Safety operation procedures for welders

1. During the operation, the construction personnel must wear all kinds of labor protection articles, such as work clothes, working caps, gloves, foot covers and other work clothes, which should not be tied in the waistband, but the foot covers should be tied in the trouser legs.

2. In the welding and cutting workplace, there must be fire prevention equipment, such as fire hydrants, fire extinguishers, sand boxes and buckets filled with water.

3. When welding operations are carried out in non-fixed places, a hot certificate must be obtained first, and a guardian and fire prevention measures are required before operation.

4. When working high above the ground, you should first apply for an aerial work permit, and the construction personnel should wear safety belts and abide by other relevant regulations on aerial work.

5, construction personnel in the construction process, should beware of electric shock, be careful not to be hurt by arc light and metal splash, to prevent explosion and other injuries.

6. After welding or cutting, carefully check around the welding site and confirm that there is no fire danger before leaving the site.

Extended data:

Basic operation of electric welding:

The welding operation is observed and carried out under the mask. Due to the unclear vision and poor working conditions, to ensure the welding quality, we should not only have more skilled operation technology, but also attach great importance to it.

Before welding, the surface within 20mm on both sides of the workpiece joint should be cleaned (such as derusting, degreasing, moisture removal, etc.), and the metal at the end of the covered electrode core should be exposed to facilitate short circuit arcing. There are two kinds of arc striking methods: arc striking method and arc striking method, among which arc striking method is easier to master and suitable for beginners to strike an arc.

1, arc striking

(1) scratch method. First, aim the covered electrode at the weldment, then gently cut the covered electrode on the surface of the weldment like a match, ignite the arc, and then quickly lift the covered electrode for 2 ~ 4 mm to make it burn stably.

(2) tapping method. Align the end of covered electrode with the weldment, then bend the wrist downward to make covered electrode slightly contact with the weldment, then quickly lift the covered electrode for 2 ~ 4 mm, and then lay the wrist flat after igniting the arc to keep the arc burning stably. This arc initiation method will not scratch the surface of the weldment and is not limited by the size and shape of the weldment surface, so it is the main arc initiation method used in the welding process. However, this arc striking method is not easy to master and needs to be improved.

2. Shipping

Rod conveying is the most important link in the welding process, which directly affects the shape and internal quality of weld. After arc striking, covered electrode has several basic actions on the normal operation surface: gradually feeding in the direction of molten pool, gradually moving in the welding direction, and swinging laterally.

(1) linear transportation method. When welding in this way, the covered electrode will not swing laterally, but move in a straight line along the welding direction. Commonly used for butt welding and multi-layer multi-pass welding of I-groove.

(2) Linear reciprocating rod feeding method. When welding in this way, the end of covered electrode swings back and forth along the longitudinal direction of the weld. It is characterized by fast welding speed, narrow weld seam and fast heat dissipation. Suitable for the first layer welding of multi-layer welding with large gap between thin plate and joint.

(3) Sawtooth transportation method. When welding by this method, the end of the coated electrode swings continuously, moves forward in zigzag, and stop for a minute at both sides. The purpose of swing is to control the flow of molten metal and obtain the necessary weld width, so as to obtain better weld formation. This method is widely used in production, mostly used for welding thick steel plates, butt joints of flat welding, overhead welding and vertical welding, and corner joints of vertical welding.

(4) Crescent transportation method. When welding in this way, the end of covered electrode swings from side to side in a crescent shape along the welding direction. Swing speed depends on weld position, joint form, weld width and welding current value. At the same time, it is necessary to stop at both sides of the joint for one minute to make the weld edge have enough penetration to prevent undercut. This method is characterized by good metal melting, long holding time, gas evolution and slag floating to the weld surface easily, high weld quality, but high weld residual height. The application scope of this method is basically the same as that of the zigzag method.

(5) Triangular transportation method. When welding in this way, the end of the coated covered electrode moves in a continuous triangle and moves forward continuously. According to the different swing forms, it can be divided into oblique triangle and regular triangle. The welding method is suitable for welding T-shaped welds and transverse welds with grooves at flat welding and overhead welding positions. Its advantage is that the molten metal can be controlled by the swing of covered electrode, which promotes the weld formation. The regular triangle strip transport method is only applicable to the vertical welding of butt joints and T-joints with grooves. Its characteristic is that it can weld a thick weld section at one time, and the weld is not easy to produce defects such as slag inclusion, which is conducive to improving production efficiency.

(6) Circular transportation method. When welding in this way, the end of the coated electrode moves continuously in a regular circle or an inclined circle and moves forward continuously. The straight ring strip method is suitable for welding the flat weld of thick weldments. Its advantages are that the molten pool exists for a long time and the metal temperature in the molten pool is high, which is beneficial to the precipitation of oxygen, nitrogen and other gases dissolved in the molten pool and the floating of slag. Oblique round bar conveying method is suitable for T-joints and transverse joints in horizontal and vertical positions. Its advantage is that it is beneficial to control the downward flow of molten metal under the influence of gravity and to weld formation.

3, weld repair

(1) loop ending method. When covered electrode moved to the end of the weld bead, he made a circular motion by wrist movement until the arc pit was filled, and then the arc was broken. This method is suitable for thick plate welding, and there is a danger of burning through when it is used for thin plate welding.

(2) Repeat arc extinguishing method. When covered electrode moves to the end of the weld bead, the arc goes out repeatedly and hits the arc pit several times until the arc pit is filled. This method is suitable for thin plate and high current welding, but it is not suitable for alkaline covered electrode, otherwise it will produce blowholes.

References:

Baidu encyclopedia-electric welding

Baidu encyclopedia-welding safety operation procedures