Investigation of the pass geometry in compound backward forward extrusion process

مقدم أطروحة جامعية

Shihab, Iyad Fayiq

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة الإنتاج و المعادن

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2004

الملخص الإنجليزي

In this investigation, a compound process in extrusion by combination of forward rod and backward can is presented.

To investigate the effects of the geometrical variables in compound backward-forward extrusion on power requirements (experimentally and theoretically), flow pattern, relative flow quantity, and strain redundancy factor, different combinations of the geometrical variables were selected.

These combinations include four different reductions in cross-sectional area for backward extrusion (0.198, 0.319, 0.444 and 0.609) with flat head punch and three different forward reductions in cross-sectional area (0.395, 0.556 and 0.691) selected for the rod extrusion with flat faced and conical converging dies.

Five different profiles were selected for the punch head (60°.

90°; 120°, Hexagonal and Square) with a constant reduction in cross-sectional area (0.444) as well as to the circular shape.

On the other hand, there are five different die surface profiles designed on the basis of the theoretical die design, these profiles are (DCRHS, UCRHS, ACRHS, C-CRHS, and CMSR) with a constant reduction in cross-sectional area (0.556).

Commercially pure lead of (99.99 % Pb) is selected as a model material for the splatted extrusion billets of two semi cylindrical shape prepared for study of metal flow by Visio plasticity technique.

For results verification and comparison, UBET is proposed as a theoretical analysis method for predicting of power requirements for flat head punch and flat faced die geometry.

From the experimental results, it was found that there is a significant effect of the backward geometrical factors when they are combined with the forward factors, where the relations of load behavior, relative pressure, flow pattern, and strain redundancy will be more dearness than the effects of the forward factors.

On the other hand, it was shown from the flow pattern results that the profiled dies surfaces have an important effect in homogeneity of the material flow in forward direction.

The best results are achieved if a (0.444) backward reduction in area is used and when there is a combination between the conical punch head with (90°) cone angle combined with UCRHS or ACRHS die profile.

Although this investigation has presented an experimental study of the geometrical factors, there was a good agreement in results between the experimental and theoretical analysis.

التخصصات الرئيسية

الهندسة الميكانيكية

الموضوعات

• معالجة البيانات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305516