一种薄壁球铁阀门铸造工艺的改进

Improvement of Casting Process for a Thin-walled Ductile Iron Valve

一种具有复杂内腔的薄壁压缩机阀门类球铁铸件,重量为3.4 kg,主要壁厚为4 mm,有容易产生冷隔、断芯和气孔类缺陷,产品铸件对外观质量和气密性要求高,为此在设计浇注系统时采用了碳化硅泡沫过滤块。因铸件结构复杂、热节多而分散,需要在合理的位置设计出有效的冒口进行补缩,以保证铸件的内部质量,确保铸件的气密性。设计初步的铸造工艺方案并进行生产验证,发现铸件上表面容易产生冷隔、气孔和断芯等缺陷,导致铸件废品率很高。因此对铸造工艺进行了改进,解决了铸件缺陷,并最终达成批量稳定供货。

A kind of thin-walled ductile iron castings of compressor valves with complex inner cavities.The casting weight is 3.4 kg,and the main wall thickness is 4 mm.It is very easy to produce cold shut,broken core and porosity defects.The product castings have high requirements for appearance quality and air tightness.Therefore,silicon carbide foam filter blocks need to be used when designing the gating system.Due to the complex structure and scattered hot spots of the casting,it is necessary to design effective risers at reasonable positions for feeding to ensure the internal quality of the casting and the airtightness of the casting.Design a preliminary casting process plan and conduct production verification,and it was found that the upper surface of the casting is prone to defects such as cold shuts,pores,and broken cores,resulting in a high scrap rate of the casting.Therefore,improvements were made to the casting process,ultimately completely resolving casting defects and ultimately forming a stable supply in bulk.