Stainless Steel Commonly Asked Questions

BS Stainless frequently get asked the same or similar kinds of questions in regards to our stainless steel products. Here are some of the top questions and our answers so that our customers remain informed:

  • What makes stainless steel “stainless”?

Stainless Steel has to contain at least 10.5% chromium and it is this which reacts with oxygen in the air to form a complex chrome-oxide surface layer which is invisible to the eye. It is this invisible layer which acts to prevent further oxygen from staining the surface of the stainless steel and leaving any rusting.

Obviously the higher the percentage of chromium the more resistant it is to rusting and staining.

  • What does 18/8 or 18/10 mean and any other numbers like this regarding stainless steel?

The first number refers to the percentage of chromium which is contained in the stainless steel so in the case of 18/8 you can see that there is 18% chromium present. As a rule stainless steel has to contain at least 10.5% chromium. The second number is the amount of nickel which is present in the stainless steel and so in the case of 18/8 there is 8% nickel.

What you need to bear in mind is that the higher the numbers generally the more resistant it is to corrosion and therefore the better it is.

  • Why are the same grades referred to with different reference numbers eg 304, 1.4301, 2333 ?

There are many different national steel designations dependent on country, usually you can find matching alternatives that suit the application locally. Some standards like EN list a grade that will meet many other national standards. These grades will have both specific chemical and physical compositions to suit a particular application or industry.

  • Is stainless steel magnetic?

This is a extremely common question which we are asked and one in which many people just assume that because it is a metal it is automati­cally magnetic but this isn’t the case. In answer to this question it is Yes and No. Stainless steel which contains nickel is not actually magnetic whereas the stainless steel which doesn’t contain any nickel and just chromium is.

  • Can stainless steel be welded?

This is why stainless steel is used within the building and construction industry. It is easily welded providing that the procedure of welding is changed. The rod or electrode which you use to weld must be stainless steel though.

  • What is the recycle content of stainless steel?

It can be recycled 100% it is simply melted down and then made into new stainless steel. Around 65-80% of stainless steel scrap is used to make brand new stainless steel. The melting range will differ according to the Steel Types:

Melting Range (Degrees Celsius)

Steel Types

1325-1400

254SMO 1

1370-1480

440A, 440C

1375-1400

316, 316L,

1385-1445

22051

1400-1420

301,

1400-1425

330, 321, 347,

1400-1440

17-4PH

1400-1450

201, 304, 304L, 305, 309, 310,

1425-1510

430, 446

1450-1510

420

1480-1530

409, 410, 416,

All this information is for general guidance and we hope you find interesting. If you need more specific information or advice its always worth contacting you local stainless steel advisory service. Ours is the Britsish Stainless Steel Advisory (BSSA), there is also the European Stainless Association (Euro Inox) and the Inter­national Stainless Steel Forum (ISSF) where you can seek information or local contacts.

For more information please contact us on +44 (0) 1254 811112 or email info@bsstainless.co.uk.

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