Introduction to Welding Neck Flanges - Manufacturer Factory of Wholesale Weld Neck Pipe Flanges

Introducing the Application of Welding Neck Flanges  

50. A welding neck flange is a type of pipe fitting characterized by a neck and circular pipe transition, enabling a butt-welding connection with the pipe. Renowned for its resistance to deformation, excellent sealing properties, and widespread application, it adheres to rigid and elastic standards, featuring a reasonable butt-welding thinning transition. Notably, the gap between the weld crater and the joint surface is substantial, ensuring minimal welding temperature deformation on the joint surface. 

Technical requirements for welding neck flanges

The grade and technical specifications for welding neck flanges must adhere to the corresponding criteria outlined in JB4726-4728. 

50. Grade I forgings for welding neck flanges allow carbon steel and austenitic stainless steel forgings with nominal pressures ranging from 0.25 MPa to 1.0 MPa. 
50. In addition to the provisions, forgings with nominal pressures ranging from 1.6 MPa to 6.3 MPa must comply with the requirements for Grade II or higher forgings. 

Welding neck flanges are typically manufactured using forging or forging rolling processes. However, when selecting steel plates or section steel, the following requirements must be met: 

50. The welding neck flange must undergo ultrasonic flaw detection to ensure no delamination defects. 
50. The steel should be cut into strips along the rolling direction, then bent and butt-welded into a ring shape, with the steel surface forming the cylindrical surface of the ring. Steel plates should not be directly machined into welding neck flanges. 

The outer slope of the neck of the welding neck flange should not exceed 70 degrees. Strict control over the technical parameters of welding neck flanges during production and welding is necessary to ensure they can fully fulfill their role and value in production and application. 

Welding neck flanges are typically manufactured using forgings or forging rolling processes. When selecting steel plates or section steel, it is essential to adhere to the following requirements:

50. The welding neck flange must undergo ultrasonic flaw detection to ensure no defects, such as layering. 
50. The steel should be cut into strips along the rolling direction, bent, and butt-welded into a ring, with the steel surface forming the cylindrical surface of the ring. It is not permissible to machine steel plates directly into welding neck flanges.
50. The butt weld of the ring must be a full penetration weld. 
50. The butt weld of the ring must undergo post-weld heat treatment and be subjected to 100% radiographic or ultrasonic testing. Radiographic testing must comply with level II requirements of JB4730, while ultrasonic testing must meet level I requirements of JB4730. 

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