Microstructure and Mechanical Properties of Nb Alloyed Steel Processed by Hot Equal Channel Angular Extrusion

2016 ◽  
Vol 879 ◽  
pp. 2528-2531
Author(s):  
Akira Yanagida ◽  
Ryo Aoki ◽  
Masataka Kobayashi

A Nb alloyed low carbon steel was processed by hot equal channel angular extrusion (ECAE) and following transformation. The workpieces were heated up to the 960°C in the furnace for 10 min within the container block. Before extrusion, the die was preheated to 400oC. The workpiece was cooled in the die after ECAE process. 1 pass and 2 pass via route C were conducted at a speed of 32mm/s, the inter-pass time is about 2 sec. The sample of average ferrite grain size of about 2μm, a tensile strength of 800MPa, a total elongation about 20% is produced after 2 pass ECAE processed and subsequent cooling.

2020 ◽  
Vol 835 ◽  
pp. 141-148
Author(s):  
Hassan Bahaa-Eldin ◽  
Mamdouh Eissa ◽  
Ahmed Al-Sheikh ◽  
Mohamed Kamal El-Fawkhry ◽  
Taha Mattar

Reduction in grain size of bcc based structure steel is still highly concerned in the cold rolled sheet to attain superior mechanical properties. As long as, the reduction of weight is much considered in the structure purposes, the strength/weight ratio of steel is highly demanded. In this study, an innovative technique was applied to attain ferrite grain size with hundreds of nanometer, in tandem with preserving the mechanical properties. In this approach, the micro-alloyed low carbon steel resulted from the thermomechanical process was followed by subcritical annealing regime prior to the first critical transformation temperature. To identify the effect of a micro-alloying element as vanadium, and the effect of subcritical annealing regime on the low carbon steel, two low carbon steel was subjected to studying in this research. The results refer that applying a subcritical annealing regime for the micro-alloyed low carbon steel after hot compression at intercritical annealing temperature can lead for attaining hundreds of nanometer ferrite grain size, which has a powerful effect on promoting the strength of the steel to exceed 1200 Mpa, in one hand with preserving the formability up to 20% as uniform elongation. Unexpectedly, the fine grain size obtained after the innovative technique promotes the impact toughness at room temperature, which is attributed to the fineness and the spheroid morphology of the secondary phase in conjugation with bcc ferrite structure.


2014 ◽  
Vol 1082 ◽  
pp. 202-207 ◽  
Author(s):  
Shu Yan ◽  
Xiang Hua Liu

A low carbon steel was treated by quenching and partitioning (Q&P) process, and a detailed characterization of the microstructural evolution and testing of mechanical properties were carried out. The resulted mechanical properties indicate that with the partitioning time increasing, the tensile strength decreases rapidly first and then remains stable, and the total elongation increases first then decreases. The investigated steel subjected to Q&P process exhibits excellent products of strength and elongation (17.8-20.6 GPa•%). The microstructural evolution of martensite matrix during the partitioning step was observed, and the morphology and content of retained austenite were characterized. The working hardening behavior of the samples was analyzed, and the retained austenite with higher carbon content contributes to the uniform elongation more effectively.


2016 ◽  
Vol 705 ◽  
pp. 250-254 ◽  
Author(s):  
Yustiasih Purwaningrum ◽  
Triyono ◽  
M. Wirawan Pu ◽  
Fandi Alfarizi

The aimed of this research is to determine the feasibility and effect of the mixture of the shielding gas in the physical and mechanical properties. Low carbon steel LR grade A in a thickness 12 mm were joined in butt joint types using GMAW (Gas Metal Arc Welding) with groove’s gap 5 mm and groove angle’s 400 with variation of shielding gas composition. The composition of shielding gas that used were 100% Ar, 100 % CO2 and 50% Ar + 50 % CO2. The measured of mechanical properties with regard to strength, hardness and toughness using, tensile test, bending test, Vickers hardness Test, and Charpy impact test respectively. The physical properties examined with optical microscope. Results show that tensile strength of welding metals are higher than raw materials. Welds metal with mixing Ar + CO shielding gas has the highest tensile strength. Hardness of weld metals with the shielding gas 100% Ar, 100 % CO2 and 50% Ar + 50 % CO2 are 244.9; 209.4; and 209.4 VHN respectively. The temperature of Charpy test was varied to find the transition temperature of the materials. The temperature that used were –60°C, -40°C, -20°C, 0°C, 20°C , and room temperature. Weld metals with various shielding gas have similar trends of toughness flux that was corellated with the microstructure of weld .


2005 ◽  
Vol 475-479 ◽  
pp. 165-168 ◽  
Author(s):  
Ping Yang ◽  
Wang Yue Yang ◽  
Zu Qing Sun

Texture evolutions are determined by XRD and EBSD techniques during ferrite refinement through deformation-enhanced ferrite transformation (DEFT) and dynamic recrystallization (DREX). Evidences of transformation texture, deformation texture and recrystallization texture during DEFT are provided and compared with the texture during DREX. The influence of pass-interval during DEFT on texture is illustrated. Results are discussed in terms of the influences of ferrite grain size and deforming temperature.


1996 ◽  
Vol 36 (10) ◽  
pp. 1279-1285 ◽  
Author(s):  
A. Schmickl ◽  
D. Yu ◽  
C. Killmore ◽  
D. Langley ◽  
T. Chandra

2021 ◽  
Vol 2133 (1) ◽  
pp. 012046
Author(s):  
Lei Chu

Abstract With the rapid development of materials, metal materials are used less and less, but at this stage, metal materials are still widely used, and iron and steel materials are the most widely used. Cracks often appear in the process of metal material processing and use, and these cracks will have a certain impact on the use of metal materials. The existence of microcracks will affect the mechanical properties of materials to some extent, but in most cases, the mechanical properties of materials will be greatly reduced, and in serious cases, metal materials will break directly in the process of use or processing. The crack healing process needed after the emergence of cracks can effectively change this situation, but so far, the research on metal crack healing is still not perfect. In this paper, taking the internal crack of low carbon steel as the object, the recovery of mechanical properties of low carbon steel by cyclic phase transformation heat treatment was studied. The results show that with the increase of the healing area, the microhardness of the area after crack healing also increases, and the tensile strength of the specimen also increases after the healing. When the healing area is similar, increasing the healing time and temperature will result in grain coarsening, resulting in the decrease of microhardness and tensile strength in the crack healing zone.


2005 ◽  
Vol 488-489 ◽  
pp. 589-592 ◽  
Author(s):  
Ming Yi Zheng ◽  
Xiao Guang Qiao ◽  
Shi Wei Xu ◽  
Kun Wu ◽  
Shigeharu Kamado ◽  
...  

Equal channel angular extrusion (ECAE) was applied to an extruded ZW1101 (Mg - 11wt%Zn - 0.9wt%Y) Mg alloy containing quasicrystallines. The as-extruded ZW1101 alloy had an initial grain size of about 12 µm and bands of quasicrystalline phases parallel to the extrusion direction. After the extruded alloy was subjected to ECAE processing, the grain size was refined to about 0.5 µm, and the quasicrystalline phases were further broken and dispersed in the matrix. After the ECAE processing, the micro-hardness and yield strength of the alloy were increased, however, the ultimate tensile strength and the ductility of the alloy were slightly decreased.


2015 ◽  
Vol 1125 ◽  
pp. 195-199
Author(s):  
Toto Triantoro Budi Wardoyo ◽  
S. Izman ◽  
Safian Sharif ◽  
Hosta Ardhyananta ◽  
Denni Kurniawan

In this paper, Shielded Metal Arc Welding (SMAW) was performed on low carbon steel with three types of butt joint (i.e., square, single V, and double V) and uncapping of the weldment. The welding performance is measured based on the mechanical properties (i.e., strength and hardness). Grain size and microstructure of the weldments were also evaluated. The results show that all tested samples show similar tensile strength, which means there was no significant effect of the type of butt joint type or uncapping. The hardness of the weld metal was found to be slightly higher than that of heat affected zone and base metal, in which both showed similar hardness values. The grain size of the weld metal was also finer than that of heat affected zone and base metal. This trend in hardness and grain size on three regions of the welded sample was the same regardless of the butt joint type and whether the weldment was uncapped or not.


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