Steels_ Metallurgy and Applications, Third Edition

Low-carbon strip steels 125

products were described in an earlier section and involve a variety of paint
or plastic formulations which are applied to zinc-coated steels. These coatings
provide enhanced corrosion resistance and are available in a wide range of colours
and surface textures.
The types of coating that are recommended for external use include PVC
Plastisol (200 ttm), PVF 2 (27 am), Silicone Polyester (25 ~tm) and Architectural
Polyester (25 ttm). 14s,149

Steel lintels

Lightweight steel lintels have now virtually replaced reinforced concrete lintels

in domestic housing. These components are specified in BS 5977: Part 2:1983

Specification for prefabricated lintels, which provides guidance on the design and

testing of all types of lintel for use in domestic buildings up to three storeys high.

This specification deals with post-galvanized lintels with heavy zinc coatings and

also those fabricated from pre-galvanized strip with minimum zinc coatings of

up to 600 g/m 2 (including both sides).

Other applications for strip steels

Domestic appliances

On page 94, information was provided on the production and properties of prefin-

ished strip, coated with various types of paint or plastic. During the late 1960s,

work was initiated on the use of pre-painted strip for the high-gloss, white

domestic appliance market and this proved to be a major commercial success.

Thus the majority of wrap-arounds for washing machines, refrigerators, dish

washers, domestic boilers and freezers are now produced from pre-painted strip,

providing the following benefits to the manufacturers:

1. Higher productivity.


2. Savings in floor space.


3. Reduced capital expenditure.


4. Elimination of the effluent problems associated with paint work.

The organic coating used for this type of work is a high-gloss polyester, 25 ttm

thick over a galvanized steel base, which provides a high flexibility/hardness ratio

and good resistance to elevated temperatures and detergents. Although the degree

of cold forming is not very severe for the majority of the components involved,

areas such as the ports for front-loading washing machines are subjected to a

limited drawing operation.

Steel drums

Steel drums, with capacities ranging from 25 to 210 litres, constitute a major

market for cold-reduced strip but one that is now facing major competition from