Welded Threaded Pipe Fittings

Welded Threaded Pipe Fittings Key points of welding process

Preparation before welding

Material inspection:Confirm whether the materials and specifications of the pipe fittings and welding materials meet the design requirements,inspect the surface of the pipe fittings for defects such as cracks and sand holes,and check whether the welding materials are damp or deteriorated.

Cleaning:Thoroughly remove impurities such as rust,oil,moisture,and oxide scale from the welding area of the pipe fittings and its surrounding areas to ensure welding quality.

Groove processing:Process suitable grooves according to the thickness of the pipe fittings and welding requirements.Common groove forms include V-shaped,U-shaped,X-shaped,etc.,to ensure that the groove size and angle meet the standards.

Welding equipment debugging:Debugging welding equipment,setting welding current,voltage,welding speed and other parameters reasonably according to welding process,pipe material,thickness and other parameters.

Welding process control

Preheating(depending on the situation):For materials with poor weldability(such as high carbon steel,alloy steel,etc.)or thick pipe fittings,preheating is required before welding to reduce welding stress and avoid cracking.

Welding operation:Strictly follow the welding process,maintain appropriate welding speed,welding current,and arc length to ensure the depth,width,and forming quality of the weld seam.When welding multiple layers,attention should be paid to interlayer cleaning and temperature control.

Gas shielding(if applicable):When using gas shielding welding,the purity and flow rate of the shielding gas should be ensured to prevent defects such as weld oxidation and porosity.

Post weld treatment

Weld cleaning:After welding,use tools such as slag hammers and wire brushes to clean the surface of the weld from impurities such as welding slag and spatter.

Heat treatment(optional):For some pipe fittings that require high mechanical properties of the weld seam,post weld heat treatment may be necessary,such as annealing,normalizing,tempering,etc.,to eliminate welding residual stresses and improve the microstructure and properties of the weld seam and heat affected zone.

Quality inspection:Conduct visual inspection and non-destructive testing(such as ultrasonic testing,radiographic testing,etc.)on the weld seam to ensure that the weld quality meets the standard requirements.