1. Preparation before welding
Welding equipment: Domestic welding machines can be used for this welding work; Dingding automated welding equipment is used for filling and covering.
Welding materials: Choose welding wire for root welding base material, such as 304 or 316 stainless steel wire spool.
Bevel cleaning: Before assembly, bevel cleaning should be carried out first. Use an angle grinder or electric wire brush to remove oil, rust, water and other dirt within 25mm of the bevel and the edges of the front and back until all metallic luster is exposed.
Nozzle pairing: The nozzle pairing directly affects the quality of root welding. It must be carried out strictly according to the welding process parameters, and the blunt edge of the groove is controlled within the range of 0.5~2.0mm; because the entire welding process is automated welding, the groove gap does not need to be Keep. The picture below shows manual welding, leaving a gap of 2.5~3mm.
2. Welding
01 Select welding process parameters Welding process parameters are an important basis for guiding welding operations. From root welding to filling and cover welding, welding process regulations must be followed and welding process parameters must be strictly controlled.
02 Root welding Preheating before welding: X70 steel grade is higher and has a strong tendency to crack. It must be preheated before root welding. The groove and surroundings must be heated to 80~120℃ before root welding can be carried out.
Root welding: also known as bottom welding, generally self-melting base material does not require filling wire. Usually high-temperature and high-pressure pipeline welding must pass a first-level or second-level flaw detection test, which requires argon gas protection inside the weld bead in order to achieve single-sided welding and double-sided forming. This requires sufficient experience to face various materials. , size of pipe fittings to call up the corresponding base welding parameters. The equipment has corresponding experience data, can randomly store up to one hundred sets of welding processes, and can realize one-click operation for welding.
03Filling welding
X70 grade steel has a certain tendency to crack. To prevent cracks, the interlayer temperature must be above 80°C. Appropriate heating measures must be taken during welding construction in winter.
04 cover
Cover welding should ensure that the appearance and size of the weld are qualified, there are no welding defects, and the shape is beautiful. It is the last process of the welding joint and it is also a key process.
