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Title: Dynamic material modeling in hot forging

Abstract

A dynamic material model that characterized flow behavior in the workpiece under forging conditions was required to optimize the process and produce defect-free product at minimum cost. Constitutive equations describe the relationship between stress, strain rate, and temperature under forging conditions. Using aluminum alloy 7050, numerous deformation experiments were conducted to fully characterize constitutive equation variables. A thorough description of the experimental arrangement was provided. Flow data and efficiency data were assembled into a three-dimensional plot of temperature vs. strain rate vs. deformation efficiency to produce an efficiency map. The efficiency map provided the information required for optimization of forging process design. The results of dynamic modeling of the material were used in simulating the isothermal forging of a particular part. Recommendations concerning optimum preform design and processing conditions were reported.

Authors:
 [1]
  1. (Missouri Univ., Columbia, MO (United States))
Publication Date:
Research Org.:
Allied-Signal Aerospace Co., Kansas City, MO (United States). Kansas City Div.; Missouri Univ., Columbia, MO (United States)
Sponsoring Org.:
USDOE; USDOE, Washington, DC (United States)
OSTI Identifier:
5529716
Report Number(s):
KCP-613-4502
ON: DE92012109
DOE Contract Number:
AC04-76DP00613
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ALUMINIUM ALLOYS; FORGING; COMPUTERIZED SIMULATION; DEFORMATION; DYNAMICS; FLOW STRESS; MATHEMATICAL MODELS; PROGRESS REPORT; STRAIN RATE; TEMPERATURE DEPENDENCE; ALLOYS; DOCUMENT TYPES; FABRICATION; MATERIALS WORKING; MECHANICS; SIMULATION; STRESSES; 360101* - Metals & Alloys- Preparation & Fabrication; 990200 - Mathematics & Computers

Citation Formats

El-Gizawy, A.S.. Dynamic material modeling in hot forging. United States: N. p., 1992. Web.
El-Gizawy, A.S.. Dynamic material modeling in hot forging. United States.
El-Gizawy, A.S.. 1992. "Dynamic material modeling in hot forging". United States. doi:.
@article{osti_5529716,
title = {Dynamic material modeling in hot forging},
author = {El-Gizawy, A.S.},
abstractNote = {A dynamic material model that characterized flow behavior in the workpiece under forging conditions was required to optimize the process and produce defect-free product at minimum cost. Constitutive equations describe the relationship between stress, strain rate, and temperature under forging conditions. Using aluminum alloy 7050, numerous deformation experiments were conducted to fully characterize constitutive equation variables. A thorough description of the experimental arrangement was provided. Flow data and efficiency data were assembled into a three-dimensional plot of temperature vs. strain rate vs. deformation efficiency to produce an efficiency map. The efficiency map provided the information required for optimization of forging process design. The results of dynamic modeling of the material were used in simulating the isothermal forging of a particular part. Recommendations concerning optimum preform design and processing conditions were reported.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1992,
month = 3
}

Technical Report:
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  • A dynamic material model that characterized flow behavior in the workpiece under forging conditions was required to optimize the process and produce defect-free product at minimum cost. Constitutive equations describe the relationship between stress, strain rate, and temperature under forging conditions. Using aluminum alloy 7050, numerous deformation experiments were conducted to fully characterize constitutive equation variables. A thorough description of the experimental arrangement was provided. Flow data and efficiency data were assembled into a three-dimensional plot of temperature vs. strain rate vs. deformation efficiency to produce an efficiency map. The efficiency map provided the information required for optimization of forgingmore » process design. The results of dynamic modeling of the material were used in simulating the isothermal forging of a particular part. Recommendations concerning optimum preform design and processing conditions were reported.« less
  • The objective of this project was to develop and implement innovative die material and surface coating strategies such as composite dies and lubricated coatings to increase die lives and to reduce environmental pollution. In this project approaches and software were developed for die life optimization and optimal design of lubrication systems for hot forging. In addition, LENS applied nickel-aluminide coatings were developed and validated in the industrial environment for significant improvements in die life.
  • Equations were developed to express stress distributions for a variety of deformation configurations. Strain equations were developed as they apply to forged workpieces, as were strain rate equations. The flow stress equation was introduced. The shear criterion was established to minimize the amount of energy that deforming metal flow consumes. An equation was developed relating flash width and thickness using the concept of constant volume. Force equations were developed for lateral and converging flow. From these equations, the closed-die axisymmetric forging process was simulated in two cases: constant ram speed and constant strain rate. Fortran programs were developed for bothmore » cases. Software employed to present on-screen interactive graphics was FIGARO by MEGATEK. The feasibility of producing a particular part was studied by comparing net shape, near net shape, and conventional forging/machining methods. A near net shape design with some machining was recommended as most economical.« less
  • A computer process model provides a mathematically approximate description of the physical process of metal deformation. The most commonly used approximation method is the slab method.'' The slab method considers the stresses on a plane perpendicular to the direction of metal flow. When the forces on the slab are set at static equilibrium, the condition can be represented by a differential equation. By analytical or numerical integration of the differential equation, with appropriate boundary conditions, it is possible to calculate the forging forces. Application of the slab method to axisymmetric fie forging was divided into two stages: axisymmetric upsetting ofmore » the billet between dies; and radial flow to flash which starts after filling the die cavity. The modeling program was written in Fortran and integrated with computer graphics software FIGARO by MEGATEK.« less
  • Equations were developed to express stress distributions for a variety of deformation configurations. Strain equations were developed as they apply to forged workpieces, as were strain rate equations. The flow stress equation was introduced. The shear criterion was established to minimize the amount of energy that deforming metal flow consumes. An equation was developed relating flash width and thickness using the concept of constant volume. Force equations were developed for lateral and converging flow. From these equations, the closed-die axisymmetric forging process was simulated in two cases: constant ram speed and constant strain rate. Fortran programs were developed for bothmore » cases. Software employed to present on-screen interactive graphics was FIGARO by MEGATEK. The feasibility of producing a particular part was studied by comparing net shape, near net shape, and conventional forging/machining methods. A near net shape design with some machining was recommended as most economical.« less