Pipeline all position automatic welding construction method

In the construction of pipeline engineering, welding quality is one of the most important links to ensure the quality of the project, and welding efficiency also directly affects the construction progress, that is, the quality and progress of the project depends on the welding quality and welding progress to a large extent. With the continuous development of oil and gas pipelines to large caliber, long distance, high strength and high pressure, the difficulty of welding is getting greater and greater, and the requirements for welding quality are also getting higher and higher. It is difficult to meet the above requirements by manual arc welding and semi-automatic welding with flux-cored wire. The all-position automatic welding of pipelines is a new welding process that can meet the requirements.

Automatic welding of all positions of the pipeline is that the pipe is fixed, and the welding trolley is rotated around the pipe to realize the welding of all positions of the pipe (flat, upright and upright). The welding process is completed by machinery and microcomputer, and is less affected by human factors, so the pipeline all-position automatic welding has the advantages of good weld quality and high welding efficiency.

Construction characteristics

Using STT gas protected semi-automatic welding process with good performance, strong applicability to the pipe mouth characteristics, welding root welding bead. Using the automatic welding of all positions of the pipeline, the characteristics of high welding efficiency, welding filler and cap weld. This process has the following characteristics:

1. STT gas protected semi-automatic welding process characteristics

(1) Starting arc is easy.

(2) Stable arc combustion.

(3) Welding smoke and noise is small.

(4) Minimal splash.

(5) The inner weld bead is beautiful.

(6) Easy to operate.

(7) Low welding cost.

(8) Higher welding efficiency (compared with manual arc welding and argon tungsten arc welding).

(9) Poor wind resistance (compared with manual arc welding).

(10) Especially suitable for the welding of the pipe root weld, but also suitable for the welding of other welding joints.

2. Process characteristics of pipeline all-position automatic welding equipment

(1) Welding process parameter input device (Newton information package), can store multiple groups of welding process parameters to apply to the needs of multiple welding machines and different specifications of steel pipes.

(2) Most of the welding process parameters of the welding equipment are input by the welding process parameter transmitter, and the welder cannot modify them (welding process parameters are input by welding technicians), which ensures the accuracy of welding process parameters.

(3) Welding arc combustion is relatively stable.

(4) High welding productivity, compared with manual arc welding can be increased by 2 to 5 times.

(5) Beautiful weld forming, good internal quality.

(6) CO2 gas or gas mixture (Ar+CO2) can be used as a protective medium.

(7) Applicable pipe diameter φ ≥325mm, applicable pipe wall thickness δ ≥5mm. The larger the pipe diameter and the thicker the wall thickness, the better the economic benefit.

Scope of application

This method is suitable for welding of oil, gas and water pipelines of low carbon steel and low alloy steel.

Technological principle

1. STT welding process principle

STT welding power supply is a kind of CO2 gas protected semi-automatic welding with surface tension as the main transition force of droplet.

The STT welding power supply has waveform control function, depending on the different transition process of the droplet. Control welding current and arc voltage waveform. The welding power supply can automatically adjust the welding current and arc voltage to achieve the instantaneous heat required by the arc. Ensure stable combustion of welding arc and control weld formation effectively.

2. Pipeline all position automatic welding working principle

WINCOO pipeline all-position automatic welding machine is an automatic welding equipment specially used for pipeline welding. It uses a solid core wire (φ0. 8 ~ φ1. 0), the protective gas used is c02 or a mixture of gases (CO2+Ar). The welding direction is downward welding. The welding process parameters such as wire feed speed, welding speed and swing frequency are input by the welding process parameter input, and the welder cannot modify it (or can only modify a certain parameter in a certain range) to ensure the consistency of the welding process parameters of each welding machine and each welding joint. Thus, the uniformity of welding quality of each weld is ensured, and the purpose of ensuring welding quality is achieved.

The welding equipment is suitable for welding in the form of narrow gap groove. The narrow gap groove has the following advantages:

(1) The welding joint has a small heating range and a small welding heat affected zone.

(2) Small welding deformation and stress.

(3) Good organization and performance of the weld.

(4) Save welding materials.

(5) High welding efficiency.

This welding equipment is suitable for welding of various groove forms. When used for the welding of V-shaped bevelings, in addition to the low welding efficiency of narrow gap bevelings (which can still reach 2 to 5 times of manual electric welding), other welding advantages are still prominent.

WINCOO ENGINEERING CO.,LTD provides professional All position TIG closed tube to tube welding machine. Please visit our website:www.sino-wincoo.com for more information.