Tech question A2 vs A4 stainless steel

[PurleySquire]

A very simple tech question for the metalologists.

I have been using stainless fittings on my bikes and the benefits are mainfold. Oh the joy of taking apart items that look great and haven't welded themselves up with rust. Best of all you can source fixings from companies like ScrewFix for pocket change.

The question I need answering is; What is the difference or benefits of A2 against A4 stainless steel?

I imagine it has much to do with the composition of the alloy, percentage of chromium present, etc.

For my purposes it needs to be able to withstand salted roads, take cold temperatures and look pretty.

 

[PurleySquire]

Might have found the answer

... it is not a question of material strength, but a matter of resistance to corrosion. Due to its higher Molybden content, A4 Stainless Steel is more corrosion-proof against agressive substances. For this reason, it is widely used in the chemical industry, as well as the food processing industry. All tanks, pipes and valves coming into contact with food are made of A4 Stainless Steel.

 

[xerxes]

http://www.graphskill.co.uk/wordpre...ainless-steel-a2-a4-in-relation-to-fasteners/

A4 is more corrosion resistant, "Marine grade" stainless.

 

[lumos2000]

you could aslo keep an eye out for 316 stainless used in marine and body piercing industrys

 

[PurleySquire]

Thanks chaps

Thanks for the suggestions, much appreciated.

One of the websites I came across said similar "A2 for above the waterline and A4 for below".

 

[integerspin]

I have been using stainless fittings on my bikes
For my purposes it needs to be able to withstand salted roads, take cold temperatures and look pretty.

Don't forget the anti seize and Duralac.

 

[xerxes]

Don't forget the anti seize and Duralac.

I use Copper Grease (Coppaslip) for assembly on threads, seat posts etc. Costs about £5.00 for a big 500g tub.

 

[SNAKEBITER]

Don't forget that using grease on threads will affect the torque of the fastener.
I.E. it reduces friction meaning that if you tighten it to 10Nm, it will not be as secure as a dry 10Nm.

If you know what I mean.
I know what I mean but it's trying to get it over

 

[unkleGsif]

I know what I mean but it's trying to get it over

I'm a bit like that, but with my Mrs and my leg :shock:



G