|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Mechanical Characteristics and Application Properties of Metals and Non-metals for Technology: An EPD Symposium in Honor of Donato Firrao
||Integration of Metallography, Fractography and Mechanical Properties Tests as a Key to Failure Analysis of Quenched and Tempered Large Steel Components
||Donato Firrao, Paolo Matteis
|On-Site Speaker (Planned)
Quenched and tempered thick steel components are characterized by large microstructural variations between surface and core, due to different mixed microstructures occurring already after quenching. To perform failure analysis of a cracked large die for plastic components, fabricated with quenched and 550°C tempered steel grade 1.2738 (40CrMnNiMo8-6-4), a bloom of such a steel, similarly heat treated, was analyzed at different depths; whereas at surface tempered martensite predominates accompanied by residual austenite transformed during tempering, at increasing depths lower bainite modified by tempering appears alongside the transformed residual austenite, to be progressively substituted by modified upper bainite and by fine pearlite, predominant at core. Hardness continuing decreasing towards the core, KIc values rather low were determined from surface to core, where slightly higher toughnesses (47 MPa√m) than at surface (36 MPa√m) occurred. Fracture modes were mixed cleavage and intergranular fracture at surface with increasing ductile rupture areas at larger depths.
||Planned: Supplemental Proceedings volume