In the process of operation of the pump valve castings, the basic characteristics of high-density molding sand are mainly that the clay content is high, the moisture is low, and the addition amount of pulverized coal is also low. Therefore, you should take good care of the measurement when you use the sand.
Mud content and clay content of pump valve castings
In the process of making the pump valve casting, the sand with high clay content will increase with the specific pressure during the operation process. Normally, the effective bentonite will be controlled at 7% to 10%. The sum of effective clay and dead clay in sand is equivalent to mud content, and the mud content is generally controlled at 12% to 16%. Mud content is too high or too low will affect the sand performance indicators.
Water in pump valve castings
The water in the manufacturing sand of pump valve castings is to a certain extent the main factor that determines the plasticity and bonding force of the clay. When the water is too high during the operation, it will easily cause the clay adhesion to deteriorate directly. The sand has a reduced fluidity and a uniform mold density cannot be obtained. When the water content is too low, the sand cannot be easily mixed, the sand is low in strength, the brittleness is large, and the moldability is poor, which easily causes the sand casting defects of the casting. The general moisture should be controlled at 10% to 20% higher than the moisture at the peak of the wet compress strength.
Original sand size of pump valve castings
When the high density molding is used, the density of the sand is high, and the expansion during casting is large. Therefore, the original sand particle size should not be excessively concentrated. The original sand particles are round or polygonal. Generally, three or four screen sands are selected.
Pump valve casting reinforcement method
Pump valve casting reinforcement method, in the process of operation, under normal circumstances can effectively add a small amount of carbon in the raw materials, in the determination of the wall thickness of its valve castings, it should also be appropriate to add manganese, manganese content should be About 4%. The alloying method is used to increase the tensile strength of gray iron castings, and appropriate amount of trace alloys are added. Chrome, molybdenum, tin and other elements can also significantly improve the tensile strength of gray iron castings, and do a good job in the treatment of hot metal.http://www.pump-casting.com/