Bend Standards, Cold Bending Methods, and Quality Requirements for Bends
What are the standards for bends?
Many manufacturers often attempt to address this issue before production since the production of bends is typically oriented towards quality. However, without standards to adhere to, it’s easy to create quality imbalances. Here are the standards for bends:
1. Material:
The material should undergo a quality inspection, free from deformities, cracks, and other defects. Fasteners and connectors for bent pipes should not be repaired by welding.
2. Bending Radius:
– Regardless of the number of bends or the bending angle (which should not exceed 180°), the bending radius should be consistent.
– The bending radius should not be less than 2 to 2.5 times the outer diameter of the pipe, and straight sections should not be less than 1.5 times the pipe’s outer diameter.
3. Foundation:
The foundation for bends should be level, solid, and compacted, with the metal base being flat and free from deformities. When the foundation is weak, stress area and stability should be increased.
4. Platform:
The platform should be laid out neatly, with consistent width and length. It should be securely fixed, with no significant holes on the platform surface.
The above points detail the standards for bends from various perspectives. During the production and processing processes, the manufacturing facility should strictly adhere to these standards and control parameters to produce high-quality, long-lasting products.
In the manufacturing of bends, hydraulic drive plays a major role, being powerful and capable of rotating the bends while feeding using servo motor drive, offering high speed and precision. Multiple processing steps can be stored, allowing flexible switching for various product processing, significantly enhancing production efficiency.
In general, cold bending is used for bending bends. In cases where the factory lacks cold bending equipment, hot bending may be permitted, but not for hot bending of gas pipes. Grade 20 steel pipes are not suitable for medium-frequency bending. Stainless steel bends and alloy steel pipes should be cold bent. If hot bending is necessary, care should be taken to avoid carburization during the heating of stainless steel pipes, and highly strain-hardening alloy steel pipes should not be quenched with water. Copper pipes should undergo local annealing before cold bending.
When using bends, the bending radius of the bend is generally not less than three times the pipe’s diameter. In areas where the pipeline layout is relatively compact, smaller bends with an outer diameter less than three times the diameter and a smaller bending radius may be used while ensuring bend quality. Bend operators should be familiar with the structure, performance, operating procedures, and regulations of bends.
The inner diameter of the bend and the core work area should be lubricated adequately. For the core rod’s end sleeve, it should be cut at the end of the core rod, positioned beyond its vertical centerline with the mold.
Quality requirements for bends in the production process generally state that oil-based lubricants for bending are not easy to clean, resulting in significant environmental pollution. Companies will need to employ more means to eliminate these pollutants as the final product’s quality is influenced by oil-based bending lubricants.
In general, in the application of traditional oil-based lubricants, a company’s production efficiency will be significantly limited due to the poor flowability and difficulty of cleaning oil-based lubricants, causing greater pollution to the production environment and workers’ working conditions.
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