Stainless Steel Expansion Joints - SS Bellows

Metallic bellows are made from a simple metal tube by creating convolutions on its side. As per the thickness required, plies are added to it. By creating this design, the device expands or compresses according to the temperature changes in the piping lines. This, therefore, accommodates the thermal movements, vibrations, and other mechanical deformations caused by the high temperature and pressure gases. The metals may be of various types of alloys. Stainless steel bellows are made by using stainless steel to create the bellow section.

Kwality Products are a top SS bellows manufacturer who uses high-grade stainless steel such as SS304L, SS316L, SS321, etc to manufacture bellows such as stainless steel vacuum bellows, stainless steel exhaust bellows, etc, as well as are known for producing other types of bellows according to the EJMA standards.

What is SS Bellows?

SS bellows or SS expansion joints are simply put, metal bellows that use a type of stainless steel instead of other metallic alloys. Stainless steel is an alloy that provides excellent structural characteristics such as durability, flexibility, toughness, corrosion-resistant, and so on. As a result, using this to manufacture stainless steel bellows expansion joints make the joint extremely versatile. This provides high strength and flexibility to contain axial movements, as well as small lateral deflections. The stainless steel expansion joints allow a smooth conduit for liquids and gases. The SS bellows also help in resolving minor deviations in the piping system, as well as eliminating residual stresses in the pipeline. The main advantage of this is to absorb thermal movements in the ducts or pipelines due to gases of the highest temperature and pressure.

How to make Stainless Steel Bellows?

The process of manufacturing SS bellows is simple, however, it is extremely necessary to do the process by keeping in mind the several standards and regulations such as the ASME, EJMA, and ISO standards. A good stainless steel bellow manufacturer conforms to these to produce the best quality products.

• Bellow Designs

The first problem SS bellow manufacturer solves is to determine the design parameters. The diameter for the SS expansion joint is determined based on the client's requirement. Depending on the expected life cycle, the thickness of the SS bellows is decided. Based on the thickness, the number of plies required is set. If there is a need to absorb a good amount of vibration in the system, or if there is a requirement for very long life cycles, multiple plies are used. If there are only minimal movements or if infrequent temperature change, as a single-ply may suffice.

• Making the Bellows Tube

Once the design parameters have been determined, the tubes are formed. For this process, stainless steel sheets are sheared as per the required specifications. In the case of multi-ply, the outer sheets are slightly larger than the inner ones. After this, these sheets are then rolled into cylindrical shapes. The tubes are then seam welded in order to avoid splitting. The formed tubes are inspected, cleaned, and then telescopically.

• Forming the Bellows

The next step is to form convolutions on the surface of these tubes. To do this, at Kwality Products, we use hydroforming machines, or mechanical expanders, as per the specification of the required stainless steel pipe bellows. The tube is placed on a die, and hydro pressure is used to mould it into the desired shape, thereby forming corrugations.

• Re-Rolling Process

In this step, the convoluted tubes are further processed and cold worked to its exact shape and geometry as desired by the clients. Failure to do so can lead to poor performance characteristics. In cases of multi-ply, there may be seam spot welding done on the bellow necks.

• Trimming and sizing the Bellows Necks

In the final process, a rotary shear is used to trim the necks of the bellow to achieve the required length and dimensional accuracy. Apart from this, using expanders, the necks are also resized so that they are a perfect fit over the pipe or the flange they are to be fitted. The bellows are then used to assemble the stainless steel bellows expansion joints.

Characteristics Of Stainless Steel Expansion Joints:

• High temperature and pressure resistance
• Vibration absorption
• Compact and space-saving
• Abrasion-resistant
• Corrosion-resistant

Typical Industry Benefits

• Easy maintenance:
  Due to the chemical composition of stainless steel, SS bellows or expansion joints have a shiny smooth finish. As a result, the device is easy to maintain and clean and lasts for years.
• Readjustments:
  Stainless steel bellows can also help resolve minor deviations in the pipe system, as well as reduce residual stress in the connection.
• Wide applications:
  Due to the wide range of design and size available for these, they can be used for a large variety of applications.
• Good absorption capabilities:
  Stainless steel is durable and flexible and has excellent absorption properties that allow them to absorb deformations caused due to thermal expansion and temperature changes.