Thermal treatment of PM-tool steel alloyed with niobium

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 356; no. 1; pp. 200 - 207
• Main Authors: Pavlı́čková, M., Vojtěch, D., Novák, P., Gemperlová, J., Gemperle, A., Zárubová, N., Lejček, P., Jurči, P., Stolař, P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.09.2003; Elsevier
• Subjects: Applied sciences; Carbide; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Heat treatment; Materials science; Metals. Metallurgy; Niobium; Other heat and thermomechanical treatments; Other heat treatments; Physics; Powder metallurgy; Production techniques; TEM; Tool steel; Treatment of materials and its effects on microstructure and properties; Carbide; Powder metallurgy; Tool steel; TEM; Niobium; Austenization; Annealing; Heat treatment; Experimental study; Alloy steel; Hardening; Optical microscopy; Precipitation; Transmission electron microscopy; Tempering; Alloying; Microstructure; Carbides
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/S0921-5093(03)00120-5

The work is aimed at describing the influence of thermal treatment on the properties of a tool steel containing (in wt.%) 2.5% C, 3.3% Si, 6.2% Cr, 2.2% Mo, 2.6% V, 2.6% Nb, 1.0% W prepared by the powder metallurgy process. Alloying with niobium positively affects the microstructure, the mechanical properties and the performance of the steel. The microstructure of the hardened steel is composed of a martensitic matrix, retained austenite and various types of carbide. During tempering of the hardened steel at the temperatures above 480 °C precipitation of very fine carbides occurs, which results in secondary hardening. The optimum thermal treatment of the steel is austenitisation at 1050–1100 °C, nitrogen cooling and tempering at 540 °C (3×1 h).