Study on the Cooling Process of Low Yield Ratio 590-780MPa Grade Steel Plates for High-Rise Buildings

2011 ◽  
Vol 194-196 ◽  
pp. 292-295 ◽  
Author(s):  
Jian Kang ◽  
Zhao Dong Wang ◽  
Guo Dong Wang
Keyword(s):  
Mechanical Properties ◽  
Structural Steel ◽  
High Strength ◽  
Ferrite Matrix ◽  
Yield Ratio ◽  
Steel Plates ◽  
Air Cooling ◽  
Soft Phase ◽  
Cooling Temperature ◽  
Ultra Fast Cooling

To develop 590/780MPa grade low yield ratio structural steel, the effects of ultra fast cooling (UFC) new process on microstructure and mechanical properties were investigated. The results showed that the low yield ratio and high strength can be obtained by proper phase compositions including relative soft phase and hard phase. For the process of UFC + air cooling, when UFC final cooling temperature was 521°C, 22.5% M-A second hard phases were distributed on bainite ferrite matrix in steel No.A2. The mechanical properties can meet requirement of 590MPa grade low yield ratio structural steel. For the process of air cooling + UFC, when UFC initial cooling temperature was 781°C, the multiphase composed of 28.3% ferrite and other bainite / martensite lath structure can ensure the high strength and low yield ratio of steel No.B1. And performance indexes can meet the requirement of 780MPa grade low yield ratio structural steel.

New Generation TMCP Technology and its Application to 960 MPa High Strength Structural Steel Plates

2014 ◽  
Vol 922 ◽  
pp. 94-101
Author(s):  
Zhao Dong Wang ◽  
Jin Bao Zhu ◽  
Xiang Tao Deng ◽  
Bing Xing Wang ◽  
Yong Tian ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Structural Steel ◽  
New Technology ◽  
High Strength Steels ◽  
High Strength ◽  
Steel Plates ◽  
Ultra Fast Cooling ◽  
Low Temperature Impact Toughness ◽  
New Generation

The new generation thermo-mechanical controlled processing (TMCP) technology based on advanced cooling technique and equipment is introduced here in the context of 960MPa grade high strength structural steel plates. This new technology accurately controls the cooling rate and temperature, with strong influence on phase transformation and precipitation including microstructure and mechanical properties of the steel. The application of the newly developed technology applied to the production of 960MPa grade high strength structural steel demonstrated its effectiveness, especially in improving low temperature impact toughness. The yield strength was 980~1000 MPa and tensile strength 1080~1200 MPa, with impact toughness approaching 150J at-40°C.Keywords: New generation TMCP technology; Ultra fast cooling process; high strength steels; mechanical properties

Development of High-Strength Steel Plates for Low-Temperature Use

1988 ◽  
Vol 110 (3) ◽  
pp. 171-176
Author(s):  
Y. Nakano ◽  
Y. Saito ◽  
K. Amano ◽  
M. Koda ◽  
Y. Sannomiya ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Yield Strength ◽  
Structural Steel ◽  
Welded Joints ◽  
High Strength Steel ◽  
Control Process ◽  
Charpy Impact ◽  
High Strength ◽  
Steel Plates

This paper describes the metallurgical approaches for producing 415MPa and 460MPa yield strength offshore structural steel plates and the mechanical properties of the steel plates and their welded joints. A thermo-mechanical control process (TMCP) was adopted to manufacture YP415MPa and YP460MPa steel plates with weldability comparable to conventional YP355MPa steel plates. The Charpy impact and CTOD tests of the steel plates and their welded joints proved to be very good.

Controlled Cooling Process and Mechanical Property of 590MPa Grade Structural Steel with Low Yield Ratio

2011 ◽  
Vol 261-263 ◽  
pp. 740-743
Author(s):  
Jian Kang ◽  
Zhao Dong Wang ◽  
Guo Yuan ◽  
Guo Dong Wang
Keyword(s):  
Volume Fraction ◽  
Charpy Impact ◽  
High Strength ◽  
Ferrite Matrix ◽  
Yield Ratio ◽  
Controlled Cooling ◽  
Final Temperature ◽  
Ultra Fast Cooling ◽  
High Rise ◽  
New Generation

To develop 590MPa grade low yield ratio steel for high-rise buildings, the new generation TMCP based on ultra fast cooling (UFC) technology was proposed. Then effects of UFC final temperature on microstructure and mechanical properties were investigated. The results show that the control of composite phases is important to obtain high strength, low yield ratio and high work hardening exponent. When UFC final temperature is 521°C, 22.5% (volume fraction) M-A phases are distributed in bainite ferrite matrix, and the excellent overall properties can be obtained, i.e., the yield strength is 570MPa, tensile strength 760MPa, yield ratio 0.75 and percentage elongation 22% with the Charpy impact energy 284J at -40°C. All these indexes can meet the requirements of relevant standards.

Control of Yield Ratio Based on Ultra Fast Cooling and Mechanical Behaviors of High Strength Aseismic Steel

2011 ◽  
Vol 228-229 ◽  
pp. 505-508 ◽  
Author(s):  
Jian Kang ◽  
Guo Yuan ◽  
Zhao Dong Wang
Keyword(s):  
Volume Fraction ◽  
Charpy Impact ◽  
High Strength ◽  
Ferrite Matrix ◽  
Constructional Steel ◽  
Yield Ratio ◽  
Second Phase ◽  
Soft Matrix ◽  
Ultra Fast Cooling ◽  
Fast Cooling

The new generation TMCP process based on ultra fast cooling has recently developed rapidly. In order to develop the low yield ratio constructional steel, the effects of cooling finishing temperature on microstructure and yield ratio of steels were studied primarily. The results show that the high strength and low yield ratio can be achieved by multiphase including M-A hard second phase and bainite ferrite soft matrix. When UFC final temperature is 521°C, the uniform M-A phases with volume fraction of 22.5% are distributed on bainite ferrite matrix, and then the yield strength is 570MPa, tensile strength 760MPa, yield ratio 0.75, and percentage elongation 22% with the Charpy impact energy 284J at -40°C. All these indexes come up to the relevant standards. The steel with lower yield ratio can be subjected to larger plastic deformation before the necking instability.

Microstructure and Mechanical Properties of High Strength Hot-Rolled TRIP Steel Containing Vanadium

2010 ◽  
Vol 160-162 ◽  
pp. 324-329
Author(s):  
Xiao Ying Hou ◽  
Yun Bo Xu ◽  
Di Wu
Keyword(s):  
Mechanical Properties ◽  
Trip Steel ◽  
High Strength ◽  
Ferrite Matrix ◽  
Granular Bainite ◽  
Air Cooling ◽  
Low Carbon ◽  
Multiphase Microstructure ◽  
High Elongation ◽  
Vanadium Carbides

Laboratory hot rolling experiments on a low-carbon TRIP steel containing vanadium have been carried out to study the microstructure characteristics and mechanical properties. The results showed that the multiphase microstructure with ferrite, granular bainite and retained austenite could be obtained if the finish rolling initial temperature was properly decreased and the finishing temperature was controlled in the range of Ae3~ Ar3, and the tensile strength achieved 930 MPa or above. The average ferrite grain size was about 4.5 μm in this experiment, the vanadium nitrides and vanadium carbides precipitated dispersedly within ferritic grains or at grain boundaries, and the higher dislocation density existed in ferrite matrix. EBSD analyses revealed that the high angle boundaries accounted for a large proportion and the misorientation angles were within the interval between 29° and 60° mostly. When the finishing temperature was 800°C and the final air cooling temperature was 630°C, the steel had excellent mechanical properties, which was characterized by combination of high strength(about 930MPa), high elongation(21.7%), low yield/strength ratio(0.49) and as well as high work-hardening exponent(0.23).

Deterioration of Mechanical Properties of High-Strength Pumpcrete after Exposure to High Temperatures

2010 ◽  
Vol 168-170 ◽  
pp. 564-569
Author(s):  
Guang Lin Yuan ◽  
Jing Wei Zhang ◽  
Jian Wen Chen ◽  
Dan Yu Zhu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Heating Rate ◽  
High Strength Concrete ◽  
Heating Temperature ◽  
High Strength ◽  
Air Cooling ◽  
Test Results ◽  
Strength Deterioration ◽  
Residual Compressive Strength

This paper makes an experimental study of mechanical properties of high-strength pumpcrete under fire, and the effects of heating rate, heating temperature and cooling mode on the residual compressive strength(RCS) of high-strength pumpcrete are investigated. The results show that under air cooling, the strength deterioration speed of high-strength concrete after high temperature increases with the increase of concrete strength grade. Also, the higher heating temperature is, the lower residual compressive strength value is. At the same heating rate (10°C/min), the residual compressive strength of C45 concrete after water cooling is a little higher than that after air cooling; but the test results are just the opposite for C55 and C65 concrete. The strength deterioration speed of high-strength concrete after high temperature increases with the increase of heating rate, but not in proportion. And when the heating temperature rises up between 200°C and 500°C, heating rate has the most remarkable effect on the residual compressive strength of concrete. These test results provide scientific proofs for further evaluation and analysis of mechanical properties of reinforced-concrete after exposure to high temperatures.

Study on Metallography Test of the Steel SPV490 for Atmospheric Storage Tank After Fire

2016 ◽  
Author(s):  
Zhou Fang ◽  
Weiwei Hu ◽  
Deyu Liu ◽  
Guanghai Li ◽  
Zhe Wang
Keyword(s):  
Mechanical Properties ◽  
Working Conditions ◽  
Storage Tank ◽  
High Strength ◽  
Air Cooling ◽  
Microscopic Structure ◽  
Water Cooling ◽  
Storage Tanks ◽  
Fire Temperature ◽  
Optical Microstructure

The fire process was simulated by the heat treatment to the Steel SPV490 of atmospheric storage tank, thereby obtaining the metal specimens in different fire temperature, holding time, and cooling modes. And as the temperature increases, the microscopic structure of Steel SPV490 changes under different working conditions, which could be shown in optical microstructure pictures after doing the interception, inlay, polishing, finishing to the specimens. The result shows that, the mechanical properties of the Steel SPV490 for storage tank changes as the temperature rising from the microscopic view. Nodulizing of the cementite in pearlite occurs, and the strength decreases when the high strength steel SPV490 of large atmospheric storage tanks under air cooling condition below 700 °C, however, it equivalents to the normalizing process, as the sorbite occurs in the steel, and the strength increases a bit when the temperature is above 900 °C. The water-cooling of steel SPV490 above 900 °C equivalents to the process of quenching. The occurrence of martensitic substantially increases the strength and the brittleness, and the elongation decreases rapidly.

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