Forgings are superior to metal parts produced by other methods in their compatibility with other manufacturing processes
The characteristically uniform refinement of crystalline structure in forged components assures superior response to all forms of heat treatment, maximum possible development of desired properties, and unequaled uniformity. Because forged components of weldable materials have a near absence of structural defects, material at welding surfaces offers the best possible opportunity for strong, efficient welds by any welding technique. Again, the near absence of internal discontinuities or surface inclusions in forgings provides a dependable machining base for metal-cutting processes such as turning, milling, drilling, boring, broaching, and shear spinning; and shaping processes such as electrochemical machining, chemical milling, electrical-discharge machining, and plasma jet techniques. Forged parts are readily fabricated by assembling processes such as welding, bolting, or riveting. More importantly, single-piece forgings can often be designed to eliminate the need for assemblies. In many applications, forgings are ready for use without surface conditioning or machining. Forged surfaces are suited to plating, polishing, painting, or treatment with decorative or protective coatings.
Forging Spans the Metallurgical Spectrum
Aluminum Forging Design Considerations
- Readily forged
- Combines low density with good strength-to-weight ratio
- Primarily for structural and engine applications in the aircraft and transportation industries where temperatures do not exceed 400°F.
- Offer the lowest density of any commercial metal
- Usually employed at service temperatures lower than 500°F but certain alloys provide short-time service to 700°F.
Copper, Bronze & Brass Forgings
- Well-suited to forging
- Electrical and thermal conductivity
- Important for applications requiring corrosion resistance.
Low-Carbon and Low-Alloy Steel Forgings
- Low material cost
- Easily processed
- Good mechanical properties
- Varied response to heat treatment gives designers a choice of properties in the finished forging
- Comprise the greatest volume of forgings produced for service applications up to 900°F.
Microalloy / HSLA Steel Forgings
- Low material cost
- Cost benefit derived from simplified thermomechanical treatment
- Equivalent mechanical properties to many carbon and low-alloy steels
- Various automotive and truck applications including crankshafts, connecting rods, yokes, pistons, suspension and steering components, spindles, hubs, and trunions.
Special-Alloy Steel Forgings
- Permit forgings with more than 300,000 psi yield strength at room temperature
- Used in transportation, mining, industrial and agricultural equipment, as well as high-stress applications in missiles and aircraft.
Stainless Steel Forgings
- Used in pressure vessels, steam turbines, and many other applications in the chemical, food processing, petroleum, and hospital services industries. Used for high-stress service at temperatures up to 1,250°F and low-stress service to 1,800°F and higher. Nickel-Base.
Nickel-Base Superalloy Forgings
- Creep-rupture strength
- Oxidation resistance
- Service in the 1,200-1,800°F range. Structural shapes, turbine components, and fittings and valves.
- High strength
- Low density
- Excellent corrosion resistance
- Alloys offer yield strengths in the 120,000 to 180,000 psi range at room temperatures
- Used primarily in the temperature services to 1,000°F. Configurations nearly identical to steel parts are forgeable and 40% lighter in weight. Aircraft-engine components and structurals, ship components, and valves and fittings in transportation and chemical industries.
Refractory Metal Forgings
- Include columbium, molybdenum, tantalum, and tungsten and their alloys
- Enhanced resistance to creep in high-thermal environments
- High-temperature applications involving advanced chemical, electrical, and nuclear propulsion systems and flight vehicles.
- Produced in relatively limited quantities and used almost exclusively in nuclear applications.
Why Forgings are Best