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Currently pipeline automatic welding become more and more popular, especially for long distance project, it has the advantages of high efficiency , reliable welding quality, also easy welder training etc.

There are two types of automatic welding for pipe:

Option 1: Automatic internal welding for root pass, then follow by automatic orbital welding for others including filling and capping passes. Comparing to orbital welding , internal welding is faster and more reliable. it does not require backing material for root, for a long pipeline project, internal welding is better choice.

Option 2: Automatic orbital welding for all passes, it also two ways to go

A. Internal line up clamp with backing when automatic orbital welding, copper shoes are the most popular backing which are usually adopted by contractors, it is very helpful for root pass profile with very low repair rate. Anyhow some project owners concern about the copper contamination, however per studies domestically and overseas, the welding bead copper content is very low, even lower than copper content in base material.

Copper shoes consumption would be another issues, however if adopt PGMAW for root and program correctly with right setting including current, voltage etc , the experienced welders should get over 500 joints on a set of coppers and that can be considered wear and tear.

Copper Shoes Condition After 70 Welding Joints

B. Internal line up clamp without backing, this is called "one-side welding with back formation". In this case, RMD / STT/ Rootwise/CMD welding would be considered, the welding time is longer than type A, in addition per project data, the repair rate is higher, it also require high skilled welders.

Remarks: RMD from Miller, STT from Lincoln, Rootwise from Kemppi, CMD from Fronius

The essential steps and equipment components required of automatic welding system:

1. The first and most important factor in providing a high accuracy pipe bevel, pipe facing machine is specially for pipe end preparation prior to automatic welding

Automatic welding have strict requirements for pipe bevel, if bevel requirements are not met, it would lead to welding failure. Hence when we choose pipe facing machine, we must focus on whether the pipe facing machine can make consistent bevels which dimensions and surface quality can be fully ensured, especially at the conditions of big pipe diameter and thick wall.

As high speed rotation equipment, pipe facing machine have high requirement for parts accuracy and production process control , for example we have over 50 processes to ensure high precision of main shaft.

2. When we choose Option 2 type A, then internal line up clamp with copper shoes are required. Then we need to check whether the copper shoes fit each other without any gap and fully contact against inner wall at expanding condition, copper shoes life time is another factor to be considered. High quality copper shoes shall ensure no adhesion with welding bead and long lift time, the copper shoe consumption can be decreased hugely

Deping Technology specialize in pipeline automatic welding and associated equipment, Feel free to contact us if you have any question.