Stainless steel - when and where to use

thumb Stainless Steel Sheet Plate Strip Coil Circle Stainless Steel is widely used on various products and applications........but what is stainless steel?  What makes it unique ?  and why is it more expensive than other carbon steels?

Stainless steel has been around for over 100 years, and is manufactured by adding small percentages of different alloy elements to create hundreds of differing types.  To differentiate each type they are assigned numbers which relate to these particular elements, the most common types generally quoted are 304 and 316. Lasnek manufacture products from both these grades, and as such this document will focus on both these types.

Stainless steels are grouped into Austenitic, Ferritic, Duplex and Martensitic and each has its own set of performance characteristics and applications.  Both 304 and 316 fall into the Austenitic group which provides a good general level of corrosion resistance, can be easily formed, welded using basic techniques or machined without specialist equipment, making it an ideal material for numerous industries and usages.

austenitic and martensitic Formulae picture

The table below shows the chemical composition of various elements that make up these two versions of stainless steel, but first it should be noted that there are various numbering systems relating to the same type of stainless steel.

European no. International Steel no.  Typical Composition %
EN ASTM
(AISI)
Carbon
(c)
Chromium (Cr) Molybdenum (Mo) Nickel
(Ni)
Iron
(Fe)
1.4301 304 0.04% 18.10% 0.00% 8.30% Balance
1.4401 316 0.04% 17.20% 2.10% 10.20% Balance

 

At this point it’s worth highlighting how the cost of stainless steel is derived and why 304 is used in a higher percentage of products than the 316 variant.  The cost of stainless steel in an unfinished state comes from the addition of two variables, a baseline steel cost which is fixed at a steady constant, and an alloy surcharge based on the Nickel price.  This Nickel price fluctuates on the commodity market on a daily basis and theoretically the purchase price for stainless steel would alter continuously. Practically however, price from producers and stockholders alter at the end of each month, to average out any fluctuations in daily Nickel prices.

It can be seen from the table above that 316 has a higher percentage of Nickel and while seemingly small, this has a significant factor in cost difference between 316 and 304 – currently a 30-35% premium for the 316 variant.

Type 304 - 1.4301

 

This version of stainless steel is the most dominant of its type due to its combination of versatility and cost.  Used widely in the manufacturing of both consumer and industrial products, such as the Lasnek range of cable management, it offers an excellent compromise between finished price and corrosion properties. Its resistance in the majority of environments is far greater than that experienced from standard carbon steels even after surface treatments such as zinc plating or galvanising. 

The combination of these properties for 304 provide an all round solution for components used in hygienic environments. Typical industrial applications within food and beverage environments include auxiliary process equipment, such a cable conduits or enclosures, which are cleaned regularly but not in direct contact with any part of the process itself

Type 316 - 1.4401

This variant of stainless steel contains a higher percentage of Nickel and the addition of molybdenum, providing increased resistance to corrosion in environments where 304 is not suitable. Sometimes this grade of stainless steel can be referred to as ‘marine grade’ due to its historical usage in offshore and onshore coastal applications where the increase in resistance is required to withstand the chemical corrosion properties of salt. 

Apart from the issue of cost, 316 also has commercial limitations on availability, especially with reference to the finishes available.  However it's an ideal solution for use in environments where components may be subject to acid, salt, or aggressive chemicals. Within food preparation areas, 316 is generally the preferred grade for equipment or components that are in direct contact with foods, such as food preparation tables, or processing equipment such as cutting blades

Type Advantages Disadvantages
 304  
  • Availability of raw materials
  • Cost
  • Good corrosion resistance
  • Easy to work
  • Availability of pre-manufactured components
  • Suitable for most applications
  • Available in a majority of finishes
  • Not suitable for all applications
  • Hard to visually differentiate for 316
316
  • Excellent corrosion resistance
  • Good availability
  • Easy to work
  • Expensive
  • Reduced availability of components
  • Limited commercial finishes

About Lasnek

Lasnek is a world class manufacturer of stainless steel cable management products. Lasnek has consistently demonstrated commitment to quality, service and technical innovation by supplying manufacturing, installation and production companies with high quality solutions.

Contact Lasnek

Lasnek Ltd.
1 President Way
Luton, Bedfordshire, UK
Tel: +44 (0) 1582 425 777