Two dimensional (2D) metal carbides are attractive owing to their unique structures and promising applications. Herein, we propose a one-step compressive route to grow 2D iron carbide, challenging the dominant exfoliation approach. First-principles simulation showed that artificial compression can drive directional migration of Fe, Cr, and C atoms, which asynchronously accumulated to form 2D hexagonal iron carbide with a stable interplanar distance of 0.39 nm, similar to the structure of 2D graphene. The microhardness of 2D hexagonal iron carbide was 652HV, which is 1.2 times that of original orthorhombic iron carbide (560HV). Deformation of (Fe,Cr)3C was facilitated by the metallic character of the Fe-C and Cr-C bonds. Collaborative deformation of Fe-C and Cr-C bonds played an important role in the orthorhombic to hexagonal evolution of iron carbide in white cast iron. This approach will stimulate some new ideas for the controllable growth of high-quality 2D materials.