6.Sand Pumps Casting Quenching
Quenching is a heat treatment process in which a casting is heated to a suitable temperature for a period of time and then rapidly cooled by immersing it in a quenching medium. Commonly quenching media are brine, water, mineral oil, air and so on. Quenching can increase the hardness and wear resistance of metal work pieces. Through quenching and tempering at different temperatures, can greatly improve the strength, toughness and fatigue strength of the casting, and also can obtain the cooperation between these properties (comprehensive mechanical properties) to meet different application requirements.
After heating the sand pumps casting to a certain temperature, put it in a prepared cold water container and quickly cool it immediately. After the surface temperature of the casting is lowered to room temperature, removed it from the cold water container, placed in the casting area, and awaits the next finishing process.
The hardness of the casting is increased after quenching, which increases the wear resistance of the casting.
(1)Pump Body Processing:
The sand pumps processing equipment mainly includes lathes, vertical lathes, and boring machines. The sand pumps body is machined in vertical and boring machines, and clamped on the work surface.
Use horn to correct the position of the flow channel, which is convenient for compaction. The boring table can be rotated to machine multiple sides in one setup.
Impeller processing mainly work on a lathe. Use four-jaw clamp the impeller outer diameter, take the center of the runner or the front and rear cover flow channels as the axial alignment reference and the impeller inlet diameter for clamping after radial alignment. Rough wheel impeller inlet port ring fine car balance 1-2 mm; Drill the balance holes of the impeller, ensure the size and evenly divide the blade spacing, and not damage the blades. Finally perform the balance test.
The center hole must be repaired for the heat-treated shaft. Hold both ends to Semi-finishing, fine car allowance 0.5-1 mm, and complete the machining of the thread on the shaft, retracting groove, etc. Pay attention to avoid stress concentration due to sharp corners and influence the strength of the shaft; for the less demanding parts, can use lathe carrier, then refinishing the outer circle. If the mating surface requires high precision and mass production of the shaft, Abrasive wear allowance 0.3-0.6 mm; Milling key way, pay attention to ensure symmetry; grinding the outer circle, Use two tops of lathe carrier to grind the mating surface.