| 铸钢的熔点较高，钢液易氧化 |
| 添加时间：2019/9/19 14:28:26 浏览次数： |
| 铸钢的熔点较高，钢液易氧化、钢水的流动性差、收缩性大，其体收缩率为10～14%，线收缩为1.8～2.5%。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，必须采取较为复杂的工艺措施： Cast steel has high melting point, easy oxidation of molten steel, poor fluidity of molten steel and large shrinkage. Its volume shrinkage rate is 10-14%, and linear shrinkage is 1.8-2.5%. In order to prevent defects such as insufficient pouring, cold isolation, shrinkage and porosity, cracks and sand sticking in steel castings, more complicated technological measures must be taken. 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；浇注系统的结构力求简单；采用干铸型或热铸型；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。但是浇温过高，会引起晶粒粗大、热裂、气孔和粘砂等缺陷。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℃；大型、厚壁铸件的浇注温度比其熔点高出100℃左右。 1. Due to the poor fluidity of molten steel, in order to prevent cold insulation and insufficient pouring, the wall thickness of steel castings should not be less than 8 mm; the structure of the pouring system should be simple; dry or hot casting models should be adopted; the pouring temperature should be properly increased, generally from 1520 to 1600 because of the high pouring temperature, the superheat of molten steel is high and the liquid state should be maintained. Over time, liquidity can be improved. However, too high pouring temperature will cause defects such as coarse grain, hot cracking, pore and sticky sand. Therefore, the pouring temperature of small, thin-walled and complex castings is about steel melting point temperature + 150 C, and that of large and thick-walled castings is about 100 C higher than its melting point. |
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