Threaded Flange

A threaded flange,commonly referred to as a screwed flange or NPT flange,is a non-welded pipe connecting component designed with internal female threads in its central bore.It is engineered to screw directly onto a pipe end equipped with matching external male threads,eliminating the need for welding during assembly.This unique connection mechanism follows standards such as ASME B16.5,with threads typically machined to the NPT(National Pipe Thread)specification per ASME B1.20.1.

Primarily used for small-bore piping systems,threaded flanges are most commonly available in sizes ranging from NPS 1/2 to NPS 4,with 1/2-inch to 2-inch being the most prevalent.They are offered in various pressure classes including Class 150,300,and 600,though their application is generally limited to low-to-medium pressure and low-temperature conditions.The sealing performance relies on thread engagement,often enhanced with PTFE tape or thread sealant,and paired with standard flange faces such as Raised Face(RF)or Flat Face(FF).

Constructed from materials like carbon steel(A105),stainless steel(F304/F316),and alloy steel,threaded flanges adapt to diverse non-corrosive and mildly corrosive environments.Their key advantage lies in weld-free installation,making them ideal for explosive or flammable environments where hot work is prohibited,and for materials with poor weldability.They enable quick assembly,disassembly,and maintenance,ideal for systems requiring frequent access.

However,threaded flanges have limitations:they are not recommended for extreme temperature fluctuations,applications above 260°C or below-45°C,or high-pressure cyclic loads,as thread distortion may cause leakage.They are typically lighter and more cost-effective than socket weld or butt-weld flanges for small-diameter,low-stress systems.

Widely applied in petroleum,chemical,utility,and plumbing systems,as well as in refineries,pump stations,and small-scale process piping,threaded flanges remain a practical choice for safe,efficient,and flexible pipe connections where welding is unsuitable or undesirable.Their simple design,ease of use,and reliable performance under proper conditions solidify their role in industrial piping solutions.