scholarly journals Estimation of Ferrite Grain Size and Mechanical Properties of a 22MnVNb6 Microalloyed Low Carbon Cast Steel

2017 ◽  
Vol 62 (1) ◽  
pp. 83
Author(s):  
Ganwarich Pluphrach ◽  
Somchai Yamsai
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Microalloyed Steel ◽  
Cast Steel ◽  
Low Carbon ◽  
Cast State ◽  
Transmission Electron ◽  
Microstructural Studies ◽  
Ferrite Grain Size

The ferrite grain size of a 22MnVNb6 microalloyed steel can be estimated by developing a relationship between ferrite grain size, austenitising temperature and cooling rate from austenitising time, temperature. An extended Hall-Petch relationship was used to estimate the yield stress from the estimation ferrite grain size. Heat treatment as the annealing was used to improve the tensile and hardness properties of the steel. It was shown that the best combination of tensile and hardness properties were achieved when a higher austenitising temperature was used. Transmission electron and optical microscopy were used to study the morphology of ferrite and pearlite formed by the heat treatments. The microstructural studies showed that partition of grain by as-cast state was probably the reason for austenite and ferrite grain size improvement. Considering the experimental results, maximum errors of 14.5% and 7.5% were found in the estimation of ferrite grain size and tensile strength, respectively.

The effect of heat treatment on the mechanical properties of a low carbon steel (0.1%) for offshore structural application

2012 ◽  
Vol 226 (3) ◽  
pp. 242-251 ◽  
Author(s):  
Sung S Kang ◽  
Amir Bolouri ◽  
Chung-Gil Kang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Cooling Rate ◽  
Impact Energy ◽  
Cast Steel ◽  
Low Carbon ◽  
Austenite Grain Size ◽  
Tempering Temperature ◽  
Austenite Grain

In this study, a low carbon cast steel (0.1% C) alloy designed for offshore structures, and the mechanical properties of the alloy under different heat treatment cycles have been evaluated. The effect of austenitizing time on the austenite grain size was studied. Subsequently, the quenched samples with minimum austenite grain size subjected to tempering experiments at different tempering temperatures (450 °C, 550 °C, and 650 °C) and cooling rates (0.23, 36, and 50 °C/s) from the temperature. The results showed that by increasing the austenitizing time, the austenite grain size initially decreased and reached the minimum value with ASTM number of 6.35 and then followed by an increase. When the tempering temperature increased, yield and tensile strengths decreased, whereas the ductility properties improved. In addition, yield and tensile strengths were not affected by cooling rate from tempering temperature, whereas the ductility properties were slightly affected. The increase in tempering temperature significantly led to improvement in the toughness to fracture of the alloy. The effect of cooling rate on impact energy for the samples tempered at 450 °C and 550 °C was negligible. By the contrast, impact energy for the samples tempered at 650 °C was markedly affected by cooling rate, in which the highest value was achieved for a cooling rate of 50 °C/s.

A Technology for Producing Hot Rolled Product of Cold Heading Steel

2012 ◽  
Vol 184-185 ◽  
pp. 876-879
Author(s):  
Zhuang Li ◽  
Di Wu ◽  
Wei Lv
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Rolled Product ◽  
Rolling Mill ◽  
Low Carbon ◽  
Controlled Processing ◽  
Hot Rolling Mill ◽  
Hot Rolled ◽  
Ferrite Grain Size

In the present paper, thermomechanical controlled processing (TMCP) of low carbon cold heading steel was conducted by a laboratory hot rolling mill. The results have shown that the mechanical properties of the low carbon cold heading steel can be significantly improved by TMCP without heat treatment. The enhancement of the mechanical properties for the low carbon cold heading steel is attributed mainly to the finer ferrite grain size, and it is also related to the remaining dislocations within substructure of the cold heading steel after deformation. A technology is developed for producing hot rolled product of cold heading steel with improved mechanical properties. The technology has great significance because processing flow is simplified, and manufacture cost is decreased.

scholarly journals Enhancing mechanical properties of a low-carbon microalloyed cast steel by controlled heat treatment

2013 ◽  
Vol 559 ◽  
pp. 427-435 ◽  
Author(s):  
Jingwei Zhao ◽  
Jeong Hun Lee ◽  
Yong Woo Kim ◽  
Zhengyi Jiang ◽  
Chong Soo Lee
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cast Steel ◽  
Low Carbon ◽  
Carbon Microalloyed

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
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Carbon Steel ◽  
Equal Channel Angular Extrusion ◽  
Low Carbon Steel ◽  
Total Elongation ◽  
Low Carbon ◽  
Angular Extrusion ◽  
Ferrite Grain Size

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.

Characterization of Microstructure and Mechanical Properties of a Nb-Microalloyed Steel after Quenching-Partitioning-Tempering Process

2010 ◽  
Vol 654-656 ◽  
pp. 90-93 ◽  
Author(s):  
Xiao Dong Wang ◽  
Zheng Hong Guo ◽  
Yong Hua Rong
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Treatment Process ◽  
Microalloyed Steel ◽  
Heat Treatment Process ◽  
Step Process ◽  
Transmission Electron ◽  
Nb Microalloyed Steel ◽  
Tempering Process

A novel heat treatment process, that is, quenching-partitioning-tempering (Q-P-T) process, has been developed as a new way to obtain ultrahigh strength martensitic structural steel containing retained austenite and alloying carbide. In order to display merit of the Q-P-T process, a medium carbon Nb-microalloyed steel is treated by Q-P-T 1-step process and Q-P-T 2-step process, as well as treated by the transformation induced plasticity heat treatment process and quenching and tempering process, respectively. The results show that Q-P-T samples possess better mechanical properties than those treated by other heat treatment processes. The origin of the good mechanical properties is analyzed based on the phase and microstructure characterization using X-ray diffraction, scanning electron microscopy and transmission electron microscopy.

Effect of Heat Treatment Process on Microstructure and Properties in Low Carbon Si-Mn Q&P Steel

2011 ◽  
Vol 233-235 ◽  
pp. 1009-1013
Author(s):  
Cai Zhao ◽  
Di Tang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Retained Austenite ◽  
Treatment Process ◽  
Lath Martensite ◽  
Heat Treatment Process ◽  
Low Carbon ◽  
Transmission Electron ◽  
Partitioning Time

The mechanical properties of Low Carbon Si-Mn Q&P steel are strongly affected by the conditions of heat treatment. Microstructures and mechanical properties of Low Carbon Si-Mn Q&P steel at different partitioning temperature and holding time was investigated. The microstructure was analysed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is shown that the microstructure of Q&P steel is carbon-depleted lath martensite and carbon enriched retained austenite. The retained austenite appear film-type between the laths. Higher partitioning temperature and longer partitioning time can obtain more retained austenite. It is shown that with increasing partitioning time ultimate tensile strength decreases, while elongation increases obviously. Carbon-enriched metastable retained austenite is considered beneficial because the TRIP phenomenon during deformation can contribute to formability and energy absorption.

Effect of Chromium and Nickel Additions on the Transformation Characteristic and Ferrite Grain Size Refinement of Low Carbon Structural Steels Containing 0.13% C

2016 ◽  
Vol 860 ◽  
pp. 158-164
Author(s):  
Md Mohar Ali Bepari ◽  
Mohiuddin Ahmed
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Optical Microscopy ◽  
Chromium Carbide ◽  
Volume Fraction ◽  
Structural Steels ◽  
Low Carbon ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Ferrite Grain Size

The effect of small addition of chromium and nickel alone or in combination on the transformation characteristic and ferrite grain size of low carbon (0.13%C) structural steels have been studied by cooling suitable steels at four different cooling rates ranging from 120°C/min to 3.6° C/min from temperatures giving a constant austenite grain size of 37 μm. Radio Frequency generator with control system was used for the heat treatment of the steel samples. Optical microscopy of the heat treated samples was carried out. Ferrite grain size was determined from the fictitious ferrite grain size measured by mean linear intercept method and the volume fraction of pearlite obtained by optical microscopy and point counting. It was found that although the heat treatment of the steels was started from a common austenite grain size, their subsequent ferrite grain size after cooling at the same cooling rate were not the same. Both chromium and nickel enhance the formation of Widmanstatten structure. But chromium is more effective than nickel in the formation of Widmanstatten structure. It was also found that the undissolved particles of chromium carbide (Cr2C) present during austenitizing have no role in determining the ferrite grain size. The precipitating particles of chromium carbide (Cr2C) are excellent ferrite grain size refiners. Nickel refines the ferrite grain size. In presence of nickel, Cr2C precipitates are less effective than Cr2C precipitates in absence of nickel in the refinement of ferrite grain size.

Effect of Cooling Paths on Microstructure and Mechanical Properties of Vanadium Bearing Microalloyed Steel

2013 ◽  
Vol 749 ◽  
pp. 243-249
Author(s):  
Jun Chen ◽  
Xiang Wei Chen ◽  
Shuai Tang ◽  
Zhen Yu Liu ◽  
Guo Dong Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Microalloyed Steel ◽  
Final Temperature ◽  
N Value ◽  
Ultra Fast Cooling ◽  
Microstructure And Mechanical Properties ◽  
Cooling Effects ◽  
Fast Cooling ◽  
Ferrite Grain Size

Based on ultra fast cooling, effects of cooling paths on microstructure and mechanical properties of vanadium bearing microalloyed steel were investigated by the observation of optical microscope and scanning electron microscope and the testing of mechanical properties, moreover, the work-hardening exponent was determined based on stress-strain curves. The results show that using ultra fast cooling can effectively refine ferrite grain size and the ferrite grain size is decreased as the final temperature of ultra fast cooling is decreased. In addition, the microstructure and mechanical properties can be controlled by cooling paths. The ferrite-perlite microstructure with lower strength and higher n-value of approx. 0.2 and the ferrite-bainite microstructure with higher strength and lower n-value of approx. 0.16 can be gained at the higher and lower final temperature of ultra fast cooling, respectively. And the yield ratio are all lower than 0.85.

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