The designed tested steels (steel 0.45C-12. 5Cr-0. 41 Mo-0. 22V and steel 0. 85C-10. 5Cr-0. 91 Mo-0. 25V) are melted by a 50 kg vacuum induction furnace and forged to tested specimen. The effect of quenching temperature (950 ~ 1 150 ℃),tempering temperature (once tempering at 200 ~ 400 ℃. and double tempering at 500 ~ 600 ℃)on structure
strength
elongation
hardness and impact energy of steels is tested and studied. Results show that the properties of steel 0.45C-12.5Cr-0.41 Mo-0. 22V quenched at 1 050 ℃+ double tempered at 500 ℃ are best: tensile strength 1712.3 MPa
yield strength 1 476.5 MPa
elongation 7. 8%
HRC hardness value 69. 3 and impact energy 7. 3 J. The hardness value of die steel increases by secondary hardening
but during tempering process the carbides in steel grow up with uneven distribution easily led to impact toughness of steel decreasing. The strength index of tested new stainless die steels is high than that of normal commercial die steel 42Gr3 Mo2MnVl.