Adjustment of Welding Process Parameters in High Frequency Welding

There are many factors affecting the high-frequency welding process: extrusion roller, welding pipe, welding speed, welding power and frequency, welding form, impedance, V angle of welding area, etc.

1.Extrusion roller and guide before coil feeding

The position of the horizontal height of the extrusion roll directly affects the butt joint of the last steel strip edge, and the guiding position of the extrusion roll directly affects the V angle, which can directly affect the welding process parameters.

2.Extrusion roll after coil out

Extrusion roll diameter is an important parameter affecting product commissioning. In principle, the smaller the extrusion roll diameter, the larger the range can be provided for welding process adjustment.

3.Mechanical property parameters of materials

The mechanical performance characteristic parameters of the base metal, such as material hardness, strength, elastic modulus, etc. These performance parameters have different adjustment requirements for the design of extrusion roller passes, roll material requirements, forming requirements, edge matching requirements into the center of the extrusion roller, and materials with different extrusion forces. The welding profile adjustment personnel need to make different adjustments according to the material characteristics.

4.Electrical, magnetic and thermal characteristic parameters of materials

The electrical characteristic parameters of the base metal need to be considered: the resistivity, permeability, thermal diffusion coefficient and melting point of the material. According to the melting point and resistivity of the material, it can be roughly determined that different materials have requirements for the resonant current of high-frequency power supply required for welding, while the current of induction welding is eddy current with skin effect, and the generation of eddy current is closely related to the permeability of the material, The permeability of different materials determines the need to select the appropriate high-frequency power frequency to match it in order to achieve the best welding current demand.

5.Influence of welding power on welding process

In the process of high-frequency welding, how much welding power is appropriate? In fact, under a certain welding speed of products of corresponding specifications, different unit forming conditions or different operators are not necessarily the same, because there are many subjective and human factors, but no matter what, the following judgment conditions can be used as the requirements for welding power:

a.The welding power needs to make the weld meet the melting conditions required by the extrusion of the unit;

b.The weld flare test does not show strip cold welding cracks (insufficient welding power);

c.The weld width shall be free from obvious over width and over burning (excessive welding power);

d.Proper amount of spark in welding extrusion center;

6.Influence of welding frequency on welding process

The welding frequency in high frequency welding, especially in induction welding, mainly affects the following aspects in the welding process:

a.Width of heat affected zone of weld;

b.Electrothermal penetration depth of weld heating part;

c.Equivalent load resistance of welding area in coil;

When the welding frequency parameter is applied to products with extreme wall thickness, such as thick wall pipe (wall thickness greater than 10mm) or thin wall pipe (wall thickness less than 1mm), its impact on the welding process quality is obvious. In addition, when high-frequency welding is carried out for raw materials with low permeability, it is also key to select the frequency.