Low-carbon high-Cr alloy steel billet connecting and rolling method

The invention discloses a low-carbon high-Cr alloy steel billet connecting and rolling method. One end of a low-carbon high-Cr alloy steel billet is machined into a mortise groove, and one end of a 30CrMoA continuous casting billet is machined into a tenon; the two steel billets are connected together through two low-carbon steel pins which are arranged in parallel at intervals, single-side bevels are formed in the mortise and tenon connecting parts and the pin connecting parts, and the steel billets are connected and fastened in the circumferential direction through mortise and tenon structures and welded and fixed steel billets; during rolling, one end of a low-carbon high-Cr alloy steel billet of the connecting piece firstly enters a rolling mill, one end of a 30CrMoA continuous casting billet enters the rolling mill to be rolled, it is guaranteed that the hard low-carbon high-Cr steel billet is rolled by the rolling mill firstly, then the 30CrMoA continuous casting billet is rolled in an extending mode, a