There’re several ways to construct a pipeline:

Hot rolling is a method to build semi-finished product of pipeline. The steel is formed to become flat product which is used to built a tube/pipeline later on. This method use hot stell and a roller on top and bottom of it and turn the hot steel become thinner and thinner until meet the desired thickness.

This method is used to turn flat product from the previous method, into sheet steel. This method takes a few times of cold rolling until the flat product become sheet steel. The next step is heating/annealing the sheet steel to make it softer and terminated with temper rolling to “ironing” the steel.

Hot tube piercing is a method to build the seamless pipeline. The first step is heating the steel and then a pierce is pierced into the hot steel.The pierce will make a long hole inside the steel. To make the outside diameter and wall thickness, this method is followed with hot tube rolling. It will reduce the wall thickness without reducing the outside diameter.

This method is used to make a pipeline with big outside diameter. It use material from the previous method which is sheet steel from hot rolling. After that, the sheet steel is formed into tube and sealed bby welding. Due to it’s way of welding, this method is divided into two:

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Source:

Slide presentation of Construction Material for Marine Environment lecture. Ocean Engineering, ITB. 2013.