stainless steel 'A2-70 THE' grade? Is this suitable

[matnoo]

stainless steel \'A2-70 THE\' grade? Is this suitable

I have some bolts marked 'A2-70 THE' are these marine grade? There are several grades of stainless steel and I want to know if this is suitable. The last stainless steel transom bolts look like theyve gone 10 rounds with tyson... unsuitable grade!

What other grades are there? and why?

Mat

 

[VicS]

Re: stainless steel \'A2-70 THE\' grade? Is this suitable

It is a type 304 stainless. Ok away from the marine environment or inside the boat. Best not used where it will come in contact with sea water and definitely not below the water line.

A4, or 316, is the one to use if in contact with seawater.

 

[Channel Ribs]

Re: stainless steel \'A2-70 THE\' grade? Is this suitable

I agree and use only A4 myself, but many people would be happy using A2 for allmost all boat fixings. There is a local swindler which stocks only A2.

 

[DAVIDO]

Re: stainless steel \'A2-70 THE\' grade? Is this suitable

Main reason is 304 is easier to machine hence cheaper.

 

[richardandtracy]

Re: stainless steel \'A2-70 THE\' grade? Is this suitable

A2 = 304 type stainless
A4 = 316 type & much more 'stainless' in the sea due to higher chrome & nickle content.
'-70' is a strength indicator in daN/mm^2 (1 daN = 10 Newtons or approximately 1kg). This can be -50, -70 or -80 in accordance with BS 6105. The normal strength of 700 N.mm^2 gives a tensile breaking load of 3.5 tonnes for an M10 bolt/screw. The yield strength is 450 N/mm^2, or 2.2 tonnes for an M10.

Regards

Richard.

 

[Birdseye]

Re: stainless steel \'A2-70 THE\' grade? Is this suitable

[ QUOTE ]
Main reason is 304 is easier to machine hence cheaper.

[/ QUOTE ]

No it isnt - the extra cost comes from the molybdenum and extra nickel that it contains. Macining is no different.

The THE is most likely the manufacturer. I dont recognise the name but thesde days its something when you get a name at all. Grade 70 too so these are not the typical chandlery bolts. Impressive

 

[euromilam]

Re: stainless steel \'A2-70 THE\' grade? Is this suitable

MILAM:
stainless-steel machinery, production of individual solutions, world- wide delivery and after sales-services

EuroMilaM

 

[Roberto]

Re: stainless steel \'A2-70 THE\' grade? Is this suitable

IIRC, THE comes from french meaning Tête Hexagonale (six pan head), letter E should mean the thread runs along the full length of the bolt.
THP instead are six pan head bolts only partially threaded.