1) exothermic welding method will produce high temperatures, inevitably metal particles escape, and cause harm to the construction personnel's body. In the use of exothermic welding process, on the one hand, should be used in low-smoke formula, from the root to reduce
less metal particles escaping; on the other hand, should strengthen the protection of construction workers, strengthen ventilation, wear a good mouth
mask, to prevent metal poisoning of construction workers.
2) construction operation, the site within 1.50 meters, there shall be no unrelated personnel stay.
3) The operator must wear work gloves with certain heat insulation effect.
4) The operator must not face the opening of the mold to operate the construction.
5) The operator must leave the mold at least 1.50 meters as soon as the ignition powder ignites during ignition.
6) When the welding is finished, no one shall immediately come into direct contact with the mold.
7) When the welding is finished, the mold and the welded wire must be allowed to cool down for 30 seconds before removing the wire with an iron pliers
8) Insulation of the welded wire must be carried out only after the wire has cooled down completely.
Exothermic welding introduction: a. Product performance and characteristics: heat fusion welding (exothermic welding) is the use of exothermic flux chemical reaction as a heat source, generating high temperatures and through the molten mold to achieve the purpose of welding welding welding, which does not require external energy, is the best way to weld metal conductors. Can be copper and copper, copper and steel and other identical or different metals are completely fused between the molecules of the real bonding, and thus make the lightning protection grounding devices become permanent maintenance-free devices.
Exothermic welding is a simple, high-efficiency, high-quality metal connection process. Mainly used for railroads, highways, power plants, substations, switching stations, high-voltage transmission lines, electrified railroads, telecommunications, mobile communication base stations, microwave relay stations, ground satellite receiving stations, radar stations and other key projects, as well as valuable precision instruments, computer equipment, post and telecommunications program-controlled equipment, broadcasting and television equipment, electronic and medical equipment, such as grounding and protective grounding; petroleum pipelines and oil and gas tanks. Flammable and explosive substances warehouse lightning grounding.
1. process principle
(1) exothermic welding is through the chemical reaction between aluminum and copper oxide (exothermic reaction) to produce liquid high-temperature copper and aluminum oxide residue, and the use of exothermic reaction of the high temperature to achieve high-performance electrical fusion of the modern welding process. Exothermic welding is suitable for copper, copper and iron and iron alloys, such as the same or dissimilar materials between the electrical connection, it does not require any additional energy or power.
(2) Reaction formula:
3Cu2O+Al┄┄>6Cu+Al2O3+heat (the temperature can be up to 2537 ℃ or more)
2, the process
The welded object laying ---- select the mold ----- weld preparation ----- weld in place ------- placing a steel plate ------ --- Add the reaction powder ------ Igniter ignition ----- Welding ------- Cleaning the mold
3, the main points of the operation
(1) The welded material is laid in place according to the design requirements, in the need to weld the part of the exothermic welding.
(2) select the mold touch folder and tools
1) mold
mold made of graphite, is a graphite crucible (see below), due to the graphite is more fragile, can not withstand the throwing and strong impact, so do not exceed the size shown on the nameplate of the mold Bureau of the fusion of the material forcibly placed into the mold made of graphite is more fragile, can not withstand the throwing and strong impact, so do not will not exceed the size shown on the nameplate of the die Bureau of the fusion of material into the mold made of graphite is more fragile, can not withstand the throwing and strong impact. The fused material exceeding the size shown on the nameplate of the mold bureau should not be forced into the mold, or metal substances, hard tools, etc. should not be used to remove the residue.
4, several different grounding body exothermic welding preparation
1) cable (wire) welding preparations and essentials
① To get a perfect welded joint, the welded cable must be kept clean and dry.
② Oil-filled cable must be removed from the cable line on the grease dirt, you can use degreaser, gasoline, carbon tetraoxide and other cleaning. If necessary, you can use molten tin water.
③ surface oxidation of the cable can be cleaned using a copper wire brush.
④ water-containing cable should be dried with a blowtorch and then use a steel brush to remove the oxidized layer, water-containing oil-containing cable, such as direct welding will make the reaction of the copper liquid spray out of the mold, it is very dangerous, need special attention.
5 open cable head will make the mold can not close, resulting in a large gap, causing copper leakage. Therefore, when cutting cable wires, care should be taken to ensure that the cut is flat, and copper wire or stranded cloth can be used to fix the cut before cutting.
6 If in the welding cable with tension, you can use the cable fixed clamping taut.
2) grounding rod welding preparations and essentials
① grounding rod is malleting the end will be deformed, must be removed or smoothed before being put into the mold, otherwise it will cause the mold closure is not tight, resulting in copper leakage. You can also use the steel set to protect the end before malleting.
②Earth rod with screw holes or bindings at the end need to remove the end before welding.
③ grounding rod connection needs to be kept clean, such as rust, oxidized skin, etc. must be cleaned with a steel brush or sandpaper before welding, otherwise there will be a porous welded joints.
④When welding the diameter of the rod is smaller than the mold hole, can be used to make up for the steel tape wrapped grounding rod connector.
3) Copper plate, steel plate and cast (pig) iron surface welding preparations and essentials
① Clean the connection surface before welding, remove the surface of water, oil, stains and so on.
② on the surface of the adherents should be cleaned with grinding wheels, coarse files and other tools.
③ Galvanized steel welding point surface needs to remove the coating before welding.
4) line nose, busbar (bus), busbar (tube bus) welding preparations and essentials
① Clean the connection surface, remove attached moisture and grease.
② The internal and external surfaces of the welded parts of the busbar need to be cleaned before welding.
③ Steel brush, sandpaper, coarse file and blowtorch can be used.
5) rail welding preparations and essentials
① rail welding part of the surface corrosion needs to be completely removed, can use special grinding wheel grinding.
② If the rails with grease and moisture need to be removed first, and then rust.
③ If the rail surface has a convex mark needs to be smoothed.
6) steel welding preparations and essentials
① Remove the rust on the surface of the steel, polished.
② Remove the steel surface grease, water.
③ Use steel brush, sandpaper, coarse mesh file and blowtorch.
Advantages of exothermic welding: 1, the current-carrying capacity of the fusion point (melting point) and the same conductor, with good electrical conductivity, tested, welded before and after the DC resistance ratio change rate close to zero. This is any kind of traditional connection can not be compared.
2, the welding point is a molecular bond, permanent, not aging.
3, the welding point like copper is not affected by corrosion. 4, will not be subject to high surge current damage. Tests show that in a short period of high current impact, the conductor melts before the fusion welding joints.
5, easy to operate, simple. No need for specialized personnel.
6, the equipment is simple, lightweight, easy to carry, easy to operate.
Melting mold, auxiliary tools 1, melting mold: exothermic welding mold made of graphite material, fine workmanship, unique design, to ensure high performance and high life. The design of the mold ensures that the molten flux can flow freely in the cavity, and it is easy to separate the mold from the welded joints, making the life of the mold increased. Heat welding molds can be welded more than 50 times on average, and can be used more than 100 times if the joints are simple and carefully handled. We can equip various types of easy-to-operate mold clamps according to the needs of customers and on-site welding. Mold clamps used to open and close the mold, the company has a special production and mold corresponding to the mold clamps. 2., auxiliary tools: exothermic welding operation process, there are the following auxiliary tools: blowtorch: used to dehumidification of the mold, preheating, in order to enhance the quality of welding; mold clamps: after the mold alignment is good, the mold clamps to clamp, fix the mold, in order to weld the smooth progress; horse bow: play a role in assisting the fixation; high-temperature gloves: to prevent the hand scalded; ignition gun: ignition of the soldering powder; copper brushes: to remove the impurities of the mold cavity; brushes: to the weld Good welding point brush anticorrosion special treatment; fire clay: when the mold wear or gap is too large, the available fire clay sealing; tool box: used to load the tools used for welding, easy to manage the storage of tools; screwdriver: the operation of the role of auxiliary.
Four, commonly used product specifications
Name Model Specifications
Hot melt flux LSDHJ 65# 90# 115#
150# 200# 250#
Hot melt molds LSD-MJ 1# (≤ 90# flux) 2# (90# flux ≥ ≤ 200# solvent) 3# (200# flux ≥ ≤ 300# solvent)
Hot melt moulds LSD-MJ 1# (≤ 90# flux) 2# (90# flux ≥ ≤ 200# solvent) 3# (200# flux ≥ ≤ 300# solvent) This is the first time to use the hot melt molds. 300# solvent)Application 1. Lightning grounding and surge protection.
2. Electrical equipment grounding engineering treatment.
3. Petrochemical engineering construction.
4. Railway, highway, airport construction.
5. Intelligent building construction.
6. Cathodic anti-corrosion protection.