Hello student cut off vary every year on various factors like the level of question in the entrance examination and total number of applicants in that examination, as per previous year records its expected that you need to secure rank around 70 (SC category). Last year the cut off for CSE was 72(sc category).

For more updates refer to the link mentioned below - https://www.google.com/amp/s/engineering.careers360.com/articles/jee-advanced-cutoff-for-iit-kharagpur/amp

Feel free to comment if you have any doubt

Good luck