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Changzhou, China

Qiu J.-Y.,Changzhou textile garment institute | Pan A.-X.,CSR Qishuyan Institute Co.
Zhuzao/Foundry | Year: 2014

Microstructure segmentation of ductile iron material was realized by capture and processing with digital image technology. On the basis of the mathematical morphology, the integrated recognition method was put forward, which includes multiple shape factors such as area, aspect ratio and fractal dimension. The segmentation of pearlite and graphite was effectively achieved, which improve the accuracy and efficiency of ductile iron microstructure quantitative metallography analysis.

The ester-hardened sodium silicate sand technology was adopted to produce qualified, safe and reliable steel castings for localized high-speed electric multiple units (EMU), such as couplers, clamps, etc., which created considerable social and economic benefits. This paper discussed the selection bases of casting technology, raw materials and properties of ester-hardened sodium silicate sand. The application status was presented and the economic benefit was analyzed.

Qiu J.,Changzhou textile garment institute | Pan A.,CSR Qishuyan Institute Co.
Tezhong Zhuzao Ji Youse Hejin/Special Casting and Nonferrous Alloys | Year: 2014

For the low service life, "flesh out", sticky steel failure in seamless three-roll piercing plug in the early stages, three plug trials with different materials were conducted. By determining rational heating parameters and taking reasonable oxidation programs as well as other measures, the new plug material suitable for the working conditions was presented, and the service life of plug was improved to ensure the quality of the steel and increase production efficiency. ©, 2014, Journal Office of Special Casting and Nonferrous Alloys. All right reserved.

Li Y.-H.,Central South University | Li Y.-H.,Hengyang Valin Steel Tube Co. | Zhao Y.-K.,CSR Qishuyan Institute Co. | Wu Y.,Central South University | And 2 more authors.
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2012

Effects of tempering temperature on microstructures and properties of casing tube with ultra-high strength and good toughness were studied by OM, TEM, SEM and mechanical property tests. The results show that complete tempered-sorbite microstructure can be obtained tempered at 580-700°C. After tempering at 580-630°C, the microstructure still keeps the exposure and shape of martensite, which demonstrates that the microstructure is of certain stability. Ferrite recrystallization occurs at 640°C and the microstructure begins to coarsen when the tempering temperature is up to 700°C. Compared with the hot rolled steel, the ductility and toughness of the steel after quenching and tempering are improved greatly. High temperature tempering embrittlement is not found at 580-700°C, and the strength and hardness decrease gradually with the increase of ductility and toughness at elevated tempering temperature. When tempering at 650°C, the optimum matching between strength and toughness can be realized, fine microstructures can be gotten, which satisfies the requirement of V150 well tube steel, and therefore, the optimum tempering temperature is 650°C.

Feng H.-H.,Nanjing Southeast University | Xu C.-D.,Nanjing Southeast University | Wan J.,CSR Qishuyan Institute Co.
Mathematical Problems in Engineering | Year: 2014

The water-lubricated bearings have been paid attention for their advantages to reduce the power loss and temperature rise and increase load capacity at high speed. To fully study the complete dynamic coefficients of two water-lubricated, hydrostatic journal bearings used to support a rigid rotor, a four-degree-of-freedom model considering the translational and tilting motion is presented. The effects of tilting ratio, rotary speed, and eccentricity ratio on the static and dynamic performances of the bearings are investigated. The bulk turbulent Reynolds equation is adopted. The finite difference method and a linear perturbation method are used to calculate the zeroth- and first-order pressure fields to obtain the static and dynamic coefficients. The results suggest that when the tilting ratio is smaller than 0.4 or the eccentricity ratio is smaller than 0.1, the static and dynamic characteristics are relatively insensitive to the tilting and eccentricity ratios; however, for larger tilting or eccentricity ratios, the tilting and eccentric effects should be fully considered. Meanwhile, the rotary speed significantly affects the performance of the hydrostatic, water-lubricated bearings. © 2014 Hui-Hui Feng et al.

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