Surface cleaning method for stainless steel investment castings

Manipulation skills for stainless steel precision casting:

The blank is made into the required electrode, and then the electrode is used to flush the mold to form a cavity. The original wax pattern is obtained by casting wax using a casting technique. Apply a layer of high-temperature resistant liquid sand wax mold. After obtaining sufficient thickness, it is dried, and then heated to melt the surface wax mold into a cavity consistent with the desired blank. The mold cavity is then poured with molten iron, and after solidification, the shell is peeled off to obtain a finished product.

Surface cleaning techniques for stainless steel precision castings:

1. Dry cleaning

Strictly speaking, dry cleaning includes conflict cleaning and shot blasting cleaning. However, due to the surplus in cleaning and poor cleaning effect, stainless steel precision castings are currently rarely accepted. The so-called dry method is common shot blasting cleaning. Jet cleaning refers to using compressed air as the power to radiate to the surface of a workpiece at a speed of about 50 m/s to remove adhering sand or iron oxide from its surface. Shot blasting is relatively naive and a reliable addition to shot blasting cleaning. Shot blasting is a kind of equipment on various special machines, such as roller, hook type, chain type, trolley type, etc., used for steel shot blasting and surface cleaning. The difference between shot peening and shot blasting of initial shot steel and the difference in kinetic energy of initial shot steel.

The surface cleaning of domestic precision casting products mainly involves shot blasting technology. With the development of shot blasting technology, in addition to cleaning castings, it is also applied to platforms such as surface strengthening of metal parts, rust removal of steel, and shot blasting molding.

2. Wet cleaning

1) Electrohydraulic sand cleaning. The root cause is the electrohydraulic hammer effect, which causes the high-voltage pulse generator to discharge between special electrodes placed in water, resulting in a large hydraulic blow. Because the surface adhesion of precision casting products is different from the elastic modulus and vibration frequency of the casting itself, the purpose of sand cleaning is achieved. For castings with complex shapes such as deep holes, blind holes, and cavities, there are reliable cleaning results.

2) Hydroblasting. It refers to a technique of using high-pressure water input from a high-pressure water pump to form a high-pressure jet through the nozzle of the spray gun, and then shooting it at the molding sand and sand core on the surface of the casting to remove sand. Mainly suitable for surface sand and core cleaning of large iron castings.

3) Clear sand with water. The partial bearing pedestal is a precision casting product with sand at a temperature sensitive to temperature. The water entering the water tank and the hot sand mold and sand core is heated and evaporated. As the water evaporates and the steam is continuously heated, the pressure increases, and the sand mold and sand core are scattered from the surface and inner cavity of the casting, thereby achieving the goal of sand cleaning.

Precautions for stainless steel precision casting processing:

1. Clear all obstructions in the passageway and garden.

2. Check whether the molten iron ladle is dry, and whether the ladle bottom, ladle ears, ladle bars, and end handles are reliable. Rotate the surface of the ladle to ensure that it cannot be inspected with an undeveloped molten iron ladle.

All objects in contact with molten iron should be preheated to above 500 ℃ before use, otherwise they cannot be used.

4. "The amount of molten iron shall not exceed 80% of the total amount of molten iron, and the lifting of the ladle shall be carried safely and slowly, with consistent steps to prevent injury caused by the splashing of molten iron.".

5. Before lifting molten iron with a crane, it is necessary to check whether the hooks and chains are reliable. During lifting, the chains must not be knotted, and special personnel should be assigned to follow the molten iron package. There should be no idle personnel passing through the route.

6. Strictly implement the "six non pouring" principle for precision castings:

(1) Do not pour if the temperature of molten iron is insufficient;

(2) The trademark of molten iron is not poured due to negligence;

(3) No slag blocking or pouring;

(4) Do not pour the sand box until it is dry;

(5) Do not pour without placing an external gate;

(6) Do not pour if there is not enough molten iron.