Relationship between Rockwell hardness and pearlite lamellar spacing of hardened layer under different cooling rates for U75 V 60 kg m −1 heavy rail

2021 ◽  
Vol 52 (4) ◽  
pp. 460-467
Author(s):  
H. Kang ◽  
Z.H. Wang ◽  
Y.Y. Li ◽  
C.N. Li
Keyword(s):  
Lamellar Spacing ◽  
Hardened Layer ◽  
Rockwell Hardness ◽  
Cooling Rates ◽  
Heavy Rail

The Influence on the Hardness and Form of U75V from the Different Cooling Rates

2014 ◽  
Vol 541-542 ◽  
pp. 83-89 ◽  
Author(s):  
Peng Fei Wang ◽  
Ran Wei ◽  
Zhi Min Liu ◽  
Lin Chen ◽  
Ge Li
Keyword(s):  
Phase Diagram ◽  
Data Analysis ◽  
Chemical Properties ◽  
Lamellar Microstructure ◽  
Lamellar Spacing ◽  
Thermal Simulation ◽  
Grain Structure ◽  
Rockwell Hardness ◽  
Cooling Rates ◽  
Microstructure Observation

This paper analyzes the TTT and CCT curves of U75V as a research basis, detailed anatomical U75V chemical properties and grain structure, through thermal simulation machine, heating 820 °C, respectively, and 920 °C, respectively, the sample detection U75V 2 °C / s, 4 °C / s, 6 °C / s, 10 °C / s, 15 °C / s, 20 °C / s speeds cooled Rockwell hardness, and observing samples taken U75V phase diagram. Through data analysis and image contrast, pearlite lamellar microstructure observation, analysis hardness and lamellar spacing, summed pairs of different cooling rates U75V organizations and hardness.

Study of Quenching Organization Property under Wind Cooling Condition

2014 ◽  
Vol 487 ◽  
pp. 682-686
Author(s):  
Fu Quan Tu ◽  
Yang Mao ◽  
Ren Bo Xu
Keyword(s):  
Surface Hardness ◽  
Hardened Layer ◽  
Spray Cooling ◽  
Cooling Time ◽  
Cooling Condition ◽  
Micro Structure ◽  
Cross Sectional ◽  
Quenching Process ◽  
Quenching Time ◽  
Heavy Rail

In this paper, the steel of U71Mn specifications for 60kg/m heavy rail is seen as a research object. Experimental method is employed to study the heavy rail hardened layer, including surface hardness, micro-structure and cross-sectional hardness under different cooling time during quenching. Experimental results showed that obtained heavy rail after wind cooling quenching finally met the Tb/T2344-2003 43-75 kg/m standard. Best quenching treatment condition is found and the defect is reduced to large extent when quenching time is 40 seconds, cooling time is 40 to 45 seconds, superior to the traditional spray cooling condition. These results provide an important reference for the quenching process of heavy rail.

The Influence of Laser Hardening on the Microstructure and Wear Resistance of Disk Opener

2010 ◽  
Vol 97-101 ◽  
pp. 1497-1501 ◽  
Author(s):  
Hao Sun ◽  
Gang Ling ◽  
Hong Wen Li ◽  
Yan Bo Su ◽  
Shao Ping Xiong ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Phase Transformation ◽  
Laser Power ◽  
Hardened Layer ◽  
Solid State Laser ◽  
Laser Hardening ◽  
Rockwell Hardness ◽  
Transformation Zone ◽  
Hardness Tester ◽  
Melted Zone

The microstructure and properties of hardened layer of 45 steel disk opener with a variety of parameters of HLD1001.5 solid-state laser were studied by SEM, Rockwell hardness tester and wear tester. The results showed that under the conditions of the laser power from 400W to 600W, the hardened layer is composed of melted zone, phase transformation zone and heat affected zone, and the hardness is up to 58.5-61HRC, and the disk openers have excellent wear resistance after the laser hardening, which is best in the disk opener with the treatment of laser power 500W.

scholarly journals Estimation Of Cooling Rates In Suction Casting And Copper-Mould Casting Processes

2015 ◽  
Vol 60 (2) ◽  
pp. 767-771 ◽  
Author(s):  
T. Kozieł
Keyword(s):  
Lamellar Spacing ◽  
Cooling Rates ◽  
Eutectic Transformation ◽  
Cu Alloys ◽  
Ni Alloy ◽  
Mould Casting ◽  
Cylindrical Samples ◽  
Copper Mould ◽  
Microstructural Examination ◽  
Made In

Abstract The cooling rates associated with suction and copper-mould casting of ø2, ø3 and ø5 mm rods made in Fe-25wt%Ni and Al-33wt%Cu alloys were determined based on their cellular and lamellar spacings, respectively. The work showed that the temperature profile in cylindrical samples can not be determined merely by microstructural examination of eutectic sample alloys. A concave solidification front, as a result of eutectic transformation, caused decrease of a lamellar spacing while approaching to the rod centre. The minimum axial cooling rates, estimated based on the cellular spacing in the Fe-25wt%Ni alloy, were evaluated to be about 200 K/s for both ø2 and ø3 mm and only 30 K/s for the ø5 mm suction cast rods. The corresponding values were slightly lower for the copper-mould cast rods.

scholarly journals The Effect of Solidification Rate on the Microstructure and Mechanical Properties of Pure Magnesium

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1264
Author(s):  
Murtatha M. Jamel ◽  
Hugo Lopez ◽  
Benjamin Schultz ◽  
Wilkistar Otieno
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Fracture Behavior ◽  
Solidification Rate ◽  
Casting Process ◽  
Grain Structure ◽  
Rockwell Hardness ◽  
Cooling Rates ◽  
Liquid Co2 ◽  
Processing Defects

Magnesium, Mg, has been widely investigated due to its promising potential as magnesium alloys for various applications, particularly as biomedical implantation devices among other medical applications. This work investigates the influence of different cooling rates on the strength of pure Mg. The cooling rates were set to cover a low cooling rate LCR (0.035 °C/s) in an insulated furnace, a moderate cooling rate MCR (0.074 °C/s) in uninsulated-ends furnace, and a high cooling rate HCR (13.5 °C/s) in liquid CO2. The casting process was accomplished using a closed system of melting and cooling due to the reactivity-flammability of magnesium in order to minimize processing defects and increase the safety factor. The as-cast samples were metallographically examined for their microstructure, and properties such as impact strength, hardness, and tension were determined. Increasing the solidification rate from 0.035 °C/s to 0.074 °C/s increased the hardness from 30 to 34 Rockwell Hardness and the UTS from 48 to 67 MPa. A higher solidification rate of 13.5 °C/s further enhanced the hardness to 48 Rockwell Hardness and the UTS to 87 MPa in comparison to the 0.074 °C/s cooling rate. Additionally, the fracture behavior and morphology were investigated. It was found that in general, the mechanical properties tended to improve by refining the grain structure.

Effect of Cooling Rates after Finish Rolling on Microstructure and Properties of Microalloyed Steels Used for Fracture Splitting Con-Rods

2011 ◽  
Vol 284-286 ◽  
pp. 1053-1059
Author(s):  
Xian Zhong Zhang ◽  
Gui Feng Zhou ◽  
Qing Feng Chen ◽  
Yu Zhang Xiong
Keyword(s):  
Cooling Rate ◽  
High Strength ◽  
Lamellar Spacing ◽  
Microalloyed Steels ◽  
Cooling Rates ◽  
Microstructure And Properties ◽  
Finish Rolling ◽  
Fracture Splitting ◽  
Carbon Microalloyed ◽  
The Impact

The effect of cooling rates after finish rolling on microstructure and properties of high strength medium carbon microalloyed steels used for fracture splitting con-rods was investigated using the methods of optical microscopy, SEM and TEM, etc. The results show that high cooling rate after finish rolling can increase the percentage of pearlite, reduce the grain size of ferrite and lamellar spacing of pearlite. The precipitations in the steel are composite phases of (V,Ti)(C,N), etc. Their granularity are about 30-170nm, and they will decrease with the speeding up cooling. The yield strength (YS) and ultimate tensile strength (UTS) are improved with increasing the cooling rate. The impact fracture surface shows distinct brittle fracture character.

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