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| Macro- and Microstructure Evolution of 5CrNiMo Steel Ingots during Electroslag Remelting Process |
| Lei RAO1,Jian-hua ZHAO1,Zhan-xi ZHAO1,Gang DING2,Mao-peng GENG3 |
1. College of Mechanical and Electronic Engineering, Hohai University, Changzhou 213022, Jiangsu, China
2. Xinya Special Steel Forging Co., Ltd., Danyang 212322, Jiangsu, China
3. College of Mechanical and Electronic Engineering, Nanchang University, Nanchang 330031, Jiangxi, China |
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Abstract A comprehensive mathematical model was established and used to simulate the macro- and microstructure evolution during the production process of 5CrNiMo steel ingot by electroslag remelting (ESR) method. Along the ingot height, the macrostructure distribution characteristics changed from vertical, fine columnar grains to tilted, coarse columnar grains, and this transformation process occurred at the very beginning of ESR. In the cross section of the ingot, there were three grain morphology regions and two grain type transition regions from the outside to the center of the ingot. These regions were the fine columnar grain region, columnar competitive growth transition region, coarse columnar grain region, columnar to equiaxed grain transition (CET) region, and coarse equiaxed grain region. The influence of the remelting rate on the macrostructure and microstructure was investigated using a series of experiments and simulations. The results showed that a low remelting rate could produce a small grain growth angle (GGA); the average secondary dendrite arm spacing (SDAS) firstly decreased and then increased as the remelting rate increased. An excessively high or low remelting rate can increase the GGA and average SDAS in ingots. Thus, the remelting rate should be controlled within a suitable range to reduce composition microsegregation and microshrinkage in the ingot to produce an ESR ingot with satisfactory hot forging performance.
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Received: 12 July 2013
Published: 08 July 2014
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| Fund:National Outstanding Youth Science Foundation of China |
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Corresponding Authors:
Rao Lei
E-mail: rao_lei@163.com
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2014, Vol. 21 
