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在离心铸造厚壁大型钢套时,在涂料中引入稀土合金及碱金属盐复合变质剂,可减小钢套外层凝固所需的过冷度、细化晶粒、控制碳化物单一方向生长,解决凝固过程中热传导瓶颈问题,避免热裂纹产生。根据路易斯酸碱理论,从化学角度对以铈为主的稀土合金变质机理进行探讨。并对钢套硫含量控制水平进行界定。亚纳米稀土颗粒引入极大增加异质形核衬底数,进一步减小钢套外层凝固的过冷度,同时也改善了涂料的悬浮性。钢套凝固后,溃落的涂层可回用,实现绿色铸造。
In the centrifugal casting of large-scale thick-walled steel casing, the introduction of rare earth alloy coating and alkali metal salt compound modifier, can reduce the outer layer of steel sleeve solidification required for the degree of supercooling, grain refinement, carbide growth control in one direction , Solve the problem of heat conduction bottleneck in the solidification process and avoid the generation of hot cracks. According to Lewis acid-base theory, the mechanism of cerium-based rare earth alloy modification is discussed from the chemical point of view. And define the control level of steel sleeve sulfur content. The introduction of sub-nano rare earth particles greatly increases the heterogeneous nucleation substrate number, further reducing the supercooling degree of the steel sleeve outer solidification, and also improves the suspension of the paint. After the steel sleeve solidified, the collapsed coating can be recycled to achieve green casting.