Hi Praveen, cutoff for various PSU varies every year based on the merit list, number of test takers, number of vacancy and difficulty levels of exam etc. However by the past records, for SC category, some of the PSU chances are, 

1) BSNL 

2) BEML, can be a very close call as their cutoff is around 50 

3) CEL 

4) NTPC, is also close chances as cutoff is around 49-50 

5) BBNL 

You can refer to our link, which contains a detailed cutoff list for each and every PSU, 

https://engineering.careers360.com/articles/what-are-gate-scores-for-psu-recruitment