Effect of Nb on Transformation and Property of C-Si-Mn-Cr-Mo High Strength Hot-Rolled DP Steel

2014 ◽  
Vol 510 ◽  
pp. 110-113
Author(s):  
Le Yu Zhou ◽  
Bo Jiang ◽  
Dan Zhang ◽  
Chao Lei Zhang ◽  
Ya Zheng Liu
Keyword(s):  
Volume Fraction ◽  
High Strength ◽  
Strength Increase ◽  
Medium Temperature ◽  
Dp Steel ◽  
Transformation Rules ◽  
Rolling Experiment ◽  
Coiling Process ◽  
Tensile Strength Increase ◽  
Hot Rolled

Two kinds of C-Si-Mn-Cr-Mo tested steels were used to study the transformation rules and microstructure evolution during thermal mechanical experiment and rolling experiment. Effects of micro alloying element Nb on transformation and propertied were discussed. The result shows that Nb retards ferrite transformation, reduces ferrite volume fraction and refines the ferrite grain size and martensite colony size. After micro-alloying of 0.047wt%Nb, yield strength and tensile strength increase by 145MPa and 135MPa respectively under medium temperature coiling process. YS/TS ratio increases from 0.51 to 0.62, meanwhile, the decrease of elongation is not obvious. The grain refining strengthening and precipitation strengthening of Nb micro-alloying is effective to enhance the strength grade of hot rolled DP steel coiled at medium temperature.

Effect of C on Microstructure and Mechanical Property of Hot Rolled DP Steel

2012 ◽  
Vol 557-559 ◽  
pp. 1387-1390
Author(s):  
Le Yu Zhou ◽  
Dan Zhang ◽  
Ya Zheng Liu ◽  
Long Jiao Li
Keyword(s):  
Mechanical Property ◽  
Tensile Strength ◽  
Volume Fraction ◽  
High Strength ◽  
Controlled Rolling ◽  
Elongation Ratio ◽  
Controlled Cooling ◽  
Dp Steel ◽  
Hot Rolled ◽  
Microstructure And Mechanical Property

Two kinds of C-Si-Mn-Cr-Mo-Nb tested steels with different C content were disigned, and controlled rolling and controlled cooling experiment of tested steels have been carried out in lab to analyze the effect of C on microstructure and mechanical property of high strength hot rolled dual phase steel. It is shown that two kinds of tested steels obtained ferrite and martensite microstructure under controlled rolling and step cooling process. With the increase of C content from 0.032wt% to 0.064wt%, ferrite grain size refines from 9.8μm to 5.0μm, width of martensite colony reduces from 10μm to 5.8μm, and martensite volume fraction increases from 11% to 25%. Yielding strength of high C tested steel is higher than that of low C steel by 55MPa, and amplification of tensile strength is about 155MPa. Elongation ratio decreases about 6.4%. Increasing of yielding strength is determined by strengthening of ferrite grain refining. The amplification of tensile strength is effect by volume fraction and refining of strengthening phase.

Effect of Mo on Transformation, Microstructure and Property of Hot-Rolled DP600 Steel

2015 ◽  
Vol 817 ◽  
pp. 560-564
Author(s):  
Le Yu Zhou ◽  
Tian Hao Cui ◽  
Bo Jiang ◽  
Chao Lei Zhang ◽  
Jian Zhong He ◽  
...  
Keyword(s):  
High Strength ◽  
Ferrite Matrix ◽  
Controlled Rolling ◽  
Dual Phase ◽  
Metastable Austenite ◽  
Transformation Zone ◽  
Transformation Rules ◽  
Rolling Experiment ◽  
Hot Rolled ◽  
Soft Ferrite

In according with the transformation rules of C-Si-Mn-Cr and C-Si-Mn-Cr-Mo tested steels, rolling experiment was carried out in lab. to analyze the effect of Mo on transformation, microstructure and property of high strength hot rolled dual phase steels. The results showed that the addition of element Mo decreased start temperature of ferrite transformation and restrains pearlite transformation. There was a metastable austenite zone between ferrite and bainite transformation zone of No.2 steel with 0.35% of Mo. After controlled rolling and step cooling process, dual phase microstructures in which fine martensite islands dispersed in soft ferrite matrix were obtained by two kinds of tested steel. With the addition of Mo, yield strength and tensile strength increased by 80MPa and 60MPa respectively, meanwhile, elongation increased slightly.

Microstructure and Property Control of Hot Rolled DP600 Steel

2011 ◽  
Vol 415-417 ◽  
pp. 938-942
Author(s):  
Le Yu Zhou ◽  
Ya Zheng Liu ◽  
Lian Hong Yang ◽  
Dan Zhang
Keyword(s):  
Dual Phase Steel ◽  
Volume Fraction ◽  
Ferrite Matrix ◽  
Accelerated Cooling ◽  
Dual Phase ◽  
Dp Steel ◽  
Fine Grain ◽  
Mechanical Experiment ◽  
Property Control ◽  
Hot Rolled

Thermal mechanical experiment of step-cooling of 600MPa hot-rolled DP steel after compressed was carried out on Gleeble-1500 thermal mechanical simulator, using design of butterfly-shaped sample. Microstructure evolution during step-cooling and its effect on mechanical property of tested steel were analyzed. It is shown that, dual phase microstructure which martensite islands disperses in fine grain ferrite matrix is obtained by holding for 8~10s at 670°C followed accelerated cooling to 200°C. With increasing of holding time, grain size of ferrite coarsens, and volume fraction of ferrite has few changes. Meanwhile, tensile strengths of tested steel are all near 600MPa. That is to say, ferrite transformation is adequate during holding for 8~10s at 670°C and tensile strength of dual phase steel is stable accordingly.

Effect of Cold Reduction Ratio on Deep-Drawing Performance of High Strength Ti-Nb-If Steel Sheets

2011 ◽  
Vol 415-417 ◽  
pp. 883-888
Author(s):  
Min Li Wang ◽  
Zhi Wang Zheng ◽  
Li Xiao
Keyword(s):  
High Strength ◽  
Strain Ratio ◽  
Reduction Ratio ◽  
Cold Reduction ◽  
Strain Hardening Exponent ◽  
Strength Increase ◽  
If Steel ◽  
Plastic Strain Ratio ◽  
Steel Sheets ◽  
Hot Rolled

Hot rolled high strength Ti-Nb-IF steel sheet was used to study the effect of cold reduction ratio on the microstructures, mechanical properties and textures of experimental steel. The experimental results showed that the recrystallization has finished under different cold reduction ratio. The yield strength, tensile strength, elongation, the plastic strain ratio and strain hardening exponent were approximate 242MPa, 408MPa, 39.5%, 1.8, 0.26. With the cold reduction ratio increase, the textures strength increase, and the α textures have a trend with {111} texture. Therefore, the suggested the optimal cold reduction ratio is 75%, and it obtains optimally match of high strength and punching property.

Ductility of Ultra-High Performance Concrete and its Correlation with Tensile Strength Increase

2015 ◽  
Vol 665 ◽  
pp. 21-24
Author(s):  
B.I. Bae ◽  
Hyun Ki Choi ◽  
Chang Sik Choi
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
High Strength ◽  
Reinforcement Ratio ◽  
Fiber Reinforced Concrete ◽  
Strength Increase ◽  
Ultra High Performance Concrete ◽  
Fiber Volume

In this study, ductility of members with ultra-high performance concrete was investigated using moment-curvature analysis for the verification of safety under large deformation of ultra-high performance concrete structural members. For the analysis of members with ultra-high performance concrete, mathematical stress-strain model was selected among the results conducted by other researchers on the compressive and tensile behavior of high strength concrete and fiber reinforced concrete. According to the investigation on ductility of members with ultra-high performance concrete, decrease of ductility was observed with increase of tensile strength of concrete under the same reinforcement ratio. Members with 2~3% of reinforcement ratio, which usually be used in the field engineering, show the decrease of ductility with increase of fiber volume fraction. As a results of parametric study, limitation of maximum reinforcement ratio ( or limitation of net tensile strain ) suggested by current design code is not safe when using ultra-high performance concrete.

scholarly journals The Kinetics of Phase Transition of Austenite to Ferrite in Medium-Carbon Microalloy Steel

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1986
Author(s):  
Liushun Wu ◽  
Kunlong Liu ◽  
Yun Zhou
Keyword(s):  
Phase Transition ◽  
Volume Fraction ◽  
High Strength ◽  
Effect Of Temperature ◽  
Avrami Equation ◽  
Validation Data ◽  
Medium Carbon ◽  
Hot Rolled ◽  
Kinetics Of ◽  
Transition Kinetic

To reduce energy and resource consumption, high-strength hot-rolled rebars with yield strengths of ≥400 MPa (HRB500) and ≥500 MPa (HRB600) have been designed and produced in recent years. Optimizing the microstructure in the steel to improve strength necessitates determining the kinetics of the phase transition of austenite to polygonal ferrite. Therefore, in the study, the effect of temperature and holding time on the volume fraction of ferrite is investigated in HRB500 and HRB600 steels. Experimental results show that the ferrite percentage initially increases with an increase in temperature and then decreases as the temperature increases from 600 to 730 °C. The optimum temperature range is 680–700 °C for HRB500 steel and 650–680 °C for HRB600 steel. Based on the Johnson–Mehl–Avrami equation, phase transition kinetic models are established. Model predictions are consistent with the validation data. Thus, this study establishes a reference for studying ferrite formation during cooling.

The stabilization of B.C.C. Cu in Cu/Nb nanolayered composites

1996 ◽  
Vol 54 ◽  
pp. 228-229
Author(s):  
H. Kung ◽  
A.J. Griffin ◽  
Y.C. Lu ◽  
K.E. Sickafus ◽  
T.E. Mitchell ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Layer Thickness ◽  
Volume Fraction ◽  
Ion Beam ◽  
High Strength ◽  
Cross Sectional ◽  
Metastable Structure ◽  
High Resolution Tem ◽  
Potential Improvement ◽  
Two Phases

Materials with compositionally modulated structures have gained much attention recently due to potential improvement in electrical, magnetic and mechanical properties. Specifically, Cu-Nb laminate systems have been extensively studied mainly due to the combination of high strength, and superior thermal and electrical conductivity that can be obtained and optimized for the different applications. The effect of layer thickness on the hardness, residual stress and electrical resistivity has been investigated. In general, increases in hardness and electrical resistivity have been observed with decreasing layer thickness. In addition, reduction in structural scale has caused the formation of a metastable structure which exhibits uniquely different properties. In this study, we report the formation of b.c.c. Cu in highly textured Cu/Nb nanolayers. A series of Cu/Nb nanolayered films, with alternating Cu and Nb layers, were prepared by dc magnetron sputtering onto Si {100} wafers. The nominal total thickness of each layered film was 1 μm. The layer thickness was varied between 1 nm and 500 nm with the volume fraction of the two phases kept constant at 50%. The deposition rates and film densities were determined through a combination of profilometry and ion beam analysis techniques. Cross-sectional transmission electron microscopy (XTEM) was used to examine the structure, phase and grain size distribution of the as-sputtered films. A JEOL 3000F high resolution TEM was used to characterize the microstructure.

TENFORM XF450

Alloy Digest ◽  
2007 ◽  
Vol 56 (1) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Alloy Steel ◽  
High Strength ◽  
Bend Strength ◽  
Low Alloy Steel ◽  
Hot Rolled

Abstract The high strength of Tenform XF450, a hot-rolled high-strength low-alloy steel, allows the user to increase the strength of a finished component or to reduce the thickness. The steel is used in the construction and the automotive industries. This datasheet provides information on composition, physical properties, tensile properties. and bend strength. It also includes information on forming. Filing Code: CS-148. Producer or source: Hille & Mueller, USA Inc. See also Alloy Digest CS-173, November 2012.

STRENX SECTION 900

Alloy Digest ◽  
2017 ◽  
Vol 66 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
High Strength ◽  
Bend Strength ◽  
Bend Channel ◽  
Cold Formed Steel ◽  
The Common ◽  
Hot Rolled ◽  
Common Shape ◽  
Minimum Yield ◽  
Steel Section

Abstract Strenx Section 900 is a cold-formed steel section made of hot-rolled, high-strength steel with a minimum yield strength of 900 MPa (131 ksi). Its high strength combined with naturally stiff form enables construction of stronger and lighter structures. The common shape is a U-bend channel. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on forming, machining, and joining. Filing Code: SA-792. Producer or source: SSAB Swedish Steel Inc..

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