Domestic turbocharger parts casting production technology status
Domestic turbocharger parts casting production technology status
The turbine housing material is ductile iron (high nickel austenitic, ferritic ductile iron). The casting process is usually a vanishing mould process, a wet sand process or a resin self-hardening sand process.
The turbine housing is a key component of the turbocharger and the shape of its air duct significantly affects the energy efficiency and exhaust gas treatment effect. According to its structural characteristics and taking into account the cost and quality requirements, disappearing mould casting is one of its production processes. The key to vanishing mould casting of turbine housings is the manufacture of the foam mould. Due to its complex shape and air channel shape, it is difficult to guarantee the quality of the foaming mould using the traditional wooden mould casting process; using NC (Numerical control) machining and EDM machining is long and costly. For this reason, some manufacturers based on three-dimensional modelling, based on LOM mould (Laminated 0b ject manufacturing, LOM also known as laminated solid casting), the use of transfer coating casting process, to achieve the rapid manufacture of turbo shell foam mould.
At present, the thin-shell ductile iron turbocharger turbine shell casting process uses central parting, for the side of the door is not in a plane is not easy to parting, in the turbocharger parts process analysis using curved lifting tire method, parting using the important flange face down, closed bottom multi-point pouring system; in the three-dimensional model design based on simulation simulation software, select the parameters needed to simulate the establishment of filling solidification process simulation.
In the moulding using conventional furan resin sand process of the foundry; core making using the 3D model design, design and production and use of special core bones close to the sand core, while the air, water and oil cavity sand core using ceramic shot sand (Baozhu sand) plus Pepset resin / curing agent to produce sand core, core bone around the sand layer strength of 1.2MPa or more, and in accordance with the core box has been marked in the location of the special exhaust The cores are then placed in a special venting channel in accordance with the position already marked in the core box.
The melting is mostly carried out in medium frequency furnaces; the spheroidizing and breeding method is used; the pouring temperature is 1360~1390C and the pouring time is 2~3min. turbine shell casting is also carried out using the wet sand high pressure moulding process and the horizontal parting off box moulding process, depending on the product and the technical reserve.
