The welding process specification includes requirements for welders, welding equipment, and welding materials, pre welding preparation work, welding operation specifications, post welding treatment, and welder self inspection processes. Here is an example of argon arc welding.

1、 Requirements for welders, welding equipment, and welding materials

1. Argon arc welding welders must undergo professional department training and obtain a special welding operation certificate to work.

2. The argon arc welding equipment includes the power control system, gas path system, welding gun and other system parts. Check whether the equipment is intact and qualified before use.

3. The purity of argon gas must be ensured to be 99.99%, tungsten rods must have a factory certificate of conformity, welding wires must meet the corresponding chemical composition standards, and oil stains and rust should be removed before welding.

2、 Preparation work before welding:

1. Check if the drawings are complete, be familiar with the product process requirements, and check if the dimensions of the welded parts match the drawings;

2. Clean up burrs, oxide skin, rust, oil stains, and impurities within the scope of welding parts; Check for flammable and explosive materials within 10 meters of the welding site.

3. Check if the power cord, lead out wire, and wiring points of the welding machine are in good condition; The zero (ground) wire of the welding machine and the welding work return wire are not allowed to be connected to pipelines and machine equipment. The working circuit wire and the welding clamp handle should be well insulated, and the grounding of the machine casing must comply with safety regulations. All circuits should be independent or isolated.

3、 Operating procedures during welding

1. Selection of welding wire

For carbon steel materials such as 45, 50, and S50C, ordinary welding wire with 45 steel disc wire should be used.

1.2 Welding of 3Cr2Mo and 3Cr2NiMo [P20, 718 (M238, 738, 2738)] should be carried out using Ф 0.9~ Ф 718 special welding wire for 2

1.3 Welding of 4Cr13 (S136, GS083, 1.2083, 1.2316) should be carried out using Ф 0.9~ Ф S136 special welding wire for 2.

2. Welding adopts DC positive connection;

3. Inject air 5-10 seconds before starting the arc to remove air from the pipe.

4. Try to use short arc welding to enhance the protection effect, concentrate heat, and achieve uniform welding penetration.

5. If a short circuit occurs during welding, the welding must be stopped. If a defect is caused, the defect must be identified and replaced with a tungsten electrode before re welding.

6. After the welding is completed and the welding power is cut off, the gas must be continuously sent out for 3-5 seconds until the tungsten electrode and molten pool area are slightly cooled before the protective gas is stopped to avoid oxidation of the weld seam.

4、 Treatment after welding

1. Immediately remove slag after welding and clean it thoroughly.

2. Place the product in the designated position after welding.

5、 Self inspection requirements

Welders should perform self inspection against the drawings when welding various parts and after all assembly welding to ensure that the position and size of each part meet the requirements of the drawings. Parts with processing requirements should have sufficient margin on the processing surface, otherwise they need to be re welded. For areas with significant deformation, mechanical correction or flame heating correction should be used.