Hot Working Tool Steel with Bainitic Microstructure—The Mechanical Properties at Elevated Temperature. Issue 4 (29th December 2022)

• Record Type: Journal Article
• Authors: Krull, Hans-Günter; van Soest, Frank; Niederhofer, Philipp; Schneiders, Till
• Other Names: Asnafi Nader guestEditor.
• Is Part Of: Steel research international. Volume 94:Issue 4(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-12-29
• Subjects: additive manufacturing -- bainite -- in-service temperature -- micro-structures -- precipitation hardening -- steel properties; Steel -- Periodicals; Steel -- Metallurgy -- Periodicals; 669.142
• DOI: 10.1002/srin.202200329
• Languages: English
• ISSNs: 1611-3683

Abstract

Abstract : Usually, tool steels are used in quenched and tempered conditions. Due to the phase transition from austenite to martensite and the volume change during the transformation, controlling distortion might be challenging. A newly developed steel focusing on a bainitic structure, even for bigger dimensions, shows a lower hardness at ambient temperature than conventional hot working tool steels but with a lower temperature dependency. Therefore, at service temperature, the mechanical properties are comparable to established grades. Heat treatment is simplified by a simple austenitization and cooling process without special requirements on the cooling rate. Due to a generally lower cooling rate and lower hardness compared to a quench and tempering process, the risk of cracking is reduced while machinability is improved. With the combination of good weldability and rather low hardness after rapid cooling, this grade can also be processed in additive manufacturing and is well suited for a hybrid process of conventional and additive manufacturing. Abstract : A new tool steel with a bainitic microstructure is presented in this study. The low hardness due to a rather carbon content compared to standard tool steel leads to good machinability. At elevated temperatures, the decrease in yield strength is very low, and therefore the mechanical properties at in‐service temperatures are comparable to usually used ones.