Interface bonding mechanism and heat treatment of the composite roll manufactured by electroslag remelting cladding method
Interface bonding mechanism and heat treatment of the composite roll manufactured by electroslag remelting cladding method
复制标题
电渣重熔熔覆法复合轧辊的界面结合机理及热处理
DOI：
10.1016/j.jmrt.2022.06.072
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发表时间：
2022-06
期刊：
影响因子：
--
通讯作者：
Junwei Dong
中科院分区：
文献类型：
--
作者：
Zhiwen Hou;Yanwu Dong;Zhouhua Jiang;Lev Medovar;Ganna Stovpchenko;Tao Zou;Jun Huang;Xinwei Wang;Junwei Dong
采用电渣重熔熔覆技术(ESRC)制备了Cr5/42CrMo和45/45复合轧辊。结合晶粒和枝晶的生长规律，揭示了界面结合机制。熔覆层的枝晶在部分熔化的晶粒上开始外延生长，熔覆层的晶界沿辊芯部分熔化的晶向生长，保证了熔覆层与辊芯之间可靠的冶金结合。热处理包括正火、退火、淬火和回火工艺。在退火过程中，由于活性差异，C原子从低C含量的辊芯扩散到高C含量的包层，从而在轧辊芯侧形成了铁素体区域。在淬火过程中，C原子从包层向辊芯扩散，铁素体区域消失，保证了连续的显微硬度。界面两侧元素含量的梯度导致了组织和性能的显著差异。热处理后，从包层到辊芯，组织由马氏体+碳化物转变为珠光体+铁素体。相应地，覆层和辊芯的洛氏硬度(HRC)分别达到53.6和25.7，抗拉强度(Mpa)分别达到1657和879，冲击韧性(J/cm2)达到5~54。复合轧辊具有高硬度的覆层和高冲击韧性的辊芯，可满足热连轧支承辊的要求。
The Cr5/42CrMo and 45/45 composite rolls had been produced by the electroslag remelting cladding (ESRC) method. The interface bonding mechanism was revealed according to grain and dendrite growth. The dendrites of cladding started an epitaxial growth on the partially melted grains and the grains boundaries of cladding grew following the orientation of the partially melted grains of the roll core, ensuring reliable metallurgical bonding between the cladding and the roll core. The heat treatment included the normalizing, annealing, quenching, and tempering process. During the annealing process, the ferrite zone formed on the roll core side because the C atoms diffused from the roll core of low C content to the cladding of high C content for the activity difference. During the quenching process, C atoms diffused from the cladding to the roll core, and the ferrite zone disappeared which ensured the continuous microhardness. The gradient of elements contents on both sides of the interface led to the distinctive difference in microstructure and properties. After the heat treatment, from the cladding to the roll core, the microstructures changed from martensite + carbides to pearlite + ferrite. Accordingly, the values of the Rockwell hardness (HRC) 53.6 and 25.7, the tensile strength (MPa) 1657 and 879, and the impact toughness (J/cm 2 ) 5 to 54 were achieved in the cladding and roll core, respectively. The composite rolls had the cladding of high hardness and roll core of superior impact toughness that could satisfy the requirement for backup rolls of hot strip mills.