Technical Data

Why stainless steel?

Exceptional corrosion resistance, durability, sleek and stylish look and complete recyclability have made stainless steel a popular material for industrial and domestic applications.

What is stainless steel?

Stainless steel is a generic term of a group of corrosion resistant steels containing a minimum of 10.5% of chromium. Varying additions of nickel, molybdenum, titanium, niobium and other elements many also be present.

Type of stainless steel

There are five basic categories of stainless steels: austenitic, ferritic, duplex, Martensitic and precipitation hardening.

The austenitic grades are non-magnetic and in addition to chromium, typically at the 18% level, contain nickel (which improves fabrication and corrosion resistance) are the most widely used group of stainless steels.

The basic composition of the austenitic stainless steel is 18% Chromium and 8% nickel.  This is grade 304, sometimes referred to as 18/8. If additional corrosion resistance is required 2% molybdenum is added, termed as grade 316.

Grade 304 is the most common stainless steel used for multiple applications but inadequate for many marine applications. Grade 316 with better corrosion resistance can meet the requirement of marine applications.

The typical composition of 304 and 316 stainless steel are as following, which some other institutes use a range instead of a figure for the per centage.

Grade

C

Cr

Ni

Mo

304

0.05%

18.50%

8.50%

0.00%

316

0.05%

17.00%

11%

2.10%

 

‘Tea Staining’ of stainless steel

The brown discolouration of stainless steel caused by incorrect specification, fabrication or handling in coastal environment is loosely known as ‘Tea Staining’. Wind exposure, industrial pollution, hot temperatures and etc. environmental factors could contribute to ‘Tea Staining’ as well. ‘Tea Staining’ is controllable by regularly washing, cleaning and protecting with stainless steel protective products. ‘Tea Staining’ does not affect the structural integrity of the material but appearance only.