Casting Process and Material Capabilities

As a full-service provider of casting and precision machining, Impro Aerospace has a variety of capabilities to ensure that we can meet the complex needs of our customers in industries such as aerospace, medical, and energy.

Casting Process Capabilities

Our various casting capabilities enable us to produce parts of varied complexity in size and volume. Some of the processes we use include:

Investment Casting

This method of metal casting involves making a wax pattern-which is a replica of the final piece – building shell mold around the wax pattern, and then pouring molten metal and knocking out the shell materials after the metal has solidified.

At Impro Aerospace, we use air, vacuum and air pressurization methods to ensure that all mold cavities are filled and that each detail is imprinted onto the workpiece. We can handle weights from 1 ounce up to 100 pounds (0.03 to 45 kilograms) and sizes up to 1,000 mm. Our typical surface finish is Ra 3.2, though we can achieve Ra 2.8 upon request.

Permanent Mold Casting

In place of wax molds, this process uses a metal mold to cast a metal product. Since the mold is permanent, permanent mold casting is often the most cost-effective casting method for high-volume production or repeatable production runs. The initial cost of the mold can be fairly high, but the durability of the mold enables economies of scale that eventually offset these costs over time. Given this high upfront cost, the tooling costs of this process are often much too prohibitive for small and medium runs.

Impro Aerospace can create permanent molds for parts up to 33 pounds (15 kilograms) and sizes up to 400 mm, and our process produces a surface finish of Ra 6.4. We pour molten metal using gravity/counter-gravity methods, which is well-known for its ability to create defect-free parts.

Shell Mold Casting

Casting with a shell mold involves creating any number of thin and temporary sand-resin molds. Each individual mold can then be filled with molten metal to cast the end product, making the process both scalable and intricate. Once the molten metal is cooled, the shell mold is easily broken away to free the shell cast part.

Shell molds can be used to cast highly detailed parts or parts with very complex features. Ben
efits include low labor and tooling costs, low scrap generation, and a high rate of production. While the process itself is affordable, the equipment required to create the molds is relatively expensive.

Impro Aerospace can shell mold parts up to 33 pounds (15 kg) at sizes up to 300 mm. Our shell molding process creates a surface finish of Ra 12.5, and our gravity/counter-gravity pouring method ensures a high level of detail with little risk of part defects.

Superalloys

Also known as high-performance alloys, superalloys exhibit a range of favorable qualities. Trademark characteristics include strength and stability as well as resistance to corrosion and heat. Impro Aerospace offers a wide variety of superalloys, each uniquely suited for the needs of different industries including:

• Inconel (625, 713, 718, 738)
• FSX-414
• F75
• MARM-247
• And more

Inconel, a superalloy of nickel and chromium, boasts high tensile strength in situations of extreme heat. Another benefit is its high corrosion resistance, which also stems from this oxide formation.
There are several varieties of Inconel, each optimized for use in different contexts:

• • Inconel 625 resists corrosion from salt and chloride, making it ideal for use in saltwater or chemical processing applications.
  • Inconel 713 provides additional thermal fatigue protection and excellent rupture strength. It is most appropriate for aerospace applications, such as jet engines.
  • Inconel 718 blends together the qualities of 625 and 713 into one corrosion-resistant material that features high strength independent of temperature. Since it resists both corrosion and heat damage, 718 works in many of the same industries as the previous two superalloys, including aquatic and aerospace settings, and is additionally suited for nuclear reactor components.
  • Inconel 738 offers superior creep rupture strength at high heats and provides unprecedented corrosion resistance, which allows for use in almost any environment.

  FSX-414 and F75 are cobalt-based superalloys best suited for use in special machining. Much like Inconel 713, FSX-414’s heat-resistant properties make it apt for use in engine construction, power plants, or other high-heat situations. F75, on the other hand, blends cobalt and cadmium to offer high hardness that allows for shiny, durable surfaces.

  Lastly, MARM-247 is a nickel-based superalloy that can withstand severe physical stress. Because it responds better to physical rather than chemical damage, it is a good option for applications that require high surface stability and are less exposed to corrosion or oxidation.

  Aluminum

  In contrast to the above superalloys, which are more rare and expensive casting options, aluminum is the world’s most abundant metal, making it simple and cheap to work with. Aluminum still holds a variety of important benefits, including:

  • Rust resistance
  • Heat resistance
  • High ductility

  These properties make it ideal for moist environments where rust may otherwise pose a problem, such as sewage plants, and hot environments where excessive smelting may damage equipment, such as manufacturing. Impro Aerospace offers many aluminum options, such as:

  • A356
  • C355
  • F357
  • And more

  Stainless Steel

  One of the most popular choices for direct-to-consumer applications, stainless steel also has many benefits in industrial environments. By combining the powers of low carbon steel and chromium alloys, stainless steel offers corrosion and oxidation resistance by forming a chromium oxide film, much like Inconel. This chemical resistance makes it an ideal choice for applications where sanitation is important, such as medicine, food manufacturing, and agricultural equipment.

  Stainless steel can be austenitic or martensitic. The main difference is that austenitic steel offers high chemical resistance while martensitic steel boasts impressive physical strength. Additionally, austenitic steel reaches its full potential in heat-intensive environments, while martensitic is best for less extreme applications. Here at Impro Aerospace, our stainless steel casting options include both types.

  • Martensitic stainless steel: 410 and more
  • Austenitic stainless steel: 304, 304L, 347, 316, 316L and more
  • Precipitation hardening stainless steel: 17-4PH, 15-5PH and more
  • Other materials as per customer requirements

  Low Alloy Steel

  Unlike stainless steel, low alloy steel focuses on mechanical strength and resistance. By incorporating 1-5% of another alloy like nickel, chromium, or manganese, low alloy steels combine the physical toughness of plain steel with the additional chemical and physical properties offered by the chosen alloy. High alloy steel has the same composition but includes more of the designated alloy, incorporating upwards of 10% of the other material. This exceptional mechanical strength lends itself to applications in automotive and aerospace projects, where products must maintain high levels of stability.

  Impro Aerospace offers the following low alloy steels:

  • IC4140
  • IC8620
  • 16MnCr5
  • 42CrMo4
  • And more

  Casting Services at Impro Aerospace

  Impro Aerospace is proud to offer a flexible, diverse range of casting solutions that will uniquely address your needs. Whether you are looking for physical stability, chemical durability, or a combination of both, our team will work with you to find the perfect metals and methods for your industry. To learn more about our available casting processes and materials, reach out to us today.