Metallurgy

Yes, you have some chances to get admission in IIT-Powai for doing engineering in metallurgy in these marks. Kindly apply for it as it is among the best institutes of engineering.

Hello Piyush,
Congrats for securing for a good rank in JEE Advance, if you have to choose between the above two options, definitely go for IIT Powai, for the reputation and also you can change branch after you score decent in first year.
All the Best!

You can pursue ME in materials engineering, nanotechnology or mechanical engineering in a few institutes. All these have difference scopes and job opportunities depending upon what college you choose for your Masters. Choosing between ME, MBA or civil services on the other hand depends upon you interest and your goal in life what you want to achieve, so choose wisely.

You may check manit site for the statical data. Complete placement statistics with percentage placement is provided there. About the scope, I would suggest metalurgy had a good scope but with a lot of work on itself. Conceding your marks if you have category or belong to home state still opt for a better branch in the collage. But if you have interest, metalurgy isn't a bad. Check out NIRF data too placed on site of college or NIRF site.

Dear,
Maths and physics have an important role in every B.Tech field and you should have strong foundation and Interest in maths to get the knowledge and skills to reach a good level.
All the best.

Absolutely, there will be good future if you study in NIT but for job opportunities, you should try abroad for better salary packages. You can get nice salary packages in North India.