What Is Forging?
Forging is a method of shaping metal through compressive force like rolling, pressing, or hammering using a die or hammer. A cast ingot or cogged billet is compressed between dies after being heated to high-temperature plasticity. Common materials used for forged mining parts include everything from soft metals like aluminum, copper, or brass to harder metals like stainless steel, carbon steel, or alloy steel.
The metal is deformed to impart additional strength and fatigue resistance qualities before being formed into geometric shapes. Metal forgings suppliers offering forging services categorize mining forgings as warm, hot, or cold forging, named for the temperature used during the manufacturing process.
The resulting forged mining parts reflect specific mechanical properties as required by the application. Forging lends itself well to mass production, producing minimal waste.
Advantages of Forging
Industrial forging provide many advantages, particularly to the needs of the mining industry. A variety of sizes, shapes, and volumes can be accommodated along the full metallurgical spectrum when manufacturing custom forgings, from prototypes to production parts.
Mining forgings are built to operate in some of the harshest environments where strength and reliability are key to both productivity and safety. Two of the most significant advantages of closed die forging are the manufactured components grain flow and strength.
When forging manufacturing mining parts they are imparted with a uniform grain flow by heating the metal under controlled conditions. Grain flow increases fatigue resistance and improves toughness and ductility.
Forged mining parts offer superior integrity. Pre-working improves directional strength by removing the ingot’s porosity and refining the dendritic structure. The forging process removes gas pockets and voids and more evenly disperses alloys for improved structural strength and chemical uniformity. Superior structural integrity and impact strength reduce weight and sectional thickness while ensuring the components perform reliably under field-load conditions.
Machining is often performed after forging to improve dimensional accuracy. Post-forging sizing and coining may also be used. The lack of voids and porosity in forged products allow them to be machined after forging with no loss of quality.
Forged parts are finished at near-net-shape by our American forging company, reducing machining time and improving capacity. Forging tools and dies are relatively low cost, even in smaller quantities. The near-zero waste due to the recyclability of flash further saves on the overall cost.
Common Types of Forged Mining Parts
The most challenging applications and severe conditions are found in the mining industry. It necessitates components that can withstand extreme circumstances. Forged mining parts play a vital role, providing reliable strength and performance for mining trucks, crushers, draglines, shovels, excavators, motor graders, wheel loaders, and more. Mining forgings enable tools and equipment for a variety of applications.
Drills create access for extracting metal and minerals from rocks and soil, from entry points for miners to channels where explosives can be set. Crushers must withstand continuous pressure to reduce large materials into smaller proportions, such as gravel, small stones, or sand. Above the ground, earthmovers are essential to remove discarded materials in massive quantities to allow deeper access. Common components include:
- Auger, chipper, and chisel bits
- Block cutters
- Consumable bits and teeth
- Earthmover wheel lugs
- End plates
- Front and rear spindles and frames
- Grinder tips
- Hammerhead inserts
- Large hydraulic cylinders
- Main shafts for crusher applications
- Parts for draglines and rope shovels
- Pick blocks
- Raker forgings
- Rock tools
- Seamless rolled rings, center hubs, doughnuts, rims, sleeves, bull gears, gear blanks, and pancake forgings
- Side straps
- Tooth holders and inserts
Closed Die Forging Process
Closed die or impression die forging is a manufacturing process where the metal is placed in a die attached to an anvil. A hammer drops onto the die in rapid succession, forcing the heated metal into the contours of the die. Any excess metal is forced out of the die and forms flash. The flash cools quickly and is removed after forging.
The closed die forging process is executed in stages where the metal is moved through the die cavities. The first impression molds the metal into a rough shape, known as edging impression, fullering, or bending. The blocking cavities allow the metal to take on more of the final shape, introducing bends and fillets. The final impression cavity is the last stage that enables the forged part to be finished and detailed to the required specs.
There are several advantages of closed die forging. They can produce massive parts up to 25 tons. It is also economical for heavy production. It produces next to no waste, as the flash is recyclable. The final product is nearly exact, requiring minimal finishing.
Though forging is a relatively quick process, the entire forging timeline incorporates the many prerequisite procurement and tooling creation steps and any specific finishing and inspection procedures. The typical timeline is as follows:
- Raw material procurement – One to three weeks
- Tooling creation – Two to three weeks
- Product development and testing – One to two weeks
- Forging – One to three days
- Shot blast cleaning – One day
- Heat treat – One to two weeks
- Shot blast cleaning – One day
- Coining/piercing – One to two days
- Final inspection – One day
- Shipping and transit – One day
Additional post forging processes add to the overall timeline. Per client needs, they may include one or more of the following:
- Coating process – One to three weeks
- Blanchard grinding – One to two weeks
- Machining – One to three weeks
- Non-destructive testing – One week
- Pull testing – One week
- Roll marking – One to two weeks
Forging vs. Casting
Forging is vastly different than casting. One distinct difference is that hot or warm forging heats the metal to a level of plasticity but does not melt the metal. Another is that compressive forces are used to form the part in forging, where casting involves pouring the molten metal into a mold to create the desired shape. Forging is used for mining and many other heavy-duty applications due to its superior strength, offering higher tensile strength, fatigue strength, and ductility than cast parts.
Forged steel also has superior yield strength over cast iron. Yield strength determines the maximum load before deformation. Melting a metal changes the grain structure by allowing some grains to expand, leading to a random grain structure that results in decreased strength. Since forging allows the metal to remain in a solid state, the grain structure remains tight, consistent, and mechanically strong.
Considerations that determine forging vs. casting include finished product size, design, type of alloy used, internal strength requirements, and price. Since forging uses compression force to form the part, as the size increases, so do the forces necessary, meaning there is a practical limit to the size of a forged product.
Forged products exhibit design complexity and accommodate various steel alloys with the added benefits of strength, low porosity, and structural integrity. Though casting may be less expensive, it can be at the cost of longevity, reliability, safety, and productivity.
Forgings Suppliers in the US
Trenton Forging is one of the premier metal forging companies in the U.S. We forge steel, steel alloys, and stainless using gravity-drop style hammers, air-lift, and closed-impression dies. Our custom steel forgings ensure optimal strength, product integrity, grain structure, and longevity. From parts as small as .01 pounds to as large as 15 pounds, we produce a lighter, stronger, and more cost-effective product.