Jiangsu Yinhuan Precision Steel Tube Co Ltd

Yicheng, China

Jiangsu Yinhuan Precision Steel Tube Co Ltd

Yicheng, China
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Li D.,Jiangsu University | Dai Q.,Jiangsu University | Wang G.,Jiangsu Yinhuan Precision Steel Tube Ltd Company | Shao X.,Jiangsu Yinhuan Precision Steel Tube Ltd Company | Wang R.,Jiangsu University
Jiangsu Daxue Xuebao (Ziran Kexue Ban)/Journal of Jiangsu University (Natural Science Edition) | Year: 2012

The high-temperature oxidation properties of Super304H and Super304HS austenitic heat-resis-tance stainless steels at various temperatures were investigated by weighting method. The results indicate that the dynamic oxidation curves of both Super304H and Super304HS show parabolical figure. The oxidation resistance property of Super304HS is markedly better than that of Super304H, and the oxidation scale of Super304H is obviously chipped off after the treatment at 900°C for 100 h. Surface morphologies and structure of oxidation scales were analyzed by SEM and XRD. The results show that similar composition of Cr 2O 3 with small FeCr 2O 4 was detected in the two types of oxidation scales at 700°C and 800°C. The oxidation scale of Super304H at 900°C mainly contains Cr 2O 3, Fe 2O 3 and FeCr 2O 4, while only Cr 2O 3 and FeCr 2O 4 are observed in oxidation sacle of Super304HS.


Cheng X.,Jiangsu University | Wang C.,Jiangsu University | Zhang N.,Jiangsu University | Li D.,Jiangsu University | And 2 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2016

Creep property of a novel Cr18Ni9NbTiN austenitic stainless steel at 650 ℃ and different stresses was investigated by RDL100 high temperature electrical creep machine. Microstructure of the Cr18Ni9NbTiN steel at different creep stage under 220 MPa were observed and analyzed by using SEM, TEM and EDS. The results show that during initial-state creep stage, intracrystalline dislocation density increases dramatically, tangled dislocation is found, tiny NbN precipitates disperse distribute within the grain. During steady-state creep stage, dislocations form reticular structure, TiN particles separates out from the grains, chain (Cr, Fe)23C6 precipitates along grain boundaries, reticular dislocation and precipitated second phase not only reduce the mobility of dislocation together, but also improve the creep resistance of the alloy. During accelerate-state creep stage, a large number of extended dislocations appeared which extend the creep life of the steel. Creep rupture of Cr18Ni9NbTiN steel belongs to intergranular brittle fracture, some of (Cr, Fe)23C6 precipitates on the grain boundary exfoliated, wedge cracks are found at trigeminal grain boundary. © 2016, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.


Li D.,Jiangsu University | Dai Q.,Jiangsu University | Wang R.,Jiangsu University | Wang G.,Jiangsu Yinhuan Precision Steel Tube Co. | Liu Y.,Jiangsu Yinhuan Precision Steel Tube Co.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2013

The unqualified TP304L pipes applied to ultra-supercritical thermal power units were analyzed by the JSM-7001F scanning electron microscope, Inca Energy350X energy spectrometer, etc. It is found a certain depth of corrosion occurred on the inside surface of the unqualified TP304L pipes in form of intergranular corrosion cracking. Microstructure analysis shows that there are more carbides precipitated at the grain boundaries on the inner surface of the pipes, and fewer on the outer surface or in the center of the pipes. It is considered that the intergranular corrosion cracking and carbide precipitation are due to high temperature and rapid carburizing during production.


Li D.-S.,Jiangsu University | Li D.,Jiangsu University | Dou H.,Jiangsu Yinhuan Precision Steel Tube Co Ltd | Gao P.,Jiangsu Yinhuan Precision Steel Tube Co Ltd | And 4 more authors.
Key Engineering Materials | Year: 2014

The oxidation kinetic curves of four kinds of austenitic stainless steel at 700? was measured by weighting method. It is showed that the oxidation curves of those austenitic stainless steels follow the parabolic law. The mass gain of 800Al steel. is the least of all. The surfacemorphology and structure of the oxide scale were studied by scanning electron microscopy and X-ray diffraction methods. It is found that adense oxide scale formed at 700? in all four austenitic stainless steels. In austenitic stainless steel with high Mn content, scales are mainly composed of Mn2O3 and the spinel MnFe2O4. Scales of austenitic stainless steel with high Cr content but without element Al are composed by Cr2O3 and the small amount of spinel FeCr2O4 . Scales of austenitic stainless steel with element Al and Cr are composed of(Fe0.6Cr0.4)2O3 and Al oxide, showing the excellent oxidation resistance property. ©2014 Trans Tech Publications Ltd, Switzerland.


Li D.-S.,Jiangsu University | Dai Q.-X.,Jiangsu University | Cheng X.-N.,Jiangsu University | Chen Z.-W.,Jiangsu University | And 2 more authors.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2011

High-temperature oxidation dynamics of austenitic heat resistant stainless steel Cr18Ni3Mn11Cu3NbN under different temperatures was studied using weighting method. The results indicate that the parabolic type oxidation dynamic curve is observed and excellent oxidation resistance is exhibited at temperatures of 700 and 800°C, based on the standard of average oxidation velocity for the steel. The surface morphology and structure of the oxidation scale were analyzed by SEM and XRD. The oxidation scale at 700°C mainly consisted of Mn2O3, MnFe2O4 (spinel structure) and Cr oxides. At 800°C, Fe oxides are identified, and the scale started to peel off. At 900°C, the scale is composed of Mn2O3, Fe2O3 and MnFe2O4, and severe delamination occurred.


Li D.-S.,Jiangsu University | Dai Q.-X.,Jiangsu University | Cheng X.-N.,Jiangsu University | Shao X.-Z.,Jiangsu Yinhuan Precision Steel Tube Co. | Wang G.-J.,Jiangsu Yinhuan Precision Steel Tube Co.
Cailiao Rechuli Xuebao/Transactions of Materials and Heat Treatment | Year: 2012

Based on the experimental data and the extensive results of the author's research, the author studied the relation between elements and mechanical properties of austenitic stainless steels at room temperature. According to a large number of experimental results, the quantitative calculational equation of strength and elongation are obtained by computer processing.


Cheng X.,Jiangsu University | Zhang Y.,Jiangsu University | Li D.,Jiangsu University | Han M.,Jiangsu Yinhuan Precision Steel Tube Co. | And 3 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2015

Microstructure of CHDG-A06 alloy and S30432 stainless steel sensitized at 650 ℃ was analyzed by optical microscope (OM), X ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Meanwhile, intergranular corrosion susceptibility of the two steels was evaluated by intergranular corrosion test. The results show that M23C6 carbides which mainly refer to Cr23C6 carbide precipitate obviously along the grain boundary of S30432 stainless steel after sensitized for 2 h, while little Cr23C6 carbide can be observed along the grain boundary of CHDG-A06 alloy sensitized even for 3 h. The intergranular corrosion susceptibility of CHDG-A06 alloy is lower than that of S30432 stainless steel, and the mechanical properties meet the requirements of ASME, which turns out that the novel CHDG-A06 alloy is more excellent than S30432 stainless steel used as boiler pipes. ©, 2015, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.


Cheng X.,Jiangsu University | Chen M.,Jiangsu University | Li D.,Jiangsu University | Zheng Q.,Jiangsu University | And 4 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2015

Creep property of a novel Fe-Ni based Cr19Ni28TiN alloy was investigated by means of RDL100 high temperature electrical creep machine, OM, SEM and TEM. The results show that the steady-state creep stage can be significantly observed when the loading stress decreased to 250 MPa. Microstructure observation revealed that a few precipitations distribute uniformly in austenite matrix before creep, and after creeping at 600℃ under 300 MPa, a lot of fine TiN and M23C6 precipitations are formed in the grain boundary and inside. The intragranular precipitation impedes the movement of dislocation by pinning dislocation. Meanwhile, a large number of dislocation pile up and produce dislocation wall near the coherent grain boundary. As a result, the creep resistance of Cr19Ni28TiN alloy is remarkably enhanced. The creep fracture analysis shows that the fracture of the Cr19Ni28TiN alloy is even, with some shallow tearing dimple. The secondary precipitations in the pits act the initial core of crack. ©, 2015, Chinese Mechanical Engineering Society of Heat Treatment. All right reserved.


Cheng X.,Jiangsu University | Luo R.,Jiangsu University | Li D.,Jiangsu University | Dai Q.,Jiangsu University | And 5 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2015

The microstructure and properties of the welded joint were studied based on the tungsten argon arc welding of 2 mm thick alloy 800H. The characteristics of microstructure, mico-hardness, room-temperature and high-temperature tensile strength, fractography and intergranular corrosion of samples were analyzed. Results show that the crystallizing morphology on the weld seam is of columnar crystals and equiaxed grains, the grains of heat-affected zone (HAZ) grows bigger, and a small amount of TiN and (Fe,Cr)23C6 phases precipitate in the welded joint. The average hardness of base metal, HAZ and welding seam is 1730, 1526 and 1590 MPa, respectively. Moreover, room temperature tensile strength and elongation for alloy 800H is 565.0 MPa and 31.8%, respectively, which are both higher than the ASME standard requirement (tensile strength 450.0 MPa and elongation 30.0%), and ductile fracture happens at room temperature. The high temperature (650℃) tensile strength and elongation of alloy 800H welding joints is 394.5 MPa and 15.5%, respectively, and the fracture is mixed mode at 650℃. In comparison with welded joint of alloy 800H, the corrosion of base metal are much severer, with intercrystalline fracture of base metal and a few corrosion pits on the surface. The TiN precipitates in the base metal could result in pitting. © 2015, Science Press. All right reserved.


Li D.,Jiangsu University | Li D.-S.,Jiangsu University | Dai Q.-X.,Jiangsu University | Cheng X.-N.,Jiangsu University | And 3 more authors.
Jinshu Rechuli/Heat Treatment of Metals | Year: 2010

Microstructure of the finished Super304H austenitic stainless steel pipe and the perforated 133 mm raw pipe was analyzed. A lot of worm-like phase and niobium compounds were observed in the finished pipe, but little in the raw pipe. The worm-like phase was determined as δ-ferrite by XRD. The analysis results show that the δ-ferrite in finished Super304H pipe generates in the course of heat treatment within the process of 133 mm raw pipe to finished pipe because of the too high treating temperatures. So the solution temperature and softening temperature should be reduced respectively which not only can decrease δ-ferrite but also refine niobium compounds, and ensure the quality of finished pipes and increase the percentage of pass.

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