铸钢的铸造工艺特点
The mechanical properties of cast steel are higher than cast iron, but the casting properties are worse than cast iron.
铸钢的机械性能比铸铁高，但其铸造性能却比铸铁差。
Because
the melting point of cast steel is high, the liquid steel is easy to
oxidized, the fluidity of molten steel is poor, and the shrinkage is
large, the shrinkage rate of the body is 10 ~ 14%, and the linear
shrinkage is 1.8 ~ 2.5%.
因为铸钢的熔点较高，钢液易氧化、钢水的流动性差、收缩大，其体收缩率为10～14%，线收缩为1.8～2.5%。
In
order to prevent defects such as insufficient pouring, cold isolation,
shrinkage and porosity, cracks and sand, etc., more complex process
measures must be taken than cast iron:
为防止铸钢件产生浇不足、冷隔、缩孔和缩松、裂纹及粘砂等缺陷，必须采取比铸铁复杂的工艺措施：
1,
due to the poor fluidity of the liquid steel, in order to prevent the
steel casting cold insulation and insufficient pouring, the wall
thickness of the steel casting can not be less than 8mm;
1、由于钢液的流动性差，为防止铸钢件产生冷隔和浇不足，铸钢件的壁厚不能小于8mm；
The structure of the pouring system is simple, and the section size is larger than that of cast iron.
浇注系统的结构力求简单、且截面尺寸比铸铁的大；
Use dry casting or hot casting;
采用干铸型或热铸型；
Appropriately
increase the pouring temperature, generally 1520° ~ 1600 ° C, because
the pouring temperature is high, the superheat of molten steel is large,
the liquid time is long, and the fluidity can be improved.
适当提高浇注温度，一般为1520°～1600℃，因为浇注温度高，钢水的过热度大、保持液态的时间长，流动性可得到改善。
But too high pouring temperature will cause coarse grain, hot cracking, porosity and sand and other defects.
但是浇温过高，会引起晶粒粗大、热裂、气孔和粘砂等缺陷。
Therefore,
generally small, thin-walled and complex castings, the pouring
temperature is about the melting point temperature of steel +150℃;
因此一般小型、薄壁及形状复杂的铸件，其浇注温度约为钢的熔点温度+150℃；
The pouring temperature of large, thick wall castings is about 100℃ higher than its melting point.
大型、厚壁铸件的浇注温度比其熔点高出100℃左右。
2,
because the shrinkage of cast steel is much more than that of cast
iron, in order to prevent the casting of shrinkage holes, shrinkage
defects, most of the measures such as riser and cold iron and subsidies
are used in the casting process to achieve sequential solidification.
2、由于铸钢的收缩大大超过铸铁，为防止铸件出现缩孔、缩松缺陷，在铸造工艺上大都采用冒口和、冷铁和补贴等措施，以实现顺序凝固。
In
addition, in order to prevent the production of shrinkage holes,
porosity, porosity and cracks, the wall thickness should be uniform,
avoid sharp corners and right Angle structures, add sawdust to the mold
sand, add coke to the core, and use hollow core and oil sand core to
improve the yield and permeability of the sand or core.
