25-27 April 2022
Conventum Conference Center
Europe/Vienna timezone

Thermal fatigue behaviour of AISI H13 hot work tool steel produced by Direct Laser Metal Deposition

26 Apr 2022, 17:10
20m
Room 2

Room 2

Oral Presentation Fatigue under mechanical & thermal cyclic loads Fatigue under Mechanical & Thermal Cyclic Loads

Speaker

Dr Daniel Massignani (University of Trento)

Description

Direct Laser Metal Deposition (DLMD) is an additive manufacturing technique getting growing attention thanks to the possibility to produce very complex parts in short time and in a cost-effective manner. Possible applications of this technology are tools with conformal cooling channels and claddings for dies and moulds reparation. AISI H13 is a hot work tool steel, typically used for hot forming applications like die-casting tools, extrusion dies due to its high toughness and hot yield strength. One of the damaging mechanisms of tools is thermal fatigue (TF) cracking, leading to surface deterioration, and consequently also of the processed parts.
In this work the TF behaviour of DLMD-H13 submitted to two different heat treatments, namely direct tempering (T) and a quenching and tempering (QT), was investigated. Due to the different starting microstructure, as-built and Q samples had to be tempered to different temperatures to achieve the same target hardness for T and QT samples. T did not significantly change the solidification microstructure after DLMD, and microsegregation was present. On the other hand, QT produced a homogenous martensitic microstructure, since austenitizing partially amended the original solidification microstructure.
A customary laboratory test was developed to induce TF damage under a cyclic temperature variation between 630°C and 60°C. The total length of the cracks, cracks density, surface and hardness profiles, depth of cracks have been measured to evaluate the TF behaviour of H13 heat treated according to the two variants. The TF tests evidenced that the T-H13 has a slightly better TF resistance respect QT-H13, due to the higher tempering resistance of T-H13 respect to QT-H13. Thus, according to TF test results, direct tempering can be preferred to the quench and tempering, since the elimination of quenching can decrease the costs of production as well as distortions related issues, increasing the competitiveness of DLMD.

Speaker Country Italia

Primary author

Massimo Pellizzari (University of Trento, Dpt. Industrial Engineering)

Co-authors

Dr Daniel Massignani (University of Trento) Dr Sasan Amirabdollahian (University of Trento)

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