scholarly journals Influence of Hot Plastic Deformation in γ and (γ + α) Area on the Structure and Mechanical Properties of High-Strength Low-Alloy (HSLA) Steel

Materials ◽  
2016 ◽  
Vol 9 (12) ◽  
pp. 971 ◽  
Author(s):  
Jan Sas ◽  
Tibor Kvačkaj ◽  
Ondrej Milkovič ◽  
Michal Zemko
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Hsla Steel ◽  
High Strength ◽  
Hot Plastic Deformation

scholarly journals Overview of HSS Steel Grades Development and Study of Reheating Condition Effects on Austenite Grain Size Changes

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1988
Author(s):  
Tibor Kvackaj ◽  
Jana Bidulská ◽  
Róbert Bidulský
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
High Strength Steel ◽  
Single Phase ◽  
Hsla Steel ◽  
High Strength ◽  
Strength Properties ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Steel Grades

This review paper concerns the development of the chemical compositions and controlled processes of rolling and cooling steels to increase their mechanical properties and reduce weight and production costs. The paper analyzes the basic differences among high-strength steel (HSS), advanced high-strength steel (AHSS) and ultra-high-strength steel (UHSS) depending on differences in their final microstructural components, chemical composition, alloying elements and strengthening contributions to determine strength and mechanical properties. HSS is characterized by a final single-phase structure with reduced perlite content, while AHSS has a final structure of two-phase to multiphase. UHSS is characterized by a single-phase or multiphase structure. The yield strength of the steels have the following value intervals: HSS, 180–550 MPa; AHSS, 260–900 MPa; UHSS, 600–960 MPa. In addition to strength properties, the ductility of these steel grades is also an important parameter. AHSS steel has the best ductility, followed by HSS and UHSS. Within the HSS steel group, high-strength low-alloy (HSLA) steel represents a special subgroup characterized by the use of microalloying elements for special strength and plastic properties. An important parameter determining the strength properties of these steels is the grain-size diameter of the final structure, which depends on the processing conditions of the previous austenitic structure. The influence of reheating temperatures (TReh) and the holding time at the reheating temperature (tReh) of C–Mn–Nb–V HSLA steel was investigated in detail. Mathematical equations describing changes in the diameter of austenite grain size (dγ), depending on reheating temperature and holding time, were derived by the authors. The coordinates of the point where normal grain growth turned abnormal was determined. These coordinates for testing steel are the reheating conditions TReh = 1060 °C, tReh = 1800 s at the diameter of austenite grain size dγ = 100 μm.

Microstructure Evolution and Deformation Mechanisms of Harmonic Structure Designed Materials

2016 ◽  
Vol 879 ◽  
pp. 145-150
Author(s):  
Kei Ameyama ◽  
Sanjay Kumar Vajpai ◽  
Mie Ota
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Powder Metallurgy ◽  
Early Stage ◽  
High Strength ◽  
Plastic Instability ◽  
Structure Design ◽  
Harmonic Structure ◽  
Homogeneous Microstructure ◽  
Macro Scale

This paper presents the novel microstructure design, called Harmonic Structure, which gives structural metallic materials outstanding mechanical properties through an innovative powder metallurgy process. Homogeneous and ultra-fine grain (UFG) structure enables the materials high strength. However, such a “Homo-“ and “UFG” microstructure does not, usually, satisfy the need to be both strong and ductile, due to the plastic instability in the early stage of the deformation. As opposed to such a “Homo-and UFG“ microstructure, “Harmonic Structure” has a heterogeneous microstructure consisting of bimodal grain size together with a controlled and specific topological distribution of fine and coarse grains. In other words, the harmonic structure is heterogeneous on micro-but homogeneous on macro-scales. In the present work, the harmonic structure design has been applied to pure metals and alloys via a powder metallurgy route consisting of controlled severe plastic deformation of the corresponding powders by mechanical milling or high pressure gas milling, and subsequent consolidation by SPS. At a macro-scale, the harmonic structure materials exhibited superior combination of strength and ductility as compared to their homogeneous microstructure counterparts. This behavior was essentially related to the ability of the harmonic structure to promote the uniform distribution of strain during plastic deformation, leading to improved mechanical properties by avoiding or delaying localized plastic instability.

Paradox of Strength and Ductility in Metals Processed Bysevere Plastic Deformation

2002 ◽  
Vol 17 (1) ◽  
pp. 5-8 ◽  
Author(s):  
R. Z. Valiev ◽  
I. V. Alexandrov ◽  
Y. T. Zhu ◽  
T. C. Lowe
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Yield Strength ◽  
Mechanical Behavior ◽  
High Strength ◽  
High Ductility ◽  
Elongation To Failure ◽  
Failure Ductility ◽  
Strength And Ductility

It is well known that plastic deformation induced by conventional forming methodssuch as rolling, drawing or extrusion can significantly increase the strength of metalsHowever, this increase is usually accompanied by a loss of ductility. For example, Fig.1 shows that with increasing plastic deformation, the yield strength of Cu and Almonotonically increases while their elongation to failure (ductility) decreases. Thesame trend is also true for other metals and alloys. Here we report an extraordinarycombination of high strength and high ductility produced in metals subject to severeplastic deformation (SPD). We believe that this unusual mechanical behavior is causedby the unique nanostructures generated by SPD processing. The combination ofultrafine grain size and high-density dislocations appears to enable deformation by newmechanisms. This work demonstrates the possibility of tailoring the microstructures ofmetals and alloys by SPD to obtain both high strength and high ductility. Materialswith such desirable mechanical properties are very attractive for advanced structuralapplications.

Effect of Microalloying Elements on Mechanical Properties in the High Strength Low Alloy Steel

2015 ◽  
Vol 830-831 ◽  
pp. 231-233 ◽  
Author(s):  
P.K. Mandal ◽  
Ravi Kant
Keyword(s):  
Mechanical Properties ◽  
Hsla Steel ◽  
High Strength ◽  
Microstructural Characterization ◽  
Strengthening Mechanism ◽  
Treatment Processes ◽  
Heating Treatment ◽  
Secondary Precipitates ◽  
Microalloying Elements

The effect of microalloying elements in Ti-Nb-V containing high strength low alloy (HSLA) steel has been investigated in the present study. The addition of low alloying elements (such as Ti, Nb and V) and distinct heating treatment processes has been used to improve the mechanical properties of HSLA steel. The effect on the microstructure and mechanical properties of normalizing treatment (at 950°C) of as forged steel has been investigated. The microstructural characterization of microalloyed HSLA steel is carried out by using different techniques such as optical microscopy, scanning electron microscopy (SEM) etc. The hardness, tensile testing and Charpy V notch impact tests are performed to study the mechanical behaviour of the alloy. It has been concluded that the precipitation strengthening mechanism for the improvement of impact toughness due to secondary precipitates such as TiN, Ti(C, N), VN etc.

Mechanical Properties of High-Manganese Austenitic TWIP-Type Steel

2014 ◽  
Vol 783-786 ◽  
pp. 27-32 ◽  
Author(s):  
Leszek Adam Dobrzański ◽  
Wojciech Borek ◽  
Janusz Mazurkiewicz
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
High Strength ◽  
Deformation Energy ◽  
Mechanical Twinning ◽  
Austenitic Steels ◽  
Manganese Steel ◽  
Cold Plastic Deformation ◽  
High Plasticity ◽  
High Manganese

Taking into consideration increased quantity of accessories used in modern cars, decreasing car’s weight can be achieved solely by optimization of sections of sheets used for bearing and reinforcing elements as well as for body panelling parts of a car. Application of sheets with lower thickness requires using sheets with higher mechanical properties, however keeping adequate formability. The goal of structural elements such as frontal frame side members, bumpers and the others is to take over the energy of an impact. Therefore, steels that are used for these parts should be characterized by high value of UTS and UEl, proving the ability of energy absorption. Among the wide variety of recently developed steels, high-manganese austenitic steels with low stacking faulty energy are particularly promising, especially when mechanical twinning occurs. Beneficial combination of high strength and ductile properties of these steels depends on structural processes taking place during cold plastic deformation, which are a derivative of SFE of austenite, dependent, in turn on the chemical composition of steel and deformation temperature. High-manganese austenitic steels in effect of application of proper heat treatment or thermo-mechanical treatment can be characterized by different structure assuring the advantageous connection of strength and plasticity properties. Proper determinant of these properties can be plastic deformation energy supply determined by integral over surface of cold plastic deformation curve. Obtaining of high strength properties with retaining the high plasticity has significant influence for the development of high-manganese steel groups and their significance for the development of materials engineering.

Influence of Severe Plastic Deformation on Mechanical Properties of an AA5024 Alloy

2016 ◽  
Vol 879 ◽  
pp. 1317-1322 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Yuzbekova ◽  
Tatiana Lebedkina ◽  
Mikhail Lebyodkin ◽  
Rustam Kaibyshev
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Strength ◽  
Coarse Grained ◽  
Type B ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Elongation To Failure ◽  
Dislocation Strengthening

The paper reports on the effect of severe plastic deformation on mechanical properties of an Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (in wt. pct.) alloy processed by equal channel angular pressing followed by cold rolling (CR). The sheets of the 5024 alloy with coarse grained (CG) structure exhibited a yield stress (YS) near 410 MPa and an ultimate tensile strength (UTS) of 480 MPa, while the YS and UTS of this material with ultrafine-grained (UFG) structure increased to 530 and 560 MPa, respectively. On the other hand, the elongation to failure decreased by a factor of 2 and 4 after CR and CR following ECAP, respectively. It was shown that dislocation strengthening attributed to extensive CR plays a major role in achieving high strength of this alloy. Besides these macroscopic characteristics, jerky flow caused by the Portevin-Le Chatelier (PLC) instability of plastic deformation was examined. The formation of UFG structure results in a transition from mixed type A+B to pure type B PLC serrations. No such effect on the serrations type was observed after CR.

scholarly journals INVESTIGATION OF HOT PLASTIC DEFORMATION OF LABORATORY AXIAL FLOATS

2021 ◽  
pp. 12-16
Author(s):  
Oleksandr Babachenko ◽  
Ganna Kononenko ◽  
Katerina Domina ◽  
Rostislav Podolskyi ◽  
Olena Safronova
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Chemical Composition ◽  
Physical And Mechanical Properties ◽  
Pressure Treatment ◽  
Initial Length ◽  
Hot Plastic Deformation ◽  
The Impact ◽  
Further Development

A review of research in the field of modeling experiments on heat treatment and pressure treatment of metal and the impact on the physical and mechanical properties of steel with a chemical composition of 0.59% C, 0.31% Si, 0.73% Mn. A mathematical model for calculating the physical and mechanical properties of steel in the process of hot plastic deformation has been developed and prospects for further development of research in this area have been identified. As a result of modeling, the following functions were obtained: the amount of deformation in the direction of the applied force divided by the initial length of the material. The coefficient of elongation of the material with the actual chemical composition at a temperature of 1250 ± 10 ° C, which was 0.32. When comparing the values of the load that was applied to the GPA in the laboratory and the results of calculations using the developed model, it was found that they have close values of about 45 MPa. This confirms the adequacy of the obtained model.A review of research in the field of modeling experiments on heat treatment and pressure treatment of metal and the impact on the physical and mechanical properties of steel with a chemical composition of 0.59% C, 0.31% Si, 0.73% Mn. A mathematical model for calculating the physical and mechanical properties of steel in the process of hot plastic deformation has been developed and prospects for further development of research in this area have been identified. As a result of modeling, the following functions were obtained: the amount of deformation in the direction of the applied force divided by the initial length of the material. The coefficient of elongation of the material with the actual chemical composition at a temperature of 1250 ± 10 ° C, which was 0.32. When comparing the values of the load that was applied to the GPA in the laboratory and the results of calculations using the developed model, it was found that they have close values of about 45 MPa. This confirms the adequacy of the obtained model.

Compressive and Shearing Mechanical Anisotropy of Aluminum after ECAP

2014 ◽  
Vol 1016 ◽  
pp. 100-104
Author(s):  
Cleber Granato de Faria ◽  
Tércio Assunção Pedrosa ◽  
Roberto Braga Figueiredo ◽  
Maria Teresa Paulino Aguilar ◽  
Paulo Roberto Cetlin
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Cross Section ◽  
High Strain ◽  
High Strength ◽  
The Other ◽  
Mechanical Anisotropy ◽  
Single Plane ◽  
Angular Pressing ◽  
Very High

Severe plastic deformation (SPD), where metals are deformed up to very high strain values, leads to a very small grain size and a high strength of the material. ECAP (Equal Channel Angular Pressing) is one of the SPD methods, and involves the extrusion of a metal billet through two intersecting channels with identical cross-section and forming an angle between them. The material undergoes shearing as it crosses from one channel to the other, but its external dimensions are not altered. Shearing occurs along a single plane, which may lead to anisotropy in the mechanical properties of the material after ECAP. Compression, tension and shearing tests along various directions in the as-processed specimens indicated the presence of mechanical anisotropy in ECAP processed aluminum.

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