In order to reduce powder temperature to lower than 100 ℃ in warm compaction by changing polymer lubricant design, powder flowability, warm compacting behavior, lubricating mode as well as ultimate tensile strength after sinter-hardening and tempering were investigated systematically. By means of low temperature warm pressing and sintered hardening technique, samples with the sintered densities of 7.40-7.45 g/cm3 and the strengths of 950-1 390 MPa are achieved as the early compacting pressure is 686-735 MPa.