312 welding rod.

[Alistair Spence]

I read in a recent discussion elsewhere that Weldmold 880t and ER312 filler alloys are one and the same, so since 312 is less expensive buying that seems to make sense.

What I'm wondering is whether I should specifically be looking for the 312, or 312L (extra low carbon) version of the alloy?

The low carbon version has something to do with preventing/reducing the precipitation of carbon at grain boundaries, thereby reducing corrosion issues, I think, but I don't know much about this. 

Any insights on the metallurgical reasons for choosing one of these rods over the other would also be welcome.

Thanks,

Alistair Spence,

Seattle, WA.

[Jona Aal]

Alistair,

The L suffux is applied to stainless steel products (bar, rod, tube etc) that are designed to be welded, Too much carbon in the material causes chromium carbide to be formed at the grain boundaries, meaning there is deficiency in the parent material, enabling corrosion and then cracking at those boundaries. Because this compound is formed during the coolong stage of a weld it is almost impossible to prevent apart from using a specific filler that has extra chromium to replace that which is lost and by using a parent metal (with L suffix) that has less carbon than usual.

Normal stainless must only be machined although it is less common than it used to be due to the fact that welded fabrication is required for many products. The only welding rods you can get for stainless are ones for welding the material with an L after the alloy code.

It is possible to weld different grades of stainless together, and stainless to carbon steels. The rule of thumb is to use the rod that matches the higher grade parent metal. So if welding 304 to 316, then a 316 rod would be used.

There is a useful chart here:
http://www.mig-welding.co.uk/stainless.htm

Hope that helps,

Jona

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Jona Aal

H 01434 345 620
M 07940 731 375

[Wissahickon Cyclery]

Alistair,

I get mine from this place and this is a great data sheet that gives you info on 312.  I have bought both 312 and 312L and can not tell a difference.  Often the L stands for low carbon.  Other times it is for low fuming.  I have also seen it stand for low temperature.

They no longer offer 312L which is interesting.

There main page with what they have:  http://www.weldwire.net/product_categories/stainless-steel-tig-wire/

The 312 data page:  http://www.weldwire.net/wp-content/uploads/2013/08/ER312.pdf

Drew Guldalian

D.B.A. Engin Cycles
Wissahickon Cyclery
7837 Germantown Ave Phila,PA 19118
www.wiss-cycles.com
www.engincycles.com

[Alistair Spence]

On Sat, Feb 21, 2015 at 12:38 PM, Jona Aal <jona...@gmail.com> wrote:

Alistair,

The L suffux is applied to stainless steel products (bar, rod, tube etc) that are designed to be welded, Too much carbon in the material causes chromium carbide to be formed at the grain boundaries, meaning there is deficiency in the parent material, enabling corrosion and then cracking at those boundaries. Because this compound is formed during the coolong stage of a weld it is almost impossible to prevent apart from using a specific filler that has extra chromium to replace that which is lost and by using a parent metal (with L suffix) that has less carbon than usual.

Normal stainless must only be machined although it is less common than it used to be due to the fact that welded fabrication is required for many products. The only welding rods you can get for stainless are ones for welding the material with an L after the alloy code.

It is possible to weld different grades of stainless together, and stainless to carbon steels. The rule of thumb is to use the rod that matches the higher grade parent metal. So if welding 304 to 316, then a 316 rod would be used.

There is a useful chart here:
http://www.mig-welding.co.uk/stainless.htm

Hope that helps,

That is helpful, thanks. I wasn't clear in my question, I'm not actually welding stainless, more typically 4130, which some have been using the 312 rod to weld. I've seen that rod listed as 312, and 312L (here in the US anyway), and I was just wondering if using one of those in particular was preferred when it came to welding bike frames/stems etc.

Alistair.

[Michael Catano]

Can you link to the discussion of 312 v 880t?

Thanks

m

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[Alistair Spence]

On Sat, Feb 21, 2015 at 12:59 PM, Wissahickon Cyclery <wissc...@gmail.com> wrote:

Alistair,

I get mine from this place and this is a great data sheet that gives you info on 312.  I have bought both 312 and 312L and can not tell a difference.  Often the L stands for low carbon.  Other times it is for low fuming.  I have also seen it stand for low temperature.

They no longer offer 312L which is interesting.

There main page with what they have:  http://www.weldwire.net/product_categories/stainless-steel-tig-wire/

The 312 data page:  http://www.weldwire.net/wp-content/uploads/2013/08/ER312.pdf

 Thanks Drew,

good point about the L suffix. In some metals it refers to leaded, for freer machining properties. I guess context is key here.

Alistair.

[Alistair Spence]

On Sat, Feb 21, 2015 at 4:45 PM, Michael Catano <shuffl...@gmail.com> wrote:

Can you link to the discussion of 312 v 880t?

Thanks

Michael,

here you go, http://www.velocipedesalon.com/forum/f10/weld-mold-880-tig-wire-uk-39331.html

I should mention that I received some off list responses to my questions in that thread confirming very specifically that they are the same rod.

Alistair.

 

[roadrash...@gmail.com]

Alistair we've used both and had them both pass CEN tests with insignificant differences