Problems with national standard valve flange specifications
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1. For valves that comply with national standards nowadays, some have integral flanges while others have flanges that are first screwed in before being welded. Are the standards for flanges all based on integral flanges? 2. Terms like butt weld flanges, necked butt weld flanges, necked socket weld flanges, threaded flanges, and so on – do these all refer to flanges used for connecting pipes?
Is no one going to answer me? It’s so quiet here:hug:
1. An integral flange refers to a connection flange that is formed as part of the equipment itself, such as flanges used to connect valves that are cast or forged. 2. Flanges such as flat-weld flanges and necked butt-weld flanges can also be used at the connection ends of equipment; for example, flanges that weld the connection end to the valve body are used to connect valves. 3. Flanges for pipes generally include flat welding flanges, necked flat welding flanges, necked butt welding flanges, and socket welding flanges; integral flanges are not suitable for pipes.
Are the dimensional standards for the flange on that valve based on those of a standard integral flange?
For national standard valves with flange welding, which standard should be followed? I’ve seen some cases where the threads are screwed in first and then welded together
It is recommended to refer to JB/T90-1994
National standard flanges are generally manufactured in accordance with HG20592 or GB/T9115. You mentioned machining threads and then screwing the flange in before welding it. That appeared as a forging on the high-pressure valve. They are afraid it might leak if not processed properly. So, first, machine a thread. Screw the flange back in and weld it in place. This is safer. There is another type as well, which are flanges used in the chemical industry. High-pressure angle-type stop valve. The flange is where the threads are screwed in. The flanges are sealed to each other with lens gaskets.
If welding is used, that standard for flange plates can be applied