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He C.-L.,University of Science and Technology Beijing | Zhu R.,University of Science and Technology Beijing | Dong K.,University of Science and Technology Beijing | Qiu Y.-Q.,University of Science and Technology Beijing | Sun K.-M.,Tianjin Pipe Group Corporation Ltd
Journal of Iron and Steel Research International

A transient three-dimensional mathematical model has been developed to analyze the three-phase flow in a 150 t EAF (electric arc furnace) using oxygen. VOF (multiphase volume of fluid) method is used to simulate the behaviors of molten steel and slag. Numerical simulation was conducted to clarify the transient phenomena of oxygen impingement on molten bath. When oxygen jet impinges on the surface of molten bath, the slag layer is broken and the penetrated cavity in molten steel is created. Simultaneously, the wave is formed at the surface of uncovered steel on which the slag layer is pushed away by jet. The result of numerical simulations shows that the area and velocity of uncovered steel created by impingement, jet penetration depth change from 0.10 m 2, 0.0125 m/s, 3.58 cm to 0.72 m 2, 0.1445 m/s, 11. 21 cm, when the flow rate of an oxygen lance varies from 500 to 2000 m 3/h. The results have been validated against water model experiments. More specially, the relation between the penetration depth and oxygen flow rate predicted by numerical simulation has been found to agree well with that concluded by water model. © 2011 Central Iron and Steel Research Institute. Source

Qiu H.,Japan National Institute of Materials Science | Wang L.,Tianjin Pipe Group Corporation Ltd | Hanamura T.,Japan National Institute of Materials Science | Torizuka S.,Japan National Institute of Materials Science
ISIJ International

A study was conducted to demonstrate physical interpretation of grain refinement-induced variation in fracture mode in ferritic steel. Tensile tests were performed at room temperature and at a crosshead rate of 0.4 mm/min with specimens of 4 mm in diameter and 10 mm in gage length to investigate the dependence of critical fracture strain on ferrite grain size. Round smooth tensile specimens were applied to conduct the investigations where they were in uniaxial stress state before the onset of necking and turned into triaxial state after necking. The stress triaxiality in the region ahead of the crack was higher than that in the round smooth tensile specimen for a sample with a crack as the crack tip was sharp. The fracture strain obtained from tensile tests was larger than the critical fracture strain in the local region ahead of the crack. Source

Qiu H.,Japan National Institute of Materials Science | Qi J.G.,Liaoning University of Technology | Wang L.N.,Tianjin Pipe Group Corporation Ltd | Yin F.X.,China First Heavy Industries | Hiraoka K.,Osaka University
Materials Science and Technology (United Kingdom)

As environmental temperature decreases, the amount of retained austenite is more likely to greatly reduce due to the thermal austenite-martensite transformation caused by the decreased thermal stability of retained austenite, probably making its amount lower than the required content. In the present study, the thermal stability of retained austenite in Cr-Ni weld metals was investigated to see whether sufficient retained austenite can be maintained at low temperatures. The specific experimental procedure is as follows: briefly, the samples were cooled in turn from room temperature to 0,-20,-40,-60,-80,-100 and-196°C; the amount of retained austenite at the above temperatures was measured using X-ray diffraction. Through investigating the dependence of the content of retained austenite on temperature, it was revealed that when the content of retained austenite is <20%, retained austenite can be maintained until-196°C. © 2013 Institute of Materials, Minerals and Mining. Source

Tianjin Pipe Group Corporation | Date: 2016-03-04

metal cylinder pipes; Steel pipes; seamless steel pipes; metal mechanical pipes.

Tianjin Pipe Group Corporation | Date: 2010-05-11

Poles of metal; common metals, unwrought or semi-wrought for further manufacture; steel sheets; laths of metal; elbows of metal for pipes; junctions of metal for pipes; pipes of metal; building boards and panels of metal; steel pipes; casings of metal for oilwells.

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