Deep-sea oil engineering assembly is operating in the deep sea. It should not only bear the pressure and corrosion of sea water for a long time, but also bear the impact of low temperature sea water. Therefore, the core equipment of deep-sea oil engineering platform is required to have high pressure resistance, high corrosion resistance, impact resistance and low temperature resistance. The material of the sand mold casting of the built-in wheel hub developed by our company is 0T400-18AL, the gross weight is 750kg, the maximum wall thickness is 160mm, and the minimum thickness is 20mm. The tensile strength of the 40mm attached test block is ≥ 400 MPa; Yield strength ≥ 240MPa: elongation 18%: – 20C low temperature impact average value ≥ 12) (single value not less than 9]) spheroidization rate 90%: ultrasonic testing of sand castings according to EN12680-3/2003-Level3; Magnetic particle testing shall be conducted for sand castings according to EN1369-3/1997-Level3.
In view of the special requirements for sand castings working in the deep sea environment. The research focuses on the control of the composition and temperature of molten iron, spheroidization and inoculation treatment in the sand casting process design and smelting process. The technology of molten iron filtration and ceramic pipe runner are mainly used in the process design. In smelting, multiple inoculation and slag removal are mainly used to ensure the purity of molten iron, improve the morphology and distribution of graphite, and greatly improve the comprehensive properties of sand castings. By controlling the strength of the sand mold and designing the structure of the sand box, combined with the cold iron process, favorable conditions have been created for the non-riser casting. Through testing, all performance indexes of sand castings meet the requirements of the standard and fully meet the working conditions of sand castings in the deep sea environment.