Exothermic Welding Molds – High Thermal Conductive Welding Tools

  • High thermal conductivity and high temperature resistance.
  • Low coefficient of thermal expansion and high heat resistance.
  • High strength, corrosion resistance and self-lubrication.
  • Very little or no reaction with most molten metals.
A well-assembled exothermic welding mold with an open cover

Graphite material is widely used in the production of exothermic welding molds due to its excellent thermal conductivity, high temperature resistance, high melting point, and low reactivity with molten metals.

During the exothermic welding process, a chemical reaction occurs between the welding powder and the metal to be welded, generating a large amount of heat. Graphite has an extremely high thermal conductivity and can transfer heat quickly, making the mold heat up quickly and melt the welding powder and the metal to be welded. The melted metal then fills the mold cavity and solidifies to form a strong joint. As the graphite material has a low coefficient of thermal expansion, it will not significantly expand or contract when exposed to high temperatures, which helps to maintain its shape and size during the welding process.

In addition, graphite material is easy to process and can be made into exothermic welding molds of various shapes and sizes through machining.

Table 1: Specifications of Exothermic Welding Molds
Model Density (g/cm3) Particle Size (μm) Specific Resistance (μΩ.m) Porosity Shore Hardness Compressive Strength (MPa) Flexural Strength (MPa) CTE (× 10-6°C-1) Application
IS-2(Isostatic) 1.76 20 15 20% 60 95 50 5.9 Heat exchanger/all kinds of machining
IS-3(Isostatic) 1.85 10 12 13% 48 85 46 4.3 Sintering/all kinds of machining
IS-4(Isostatic) 1.90 5 12 13% 48 85 46 4.3 Sintering/all kinds of machining
MD-1(Molded) 1.78 25 12 20% 48 80 40 5 Sintering/all kinds of machining
MD-2(Molded) 1.72 25 12 19% 45 60 32 5 Sintering/all kinds of machining
MD-3(Molded) 1.56 25 12 23% 35 38 16 5 Sintering/all kinds of machining
  • 1 MPa = 10.2 kgf/cm2; 1 W/m.k = 0.86 kcal/cm.h.°C
  • These properties are typical values and not guaranteed.
Process Introduction: Mold Structure & Welding Forms

The exothermic welding mold is mainly composed of a crucible for holding welding metal powder, an iron outlet for the flow of molten metal, and a welding cavity for placing the metal plates to be welded.

Exothermic welding graphite molds can be used for welding various metal materials including pure copper, brass, bronze, copper-clad steel, pure iron, stainless steel, forged iron, galvanized steel, cast iron, copper alloys, and alloy steel.

8 Exothermic Welding Forms

These welding forms include cable to cable welding, cable to metal bar (strip) welding, cable to ground rod (pole) welding, cable to metal plate welding, metal bar (strip) to metal bar (strip) welding, metal bar (strip) to ground rod (pole) welding, metal bar (strip) to metal plate welding, and metal rod to metal plate welding.

Every welding form contains different connection methods. For example, cable to cable welding includes butt connection, cross connection, parallel connection, t-joint connection, etc. Every form can perform well welding.

The detailed structure diagram of exothermic welding mold