High Performance Steels: Processing - Mechanical Property Relationships I
Sponsored by: TMS Structural Materials Division, TMS: Steels Committee
Program Organizers: Jonah Klemm-Toole, Colorado School of Mines; Ana Araujo, Vesuvius USA; C. Tasan, Massachusetts Institute of Technology; Richard Fonda, Naval Research Laboratory; Amit Behera, QuesTek Innovations LLC; Benjamin Adam, Oregon State University; Krista Limmer, Devcom Army Research Laboratory; Kester Clarke, Los Alamos National Laboratory
Wednesday 8:30 AM
March 22, 2023
Room: Aqua F
Location: Hilton
Session Chair: Jonah Klemm-Toole, Colorado School of Mines; Amit Behera, Questek Innovations
8:30 AM
Grain Growth and Precipitation Dissolution Modelling in the HAZ during Welding of Nb-Ti Steels: Iñigo Iturrioz1; Nerea Isasti1; Jose Rodriguez-Ibabe1; Pello Uranga1; Nobuyuki Ishikawa2; Daichi Izumi2; Douglas Stalheim3; David Jarreta4; David Martin4; 1CEIT and TECNUN (University of Navarra); 2JFE Steel Corporation; 3DGS Metallurgical Solutions; 4CBMM Asia
The production of modern high strength/high toughness linepipe steels is usually based on the hot rolling of low carbon Nb-Ti microalloyed steels. In this context, this study aims at developing a model able to predict austenite grain growth kinetics coupled to a precipitation dissolution model. This model was applied to the thermal paths in the heat affected zone (HAZ) during welding of pipes. Three titanium and niobium microalloyed steels with different initial precipitation states and microstructures resulting out of the hot rolling mill were selected. A numerical model based on the classical nucleation and growth theories was developed to predict the evolution of precipitates. This model will interact with a grain growth model based on Zener pinning and solute drag mechanisms. The resulting austenite grain growth kinetics are in good agreement with the laboratory data obtained for all the heat treatments.
8:50 AM
Investigating the Roles of Microstructure on High-temperature Creep Responses of Steels: Arul Kumar Mariyappan1; Ricardo Lebensohn1; Laurent Capolungo1; 1Los Alamos National Laboratory
The engineering components of ferritic-martensitic grade-91 steel alloys are widely used in energy sectors. These components are mostly operated at high temperature and low-to-moderate stresses and thus lead to thermal creep. Quantifying the effects of microstructure on high-temperature creep behavior is critical to minimizing the risks of failure. In this work, an advanced constitutive model within a mesoscale full-field elasto-viscoplastic Fast Fourier Transform (EVPFFT) framework is developed to capture the effect of stress, temperature, and microstructure on the creep responses of grade-91 alloy. Using this framework, the roles of the initial microstructure described in terms of dislocation density, precipitate content, and grain size on the creep responses are investigated. The effect of initial microstructure on the steady-state creep-rates and time-to-failure is found to vary significantly with stress and temperature. Further, using the model predictions, the variability in the experimental creep data is rationalized based on differences in the initial microstructure.
9:10 AM
Tensile Properties and Microstructures Development of Quenching and Partitioning (Q&P) Steels during Galvannealing Process: Lei Chen1; Kyeong Sik Shin1; Han Sol Maeng1; Chun Ku Kang1; 1Hyundai Steel
Quenching and Partitioning (Q&P) steels are regarded as one of the promising candidates for 3rd generation advanced high strength steels (AHSSs) for their lean alloy elements and excellent mechanical properties. TS (tensile strength) × EL (Elongation) product of the Q&P steels can reach a value above 20000 GPa∙% and are qualified for the manufacture of anti-intrusion parts to reduce the body-in-white weight of vehicles and to increase the passenger safety. However, galvannealing of Q&P steels faces many challenges. One of the big challenges for Q&P steel galvanizing is the mechanical property degradation during galvannealing due to the harsh process parameters compared to the original Q&P heat cycle. The present work applied galvannealing heat cycle with various modified parameters on two grades of Q&P steel, studied the effect of galvannealing process on the tensile properties and microstructures of the Q&P steels and proposed an optimized galvannealing process for Q&P steels.
9:30 AM Cancelled
The Role of Prior Austenite Grain Boundaries in Liquid Metal Embrittlement of B-added TBF Steels: Elahe Akbari1; Philipp Kürnsteiner1; Heiko Groiss1; Martin Arndt2; Martin Gruber2; Katharina Steineder2; Robert Sierlinger2; 1Christian Doppler Laboratory for Nanoscale Phase Transformations, Center for Surface and Nanoanalytics, Johannes Kepler University; 2voestalpine Stahl GmbH
Automotive advanced high-strength steels such as third-generation transformation induced plasticity assisted bainitic ferritic (TBF) steels with a Zn coating are prone to a detrimental failure known as liquid metal embrittlement (LME). LME frequently occurs during resistance spot welding while the steel is in contact with liquid Zn under stress, generating macroscopic cracks.This study aims to systematically investigate B-free and B-added microstructures to understand the effect of B on LME behavior of electro-galvanized TBF steels. Hot tensile tests indicated that the presence of B, even at minute concentrations, reduces LME sensitivity. Therefore, electron backscatter diffraction was conducted to reconstruct the prior austenitic matrix. This prior austenite grain reconstruction enables us to study the high-temperature microstructure at the time of LME crack generation. Transmission electron microscopy in conjunction with energy dispersive X-ray spectroscopy was carried out to analyze grain boundary chemistry, demonstrating differences in Mn concentration between the steel types.
9:50 AM Break
10:10 AM
Microstructure Evolution and Zinc Infiltration in an Advanced High-strength-Steel during Liquid-metal Embrittlement: Yuki Ikeda1; Hsu-Chih Ni2; Anirban Chakraborty3; Hassan Ghassemi-Armaki4; Jian-Min Zuo2; Reza Darvishi Kamachali1; Robert Maaß5; 1Federal Institute of Materials Research and Testing (BAM); 2University of Illinois Urbana-Champaign; 3ArcelorMittal Global Research and Development; 4General Motors R&D; 5Federal Institute of Materials Research and Testing (BAM), University of Illinois Urbana-Champaign
Despite the excellent mechanical properties and corrosion resistance of 3rd generation Zinc (Zn) galvanized advanced high-strength streels (3rd Gen. AHSS), liquid-metal embrittlement (LME) causes early failure. The origin of LME is linked to Zn penetrating into the grain-boundary (GB) network during joining, such as resistivity spot welding (RSW). However, the fundamentals of LME remain poorly understood. Due to the presence of several phases, including ferrite and austenite, complicated microstructural changes and Zn transport mechanism are expected due to the different chemical affinity of ferrite and austenite for Zn when heating exceeds the Ac3 temperature during RSW. Here we continue our work on tracking LME (Materials Today Advances 13, 100196, 2022) and the associated microstructural evolution in a 3rd generation AHSS. We use transmission electron microscopy (TEM) and 4D-Scanning TEM to identify the early stages of LME prior to cracking during interrupted welding. Thermodynamic simulations complement our experimental observations.
10:30 AM
New Tensile Specimens Optimized to Characterize the Localized PRW Weld Areas of ODS Steels: Mohamed Mabrouki1; Diogo Gonçalves1; Serge Pascal1; Denis Bertheau2; Gibert Henaff2; Angéline Poulon-Quintin3; 1Service d´Etudes Mécaniques et Thermiques (SEMT), CEA, Université Paris-Saclay, Gif-Sur-Yvette, France; 2Institut Pprime UPR 3346 ENSMA CNRS Université de Poitiers, F-86361 Futuroscope Chasseneuil, France; 3Université de Bordeaux, CNRS, Bordeaux INP, ICMCB, UMR 5026, F-33600 Pessac, France
Oxide Dispersion-Strengthened (ODS) ferrito-martensitic alloys are candidate materials for the fabrication of 4th generation nuclear reactor fuel cladding. These materials have optimal response to the loading conditions foreseen for these reactors (high temperature and irradiation doses), due to the homogenous dispersion of nano-oxides. The main objective of this study is to understand the effect of the pressure resistance welding (PRW) on the mechanical behavior of plug-clad assemblies. This solid phase welding process is known to limit the modification of the nano-oxides dispersion in the welded area compared to the fusion welding processes. In order to assess the mechanical strength of welded assemblies, we designed a specific tensile specimen that ensures stress localization at the weld joint using finite element simulations. The experimental tests are carried out at two different temperatures. The aim of this study is to characterize the mechanical property evolutions of the welded area.
10:50 AM
High Strength and Toughness Combination in Severe Plastically Deformed Martensitic and Austenitic Steels: Cafer Melik Ensar Acemi1; Matthew Vaughan1; Sezer Picak1; Robert Barber1; Ibrahim Karaman1; 1Texas A&M University
The role of grain refinement on the mechanical properties via a severe plastic deformation (SPD) technique known as equal channel angular pressing (ECAP) in three high strength steels is investigated. The steels studied in the present work are HY-100, a low carbon, low alloy martensitic steel known for its high yield and ultimate tensile strength widely used in various naval applications due to the combination of its high strength, weldability, formability, and corrosion resistance; AF9628, which is a newly developed high strength martensitic steel known for exceptional strength and toughness; and FeMnAl, an austenitic steel alloy known for its high strength to weight ratio due to the addition of Al, which reduces weight and increases precipitation hardenability. The selected number of ECAP passes, routes, and processing temperatures produced a variety of enhancements in mechanical properties for these materials where significant strengthening after ECAP via microstructural refinement is achieved.