The effe of die profiles on combined for word backward extrusion process

Dissertant

Salih, Ali Hasan

University

University of Technology

Faculty

-

Department

Department of Production Engineering and Metallurgy

University Country

Iraq

Degree

Ph.D.

Degree Date

2008

English Abstract

In this study the effect of die profile and type of punch ( shape and size ) on the parameters in the combined forward (rod) - backward (can) extrusion process is investigated numerically using FEM and expert mental program which involves the investigation of the friction condition according to the principle of tip test Three groups ol dies were used* The firsL group contained five dies which have the same reduction area (o.555) and the profiles of them were designed on the basis of the rational die design, their profiles were ( ACRHS, DCRHS? UCRHS.

C-CRHS and CMSR ).

The second group contained three conical dies with same conical angle (tr = 30°) , but tliliferent reduction areas (0.691, 0.555, GJ95).

The third group contained three ;lat dies which have the same reduction area of conical dies.

The corresponding punches are the circular flat head with the reduction areas (0.30M, 0.444 and 0.605), 0.444 with cone angles (60°, 90° and 120°), and polygonal heads (hexagonal and square).

Commercial Aluminum (1061 - 1) billets were used in this study The results show that the die [ACRHS) with cone punches of 60° &.

90* prism angle and the die (CMSR) with cone punch of 120° prism angle give the minimum value of relative extrusion pressure.

While with all Hat punches the die (UCR1 IS) give the min, value.

Also, reduction area of flat and conical dies has an effect on the value of relative extrusion pressure that the min.

value was found with reduction area (0.391).

The cross sectional area of head flat punch has a little effect on the exmision pressure with rational dies that the maximum difference between its values was 4.5% .

The polygonal punches have a different effect on the extrusion parameters according to the number of sides and type of die.

The less value of max.

effective stress was found with cone punch of prism angle 120° among cone punches for all rational dies except (CMSR) and conical dies except the die of reduction area (0.555) where the values of max.

stress were increased with mean ratio 64,05% at the other cone punches with those dies .

For all flat dies the cone punch of 90° prism angle gave less max.

stress than other conc punches where the max.

stress was increased at them with mean ratio 45.5% .

Flat punch of reduction area (0.444) among the flat punches gave less value of max.

stress with rational dies (ACRHS , C-CRHS and CMSR) , also with al! conical dies and flat die of reduction area where the values of max, stress increased from 24.26% to ! 90.29% in the other flat punches .

The Jess value of max.

strain was found at cone punch of 120° prism angle with the rational dies (ACRHS ? UCRHS and C-CRHS) and the max.

strain increased with other cone punches from 36.4% to 113.9% .

Cone punch of 60° prism angle gave less value of max.

strain with ail flat dies and max.

strain increased in the other cone punches with mean ration 53.48% .

Fiat punch of reduction area 0,444 among flat punches gave less value of max.

strain with all rational dies except (CMSR) and with conical and flat dies except the dies of reduction area 0.395 and 0.4591 respectively where the values of max.

strain increased in other flat punches with mean ratio £3.6% , ll has been noted that the die profile had another effect on the value of shear friction factor which was changed through the simulation to determine the metal flow jength which was obtained experimentally at constant stroke

Main Subjects

Materials Science , Minerals

Topics

• Minerals

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-305636