Qianan Iron and Steel Company of Shougang Group

Qianan, China

Qianan Iron and Steel Company of Shougang Group

Qianan, China
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Wang X.-D.,Shougang Institute of Technology | Li F.,Shougang Institute of Technology | Wang Q.-N.,Qianan Iron and Steel Company of Shougang Group | Li B.-H.,Shougang Institute of Technology | Li B.,Qianan Iron and Steel Company of Shougang Group
Kang T'ieh/Iron and Steel | Year: 2013

To realize the high precision control of hot rolled strip, in accordance with the characteristics of finishing train of hot strip mill: crown is controlled in the upper stream stands and flatness is realized in the down stream stands, one set roll contour configuration technology was developed and applied in 1580 mm hot strip mill of Qian'an Iron and Steel Company of Shougang Group. Negative crown contour was employed on work rolls of F1 stand to enhance the alignment during the rolling. CVC (Continuous Variable Crown) with lower thrust force was employed on work rolls from F2 to F4 to carry out the crown control function. Negative crown contour was adopted on work rolls of down stream stands F5 to F7 to control the flatness quality with a combination with the cyclic long stroke work roll shifting for the roll wear dispersing. VCR (Variable Crown Back-up Roll) contour was employed on all back-up rolls of the finishing mill to increase the cross rigidity of roll stack. After this roll contour configuration technology was utilized, strip shape control with a high accuracy of more than 95% and schedule-free rolling within a certain range have been realized, meanwhile the rolling stability and the length of rolling campaign have been improved and increased, respectively.


Wang X.-D.,Shougang Institute of Technology | Li F.,Shougang Institute of Technology | Li B.-H.,Shougang Institute of Technology | Zhang B.-H.,Qianan Iron and Steel Company of Shougang Group | And 2 more authors.
Kang T'ieh/Iron and Steel | Year: 2012

CVC (Continuous Variable Crown) work roll contour technology since its invention was applied in more than 150 hot rolling mills throughout the world for controlling strip shape. However, in actual application, there were uneven wear on rolls or even roll spalling problems because contact pressure concentrations existed between work and back-up rolls when flat or CVC back-up roll was used for configuration with CVC work roll during the rolling. For solving these defects, a pressure-equalizing back-up roll contour with combination of VCR (Variable Crown Back-up Roll) and CVC back-up roll contours was designed and applied on a hot rolling mill. It not only has the feature of VCR back-up roll contour, but also can improve the contact condition between work and back-up roll. After the application of pressure-equalizing back-up roll contour, roll spalling problem was solved, and strip profile quality was also improved.


Wang X.,Shougang Institute of Technology | Li F.,Shougang Institute of Technology | Zhao L.,Qian An Iron and Steel Company of Shougang Group | Li M.,Qian An Iron and Steel Company of Shougang Group | And 5 more authors.
Proceedings of the 10th International Conference on Steel Rolling | Year: 2010

Shape quality, as one of important indices strictly required by users of hot rolled high strength steel strip, has an important influence on the efficiency of slitting and welding processes and even on the final production quality. Serious shape defects may result to retarding production, damaging processing equipment and even injuring. Steel strip will undergo non-uniform thermal, mechanical and microslructural coupling behaviors which will result lo residual stress in strip during ils rolling and cooling processes. Based on the shape features of high strength steel strip, not only the optimization works for improving shape quality during strip rolling were made, but also four kinds of trial processing routines for eliminating residual stress including slow cooling, roller levelling, temper rolling and heat treatment were designed and carried out. Slitting tests on steel sheet for measuring shape quality were carried out after trial work. The optimum processing routine was determined according to the results of experiments as follows: (1) improving shape quality during rolling through optimizing strip shape control model; (2)controlling strip crown and difference cooling rates on top and bottom surfaces of strip during run-out table cooling for reducing cross bow defects; (3)slight center wave rolling strategy is applied to compensate the flatness change to wavy edges during run-out table cooling; (4) alter cooling down, temper rolling is made on high strength steel strips, and then they are recoiled and taken batch annealing to eliminate residual stress thoroughly; (5) in the end, coils are cut lo sheet by roller leveler machine. Through applying this processing routine, the steel sheels can meet the customers' tight shape quality requirement that both cross bow and flatness, camber are less than 2 mm/m and 5 mm/ 12m, respectively.


Zhang Y.,Shougang Institute of Technology | Wan Q.,Shougang Institute of Technology | Jin Y.,Shougang Institute of Technology | Li M.,Qian An Iron and Steel Company of Shougang Group | And 2 more authors.
Proceedings of the 10th International Conference on Steel Rolling | Year: 2010

The 2 nd West-East Gas Pipeline project, which is under construction, is the longest X80 gas pipeline in China, even in the world. One of the most remarkable characteristics of 2 nd West-East Gas Pipeline project is that 72 percent of X80 pipes applies 18. 4 mm thick X80 hot rolled strip with critical Charpy impact properties for φ1219 mm spiral seam submerged arc-welding pipe with a pressure of 12 MPa from Huoerguosi to Zhongwei, According to the technical specifications of X80 strip and processing characteristics of hot continuous rolling mill, a original product designs for thick wall and high strength and excellent toughness, consisting of strengthening behavior and microstructure control, chemical design and optimized rolling processes, have been developed systematica. Moreover, phase analyses of precipitates ol niobium microalloy at dilierent rolling stages and microstructure evolution during rolling course have been studied, which showed that almost all niobium microalloy have been in the solution during austenization course when reheating temperature have achieved 1180°C, and that about 0. 05% wt. niobium have been precipitated as carbides and nitrides of niobium at subsequent rolling stages and cooling course. Up to now, Shougang have provided 400000 ton 18. 4 mm thickness X80 hot rolled strip for 2 nd line with stable mechnical properties and excellent weldable properties. Mass production statistics show that average yield strength and tensile strength have achieved 590 MPa and 696 MPa respectively, and Charpy impact energy have reached 340J at minus 20 degree.


Wang X.,Shougang Institute of Technology | Li F.,Shougang Institute of Technology | Li B.,Shougang Institute of Technology | Zhu Q.,Shougang Institute of Technology | And 3 more authors.
Proceedings of the 10th International Conference on Steel Rolling | Year: 2010

Within more than one years' production after 2250 mm Hot Strip Mill of Qian'an Iron and Steel Company of Shougang Steel Corporation was commissioned in the end of 2006, roll spalling and broken accidents had happened many times even more seriously on the second stand of roughing mill (R2), and resulted to enormous economical lost. In addition, there was also another issue of lower control precision for strip shape to be solved. Not only for solving the roll spalling and broken problems but also raising the control precision of strip shape, one kind of variable contact back-up roll contour curve (VCR) with a six order of polynomials and negative crown contour were designed and applied respectively on back-up rolls of all mill stands and work rolls of roughing mill stand Rl and R2 instead of conventional flat roll contour. After the application, roll spalling, crown and wedge quality of the transfer bar and strip shape quality were all improved.


Wang X.,Shougang Research Institute of Techonolgy | Li F.,Shougang Research Institute of Techonolgy | Li B.,Shougang Research Institute of Techonolgy | Dong L.,Qianan Iron and Steel Company of Shougang Group | Zhang B.,Qianan Iron and Steel Company of Shougang Group
ISIJ International | Year: 2012

CVC (Continuous Variable Crown) work roll contour technology since its invention has been applied in more than 150 hot rolling mills worldwide for controlling strip shape. However, serious uneven wear on backup rolls and even roll spalling problems can occur due to contact pressure concentrations that exist between work and backup rolls when either cylindrical or CVC backup rolls are configured with CVC work rolls. To prevent these defects, an optimized backup roll contour was designed by combining VCR (Variable Crown Backup Roll) and CVC backup roll contours. This solution features benefits of the VCR design - reducing roll stack deflection and equalizing contact pressure distribution between work and backup rolls - as well as increasing the control capability of work roll bending forces. Implementing the optimized backup roll contour eliminated non-uniform roll wear and spalling, and strip profile was also improved © 2012 ISIJ.

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