Layout of forging steel workshops in specific steel mills

Design of special steel forge shop (design of special steel forge shop) The use of forging equipment is used to plan billeting or finished products for special steel ingots. The forging steel workshop mainly produces special steel forgings in small batches, various types and larger specifications; and produces some high-alloy steel billets that are difficult to roll, low plasticity, and large deformation resistance; when there are larger forging equipment, some can also be produced Special steel forgings. Forged steel products are used in metallurgy, machinery, electronics, petroleum, chemical, aviation, military and atomic energy industries. A brief history Britain produced the first steam hammer in 1842, bringing casting production into the age of using power. A special steel forging workshop equipped with steam hammers has been built in China. The steam hammer is suitable for the production of thin slabs and small-size forgings, but its ingot shape is small, the product surface is rough and uneven, and the machining allowance is large.

With the development of industry, especially the aviation industry, it is required to use larger specifications of high-alloy steel ingots (nickel-based alloys or titanium alloys) for casting, so as to meet the requirements of product specifications and quality, and at the same time, higher surface accuracy of products is also proposed. Requirements. The steam hammer is no longer used to it. Since the 1950s, Sweden, Britain, Germany, the United States, Japan and other countries have successively selected fast forging presses, which not only have a high number of strokes, but also complete scale precision control and auxiliary process mechanization, as well as co-casting with casting manipulators. Get accustomed to the requirements of rapid casting deformation of larger high-alloy steel ingots, and can obtain high-precision forgings, which improves the yield rate and production rate. Therefore, in the late 1970s, fast forging presses were widely used. For example, in May 1967, the Hagfors factory of Uddehlm-aktiebolag in Sweden installed a 30MN quick forging hydraulic press planned and produced by the Federal German Demark Hydraulic Equipment Manufacturing Company.

The products are cast high-alloy steel, east-west steel, stainless steel, special alloy 180~850mm square billet, 200~900mm round billet and 1850mm wide slab. The material is steel ingots with a weight of 1 to 45t and a diameter of 400 to 1900mm; and an electroslag remelted steel ingots and slabs with a diameter of 600 to 1000mm and a length of 4500mm. During the same period, Austria and the Federal Republic of Germany also developed a precision forging machine for radial casting with mechanical transmission and hydraulic transmission. The horizontal precision forging machine used for special steel production can forge the steel ingots into high-precision square, round or flat bars or shafts, and can reduce the machining allowance of the subsequent process. Precision forging machine casting, the forging is under two-way compressive stress, which can prevent surface cracks; The heat generated by the high-speed deformation can offset the heat radiation heat dissipation, and the steel ingot can be forged into the product in a fire, so the faster forging press is more suitable for the casting of high alloy steel. Generally, the production rate and product yield of precision forging machines can be further improved compared with faster forging presses, but the ingot cross section is restricted by the opening of the hammer. In recent years, the combined operation of fast forging presses and precision forging machines has received attention in special steel mills abroad, which can give full play to the characteristics of fast forging presses for large ingot billeting and precision forging machines to produce large shaft forgings.

China has built and installed 20-25MN fast forging presses and 3.4-14MN precision forging machines around 1980. For example, a steel mill built a modern forging steel workshop with 20MN fast forging presses and 10MN precision forging machines in 1986. Special steel production skills have reached the world’s advanced level. In the 1970s, Austrian Production Technology and Machine Manufacturing Co., Ltd. (GFM for short) developed the precision forging process into a precision forging-rolling process, directly forging and rolling continuous casting billets into bars, with a small footprint and investment Few strengths. Planning planning and product planning The planning and planning of forging steel workshops is generally 20,000 to 100,000 tons per year. The product plan shall distinguish between the representative steel grades, cross-sectional shapes, specification planning, delivery status, and product standards of different types of products. The forging steel workshop mainly produces forging materials, and can also undertake the production of some high-alloy steel rolling billets and some special steel forgings. General products can be divided into carbon structural steel, alloy structural steel, carbon east-west steel, alloy east-west steel (including die steel), spring steel, bearing steel, high-speed steel, stainless steel, and some workshops also have high-temperature alloys and titanium. Alloy or fine alloy, etc. The cross-sections of forging materials are mainly square, round and flat, and the specifications are planned for 80~500mm. Forgings include cake materials, rings, modules and rotational symmetry axes. These must be determined based on market demand. The steel grades, specifications, and output value of the rolled billets are determined according to the requirements of the rolling workshop. Process flow selection The process flow is selected according to the specifications of the produced steel grades and the user’s requirements for the product. 4~14MN precision forging machines. For example, a steel mill built a modern forging steel workshop with 20MN fast forging presses and 10MN precision forging machines in 1986, which enabled China’s special steel production skills to reach the world’s advanced level. In the 1970s, Austrian Production Technology and Machine Manufacturing Co., Ltd. (GFM for short) developed the precision forging process into a precision forging-rolling process, directly forging and rolling continuous casting billets into bars, with a small footprint and investment Few strengths. Planning planning and product planning The planning and planning of forging steel workshops is generally 20,000 to 100,000 tons per year. The product plan shall distinguish between the representative steel grades, cross-sectional shapes, specification planning, delivery status, and product standards of different types of products. The forging steel workshop mainly produces forging materials, and can also undertake the production of some high-alloy steel rolling billets and some special steel forgings. General products can be divided into carbon structural steel, alloy structural steel, carbon east-west steel, alloy east-west steel (including die steel), spring steel, bearing steel, high-speed steel, stainless steel, and some workshops also have high-temperature alloys and titanium. Alloy or fine alloy, etc.

The cross-sections of forging materials are mainly square, round and flat, and the specifications are planned for 80~500mm. Forgings include cake materials, rings, modules and rotational symmetry axes. These must be determined based on market demand. The steel grades, specifications, and output value of the rolled billets are determined according to the requirements of the rolling workshop. Process flow selection The process flow is selected according to the specifications of the produced steel grades and the user’s requirements for the product. 4~14MN precision forging machines. For example, a steel mill built a modern forging steel workshop with 20MN fast forging presses and 10MN precision forging machines in 1986, which enabled China’s special steel production skills to reach the world’s advanced level. In the 1970s, Austrian Production Technology and Machine Manufacturing Co., Ltd. (GFM for short) developed the precision forging process into a precision forging-rolling process, directly forging and rolling continuous casting billets into bars, with a small footprint and investment Few strengths. Planning planning and product planning The planning and planning of forging steel workshops is generally 20,000 to 100,000 tons per year. The product plan shall distinguish between the representative steel grades, cross-sectional shapes, specification planning, delivery status, and product standards of different types of products. The forging steel workshop mainly produces forging materials, and can also undertake the production of some high-alloy steel rolling billets and some special steel forgings. General products can be divided into carbon structural steel, alloy structural steel, carbon east-west steel, alloy east-west steel (including die steel), spring steel, bearing steel, high-speed steel, stainless steel, and some workshops also have high-temperature alloys and titanium. Alloy or fine alloy, etc. The cross-sections of forging materials are mainly square, round and flat, and the specifications are planned for 80~500mm. Forgings include cake materials, rings, modules and rotational symmetry axes. These must be determined based on market demand. The steel grades, specifications, and output value of the rolled billets are determined according to the requirements of the rolling workshop. Process flow selection The process flow is selected according to the specifications of the produced steel grades and the user’s requirements for the product. The planning and planning of the forging steel workshop is generally 20,000 to 100,000 tons of annual output value. The product plan shall distinguish between the representative steel grades, cross-sectional shapes, specification planning, delivery status, and product standards of different types of products. The forging steel workshop mainly produces forging materials, and can also undertake the production of some high-alloy steel rolling billets and some special steel forgings.

General products can be divided into carbon structural steel, alloy structural steel, carbon east-west steel, alloy east-west steel (including die steel), spring steel, bearing steel, high-speed steel, stainless steel, and some workshops also have high-temperature alloys and titanium. Alloy or fine alloy, etc. The cross-sections of forging materials are mainly square, round and flat, and the specifications are planned for 80~500mm. Forgings include cake materials, rings, modules and rotational symmetry axes. These must be determined based on market demand. The steel grades, specifications, and output value of the rolled billets are determined according to the requirements of the rolling workshop. Process flow selection The process flow is selected according to the specifications of the produced steel grades and the user’s requirements for the product. The planning and planning of the forging steel workshop is generally 20,000 to 100,000 tons of annual output value. The product plan shall distinguish between the representative steel grades, cross-sectional shapes, specification planning, delivery status, and product standards of different types of products. The forging steel workshop mainly produces forging materials, and can also undertake the production of some high-alloy steel rolling billets and some special steel forgings. General products can be divided into carbon structural steel, alloy structural steel, carbon east-west steel, alloy east-west steel (including die steel), spring steel, bearing steel, high-speed steel, stainless steel, and some workshops also have high-temperature alloys and titanium. Alloy or fine alloy, etc. The cross-sections of forging materials are mainly square, round and flat, and the specifications are planned for 80~500mm. Forgings include cake materials, rings, modules and rotational symmetry axes. These must be determined based on market demand. The steel grades, specifications, and output value of the rolled billets are determined according to the requirements of the rolling workshop. Process flow selection The process flow is selected according to the specifications of the produced steel grades and the user’s requirements for the product.
The basic production process of forged steel is shown in Figure 1.
        For steel ingots with a unit weight of more than 2t, hot delivery should be considered. For some steel grades, cold-delivered ingots must be peeled first in the steelmaking workshop. After the billet is cast and slowly cooled, it needs to be peeled off by a grinding wheel or pickled (or shot blast) to partially sort out the surface defects, and then sent to the rolling workshop. Forging materials can determine the process flow according to the steel type. Carbon and alloy structural steel forgings can be forged from steel ingots at one time; high-alloy east-west steel, stainless steel and high-speed steel forgings generally require billeting, pickling and surface defects, and then heating and casting. Cold-worked forging materials generally need to be annealed after forging to reduce the hardness and refine the grains. According to user requirements, some forging materials require cut-off and chamfering or rough processing before delivery. The forgings are often annealed after forging. Annealed forgings must be inspected by appearance dimensions, non-destructive testing, and low-magnification arrangements, and some must be inspected for mechanical properties and high-magnification arrangements. For forgings with high requirements for generalized mechanical properties, after rough machining, quenching and tempering treatment is required, and then mechanical properties, low-magnification fracture and high-magnification inspections are arranged. Equipment selection mainly includes forging equipment, heating furnace, heat treatment furnace and finishing equipment. Forging equipment The forging equipment selected by special steel plants includes steam free forging hammers (hereinafter referred to as steam hammers), fast free casting hydraulic presses (hereinafter referred to as fast forging presses) and precision forging machines. The steam hammer can still be used because of its simple structure and low price. However, the 5t steam hammer has tended to be screened because of the noise and sensation; the 3t steam hammer is suitable for producing small thin slabs; the first fire forging material can be arranged with two 3t or 2t steam hammers for joint production. The 30MN fast forging press mainly produces forgings; the 16MN~20MN fast forging press is suitable for billeting of high alloy steel ingots, and produces special steel forgings and forgings such as modules, cakes, rings, and step shafts. The 8MN fast forging press is mainly used for billeting of high-alloy steel ingots and forging materials. 10MN precision forging machine can directly cast round ingots or octagonal ingots with a diameter of less than 550mm into materials in one fire; 8MN precision forging machine can directly cast round ingots or billets with a diameter of less than 400mm into materials; 5MN precision forging machines are mostly used for shafts Casting and production of parts; precision forging machines with mandrel equipment can produce hollow shafts, thick-walled tubes and other products. The mechanical equipment matched with the forging equipment includes a casting manipulator, a steel ingot reversing trolley, and an anvil changing equipment.

The nominal capacity and quantity of forging equipment are selected according to the workshop product plan and the production rate of forging equipment. That is, according to the product category, steel type, specification plan and casting ratio requirements, first determine the ingot type, forging process plan, forging equipment and its nominal capacity; Then according to the product output value and the production rate of forging equipment, when calculating the total annual workbench required by the forging equipment, determine the number of forging equipment according to the following formula: Formula N is the number of forging equipment required for accounting; t is the total annual workbench hours of forging equipment , H; T is the annual time base of each forging equipment, 6500h; η is the equipment load rate, %; N1 is the number of selected forging equipment. Equipment load rate: steam hammer is generally 80% to 85%, at least not less than 60%; casting hydraulic press is generally 70% to 83%, at least not less than 60%; precision forging machine is generally 80% to 85%, at least Not less than 65%. Examples of production capabilities of steam hammers, fast forging presses and precision forging machines are shown in the table. In the case of multi-fire casting, a chamber heating furnace can be added to cooperate with successive heating furnaces. The quick forging hydraulic press of 12.5MN and the precision forging machine of more than 10MN should be equipped with ring furnace. In order to satisfy the production of a small number of large-size forgings, 1 to 2 car bottom heating furnaces should be equipped. When the rapid forging hydraulic press is produced with multiple fire castings, it should also be equipped with a chamber heating furnace. When using steel ingots above 2t as the material, the workshop should set up a car bottom type preheating furnace, so that the shipped hot steel ingots can be put into the furnace in time for heat preservation, and it can also be used for preheating of cold steel ingots. The mechanical equipment outside the heating furnace mainly includes pusher, tapping machine, ingot transporter, and (without) rail loading and unloading machine. Heat treatment equipment is selected according to the heat treatment process of the product and user requirements. Car bottom heat treatment furnace is generally used, and the length of the trolley is considered according to the length of the forging. The width of the trolley is generally 1.5-2m, and the length of the trolley is generally 4-11m. The area of ​​the trolley can be calculated as follows: where F is the total area of ​​the heat treatment trolley, m2; 1.1 is the repetitive treatment coefficient; Q is the annual heat treatment capacity of forgings, t; 7700 is the annual working time of the heat treatment furnace, h; f is the output rate of the heat treatment furnace, generally 50~75kg/(m2•h). After the total area of ​​the heat treatment trolley is determined, the scale and the number of seats of the car bottom heat treatment furnace are selected according to the production requirements. Finishing equipment includes pickling, shot blasting, and defect grinding equipment. Pickling or shot blasting is used to trim the oxide scale on the surface of the forging material to expose its shortcomings for further grinding and finishing. Because the shot blasting machine has a high production rate and no waste acid wastewater treatment problem, it has gradually replaced pickling. For the peeling and finishing of square, round, and flat steel, grinding wheel grinders are often used, and lathes are also used. The internal shortcomings of forging materials generally use ultrasonic flaw detectors. There are ultrasonic flaw detectors for bars, square slabs and cakes. Circular sawing machine and band sawing machine are generally used for sample cutting and cut-to-length cutting of forging materials.

In addition, a pressure straightening machine should be installed to straighten the bar that exhibits twists after heat treatment. The lifting weight of the crane in the workshop is mainly determined according to the demand for the stack of forgings or slow-cooling boxes produced in the workshop and the demand for equipment maintenance. The lifting weight of the crane in the fast forging press and the precision forging machine workshop should be considered for the lifting weight of the largest forging machine component; the lifting weight of the crane in the forging hammer workshop should first consider the lifting weight of the casting manipulator. The crane in the forging section adopts the heavy duty system, and the other sections use the intermediate working system. The service plan of each crane is 40-50m. Workshop composition and placement The forging steel workshop is composed of materials, casting, heat treatment, finishing, products, machine repairs and other parts. A single forging steel workshop can be placed adjacent to the auxiliary workshop. Regarding more than two forging workshops, they can be arranged separately, taking into account the commonality of materials, product storage, and subsequent processes. For example, the factory building of a forging steel workshop is arranged, the materials are transported in and the products are transported out, the operation between the various processes is dredged, and the forging equipment and heating furnace are arranged compactly and reasonably. The main section and the auxiliary section are very close, and the material activities do not interfere with each other. This can reduce the auxiliary operation time, which is conducive to the casting of multi-fire high-alloy steel. Two or more presses can be operated independently or jointly.

The lifting weight of the crane in the forging hammer workshop is primarily to consider the lifting weight of the casting manipulator. The crane in the forging section adopts the heavy duty system, and the other sections use the intermediate working system. The service plan of each crane is 40-50m. Workshop composition and placement The forging steel workshop is composed of materials, casting, heat treatment, finishing, products, machine repairs and other parts. A single forging steel workshop can be placed adjacent to the auxiliary workshop. Regarding more than two forging workshops, they can be arranged separately, taking into account the commonality of materials, product storage, and subsequent processes. For example, the factory building of a forging steel workshop is arranged, the materials are transported in and the products are transported out, the operation between the various processes is dredged, and the forging equipment and heating furnace are arranged compactly and reasonably. The main section and the auxiliary section are very close, and the material activities do not interfere with each other. This can reduce the auxiliary operation time, which is conducive to the casting of multi-fire high-alloy steel. Two or more presses can be operated independently or jointly. The lifting weight of the crane in the forging hammer workshop is primarily to consider the lifting weight of the casting manipulator. The crane in the forging section adopts the heavy duty system, and the other sections use the intermediate working system. The service plan of each crane is 40-50m. Workshop composition and placement The forging steel workshop is composed of materials, casting, heat treatment, finishing, products, machine repairs and other parts. A single forging steel workshop can be placed adjacent to the auxiliary workshop. Regarding more than two forging workshops, they can be arranged separately, taking into account the commonality of materials, product storage, and subsequent processes. For example, the factory building of a forging steel workshop is arranged, the materials are transported in and the products are transported out, the operation between the various processes is dredged, and the forging equipment and heating furnace are arranged compactly and reasonably. The main section and the auxiliary section are very close, and the material activities do not interfere with each other. This can reduce the auxiliary operation time, which is conducive to the casting of multi-fire high-alloy steel. Two or more presses can be operated independently or jointly.
The process layout of a factory is shown in Figure 2

Primary technical economic indicators The planning and planning of forging steel workshops is generally an annual output value of 20,000 to 100,000 tons (the output value of forging materials accounted for about 72%, and the output value of forging billets accounted for about 28%). Different steel products have different consumption of ingots. The consumption of steel ingots per ton of forging billets of carbon structural steel, carbon east-west steel, and alloy structural steel is generally about 1200kg/t, and the consumption of ingots per ton of forging products is generally about 1230kg/t; spring steel, ball bearing steel, The consumption of ingots per ton of forging billets of stainless steel and alloy steel is generally about 1240kg/t; the consumption of ingots per ton of forging products is generally about 1350kg/t; the consumption of ingots per ton of high-speed steel and high-temperature alloy forging billets is generally about At 1360kg/t, the consumption of steel ingots per ton of forgings is generally about 1430kg/t; the consumption of steel ingots per ton of forgings is generally about 1500kg/t. The power consumption per ton of forged steel is generally about 250kw•h/t; the fuel consumption per ton of product is generally about 18000MJ/t; the steam consumption per ton of product is generally about 3700kg/t; the water consumption per ton of product is generally about 20000kg/t; the annual output value of the workers in the forging workshop is generally about 80t/(a•person).

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