A5089202483- Microstructure and Mechanical Properties of Steels
- Metal Alloys Wear and Properties
- Hydrogen embrittlement and corrosion behaviors in metals
- Metallurgy and Material Forming
- Microstructure and mechanical properties
- Welding Techniques and Residual Stresses
- Magnetic Properties and Applications
- High Temperature Alloys and Creep
- Metal Forming Simulation Techniques
- Fatigue and fracture mechanics
- Metal and Thin Film Mechanics
- Advanced materials and composites
- Corrosion Behavior and Inhibition
- Material Properties and Failure Mechanisms
- Metallurgical Processes and Thermodynamics
- Intermetallics and Advanced Alloy Properties
- Non-Destructive Testing Techniques
- Erosion and Abrasive Machining
- Advanced Surface Polishing Techniques
- Surface Treatment and Residual Stress
- Additive Manufacturing Materials and Processes
- Structural Load-Bearing Analysis
- Laser and Thermal Forming Techniques
- Mechanical stress and fatigue analysis
- High Entropy Alloys Studies
University of Oulu
2005-2025
Svenskt Stål (Finland)
2025
University of Miskolc
2025
Central Metallurgical Research and Development Institute
2019-2025
Finnish Society of Sciences and Letters
2022
Linde (Germany)
2013
AGA (Sweden)
2013
Schweißtechnische Lehr- und Versuchsanstalt
2011
Offshore steels are designed for high strength and toughness to endure extreme offshore marine conditions. Welding thick steel sections often requires multiple passes, affecting the microstructures of previous passes due thermal cycles. These heat-affected zones (HAZ) in weld metal less studied than those base metal. Real welding HAZs narrow challenging study. Physical simulation can create various on a larger scale microstructural mechanical characterization, allowing easy study different...
Metastable austenite significantly impacts the mechanical properties of Advanced High-Strength Steels (AHSS), especially Medium Mn Steel (MMnS), where its formation rate during intercritical annealing depends strongly on initial microstructure. This study employs thermodynamic and diffusion-controlled simulations to investigate two distinct morphologies retained austenite–lamellar blocky known also as globular– commonly observed in an intercritically annealed hot-rolled MMnS. Utilizing...
Medium manganese steels (MMnS) are known as third-generation high-strength steels, providing an excellent balance of high strength and ductility at a lower cost than second-generation steels. However, the increasing demand for with improved hydrogen embrittlement resistance highlights need effective development new alloys. This study explores computational design MMnS better combination strength, ductility, resistance. Mechanical properties vary due to changes in chemical composition...
Quality assurance is one of the largest challenges to widespread adoption metal additive manufacturing technology. Deposition pattern can significantly impact temperature distribution during process and thus overall quality residual stress formation manufactured components. In order explore intricate relationship, three different deposition patterns in DED-Arc manufacturing, meander pattern, spiral newly developed S were experimentally numerically scrutinized terms resulting distribution,...
The novel processing concept of direct quenching and partitioning (DQ&P) has been explored with a medium-carbon (0.4 wt.% C) steel to evaluate optimize the route for excellent property combinations. New compositional design approach was based on physical simulation studies aiming understand influence varying silicon contents (1.5, 0.75 0.25 wt.%) Q&P parameters microstructural development including carbide formation retained austenite stabilization. Optimized were selected DQ&P laboratory...
Quenching and partitioning (Q&P) treated steels are traditionally alloyed with silicon (Si), but its precise role on microstructural mechanisms occurring during is not thoroughly understood. In this study, dilatometric analysis has been combined detailed characterization to unravel the competing either in parallel or succession. Three 0.4 wt.% carbon varying Si contents were quenched 150 °C for ~20% untransformed austenite, partitioned 10–1000 s temperature range 200–300 °C. The steel low...
The extremely altered topmost surface layer, known as the white formed in a medium-carbon low-alloy steel result of impacts by angular 10–12 mm granite particles during slurry erosion process is comprehensively investigated. For this purpose, characteristics, morphology, and formation mechanism layer are described based on microstructural observations using optical, scanning transmission electron microscopies well nanoindentation hardness measurements modelling deformation. exhibits...
Suppressing hydrogen embrittlement in martensitic steels is a longstanding challenge. Here, we studied the effects of prior austenite grain (PAG) shape and size with 0.25C steel utilising novel situ H-charging, constant-displacement Tuning-fork testing (TFT) H-permeation tests. Anisotropic elongated PAG structure has enhanced HE resistance transverse to rolling direction (RD) slower crack propagation rate (CPR) quasi-cleavage fracture. Larger grains are prone intergranular fracture when...
In the present study, hydrogen embrittlement (HE) susceptibility of an additively manufactured (AM) 316L stainless steel (SS) was investigated. The materials were fabricated in form a lattice auxetic structure with three different strut thicknesses, 0.6, 1, and 1.4 mm, by laser powder bed fusion technique at volumetric energy 70 J·mm-3. effect H charging on strength ductility structures evaluated conducting tensile testing H-charged specimens slow strain rate 4 × 10-5 s-1. Hydrogen...
Advanced (ultra)high-strength steels that utilise bcc-fcc microstructures are appealing solutions for producing a combination of high strength and deformability. However, they also susceptible to hydrogen embrittlement (HE). As larger less stable retained austenite (RA) can impair mechanical performance, its size morphology critical factors achieving maintaining the desired properties. Here, we present combined experimental–density functional theory (DFT) study on HE with medium-carbon...
The influence of cooling rate on the microstructure and mechanical properties two new ultrahigh-strength steels (UHSSs) with different levels C, Cr Ni has been evaluated for as-cooled untempered condition. One UHSS had higher contents C Cr, while other one a content. On basis dilatation curves, microstructures, macrohardness microhardness, continuous transformation diagrams were constructed as guide to heat treatment possibilities. Cooling rates (CRs) 60, 1 0.01 °C/s selected more detailed...
In this paper, the effects of different tempering temperatures on a recently developed ultrahigh-strength steel with 0.4 wt.% carbon content were studied. The is designed to be used in press-hardening for wear applications, which require high surface hardness (650 HV/58 HRC). Hot-rolled sheet from hot strip mill was austenitized, water quenched and subjected 2-h at ranging 150 °C 400 °C. Mechanical properties, microstructure, dislocation densities, fracture surfaces steels characterized....
Experimental steels, a direct-quenched and partitioned (DQP) steel carbide-free bainitic (CFB), were tested along with commercial martensitic 500 HB grade wear resistant in high-stress abrasive conditions. The three steels had different microstructures consisting of varying fractions morphologies martensite, retained austenite, ferrite. results showed that the CFB lower mass loss compared to similar hardness level. DQP higher initial outperformed other two steels. Wear surface...
A low-alloyed ultrahigh-strength steel comprising CrNiMoWMnV was designed based on thermodynamic calculations and by controlling the microalloying elements to promote various strengthening mechanisms upon processing. The hot deformation behaviour mechanism were correlated with processing parameters, that is, strain rate temperature. fine features of deformed microstructures analysed using electron backscatter diffraction (EBSD) MATLAB software, combined MTEX texture crystallographic analysis...
Rapid tempering is a remarkable sustainable and energy-efficient way to modify properties of as-quenched martensite, particularly its toughness ductility. In this work, tensile fracture properties, microstructural evolution medium-carbon (0.4 wt%), low-alloy steel under different rapid circumstances are discussed. The hot-rolled direct-quenched specimens were subjected treatments (heating rate about 90 °C/s) the temperatures (320–720 °C). As reference material, one sample was conventional at...