New Application: Impeller Blade Casting

MES Inc. was proud to deliver, this past quarter, a one of a kind impeller blade castings for axial fans. Material was carefully chosen by the customer because of excellent strength properties at elevated temperatures.

Are you interested in learning more about impeller casting? Contact us today to secure an expert consultation!

Aluminum C355:

• Offers excellent castability, pressure tightness and resistance to hot cracking.
• Has optimal fluidity and solidification shrinkage tendencies.
• Allows for excellent welding strengths (although in the specific case of this application did not allow any welding.)

Polished finishes can be worthy of excellent engineered components which customers appreciate. These blades were designed and manufactured for axial fans with end application in underground and above-ground mining and power industries.

Material was cast using high vacuum melting casting furnace and high tilt automatic equipment. All parts were then X-ray tested per ASTM E155 with expectation to meet Level 2 near the shank of the blade and Level 4 in other areas. Parts also went through machining with tight tolerance of +/-0.02” expected near the shank of the blade. Parts were required to be heat treated (Tempered T-6) level to ensure heat characteristics. However, part twist geometry was seen to be deforming so parts were quenched after casting.

Post quenching, a reshaping operation was added using special fixture to bend the part to desired tolerance. Tempering was then after reshaping. Reshaping, quenching and base machining were done to ensure part twist characteristics were intact and tolerance requirements were met.

C355.0 can be sand cast or permanent cast. Typical sand casting applications include printing press bedplates, air compressor pistons, water jackets, crankcases, electric motor fans and blowers. Permanent mold castings are developed for aircraft, missile, and other components requiring high strength, and for fittings, impellers, timing gears and aircraft supercharger covers. Automotive applications for this aluminum grade include: passenger car wheels, engine blocks, cylinder heads, spring brackets, transmission cases, and miscellaneous truck and trailer castings.

Application Specifics:

• Material – C355 with T6 heat treatment
• Cast Weight – 52 Lbs
• Post-Machining Weight – 47 Lbs
• Overall Length – 32.5”
• Blade Length – 30.6”
• Porosity Requirements – Level-2 X-ray requirements with some areas allowed at Level-4
• No distortions allowed along the trailing edge
• Proper filling of the OD of Shank area
• Meeting Elongation requirement of 8% on such a long part while meeting T6 mechanical properties

The impellers inside your centrifugal pump may look very similar, but their performance differs due to their design. Besides the number of impellers stacked in a pump, the width of the impeller, the number, angle, and thickness of the vanes inside the impeller all play a role in performance.

 

There are 3 basic types of pump impellers:

 

Radial Flow indicates that water exits the impeller perpendicular to the inlet and these are used to build pressure in lower volume pumps, say under 100 GPM.

 

Axial Flow impellers indicate that water exits the impeller somewhat parallel to the inlet and these are used for high volume low pressure.

 

Mixed Flow impellers exit water at an angle between perpendicular and parallel to create a flow between 120 GPM and 5000 GPM.

Contact us to discuss your requirements of stainless steel pump casting. Our experienced sales team can help you identify the options that best suit your needs.

Additional reading:
Advantages and Applications of Permanent Magnet Screw Compressor
How Does the Mud Mixer Work?
Where can I find hydrocyclone desanders for sale?

 

The objective then is to design an impeller that can create pressure in a desired range of flow. How does an impeller achieve a certain performance? Let’s look at the basics using the radial flow as an example.

 

On a radial flow impeller, the inlet, or eye, of the impeller diameter must be large enough to pass the volume of water needed. Yet small enough for water to be acted on by vanes after it enters the impeller. The width of the impeller between the shrouds also provides a given volume that, when rotating at 3450 or 1725 RPM, will empty and fill to create the given volume. The number of vanes inside the impeller, usually 5 to 8, also control the volume by creating more time to fill and empty the cavity.

 

Pressure is controlled by diameter and speed at which the impeller rotates as well reacting to the resistance in the system to which the pump discharges. The pressure is determined by calculating the velocity in feet per second that a point on the circumference of the impeller turns, then by converting the velocity units to pressure.

 

Finally, creating flow and pressure within the pump is a way of adding energy to the liquid being pumped. This energy is what makes the liquid flow and it has pressure added to it. To do this, the impeller needs energy from a source. This energy is referred to as horsepower required. So, the more we add flow and pressure energy to the impeller design, we also require greater horsepower to rotate it.

 

When the impeller is produced, it has a performance curve that goes from the maximum amount of water that can pass through it with no pressure, down to no flow and maximum pressure. The appropriate size impeller is then selected for installation in a pump requiring this specific performance.

 

The Webtrol WS Series submersible well pumps use stainless steel impellers as shown in the image.

 

 

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For more stainless steel grinder body castinginformation, please contact us. We will provide professional answers.