Influence of Cold Rolling Process on Mini Spangle Formation of 55%Al-Zn Alloy Coating Steel Sheet

2018 ◽  
Vol 936 ◽  
pp. 171-177
Author(s):  
Tai Xiong Guo ◽  
Xue Qiang Dong ◽  
Chang Rong Ran
Keyword(s):  
Cold Rolling ◽  
Steel Sheet ◽  
Steel Substrate ◽  
Steel Strip ◽  
Alloy Coating ◽  
Compound Layer ◽  
Rolling Process ◽  
Intermetallic Compound Layer ◽  
Rolling Oil ◽  
Zn Alloy

According to that mini spangle is the most common defect affecting the appearance quality of hot-dip 55%Al-Zn alloy coated steel sheet, industrial experiments and statistical analysis were done to investigate the influence of cold rolling process on the formation of mini spangle. The results show that, with the decrease of rolling oil concentration, the increase of rolling time, and the increase of rolling pass, the probability of mini-spangle formation increases. Due to the different equipment conditions, the probability of mini-spangle formation on the upper and lower surfaces of steel strip is different. The reason of mini-spangle formation lies in the presence of carboxylates (R-COO-Fe) result from the residual emulsion on the surface of cold rolled steel strip. The carboxylates may interfere with the interfacial reaction between the steel substrate and Al-Zn bath, and result in more convex Fe5Si2Al20 phases formed on the surface of intermetallic compound layer. The Fe5Si2Al20 phases may provide more heterogeneous nucleation sites for the formation of Al-rich dendrites and lead to the formation of mini spangle.

scholarly journals Silicon Steel Strip Profile Control Technology for Six-High Cold Rolling Mill with Small Work Roll Radius

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 401
Author(s):  
Hainan He ◽  
Jian Shao ◽  
Xiaochen Wang ◽  
Quan Yang ◽  
Xiawei Feng
Keyword(s):  
Cold Rolling ◽  
Rolling Mill ◽  
Steel Strip ◽  
Work Roll ◽  
Rolling Process ◽  
Silicon Steel ◽  
Cold Rolling Mill ◽  
Strip Profile ◽  
Profile Control ◽  
Small Work

Due to the requirement of magnetic properties of silicon steel sheets, producing high-precision size strips is the main aim of the cold rolling industry. The tapered work roll shifting technique of the six-high cold rolling mill is effective in reducing the difference in transverse thickness of the strip edge, but the effective area is limited, especially for a high crown strip after the hot rolling process. The six-high mill with a small work roll size can produce a strip with higher strength and lower thickness under a smaller rolling load. At the same time, the profile of the strip can be substantially improved. By advancing a well-established analytical method, a series of simulation analyses are conducted to reveal the effectiveness of a small work roll radius for the strip profile in the six-high cold rolling process. Through the analysis of flattening deformation and deflection deformation on the load, the change rule of the strip profile produced by the work roll with a small roll diameter can be obtained. Combined with theoretical analysis and industrial experiments, it can be found that the improvement effect of the small work roll radius on the profile of the silicon strip is as significant.

scholarly journals Investigation and Optimization of Load Distribution for Tandem Cold Steel Strip Rolling Process

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 677 ◽  
Author(s):  
Xin Jin ◽  
Changsheng Li ◽  
Yu Wang ◽  
Xiaogang Li ◽  
Yongguang Xiang ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Cold Rolling ◽  
Prediction Model ◽  
Load Distribution ◽  
Rolling Mill ◽  
Fitness Function ◽  
Steel Strip ◽  
Rolling Process ◽  
Cold Rolling Mill ◽  
Tandem Cold Rolling

In order to improve the cold rolled steel strip flatness, the load distribution of the tandem cold rolling process is subject to investigation and optimization. The strip deformation resistance model is corrected by an artificial neural network that is trained with the actual measured data of 4500 strip coils. Based on the model, a flatness prediction model of strip steel is established in a five-stand tandem cold rolling mill, and the precision of the flatness prediction model is verified by rolling experiment data. To analyze the effect of load distribution on flatness, the flatness of stand 4 is calculated to be 7.4 IU, 10.6 IU, and 16.8 IU under three typical load distribution modes. A genetic algorithm based on the excellent flatness is proposed to optimize the load distribution further. In the genetic algorithm, the classification of flatness of stand 4 calculated by the developed flatness prediction model is taken as the fitness function, with the optimal reduction of 28.6%, 34.6%, 27.3%, and 18.6% proposed for stands 1, 2, 3, and 4, respectively. The optimal solution is applied to a 1740 mm tandem cold rolling mill, which reduce the flatness classification from 10.8 IU to 3.2 IU for a 1-mm thick steel strip.

Fe-Zn Alloy Coating on Galvannealed (GA) Steel Sheet to Improve Product Qualities

2014 ◽  
Vol 23 (9) ◽  
pp. 3336-3346 ◽  
Author(s):  
Debabrata Pradhan ◽  
Akshya Kumar Guin ◽  
Pankaj Raju ◽  
Manindra Manna ◽  
Monojit Dutta ◽  
...  
Keyword(s):  
Steel Sheet ◽  
Alloy Coating ◽  
Improve Product ◽  
Zn Alloy

Influence of Rare Earth on Hot-Dipped 55%Al-Zn Alloy Coating

2013 ◽  
Vol 774-776 ◽  
pp. 1132-1136 ◽  
Author(s):  
Tai Xiong Guo ◽  
Xue Qiang Dong ◽  
Shu Hui Deng ◽  
Feng Li ◽  
Yi Lin Zhou
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Simulation Experiment ◽  
Steel Substrate ◽  
Intermetallic Layer ◽  
Alloy Coating ◽  
Al Alloy ◽  
Zinc Dross ◽  
Zn Alloy ◽  
The Rare Earth

Simulation experiment was done to investigate the effects of rare earth on hot-dipped Zn-55%Al alloy coating. The results show that the rare earth has little effect on the zinc dross and its burning loss is about 10%. The microstructure of coating is similar to that of solidification bath, and which is made up of phases of rich aluminum, rich zinc, rich silicon and rare earth, and intermetallic layer of Al-Zn-Fe-Si. The rare earth phase is needle or rod, and mainly distributed inside rich zinc phase and on the interface between the coating and steel substrate. The rare earth has no obvious influence on coating grain and spangle size. The appropriate addition of rare earth would be helpful to improve the coating bending formability and corrosion resistance.

Prediction of Edge Crack in Cold Rolling of Silicon Steel Strip Based on an Extended Gurson–Tvergaard–Needleman Damage Model

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Quan Sun ◽  
Jianjun Chen ◽  
Hongliang Pan
Keyword(s):  
Cold Rolling ◽  
Edge Crack ◽  
Steel Strip ◽  
Damage Model ◽  
Rolling Process ◽  
Reduction Ratio ◽  
Shear Damage ◽  
Gtn Damage Model ◽  
Edge Cracking ◽  
Roller Radius

Edge cracking is commonly observed in cold rolling process. However, its failure mechanism is far from fully understanding due to the complex stresses and plastic flow conditions of steel strip under the rolling condition. In this paper, an extended Gurson–Tvergaard–Needleman (GTN) damage model coupled with Nahshon–Hutchinson shear damage mechanism was introduced to investigate the damage and fracture behavior of steel strip in cold rolling. The results show that extended GTN damage model is efficient in predicting the occurrence of edge crack in cold rolling, and the prediction is more accurate than that of the original GTN damage model. The edge cracking behavior under various cold rolling process parameters is investigated. It comes to the conclusion that edge crack extension increases with the increase of the reduction ratio, tension and the decrease of the roller radius and friction coefficient. The influence of shear damage becomes more significant in rolling condition with a larger reduction ratio, smaller roller radius, lower friction force, and tension.

Influence of Process Conditions on Spangle Size of 55%Al-Zn Alloy Coated Steel Sheet

2017 ◽  
Vol 889 ◽  
pp. 127-132 ◽  
Author(s):  
Tai Xiong Guo ◽  
Quan Xu ◽  
Chang Rong Ran ◽  
Xue Qiang Dong
Keyword(s):  
Steel Sheet ◽  
Steel Strip ◽  
Injection Pressure ◽  
Bath Temperature ◽  
Dew Point ◽  
Process Conditions ◽  
Coated Steel ◽  
Coated Steel Sheet ◽  
Zn Alloy ◽  
Air Knife

Statistic analyses of industrial experimental datum were done to investigate the effect of pretreatment process, hot-dip process and posttreatment process on spangle size of hot-dip 55%Al-Zn alloy coated steel sheet. The results show that, with the decrease of concentration of degreasing solution, the decrease of RTF dew point temperature, the decrease of temperature at which strip entering into Al-Zn bath, and the increase of injection pressure of air knife, spangle size decreases; with the increase of hydrogen content in RTF, spangle size decreases firstly and then tends to be stable; with the increase of bath temperature, spangle size increases firstly and then decreases; The hot-dip time, the distance between air knife and steel strip, the height of air knife from Al-Zn bath, and the blowing rate of cooling fan have little effect on spangle size; the addition of mixed rare earth doesn’t affect spangle size, while the addition of titanium with trace amount leads to the decrease of spangle size.

Thermal Scratch on Surface of SUS430 Stainless Steel Strip in Cold Rolling Process

2014 ◽  
Vol 21 (3) ◽  
pp. 282-286 ◽  
Author(s):  
Chang-sheng Li ◽  
Jin-shan Chen ◽  
Wen-long Han ◽  
You-yuan Li ◽  
Bo Fu
Keyword(s):  
Stainless Steel ◽  
Cold Rolling ◽  
Steel Strip ◽  
Rolling Process ◽  
Thermal Scratch
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