Dendrite Growth Characteristics and Segregation Control of Bearing Steel Billet with Rotational Electromagnetic Stirring

2017 ◽  
Vol 36 (4) ◽  
pp. 339-346 ◽  
Author(s):  
Yu Xu ◽  
Xiu-Jie Xu ◽  
Zhuang Li ◽  
Tao Wang ◽  
An-Yuan Deng ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Solidification Process ◽  
Bearing Steel ◽  
Dendrite Growth ◽  
Growth Characteristics ◽  
Electromagnetic Stirring ◽  
Secondary Dendrite Arm Spacing ◽  
Steel Billet ◽  
Dendrite Fragmentation ◽  
Equiaxed Grain

AbstractThe effects of rotational electromagnetic stirring (R-EMS) on dendrite growth characteristics and segregation control of bearing steel billet were investigated in continuous casting. The results show that applying R-EMS can promote columnar-equiaxed transition, increase the region of the equiaxed grain from 5 % to 45 %, decrease the secondary dendrite arm spacing (SDAS), and reduce the segregation of both carbon and sulfur. Meanwhile, the fragments of dendrite arms induced by R-EMS are observed. The length of the dendrite fragmentation is approximately 1.5 mm, 7–10 times the SDAS. Some fragments can partially remelt to become effective nuclei, and some fragments survive the solidification process.

Optimization for Secondary Cooling Parameters in Continuous Casting of High Carbon Chromium Bearing Steel

2009 ◽  
Vol 83-86 ◽  
pp. 465-472
Author(s):  
Wei Chen ◽  
Yu Zhu Zhang ◽  
Li Guang Zhu ◽  
C.J. Zhang ◽  
Bao Xiang Wang
Keyword(s):  
Continuous Casting ◽  
Calculated Data ◽  
Minimum Cost ◽  
Solidification Process ◽  
Element Model ◽  
Bearing Steel ◽  
Cooling Zone ◽  
Secondary Cooling ◽  
High Carbon ◽  
Key Factor

The high carbon chromium bearing steel, as a kind of special steel, entails high quality. The work aims to simulate the solidification process of continuous casting of high carbon chromium bearing steel, to find the cause for defect, and to optimize the secondary cooling parameters steel. A finite element model is developed to compute heat transfer and solidification in bearing continuous casting. By comparing the calculated data with the metallurgical constraints, the key factor caused the cracks on the strand can be found out. Then based on the subproblem approximation method, an optimization program is developed to search out the optimum cooling parameters. Those optimum parameters can meet all specified requirements but with a minimum expense of the operational and the design constraints and can make it possible to run the caster at its maximum productivity, minimum cost and to reduce the defects. Now, online verifying has been obtained with the cracks decreasing and the water consumption of secondary cooling zone saving.

High-efficiency continuous casting of GCr15 bearing steel bloom based on cooperative control technique of complex electromagnetic stirring and soft reduction

2019 ◽  
Vol 116 (6) ◽  
pp. 621 ◽  
Author(s):  
Hanghang An ◽  
Yan Ping Bao ◽  
Min Wang ◽  
Quan Yang ◽  
Xiang Hong Wang ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Casting Speed ◽  
Bearing Steel ◽  
Average Degree ◽  
Electromagnetic Stirring ◽  
Control Technique ◽  
Internal Quality ◽  
Soft Reduction ◽  
Carbon Segregation ◽  
Gcr15 Bearing Steel

GCr15 bearing steel exhibits comparatively serious center macro-segregation in the continuous casting of bloom with the increase of casting speed. In the present work, the influence of complex electromagnetic stirring (M + F-EMS) and mechanical soft reduction (MSR) on the center macro-segregation in the continuous casting of 220 × 260 mm blooms of GCr15 bearing steel have been comparatively investigated to increase casting speed in order to ensure a good internal quality. Based on numerical simulation and experiments, M + F-EMS and MSR have been comprehensively evaluated and compared by combination of industrial trials. The results show that center carbon segregation first decreases and then increases with the increase of casting speed in both processes without optimization. For M + F-EMS process, when casting speed increases from 0.75 to 0.85 m · min−1, the average degree of center carbon segregation decreases from 1.2 ∼ 1.26 to 1.18 ∼ 1.25 by asymmetrical optimization; with regard to combination of M + F-EMS and MSR process, when casting speed increases from 0.75 to 0.9 m · min−1, the average degree of center carbon segregation decreases from 1.2 ∼ 1.26 to 1.08 ∼ 1.1 and the solute element distribution becomes homogeneous by optimization. In comparison, significant reduction of the center macro-segregation with the increase of casting speed can be achieved for combination of M + F-EMS and MSR process, however, it is infeasible for M + F-EMS process in the present technology situation.

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