Pipe joint forgings

Cold forging is a general term for plastic processing such as cold die forging, cold extrusion, and cold heading. It is the forming process of the material below the recrystallization temperature, and the forging is carried out below the recovery temperature. In production, forging without heating the blank is called cold forging.

Most of the cold forging materials are aluminum and some alloys, copper and some alloys, low carbon steel, medium carbon steel, and low alloy structural steel with low deformation resistance and good plasticity at room temperature. Cold forgings have good surface quality and high dimensional accuracy, which can replace some cutting processes. Cold forging can strengthen the metal and increase the strength of the part.

Introduction of cold forging process

Locomotive forgings

Cold precision forging is a (near) net shape forming process. The parts formed by this method have high strength and precision and good surface quality. At present, the total amount of cold forgings used in an ordinary car abroad is 40~45kg, of which the total amount of toothed parts is more than 10kg. The single-piece weight of cold forged gears can reach more than 1kg, and the tooth shape accuracy can reach 7 grades.

Continuous process innovation has promoted the development of cold extrusion technology. Since the 1980s, domestic and foreign precision forging experts have begun to apply the split forging theory to the cold forging of spur and helical gears. The main principle of shunt forging is to establish a shunt cavity or shunt channel of material in the forming part of the blank or die.

During the forging process, while the material fills the cavity, part of the material flows to the shunt cavity or shunt channel. The application of shunt forging technology enables the less and no cutting processing of higher precision gears to quickly reach an industrial scale. For extruded parts with a length-diameter ratio of 5, such as piston pins, cold extrusion can be achieved at one time by axial shunt by using a wide range of axial residual blocks, and the stability of the punch is very good; for flat spur gears Forming, the use of radial residual blocks can also achieve cold extrusion forming of products.

Locking frame forgings

Blocked forging is to extrude metal in one or two directions through one or two punches in a closed die at one time to obtain near-net shape precision forgings without flash. If some car precision parts such as planetary and half shaft gears, star sleeves, cross bearings, etc. are processed by cutting, not only the material utilization rate is very low (less than 40% on average), but also it takes a lot of man-hours and the production cost is extremely high. These net shape forgings are produced in foreign countries using occlusion forging technology, which saves most of the cutting process and greatly reduces the cost.

Advantages and disadvantages of cold forging

Limit wear plate

Cold forging process is a precision plastic forming technology, which has unparalleled advantages of cutting, such as good mechanical properties, high productivity and high material utilization rate of products, especially suitable for mass production, and can be used as a manufacturing method for final products. , It has a wide range of applications in industries such as transportation, aerospace and machine tool industries.

Material requirements are high; not suitable for small amounts of processing; mold requirements are high.

The above is a detailed introduction to the cold forging process. The forming accuracy of cold forging technology is higher than that of warm forging and hot forging, and it has its unique advantages in the field of precision forming. The application of the cold forging process improves the bore finish, dimensional accuracy and surface strength, prolongs the life of the barrel, and improves the shooting accuracy of the gun accordingly, and it is easy to process the tapered barrel and reduce the quality.

Pipe joint forgings

Free forging is a processing method that uses impact force or pressure to deform the metal freely in all directions between the upper and lower anvil surfaces, and obtains the required shape and size and certain mechanical properties without any restriction, which is referred to as free forging. The tools and equipment used in free forging are simple, versatile and low in cost. Compared with casting blanks, free forging eliminates shrinkage holes, shrinkage porosity, pores and other defects, so that the blanks have higher mechanical properties. Forgings are simple in shape and flexible in operation. Therefore, it has special significance in the manufacture of heavy machinery and important parts.

Basic process of free forging

The basic processes of free forging include upsetting, drawing, punching, bending, torsion, offset, cutting and forging.


A forging process that reduces the height of the blank and increases the cross-sectional area. The upsetting process is mainly used for forging gear blanks and round cake forgings. The upsetting process can effectively improve the blank structure and reduce the anisotropy of mechanical properties. Repeated upsetting and drawing can improve the morphology and distribution of carbides in high-alloy tool steels.

Agricultural machinery bearing sleeve

Upsetting mainly has the following three forms:

1. Complete upsetting. Complete upsetting is to place the blank vertically on the anvil surface, and under the hammering of the upper anvil, the blank will be plastically deformed with a height reduction and an increase in the cross-sectional area.

2, the end upsetting. After the billet is heated, one end is placed in a drain or mold to limit the plastic deformation of this part, and then the other end of the billet is hammered to make it upsetting. The upsetting method of the leaking disc is mostly used for small batch production; the method of upsetting the tire mold is mostly used for mass production. Under the condition of single-piece production, the part that needs upsetting can be heated locally, or after all heating, the part that does not need upsetting can be chilled in water, and then upsetting is performed.

3. Upsetting in the middle. This method is used for forging forgings with large middle section and small sections at both ends. For example, gear blanks with bosses on both sides are forged by this method. Before the upsetting of the billet, both ends of the billet should be thinned first, and then the billet should be upright in the middle of the two leakage pans for hammering to make the middle part of the billet upsetting. In order to prevent the billet from bending during upsetting, the ratio of the billet height h to the diameter d h/d ≤ 2.5.

Pull out

Elongation, also known as elongation, is a forging process that reduces the cross-sectional area of ​​the billet and increases its length. Drawing length is often used for forging rods and shaft parts. There are two main methods of pulling out:

1. Pull out on the flat anvil.

2. Pull out on the mandrel. During forging, the mandrel is first inserted into the punched billet, and then drawn as a solid billet. When drawing long, it is generally not drawn at one time. First, the blank is drawn into a hexagonal shape, and after forging to the required length, the chamfer is rounded and the mandrel is taken out. In order to facilitate the removal of the mandrel, the working part of the mandrel should have a slope of about 1:100. This drawing method can increase the length of the hollow blank, reduce the wall thickness, and keep the inner diameter unchanged. It is often used for forging long hollow forgings such as sleeves.

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There are two main methods of punching:

1. Double-sided punching method. When the punch is punched to the depth of 2/3 to 3/4 on the blank, take out the punch, turn the blank, and then use the punch to align the position from the reverse side to punch out the hole.

2. Single-sided punching method. For blanks with small thickness, single-sided punching method can be used. When punching, the blank is placed on the backing ring, the big end of a slightly tapered punch is aligned with the punching position, and the blank is hammered into the blank until the hole penetrates.


The forging process in which a certain tool and die bends the blank into a specified shape is called bending.

There are two commonly used bending methods:

1. Forging hammer compression bending method. One end of the blank is pressed by the upper and lower anvils, and the other end is struck with a sledgehammer or pulled by a crane to bend it into shape.

2. Die bending method. Bending in the pad die can obtain small forgings with more accurate shape and size.
Cutting refers to the forging process in which the blank is divided into several parts or partially cut, or a part is cut from the outside of the blank, or a part is cut from the inside.



Torsion is a forging process that rotates one part of wool by an angle about its axis relative to another. This process is mostly used for forging multi-turn crankshafts and correcting some forgings. When the torsion angle of the small billet is not large, the hammering method can be used.


Staggering refers to the forging process in which one part of the blank is staggered parallel to another part by a distance, but the axis is still kept parallel. It is often used for forging crankshaft parts. When staggered, the blank is first cut locally, and then impact force or pressure of equal size, opposite method and perpendicular to the axis is applied on both sides of the incision, so that the blank can be offset.


Forging is a forging process in which the billet is heated to a high temperature in a furnace, and then struck with a hammer to combine the two in a solid state. Forging methods include lap joint, butt joint, snap joint and so on. The strength of the seam after forging can reach 70% to 80% of the strength of the connected material.

The above is all about the basic process of free forging. I hope it can be helpful to everyone. If you have any questions during the operation, you can contact us at any time.


Free forging is what we call free forging, which is completed by gradual local deformation of the blank on the flat anvil or between the tools. Because the tool is in contact with the blank part, the stagnant grid work is much smaller than the die forging bar for the production of forgings of the same size, so free forging is suitable for forging large forgings. Of course, free forging also has certain advantages and disadvantages in the forging process. Yes, let’s find out together!

Agricultural machinery lifting arm

The advantages of free forging :

(1) Free forging can improve the structure and properties of metal. The quality and mechanical properties of metal free forgings are higher than those of castings, and their strength is 50% -70% higher than that of castings, so they can withstand large impact loads. Forgings can reduce the weight of the parts themselves on the premise of ensuring the design strength of the parts, which is of great significance to aerospace and transportation.

(2) Free forging can save raw materials. Parts with shapes closer to the part can be produced using the free forging method.

(3) Free forging is suitable for single-piece small batch production, and the variety is more flexible.

(4) Since there is no lateral flow in the straight shaft or curved shaft parts and annular parts, the streamline distribution is generally more reasonable than that of die forgings. It is especially suitable for straight or curved shafts, discs or rings with simple shape, small cross-section change and gentle main axis.

(5) Some special quality torsion requirements can be met by the free forging process, such as reverse upsetting can improve the quality of raw materials.

Other agricultural machinery forgings

The disadvantages of  free forging:

(1) Compared with die forging, the material utilization rate of free forgings is low, and the machining area is larger. The clarity and straightness of the flow pattern and the degree of agreement along the outer contour of the forging are worse than those of die forgings. During the machining process, Metal streamlines are easily cut.

(2) Compared with die forgings, the mechanical properties of aluminum alloy free forgings are relatively low.

(3) The forging production method has lower production efficiency than other pressure processing methods, and the degree of mechanization and automation needs to be improved.

(4) The degree of forging deformation is not uniform enough. The uniformity of the shape and size of the same batch of forgings is worse than that of die forgings. Due to the comparison of fire, complex forgings are only heated and do not participate in deformation in some parts. Therefore, it may be It leads to the appearance of inhomogeneous structure or low magnification coarse grains.

(5) Compared with die forging, the quality of free forgings is more affected by the forging process and the level of forging operations.

The above is all about the advantages and disadvantages of free forging. In fact, there are various forging processes, which should be selected according to the actual forging needs. Different processes have different advantages and disadvantages, and must be understood in advance.

Agricultural machinery lifting arm

The die forging process has high production efficiency, low labor intensity, accurate dimensions, small machining allowance, and can forge forgings with complex shapes; it is suitable for mass production. However, the cost of the die is high, and special die forging equipment is required, which is not suitable for single-piece or small batch production. Therefore, the quality of die forgings is also more concerned by users. Correctly understand the main factors affecting the quality of die forgings. very important meaning.

The main factors affecting the quality of die forgings

Other agricultural machinery forgings

1. Defects in raw materials

For example, there are residual shrinkage holes, bubbles, porosity, inclusions, etc. in the ingot or steel, which may cause the forging to crack. Forging cracks caused by metallurgical reasons are often accompanied by a large number of oxides, sulfides, silicates and other inclusions. The raw materials of high carbon and high alloy steel are prone to serious segregation of second phases such as carbides. If they are not crushed and evenly distributed during forging, the mechanical properties of the forgings will be reduced, and the forgings may be cracked or evenly distributed during heat treatment. distortion. If there are scratches, scars, folds and cracks on the surface of the raw material, it will bring defects to the forgings. Therefore, raw materials must be inspected in die forging production.

2. Heating specification

When forging large die forgings and alloy steel die forgings, if the heating speed is too fast, the temperature difference between the inner and outer layers will be large, and the central part will be cracked due to temperature stress and structural stress.
When the heating temperature is too high and the holding time is too long to cause slight overheating, a lustrous, crystalline, and intergranular fracture will be produced. Coarse grains that are slightly overheated can be corrected by annealing or normalizing, followed by recrystallization. In severe overheating, fractures or stone fractures will occur. The characteristics of the fracture are fish-scale bright spots and transgranular fracture; the reason for the fracture is that the coarse austenite grains form an intragranular texture with extremely high stability. Texture characteristics are preserved.

Harvester pusher

The stone-like fracture has obvious coarse crystals, the surface has no metallic luster, the color is gray, and the intergranular fracture is caused. Saturated coarse austenite precipitates, surrounding austenite grains to form brittle crystal shells. Severely overheated forging billets have extremely poor mechanical properties. The naphthalene-shaped fracture can be normalized at high temperature to eliminate the intragranular texture, while the stone-shaped fracture is difficult to be corrected by heat treatment.
The forging heating temperature is low, and when the heat is not penetrated, cracks with transgranular propagation may occur, and the tail ends are sharp. When there is no subsequent heating process, there is no oxidation and decarburization on the surface of the cracks.
For alloy structural steel, if the final forging temperature is too high, the austenite will continue to grow after final forging, even exceeding the original grain size. Coarse-grained fractures can be seen in fracture inspection, and Widmanderin microstructure appears in high magnification observation. If the final forging temperature is too low, the steel is in the dual-phase region, the inclusions are distributed along the main deformation direction of the blank, and the ferrite precipitated from the austenite preferentially adheres to the surface of the inclusions to form a banded structure. Widmanderin and banded structures reduce the mechanical properties of forgings, especially the impact toughness. In order to refine the grains, improve the structure, and improve the mechanical properties, the steel with such a structure must be completely annealed to recrystallize it.

3. Die forging process

Different forms of die forging are used, such as open die forging, closed die forging, extrusion, upsetting, high-speed die forging, rolling, etc. The essence is to apply different forms to the blank through corresponding die forging equipment and dies. The thermal and mechanical conditions make it produce different physical fields and evolution processes of tissue properties. For the same forging, whether the selection of the deformation method is reasonable or optimal, the quality of the die forgings is very different. The wrong selection may make the forming process impossible, and the unreasonable selection will make the forming difficult and prone to many quality problems.

Cam forging

The die forging process parameters such as deformation temperature, deformation speed and degree of deformation are obviously directly related to the quality of die forgings. For example, for ingots or some materials, it is necessary to compact the structure and refine the grains through deformation. If the forging deformation is small, the expected effect cannot be obtained; some non-ferrous metals, especially high-strength aluminum alloys, magnesium alloys, etc. , requires a small deformation speed and an appropriate degree of deformation, and is suitable for forming on a press, which helps to avoid cracks.

The quality of die forgings is also related to forging design and forging die design. The selection of machining allowance and forging tolerance should be based on reality. If the specification is too small, it is easy to cause waste after machining due to surface defects and dimensional errors. Whether the design of the structure and the flash structure is appropriate will affect the flow and filling quality of the metal; if the setting of the lock is ignored, the size of the forging will be out of tolerance due to the misalignment of the upper and lower dies. In addition, the installation and tightening, preheating, cooling and moistening of the forging die should comply with the specifications, and the violations should be checked at any time and corrected in time.

The above is all about the factors affecting the quality of die forgings. Every link in the production of die forging will have a non-negligible impact on the quality of the forgings. Strictly follow the relevant quality inspection and control in the production process to ensure the quality of the die forgings.

Forging equipment

In forging processing, forging equipment is mainly used for metal forming and metal separation, so it can also be called metal forming machine tool. The forming principle of forging equipment is to exert pressure on the metal, and the large impact force is the main feature of this type of equipment. Therefore, in order to ensure the normal operation of the equipment and the personal safety of operators, various safety protection devices will be installed on the equipment.

There are many types of forging equipment, which can be divided into forming equipment and auxiliary equipment. The forming equipment includes forging hammers, mechanical presses, hydraulic presses, screw presses, and flat forging machines. machine etc. In the current processing industry, hammer forging equipment, hot die forging press, screw press, flat forging machine, hydraulic press, etc. are commonly used forging equipment in forging workshops.

Forging equipment–forging hammer

Among the forging equipment, the most widely used equipment is the non-forging hammer. When the forging hammer is working, after the high-speed movement generates kinetic energy through the falling of the heavy hammer or the processing external force, the processed blank is forged to plastically deform the product. The forging hammer has the characteristics of simple structure, flexible work, wide application and easy maintenance, and can be used for free forging and die forging.

Forging equipment

Forging Equipment–Hot Forging Press

Hot die forging press is a very commonly used high-precision forging equipment in modern forging production. It can be used to produce large quantities of die forging and finishing forgings of ferrous and non-ferrous metals. The forgings produced by this processing method have higher precision and can be It uses raw materials to a greater extent, has a high degree of automation, and is easy to operate, which greatly improves the production efficiency of products. It is widely used in automobiles, ships, aviation, mining machinery, petroleum machinery, hardware tools and other manufacturing industries.

Forging equipment–screw press

Screw presses, according to their processing methods, can be divided into two types, one is a device that generates static pressure by applying torque to the bolt, and the other is a device that generates pressure through the rotation of the flywheel device on the bolt, and the metal blank is once forming equipment.
The screw press is mainly used for the processing of various high, medium and low-grade refractory materials. Forging, casting and forging.

Forging Equipment–Flat Forging Machine

Horizontal forging machine is a flat forging machine. It can be used to produce die forgings. This equipment adopts the method of local upsetting, which can realize the work of punching, bending, flanging, trimming and cutting. Flat forging machines have high productivity and can be used for mass production. Widely used in automobile, tractor, bearing and aviation industries.

Forging equipment–hydraulic press

Hydraulic presses, as the name suggests, are equipment for processing metal, plastic, rubber, wood, powder and other blanks through hydrostatic pressure. The hydraulic press used for forging is generally a hydraulic press with a high tonnage.

The hydraulic press is suitable for various processes such as bending, forming and flanging of central load parts. When used with a punching buffer device, it can also perform punching and blanking processing. The use of hydraulic presses in ships, pressure vessels, chemical industries and other industries will be more many.

The above content mainly introduces the commonly used forging equipment in the processing industry. If you need other forging related knowledge such as forging category, forging process, forging characteristics, etc., you are welcome to call the 24-hour consultation hotline, the company’s official website: www.gold-emperor. com.

Hose connector

Forging is the use of forging pressure on metal blank products by forging machines to plastically deform the processed forgings to achieve specific mechanical properties, shapes and sizes. This is an important metal plastic processing method adopted by many forging manufacturers. Many people know about forging, but they don’t know much about the forging process. Today, GOLD EMPEROR FORGING, a forging manufacturer, will share with you some common forging processes.

Classification according to forging temperature:

First of all, the forging process can be classified according to the forging temperature, commonly used are hot forging, warm forging and cold forging.

Classification according to forming principle:

Secondly, we can also divide the forging process into free forging, die forging, ring rolling and special forging according to the forming principle of forgings.

forging process

1. Free forging of forging process

Using simple universal tools, or directly applying external force to the blank between the upper and lower anvils of the forging equipment, the blank is deformed, and the processing method of the forging to obtain the required geometric shape and internal quality is free forging. Forgings produced by the free forging method can be called free forgings. Free forging is mostly used to produce small batches of forgings. We can use forging equipment such as forging hammers and hydraulic presses to form and process the blanks to obtain qualified forgings. The basic processes of free forging include upsetting, drawing, punching, cutting, bending, torsion, offset and forging. Free forging is all hot forging.

2. Die forging of forging process.

Die forging can be divided into open die forging and closed die forging. After the metal blank is compressed and deformed in a forging die cavity with a certain shape, the required forgings can be obtained. Die forging is mostly used to produce important light and large-scale parts.

Die forging can be divided into hot forging, warm forging and cold forging. In the future, warm forging and cold forging will use more die forging processes, which are more difficult to forge than other forging methods, and can better reflect the forging technology level of forging manufacturers.

According to forging materials, die forging can also be divided into ferrous metal die forging using ferrous metals such as carbon steel, non-ferrous metal die forging using non-ferrous metals such as copper and aluminum, and powder product forming with powder metallurgy materials.

forging process

3. Rolling ring of forging process.

Ring rolling refers to the method of forging and processing ring parts of different diameters using special equipment such as ring rolling machines. This method can be used to produce wheel-shaped parts such as automobile hubs and train wheels.

4. Special forging of forging process.

Special forging mainly refers to forging methods such as roll forging, cross wedge rolling, radial forging, liquid die forging, etc. These methods can be used to produce forgings with special shapes.
For example, roll forging can be used as an effective preforming process to greatly reduce the subsequent forming pressure; cross wedge rolling can produce parts such as steel balls and drive shafts; radial forging can produce large forgings such as barrels and stepped shafts.

The above is the introduction of common forging processes organized by the forging manufacturer–GOLD EMPEROR FORGING. I hope it can help you! We are a forging supplier from China, specializing in the forging of auto parts, construction machinery parts, mining equipment parts, electromechanical forgings and other products, providing a full range of forging services for customers who need to use various forgings.

Harvester pusher

In forging production, in addition to ensuring the required shape and size of the forging, it must also meet the performance requirements put forward during the use of the parts, which mainly include: strength index, plastic index, impact toughness, fatigue strength, fracture initial and Stress corrosion resistance, etc. For parts working at high temperature, there are also high temperature instantaneous tensile properties, durable properties, anti-deformation properties and thermal fatigue properties.

Influence of Forging on Metal Microstructure and Properties

The raw materials for forging are ingots, rolled products, extruded products and forging billets. Rolled material, extruded material and forging billet are semi-finished products formed by rolling, extruding and forging of ingots respectively. In forging production, using reasonable process and process parameters, the structure and properties of raw materials can be improved through the following aspects:

1. Break the columnar crystals, improve the macrosegregation, change the as-cast structure to the forged structure, and weld the internal pores under suitable temperature and stress conditions to improve the density of the material;

2. The ingot is forged to form a fibrous structure, and further through rolling, extrusion and die forging, the forgings can obtain a reasonable distribution of fiber directions;

3. Control the size and uniformity of grains;

4. Improve the distribution of the second phase (for example: alloy carbides in ledeburite steel);

5. To make the organization get deformation strengthening or deformation strengthening, etc.

Due to the improvement of the above structure, the plasticity, impact toughness, fatigue strength and durability of the forgings are also improved, and then the required hardness, strength and plasticity of the parts can be obtained through the final heat treatment of the parts. performance.

However, if the quality of the raw materials is poor or the forging process used is unreasonable, forging defects may occur, including surface defects, internal defects or unqualified performance.

Other agricultural machinery forgings

Influence of raw materials on the quality of forgings

The good quality of raw materials is a prerequisite to ensure the quality of forgings. If the raw materials are defective, it will affect the forming process of the forgings and the final quality of the forgings.

If the chemical elements of the raw materials exceed the specified range or the content of impurity elements is too high, it will have a greater impact on the forming and quality of the forgings. Appears hot and crisp. In order to obtain intrinsically fine-grained steel, the residual aluminum content in the steel needs to be controlled within a certain range, such as 0.02% to 0.04% (mass fraction) of A1 acid. If the content is too small, it will not be able to control the grain size, and it is easy to make the essential grain size of the forgings unqualified; if the aluminum content is too much, it is easy to form wood grain fractures under the condition of forming fibrous structure during pressure processing. Tear-shaped fractures, etc. For another example, in austenitic stainless steel, the more n, Si, Al, and Mo are contained, the more anionite phase, the easier it is to form band cracks during forging, and make the parts magnetic.

For example, there are defects such as shrinkage tube residue, subcutaneous foaming, severe carbide segregation, and coarse non-metallic inclusions (slag inclusions) in the raw materials, which are easy to cause cracks in the forgings during forging. Defects such as dendrites, severe porosity, non-metallic inclusions, white spots, oxide films, segregation bands and mixed metals in the raw materials can easily cause the performance of forgings to decline. Surface cracks, folds, scars, and coarse-grained rings of raw materials are likely to cause surface cracks in forgings.

Influence of forging process on the quality of forgings

The forging process generally consists of the following steps, namely blanking, heating, forming, cooling after forging, pickling and heat treatment after forging. If the forging process is improper, a series of forging defects may occur.

The heating process includes furnace loading temperature, heating temperature, heating speed, holding time, furnace gas composition, etc. Improper heating, such as too high heating temperature and too long heating time, will cause defects such as decarburization, overheating, and overburning.

For the bad material with large cross section, poor thermal conductivity and low plasticity, if the heating speed is too fast and the holding time is too short, the temperature distribution will be uneven, thermal stress will be caused, and the forging blank will be cracked.

The forging forming process includes deformation method, deformation degree, deformation temperature, deformation speed, stress state, tool and die condition and lubrication conditions. Overlap, flow through, eddy current, as-cast structure residue, etc.

During the cooling process after forging, if the process is improper, it may cause cooling cracks, white spots, network carbides, etc.

Other agricultural machinery forgings

Influence of Forging Microstructure on Microstructure and Properties after Final Heat Treatment

Austenitic and ferritic heat-resistant stainless steels, superalloys, aluminum alloys, magnesium alloys, etc. have no allotropic transformation during the heating and cooling process, as well as some copper alloys and titanium alloys, which are produced during the forging process. The structural defects cannot be improved by heat treatment.

Materials with allotropic transformation during heating and cooling, such as structural steel and martensitic stainless steel, etc., due to some structural defects caused by improper forging process or some defects left over from the original material, the forgings after heat treatment Quality has a big impact. An example is as follows:

1. The microstructure defects of some forgings can be improved during post-forging heat treatment, and satisfactory microstructure and properties can still be obtained after final heat treatment of forgings. For example, coarse grains and Widmandering structures in generally overheated structural steel forgings, hypereutectoid steels and bearing steels with slight network carbides caused by improper cooling, etc.

2. The structural defects of some forgings are difficult to eliminate with normal heat treatment, and can be improved by measures such as high-temperature normalizing, repeated normalizing, low-temperature decomposition, and high-temperature diffusion annealing.

Master axis

3. The structural defects of some forgings cannot be eliminated by the general heat treatment process, resulting in the performance of the forgings after the final heat treatment being reduced or even unqualified. For example, severe stone fractures and facet fractures, overburning, ferrite strips in stainless steel, carbide meshes and strips in ledeburite high alloy tool steels, etc.

4. The structural defects of some forgings will further develop and even cause cracking during the final heat treatment. For example, if the coarse grain structure in alloy structural steel forgings is not improved during heat treatment after forging, it will often cause coarse martensite and unqualified properties after carbon, nitriding and quenching; material, quenching often causes cracking.

Different forming methods have different stress and strain characteristics due to different stress conditions, so the main defects that may occur are also different. For example, the main defect when the billet is upsetting is the cracks in the longitudinal or 45° direction on the side surface, and the as-cast structure is often left on the upper and lower ends of the upsetting ingot; the main defect when the rectangular section billet is elongated is the transverse crack on the surface and corner cracks, internal diagonal cracks and transverse cracks; the main defects in open die forging are filling, folding and misalignment.

Different types of materials, due to their different compositions and structures, have different microstructure changes and mechanical behaviors during heating, forging and cooling processes. Therefore, when the forging process is not appropriate, the defects that may occur also have their particularities. For example, the defects of ledeburite high alloy tool steel forgings are mainly coarse carbide particles, uneven distribution and cracks, the defects of superalloy forgings are mainly coarse grains and cracks; the defects of austenitic stainless steel forgings are intergranular chromium depletion, The resistance to intergranular corrosion is reduced, ferrite band structure and cracks, etc.; the defects of aluminum alloy forgings are mainly coarse grains, folding, eddy currents, and flow through.


Gear forgings, as the name suggests, are a kind of gear produced by forging technology. The performance of gear forgings will be more stable, and the damage rate will be reduced a lot during operation, so the demand for gear forgings is very large.

Gear forgings are also a kind of forging products. When forging, it needs to be carried out according to the rules. At the same time, some hard technical requirements need to be met. Now forging manufacturers will introduce the technical requirements of gear forgings.


1. The allowance size of gear forgings should conform to national standards.

2. Gear forgings should ensure a suitable forging ratio during forging, and should not be forged with round steel of similar size.

3. Do not use billet forging.

4. The material of gear forgings should be consistent with the material of the parts, and the chemical composition should meet the national standard. And issue a bill of materials.

5. To ensure normal forging temperature, not forging at low temperature or over-burning.


6. The shape of the forgings should be neat and uniform, and no forging defects such as stacking and breaking are allowed.

7. Ultrasonic flaw detection shall be done after rough turning of forgings. Gears shall not exceed φ3 equivalent, and others shall not exceed φ4 equivalent. The inspection report shall prevail.

8. Normalizing after forging.

9. Write the part number with paint on the forging.

The above content is the technical requirements that we need to meet when we carry out gear forging. From the introduction of this article, you should have a general understanding. Gear forgings are still widely used, and are generally used in various machinery. Finally, learning to use gear forgings correctly can extend the actual service life.

Flange shaft

Special alloy forging is much more difficult than ordinary carbon steel and low-alloy structural steel. To produce special alloy forgings with geometric dimensions and metallurgical quality that meet the requirements, corresponding technical measures must be taken according to different characteristics. These measures are mainly Including process measures, forging and die design measures, quality control measures, testing of forging performance (based on selection of thermodynamic parameters), simulation of forging process, first piece trial forging, etc. Among the above measures, the process measures that need to be taken are described as follows:

1. Reasonably select the temperature, heating speed and holding time of the blank into the furnace

For special alloys with low thermal conductivity (especially large-sized billets), they should be heated at a low speed with the furnace or preheated in the furnace at 800 ° C ~ 850 ° C and held for a period of time, rather than directly heated in the furnace at the initial forging temperature, and then heated It is heated to the initial forging temperature or transferred to a high temperature furnace at the initial forging temperature; the holding time at the initial forging temperature depends on the alloy, which is generally several times longer than that of alloy structural steel.

Other blanks of aluminum, magnesium, copper and their alloys with higher thermal conductivity than steel can be directly put into the high-temperature furnace, the heating speed can be accelerated and the holding time can be appropriately shortened.

Harvester pusher

2. Properly select the degree of deformation

In view of the characteristics of high alloying degree of special alloys, serious macrosegregation of ingots and forgings, low plasticity and wide critical deformation range, in the forging process, it is necessary to strictly control the degree of deformation of each fire and even the degree of deformation of each stroke of the equipment (deformation degree If it is too large, it may be forged and cracked, and if the degree of deformation is too small, it may fall into the deformation zone, resulting in local grain growth and uneven structure).

3. Strictly control the final forging temperature

In view of the characteristics of high recrystallization temperature and obvious cold work hardening tendency of special alloys, it is necessary to increase or greatly increase the final forging temperature. The forging temperature is about 300°C higher.

4. Reasonably choose the working speed of the forging equipment

For some special alloys that are sensitive to strain rate and slow recrystallization speed, hydraulic presses, mechanical presses and screw presses with lower loading speed should be selected for forging; for high-speed steels with serious mesh fractures, in order to completely crush them For two-shaped broken objects, a forging hammer with high working speed and strong impact force should be selected for forging.

Other agricultural machinery forgings

5. Reasonable selection of forging equipment

For some special alloys with high deformation resistance, slow recrystallization speed and high final forging temperature, compared with the same size of broken indium and low-alloy structural steel parts, it is necessary to choose the ability to see or load 3 to 5 times or more. Large forging equipment.

In the same case, molybdenum, magnesium and steel and their alloys with low deformation resistance should choose smaller equipment.

6. Protect the blank

In view of the characteristics that alloy element depleted layer and bile layer or absorbing harmful gas are easily formed on the surface of special alloy during heating process, under possible conditions, it should be heated in a protective atmosphere, or a protective coating should be used to protect the blank, for example, to give The blanks are coated with protective glass lubricant.

7. Double lubricate the blank and mold

In view of the characteristics of high deformation resistance of special alloys, large equipment energy (load) and narrow forging temperature range, in addition to lubricating molds in accordance with the routine, the blank should also be protected and lubricated to minimize friction and blank temperature drop, so as to reduce the required tonnage of equipment . It is recommended to use glass shield lubricants to protect and lubricate the blanks when forging superalloys, titanium alloys and stainless steels.

Other agricultural machinery forgings

8. Select the process of forging under compressive stress as much as possible

In view of the characteristics of high alloying degree and low plasticity of special alloys, it is recommended to choose the forging process under compressive stress such as extrusion, closed die satin, and closed upsetting and extrusion on the flat forging machine as much as possible.

9. “Strike while the iron is hot”

In view of the characteristics of high final forging temperature and narrow forging temperature range of special alloys, forging workers are required to be skilled and responsive, and every link from the release of the blank to the transfer to forging must be fast and accurate, and try to shorten the forging pairs as much as possible. The purpose of “strike while the iron is hot”.

10. Strictly implement the preheating system of tools and molds

In view of the characteristics of high final forging temperature, narrow forging temperature range and low thermal conductivity of special alloys, which are sensitive to mold chilling, all clamping dies in contact with forgings must be preheated in strict accordance with regulations.

The above is about the forging process of special alloy forgings. Through the processing of the above process, the plasticity, impact toughness, fatigue strength and durability of the forgings have also been improved, and then the final heat treatment of the parts can be obtained. Good comprehensive properties such as required hardness, strength and plasticity.

Valve holder

Aluminum alloy has begun to be used more and more in the electric vehicle industry. At the same time, aluminum alloy material is also the most widely used metal in all walks of life. The output of aluminum alloy is second only to steel. Aluminum alloys generally have processes such as casting, forging and die casting in the industry.

Different processes meet different application requirements. Among them, aluminum alloy forging has a series of excellent characteristics. After forging, the metal structure of the aluminum alloy can be changed, and the performance of the aluminum alloy can be effectively improved.

Characteristics of aluminum alloy forging

First of all, the internal organization is fine, uniform and defect-free, and its reliability is far away. It can be processed into high-precision forging with complex shapes, and the machining allowance is small, only about 20% of the machining allowance of the aluminum alloy drawing thick plate, which greatly saves man-hours and costs. Second, the thermal conductivity is good.

The forging temperature range is narrow, and the requirements for the forging temperature are always strict. The performance characteristics of heating die forging are that the aluminum alloy does not produce allotropic transformation. It mainly depends on the correct control of the forging mechanical parameters to improve the metal structure, so that the metal streamline is uniformly and continuously distributed along the forging shape. to improve mechanical properties.

Forged aluminum wheels have high density, no porosity, pinholes, and no pores on the surface, and have good surface treatment performance. The coating is uniform and consistent, with high bonding force, and the color is harmonious and beautiful. Forged aluminum wheels have good machinability. It can be seen that forged aluminum wheels have light weight, high specific strength, good toughness, fatigue resistance and corrosion resistance, good thermal conductivity, and easy machining.

Based on the above characteristics of aluminum alloy forging, if the electric vehicle needs to reduce the weight of the whole vehicle, then the steering wheel connecting plate can be made of aluminum alloy forging process, and the rear shock absorber can also be made of aluminum alloy material. Can greatly reduce the weight of the vehicle. The whole front fork of the following products is only 2.85kg, and the rear fork is only 1.35kg.

Aluminum alloy forging process

Forging production occupies a very important position in the industrial industry. Aluminum alloy is also a commonly used material in forging. All kinds of forging that can be forged with low carbon steel can be forged with aluminum alloy. Most of the alloy forged parts are safety parts, and they are mass-produced, so the inherent quality requirements of aluminum alloy materials are very high.

Forged aluminum alloy parts generally go through the following main manufacturing processes: alloy smelting – casting – extrusion – forging – heat treatment – machining. Alloy smelting composition distribution ratio, degassing, filtration, casting reverse segregation, extrusion process quality, forging (aluminum alloy forging) metal streamline, heat treatment temperature, time, grain size control, dimensional accuracy, etc., require a very systematic process control to achieve stability.