Ductile Iron Pipe Manufacturers Introduce Welding Temperature Control Techniques in Pipes
Ductile Iron Pipe Manufacturers Introduce Welding Temperature Control Techniques in Pipes Thread Rod,Threaded Bar,Galvanized Threaded Rod,1 Inch Threaded Rod Hebei W.M fastener manufacturing CO.,Ltd , https://www.wmfasteners.com
Ductile cast iron pipe manufacturers put the steel strip into the welded pipe unit and rolled it through multiple rollers. The strip is gradually rolled up to form a round billet with an open gap. The amount of pressurization of the squeezing roller is adjusted to make the weld gap. Control in 1 ~ 3mm, and make the weld ends flush. If the gap is too large, then the proximity effect is reduced, the eddy current heat is insufficient, and the weld intergranular junction is poor and unfused or cracked. If the gap is too small, the proximity effect will increase, the welding heat will be too large and the welding seam will be burned; or the weld will form a deep pit after being squeezed and rolled to affect the surface quality of the weld.
The welding temperature is mainly affected by the high frequency eddy current heat power. According to formula (2), the ductile iron pipe manufacturer knows that the high frequency eddy current heat power is mainly affected by the current frequency, and the eddy current heat power is proportional to the square of the current excitation frequency; and the current The excitation frequency is also affected by the excitation voltage, current, and capacitance and inductance. The excitation frequency formula is:
f=1/[2Ï€(CL)1/2]...(1)
Where: f-excitation frequency (Hz); capacitance in the C-excitation circuit (F), capacitance = charge/voltage; inductance in the L-excitation circuit, inductance = magnetic flux/current. Visible to the excitation frequency and excitation circuit The square root of the capacitors and inductors is inversely proportional to the square root of the voltage and current. If the capacitance, inductance, voltage, and current in the loop are changed, the magnitude of the excitation frequency can be changed to achieve the purpose of controlling the welding temperature. For low carbon steel, the welding temperature is controlled at 1250~1460°C, which can meet the requirements of 3~5mm penetration of pipe wall thickness. In addition, the welding temperature can also be achieved by adjusting the welding speed.
Ductile iron pipe manufacturer introduction: When the input heat is insufficient, the edge of the heated weld can not reach the welding temperature, the metal structure remains solid, forming no fusion or incomplete penetration; when the input heat is insufficient, the heated welding The edge of the seam exceeds the welding temperature, resulting in overheating or droplets, which cause the weld to form a hole.
Above source information of ductile iron pipe welding temperature control method