The online test consisted of two parts. An aptitude/logical reasoning part with 60% weightage and a technical part with 40% weightage. The technical part mainly consisted of mechanical engineering related questions and fewer metallurgy related questions even though it was for metallurgy students. The aptitude part is fairly easy if you have some practice.
Though it was a technical interview, the interviewer also asked some HR related general questions from the questionnaire that was given to fill after the shortlisting for interview. The interviewer asked for subjects learned in B.Tech and asked some questions from many of the listed subjects (around 10 - 12). Maintaining a confident demeanor is important even though you don't know any answer.
The interviewer will ask general questions about yourself and your background alongwith your strengths and weaknesses. The rest of the interview will revolve around what you say for the first 5 minutes so speak wisely.
Never try to fool or stall any interviewer in any type of interview. They will see right through you. So always be confident and it's okay to accept that you don't know the answer for a particular question.