Technology

SAW- Submerged Arc Welding Process

Submerged welding The principle of operation is by feeding the electrode into the workpiece at a specified speed. and the feeder platform moves along the weld line. This can be automatic or manual control. During welding, flux is introduced into the area around the electrode to cover the welding area. During this period, the heat from the arc melts some of the flux into the electrode tip. and the surface of the workpiece is formed into a melting point of metal This will cause air bubbles to escape from the smelting pond. Area above the weld covered with flux will be prevented from contamination of the atmosphere entering the smelting pond The flux also helps dissolve impurities in the workpiece metal and electrode. to float on the top surface of the weld. In addition, the flux The additions may help to fill or remove some metals. and when the weld is cooled The surface flux hardens to cover another layer of weld. which is required to eliminate the flux that the surface is removed before the next round of welding.

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how to use

Under-flux welding or submerged welding Able to use for welding in 3 types: semi-automatic, automatic, and machine as follows.

    – Semi-automatic welding In this method, the electrode is fed using a wire feeder and the flux is fed from a flux bag (Hopper) by gravity into the flux nozzle. Small electrode and medium welding speed. And to control the movement, it can be done manually or driven by a motor.

    – automatic welding will be welded using a machine which does not require any assistance to adjust

    – welding by machine will be like an automatic But needs someone to control the welding position, open, close, adjust the welding speed.

equipment

equipment used for Under-flux welding or submerged welding There are five main components:

    Power Supply

    Electrode feeding system

    Flux supply system

    Motion control system

    process control system

There may also be other additional equipment such as a flux suction system. recycle or position control system

There are several types of power supply systems:

  1. DC system

1.1. DC Constant Voltage (CV) is suitable for semi-automatic welding with current range of 300 – 600 A and electrode size 1.6 , 2.0 and 2.4 mm. Automatic is used in the range of 300 – 1000 A and electrodes of 2.4-6.4 mm. However, they should not be used above 1000 A due to severe arc blow (see article Welding – SMAW). CV is commonly used for welding thin metals and requiring high speeds.

1.2. DC Constant Current (CC) is used with a current not exceeding 1500 A. This system must have a voltage regulator to control the electrode feeding speed while the arc voltage is changed. to help keep the arc length constant But because this type of control system is expensive, electrode feed rate control is preferred. Fixed speed model with CV instead.

1.3. CV /CC This system can be adapted to both CV and CC types. It can be used at a maximum current of 1,500 A, but is generally used at a current less than 650 A.

  1. AC system

This system is commonly used in the current range of 800 – 1,500 A and uses a wide range of electrodes, low electrode-to-workpiece spacing and low ARC blow.

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