锡青铜因其糊状结晶特点,难于实现理想的顺序凝固,容易在热节处形成缩松,造成铸件在水压试验时渗漏。采用铁模铸造工艺能在一定程度上弥补这一缺陷,但必须掌握了铁模铸铜的特点,避免铁模铸造的弊病,才能取得更好的效果。一、必须保证顺序凝固与砂型铸件比较,金属型铸件有较高的机械性能,其原因除金属液有较大的冷却速度,使晶粒细化外,还有金属型具有较大的蓄热能力使金属液内外层温差加大,强化了由外向内的顺序结晶。因此,如果配合较好 Tin bronze because of its paste crystallization characteristics, it is difficult to achieve the ideal order of solidification, easy to form shrinkage at the hot section, resulting in casting hydrostatic test leakage. The use of iron mold casting process to a certain extent make up for this shortcoming, but must master the characteristics of iron mold cast iron to avoid the disadvantages of iron mold casting, in order to achieve better results. First, we must ensure that the order of solidification and sand casting, metal casting has a higher mechanical properties, the reason for the addition of molten metal has a greater cooling rate, so that the grain refinement, there are large metal heat storage The ability to increase the temperature difference between the inner and outer layers of molten metal, and strengthen the order from the outside to the crystallization. So if it works well