What is the reason why the current and voltage of submerged arc welding 630 are not adjustable? Wher

The current regulation of submerged arc welding is to adjust the current of the main welding machine through the head potentiometer, and the voltage is to adjust the motor voltage of the wire feeding mechanism, and the speed of wire feeding is reflected to the level of welding voltage.

Submerged arc welding. The trick of current and voltage.

1) Welding current.

The welding current is the main factor that determines the penetration of the weld. When other conditions remain unchanged, the welding current increases, the penetration depth h and residual height a of the weld increase, while the width of the weld does not change much. Under normal circumstances, there is a direct relationship between the welding current and the penetration depth

h= kmi km is the current coefficient, which is determined by the type of current, polarity, and diameter of the welding wire. Large welding current can improve productivity, but when the welding current is too large, the width of the welding heat affected zone increases, and it is easy to produce overheating structure, so that the toughness of the joint is reduced. In addition, excessive current can easily lead to undercuts.

Defects such as welds or burn-throughs. If the welding current is too small, it is easy to produce defects such as non-fusion, non-penetration, and slag inclusion, which will make the weld deformed and deteriorate.

2) Current type and polarity.

When DC reverse connection is used, the deposition speed is slightly lower and the penetration depth is larger. In general, DC reverse connection is used for welding. When DC forward connection is used, the deposition speed is 30% to 50% higher than that of reverse connection, but the penetration depth is shallow, which reduces the percentage of base metal in the deposited metal.

It is especially suitable for hardfacing welding. When the hot crack tendency of the base metal is large, in order to prevent hot cracking, DC positive connection can also be used. When using AC for welding, the penetration depth is between DC forward connection and DC reverse connection.

3) Arc voltage.

With the increase of arc voltage, the melting width increases, while the penetration depth and residual height decrease slightly. In order to ensure the stable combustion of the arc and the appropriate welding seam forming coefficient, the arc voltage should maintain an appropriate relationship with the welding current. When the welding current increases, the arc voltage should be increased, and the range of welding voltage corresponding to each welding current should not exceed 10V.

When the arc voltage is taken to the lower limit, the weld bead is narrow; When taking the upper limit, the weld bead is wide. If the arc voltage is outside this suitable range, the weld formation will deteriorate.

In addition to having an impact on weld forming, the arc voltage also changes the chemical composition of the deposited metal. When the arc voltage increases, the amount of flux melts increases, slag and liquid metal.

As the ratio between weights increases, the alloying elements in the transition to the deposited metal increase.

How to adjust the current and voltage of submerged arc welding? Hello dear, submerged arc welding is basically about 10 current plate thickness, the voltage is adjusted according to the width of the weld according to the need, and the speed is related to the molding, and the gear is slowly adjusted. 4mm plate thickness double-sided suspension welding does not leave gaps, front current 120 to 150, voltage 24-28, reverse side 150-180, voltage 26-30.

The welding speed comes according to molding. If it is single-sided welding and double-sided molding, it is recommended to have a gap, add a ceramic liner on the back, do not open the groove, the current is 380-400, and the voltage is 28 to 30. I hope it can help you.