Slip-on flanges are available at a lower cost and hence preferred by several contractors. The product holds ample of strength and works even under fatigue conditions as that of the weld-neck flange. The slip-on flange can work well after attaching to the end of a pipe or pipe fitting. The product is fit in easily, or the end of the pipe is set back easily by the thickness of the pipe wall plus 1/8 of an inch. It allows easy installation without putting effort and damaging to the flange face. The outer side of the flange is welded with a fillet weld.

Features of Slip-on flanges

These are flanges available at less cost. They have a low hub as pipe slips into the flange before performing welding. These slip-on flanges are easy to align welded, both internally and externally.

Types of Slip-on flanges

There are various types of Slip-on flanges, including the Slip-On Reducing Flange, raised face slip-on flange, and RTJ slip-on flange. The flange is applicable for reducing the line size and limitation of the space limitations. These flanges work along with the weld neck flange and reducer combination. They are useful when the flow is directed from the smaller size to the larger size. Slip-On flanges are welded internally and externally. The welding offers them the ability to prevent leakage and sufficient strength.

Uses of Slip-on flanges

Slip-on flanges are primarily applicable for fluids working at low pressure. Also, these flanges work well with little chance of leakage. These flanges work well in cooling water lines, firefighting water lines, and low-pressure compressed airlines. Along with this, slip-on flanges are suitable in process lines to maintain the stream of steam, oil, gas, condensates, etc. These flanges are applicable for low pressure and higher temperature system.

Common Uses and Features of Blind Pipe Flanges

Blinds are flanges without a center bore (hole or opening) and are available in both Raised Face (RF) and Flat Face (FF) styles. While most flange types create a connection point that allows the flow of liquid, gas, or air, blind flanges are used to seal the end of a piping system and prevent flow. Blind flanges may be used when testing pipe pressure, to create an access point in a piping system, to temporarily seal a piping system while modifying or repairing the line, or to create a long-term seal to terminate a piping system.

A blind flange is bolted, rather than welded in place. This allows easier access as needed for pipe system upkeep, inspection, or to allow for future expansion. Pairing with a gasket creates a tight seal: The gasket fills the space between the flange faces, which prevents liquid or gas leaks.

How to Choose the Right Blind Flange

Blind pipe flanges may be produced to match bolt hole measurements for slip-on or weld neck flanges, or if needed, can be custom machined to any other specifications. Either way, when purchasing flanges, choose the appropriate flange features, material, dimensions, and class to meet your application needs.

Find the Best Blind Flange Material for the Job

When choosing blind flanges, you must consider the best flange material and dimensions in relation to the piping standards and requirements of your intended application. Generally, your flange material should match the connecting pipe material. The most common blind flange materials are steel and stainless steel.

Steel is preferred for strength. API International stocks blind flanges in both forged and plate steel.

Stainless steel flanges are also available in forged or plate varieties in 304L and 316L. Stainless steel flanges are often preferred for corrosion resistance.

In many cases, import material is acceptable to save on cost – in these cases, the flanges will still meet all the standards for pressure applications. In instances where domestic flanges are specified, API International manufactures flanges meeting “Buy American” or meeting American Iron and Steel Institute (AISI) requirements.

Plate flange vs slip-on flange

A plate flange is a flat, circular disc welded to a pipe’s end enabling the flange to be bolted to another pipe. It is often referred to as flat flange, plain flange and flange slip, etc. Two plate flanges can be bolted together with a gasket in between them, usually used in fuel and water pipelines.

The length of the pipes is not always known while constructing a pipeline. The plates may also be welded with a slight bias to the shaft, allowing two pipes that might not be perfectly matched up to be joined.

Plate flanges have a serrated finish on the inner mating surface allowing the plate to fit within the material of the gasket. In any given dimension, plate flange designs are standardized regardless of the materials used to manufacture them. This ensures it exactly fit a 6-inch (15 cm) black pipe flange to a 6-inch stainless steel flange. This guarantees a perfect seal between the two connecting pipes.