What are forging?
Forging is a manufacturing process where metal is pressed, pounded, or squeezed under great pressure into high-strength parts known as forgings. Asking the right questions will help you determine who is the right supplier for your company and what forging method can best meet your needs.
Forgings are generally made from alloy steel, stainless steel, or aluminum alloys, but they can also be made from other metal materials. Forging is a manufacturing process that involves heating the metal and shaping it with hammers or presses. This process is often used to make parts for equipment used in agriculture, construction, and machinery industries.
Forging is sometimes confused with casting because both processes involve heating molten metal and shaping it into the desired shape. However, forging uses heavier pressure than casting to shape the metal; this makes forgings stronger than castings because there are fewer weak points where cracks could form.
Forging is a manufacturing process that involves shaping metal by hammering or pressing it into shape. It’s generally done by specialist companies in many different countries and industries, as well as on an individual scale at home.
Types of forging
1. Die forging
Die forging may be a metal forming process. The workpiece is inserted into a die and then hammered until a die shape is formed. The lower die may be a fixed piece, while the upper die may be a moving hammer that falls on the workpiece to deform it. Drop forging is usually performed at high or ambient temperatures. This manufacturing process has a long tradition in the metal forming industry and has been used for many years. The mechanism of the method is still the same, but all the machinery involved has been greatly advanced to show die forging as a high precision manufacturing process. As with all other forging techniques, drop forging improves the fabric properties of the final part.
There are two main tools used in forging presses to deform a blank by means of a large force; for example, a hammer or a press. Drop hammers and presses can produce the same result because the way the force is transferred from the dolly to the metal part is fundamentally different, but the difference is that the dolly affects the workpiece not by continuous pressure, but by continuous hammer blows.
Consistent with the way the hammer is attached and the way it deforms the workpiece, there are different types of dolly hammers: the drop hammer is the simplest forging configuration that can be placed on a specific hammer and anvil, with the lower die fixed to the anvil and the upper (moving) die fixed to the punch, which transfers high speed mechanical energy to the workpiece, placed inside the lower die and the anvil. The anvil structure must provide a very solid base because it absorbs a large amount of energy. As a result, the weight of the anvil is sometimes equal to ten to twenty times the hammer load. The double-acting dolly configuration is comparable to the main dolly, but the dolly fixed to the gate accelerates as the air or steam falls; hydraulic or pneumatic dolly, respectively. Double-acting forging hammers are very powerful and are gradually replacing the simpler configuration, where there is no anvil in the counter-attack forging hammer configuration. However, there are two hammers fixed to two plungers, achieving opposite directions and allowing the workpiece to be shaped precisely.
These are the most important complex forging hammers and they allow achieving very large forging energy levels. As far as the die position is concerned, there are two main types of die forging: open die forging and closed die forging, also known as press die forging.
Open Die Forging
This is also known as Smith forging. In open die forging, a hammer strikes and deforms a workpiece placed on a fixed anvil; it also derives its name from the fact that the die does not surround the workpiece and allows the die to flow outward where it touches, so it must orient and position the workpiece to force it into the specified shape. The mold is flat. However, some have specially shaped surfaces for special processes; for example, the die may have a round, concave or convex surface, or a tool or cutting tool for forming a hole. Open die forging works on cross sections such as discs, hubs, blocks, shafts, sleeves, cylinders, planes, hexagons, circles, plates, etc.
In some cases, open die forging can also be used for rough forming ingots to organize subsequent operations. Open die forging orients the grains to extend the strength in the desired direction. Advantages of open die forging; reduced voids, good fatigue resistance, continuous grain flow, finer grain size, higher strength, better heat treatment response, improved internal quality, higher reliability of mechanical properties, ductility and impact resistance. “Fluting” is the continuous deformation of a bar along its length using an open drop die press. Usually, it is necessary to adjust the thickness of the staple to the right level. Once the correct thickness is achieved, the correct width can be achieved by “edging”. “Edging” is the process of concentrating the material using a concave open die, which is called “grinding” because it is usually distributed at the end of the part. “Full forming” may be a similar process, where convex dies are used to thin the parts of the forging, and these processes prepare the part for further forging processes.
Press Die Forging
Press forging is also known as “closed die forging”. In press die forging, the metal is placed in a mold-like die that is attached to an anvil. Usually, the hammer die is also shaped and dropped on the workpiece, causing the metal to flow and fill the die cavity. The hammer is usually kept millisecond up-to-date with the size of the workpiece, and from the size and complexity of the part, the hammer is also dropped multiple times in rapid succession. The excess metal is squeezed out of the mold cavity, creating what is called “flash”. The flash cools faster than other materials. This cold metal is stronger than the metal in the mold, and the result helps prevent excessive flash while also forcing the metal to completely fill the mold cavity. It is used to distribute the metal into the subsequent cavities of the container shape, called “rim”, “full” or “bend” indentations.
Subsequent cavities are called “blocked” cavities, where the part takes on a shape more similar to the final product. These stages usually give the part a lot of bending and large rounded corners. The final shape is forged in the “final” or “trimmer” cavity. If a shorter part is to be run, the die should not have final gauge clearance; instead, it should be more economical to machine the final features. Due to the recent increase in automation of heating and handling, mechanical feeding, and positioning, embossing die forging has been improved by direct heat treatment of the part after forging. In this type of forging process, the die cavity is completely closed, thus preventing the workpiece from flying edges. The most important advantage of this process is that it minimizes the loss of metal during ignition. The disadvantages of this process, where flying edges account for almost 50% of the starting material, include additional costs due to complex die design and even the need for better lubrication and workpiece placement. In addition, other variants of part forming exist that integrate the stamping and die-forging process. Another method is to pour the forging die with liquid metal.
The casting is removed after solidification, but while still in the hot state. This is then done in a very single-cavity die. The flying edges are cut and then the part is hardened and quenched. The other mode of operation is the same, except that the metal droplets are produced by a jet collector. Closed die forging requires a design process that creates the cavities in a working die and involves high initial costs for the forming die, but becomes economical when performing mass production because of the lower cost per part repeat.
This is often one of the main reasons why the automotive and gear industries often use closed-die forgings. Another reason forgings are common in these industries is that they typically have a 20% higher strength-to-weight ratio compared to cast or machined parts of the same material. Stamped die forgings and die design. Forging dies are usually made of high alloy steel or alloy steel. Dies can be impact and wear resistant, maintain strength at high temperatures, and have the ability to resist rapid heating and cooling cycles; that is, to provide a better, more economical die, the subsequent criteria are maintained: the die part follows a flat surface whenever possible. If not, the parting face follows the part contour, which can be a plane through the middle of the forging and not close to the upper or lower edge, providing sufficient draw slope; usually a minimum angle of 3° for aluminum and 5° to 7° for steel, using a large number of rounded corners and radii, with low and wide ribs. The parts are balanced to avoid metal flow differences and dimensional tolerances cannot be less than necessary. Barreling occurs when, due to friction between the workpiece and the die or punch, the workpiece bulges in its center in some barrel-like manner. Without friction, this ends up in the center part of the workpiece making contact with the perimeter of the die in front of it, thus creating a greater increase in the range of pressures required by the punch to complete the forging. The dimensions contained in the die part have a fairly high degree of accuracy.
2. Press forging
Press forging is placed between dies. It is the process of forming the metal by applying mechanical or hydraulic pressure. Die forging is performed in a forging press, a machine that generates a gradual pressure on the forging die; in addition, the shape of the metal is formed by a stamping stroke that is processed for each die station. The difference between impact forging and pressure forging is that in impact forging, a rapid impact force is applied to the die, but in pressure forging, a gradual increase in pressure is applied to the die. Pressure forging is suitable for the efficiency of forging large volumes of material and is a technique of gradually applying pressure to a die that holds the workpiece in place; the process is suitable for forging in open or closed dies; open die forging is a process in which one side of the metal is surrounded by a die. First, in press and closed-die forging methods, the metal material is fed into the die and then pressure is applied to the die, after which the material undergoes plastic deformation and fills the die cavity. The closed-die method produces less flying edges than open-die forging; in addition, some press-forging methods that use closed dies are casting and wheeling.
The hubs are pressed into the die so that the die flows into the die cavity, a process commonly used in silverware manufacturing.
The three main types of forging presses used for die forging are shown below.
Mechanical presses-Convert the rotation of the motor into a linear motion of the plunger.
Hydraulic presses – The hydraulic movement of the piston moves the plunger.
Screw presses- Screw mechanism drives the plunger movement.
The advantages of forging presses are as follows:; suitable for controlling the compression ratio of the workpiece, economical for mass production, can manufacture most shapes, and produce less scrap.
Upsetting is a manufacturing process in which metal is plastically deformed under high pressure into high-strength parts of various sizes. The forging process is suitable for extended shapes where only one end of the part is to be forged. Upsetting can be manufactured by collecting material into designated areas of carbon, alloy and stainless steel bars. The presses for these parts work on a horizontal plane. The die is split to allow the material to extend beyond the machine, and some forming force is provided by a third die connected to the harvesting table.
4. Roll forging
Roll forging can be a process in which the thickness of a round or flat bar stock is reduced and the length is increased. Roll forging is performed using slotted cylindrical or semi-cylindrical rollers; in addition, a heated bar is inserted into the rollers, which then rotate and gradually form as they roll on the machine.
The workpiece is then transferred to the following set of recesses, or circled out and reinserted into the same recesses until the specified shape and size is achieved. The advantage of this process is the absence of flying edges and the good grain structure of the workpiece. Examples, for this method, include shafts, tapered rods and steel plate springs.
5. Net shape and near net shape forging
This process is also known as precision forging. It was definitely developed to reduce the costs and waste associated with post-forging operations. As a result, the end product of precision forging requires little to no final machining. Cost savings can be achieved by using less material and thus less scrap, less energy use, and thus less or no machining. Precision forging requires less die pulling slope, 1° to 0°. The disadvantage of this process is its cost, so it can only be implemented if significant cost reductions are often achieved. Cold forging near net shape forging is most typical when parts are forged without heating segment plugs, bars or billets. Aluminum can be a common material that is cold forged depending on the final shape. Lubrication of the formed part is essential to extend the life of the mating die.
6. Isothermal forging
Isothermal forging is a thermal process that attempts to observe the workpiece at high temperatures, which can be achieved by heating the die to or slightly below the initial workpiece temperature; in addition, workpiece cooling between the working interfaces of the die is eliminated when the force applied by the die produces the workpiece. As a result, the fluidity of the metal can be significantly improved.
Isothermal forging can be performed in Veryvacum or not. The equipment costs for this manufacturing process are high and the additional costs for this operation should be justified on a case-by-case basis. The advantages of isothermal forging are its low machining requirements, low scrap rate, part repeatability, and the final near clear shape, which encourages the use of small machines for forging due to the low heat loss. There are also disadvantages and these are; higher die material costs due to temperature and pressure, the need for uniform heating systems, protective atmosphere or vacuum to reduce oxidation of the die and material, and reduced productivity.
Material of forgings
Forgings can be made from a variety of materials. These include:
- Cast iron.
- Carbon steel.
- Alloy steel, such as stainless steel, nickel alloys and others.
- Copper and aluminium (metal forming).
- Brass (metal forming).
Other materials used for forgings include bronze, pure iron/steel castings, high-nickel content alloy steels and other specialty metals.
Standard for forgings
To facilitate the purchase of forgings, the ASTM International Committee on Forgings has developed a standard coding system that is used to identify forgings. This code is known as the forging grade designation system and it consists of a series of numbers, letters and symbols. For example, if you were looking for an A269 steel forging with a 1/16 inch thick flange face, you would need to know that this part has “FS” in its grade designation because it was produced using forging steel according to ASTM A269 standards.
If you’re having trouble locating a specific type of forging or want more information about how these parts are manufactured, contact your local custom fabricator today!
Dimensions of forgings
Dimensions are a necessary part of any forging, so you need to understand exactly what they mean and how you can use them. Dimensions are specified using a tolerance band or zone, which is a range within which the actual dimension can vary. The tolerance band will have an upper and lower limit (or two upper limits), and the size of this tolerance band depends on the material used for the part being forged. In some cases, there may be multiple dimensions that act together as part of a single specification—for example, if you have an outer diameter that comes with an inner diameter specification (ID/OD), then your overall dimensions will describe both values at once.
The most common unit used in specifications is inches (in), followed by millimeters (mm) and sometimes feet/yards (ft/yd).
Use of forgings
Forgings are used in a variety of industries, from automotive to aerospace to construction. Forgings are also utilized in medical, oil and gas, chemical, mining and power generation industries.
Inspection of forgings
- Precision: How precise are the forgings? Are there any deviations or inaccuracies in their form?
- Composition: How much of each material is in the forging, and how much of each material will be left after processing?
- Surface quality: Is there any surface damage to the forging that would affect its function, appearance, or durability?
- Surface roughness (Ra): What is its average Ra value, which measures how smooth or rough a surface is? The lower the number, the smoother it likely feels; however, this can vary depending on what kind of metal was used and what type of finish has been applied to it since then (if any). A higher value indicates rougher surfaces with more variation between them; for example rods made from different grades may have very high Ra values because they were machined differently yet still called “rod” afterward so long as they’re within industry standards for that particular type/grade.”
Packong of forgings
For forgings that are not too heavy, usually you can pack them in a box. Make sure the box is sturdy and strong enough to hold the weight of your product. Place foam sheets or other protective material between each piece of forging to ensure they don’t touch each other. If you are shipping a large number of pieces, consider using a crate instead of a single box for better protection during shipping.
For forgings that require extra reinforcement, consider using cartons or crates rather than just boxes because these will provide more structure when transporting them from place to place.
A pallet is another option for heavier items such as dies and molds; however, it may be difficult for some customers to load onto their trucks due to size constraints so keep this in mind when deciding how best to ship your product!
Delivery of forgings
The delivery of forgings is usually done by truck. The cost depends on the distance and size of the forgings. For example, if you order a 100-ton forging shipped from New York to California, it will be more expensive than if you ordered a 5-ton forging shipped from Boston to Chicago.
The delivery time depends on whether or not it’s necessary for us to make your part in advance and where we need to ship it from. We can generally have an item ready within 48 hours or less if necessary, but larger orders may take longer depending on our workload at that time.
We ship worldwide via ocean container (FCL) or air freight (LCL). If your order requires FCL shipping, we’ll provide information about who will handle customs clearance once your order arrives at its destination port in North America.
Where to buy forgings?
Asking the right questions will help you determine who is the right supplier for your company and what forging method can best meet your needs.
When you are considering forging suppliers, here are some questions to ask:
- What is the manufacturer’s experience?
- What capabilities does he/she have?
- Is his/her reputation good in the industry and with customers?
- Does he/she offer customer service that meets your needs?
- Is his/her financial stability concern for you?
- What technical support does he/she provide for your company’s operations and maintenance of forgings?
- Can the supplier deliver forging parts within your timeframe requirements and to specification requirements from the first shipment of material (if applicable)? This includes delivery of raw materials as well as finished forgings or steel castings or metal castings.
- What kind of quality control procedures does he use during production, such as heat treating or shot peening (if applicable)?
- How much will it cost if anything goes wrong with any part after delivery but before installation into an end product where it may be damaging to either property or persons.
Which forging process will create a part with the best mechanical properties?
You can use forgings to create many different types of parts. Depending on the strength requirements, material, and shape, the forging process use will vary.
Strength requirements determine whether a part should be made from mild steel or alloy steel. Alloy steels are stronger than mild steels but more expensive and harder to work with because they require special processing techniques. Forging is one such technique that can be used for both materials.
The size of the part will determine whether it should be cast or forged, as well as what shape it needs to have for casting or forging to be effective at creating a strong final product. In general, larger parts require casting because they’re too big for forging equipment (unless you have access to huge presses). Smaller parts are usually easier to forge than cast because they don’t need many intricate details that would make them too difficult for any equipment besides specialized tools like dies and hammers in order to achieve desired properties such as ductility (the ability of certain metals when the subject.
The forging process you select will depend on the type and size of the part you need to produce, according to the Metal Powder Industries Federation. The type of part you need to produce will determine the forging process you select, while its size will determine how much force is required during that process.
For example, a larger piece might require a huge amount of pressure for it to be shaped correctly. In this case, an open-face die forging could be more effective because it can apply more force than other types of dies. On the other hand, if your product doesn’t need very much shaping at all—like if all you want is a small screw with threads on both ends—then closed-face die forgings are probably better suited for your needs because they’re less likely to cause damage or deformations when applied with high amounts of pressure during their shaping processes.
What do I need to know about net shape forgings?
Net shape forgings are created by an upset forging process that changes a round billet into a square, hexagonal or rectangular shape. This can be done without machining if the part requires only one operation.
For example, if you have a part that needs to be made of alloy steel but has complex geometry and needs to withstand high temperatures, it’s best to use net shape forging. There are many applications for these forgings like gears, shafts, and other parts used in turbines and engines.
Net shape forgings, or net shape forgings, are created by an upset forging process that changes a round billet into a square, hexagonal or rectangular shape.
A typical example of this is the process used to create square steel bar stock for use in railroads and other transportation systems such as ships and aircraft.
Net shape forgings can be produced by several different forging processes. The most common include blanking, blooming, upsetting, and roll forming.
What do I need to know about closed die forgings?
Closed die forgings are made from a billet that is squeezed into a die. These forgings have more complex geometry than open die forgings, but they require close dimensional tolerances because they don’t have additional forging processes to help them achieve the required tolerance level.
These types of forgings are typically used to make complex shapes, such as piston rods and other engine components.
Closed die forging is a process that changes a round billet into a square, hexagonal or rectangular shape. The round billet is heated to the forging temperature (the metal’s transition point between solid and liquid), then placed in a closed die cavity on the press ram. As pressure is applied to the die, the metal flows out from its center into all corners of each corner angle of the shape. Once cooled, this shape becomes permanent as it cools into its new form without any distortion at all – even if it were made from thin material like metal sheet!
This ability allows for complicated geometries not possible with other methods; for example, an open-end wrench could be formed by cutting off one end of another wrench after forming had taken place because there was no distortion during cooling or machining steps necessitated by traditional machining methods like milling or turning.’
The quality produced by closed dies cannot be achieved by other manufacturing processes.
Closed die forgings have the best combination of strength, accuracy, and repeatability for complex geometries. They can produce very large parts, up to 30 feet in length. The cost is high, but more than offset by its superior quality versus other processes.
There are many considerations in choosing a manufacturer and forging method that fits your application needs:
- Closed die forgings are more expensive than open die forgings.
- Open die forgings are more expensive than net shape forgings.
- Net shape forgings are less expensive than stampings, but they aren’t as strong as closed die or open die forging methods.
Stampings cost less to produce than open or closed dies because you can use the same tooling for production runs of different sizes and shapes of parts, which is less costly than making a new set of tools for each part you want to be produced (like in an open-die process). They also require less finishing work since the material used for stamping doesn’t need any heavy forming steps like an extrusion does.