English
English
The quality of forging processing is the core that determines the performance, reliability, and service life of forgings. Its quality is not determined by a single factor, but by the comprehensive influence of multiple key links in the entire process from raw materials to processing.
1、 The intrinsic quality of raw materials
This is the foundation and starting point of forging quality.
Chemical composition: The elemental composition of raw materials must meet the standards. Trace harmful elements (such as excessive sulfur and phosphorus content) can cause thermal or cold brittleness, seriously affecting forging performance and finished product toughness.
Metallurgical defects: If there are serious non-metallic inclusions, residual shrinkage cavities, porosity or segregation in the raw materials, they are not only difficult to eliminate during the forging process, but may also be stretched and expanded, becoming crack sources or weak performance areas.
Original organization and state: The original grain size and uniformity of the material directly affect its forging plasticity. Coarse or uneven organization can reduce the material's ability to deform and increase the risk of cracking.
2、 Control of forging process
This is a direct and critical link that affects the quality of forging.
Heating process:
Heating temperature: If the temperature is too low, the material has poor plasticity, high deformation resistance, and is prone to cracking; If the temperature is too high, it is easy to cause overheating (coarse grains) or even overburning (oxidation and melting of grain boundaries), leading to the scrapping of forgings.
Heating speed and uniformity: Heating too quickly or unevenly can generate huge thermal stresses inside the material, which can be combined with subsequent forging stresses and cause cracking. This is particularly crucial for high alloy steel and large section billets.
Insulation time: Insufficient time, the heart is not fully heated; If the time is too long, it will lead to grain growth and severe oxidation and decarburization on the surface.
Deformation process:
Deformation (forging ratio): Adequate deformation is the guarantee for breaking the as cast structure, forging internal defects, refining grains, and forming dense fiber flow lines. If the deformation is insufficient, the organizational improvement will be insufficient and the performance will not meet the requirements.
Deformation speed and temperature: Forging within an appropriate temperature velocity window can activate dynamic recrystallization of the material and obtain microstructure. The final forging temperature is particularly important. If it is too high, it will cause grain growth, while if it is too low, it will enter the cold deformation zone, which may result in work hardening or even cracks.
Uniformity of deformation: Unreasonable mold design or improper operation can lead to uneven metal flow, resulting in defects such as folding, flow through, eddy currents, and uneven organizational properties.
3、 Factors of mould and equipment
Mold design and manufacturing quality: The rationality of the mold cavity determines the filling and flow mode of the metal. Rough mold cavity, small corner radius, and improper draft angle can easily lead to incomplete filling, folding, cracking, or difficult demolding of forgings. The strength, hardness, wear resistance, and preheating state of the mold itself also directly affect the accuracy and surface quality of the forging.
Equipment capability and status: The tonnage, stiffness, accuracy, and stability of forging equipment (forging hammers, presses, etc.) are crucial. Insufficient equipment tonnage can lead to insufficient deformation and penetration depth, resulting in poor core quality; Poor equipment accuracy and clearance between guide rails can lead to forging errors and dimensional deviations.
4、 Cooling and subsequent heat treatment
The treatment after forging is the final step towards the door.
Cooling process: Cooling after forging is the starting step of "subsequent heat treatment". Improper control of cooling rate (such as rapid cooling of high carbon high alloy steel) can generate tissue stress and thermal stress inside the forging, leading to the formation of white spots, cracks, or abnormal hard structures.
Heat treatment process: The final performance of forgings is mainly obtained and stabilized through heat treatment (annealing, normalizing, quenching and tempering, etc.). Improper heat treatment processes (such as incorrect heating temperature, insulation time, and selection of cooling medium) can lead to inconsistent hardness, inadequate strength and toughness, abnormal microstructure (such as overheating, decarburization, quenching cracks), etc., resulting in the failure of previous forging achievements.
5、 Operation and management level
This is the 'soft factor' that runs through the entire process.
Operational standardization: Workers' operational skills and experience directly affect the accuracy of process execution. Including visual judgment of temperature, control of impact force and rhythm, timing of lubrication and cooling, etc.
Process inspection and control: Strict process quality control (such as first article inspection, patrol inspection, key parameter recording) can promptly identify and correct problems, avoiding batch quality accidents.
In summary, the quality of forging processing is a systematic engineering. It is like a chain that is interlocked, with raw materials as the foundation, heating and deformation processes as the core, mold equipment as the guarantee, cooling and heat treatment as the shaping, and the management and control of the entire process as the link that connects and strengthens it. Any negligence or improper control in any link may result in defects or substandard performance of forgings, affecting their safety and lifespan during use. Therefore, high-quality forgings are inevitably the result of the comprehensive synergy of technology, process, and management.
