Effect of hydrogen charging on the mechanical properties of advanced high strength steels

2014 ◽  
Vol 39 (9) ◽  
pp. 4647-4656 ◽  
Author(s):  
T. Depover ◽  
D. Pérez Escobar ◽  
E. Wallaert ◽  
Z. Zermout ◽  
K. Verbeken
Keyword(s):  
Mechanical Properties ◽  
High Strength Steels ◽  
High Strength ◽  
Hydrogen Charging ◽  
Advanced High Strength Steels

Relationship between Microstructure and Mechanical Properties in Q&P-Steels

2016 ◽  
Vol 879 ◽  
pp. 1933-1938 ◽  
Author(s):  
Richard G. Thiessen ◽  
Georg Paul ◽  
Roland Sebald
Keyword(s):  
Mechanical Properties ◽  
Dual Phase Steel ◽  
High Strength Steels ◽  
High Strength ◽  
The Body ◽  
Advanced High Strength Steels ◽  
Passenger Safety ◽  
Back Scattering ◽  
Body In White ◽  
Expected Increase

Third-Generation advanced high strength steels are being developed with the goal of reducing the body-in-white weight while simultaneously increasing passenger safety. This requires not only the expected increase in strength and elongation, but also improved local formability. Optimizing elongation and formability were often contradictory goals in dual-phase steel developments. Recent results have shown that so-called "quench and partitioning" (Q&P) concepts can satisfy both requirements [1]. Many Q&P-concepts have been studied at thyssenkrupp Steel Europe. Thorough investigation of the microstructure has revealed relationships between features such as the amount, morphology and chemical stability of the retained austenite and the obtained mechanical properties. An evaluation of the lattice strain by means of electron-back-scattering-diffraction has also yielded a correlation to the obtained formability. The aim of this work is to present the interconnection between these microstructural features and propose hypotheses for the explanation of how these features influence the macroscopically observed properties.

scholarly journals Microstructural characterization and mechanical properties of spot welded dissimilar advanced high strength steels

2021 ◽  
Author(s):  
Muhammad Sohaib Khan
Keyword(s):  
Mechanical Properties ◽  
High Strength Steels ◽  
High Strength ◽  
Microstructural Characterization ◽  
Advanced High Strength Steels ◽  
Spot Welded

Microstructural characterization and mechanical properties of spot welded dissimilar advanced high strength steels

Fatigue Performance of Laser Brazes in Advanced High Strength Steels

2010 ◽  
Vol 638-642 ◽  
pp. 3254-3259 ◽  
Author(s):  
M.H.E. Janssen ◽  
M.J.M. Hermans ◽  
M. Janssen ◽  
I.M. Richardson
Keyword(s):  
Mechanical Properties ◽  
Trip Steel ◽  
Uniform Elongation ◽  
High Strength Steels ◽  
High Strength ◽  
Process Conditions ◽  
Trip Steels ◽  
Advanced High Strength Steels ◽  
Brazed Joints ◽  
Welding Processes

Advance high strength steels (AHSS), like dual phase (DP) and transformation induced plasticity (TRIP) steels, offer high strength and toughness combined with excellent uniform elongation. However, the higher alloying content of these steels limit their weldability and the thermal cycle of welding processes destroys the carefully designed microstructure. This will result in inferior mechanical properties of the joint. Therefore, joining processes with a low heat input, like brazing, are recommendable. Data regarding mechanical properties of joints in DP and TRIP steel is limited, especially for brazed joints. Results with respect to the fatigue lifetime of laser brazed butt joints are presented. In DP and TRIP steel, crack initiation takes place at the braze toe. In DP steel the crack propagates through the base metal. In TRIP steel, however, the crack may either follow the interface or may continue through the steel depending on the maximum stress level. The different failure mechanisms are explained on the basis of process conditions, the microstructure and the stress state.

scholarly journals Effect of Quenching and Partitioning Heat Treatment on the Fatigue Behavior of 42SiCr Steel

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1699
Author(s):  
Marco Thomä ◽  
Guntram Wagner
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Material Properties ◽  
Retained Austenite ◽  
Fatigue Behavior ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced High Strength Steels ◽  
Scanning Electron

The manufacturing of advanced high-strength steels with enhanced ductility is a persistent aim of research. The ability of a material to absorb high loads while showing a high deformation behavior is a major task for many industrial fields like the mobility sector. Therefore, the material properties of advanced high-strength steels are one of the most important impact factors on the resulting cyclic fatigue behavior. To adjust advanced material properties, resulting in high tensile strengths as well as an enhanced ductility, the heat treatment process of quenching and partitioning (QP) was developed. The quenching takes place in a field between martensite start and martensite finish temperature and the subsequent partitioning is executed at slightly elevated temperatures. Regarding the sparsely investigated field of fatigue research on quenched and partitioned steels, the present work investigates the influence of a QP heat treatment on the resulting microstructure by light and scanning electron microscopy as well as on the mechanical properties such as tensile strength and resistance against fatigue regarding two different heat treatment conditions (QP1, QP2) in comparison to the cold-rolled base material of 42SiCr steel. Therefore, the microscopic analysis proved the presence of a characteristic quenched and partitioned microstructure consisting of a martensitic matrix and partial areas of retained austenite, whereas carbides were also present. Differences in the amount of retained austenite could be observed by using X-ray diffraction (XRD) for the different QP routes, which influence the mechanical properties resulting in higher tensile strength of about 2000 MPa for QP1 compared to about 1600 MPa for QP2. Furthermore, the transition for the fatigue limit was approximated by using stepwise load increase tests (LIT) and afterwards verified by constant amplitude tests (CAT) in accordance with the staircase method, whereas the QP 1 condition reached the highest fatigue strength of 900 MPa. Subsequent light and scanning electron microscopy of selected fractured surfaces and runouts showed a different behavior regarding the size of the fatigue fracture area and also differences in the microstructure of these runouts.

Mechanical properties and microstructure of low carbon ultra-high strength steels (UHSS) microalloyed with boron

2012 ◽  
Vol 1373 ◽  
Author(s):  
I. Mejía ◽  
A. García de la Rosa ◽  
A. Bedolla-Jacuinde ◽  
J.M. Cabrera
Keyword(s):  
Mechanical Properties ◽  
Research Work ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Low Carbon ◽  
Advanced High Strength Steels ◽  
New Family ◽  
Ultra High Strength Steels ◽  
Hot Rolled

ABSTRACTThe aim of this research work is to study the effect of boron addition on mechanical properties and microstructure of a new family of low carbon NiCrVCu advanced high strength steels (AHSS). Experimental steels are thermo-mechanically processed (TMP) (hot-rolled+quenched). Results show that the microstructure of these steels contains bainite and martensite, predominantly, which nucleate along prior austenite grain boundaries (GB). On the other hand, tensile tests reveal that the TMP steels have YS (0.2% offset) of 978 MPa, UTS of 1140 MPa and EL of 18%. On the basis of exhibited microstructure and mechanical properties, these experimental steels are classified as bainitic-martensitic complex phase (CP) advanced ultra-high strength steels (UHSS).

scholarly journals Temperature Dependence of the Static and Dynamic Behaviour in a Quenching and Partitioning Processed Low-Si Steel

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 509 ◽  
Author(s):  
Florian Vercruysse ◽  
Carola Celada-Casero ◽  
Bernd M. Linke ◽  
Patricia Verleysen ◽  
Roumen H. Petrov
Keyword(s):  
Mechanical Properties ◽  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Trip Effect ◽  
Quenching And Partitioning ◽  
Advanced High Strength Steels ◽  
Wide Range

Because of their excellent combination of strength and ductility, quenching and partitioning (Q & P) steels have a great chance of being added to the third generation of advanced high strength steels. The large ductility of Q & P steels arises from the presence of 10% to 15% of retained austenite which postpones necking due to the transformation induced plasticity (TRIP) effect. Moreover, Q & P steels show promising forming properties with favourable Lankford coefficients, while their planar anisotropy is low due to a weak texture. The stability of the metastable austenite is the key to obtain tailored properties for these steels. To become part of the newest generation of advanced high strength steels, Q & P steels have to preserve their mechanical properties at dynamic strain rates and over a wide range of temperatures. Therefore, in the present study, a low-Si Q & P steel was tested at temperatures from −40 °C to 80 °C and strain rates from 0.001 s−1 to 500 s−1. Results show that the mechanical properties are well-preserved at the lowest temperatures. Indeed, at −40 °C and room temperature, no significant loss of the deformation capacity is observed even at dynamic strain rates. This is attributed to the presence of a large fraction of austenite that is so (thermally) stable that it does not transform in the absence of deformation. In addition, the high stability of the austenite decreases the elongation at high test temperatures (80 °C). The additional adiabatic heating in the dynamic tests causes the largest reduction of the uniform strain for the samples tested at 80 °C. Quantification of the retained austenite fraction in the samples after testing confirmed that, at the highest temperature and strain rate, the TRIP effect is suppressed.

scholarly journals The Effect of Alloying on Mechanical Properties of Advanced High Strength Steels

2014 ◽  
Vol 59 (3) ◽  
pp. 1189-1192 ◽  
Author(s):  
L. Kučerová ◽  
H. Jirková ◽  
B. Mašek
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Cooling Rate ◽  
High Strength Steels ◽  
High Strength ◽  
Microstructure Development ◽  
Quenching And Partitioning ◽  
Advanced High Strength Steels ◽  
Quenching And Partitioning Process ◽  
Effect Of Alloying

Abstract Quenching and partitioning process with incorporated incremental deformation was optimized for six high strength steels with various contents of carbon (0.4-0.6%), manganese (0.6-1.2), silicon (2-2.6%) and chromium (0.8-1.3%). The optimization was gradually done for each steel with respect to the final microstructures and properties. The effect of cooling rate, quenching and partitioning temperature on microstructure development was further investigated. Interesting combinations of mechanical properties were obtained, with tensile strength in the region of 1600-2400 MPa and ductility of 6-20%.

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