Why we use only marine grade 316 steel for our heaters

Over the years, slick advertising campaigns have equated stainless steel construction with durability and quality. While stainless steel is an excellent material to use in certain products, it is important to realize that – not all stainless steel is created equal.

Different Grades of Stainless Steel

Stainless steel comes in many different grades. In manufacturing, different grades of stainless steel are used depending on what kind of stresses a particular product or structure must stand up to.

Problems arise when the customer assumes a stainless-steel product will stand up to a specific environment and it falls short. Because of this, it is recommended that you familiarise yourself with the different grades of stainless steel.

But don’t worry, you do not have to go away and research all the grades of stainless steel. For outdoor heaters, you just need to know about 304 grade and 316 grade.

The New Zealand Problem: When your 304 should be 316

In New Zealand, most of our outdoor products and appliances are imported from overseas. These products almost exclusively use 304 grade stainless steel in their construction. While this is okay in some environments, these products are susceptible to deterioration in saline environments - like coastal settlements.

With much of NZ being coastal, this is a major issue. 304 grade is a cheaper material and through prolonged exposure in loses its lustre and can rust. 316 grade however contains higher levels of the alloy molybdenum. Molybdenum significantly improves corrosion resistance in saline environments.

Kelray Heaters are the only outdoor heaters that use 316 grade stainless steel (including all small nuts, bolts and components).