Low-alloyed steel with superior dry abrasive wear resistance and mechanical properties processed via steel mold casting

Abstract

Wear parts, such as tools, need to possess a combination of hardness, strength, and toughness along with high wear resistance. This study introduces a lean Fe94.2Cr0.3Mo0.4Mn1.5Ni3.0C0.6 (wt%) alloy specifically designed for cast wear parts. The research evaluates its microstructure, mechanical properties, and abrasive wear characteristics using various analysis methods. The chemical composition of the FeCrMoMnNiC alloy in combination with the applied steel mold casting lead to a microstructure composed of fine martensite (85 vol%) and austenite (15 vol%) as shown by quantitative analysis with X-ray diffraction. Quasi-static compression tests show pronounced work hardening from the compressive yield strength (σ_y0.2 = 1660 MPa) to the compressive strength (σ_cf = 5090 MPa) with good deformability (ε_max = 32%). For comparing the abrasive wear and mechanical performance, a commercially available martensitic steel was used as reference material. Abrasive wear studies using a SiC abrasive revealed a significantly lower wear rate for the novel alloy (5.9 ∙ 10⁻³ mm³(Nm)⁻¹) compared to the reference steel (14.2 ∙ 10⁻³ mm³(Nm)⁻¹), which is caused by the fine, multiphase microstructure. The predominant abrasive wear mechanism for the FeCrMoMnNiC was identified as micro ploughing. However, the wear traces also indicate micro cutting, and additional micro fatigue as consequence of repeated deformation. A friction-induced transformation from austenite to martensite was observed, evidenced by the reduced austenite content at the surface detected via grazing incidence X-ray diffraction and transmission-electron backscatter diffraction, which also showed surface deformation. These findings indicate, that the FeCrMoMnNiC alloy combining superior mechanical and wear properties, is a promising material for heavy industry wear applications.