Forging Introduction:

What is forging:

Types of forging and their advantages and disadvantages:

    l Free forging

    l Die Forging

    l Hot forging

    l Warm forging

    l Cold forging

    l Special forging

    l Precision forging

    l Other forgings

Raw materials for forging:

Comparison between forgings and castings:

Forging application:

Production process of forgings:

Selection of forging factories:

1. What is Forging:

Forging is a metal part manufacturing process. Workers use forging machines, hammers, or other forging equipment to apply pressure to heated or unheated metal billets. Under the stress action, the billet will undergo plastic deformation and form a metal part with specific mechanical properties, shapes, and sizes. We also call this kind of metal parts forgings. We can optimize the element layout inside the ingredients through continuous forging so that the metal parts have better mechanical properties.

2. Types of Forging and Their Advantages and Disadvantages:

During the development of forging. Many forging technologies have grown, so there are many types of them. And there are many ways to classify them. For example, according to the different processing methods of billets, we can divide them into die forging and free forging; according to the heating temperature of billets, they can be divided into hot forging, warm forging, and cold forging; forging can even be based on the billets used for forging, forging Classify according to the mode of motion of the model.

The definition of each forging process will be introduced in detail below.


(1) Free Forging

We use a forging hammer to repeatedly beat the heated or unheated billet on the forging table. And the process of that beat the billet into a forging with the shape, size, and mechanical properties we need is free forging. It is very easy to understand because we can freely change the shape of the metal billet. The forging factory uses the upper and downer board of the press for free forging. The forging produced by the free forging method is called free forging.

Advantages and Disadvantages of Free Forging:

Advantages of Free Forging:

l Great forging flexibility, can produce small parts less than 100kg, and can also heavys as large as 300t or more;

l Forging tools are the most simple and easier to use;

l Only need smaller equipment to complete the production of forgings;

l Low precision requirements for equipment;

l The production cycle is short.

Disadvantages of Free Forging:

l Production efficiency is much lower than model forging;

l Forgings have simple shapes, low dimensional accuracy, and rough surfaces;

l Workers have high labor intensity and require a high technical level;

l It is High dependence on manual and difficult to achieve mechanization and automation.

(2) Die Forging

We cut the billet into a specific size and pretreat the billet (if necessary, we generally use electromagnetic induction heating equipment to heat the billet to a specified temperature and use the up and down tip irons to press the billet under the action of the forging press. The billet is forged into a specific shape before proceeding to the other process) and then the billet is put into the mold. Under the hydraulic press action, close the upper and lower dies, and the billet will be deformed in the forging die cavity under pressure action. After the die is opened, a forging with a specific shape, size, and mechanical properties is obtained. This forging process is die forging. We have compiled more information about die forging for you to understand it better. Some forging dies have flash grooves in addition to the forging chamber. This kind of die-forging process is called open-die forging; some forging dies have no flash grooves, and this kind of die-forging process is called Closed die forging. These two methods have their advantages and disadvantages. If you want to know about them, you can see the comparison between open-die forging and closed-die forging.

Advantages and Disadvantages of Die Forging:

Advantages of Die Forging:

l The production efficiency of die forging is high. During the forging process, metal parts can be formed in one shot in the die cavity.

l It can forge forgings with complex shapes, and can make the distribution of metal flow lines more reasonable, and improve the service life of parts;

l The size of the die forging is more accurate, the surface quality is better, and the machining allowance is smaller;

l Save metal materials and reduce cutting workload.

l Under the condition that the single batch of forgings' quantities is sufficient, the cost of parts can be reduced.

Disadvantages of Die Forging:

l The weight of die forgings is limited by the capacity of general die forging equipment, mostly below 7Kg;

l The manufacturing cycle of the forging die is long. And the cost is high;

l The investment cost of die-forging equipment is higher than that of free forging.


(3) Hot Forging

Sometimes we need to heat the billet above its recrystallization temperature before forging and then forging the billet to be forging we need. This forging process is hot forging. There is a new vocabulary here. If you don't understand it, you can check the content of recrystallization in Wikipedia.

There are two main ways to heat the billet during hot forging:

Flame heating:

Advantages: The fuel source is convenient, the furnace is simple to build, the heating cost is low, and the adaptability to the billet is wide.

Disadvantages: poor working conditions, slow heating speed, low efficiency, difficulty controlling heating quality, etc. This heating method is widely used in the heating of various billets.


Electric heating: There are several electric heating methods, such as induction-electric heating, contact electric heating, resistance furnace heating, and salt bath furnace heating.

The advantages are fast heating speed, less metal burning loss, unlimited heating temperature range, high thermal efficiency, low power consumption, low cost, simple equipment, and convenient operation.

Advantages and Disadvantages of Hot Forging:

Advantages of Hot Forging:

l The recrystallization process eliminates the strain-hardening effect as the metal deforms;

l Parts are more malleable, which makes them suitable for more industries;

l Forgings have a non-porous surface quality and can be polished and other surface treatments;

l Hot forging is more efficient when processing harder metals such as steel.

Disadvantages of Hot Forging:

l Hot forging requires a high-temperature operation. This will pose hidden dangers to personnel safety and material safety. Need More stringent operational management.

l The material is prone to oxidation at high temperatures, resulting in oxide skin that will lead to fouling on the forgings' surface and make poor smoothness and flatness.

l After the hot forging is completed, the forging material will shrink during the cooling process, affecting the dimensional accuracy of the forging.

l High-temperature operation requires higher equipment and maintenance costs.


(4) Warm Forging

Warm forging is a process in which we heat the billet to a temperature above room temperature and below the recrystallization temperature and then forge it to forgings that meet the requirements.

Advantages and Disadvantages of Warm Forging:

Advantages of Warm Forging:

l Compared with hot forging, warm forging can make forgings tighter tolerances.

l Compared with cold forging, the cost of dies is lower, and the requirements for forging machinery are also lower.

l Compared to cold forging. Reduced strain hardening and enhanced ductility.

l Forge some metal forgings that will have defects if produced by hot forging and cold forging.

Disadvantages of Warm Forging:

l Warm forging requires a high-temperature operation environment. This will pose hidden dangers to personnel safety and material safety. Need more stringent operation management.

l Need to control the billets' temperature in the warm forging process.


(5) Cold Forging

We call the forging process of the billet below the recovery temperature as cold forging.

Advantages and Disadvantages of Cold Forging:

Advantages of Cold Forging:

l Forgings are not easy to produce scale in the forging process, and the surface finish is better.

l Forgings will be more precise.

l Strain hardening occurs during processing, which increases forgings' strength and hardness.

l We can obtain the metal fiber flow direction of the forgings in a specific orientation.

l Compared with other manufacturing processes, it is more environmentally friendly;

l Forgings will be more consistent;

l Save more material.

Disadvantages of Cold Forging:

l The plasticity and toughness of forging materials are reduced, which may affect subsequent processing.

l The deformation force required is higher than hot forging.

l Residual stresses are generated inside the material.

l Metal grains can be deformed or broken.

l Directionality during processing may be detrimental to future product use.


(6) Special Forging

The special forging includes roll forging, cross wedge rolling, radial forging, liquid die forging, and other processes. These methods are more suitable for the production of parts with special shapes. Roll forging can be used as an effective preforming process to reduce the difficulty of the subsequent forming; cross wedge rolling can produce steel balls, transmission shafts, and other parts; radial forging can produce large forgings, such as barrels and stepped shafts.


(7) Precision Forging

Some forging processes can directly forge forgings that can be used without finishing or with a small amount of processing. We call this forging process precision forging. Precision forging is a kind of advanced metal manufacturing technology widely used and has irreplaceable advantages. If you want to know more about it, you can read Precision Forging.

(8) Others Forging

There are many classification methods of forging, so there are many names. For example, we can divide forging into pendulum forging, pendulum swivel forging, roll forging, cross wedge rolling, ring rolling, and cross rolling according to the different movement modes of the forging die.

(9) About the Types of Forging

In addition to simple forgings, more complex forgings may require many forging processes, such as roll forging and cross-rolling, which can be used as a pre-processing process for thin and long materials. Free forging can be used to perform the billet before die forging. So A forging part may need many types of forging processes. If you have a metal part that needs to be produced, it is recommended that a professional forging service provider develop a complete production solution for you.


3. Raw Materials for Forging:

We can use forging can manufacture metal parts for most raw materials. For example, metal parts made of carbon steel and alloy steel of various components, aluminum, magnesium, copper, titanium alloy, iron-based superalloys, nickel-based superalloys, and deformed alloys of cobalt-based superalloys.

There are many kinds of metalworking processes. To determine whether the product is suitable for the forging process and which forging process to use needs to be comprehensively judged according to the size, size, complexity, mechanical properties, and other requirements of the product. If you have drawings, you can contact a professional metal manufacturer. A responsible metal processing service provider will help you formulate a complete production solution.

The Original Form Types of Raw Materials and Selection

The forging factory will choose the suitable original form from the bar, ingot, powder, and liquid according to the size of the forging. We generally use round or square bars as billets when forging small and medium-sized forgings because the bar has uniform grain structure and good mechanical properties, the right shape and size, good surface quality, and is convenient for mass production. As long as the forging plant reasonably controls the heating temperature and deformation conditions, it can forge forgings with excellent performance without large forging deformation.


Forging factories only use ingots when making large forges. The ingot-type billets have cast structure, larger columnar crystals, and porosity centers. If only a low plastic deformation can not better break the columnar crystals into tiny grains and compact the porosity structure. The production of large forgings requires higher plastic deformation, which can solve the above problem. Forgings can obtain excellent metal structure and mechanical properties.


We generally use powder billets when forging small forgings, such as gears that require higher precision and better mechanical properties. Because the powder billet can be made into forgings with better mechanical properties and more precise through closed-die forging under heating, which can reduce finishing. However, the price of powder billets is much higher than that of general billets.


For those complex thin-walled parts that are difficult to form by die forging, it is necessary to use liquid billets to complete the forging. The specific method is to apply static pressure to the liquid billet poured in the die cavity so that it flows, solidifies, crystallizes, plastically deforms, and forms under pressure. Liquid metal die-forging is a forming method between die casting and die forging.


Note: The ratio of the cross-sectional area of the metal before deformation to the cross-sectional area after deformation is called the forging ratio. Correct selection of forging ratio, reasonable heating temperature and holding time, initial forging temperature and final forging temperature, and reasonable deformation amount and deformation speed has a great relationship with improving product quality and reducing costs.

4. Compere with Forgings and Castings

The comparison between castings and forgings can be carried out from 7 aspects. You can read comparing castings and forgings from 7 angles to know more about it.


Forgings and castings are commonly used in metalworking processes and are widely used. They have their advantages and disadvantages, and it is necessary to choose whether to use forging or casting to complete the processing according to the various performance requirements of the metal parts. If you don't know which process your products need to use, don't worry. You can send product samples or drawings to HULK Metal. As a metal manufacturer, we will help you choose a more suitable process and formulate a complete production solution. Fulfill your order faster.

5. Application of Forgings:

Forgings have properties that metal parts produced by other processes do not have and have an irreplaceable position in life. Of course, different industries have different requirements for forgings, so we need to choose a more suitable forging process to complete the order. This will not only improve the production efficiency of the order but also reduce the cost of the order.

The core application industries for these large forgings are listed below. In life, we can see many small forgings. For example, many screws are manufactured by machining after cold forging.

1. Aerospace.

2. Power equipment: diesel engine, engine.

3. Shipping industry

4. Military Industry

5. Mining machinery

6. Power industry

7. Petrochemical industry


6. Production Process of Forgings:

As mentioned above, a forging production often requires more than one type of process. If the forging factory is professional enough, they will be able to formulate a complete production solution according to the drawings and production requirements provided by you. This solution generally includes the production cycle of the forging, the packaging method and material of the order, the shipping method and delivery cycle, and the price of the order.


1. Drawing design;

After we know the purpose of the forging, we need to make drawings according to its shape. There will be various requirements for the forging on the drawing, such as the size and material. Drawings will facilitate the technical team to better measure the size of forgings and calculate the order price, as well as subsequent mold making and billeting.


2. Design the Production Process of Forgings According to the Drawings;

After the drawing design is completed, we will generate a 3D structure according to the drawing and combine various forging processes according to the complexity of the forging to complete the production of the order faster. In addition to the forging process, CNC machining may also be used to treat the forging surface or adjust the shape of the forging.


3. Quality Control;

Quality control is integrated into the entire production process of forgings. A professional and advanced forging factory will have a quality control center that will strictly test the indicators of raw materials, semi-finished products, and finished products.


4. Raw Material Procurement and Testing;

The forge will be responsible for the procurement and quality inspection of raw materials. Quality control from materials can avoid the re-production of semi-finished products or finished products that fail to meet production requirements due to unqualified raw materials during the order production process, shortening the production cycle.


5. Cutting;

Cut raw materials to specific sizes. There are many cutting methods, such as laser cutting and sawing. Use which cutting methods depends on the production process and the factory‘s production capacity.


6. Pretreatment;

According to the production process of forgings, trim and heat the billets.


7. Preforming;

In general. Before the forging process, pre-perform the heated billet by free forging, roll forging, and other forging processes. The preformed billet can be better filled into the cavity. This process reduces the generation of defective products.


8. Forming;

Put the preformed billets in the mold and close the mold by using forging equipment. And then, open the molds and can get forgings with or without flash according to the characteristics of the mold.


9. Finishing the Forgings;

We need cut and polished forgings with flashes to remove flashes after the forgings are cooled; forgings without flash only need simple surface treatment or none at all. According to the requirements, the forgings need to pass CNC machining, and the finishing of the forgings is completed by turning, milling, grinding, drilling, and other processes, and then carrying out the surface treatment to obtain the final product.


10. Packaging and Storage;

After the finished product is produced, it is packaged according to the requirements. The packaged goods will be placed in the warehouse, waiting for delivery.


11. Delivery;

There are many delivery methods, such as FOB, CFR, etc., and most companies support all delivery methods. An experienced forging company will have a freight team to provide freight consulting services.


12. After Sales.

A responsible forging company will provide comprehensive after-sales service to guarantee product quality. HULK Metal will provide a return, replenishment, and exchange services for each customer and actively communicate with each customer to negotiate a perfect solution.


Because different forgings have different production processes, we can only talk about the production process of forgings in general. If you want to know the forging processes, you can choose to click the link to learn more:

Die Forging Process:

Free Forging Process:

Warm Forging Process:

Cold Forging Process:

Hot Forging Process:

Roll Forging Process:

7. Selection of Forging Factory

To choose a suitable forging factory, you first need to comprehensively compare the quotations given to you by multiple forging factories and choose the one with excellent serviceability and production capacity as the main cooperative factory under the premise that the price difference is not many and the other as an alternative Or place orders to multiple companies at the same time in proportion to improve the ability to resist risks. The service capability and production capacity of the forging company are mainly reflected in the following 6 points:


1. The technical team can quickly work out a production solution with a more suitable price, a shorter production cycle, and a more suitable delivery time based on the drawings or samples you provide.

2. The factory can strictly implement the ISO9001 quality management system and has at least 20 forging machine tools and testing equipment, which can complete the production of molds and samples faster and send them to you for testing after you pay the advance payment.

3. The production team has rich experience and can complete your order faster.

4. Have a professional quality inspection team to control the overall quality of the order.

5. Can provide more professional freight consulting services, optimize freight routes, reduce freight costs, and provide other freight-related services.

6. With after-sales service, when there are quality problems with the product, we can put forward a better solution centered on you.


HULK Metal has been engaged in metal forging services since the second half of the 20th century. We have a complete service system. If you have any needs, you can contact us at any time.


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