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We provides ASME Code and Non Code Industrial flanges for the Petrochemical, Process, & Waterworks industries. ANSI, API, AWWA pipe flanges in carbon, stainless, alloys and chrome steel. Weld Neck, Slip on, Blind, Threaded, socket weld, Lap Joint, Orifice Flanges in sizes 1/2" to 198".

Welding Neck Flanges:
The welding neck flange

is normally referred to as the "high hub" Flange. It is designed to transfer stresses to the pipe, thereby reducing high stress concentrations at the base of the Flange. The welding neck flange is the best designed butt-welded flange of those currently available because of its inherent structural value. It is expensive because of the design.
Threaded (Screwed) Flanges:
The threaded flange is similar to the slip-on flange, but the bore is threaded. Its chief merit is that it can be assembled without welding, explaining its use in low pressure services at ordinary atmospheric temperatures and in highly explosive areas where welding create a hazard.
Slip-On Flanges:
The slip-on flange has a low hub because the pipe slips into the flange prior to welding. It is welded both inside and out to provide sufficient strength and prevent leakage. Slip-on flanges are all bored slightly larger that the O.D. of the matching pipe. They are preferred over welding neck flanges by many users due to their lower initial cost, but final installation cost is probably not much less than that of the welding neck flange because of the additional welding involved.

Thanks for sharing.
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