What are the Technological properties of metals?

The technological properties of metal area those properties, which completely define the behavior in shaping, forming, and fabrication operation during the manufacturing process.

1. Malleability
2. Machinability
3. Weldability
4. Castability
5. Formability

Malleability:-

The term ‘malleability ‘ may be defined as the property of metal by virtue of which it can be deformed into thin sheets by rolling and hammering without rupture. it depends upon the crystal structure of metals. All the metals, having small grain sizes, are used for very thin sheets, whereas the metals having large grain sizes are used for thick sheets. The Rolling of aluminium foil is the best example of malleability.

A metal’s malleability can be measured by how much pressure (compressive stress) it can withstand without breaking. Differences in malleability among different metals are due to variances in their crystal structures.

The following common metals have malleability in decreasing order-

Gold – Silver – Aluminium – Copper – Tin – Platinum – Lead – Zinc – Iron – Nickel

Fig.:- Convert into a thin sheet by the hammering process

Machinability:-

The term “machinability” may be defined as the property of a metal, Which indicates the ease with which it can be cut or removed by the cutting tools in various machining operations such as turning, drilling, boring, milling, etc. It depends upon the mechanical and physical properties of metal, the chemical composition of the metal, the microstructure of the metals, and cutting conditions.

Factors affecting machinability-

• The hardness of metals.
• Composition of the metals.
• Grain size and microstructure of metals.
• Work-Hardening of metals.
• Type and quality of machine use.
• Size, shape, and velocity of cut.
• Quality and lubricant used during operation.
• Coefficient of friction between chip and tool.
• Shearing strength of the workpiece.

Weldability:–

The term “Weldability” may be defined as the property of metals, which indicates the ease with which two similar or dissimilar metals are joined by fusion and with or without the use of filler material.

A metal has good weldability if it can be easily welded in a fabricated structure.

Welding Process

The various factors that affected the weldability or metal are:

• Composition of metals
• Brittleness and strength of the metal at elevated temperature.
• Thermal property of the metal.
• Welding techniques, fluxing material, and filler material.

Castability:-

The term “Castability” may be defined as the property of metals, which indicates the ease with which it is casted into the different shapes and sizes from their liquid state.

Formability or workability:-

The term “Formability or workability” may be defined as the property of metals, which indicates the ease with which it can be formed into different shapes and sizes.

The metals with small grain sizes are suitable for shallow forming, while metals with relatively large grain sizes are suitable for heavy forming. The distortion of grains is an important factor that affects the formability of metals, as the distortion of grains takes place due to hot working on metal.