Optimizing Cryogenic Treatment Temperature for Enhanced Wear and Mechanical Properties of High‐Chromium High‐Vanadium Cold Work Steel

This study examines the influence of cryogenic treatment (CT) on the microstructure, mechanical properties, and sliding wear behavior of high‐chromium high‐vanadium cold work steel (HCHV steel). Specimens are austenitizing at 1000 °C, cryogenically treated at −50, −100, or −150 °C for 2 h, tempered at 270 °C, and characterized by X‐ray diffraction Rietveld refinement, scanning electron microscope, electron probe microanalysis, electron backscatter diffraction, and focused ion beam–transmission electron microscopy (FIB‐TEM); dry sliding tests are conducted using a reciprocating ball‐on‐disk configuration against Si 3 N 4 balls in accordance with ASTM G133‐05. CT at −50 °C produces a martensite content of 58.7%, a hardness of 65.1 HRC, a compressive strength of 3253 MPa, an impact energy of 5.5 J, and an ≈35% reduction in specific wear rate compared with the untreated condition. In contrast, the −150 °C treatment induces carbide agglomeration and martensitic embrittlement, whereas the untreated steel contains excessive retained austenite and coarse carbides. The −50 °C condition also exhibits the highest fraction of postwear high‐angle grain boundaries (56.2%) and a moderate amount of metastable retained austenite that transforms by the transformation‐induced plasticity (TRIP) effect during sliding. Overall, a moderate cryogenic temperature of −50 °C refines the MC carbide dispersion and optimizes retained austenite stability, providing the best combination of hardness, strength, toughness, and wear resistance in this HCHV steel.