Microstructure and Precipitation of a High Strength Microalloyed Steel

2014 ◽  
Vol 508 ◽  
pp. 12-15
Author(s):  
Hai Lin Yang ◽  
Guang Xu ◽  
Yi Zhang ◽  
Min Wang ◽  
Ming Xing Zhou
Keyword(s):  
Yield Strength ◽  
High Strength Steel ◽  
Microalloyed Steel ◽  
High Strength ◽  
Fine Scale ◽  
Factors Affecting ◽  
Research Results

Microstructure and precipitation of a Ti-Nb microalloyed high-strength steel were studied. The objective of the study is to examine the factors affecting yield strength and the effect of processing temperatures on microstructure and precipitation. The research results indicate that the dominant factors responsible for yield strength are fine ferrite grains and fine-scale carbonitride precipitatates, which are affected by processing temperatures. The influence of reheating temperature on precipitates was analyzed. Moreover, the optimum reheating temperatures is suggested for Ti-Nb microalloyed high-strength steel.

High-Strength Steel Hot Forming Mechanics Performance and Characteristic Experimental Study

2016 ◽  
Vol 693 ◽  
pp. 800-806
Author(s):  
You Dan Guo
Keyword(s):  
Yield Strength ◽  
High Strength Steel ◽  
High Strength ◽  
High Energy ◽  
Absorption Capacity ◽  
Hot Forming ◽  
Gas Content ◽  
Strength Increase ◽  
Gradual Change ◽  
Forming Process

In high-strength steel hot forming, under the heating and quenching interaction, the material is oxidized and de-carbonized in the surface layer, forming a gradual change microstructure composed of ferrite, ferrite and martensite mixture and full martensite layers from surface to interior. The experiment enunciation: Form the table to ferrite, ferrite and martensite hybrid organization, completely martensite gradual change microstructure,and make the strength and rigidity of material one by one in order lower from inside to surface, ductility one by one in order increment in 22MnB5 for hot forming;Changes depends on the hot forming process temperature and the control of reheating furnace gas content protection, when oxygen levels of 5% protective gas, can better prevent oxidation and decarburization;Boron segregation in the grain boundary, solid solution strengthening, is a major cause of strength increase in ;The gradual change microstructure in outer big elongation properties, make the structure of the peak force is relatively flat, to reduce the peak impact force of structure, keep the structure of high energy absorption capacity;With lower temperature, the material yield strength rise rapidly,when the temperature is 650 °C, the yield strength at 950 °C was more than 3 times as much.

scholarly journals Research on Concrete Columns Reinforced with New Developed High-Strength Steel under Eccentric Loading

2019 ◽  
Author(s):  
Yonghui Hou ◽  
Shuangyin Cao ◽  
Xiangyong Ni ◽  
Yizhu Li
Keyword(s):  
Yield Strength ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Lower Amount ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Small Eccentricity ◽  
Failure Patterns

The use of new developed high-strength steel in concrete members can reduce steel bars congestion and construction costs. This research aims to study the behavior of concrete columns reinforced with new developed high-strength steel under eccentric loading. Ten reinforced concrete columns were fabricated and tested. The test variables are transverse reinforcement amount and yield strength, eccentricity, and longitudinal reinforcement yield strength. The failure patterns are compression and tensile failure for columns subjected to small eccentricity and large eccentricity, respectively. The same level of post-peak deformability and ductility only can be obtained with lower amount of transverse reinforcement when high-strength transverse reinforcements are used in columns subjected to small eccentricity. The high-strength longitudinal reinforcement can improve bearing capacity and post-peak deformability of concrete columns. Besides, three different equivalent rectangular stress block (ERSB) parameters in predicting bearing capacity of columns with high-strength steel were discussed based on test and simulated results. It is concluded that the Code of GB 50010-2010 overestimates the bearing capacity of columns with high-strength steel, whereas bearing capacities computed using Codes of ACI 318-14 and CSA A23.3-04 agree well with test results.

scholarly journals Research on Concrete Columns Reinforced with New Developed High-Strength Steel under Eccentric Loading

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2139 ◽  
Author(s):  
Yonghui Hou ◽  
Shuangyin Cao ◽  
Xiangyong Ni ◽  
Yizhu Li
Keyword(s):  
Yield Strength ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Lower Amount ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Small Eccentricity ◽  
Failure Patterns

The use of new developed high-strength steel in concrete members can reduce steel bar congestion and construction costs. This research aims to study the behavior of concrete columns reinforced with new developed high-strength steel under eccentric loading. Ten reinforced concrete columns were fabricated and tested. The test variables were the transverse reinforcement amount and yield strength, eccentricity, and longitudinal reinforcement yield strength. The failure patterns were compression and tensile failure for columns subjected to small eccentricity and large eccentricity, respectively. The same level of post-peak deformability and ductility could only be obtained with a lower amount of transverse reinforcement when high-strength transverse reinforcements were used in columns subjected to small eccentricity. The high-strength longitudinal reinforcement improved the bearing capacity and post-peak deformability of the concrete columns. Furthermore, three different equivalent rectangular stress block (ERSB) parameters for predicting the bearing capacity of columns with high-strength steel are discussed based on test and simulated results. It is concluded that the China Code GB 50010-2010 overestimates the bearing capacity of columns with high-strength steel, whereas the bearing capacities computed using the America Code ACI 318-14 and Canada Code CSA A23.3-04 agree well with the test results.

Experimental Study on Axial Compression Performance of Full-Scale Square Columns of Reinforced Concrete Confined by High-Strength Reinforcement Hoops

2012 ◽  
Vol 446-449 ◽  
pp. 981-988
Author(s):  
Zhen Bao Li ◽  
Wen Jing Wang ◽  
Wei Jing Zhang ◽  
Yun Da Shao ◽  
Bing Zhang ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Yield Strength ◽  
Bearing Capacity ◽  
Axial Compression ◽  
High Strength Steel ◽  
High Strength ◽  
Concrete Columns ◽  
Full Scale ◽  
Compression Performance ◽  
Deformation Ability

Axial compression experiments of four full-scale reinforced concrete columns of two groups were carried out. One group of three columns used high-strength steel with the yield strength of 1000MPa as reinforcement hoops, and the second group used the ordinary-strength steel with yield strength of 400MPa. The axial compressive performances between these two groups were assessed. Compared to the specimen using the ordinary-strength steel, the axial compressive bearing capacity of using the high strength steel dose not increase significantly, while the deformation ability increases greatly. The results also indicate that the stress redistributions of the hoops and the concrete sections are obvious, and long-lasting when specimens achieve the ultimate bearing capacity after the yield of the rebar and local damage of concrete materials, at this time the strain of the specimens developes a lot, especially stress - strain curves of speciments with high-strength hoop all show a wide and flat top.

The Bauschinger Effect in a High-Strength Steel

1966 ◽  
Vol 88 (2) ◽  
pp. 480-488 ◽  
Author(s):  
R. V. Milligan ◽  
W. H. Koo ◽  
T. E. Davidson
Keyword(s):  
Heat Treatment ◽  
Yield Strength ◽  
Strain Hardening ◽  
Uniaxial Tension ◽  
High Strength Steel ◽  
Bauschinger Effect ◽  
High Strength ◽  
The Other ◽  
Material Structure ◽  
Permanent Strain

The object of this work was to evaluate quantitatively the Bauschinger effect in a 4330 modified steel as a function of strength level and structure as derived from variations in heat-treatment. Material having martensitic, pearlitic, and bainitic structures was studied utilizing a uniaxial tension-compression specimen. Various ways of defining the magnitude of the Bauschinger effect are explained. One is a conventional approach as suggested by Welter, the other a technique which takes strain-hardening into account. The results show the Bauschinger effect to be independent of yield strength for three different strength levels of the martensitic material. It is only mildly influenced by material structure and independent of the direction of overstrain. The Bauschinger effect increases with increasing permanent strain up to approximately 2 percent and thereafter remains essentially constant.

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.

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