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S. Sahu et al.
5.3 Influencing Factors for Dissimilar Welding
The development of various alloys has served many applications but welding them
together perfectly and repeatedly continues to be a difficult process. The factors
influencing a dissimilar joint have been discussed below:
5.3.1 Solubility
The most fundamental enabler of a dissimilar joint is the mutual solubility of the
two metals. This ensures that the materials can dissolve in each other. With a very
less solubility of both the mating materials, it becomes very difficult to join them. In
many cases, a third material, soluble with the two base materials is often employed
[6].
5.3.2 Intermetallic Compound
Intermetallic compounds (IMCs) are formed because of the limited solubility of
alloy components. The microstructural composition of the resultant IMC, depends
upon the mutual solubility, and it governs joint properties such as ductility, crack
sensitivity, and corrosion [6].
5.3.3 Weldability
The solubility and type of intermetallic compound, together decide the level of weldability of that dissimilar combination. Post the determination, the appropriate selection of external filling metal or buttering layers can be done in order to ensure a
smooth transition between the metals [6].
5.3.4 Melting Temperature
Large heat input in case of fusion welding may result in the melting of one metal
before another in dissimilar welding. The solidification and shrinkage of the metal
having a relatively higher melting temperature will induce stress in the other metal.
In this regard, the buttering of the filler metal is often carried out with a material
having an intermediate melting temperature. This helps in dealing with the problem
S. Sahu et al.
5.3 Influencing Factors for Dissimilar Welding
The development of various alloys has served many applications but welding them
together perfectly and repeatedly continues to be a difficult process. The factors
influencing a dissimilar joint have been discussed below:
5.3.1 Solubility
The most fundamental enabler of a dissimilar joint is the mutual solubility of the
two metals. This ensures that the materials can dissolve in each other. With a very
less solubility of both the mating materials, it becomes very difficult to join them. In
many cases, a third material, soluble with the two base materials is often employed
[6].
5.3.2 Intermetallic Compound
Intermetallic compounds (IMCs) are formed because of the limited solubility of
alloy components. The microstructural composition of the resultant IMC, depends
upon the mutual solubility, and it governs joint properties such as ductility, crack
sensitivity, and corrosion [6].
5.3.3 Weldability
The solubility and type of intermetallic compound, together decide the level of weldability of that dissimilar combination. Post the determination, the appropriate selection of external filling metal or buttering layers can be done in order to ensure a
smooth transition between the metals [6].
5.3.4 Melting Temperature
Large heat input in case of fusion welding may result in the melting of one metal
before another in dissimilar welding. The solidification and shrinkage of the metal
having a relatively higher melting temperature will induce stress in the other metal.
In this regard, the buttering of the filler metal is often carried out with a material
having an intermediate melting temperature. This helps in dealing with the problem