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Unusual uses for your products

As a manufacturer do you ever find your products used in a way you never dreamed of?

We are starting to build up a catalogue of these – to help tell the story

Recently a gentleman bought an M30 stainless steel nut – but he only wanted one, so I asked why.

Hex nut“I’m just an amateur hobbyist so I don’t have any magical costumes or anything to pose with, but I’ll see what I could put together once I’ve practised a bit, maybe a short video? The effect will be pretty anti-logic, e.g a bolt will be suddenly appear on a piece of rope, then the rope will attach and un-attach itself from the bolt, and disappear/reappear etc. Will take some practice but it should be fun if all goes to plan”

I can’t wait for the video – watch this space

Another recent purchase was for three stainless steel u-bolts. Upon enquiry we found they were to hold wing mirrors on to a racing car – we are waiting to see if the purchaser wins his race

U-bolts again:

U-bolt“I have used the U-bolts on a mounting frame for a solar panel, and it has worked out really well (the U-bolts hold the solar panel to a 50mm OD Alloy Tube with a T-Piece on it that allows me to put the panel on the top of a vertical 50mm pole, and I can therefore rotate and tilt the panel in any direction for maximum solar effect (it will be on top of my canal boat which could be facing to any point on the compass)”

He has since ordered more for additional panels 🙂

And how about using studding and fasteners on a boat?

Thanks for supplying the studding etc so swiftly.  If only every on-line retailer worked to the same timings!  I am using the studding as tie rods in the new oak cabin sides of the 1919 studdingNewlyn Lugger boat (google Ocean Pride PZ134 for previous pictures)  that I am refitting.  I will no doubt be in touch for more fastenings as I progress

We would love to hear more stories like this, for our products and any one else’s really. Let’s build a list of these stories – add your story to the comments section

Grades of stainless steel A2, A4 in relation to fasteners

There are a number of different grades of stainless steel, and I want to look at the properties of two, namely A2 and A4 and discuss where they can be used.

Firstly though, lets define Stainless Steel: Also known as inox steel from the French “inoxydable” is a steel alloy with a minimum of 10.5 % chromium. The chromium helps the alloy to resist staining and corrosion. The main point to make here is that it helps resist corrosion, it does not prevent it. Perhaps we could say “A highly corrosion-resistant grade of steel”

Stainless steel differs from carbon steel by the amount of chromium present. Unprotected carbon steel rusts readily when exposed to air and moisture. This iron oxide film (the rust) accelerates corrosion by forming more iron oxide. Stainless steels contain sufficient chromium to form a passive film of chromium oxide, which prevents further surface corrosion and blocks corrosion from spreading into the metal’s internal structure.

Passivation only occurs if the mixture of chromium is high enough.

Other alloying elements are added to enhance the structure and properties such as formability, strength and cryogenic toughness. These include metals such as:

  • Nickel
  • Molybdenum
  • Titanium
  • Copper

Non-metal additions are also made, the main ones being:

  • Carbon
  • Nitrogen

The British Stainless Steel Association discuss the ‘discovery’ of stainless steel here: http://bit.ly/ex4yNI

Stainless steel, when used for fasteners (nuts, bolts, screws etc) have British standards. BSENISO 3506 replaces BS6105. Part 1 covers bolts, screw and studs, part 2 nuts and part 4 tapping screws.

To all intents and purposes, when we see type A2 stainless steel, we can also call it Type 304. Likewise A4 grade can be called type 316 – but more:

A2 > Type 304 can also be called 18/8 because it ‘approximately’ contains 18% Chromium and 8 % nickel

So, A2 (304, 18/8) is an austenitic steel and is non-magnetic. The chromium provides a corrosion and oxidation resistance, however it can tarnish. It is immune to foodstuffs, sterilizing solutions, most organic chemicals and dyestuffs, also a wide variety of inorganic chemicals. As such it is used extensively for sinks, tabletops, stoves, refrigerators , pots, pans dairy equipment, brewing industry, fruit industry, food processing plants, dye tanks, pipelines,  and more

However, for marine conditions you need more resistance to corrosion. Adding molybdenum (2-3%) to the mix provides this extra cover – and gives us the A4 grade

A4 grade then is also austenitic, non magnetic and suitable for all the situations as A2 BUT has the added advantage of being suitable for marine solutions. Often called Marine Grade stainless steel. The molybdenum increases the corrosion resistance to withstand attack from many industrial chemicals and solvents and of course, chlorides. Used in the production of inks, photographic chemicals, surgical implants, and the marine environment

Both A2 and A4 grades come in three property classes: 50 (soft) , 70 (cold-worked) & 80 (high-strength) – the most common of which is the 70 class which is cold drawn” from bar stock.

These classes have different mechanical properties. For example A2-70 has a tensile strength of 700 Nmm-2 and 450 Nmm-2 proof stress. The BSAA has some good comparison details here: http://bit.ly/eXXLZP, and there are more tables of properties here: http://bit.ly/70aDdB

In summary, stainless steel fasteners should be used when you need to minimise the risk from corrosion. A2 is a very good grade for this, but when you need that little bit more, for example in a marine environment, then it is best to go for A4

You can see a specification sheet here: DOCUMENTS & BROCHURES : When you get their click Log In As Guest

Extra Reading:

http://home.cogeco.ca/~mquill/stainless.html : A discussion of stainless steel for rigging

http://www.cip.ukcentre.com/rust2.htm: Chloride attack on Stainless Steel

http://www.mcnallyinstitute.com/04-html/4-1.html: Corrosion problems with Stainless Steel

 

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