s) are obtained by compression tests with a computer controlled servo-hydraulic Gleeble testing by: The experimental stress–strain data from isothermal hot compression tests, in a wide range of temperatures (– °C) and strain rates (– s −1), were employed to develop constitutive equations in a commercially pure aluminum (AA).The effects of temperature and strain rate on the hot deformation behavior were represented by Zener–Hollomon parameter including Arrhenius by: 9.

Get this from a library. Hot deformation of aluminum alloys III: TMS Annual Meeting, San Diego, California, MarchGrain Refinement in As-Cast Aluminum Alloy Under Hot Deformation --Static Recrystallization in Al Alloys After Hot Working \/a>> # Hot deformation of aluminum alloys III: TMS. Figure Engineering stress-strain diagram for hot-rolled carbon steel showing important properties (Note, Units of stress are psi for US Customary and MPa for S.I.

Units of strain are in/in for US Customary and m/m for S.I. Other materials exhibit stress-strain curves considerably different from carbon-steel although still highly Size: KB.

• Strain hardening or cold working is the phenomenon of increasing hardness and strength of the a ductile material as a result of plastic deformation at temperatures far below its melting point. • Indeed, plastic deformation leads to the multiplication of dislocations, which.

@article{osti_, title = {Texture and microstructure development in Al-2%Mg during high- temperature deformation}, author = {Chen, S R and Kocks, U F}, abstractNote = {The high rate sensitivity of the flow stress that is exhibited by alloys under solute drag control, such as Al-Mg at high temperatures, influences texture development because more slip systems contribute to deformation.Plasticity, microstructure and mechanical properties of titanium alloys depend on hot working conditions (Peters et al., ; Brooks, ): heating rate, time and temperature of soaking and furnace atmosphere, start and finish temperature of deformation, draft in final operations of deformation, strain rate, cooling rate after by: 3.The behaviour of plain carbon as well as structural steels is qualitatively different at different regimes of strain rates and temperature when they are subjected to hot-working and impact-loading conditions.

Ambient temperature and carbon content are the leading factors governing the deformation behaviour and substructural evolution of these : B. Gangadhara Prusty, Amborish Banerjee.