Technical requirements for pipe flange forgings (including forged and rolled parts)

Flanges are a type of disc-shaped component, most commonly used in pipeline engineering, and are typically paired together. In pipeline engineering, flanges are mainly used for connecting pipelines. Install a flange plate on the pipeline that needs to be connected. For low-pressure pipelines, Threaded Flanges can be used, and for pressures above 4 kilograms, welded flanges can be used. Add sealing points between the two flanges and tighten them with bolts. Flanges with different pressures have different thicknesses and use different bolts. When connecting water pumps and valves to pipelines, the corresponding flange shapes are also made for the parts of these equipment, also known as flange connections. Any connecting parts that are bolted together in two planes and enclosed at the same time are generally referred to as "flanges", such as the connection of ventilation ducts, which can be called "flange type parts". However, this connection is only a partial part of a device, such as the connection between a flange and a water pump, so it is not appropriate to call the water pump a "flange type component". Smaller components such as valves can be called "flange parts"

Technical requirements for Pipe Flange forgings (including forged and rolled parts).

The grade and technical requirements of forgings (including forged and rolled parts) shall comply with the corresponding requirements of JB4726-4728.

1. Carbon steel and austenitic stainless Steel Forgings with a nominal pressure PN of 0.25MP-1.0MPa are allowed to use Grade I forgings.

2. Except as provided below, forgings with a nominal pressure PN of 1.6MPa-6.3MPa shall comply with the requirements of Grade II or higher forging grades.

3. If one of the following conditions is met, it should meet the requirements of III and forgings: (1) forgings for flanges with nominal pressure PN ≥ 10.0MPa; (2) Chromium molybdenum Steel Forgings with nominal pressure PN>4.0MPa; (3) Ferritic Steel Forgings with nominal pressure PN>1.6MPa and working temperature ≤ -20 degrees Celsius.

Neck butt welding, neck flat welding, socket welding, and Threaded Flanges are generally made using forging or rolling processes. When using steel plates or sections for manufacturing, the following requirements must be met:

1. The steel plate should undergo ultrasonic testing and have no delamination defects;

2. It should be cut into strips along the direction of steel rolling, bent and welded into a circular ring, and the surface of the steel should form a cylindrical ring. Steel plates shall not be directly machined into necked flanges;

3. The butt weld of the circular ring should be a full penetration weld;

4. The butt welds of the circular ring should undergo post weld heat treatment and undergo 100% radiographic or ultrasonic testing, with radiographic testing meeting the Level II requirements of JB4730 and ultrasonic testing meeting the Level I requirements of JB4730.

The outer slope of the neck with neck flat welding flange, socket welding flange, and Threaded Flange should not exceed 7 degrees.