Failure Analysis of Rocket Shell puncher Die

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Date

2016-08

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Addis Ababa University

Abstract

This paper studied Failure analysis of Rocket Shell punching die manufactured in Homicho ammunition and engineering industry having the crack on the surface of the male punching die. Detailed investigations including macroscopic examination, metallographic observation, and mechanical properties analysis were carried out. The investigations reveal that the failure mechanism of the punching die is fast brittle fracture caused by high stress under the condition of material self-embrittlement. As it is observed on 39 pieces of the puncher the main crack originated from the lower tip that has a direct contact with the hot of the punching die. The serious impact toughness degeneration and presence of impurities at the internal section of the die resulted in the material embrittlement. The hardness test and the oxidation process formed inside the material demonstrate that the site 1 and 2 has suffering high stress is the weak part of the die. Key words: Punching die, failure Analysis; Rocket shell: Fatigue failure; selfembrittlement; oxidation layer; heat treatment, crack zone

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Keywords

Punching die; failure Analysis; Rocket shell: Fatigue failure; selfembrittlement; oxidation layer; heat treatment; crack zone

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