FLOWERS ARE BEAUTIFUL SO ARE SINCERE SMILES

GOOD MORNING

RUST

• Rust is a term for a series of Iron Oxides. • This phenomenon of Rust formation

happens when Iron is exposed to air or moisture.

• Rusting is the common term for corrosion of iron and its alloys, such as Steel.

RUSTING OF STEEL Rusting is oxidation or combining of the iron with

oxygen that occurs in the presence of moisture. Proceeds more rapidly where there is noticeable

dampness but it occurs in any air with a relative humidity higher than 70%.

Rusting occurs more rapidly in salt air and industrial atmosphere.

The rust is formed from the solid metal, reducing it size so that the members become weaker and loses any decorative finishes it might have.

The rust penetrate deeper as time passes on.

Corroded Steel

Rusting Of Steel

Mild Corrosion

Rusting Heavy rust on the links of a chain near the Golden Gate bridge in San Francisco; it was continuously exposed to moisture and salt-laden spray, causing surface breakdown, cracking, and flaking of the metal.

A rusted (and dirt-encrusted) bolt; note the surface pitting and gradual shape-deformation, caused by severe oxidation

Rust in pipes can result in brown and black water

STEEL PROTECTION

Among ways to protect steel from rust are:a) Painting – protect from rustb) Careful design – protect from rustc) Galvanizingd) Coating the steel with zince) Coating the steel zinc-pigmented paints

f) Bituminous coating. ( explained later in the ppt)

Painting the steel prevents rust but it must be done periodically.

Adding copper as an alloying element into carbon steel, could make it rust resistant. Prevention of rust can be done by careful

design to avoid a) pockets / crevices that hold water

b) spots that are inaccessible for repainting c) sharp edges that are difficult to coat with the

required thickness of paint

Painting the steel to protect it from rust.

ZINC USAGE FOR STEEL PROTECTION Usage of zinc to steel protection would be

able to prolong the life of steel. It adheres readily to the steel to form a tight

seal against the atmosphere and it corrodes slowly that the iron/steel.

Zinc continue to protect steel even after it has been eaten through in spots, because corrosion will take place in the zinc in preference to the ferrous metal.

BITUMINOUS COATING Used to protect iron & steel from the effects

of atmosphere, water or soil. Appearance and odor of bitumens make them

unsuitable to be protective coatings.

Conclusion

• Rust is associated with degradation of iron-based tools and structures. As rust has a much higher volume than the originating mass of iron, its build-up can also cause failure by forcing apart adjacent parts — a phenomenon sometimes known as "rust smacking”.

• Rust does cause an impact on metals which becomes very difficult to recycle and reuse.

Next time you see an iron nail or any metal that is coated with a rust, think of what you have learnt!!

MAKE YOUR LIFE BEAUTIFUL & MEANINGFUL

HOPE ALL OF YOU COULD UNDERSTAND THIS TOPIC