100% quality and 100% repeatable welds

A requirement in all manufacturing systems is pipeline quality. The media has to flow smoothly. Welded pipes are used in pharmaceutical, food, chemical and also in petrochemical industries, which is why the welds on the inner surface have to be fully welded over, and their colour has to match the required colour scale. Such pipelines are free from dirt, micro-organisms and various solids; the welding previously mentioned significantly reduces the impact of corrosion.

 

The process of orbital welding ensures 100% repeatable quality of welded joints. The root and crown shape as well as the desired colour of the welded joint can be achieved within the required tolerances: no pits, dents, bumps and areas that would allow the formation of harmful microorganisms.

 

Inverters (pulsating current transistors) provide the best results in addition to the repeatability and quick changes with regard to deviating parameters when they are being preprepared. Pulsating current enables a quality welded joint without slag inclusions, excessive crown or root convexities and concavities.

 

Orbital welding is based on the TIG process – a process based on pulsating weld current. During this process a welder cannot directly influence the welding process as it is guided by a microprocessor in a confined space called the welding head. For that purpose a welding programme is created prior to welding, comprising all the elements for a perfect weld. The settings for the programme are based according to the areas used as the pathway for the tungsten electrode. The pipe diameter is usually divided into four areas with different parameters in order to achieve the right welding over with regard to the weld pool movement. The various welding parameters are specifically adapted to individual areas.

 

We partly use the manufacturer’s instructions to correctly set welding parameters, but what is particularly important is the welder’s experience and their knowledge about stainless steel. We usually start by performing a test weld, where we check the welded joint and then correct certain parameters if necessary. It is performed at the beginning of a certain pipe parameter and is not repeated afterwards since the machine memorises the set parameters.

 

The welding process should be performed as follows; we clean the ends of the pipes, prepare the material, join the ends using coupling welds, and place them in the welding head. Choosing the right shielding (forming) gas is followed by the confirmation of welding. Once the tungsten electrode reaches 360 degrees, we conclude the process by finishing the welding, which is a demanding and also the most crucial part of the entire process.

MDM INOX S MDM METAL