先进材料疑固实验室 Mold design Laboratory of Advanced Materials Solidification Two considerations must be made in designing a casting mold, due to the solidification shrinkage: A riser,which is a reservoir of liquid,is needed to compensate for the shrinkage of the whole casting. For every location of a casting,when the liquid solidifies, liquid from the surrounding of that location is needed in order to compensate for the instantaneous shrinkage. 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY
Mold design Two considerations must be made in designing a casting mold, due to the solidification shrinkage: A riser, which is a reservoir of liquid, is needed to compensate for the shrinkage of the whole casting. For every location of a casting, when the liquid solidifies, liquid from the surrounding of that location is needed in order to compensate for the instantaneous shrinkage
先进材料疑固实验室 Solidification Shrinkage Laboratory of Advanced Materials Solidification ⊕ The liquid of most metals and alloys shrinks during solidification. Solidification shrinkage (percent)of some common engineering metals and alloys Aluminum 6.6 Copper 4.9 Magnesium 4.0 Zinc 3.7 Low-carbon steel 2.5-3.0 High-carbon steel 4.0 White cast iron 4.0-5.5 Gray cast iron -1.9 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY
Solidification Shrinkage The liquid of most metals and alloys shrinks during solidification. Solidification shrinkage (percent) of some common engineering metals and alloys
先进材料疑固实验室 Mold design Laboratory of Advanced Materials Solidification Microstructure of the hub section of a Mg alloy casting,showing pores caused by lack of compensation for the solidification shrinkage B0-1 Hub 一 0.1mm 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY
Mold design Microstructure of the hub section of a Mg alloy casting, showing pores caused by lack of compensation for the solidification shrinkage
先进材料疑固实验室 Laboratory of Advanced Materials Solidification Riser Design Risers are added reservoirs designed to compensate for the solidification shrinkage of casting. Riser An Al casting produced without An Al casting produced with a riser using a riser 上游文通大学 SHANGHAI JIAO TONG UNIVERSITY
Riser Design Risers are added reservoirs designed to compensate for the solidification shrinkage of casting. An Al casting produced without using a riser An Al casting produced with a riser Riser
先进材料疑固实验室 Laboratory of Advanced Materials Solidification Riser Design Criteria for riser design: The volume of a riser must be adequate to compensate for all shrinkage volume. Riser must be the last to finish solidification. The liquid flowing channels between the riser and the solidifying metal must be kept open at all times. ry a vanced Matera 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITY
Criteria for riser design: • The volume of a riser must be adequate to compensate for all shrinkage volume. • Riser must be the last to finish solidification. • The liquid flowing channels between the riser and the solidifying metal must be kept open at all times. Riser Design