Inside Delta Centrifugal
What Makes a Great Metal Alloy?
Welcome to our plant! Centrifugal Casting is a multi-step process from selecting the best formula heated to the exact temperature, poured into the most suitable mold all the way to using up-to-date technique in machining your product.
See How Delta Does It
At Delta Centrifugal, quality assurance starts with step one and continues through shipping. Click on a thumbnail below to see this process in a foundry and machine shop dedicated to giving our customers the highest quality metal alloys.
What is Centrifugal Casting?
The centrifugal casting process is one in which molten metal is poured into a rapidly rotating mold. While this may seem simple, many factors must be monitored and precisely controlled for the process to be successful. While the chemical composition of the material must fall within the parameters of the specification, knowing exactly where within those limits helps differentiate the experienced centrifugal foundry. Temperatures of the metal and mold along with rotation speeds and the flow rate of the pour combine with clockwork precision in the production of the highest quality centrifugal castings.
A centrifugally cast product produces less waste and requires fewer production hours since less machining is necessary. The metal is of superior quality because it is free of porosity and contains almost none of the inclusions found in metals produced using other methods.
Step 1: Mold Lining
Molds are uniformly preheated and lined with a refractory mold wash
(white surface) to insulate the mold from the molten alloy that will follow. The lining process is subject to precise controls akin to the metal pour itself.
Step 2: Molten Metal Poured
The molten alloy is poured into the rapidly spinning mold at a monitored and controlled rate. The rotation of the mold is calculated to subject the casting to tremendous g-forces which are proprietary for the particular size and alloy characteristics. These forces serve to both shape and physically refine the casting into a dense, high quality tubular product.
Step 3: Casting Extraction
Upon cooling below transition range, the solidified casting is removed from the mold.
It is immediately hot metal stamped with the alloy type, heat number, and job number.
Step 4: Cleaning and Inspection
After cooling, just before the casting is shot-blasted to remove the remaining mold lining material, the casting is inspected visually and dimensionally to assure the standard of quality our customers deserve.
Step 5: Mold Inventory
The mold is then either re-lined for subsequent casting production or inspected and returned to inventory for future use. Delta maintains an inventory of over 350 molds giving us the capacity to produce centrifugal castings that meet a wide range of sizes.
Quality control does not stop when the mold stops spinning. Exact heat treatment is critical to the finished metal product. Our heat treating facility is state of the art and unrivaled in our industry. Our furnaces are certified to +/-10 degrees in compliance with aerospace, petrochemical and nuclear requirements.
Step 1: Castings are Loaded into the Furnace
Cleaned castings are loaded into the car bottomed furnace and the door is hydraulically closed to begin the heat treat cycle. Castings are held for the specified time and temperature necessary for optimum results for each alloy.
Step 2: Mold Lining
Upon heat cycle completion, the door is opened to begin the next crucial phase of a proper heat treatment.
Step 3: Removal From Furnace
The castings are then removed from the furnace and transferred to the appropriate air, water or polymer quench in compliance with the specification. Since cooling at the proper rate is just as important as the proper heating to a quality centrifugal casting, Delta Centrifugal completes heat treatment of each alloy with the appropriate quench.
As a full-service, foundry and machine shop, Delta Centrifugal is equipped to cut any centrifugal castings within our current alloy casting capabilities ranging up to 36 inch diameter. To insure that the finished product is of the desired quality, we employ both abrasive wheel and water-jet technologies as required by the specifications and alloy which is being cut.
Step 1: Preparation for Cutting
To assure each project’s accurate completion, castings are matched with their job routing traveler (blue document inside the tube). The document specifies the lengths needed as well as all subsequent steps of manufacture required to deliver the quality metal product our customers require.
Step 2: Material is Cut to the Required Length
A highly productive abrasive wheel cutting technology is employed for most centrifugal casting cuts.
Step 3: Material Transfer
Centrifugal castings which have been precisely cut into proper lengths are transferred to the next operation.
Extensive CNC Machine Capability
The ability to deliver finished-machined products makes Delta a complete production facility. Close tolerance CNC machines, honing, milling, deep hole boring, surface overlaying and our new “Waterjet” cutting technology work together to produce precision centrifugal casting products that our customers have grown to expect.
Changing the Industrial World
At Delta Centrifugal, centrifugal casting, heat treating, and cutting technologies combine to produce the most complex finished—machined components to meet the industrial world’s rapidly changing needs.
Delta has added a computer controlled waterjet system to its inventory of services, to meet the growing need for precision milling. This system cuts metal alloys without added friction, thus protecting the integrity dimensionally. The cut is made more quickly and more smoothly thereby saving us time and our customers money.
We use the unmatched versatility of a waterjet to expand our capabilities beyond what is possible with lasers, EDM or mills.
This computer-controlled machine can cut parts to specifications from material 1/16 to 8 inches thick with minimal waste.