The material flow stress model for 300M ultra high strength steel has been established by hot compression
tests on the Gleeble-1500 thermal simulation testing machine. The hammer forging forming for 300M ultra high
strength steel die forging of landing gear cylinder has been investigated by DEFORM 3D FEM software, the influence
of hammer forging under different process parameters has been researched in this paper. The results show that: the die
forging filled completely at 1 100℃ initial forging temperature after the three fires;the average stress of the forging is
228 MPa and the average strain is 1. 51, which provides technical reference for hammer forging process.