Er309 vs er312

[dogdog]

Ok... I have always been using ER309H and ER309L for TIG welding different stainless grade stuff... and planned it for welding some cast iron stuff when I get to it... So far it works great and have always been told to use ER309 for different grade of stainless work and stainless to mild steel and good for cast iron stuff. Then recently I think I see a few threads mentioning to use ER312 for this... ... So fine I got 10LB...

Any welder that can explain the differences ?

 

[MoonRise]

312 has about 10% more chromium in it that 308/309 and a bit less nickel. Carbon percentage is lower than in 309 but higher than in 308 (and much higher than in 308L).

312 - 0.15 C 2.00 Mn 1.00 Si 30.0 nom Cr 9.0 nom Ni

309 - 0.20 C 2.00 Mn 1.00 Si 22-24 Cr 12-15 Ni

308 - 0.08 C 2.00 Mn 1.00 Si 19-21 Cr 10-12 Ni

308L - 0.03 C 2.00 Mn 1.00 Si 19-21 Cr 10-12 Ni

single values are max allowed values in the material specs

Oh, and 312 by itself has only half of the elongation (~20%) before tensile failure compared to 308/309 (~45-55%).

The higher chromium percentage should lead to more ferrite formation in the weld (magnetic), especially when welding on non-stainless steels (no to minimal chromium content).

Cast iron? Welding cast iron (2-4% carbon typically) with a high chromium filler will probably lead to goodly amounts of really hard chromium carbides in the weld puddle as well as the iron carbides in the HAZ. Can you say "Ping!" (the sound of a hard metal cracking as it cools down from welding temperature back to room temperature)?

I lean towards the darn $$$ high nickel fillers if welding cast iron, along with lots of preheat (800F+).

YMMV.

 

[dogdog]

Thx for the explanation, I would have never knew how to interpert those numbers. I have always been told to use 309 for cast irons other than ni99 stuff... just recently learned about 312...

 

[dogdog]

312 has about 10% more chromium in it that 308/309 and a bit less nickel. Carbon percentage is lower than in 309 but higher than in 308 (and much higher than in 308L).

312 - 0.15 C 2.00 Mn 1.00 Si 30.0 nom Cr 9.0 nom Ni

309 - 0.20 C 2.00 Mn 1.00 Si 22-24 Cr 12-15 Ni

308 - 0.08 C 2.00 Mn 1.00 Si 19-21 Cr 10-12 Ni

308L - 0.03 C 2.00 Mn 1.00 Si 19-21 Cr 10-12 Ni

single values are max allowed values in the material specs

Oh, and 312 by itself has only half of the elongation (~20%) before tensile failure compared to 308/309 (~45-55%).

The higher chromium percentage should lead to more ferrite formation in the weld (magnetic), especially when welding on non-stainless steels (no to minimal chromium content).

Cast iron? Welding cast iron (2-4% carbon typically) with a high chromium filler will probably lead to goodly amounts of really hard chromium carbides in the weld puddle as well as the iron carbides in the HAZ. Can you say "Ping!" (the sound of a hard metal cracking as it cools down from welding temperature back to room temperature)?

I lean towards the darn $$$ high nickel fillers if welding cast iron, along with lots of preheat (800F+).

YMMV.

Dam 200+ views and only one reply, I guess you are the residential welder Not too sure about the cast iron part... that was what I have been told on people that weld cast iron manifold for turbos.... Except I never tried since I never got to that fun project.

 

[MoonRise]

Welding cast iron?

http://www.lincolnelectric.com/en-us/support/welding-how-to/Pages/welding-cast-iron-detail.aspx

http://www.lincolnelectric.com/en-us/support/welding-how-to/Pages/cracks-cast-iron-detail.aspx

http://www.lincolnelectric.com/en-u.../Pages/stick-electrodes-cast-iron-detail.aspx

Some more info about cast iron from ESAB (happens to be in their oxy-fuel handbook section, but still some good info about cast iron and how to deal with it in welding or brazing situations):

http://www.esabna.com/euweb/oxy_handbook/589oxy15_1.htm

Some more info about some different electrodes for arc welding on cast iron:

http://www.esabna.com/euweb/as_handbook/596as2_1.htm

re: the 'some folks told me' stuff

309 or 312 for welding some carbon steel to stainless steel or 'buttering' some carbon steel before then welding something stainless to that buttered layer or laying a first layer of high chromium filler onto a non-chromium containing steel before putting some $$$$$ hard-facing on? Sure.

But on cast iron? Nope, not me. Like I said, high nickel filler and high preheat (800-1200F).

Oh, and s-l-o-w cooling after the preheat and welding (on the order of only dropping temperature 50F per hour). Let's round off and say we did a 1100 F preheat and want to end up at 100 F at the end. That's a delta T of 1000 F, so at a rate of -50F/hr that gives a cooling time of 20 hours. Yeah, 20 hours.

Again, YMMV and all that.

 

[MoonRise]

Video with demonstration and explanations about welding cast iron.

 

[joe49]

Try cast iron rod with high temp flux, using O/A for cast iron repairs. No this is not brass or bronze.

 

[dogdog]

Try cast iron rod with high temp flux, using O/A for cast iron repairs. No this is not brass or bronze.

Yea, I am not really looking for cast iron repair at this moment.... that project is stuck until I get some funding or space to work on it.

The main purpose of this post is actually wanted to know the differences between ER309 VS ER312 and when to use what.

 

[Jlarson]

I use 309 on mild to stainless and 312 on medium carbon to stainless and medium to mild steel sometimes. This would be in non critical job shop, R&D, equipment repair type work that we do not on code applications.

 

[joe49]

Yea, I am not really looking for cast iron repair at this moment.... that project is stuck until I get some funding or space to work on it.

The main purpose of this post is actually wanted to know the differences between ER309 VS ER312 and when to use what.

Not what your 1st post said.

 

[dogdog]

Not what your 1st post said.

No worries, that is why I am correcting it, might be confusing when I don't organized my thoughts, if I do, I can be very dangerous.