Welded Threaded Pipe Fittings

Use Welded Threaded Pipe Fittings

Preparation before welding

Material cleaning:Thoroughly clean the welding parts of the pipe fittings and their surrounding areas of impurities such as rust,oil,moisture,and oxide scale.Mechanical cleaning can be carried out using tools such as sandpaper and wire brushes,and then wiped clean with organic solvents such as acetone.

Groove processing:According to the thickness of the pipe fittings and welding requirements,use appropriate methods to process grooves,such as V-shaped,U-shaped,X-shaped,etc.The size and angle of the groove should meet the requirements of the welding process to ensure the penetration and strength of the weld seam.

Selection of welding materials:Based on the material of the pipe fittings,choose welding materials that match them,such as welding rods,welding wires,etc.The quality of welding materials should comply with relevant standards,and they should be dried according to regulations before use.

Debugging of welding equipment:Debugging welding equipment to ensure its normal performance.Reasonably set welding current,voltage,welding speed and other parameters based on welding process,pipe material,thickness and other parameters.

Welding operation

Preheating(if necessary):For some materials with poor weldability or thick pipe fittings,preheating is required before welding to reduce welding stress and avoid cracking.The preheating temperature should be determined based on the material and thickness of the pipe fittings.

Welding process control:Strictly follow the welding process to maintain stable welding speed,welding current,and arc length,ensuring the depth,width,and forming quality of the weld seam.When welding multiple layers,attention should be paid to interlayer cleaning and temperature control to avoid defects such as porosity and slag inclusion.

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 impurities such as welding slag and splashes on the surface of the weld,making the surface of the weld flat and smooth.

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.

Installation and sealing

Threaded installation:When installing threaded fittings,pay attention to the tightening direction and torque of the threads to avoid being too tight or too loose.You can use a torque wrench to tighten according to the specified torque value to ensure a secure connection.

Sealing treatment:Use sealing materials correctly according to sealing requirements.When using PTFE sealing tape,it should be wound on the thread in the correct way,and the winding direction should be consistent with the tightening direction of the thread;When using sealant,apply it evenly to ensure the sealing effect.