Z.Yang
,
P.K.Seo
,
C.G.Kang
材料科学技术（英文）
To investigate the possibility of substituting the mechanical stirring system with electromagnetic stirring (EMS) system for aluminum rheo die-casting, the EMS under the different stirring cooling conditions was carried out. It was found that in the early period of solidification, the dendrite breakages led to a fine primary phase. When dendrites grew coarsely, the effect of ripening on grain size overwhelmed that of dendrite breakage. It was also found that the high cooling rate favored large nucleation rate, and led to a fine primary phase. But high cooling rate also made the growth rate of the dendrite arm, which prevented the dendrite arm from being sheared off. Therefore there were a suitable stirring time and suitable cooling rate to obtain the best rheo die-casting structure. Qualified semisolid A356 aluminum alloy was successfully manufactured with short time EMS.
关键词:
Semisolid metal process
,
null
,
null
,
null
Weimin MAO
,
Aimin ZHAO
,
Dong YUN
,
Leping ZHANG
,
Yonglin KANG
材料科学技术（英文）
The nondendritic semi-solid slurry preparation of 60Si2Mn spring steel has been studied in this paper. The experiments have shown that when stirred for 2 min on the test condition, the semi-solid slurry with 50%~60% fraction solid and spherical primary austenitic grains in the size of 100~300 μm can be obtained and is easy to be discharged from the bottom little hole of the stirring chamber. The nondendritic slurry of 60Si2Mn spring steel can be rolled into given plate form successfully, but the solid phase and liquid phase is easy to be separated in rolling process so that the solid primary austenite is concentrated in the center and the liquid is near the edge of the rolled plate. The rupture strength and elongation of the plate rolled only once with semi-solid slurry are lower than that of the traditionally repeated hot-rolled plate of 60Si2Mn spring steel.
关键词:
60Si2Mn
,
null
,
null
,
null
Peng ZHANG
,
Yunhui DU
,
Hanwu LIU
,
Daben ZENG
,
Jianzhong CUI
,
Limin BA
材料科学技术（英文）
The electromagnetic-mechanical stirring technology was used to prepare QTi3.5-15/graghite slurry. The distribution of graphite particles in QTi3.5-15/graghite slurry was studied using cold quenching method. The results show that solid fraction of QTi3.5-15/graphite slurry increases with the decreasing of stirring temperature. There is a linear relationship between solid fraction and stirring temperature. With the increasing of solid fraction, the distribution of graphite particles in slurry becomes uniform gradually. When the solid fraction is larger than 45%, the rising of graphite particles in slurry can be restricted, and QTi3.5-15/graghite slurry with uniform distribution of graphite particles can be prepared.
关键词:
null
,
null
,
null
