1. General safety procedures

(1) proper personal protection. Welding operation according to the labor protection provisions must wear protective clothing, insulated boots and gloves, and keep dry and clean.

(2) welding work, should first check whether the safe and reliable equipment and tools. Safety checks have not been allowed to start operation.

(3)Welding Electrodes is replaced when you have to wear welding gloves, not bare hands operation. In the charged case, do not move away welding clamp weldment in the armpit or the cable hanging in the neck wound.

(4) in exceptional circumstances (such as body sweating in summer, wet clothes), do not rely on a live table, weldment or contact welding pliers, etc., to prevent accidents. Welding operations in wet locations; on the ground should be covered with rubber sheet or other insulating material.

(5) welder sliding knife, to sideways toward the gates, to prevent the arc spark burns the face.

(6) the following shall be cut off only after the power switch: to change the welding joints; replace the need to divert the second weldment line; mobile workplace; repair welding machine failure and replacement fuse.

(7) welding machine installation, repair and inspection by the electrician, the welder will be allowed to overhaul.

(8) prior to welding, job site should be within 10m of inflammable and explosive materials removed or disposed of properly to prevent fire or explosion.

(9) to leave the job site when work is completed to be cut off the power to clean up the scene to prevent accidents left.

(10) when using the line lighting, the voltage should not exceed 36V.

2. Equipment safety checks

(1) the necessity of equipment safety checks

Welding work, should first check the welding machine and tools are safe and reliable, which is to prevent electric shock and other equipment very important part of the accident.

(2) welding arc welding equipment check before the items.

1) Check the power of the first and second winding insulation and the ground situation. Should check the reliability of insulation, wiring is correct, the nameplate voltage and power match.

2) Check the reliability of power supply ground.

3) Check the noise and vibration.

4) Check the welding current adjustment device reliability.

5) Check whether there is insulation around the damage.

6) Check for short circuit Aluminum Electrode clamp is placed on the pieces to be welders.

Under the composite primer to Welding Electrode is welding and thermal welding under the welding method used, filling and cover pass welding welding method using the welding process up. Its mainly used in welding the pipe wall thickness greater.

Period of the 1990s is not large pipe wall thickness is widely used in domestic and international oil, gas and water industry in the long-distance pipelines, water pipelines in the general industrial pressure up to more than 1m diameter, wall thickness of 10 ~ 60mm, in northern China cold regions oil and gas pipeline wall thickness of 10 ~ 24mm. Compared with traditional welding up, because next to the welding heat input is low, shallow penetration, thinner weld, pipe wall thickness increases with the number of layers is also increasing rapidly weld, welding time and labor intensity will be increased , next to the weld is difficult to simply play the welding speed, high efficiency characteristics. Manual arc welding of steel pipe wall thickness at different levels and number of channels shown in Table 2. The backing welding, heat welding used to weld the next, filling and cover pass welding using welding up next to the welding of complex technologies can play the advantages of two kinds of welding methods to achieve high quality and efficient results. In the semi-automatic gas shielded welding technology is not applied to the next pipeline construction before the big wall pipe to use more complex next to the welding technology. Industrial Park as a water pipe used in pipeline project specifications φ400mm × 14mm, material is Q235-A. Weld backing during welding, Aluminum Electrode with cellulose electrodes J425G, filling and cover pass welding using ordinary J422 (E4303) electrode, the weld bead layer welded by a single bit to the required level reduced to 7-8 4 to 5 layers, welding time can be shortened 30min, greatly improving production efficiency.