What are the production characteristics of large forgings?
2022-06-01
The production characteristics of large forgings are: shape large weight, high quality requirements, product varieties, single, small batch production, product production cycle is long.
1. Wide range of products
Usually, the forgings produced by free forging hydraulic press with 10 MN and above are called large forgings, equivalent to shaft forgings with a single weight of more than 5T, cake forgings with a single weight of more than 2T. The main varieties of large forgings include:
1) Forging of rolling machine, such as cold and hot rolls, etc.
2) Forging equipment forgings, such as columns and cylinder blocks of hydraulic press.
3) Thermal power forgings, such as generator rotor, retaining ring, turbine rotor, impeller, etc.
4) Water and electricity forgings, such as the main shaft of water turbine generator, mirror plate, etc.
5) Forgings for nuclear power plant, such as pressure shell, evaporator barrel, tube plate, etc.
6) Petrochemical pressure vessel forgings, such as cylinder, flange and sealing head of high pressure vessel.
7) Marine forgings, such as stern shaft, intermediate shaft and crankshaft of Marine engine, etc.
8) Cement equipment forgings, such as ring teeth, etc.
9) Forgings of mine lifting equipment, such as spindle, etc.
10) Inner and outer rings for oversized bearings.
11) Modules for die forging hammer and press.
12) Military forgings, such as gun barrel, pressure shell of nuclear vessel of nuclear submarine, turbine disc of jet engine, etc.
13) Various axles of railway rolling stock.
14) Spindle for large AC and DC motors.
The above range of forgings, a wide variety, specifications are different, each has its own characteristics. This brings great difficulty to production technology preparation and production plan management.
2. Single piece and small batch production
Heavy machinery, especially large steel rolling and forging equipment, are single-piece production, large forging blanks are also one-time single-piece production. A piece of a set of technology, there are many special technology equipment, less chance to reuse. Some large forgings belonging to the "tool" nature, such as cold and hot rolls used in metallurgical plants, are also produced in small batches. Large forgings production, need a successful. This requires full technical preparation before production, including all kinds of process validation and experimental research, time-consuming and costly, high production cost.
3. The technical preparation is complicated and the production cycle is long
Single or small batch production of large forgings, production preparation complex, long production cycle.
1) The preparation of metallurgical fittings is complicated. For example, the rotor of a 600MW generator, from the steel ingot mold of smelting and casting, lifting sprig, transportation auxiliary, to the large auxiliary for forging, heat treatment and rough processing, its total weight, production time, production cycle and production cost greatly exceed the production of basic parts.
2) The research of various topics and the formulation and implementation of the process plan before the production of large forgings have a long cycle.
3) Due to the large weight and shape of the large forgings, the production cycle is long. Including charge preparation, smelting, ingot, forging, first heat treatment, second heat treatment, rough processing and various testing.
4. The products require high quality and are difficult to produce
Large forgings generally require high quality and harsh technical conditions. This is especially true for power station forgings. It has very strict standards and requirements for the chemical composition (including gas content), mechanical properties (tensile and impact properties), non-destructive testing (ultrasonic and magnetic particle testing), metallographic testing (grain size, inclusion) and size and surface roughness of steel.
The production of large forgings from smelting, ingot, forging, forging heat treatment to performance heat treatment, to go through a lot of processes, each process affects the quality of forgings, a little deviation may cause defects, so it is difficult to produce
1. Wide range of products
Usually, the forgings produced by free forging hydraulic press with 10 MN and above are called large forgings, equivalent to shaft forgings with a single weight of more than 5T, cake forgings with a single weight of more than 2T. The main varieties of large forgings include:
1) Forging of rolling machine, such as cold and hot rolls, etc.
2) Forging equipment forgings, such as columns and cylinder blocks of hydraulic press.
3) Thermal power forgings, such as generator rotor, retaining ring, turbine rotor, impeller, etc.
4) Water and electricity forgings, such as the main shaft of water turbine generator, mirror plate, etc.
5) Forgings for nuclear power plant, such as pressure shell, evaporator barrel, tube plate, etc.
6) Petrochemical pressure vessel forgings, such as cylinder, flange and sealing head of high pressure vessel.
7) Marine forgings, such as stern shaft, intermediate shaft and crankshaft of Marine engine, etc.
8) Cement equipment forgings, such as ring teeth, etc.
9) Forgings of mine lifting equipment, such as spindle, etc.
10) Inner and outer rings for oversized bearings.
11) Modules for die forging hammer and press.
12) Military forgings, such as gun barrel, pressure shell of nuclear vessel of nuclear submarine, turbine disc of jet engine, etc.
13) Various axles of railway rolling stock.
14) Spindle for large AC and DC motors.
The above range of forgings, a wide variety, specifications are different, each has its own characteristics. This brings great difficulty to production technology preparation and production plan management.
2. Single piece and small batch production
Heavy machinery, especially large steel rolling and forging equipment, are single-piece production, large forging blanks are also one-time single-piece production. A piece of a set of technology, there are many special technology equipment, less chance to reuse. Some large forgings belonging to the "tool" nature, such as cold and hot rolls used in metallurgical plants, are also produced in small batches. Large forgings production, need a successful. This requires full technical preparation before production, including all kinds of process validation and experimental research, time-consuming and costly, high production cost.
3. The technical preparation is complicated and the production cycle is long
Single or small batch production of large forgings, production preparation complex, long production cycle.
1) The preparation of metallurgical fittings is complicated. For example, the rotor of a 600MW generator, from the steel ingot mold of smelting and casting, lifting sprig, transportation auxiliary, to the large auxiliary for forging, heat treatment and rough processing, its total weight, production time, production cycle and production cost greatly exceed the production of basic parts.
2) The research of various topics and the formulation and implementation of the process plan before the production of large forgings have a long cycle.
3) Due to the large weight and shape of the large forgings, the production cycle is long. Including charge preparation, smelting, ingot, forging, first heat treatment, second heat treatment, rough processing and various testing.
4. The products require high quality and are difficult to produce
Large forgings generally require high quality and harsh technical conditions. This is especially true for power station forgings. It has very strict standards and requirements for the chemical composition (including gas content), mechanical properties (tensile and impact properties), non-destructive testing (ultrasonic and magnetic particle testing), metallographic testing (grain size, inclusion) and size and surface roughness of steel.
The production of large forgings from smelting, ingot, forging, forging heat treatment to performance heat treatment, to go through a lot of processes, each process affects the quality of forgings, a little deviation may cause defects, so it is difficult to produce
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