Tin Free Steel

Tin Free Steel Tin free steel (TFS) is an electrolytic chrome plated steel consisting of a thin layer of chromium and a layer of chromium oxide deposited on a cold rolled steel base (black plate steel) which gives it a beautiful, lustrous metallic finish on both sides. It is also known as electrolytic chromium coated steel (ECCS). TFS offers outstanding corrosion resistance, lacquer adhesion as well as printability. It is an economical and high quality replacement for tinplate. It is not suitable for soldering and can only be used for welding after edge cleaning. ECCS must be lacquered on both surfaces. TFS has been developed to meet economic requirements, and excels tinplate in paintability, paint adhesion and economy. It is widely used for making beverage can and 18 litre cans. It is also used for making photographic film cases and as a protective material for optical fiber cables. The cross section of tin free coating on steel sheet is given in Fig 1. Fig 1 Cross section of tin free coating on steel sheet Features of tin free steel  The main features of tin free steel are given below: Paint adhesion – TFS has excellent paint adhesion properties which is far better than those of tinplate. The external surfaces of cans should be painted to prevent corrosion. The internal surfaces should also be painted to prevent corrosion except when the content is motor oil or cooking oil. Heat resistance – High temperature baking (around 400 deg C) causes neither discoloration nor deterioration in material properties in TFS steel. Resistance to black sulphide stain – TFS steel has excellent resistance to black sulphide stain. Due to it TFS is the most suitable material or making fish cans. Appearance – TFS steel provides the unique surface luster characteristic of metallic chromium even...