Welding Tips and Tricks

Off and on I've heard about using 309 stainless for mild steel welding.

Otto, what are your thoughts on this...

I've heard you don't have to clean your metal near as good and it will keep out some porosity, unlike ER70s6

Whats everybody's thought on this...

Thanks

John

One more thing....

I found a good deal on 20 lbs of ER 309 tig rod and I was thinking if I should buy it or not

I am mainly gonna be welding plain old steel....

Thanks John

I'm talking 3/32 in dia by 36 in long ER 309 tig rod
I've got a 160 amp tig welder, and I'm mainly gonna be welding plain old steel
Should I buy 20 lb of this rod
Thanks
John

John, It normally sells for around $15-20 a lb. and yes you can weld non-spec welds on mild steel with it. It works nice on cheap chinese steel where ER70s-2 and s-6 bring up a lot of porosity. I use it quite often when I need to weld carbon to stainless. It seems to be pretty forgiving when it's impossible to clean your steel to shiny clean. Not knowing what the price is, it's pretty hard to say if it's worth buying or not though.

Len

I often use 309 on a root-pass on carbon steel (CorTen, most often), when the weld has to be vacuum tight but I can't properly clean the back side of the weld for mill-scale and light rust. I'll often have a repair section requiring a backing bar, but must only tack it and dam it until another repair is proved, in case I have to go back in. Assuming the other repair passes, I'd rather not cut the tacks and backing bar out to re-clean, and a 309 root will greatly reduce the chances of porosity in the root and saves work. I still have to fill and cap it with 70S-2, but because it's a specification, not because I doubt the 309 weld in any way.

I also use 309 to weld cast steel to rolled steel, to reduce cracking. It does not always prevent it, but if it cracks, the cast is "buttered", and a grind/reweld will usually hold the second time, especially if completed while the metal is still quite hot.

If the price is right, I'd buy. Beware of using it in critical welds, though, especially for a customer, as in a critical weld, the properties may not adequately match the use.

Merry Christmas,

Steve S

otto

would/should 309 also be used on CORTEN in outside applications e.g. outdoor sculptures and or shipping containers?

i was guessing so because, while the weathering steel develops resistance to corrosion the weld metal will not.

michael

winston weldall wrote:otto

would/should 309 also be used on CORTEN in outside applications e.g. outdoor sculptures and or shipping containers?

i was guessing so because, while the weathering steel develops resistance to corrosion the weld metal will not.

michael

Interesting question. In outdoor scuplture, on an unpainted surface there will be a color-match problem (unless maybe a thin cap pass of 70S-2 is used).

Shipping containers are held to rigorous standards of construction and testing, and a design using 309 would have to go through the testing process start to finish. I think the solution for shipping containers is simply a "retirement age", making many available on the market for use as storage containers, portable offices, etc., and interestingly, in the old shipping containers I've seen, the welds are the strong point.

Just thoughts and observations.

Steve S

@Steve,
Are the outer tanks made of Cor-Ten on a cryo trailer?

I live about ten miles from the first building ever built out of Cor-Ten and about 25 miles from the US Steel building, also made from it. I've delivered to the one closest to home but didn't take note if anything was welded or not. I had a few friends who have now pasted that worked on it's development.

I grew up surrounded by Mill Hunkies and the original Aluminum plant is only about 4 miles from my home. My closest neighbor growing up worked for Alcoa and worked hand and hand with Linde (Union Carbide) to develop Heliarc welding. He was an amazing welder and craftsman with many patents to his credit. He also made plum wine that would make a bronze statue sh!t faced.

Len

So, I got 20 lb of 3/32 ER 309 for 120 bucks and free shipping...

Braehill wrote:@Steve,
Are the outer tanks made of Cor-Ten on a cryo trailer?
Len

I don't think so, at least in the present fleet. CorTen is what is now specified for all carbon-steel parts used in repair/replacement, but I'm not sure the alloy existed 30-40 years ago when this fleet was built.

In fact, the earliest of the Gardner series were carbon steel throughout the outer vessel, before the last outer section was changed to 304 (a major mistake, in my opinion, though they had no reason to foresee this at the time).

There is a new series supposed to be under construction now or soon to replace the Wilkes-Barre series as they are retired, and I'll bet good money the stainless components of the outer vessel will be duplex stainless to eliminate the possibility of corrosion stress cracking. I've fed the engineering department a good 200 pages of evidence to support this choice, and documented the phenomenon in over 50% of trailers over 30 years of age that I have encountered.

I'll also bet good money I'll never see one lick of credit for the decision.

Such is life.

Steve S

@Steve,
The first one that cracks will be the only one you'll get (blame) credit for.

The use of Cor-Ten in buildings started as early as the 70"s, if not before. I know that at different times painting it has caused it to fail because the oxidation wasn't allowed to form and it rusted from within. That would make using it in a repair that will be painted a poor choice in my mind. I guess as long as the vacuum holds there can be no moisture to come from the inside, but small paint defects would be crack in the dike.

But hey I'm not an engineer, but I did stay in a Holiday Inn Express. I just put stuff together with whatever some 20 something year old kid says will work, and so do you.

Len

Len,

I suppose CorTen was specified first for working doublers, where the backside can't be painted, and the buildup of scale can actually tear the doubler off the tank.

I've also discovered that the paints we use are porous at a microscopic level. Perhaps that allows the formation of the protective layer? I'm no engineer, though, and as you said, I use what they say use. I've often said, when questioned why something is done a certain way, "I sign the checks on the back... ask the guy who signs the front."

Or, more recently, I'll say, "That's above my pay grade..."

Steve S

@ John,
As my Pap would say, "cheap at twice the price".

Len

AKweldshop wrote:So, I got 20 lb of 3/32 ER 309 for 120 bucks and free shipping...

And you didn't send me any for X-mas?