Preparation method of low-expansion iron-nickel alloy 4J36 plate

The invention belongs to the technical field of alloy manufacturing, and discloses a preparation method of a low-expansion iron-nickel alloy 4J36 plate, which comprises the following steps: smelting by adopting a converter, smelting by adopting a vacuum refining method, and then continuously casting to obtain a continuous casting blank; and rolling is conducted according to the thickness of a finished product, the initial rolling temperature is 1050-1090 DEG C, the process is controlled, the rolling rhythm is reduced, and the final rolling temperature is smaller than or equal to 850 DEG C. According to the method, precise component control is achieved, and the purity is good. The problems that when the invar alloy 4J36 continuous casting billet with the thickness of 200 mm or above is heated and rolled at a time, the surface is oxidized and burnt seriously, the core part is heated insufficiently, deformation is uneven in the rolling process, head warping is prone to occurring, smooth rolling is affected, and