Topic
Hot working
About: Hot working is a research topic. Over the lifetime, 4512 publications have been published within this topic receiving 70521 citations.
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TL;DR: In this paper, a critical review on some experimental results and constitutive descriptions for metals and alloys in hot working, which were reported in international publications in recent years, is presented.
1,071 citations
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15 Jan 2002-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the effects of impurities and dispersoids on the constitutive equations for Al alloys are briefly discussed and compared with carbon, micro-alloyed, tool and stainless steels and to ferritic steels which usually do not exhibit DRX.
Abstract: Constitutive equations including an Arrhenius term have been commonly applied to steels with the objective of calculating hot rolling and forging forces. The function relating stress and strain rate is generally the hyperbolic-sine since the power and exponential laws lose linearity at high and low stresses, respectively. In austenitic steels, the equations have been used primarily for the peak stress (strain) associated with dynamic recrystallization (DRX) but also for the critical and steady state stresses (strains) for nucleation and first wave completion of DRX. Since the peak strain is raised by the presence of solutes and fine particles, the stress is raised more than by simple strain hardening increase, thus causing a marked rise in activation energy in alloy steels. In contrast, large carbides, inclusions or segregates, if hard, may lower the peak strain as a result of particle stimulated nucleation. Due to the linear relation between stress and strain at the peak, flow curves can be calculated from the constitutive data with only one additional constant. Maximum pass stresses can also be calculated from a sinh constitutive equation determined in multistage torsion simulations of rolling schedules. Comparison is made between carbon, micro-alloyed, tool and stainless steels and to ferritic steels which usually do not exhibit DRX. Parallels to the effects of impurities and dispersoids on the constitutive equations for Al alloys are briefly discussed.
892 citations
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TL;DR: In this paper, a set of phenomenological, internal variable type constitutive equations describing the elevated temperature deformation of metals is developed, which can faithfully account for strain-hardening, the restoration processes of recovery and recrystallization and strain rate and temperature history effects.
523 citations
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TL;DR: The main feature of hot working is that extremely large strains are applied to materials at high rates of strain at temperatures above ∼ 0.6Tm, where Tm is the melting temperature in degrees Kelvin this article.
Abstract: The main feature of hot working is that extremely large strains are applied to materials at high rates of strain at temperatures above ∼ 0.6Tm, where Tm is the melting temperature in degrees Kelvin. Strength and ductility under these conditions are markedly dependent on both temperature and rate of straining. Although this review is confined to strength and structure during hot working, ductility is intimately related to the deformation processes that govern plastic flow. This aspect has been recently reviewed by one of the authors. These large strains can be achieved with little or no strain-hardening, indicating that dynamic softening processes can operate sufficiently rapidly to balance the strain-hardening processes. In this situation, the structural changes involved can be used to obtain information on the mechanism of deformation. However, as emphasised later, care must he taken in the interpretation of such hot-worked structures, since significant structural changes can occur on holding at ...
517 citations
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TL;DR: In this paper, it is established from metallographic and flow stress observations that dynamic recrystallization occurs at strains greater than a critical value and results in a recrystized grain size which is determined entirely by the flow stress.
498 citations