What is the difference between castings produced by gravity casting machines and press castings?

Automotive aluminum alloys are widely used in automobile manufacturing, aerospace and other fields due to their good plasticity. Aluminum alloy casting technology is roughly divided into gravity casting and pressure casting. Gravity casting machines and pressure casting machines use these two different casting technologies. Do you know what the difference is between the castings they produce?

The castings produced by press castings have good surface finish and cannot be heat treated. The strength and surface hardness of the castings are high, but the elongation is low, the mold cost is high, and thin-walled parts can be produced, but the processing margin is small. The castings produced by gravity casting machines have fewer internal pores, can be heat treated, have high product elongation, low mold cost, and long mold life.

In fact, when choosing a product production process, it is usually selected based on the wall thickness of the product. When the product wall thickness is thicker, die casting will cause many pores. Therefore, when the product wall thickness is greater than 4mm, a gravity casting machine can be selected for production.

Why do press castings need to be returned for heat treatment?

The tempering heat treatment of press castings is a key part of mechanical manufacturing technology. Compared with other processing technologies, heat treatment generally does not change the shape and overall chemical composition of the workpiece. The chemical composition of the surface of the CNC drilling machine casting is used to give or improve the performance of the workpiece. The characteristics are to improve the intrinsic quality of the CNC drilling machine casting to improve its own performance and improve the intrinsic quality of the bed casting. There are four basic technologies for the overall heat treatment of CNC drilling machine castings, bed columns, CNC drilling machine workbenches, etc. annealing, direct annealing, quenching and tempering.

The tempering of press castings must strictly follow the tempering technology, add support ribs to the parts where the ribs are dense or easily deformed, and prevent deformation and fracture caused by the tempering temperature. The person in charge should monitor the furnace thermometer and control the temperature in time to avoid excessively high or low temperatures, which has a great impact on the tempered workpiece.

Why do press castings need tempering treatment: Steel is a material widely used in the machinery industry. The microstructure of steel is complex and can be controlled by heat treatment. In order to make CNC drilling machine castings have the necessary mechanical properties, physical properties and chemical properties, heat treatment technology is indispensable. In addition, aluminum, copper, magnesium, titanium and their alloys also change their mechanical, physical and chemical properties through heat treatment to obtain different performance. Overall heat treatment is a metal heat treatment technology that heats the cast iron flat plate, cast iron bent plate or CNC drilling machine casting as a whole, and then cools it at an appropriate rate to improve the overall mechanical properties of the CNC drilling machine casting. Therefore, tempering heat treatment of CNC drilling machine castings is very important.