Abstract:
Industrial sector of Bangladesh has to depend entirely on some impolted spare
parts, but it requires long lead time for there procmement. This leads to huge
inventoty cost and lot of spares are kept in reserve in the fear of factory shut downs.
Allen key Bolts and Nuts are critical spare parts in ceramic industry which has high
usage value. 11le quality of allen key bolts and nuts found in the local ma.rket are
of very poor. As an attempt to solve this problem the present work wa.s perfonned.
Under this work a comperative study of the local and impotted spa.res patts were
conducted. Chemical analysis, Vickers hardness, Proof Stress, Microstmcture of
the materials of these parts were studied. Apatt Hom that the different pat'ameters of
thread of local and import.ed samples are analysed. From the analysis main causes
of failure of the local samples at'e identified, suitable materials at'e selected and
manufacturing process are developed fl)r their manufacturing. Some Allen key
Bolts atld Nuts at'e matlufactured on experimental basis. Different combination of
heat treatment such as pack carburizing at different period of time and quenching
are petfOl1ned on both locally available and matlUfilctured satnples. 11le proof
stress of these samples are checked for quality standard. It was observed that proof
stress is increased with the increase of carburizing period for matlUfactured samples
but in the case of local samples proof stress is decreased with the increase of
cat'burizing period. For mailufactured samples tlle pJ'oof stress was found within
acceptable limit. Economic analysis was pedi)nned to evaluate viability of
matlUfactut1ng tlle spare locally and it was found that local manufacture of spare
parts with the target properties is economically viable and the country save a lot of
foreign exchatlge.
