The invention relates to an ultrahigh-strength TiCN-base Co-containing steel-bonded hard
alloy threading tool capable of
coating and a preparation method. The preparation method is characterized by comprising the following steps that the ultrahigh-strength TiCN-base Co-containing steel-bonded hard
alloy threading tool takes Co-containing Fe-Mo-Cr
alloy steel as a matrix, and TiCN with the
mass fraction of 20-35% is added as a hard phase; the surface of
powder is activated by adopting the method that quantitative preoxidation
oxygen aeration is carried out after high-energy ball milling, the
sintering activity of the matrix is improved, then the
oxygen content (less than 800 ppm) is reduced substantially by a carbon and
oxygen reduction reaction in the
sintering process, and the
sintering temperature is reduced; and the
tempering resistance, the PVD
coating property, the strength and the
toughness of the ultrahigh-strength TiCN-base Co-containing steel-bonded hard alloy threading tool are improved by leading in a strengthening element of Co. The ultrahigh-strength TiCN-base Co-containing steel-bonded hard alloy threading tool has high strength (2800-4000 MPa) and high
toughness (alpha k is equal to 7-15 J / cm2, KIC is equal to 20-28 MPa.m1 / 2), the limitation that a traditional steel-bonded hard alloy is only used for mid-and-low-end wear-resistant pieces can be broken through, and threading tools such as a PVD
coating and squeezing screw tap and a
cutting screw tap which are more wear-resistant than high-speed steel and are more edge-breaking-resistant than hard alloy are prepared.