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How to Choose the Right Stainless Steel Grades

Posted: 1st October 2014

With over 60 stainless steel grades and many products to choose from, it’s easy to get confused. Here at Midway Metals, we can advise you which grade to choose to best suit your project.

Following are a few of the basic factors you should be looking at in order to select a product that will meet all of your expectations.

For more detailed recommendations, don’t hesitate to contact our team of professionals and we will help you find just the right product.

Choosing the right stainless steel product

When choosing stainless steel the basic categories are:

The following are the most important factors when considering which steel you need:

Corrosion resistance

The environment that the stainless steel product will be installed in is key – the main considerations are atmospheric conditions, the concentration levels of particular chemicals such as chloride and the presence of acid.In a low corrosive environment a general-purpose austenitic stainless steel grade like 303 or 304 will do; in more highly corrosive environments high in acidic content, chlorine or seawater then 316, 904L or 2205 would be required.

Heat resistance

The temperature of the environment is also an important factor. High temperatures like those found in furnace environments (900 – 1175C) accelerate corrosion rates and exert extra pressures on stainless steel products. They require a higher grade of stainless steel especially designed for heat resistance, such as 321 or 253MA.

Cryogenic resistance

Very low (cryogenic) temperatures are another factor. Austenitic stainless steels can be used effectively at very low temperatures because they retain higher tensile strengths than those at ambient temperatures. While there is a slight degrading of toughness at this temperature these steels have been used successfully in temperatures as low as-161°C.

Magnetic response

Austenitic grades have a low magnetic response or ‘relative magnetic permeability’; those containing higher nickel content such as the 316 or 310 grades are guaranteed non-magnetic in any conditions.The ferritic and martensitic stainless steel grades (400 series) have high permeabilities and are classed as ‘ferromagnetic’.Duplex grades like 2101 and 2205 are also ferromagnetic.

Strength required

Steel strength is an important consideration before selecting your grade, but this is a complicated one. Your requirement will depend on the steel’s purpose and the type of environment it is being installed in. High strength stainless steels are available in austenitic, duplex, and martensitic categories but the strongest steel may not always be suitable. For instance, high strength austenitic steels produced by work hardening are not suitable where welding is carried out, as it softens the steel.

Form of product

Whether your stainless steel product is a sheet, bar, tube or other form will affect the grade you require. Not all grades are available in all product forms and sizes. The austenitic stainless steels are very versatile and within this large rangeyou canfind all product forms with a wide choice of dimensions. Ferritic steels are more common in sheet form and martensitic steels are more commonly found as solid bars.

Special requirements

When installing stainless steel products there may be special requirements that change the grade of the steel you require. As well as the basic temperature, corrosion and strength considerations, you may require totally non-magnetic properties in your steel, need products that are especially well-suited to welding or capable of a high degree of forming, or simply need a special aesthetic effect.

Cost

Of course cost is always a factor and must be balanced with all the other considerations. Sometimes the best technical option is too expensive, but make sure that you assess cost on a life cycle basis rather than on the initial price alone. Stainless steel products tend to have a long life so higher quality steel with a higher upfront cost can often be justified on this basis.

 

Contact Us Today!

As Australia’s largest independent stainless steel stockist, Midway Metals has become the trusted name for all types of stainless steel grades.

We have been supplying the Asia Pacific region for many years. Check our selection of high quality stainless steel products online now.

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