Introduction of mold exothermic welding

Mold exothermic welding is made of high-purity graphite and is used for the forming of welding heads for grounded exothermic welding. A complete mold consists of a mold body, top cover, and hinge.

The main performance of mold exothermic welding

Fine workmanship, unique design, excellent performance, long use time; simple operation, no external power supply and heat source, low welding cost, stable and reliable quality.

The scope of use of mold exothermic welding

Mold exothermic welding is mainly used for the welding of metal materials in lightning protection and grounding projects and is suitable for various industries. It is more suitable for the welding of field cables and other metal components, and can also be used for the connection between copper core cables and steel structure welding or copper core cables during the installation of cathodic protection systems.

Other Accessories

Other accessories are also required during the use of exothermic welding molds. The required accessories include: mold clamps, C-type pliers, caulking glue, igniters, steel brushes, brushes, mold cleaning shovels, etc. The above is the introduction of mold exothermic welding from Sichuan Sunlight intelligent electric equipment Co., Ltd.

mold exothermic welding

Process of mold exothermic welding

In order to achieve the highest service life of the mold, the use of flux-cored wire surface surfacing technology can obtain a thicker surface layer and a stable surface structure, and it is easier to form a surface layer that is wear-resistant and thermal-fatigue. , save materials and reduce processing costs.

Die surfacing flux-cored wire

The CO2 self-shielded flux-cored wire used is rolled on a flux-cored wire forming machine. Die welding wire, niobium carbide welding wire, there is no crack after welding, and the surfacing layer is smooth and beautiful. Excellent base metal bonding performance, good toughness, and will not fall off. The above is the process of mold exothermic welding.

mold exothermic welding

Precautions for mold exothermic welding

Welding parameters

Beijing Guben KB968 die welding wire diameter is 1.6mm, welding current is 220-280A, welding voltage is 22-28V, the protective gas is pure carbon dioxide or pure argon gas, the protective gas volume is 20L/min, and the wire extension length is 15-20mm, The welding speed is 35cm/min, the angle of the welding torch is 80 degrees, and the current type is DC reverse connection.

Die Welding Process

Strictly implementing the correct surfacing process is the decisive factor to ensure the quality and success of surfacing. The surfacing process includes the following steps

Preparation before welding

Before surfacing welding, use the mechanical processing method to rough process the surfacing hole pattern to remove the fatigue layer and defects on the surface of the substrate, especially the cracks that must be completely removed. Flaw detection, check the internal conditions and weld only after confirming that there are no cracks.

warm-up

In order to prevent the occurrence of cracks, it must be preheated before surfacing, and the preheating temperature is determined by the composition of the base and surfacing materials. In order to obtain uniform hardness on the surface, the preheating temperature should be above the Ms point of the material. In order to reduce thermal stress, the heating rate should also be controlled. The heating rate is about 20°C/h at the beginning of 100°C and can be 40°C/h after that. Even heating is required.

welding

Mold exothermic welding is the key to the success or failure of surfacing welding. To obtain an ideal surfacing layer, certain variable factors must be comprehensively considered, such as welding voltage, welding speed, welding current, and welding materials.

post-weld treatment

In order to reduce cracks caused by volume stress caused by different cooling rates on the surface and inside, mold exothermic welding needs to control the cooling rate. In order to eliminate the welding residual stress, reheating treatment must be carried out. The reheating temperature depends on the operating conditions of the hot forging die, and is generally controlled between 450-600°C. The reheating temperature is high, and the internal stress is completely eliminated, but the hardness is reduced. Therefore, the choice of the reheating temperature should not only ensure a certain hardness of the surface of the hot forging die but also try to eliminate the internal stress. The heat recovery time is usually 3~10 hours.

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