Circular Hollow Sections
General information on circular hollow sections
Circular hollow sections (CHS) are manufactured to be seamless or welded. CHS have advantageous static and constructive characteristics: While square and rectangular hollow sections have the advantage of being stronger in bending, a round hollow section has more stiffness in twisting. CHS are very versatile, which has lead them to become a vital component in most industrial and nonindustrial industries. Apart from serving their original purpose as a conduit pipe -transporting gasses and liquids over long distances- CHS are nowadays also used as supporting or design elements in construction.
How are circular hollow sections manufactured?
Due to their popularity many ways of manufacturing CHS exist, the most common of which have been listed and described below.
Seamless circular hollows are commonly manufactured by hot rolling, during which steel pipes are given their shape in two basic steps: The first step involves the piercing of steel blocks and the resulting ingots being heated to about 1300°C. After heating, the hot ingots are pressed through a matrix, forming an initial steel casing. Any subsequent steps turn initial casings into finished steel tubes through further rolling procedures.
The three processes listed below are most commonly used to achieve the above:
- Pilger(ing) process
- Continuous mandrel rolling process
- Push-pull technique
Welded hollow sections are manufactured from flat steel. Depending on the desired circumference and measurements, different types of steel sheets are used in the manufacturing process. The seams of welded circular sections can either be fused electrically or with the aid of a gas flame. The seam usually runs parallel to the axle of the pipe, however exceptions such as spirally welded pipes do exist. When manufacturing CHS, high frequency resistance welding or submerged-arc welding are commonly applied.
Which industries utilise CHS in their manufacture?
Circular hollow sections are commonly used in the following industries:
- boiler construction
- car manufacturing
- electrical engineering
- construction
- chemical and petrochemical industries
- furniture manufacturers
- oil industry
What are the benefits of CHS?
Kloeckner customers value CHS for their versatility, with a few standout characteristics being deemed particularly desirable:
- high carrying capacity
- construction advantages
- easy manipulation
- aesthetic appeal
- anti-corrosion treatment
- fire resistance treatment