High Performance Steels: Poster Session
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
Tuesday 5:30 PM
March 21, 2023
Room: Exhibit Hall G
Location: SDCC
Bridging the Precipitation Behaviour and Mechanical Properties of Cu-Ti Modified Quenched and Tempered Steel: Kapil Sharma1; Anagh Dutta2; Sudipta Patra3; Anish Karmakar1; 1Indian Institute of Technology Roorkee; 2National Institute of Technology, Tiruchirappalli; 3Indian Institute of Technology (BHU)
The present study depicted the synergetic effects of Cu and Ti precipitation on the mechanical response of quenched and tempered (Q&T) steels. Homogenized steel blocks were subjected to quenching (920℃) and tempering at 650℃ for different durations (0.25-1hour) to extract the role of precipitation along with matrix softening in final mechanical response. Extensive studies on the evolution of microstructures and precipitates using electron microscopy along with thermodynamic and kinetic simulation revealed the presence of (Ti, Cr)C and Cu-rich precipitates resulting in the variation of hardness and tensile toughness of the steels. An enriched combination of hardness and tensile toughness i.e. 270 VHN and 14600 MJ/m3 respectively has been observed after the tempering of 0.75 hour. The combined effect of grain refinement along with the severe interaction between nano-sized Cu precipitates and dislocations resulted the superior toughness of the steels. Additionally, the increment of hardness came from Ti-rich carbide precipitates.
Contradicting Role of Martensitic Transformation on Ductility and Toughness in a Medium Mn Steel: C. Hu1; C.P. Huang1; Y.X. Liu1; K. Y. Zhu2; A. Perlade2; MingXin Huang1; 1The University of Hong Kong; Shenzhen Institute of Research and Innovation; 2ArcelorMittal Research, Voie Romaine-BP30320
In this study, the tensile and fracture behaviors of a medium Mn steel fabricated by intercritical annealing (IA) and room-temperature quenching and partitioning (RT-Q&P) were investigated. IA steel consists of recrystallized ferrite and austenite, while RT-Q&P steel has martensite matrix and retained austenite. The austenite in IA steel has higher fraction and is less stable. High-resolution micro-digital image correlation reveals that strain localizes at boundaries in RT-Q&P steel and is concentrated in the austenite of IA steel, resulting in extensive martensitic transformation (MT) and promoting work hardening. However, this excessive transformation leads to decohesion at phase boundaries and premature fracture. The crack-initiation toughness of IA steel is 18% less due to frequent martensite cracking and intergranular decohesion. The hierarchical microstructure in RT-Q&P steel suppresses brittle fracture and enables significant crack tip blunting. The present work demonstrates that the potential trade-off of massive MT is the deterioration of fracture toughness.
J-86: Dissimilar Metal Friction Weld Development for Enhanced Capability for Power Generation Components: Voramon Dheeradhada1; Sharon Huang1; Steve Buresh1; Marissa Brennan1; Patrick Brennan1; Genghis Khan1; Akbar Bagri1; Alireza Namazifard1; Martin Morra1; Tim Stotler2; 1GE Research; 2EWI
Dissimilar metal weld is essential in enabling the use of austenitic steels to join with ferritic steels in boiler as well as heat recovery steam generator (HRSG) operating at high steam temperature. Improvement of durability of dissimilar metal welds will significantly reduced maintenance costs and enhanced capability of plant cyclic operation. This paper focuses on development of rotary friction weld of T91 to 304H to improve joint durability due to reduction in local strain. In addition, friction weld of ferritic steel to nanostructured ferritic alloy (NFA) will be shown. Microstructure of the weld and property evaluation of the weld line will also be discussed. Acknowledgement: This material is based upon work supported by the Department of Energy under Award Number(s) DE-FE0031907.
J-87: Effect of Si on the Liquid Metal Embrittlement Susceptibility of Advanced High Strength Steels: Fateme Abdiyan1; Joseph McDermid1; Hatem Zurob1; 1McMaster University
Advanced high strength steels (AHSS) are excellent choices for automobile industry because of their high specific strength. Resistance spot welding (RSW) is used to join steel sheets; but, melting the protective Zn layer during RSW causes liquid metal embrittlement (LME), manifested in reduced ductility of normally ductile metals. Chemical composition is one of the most important aspects that impacts LME, thus, to develop less susceptible materials, it's important to understand how the susceptibility to LME is affected by the steel composition. Si is one of the essential elements used in the production of AHSS. Si has positive effects on the steel's microstructure and mechanical properties, but high Si concentrations make the steel more susceptible to LME. In this study, hot tensile testing and post-microstructural characterization were used to assess and compare the LME susceptibility of Zn coated AHSSs with various Si levels, to understand the role of Si.
J-88: Effects of Cr on Corrosion Behaviors of Hadfield Steel in a Neutral Aqueous Environment: Sung Jin Kim1; Duck Bin Yun1; Jin Sung Park1; 1Sunchon National University
To expand the industrial applicability of Hadfield steel, its corrosion resistance should be improved. From this perspective, the effects of Cr addition to the steel on the corrosion behaviors were examined using a range of electrochemical measurements. The addition of Cr within a certain amount (approximately 1~2 wt.%) can be effective in decreasing the corrosion kinetics, but addition of more than that can worsen the corrosion resistance. In particular, the decrease in corrosion resistance can be more appreciable in the heat affected zone of the welded steel samples. In this presentation, the change in corrosion behaviors of the steel with respect to Cr contents will be interpreted mechanistically based on the characteristics of the corrosion scale formed on the surface, and the precipitation of M23C6 in the steel matrix. Based on the results, the most desirable alloying strategies of the steel for ensuring the long-term corrosion resistance will be provided.
J-89: Enhancing Tensile Property and Hydrogen Embrittlement Resistance of a Medium Mn Steel by Warm Rolling: Yuxuan Liu1; 1The University of Hong Kong
Warm rolling has recently received more attention in making high-performance steel sheets. In this work, we demonstrate a warm rolled medium Mn steel (WR) compared with one fabricated by intercritical annealing (IA). Instead of low- dislocated and equiaxed grains from intercritical annealing, the WR steel has an elongated prior austenite microstructure with alternating ferrite-rich and -poor regions. Compared with IA steel, the WR steel has higher yield stress attributed to a higher dislocation density and persistent work hardening due to continuous TRIP effect. After hydrogen charging, both steels are degraded by hydrogen-assisted cracks because of the HEDE mechanism. Multiple crack initiations are observed in both steels, which are primarily perpendicular to the loading direction in the IA steel while deflected by PAGB and ferrite/martensite boundaries in ferrite-rich regions in the WR steel. The crack deflections contribute to the improved hydrogen embrittlement resistance of the WR steel.
J-90: High-speed Deformation Behavior of a Heterogeneous-nano Structured Austenitic Stainless Steel: Chihiro Watanabe1; Ayumu Terada1; Norimitsu Koga2; Tomotsugu Shimokawa1; Masakazu Kobayashi3; Hiromi Miura3; 1Kanazawa University; 2Kanazawa Univeristy; 3Toyohashi University of Technology
High-speed deformation behavior of SUS316LN stainless steel with the heterogeneous-nano (HN) structure, composed of deformation twin domains, ultrafine lamellae and shear bands, was systematically investigated by means of Charpy impact tests at some temperatures and dynamic tensile tests at room temperature (RT). The HN structured SUS316LN exhibited an excellent balance of strength and Charpy impact value at RT. At a lower impact speed v, the impact value increased with lowering test temperature from RT to 173 K. Nevertheless at a higher v, the impact value was lower than that at the lower v and became approximately identical irrespective of temperature. During the impact tests, deformation-induced γ → α’ martensitic transformation was taken place. The volume fraction of the α’ phase denoted the same tendency of the impact value. These results strongly suggest that the deformation-induced martensitic transformation plays an important role in the impact value.
J-91: Low-temperature Impact Properties of X70 Line Pipe Steel Depending on Location and Orientation: Seoyoon Gong1; Jeongho Han2; Se-Eun Shin1; Jihan Gwak1; 1Sunchon National University; 2Hanyang University
Due to the continuous use of oil and gas resources, mining in extreme environments is increasing due to a decrease in resource reserves in areas with a good mining environment, and accordingly, the low-temperature properties of line pipe steels are important. In this study, the impact properties by Charpy impact testing at various low-temperatures and microstructure of X70 steels were analyzed depending on the location and orientation of hot-rolled specimens. The fracture toughness was measured by Charpy impact testing at –45 °C depending on the location and orientation (transverse & rolling direction). The microstructure shows the two-phase of degenerate pearlite and acicular/quasi-polygonal ferrite. As the result, the impact energy was 54.16 J from the outside and 115.21 J from the center, in the width direction, and it increased toward the center. It is considered that this is because the fraction of degenerate pearlite decreases toward the center.
J-92: Microstructural Characterization of EUROFER97/3-type Steels Before Neutron Irradiation: Michael Thomas Duerrschnabel1; Ute Jäntsch1; Michael Rieth1; 1Karlsruhe Institute of Technology
Recent geopolitical events and the ongoing climate change demand for improved high-performance materials in energy technology, for example in future fusion reactors. 9%Cr reduced activation ferrite-martensitic steels like EUROFER are the material of choice, since it can withstand temperatures of 550°C as well as neutron doses larger than 20 dpa while still providing acceptable mechanical properties. The current study will summarize the results of a detailed microstructural characterization of several EUROFER97/3-type alloys by electron microscopy with mechanical properties and thermodynamic calculations. The single alloys slightly differ in their composition. In detail, the study will reveal the lath sizes by electron backscatter diffraction (EBSD). Furthermore, nanoscale transmission electron microscopy (TEM) measurements will reveal the number density, structure, and chemistry of nanosized precipitates. The microstructural data in combination will be related with the mechanical test results and with the thermodynamic simulation, which will provide a substantial basis for ongoing neutron irradiation studies.
Cancelled
Microstructural Evolution and Mechanical Properties of Zinc Coated Press Hardened Steels with Increased Carbon Content: Sara Kheiri1; Joseph McDermid1; Mike Bruhis1; 1McMaster University
Press-hardened steels (PHS) are comprising increasing proportions of automotive body-in-white (BIW) for passenger safety applications while allowing for significant BIW mass reductions, which in turn reduce vehicle emissions. Zn coatings can be a promising alternative to the traditional Al-Si coatings for 22MnB5 family of alloys as they can provide better corrosion protection at a lower cost despite the challenge of Liquid Metal Embrittlement (LME). It has been shown that LME can successfully be avoided by using prototype 2% Mn PHS grade while meeting the target UTS of 1500 MPa. The objective of this study was to propose a substrate with higher carbon content that both avoids LME and exhibits superior mechanical properties. Thus, the C content of a PHS grade with the composition of 0.20C-2.01Mn-0.26Si-0.005Ti-0.01B (wt%) was increased by carburizing. This paper will present the microstructural development and mechanical properties as a function of processing window and substrate C content.
Cancelled
Microstructure and Mechanical Properties of Rolled Homogenized Armor Steel during Linear Friction Welding Under Different Loads: Kanwal Chadha1; 1University of New Brunswick
The work is focused on the microstructural and mechanical characterization of linear friction welded rolled homogenized armor (RHA) steel subjected to different load conditions. RHA steel is extensively used for ballistic impact resistance of armored vehicles. To study the effect, RHA steels were subjected to different set of loads namely 200 KN and 100 KN. Microstructural analysis was conducted using electron backscattered diffraction technique. The samples were subjected to tensile testing in order to examine the strength of the joint. It was found that the average grain size at the center of the weld reduced with the reduction in load. The fractography results showed that the fracture occurred with ductile fracture. Interestingly, none of the samples broke from the weld joint which shows the strength in the weld is higher than that of the sample.