In order to achieve the best quality of welded tube and highest efficiency, we advise induction welding only for samll tube (86mm maximum usually less than 200kw or 25okw solid state welder), and both induction welding and contact welding for larger pipe (114 mm or above, usually 300kw and above solid state welder.)

Except for welding steel tube, EECTECH has developed welder for aluminum & brass tube welding.

In order to get a quality welded joint, apart from selecting the proper power and frequency, other factors are involved such as:
● Proper pipe forming and ensuring that the edges face each other properly.
● The right position of the inductor
● A properly placed impeder, well-cooled and made of the right material.
● A constant thickness of the steel sheet.
● Steel quality appropriate for welding.
● Good surface condition of the sheet to be welded.

The types of steel that can be welded best are the ones that contain under 0.3% carbon. (Steels with a greater carbon content can be welded, but with less efficiency and a danger of self-hardening in the welded area. With pickling or galvanised steels better efficiencies are obtained than with non-pickled steels.

What is the application requirements of our HF induction equipments?

1.      Indoor installation with good equipment grounding. There should be a clear distinction between the color of earth wire and control wire. The earth wire sectional area > 4mm2 and earth resistor is no more than 4 Ω;
2.      The altitude should be no more than 1000 meters, otherwise the rating should be lowered during operation;
3.      The ambient temperature should be between -10 °C and +40℃;
4.      Air relative humidity should be lower than 85%;
5.      No heavy vibration, no dust conductive, no corrosive and explosive gas allowed;
6.      Installation inclination should be ≤ 5 degrees;
7.      Installation occasions should be well-ventilated.

1.  Zero wire (N)
Equipment adopts 3-phase 4 wire system, of which zero wire (N) should use not less than 2.5mm 2 copper conducting wire and connect with “N” in terminal row to meet the requirements of power source single phase 220V.
     Note: zero wire should be connected to grounding wire separately.
2.  Grounding wire（ ）
This equipment adopts separate earth connection system for the consideration of equipment normal operation and security. The system is composed of grounding body and grounding wire, and the total loop resistance should be less than 4Ω.
     Note: the grounding system is an independent system which should be avoided to be shared with and should be far away from large power machine lines, and keep checking and maintenance regularly.
    2.1 Requirements for grounding body
① Galvanized angle steel（45×45mm）with length of 2.5m and quantity of more than 3 pieces.
② Embeded vertically as horizontal or triangle.
③ Space interval for angle steel: 2.5m～3m.
④ Building-in depth≥ 0.6m.
⑤ Connect to grounding body vertically:
   Weld with galvanized flat steel together.
   If the grounding body lead-out wire and grounding net are connected by screw, it should be tight and    make anticorrosive treatment for the joints.
⑥ In order to add conductivity of the grounding body, the soil can be made resistance reducing treatment poured with lime, salt, water and carbonic acid liquid proportionally.
   2.2 Grounding wire.
Galvanized round steel of more than Ф8 should be used for grounding wire connection, and the connection to grounding body should adopt lapping mode. The A3 steel lug is welded on galvanized round steel and fixed on the ground bolt, which is designed on the lower part of the back side of the equipment.

The diameters of the pipes made with this system range from 10 to 280 mm, with thicknesses going from 0.5 to 16 mm. The most customary range lies between 15 and 165 mm in diameter and from 0.8 to 8 mm thick. The production speeds of these lines go up to 150 m/min although in general these are from 60 to 120m per min.

The raw material for making welded pipe is a steel strip coils. A roller carrier forms the pipe, which then goes inside an inductor connected to a welder (generator) where the edges of the pipe are heated up to melting temperature. Then rollers apply the pressure required for the edges to join, thus welding the pipe.