Metal Grade

[robbo1]

Is there any way of telling what grade of stainless or ally I have in front of me when the source of the material is unknown ?
i.e. Just bought two pieces of stainless from a car boot sale which I need to weld together but I don’t know if they are 304 or 316. Any idea's on how to tell ?

 

[Bsmith]

304 is usually used as the food/kitchen/hygene grade, 316 is marine. I would weld with 316 or 309 as there is no real way of telling what grade it is.

 

[hotrodder]

Ever wonder the phrase 'the acid test' came from? (probably somwhere else). If the stainless is non-magnetic then as said it'll almost certainly be either 304 or 316, weld with 308 or (preferably) 316. All the austenitic 300 series grades are very similar, there's small differences to optimise the corrosion resistance (and other properties) for different environments

Aluminium... if it's an extrusion (tube, box, angle, strip etc) then almost certainly a 6xxx series alloy, either 6063 or 6082. Castings will almost always be a high silicon alloy. More possibilities with sheet and plate... 1050, 3103, several 5xxx and 6xxx series. For sheet 1050 is a popular one (soft and very formable), 5251 is noticably harder and work hardens much more quickly. Plate most commonly 6082, treadplate is 5754

 

[robbo1]

WOW !! brilliant stuff thats the sort of info I was after hotrodder.