Sherardize

Corrosion in Steel - The Consequences


Failure to control corrosion will lead to increased costs, reduced safety and negative environmental impact. The number of accidents to which corrosion has been attributed is extensive, examples of such include the following:-

  • North Sea platform collapse in 1970 due to stress corrosion in deluge pipework. 167 lives lost.
  • Bhopal, India in 1984. An iron catalyst produced by corrosion contributed to a catastrophic gas escape, estimated loss of 4000 lives and injuries to 500,000.
  • Switzerland in 1985, the collapse of a 200 ton concrete ceiling of an indoor swimming pool, 12 people lost their lives.
  • The disintegration of a Boeing 737 in Taiwan in 1981 was due to extensive corrosion damage in lower fuselage structures, resulting in 110 fatalities.
  • An oil spill in Canada in 1997 was caused by a leak in a corroded pipeline, 35 000 litres of oil escaped in one night, causing large scale environmental damage.

Corrosion Control

Introduction

The process of mass producing steel was discovered in the mid 1800's by Sir Henry Bessemer, an Englishman who established the first steelworks in Sheffield. His discovery helped lead to the industrial revolution and steel is now one of the most common materials in the world. However, with its discovery came the problem of corrosion and therefore corrosion control.

Corrosion In Steel - The Cause

Corrosion - the deterioration of a material - is the result of the chemical interaction of a metal with its environment. Corrosion damage can take many forms, the rate and type of attack dependent on the physical and chemical conditions of the environment.

Corrosion Control - Sherardizing

It has been estimated that a quarter of all corrosion problems could be prevented easily by using well established techniques such as Sherardizing.

Sherardizing may be used as stand alone system in a purely sacrificial role, or as a component of a sacrificial and barrier protective system by the application of an organic or non-ferrous topcoat. Base materials suitable for Sherardizing are unalloyed carbon steel, low alloy steels, sintered material, malleable grey and cast iron.