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Hao L.,CAS Shenyang Institute of Metal Research | Zhang S.,Northeastern University China | Zhang S.,Laiwu Steel Group | Dong J.,CAS Shenyang Institute of Metal Research | Ke W.,CAS Shenyang Institute of Metal Research
Corrosion Science | Year: 2012

The corrosion evolution of a Mo-Cu-bearing fire-resistant steel in a simulated industrial atmosphere was investigated by corrosion weight gain, XRD, EPMA, XPS, and polarization curves. The results indicate that the corrosion kinetics is closely related to the rust composition and electrochemical properties. As the corrosion proceeds, the relative content of γ-FeOOH and Fe3O4 decreases and α-FeOOH increases, and the rust layer becomes compact and adherent to steel substrate. Molybdenum and copper enrich in the inner rust layer, especially at the bottom of the corrosion nest, forming non-soluble molybdate and Cu(I)-bearing compounds responsible for enhanced corrosion resistance of the rust layer. © 2011.


Hao L.,CAS Shenyang Institute of Metal Research | Zhang S.,Northeastern University China | Zhang S.,Laiwu Steel Group | Dong J.,CAS Shenyang Institute of Metal Research | Ke W.,CAS Shenyang Institute of Metal Research
Corrosion Science | Year: 2012

The evolution of atmospheric corrosion of MnCuP weathering steel in a simulated coastal-industrial atmosphere was investigated by weight gain, SEM, XRD, and electrochemical measurements. The results indicate that the corrosion kinetics divides into two stages with a higher corrosion rate in the first stage and a lower rate in the second stage. The increased amount of α-FeOOH indicates an improved resistance of the rust. The rust enhances initially and then stabilizes the cathodic process, but the anodic process tends to be inhibited. The EIS results indicate that the protective ability of the rust layer can be evaluated by the charge transfer resistance. © 2012.


Hao L.,CAS Shenyang Institute of Metal Research | Zhang S.,Northeastern University China | Zhang S.,Laiwu Steel Group | Dong J.,CAS Shenyang Institute of Metal Research | Ke W.,CAS Shenyang Institute of Metal Research
Corrosion Science | Year: 2011

In this work, atmospheric corrosion resistance of low cost MnCuP weathering steel in simulated coastal, industrial, and coastal-industrial atmospheric environments was investigated by wet/dry cyclic acceleration corrosion tests. The results indicate that MnCuP weathering steel exhibits high corrosion resistance in the three atmospheres. Besides, the alloying effect of Mn, Cu, and P elements on the anti-corrosion mechanism of MnCuP weathering steel was discussed by techniques of X-ray photoelectron spectroscopy, potential-pH diagram, and electron probe microanalysis. © 2011.


Hao L.,CAS Shenyang Institute of Metal Research | Zhang S.,Northeastern University China | Dong J.,CAS Shenyang Institute of Metal Research | Ke W.,Laiwu Steel Group
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2012

The rusting evolution of MnCuP weathering steel in a simulated industrial atmosphere as a function of corrosion duration was investigated by corrosion weight gain, scanning electron microscopy, X-ray diffraction, and electrochemical methods. The results indicate that the corrosion kinetics is related closely to the rust composition and electrochemical properties. The corrosion rate is higher during the first corrosion stage, and it is lower during the second corrosion stage. During the first corrosion stage, the rust layer is in low density, discontinuous, and loose, with a lower relative abundance of a-FeOOH. During the second corrosion stage, a compact and protective inner rust layer forms with a higher relative abundance of a-FeOOH, contributing to enhanced rust layer resistance. The rust initially enhances and then stabilizes the cathodic process, but the anodic process tends to be inhibited by the protective rust layer. Electrochemical impedance spectroscopy tests indicate that it is more scientific to evaluate the rust layer protective ability by charge transfer resistance. © 2011 The Minerals, Metals & Materials Society and ASM International.


Hao L.,CAS Shenyang Institute of Metal Research | Zhang S.,Northeastern University China | Zhang S.,Laiwu Steel Group | Dong J.,CAS Shenyang Institute of Metal Research | Ke W.,CAS Shenyang Institute of Metal Research
Corrosion Science | Year: 2012

The evolution of rust on MnCuP weathering steel submitted to a simulated coastal atmosphere was investigated by corrosion weight gain, scanning electron microscopy, X-ray diffraction, and electrochemical methods. The results indicate that the higher corrosion rate during the first stage than that during the second stage is related closely to the rust composition and electrochemical properties. The corrosion rate evolution is caused by the formation of a protective rust layer with a higher relative amount of α-FeOOH. The rust initially enhances and then stabilizes the cathodic process, but the anodic process tends to be inhibited by the protective rust layer. © 2012.


Cai X.,Northeastern University China | Liu C.,Laiwu Steel Group | Liu Z.,Northeastern University China
Materials and Design | Year: 2014

We investigate here the three-stage cooling process of dual phase (DP) steels with the prepositional ultra fast cooling (UFC) equipment, which is different with the DP production line, with UFC in the end. Two dimensional finite difference model (FEM) was used to calculate the temperature field during the cooling process and classical thermodynamic model is used to develop CCT diagram. The temperature field and phase transformation process are combined to predict the microstructure and the mechanical properties across the cross-section using the thermodynamic model and the empirical model. The experiments present good mechanical properties of DP steels, which proved the production of DP steels with the prepositional UFC equipment is feasible. © 2013 The Authors.


Liu J.,Laiwu Steel Group
Jinshu Rechuli/Heat Treatment of Metals | Year: 2015

Effects of different quenching and tempering processes on microstructure and properties of 35CrMo steel plate were studied. The results show that when heating at 790℃, incomplete austenization of the steel leads to nonuniformity of microstructure. When at 850℃ and higher, little change of microstructure happens. With the tempering temperature rising, hardness of the steel reduces. Finally the field production process of the 35CrMo steel plate is heated at 850℃ for 60 min and water quenched then tempered at 620℃ for 100 min. With this heat treatment process, the properties of the steel plate are stable and it creates good economic benefits for the enterprise. ©, 2015, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.


Yang J.,Laiwu Steel Group
Jinshu Rechuli/Heat Treatment of Metals | Year: 2013

For high yield ratio of 800 MPa grade high strength low alloy steel plate, the relationships between mechanical properties, structure and production process parameters were analyzed by optical microscope, scanning electron microscopy and transmission electron microscopy. The results show that through a series of measures of reducing start cooling temperature, increasing final cooling temperature and reducing tempering temperature, controlling appropriate volume fraction of each phase in the microstructure, the yield ratio of the steel decreases from 0.964 to 0.825.


Zou Z.,Laiwu Steel Group
Jinshu Rechuli/Heat Treatment of Metals | Year: 2015

Rapid heat treatment simulation test of TRIP590 steel under different process conditions was conducted by using the continuous annealing simulation testing machine. The microstructure and mechanical properties of the steels were investigated by OM, TEM and tensile tester. The results show that the product of strength and plasticity is influenced the first by aging temperature, the second by annealing temperature in two phase region and the third by aging time. The best combination process is annealing at 850 ℃, and aging at 430 ℃ for 420 s, which could reach the most product of strength and plasticity. ©, 2015, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.


Patent
Laiwu Steel Group | Date: 2011-10-26

The present invention provides a smelting furnace (9), which comprises: a furnace body, a feeding element, an outlet for steel and a coal-oxygen gun (12) for blowing oxygen gas and a carbon-containing material into steel slag. The present invention further provides a steel-making process by applying said smelting furnace (9), a continuous steel-making apparatus comprising said smelting furnace (9) and a steel-making process by applying said continuous steel-making apparatus.

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