Manufacturing Technology Today

Tarun Nanda ¹, Nitin Singla ²

Affiliations
1 Mechanical Engg Dept., Thapar University, Patiala, IN
2 Mechanical Engg. Dept., Chitkara Institute of Engg. and Technology, Rajpura, IN

Abstract

Under dynamic load conditions, toughness becomes the most important mechanical property. Some of the main factors which control weld metal toughness include flux basicity, wire chemistry, post weld heat treatment and welding heat input. The present research describes the experimental work carried out on 12 mm thick mild steel plates butt welded (with double V-groove) using submerged arc welding process. The main objective of the study is to establish correlations (using method of least squares) between the input welding variables (viz. welding current, arc voltage, welding speed) and the output variable i.e. the impact strength of the joints at ambient temperatures. The outcome of this study is beneficial in predicting the range of toughness values (Charpy-V notch) of the welded joints prior to actual welding, thus saving experimental resources as well as time and thus enhancing the productivity of the welding process. The study reveals that increased heat input rates result in low Charpy-V impact values (owing to presence of pro-eutectoid ferrite and upper bainite) whereas low heat input rates tend to increase the impact values (due to the interlocking acicular ferrite structure).

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Tarun Nanda ¹, T. P. Singh ¹

Affiliations
1 Mechanical Engg. Dept., Thapar University, Patiala, IN

Abstract

Small scale manufacturing industry (SSMI) is a very important sector of our economy. It contributes almost 40% of the gross industrial value added to the Indian economy and about 45% of the Indian exports. Small scale units offer high employment potential and have low capital-output and capital-labor ratios. These characteristics make small scale sector very significant in a capital scarce and labor abundant economy like India. Though there has been a conspicuous increase in the number of small scale units, industrial sickness in this sector has assumed very serious proportions. Many causes account for the sickness. The present work discusses the results of a survey conducted in 93 small scale industries. The main factors impairing the performance of machine tool, cutting tool and auto-component industry have been identified and discussed. The survey also analyzes the extent of government support to the industry in its technology development initiatives.

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