Since the dawn of mankind, metalworking has assured strength, toughness, reliability, and the highest quality in a variety of products. Today, these advantages of forged components assume greater importance as operating temperatures, loads, and stresses increase.

Forged components make possible designs that accommodate the highest loads and stresses. Recent advances in forging technology have greatly increased the range of properties available in forgings.

Economically, forged products are attractive because of their inherent superior reliability, improved tolerance capabilities, and the higher efficiency with which forgings can be machined and further processed by automated methods.

The degree of structural reliability achieved in a forging is unexcelled by any other metalworking process. There are no internal gas pockets or voids that could cause unexpected failure under stress or impact. Often, the forging process assists in improving chemical segregation of the forging stock by moving centerline material to various locations throughout the forging.

To the designer, the structural integrity of forgings means safety factors based on material that will respond predictably to its environment without costly special processing to correct for internal defects.

To the production employee, the structural reliability of forgings means reduced inspection requirements, uniform response to heat treatment, and consistent machinability, all contributing to faster production rates and lower costs.

Directional Strength is Key Directional strength is a direct result of the forging process. In the forging process, controlled deformation (usually at elevated temperatures) results in greater metallurgical soundness and improved mechanical properties of the material. In most cases, forging stock has been pre-worked to remove porosity resulting from the solidification process. This produces directional alignment (or "grain flow") for important directional properties in strength, ductility, and resistance to impact and fatigue.These properties are deliberately oriented in directions requiring maximum strength. Working the material achieves recrystallization and grain refinement that yields the maximum strength potential of the material with the minimum property variation, piece-to-peace. Properly developed grain flow in forgings closely follows the outline of the component. In contrast, bar stock and plate have unidirectional grain flow; any changes in contour will cut flow lines, exposing grain ends, and render the material more liable to fatigue and more sensitive to stress corrosion.

Designers and materials engineers are recognizing the increasing importance of resistance to impact and fatigue as a portion of total component reliability. With the use of proper materials and heat treatments, if required, improved impact strength of forged components is achievable.

The resulting higher strength-to-weight ratio can be used to reduce section thickness in part designs without jeopardizing performance characteristics of safety. Weight reduction, even in parts produced from less expensive materials, can amount to a considerable cost savings over the life of a product run.

The consistency of material from one forging to the next, and between separate quantities of forgings is extremely high. Forged parts are made through a controlled sequence of production steps rather than random flow of material into the desired shape.

Uniformity of composition and structure piece-to-piece, lot-to-lot, assure reproducible response to heat treatment, minimum variation in machinability, and consistent property levels of finished parts.

Dimensional characteristics are remarkably stable. Successive forgings are produced from the same die impression, and because die impressions exert control over all contours of the forged part, the possibility of transfer distortion is eliminated.

For cryogenic applications, forgings have the necessary toughness, high strength-to-weight ratios, and freedom from ductile-brittle transition problems.

Forgings are produced economically in an extremely broad range of sizes. With the increased use of special punching, piercing, shearing, trimming, and coining operations, there have been substantial increases in the range of economical forging shapes and the feasibility of improved precision. However, parts with small holes, internal passages, re-entrant pockets, and severe draft limitations usually require more elaborate forging tooling and more complex processing, and are therefore usually more economical in larger sizes.

Sizing Up the Competition

Forging versus	Forging Advantages When Using A Similar Alloy
Casting	Stronger  Preworking refines defects More reliable, lower cost over component life Better response to heat treatment  Adaptable to demand
Welding/Fabricating	Material savings, production economies Stronger Cost-effective design/inspection  More consistent and better metallurgical properties  Simplified production
Machining	Broader size range of desired material grades Grain flow provides higher strength More economical use of material  Yields lower scrap Requires fewer secondary operations
Powder metal	Stronger Higher integrity  Requires fewer secondary operations Greater design flexibility Less costly materials
Composites/Plastics	Less costly materials Greater productivity Established documentation Broader service-temperature range More reliable service performance

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

Metal	Characteristic	Application
Aluminum	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.
Magnesium	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, Brass, Bronze	Well-suited to forging Electrical and thermal conductivity	Important for applications requiring corrosion resistance.
Low-Carbon and Low-Alloy Steels	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 Steels	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 trunio
Special-Alloy Steels	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	Corrosion-resistant	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	Creep-rupture strength Oxidation resistance	Service in the 1,200-1,800°F range. Structural shapes, turbine components, and fittings and valves.
Titanium	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	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.
Beryllium	Light, hard, and brittle Increasingly used as an alloying material High melting point Special forging techniques have been developed to process beryllium in sintered, ingot, or powdered form	Used primarily in nuclear, structural, and heat-sink applications.
Zirconium	Corrosion-resistant	Produced in relatively limited quantities and used almost exclusively in nuclear applications.

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Since the dawn of mankind, metalworking has assured strength, toughness, reliability, and the highest quality in a variety of products. Today, these advantages of forged components assume greater importance as operating temperatures, loads, and stresses increase.

Forged components make possible designs that accommodate the highest loads and stresses. Recent advances in forging technology have greatly increased the range of properties available in forgings.

Economically, forged products are attractive because of their inherent superior reliability, improved tolerance capabilities, and the higher efficiency with which forgings can be machined and further processed by automated methods.

The degree of structural reliability achieved in a forging is unexcelled by any other metalworking process. There are no internal gas pockets or voids that could cause unexpected failure under stress or impact. Often, the forging process assists in improving chemical segregation of the forging stock by moving centerline material to various locations throughout the forging.

To the designer, the structural integrity of forgings means safety factors based on material that will respond predictably to its environment without costly special processing to correct for internal defects.

To the production employee, the structural reliability of forgings means reduced inspection requirements, uniform response to heat treatment, and consistent machinability, all contributing to faster production rates and lower costs.

Directional Strength is Key Directional strength is a direct result of the forging process. In the forging process, controlled deformation (usually at elevated temperatures) results in greater metallurgical soundness and improved mechanical properties of the material. In most cases, forging stock has been pre-worked to remove porosity resulting from the solidification process. This produces directional alignment (or "grain flow") for important directional properties in strength, ductility, and resistance to impact and fatigue.These properties are deliberately oriented in directions requiring maximum strength. Working the material achieves recrystallization and grain refinement that yields the maximum strength potential of the material with the minimum property variation, piece-to-peace. Properly developed grain flow in forgings closely follows the outline of the component. In contrast, bar stock and plate have unidirectional grain flow; any changes in contour will cut flow lines, exposing grain ends, and render the material more liable to fatigue and more sensitive to stress corrosion.

Designers and materials engineers are recognizing the increasing importance of resistance to impact and fatigue as a portion of total component reliability. With the use of proper materials and heat treatments, if required, improved impact strength of forged components is achievable.

The resulting higher strength-to-weight ratio can be used to reduce section thickness in part designs without jeopardizing performance characteristics of safety. Weight reduction, even in parts produced from less expensive materials, can amount to a considerable cost savings over the life of a product run.

The consistency of material from one forging to the next, and between separate quantities of forgings is extremely high. Forged parts are made through a controlled sequence of production steps rather than random flow of material into the desired shape.

Uniformity of composition and structure piece-to-piece, lot-to-lot, assure reproducible response to heat treatment, minimum variation in machinability, and consistent property levels of finished parts.

Dimensional characteristics are remarkably stable. Successive forgings are produced from the same die impression, and because die impressions exert control over all contours of the forged part, the possibility of transfer distortion is eliminated.

For cryogenic applications, forgings have the necessary toughness, high strength-to-weight ratios, and freedom from ductile-brittle transition problems.

Forgings are produced economically in an extremely broad range of sizes. With the increased use of special punching, piercing, shearing, trimming, and coining operations, there have been substantial increases in the range of economical forging shapes and the feasibility of improved precision. However, parts with small holes, internal passages, re-entrant pockets, and severe draft limitations usually require more elaborate forging tooling and more complex processing, and are therefore usually more economical in larger sizes.

Sizing Up the Competition

Forging versus	Forging Advantages When Using A Similar Alloy
Casting	Stronger  Preworking refines defects More reliable, lower cost over component life Better response to heat treatment  Adaptable to demand
Welding/Fabricating	Material savings, production economies Stronger Cost-effective design/inspection  More consistent and better metallurgical properties  Simplified production
Machining	Broader size range of desired material grades Grain flow provides higher strength More economical use of material  Yields lower scrap Requires fewer secondary operations
Powder metal	Stronger Higher integrity  Requires fewer secondary operations Greater design flexibility Less costly materials
Composites/Plastics	Less costly materials Greater productivity Established documentation Broader service-temperature range More reliable service performance

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

Metal	Characteristic	Application
Aluminum	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.
Magnesium	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, Brass, Bronze	Well-suited to forging Electrical and thermal conductivity	Important for applications requiring corrosion resistance.
Low-Carbon and Low-Alloy Steels	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 Steels	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 trunio
Special-Alloy Steels	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	Corrosion-resistant	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	Creep-rupture strength Oxidation resistance	Service in the 1,200-1,800°F range. Structural shapes, turbine components, and fittings and valves.
Titanium	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	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.
Beryllium	Light, hard, and brittle Increasingly used as an alloying material High melting point Special forging techniques have been developed to process beryllium in sintered, ingot, or powdered form	Used primarily in nuclear, structural, and heat-sink applications.
Zirconium	Corrosion-resistant	Produced in relatively limited quantities and used almost exclusively in nuclear applications.

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