If you have all files but they are damaged, use the Repair archive tool in WinRAR (Alt+R). To give you a better report, could you tell me: What is the source or content of this file? Are you getting a specific error when opening it?
Once I know this, I can tell you exactly which tool you need to open it. How to Extract Part .RAR Files (Full Guide) B1.part2.rar
Here is a report on how to handle, extract, and troubleshoot this file: Technical Overview Part 2 of a Multi-volume RAR Archive. If you have all files but they are
Requires B1.part1.rar to be in the same folder to function. How to Extract/Open B1.part2.rar