Technology

Level of electric current in Submerged Arc Welding

The nature and size as well as the uniform distribution of the flux are important for feed and recovery, the degree of current applied, the shape and consistency of the weld. Usually, an increase in welding current is used as the flux is smaller and the percentage of smaller particles increases. The manufacturer specifies the size of the flux with two numbers, where the first part indicates the mesh size (mesh) through which the desired particles can pass. The second is the size of the mesh that most particles cannot pass through.

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In practice, there are many variables that affect welding as follows:

– current used

Will affect the melting rate of the electrode, the depth of the weld and the melting of the workpiece. If the current increases, it tends to increase the variables, but if the current is too high, it consumes the electrode. The electrodes and welds are too large and may warp more in the workpiece and may undercut (see the article Electrical Welding – SMAW). and an uneven arc occurs

 – welding pressure

The voltage adjustment is adjusted according to the arc length between the electrode and the workpiece. If the voltage increases, the arc length is greater. On the other hand, if the voltage is reduced, the arc length decreases. The voltage value does not affect the electrode consumption as much as the current. But the pressure value will affect the shape of the weld and the cross-sectional area of ​​the weld more. If the welding pressure is increased while the current and welding speed are constant, it will

     – Welds are flat and wider.

     – Consume more flux

     – The porosity of the weld is reduced.

     – Decreased strength

     – More Alloy is pulled out of the flux.

    – If the arc voltage is too high, it will cause

    – Welds are wide and cracks occur.

    – Difficult to remove slag from weld

    – Arc weld shape where cracking may occur

    – Undercut occurs at the edge of the weld

    Lower pressure increases penetration depth and reduces arc blow, but if the pressure is too low it will narrow the weld and make it difficult to remove slag.

welding speed

If the welding speed increases, it will

      – The heat used to connect one unit, the length of the weld is reduced.

      – The amount of metal added to the weld, the unit length of the weld is reduced, thereby reducing the strength, thereby making the weld smaller.

The welding speed will have a greater effect on the penetration depth than the current used. If the speed is too high, it will cause Undercut, Arc blow, and weld joints are more porous.

If the speed is too low, it will cause

     – Welds will bend, which will cause cracking.

     – The arc is too intense.

     – Slag will melt into the weld and the weld will look rough

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