Welding Tips and Tricks

Hello,
Brand new to the site, but I've been a journeyman Millwright fro 17 years. In the foundry where I work I from time to time have to do some welding/repair on 1/4" to 1/2" Stainless plate. We generally use 1/8" 312-16 Crown Alloy rod, running 105 amps or so DC-RP. Any tricks to controlling the heat build up without sacrificing large amounts of time? WE have a couple of 1000 gallon quench tanks used for heat treating that get stress cracked. The main problem is the running the puddle and it starts to sag, bulge through the middle, and undercut the toes as we move through the process.

Vertical stainless is one place I think a remote amp control belongs in stick-welding, because you're right. When your amps are set for a good start, you get a good quality inch or so, then the heat-soak causes sagging, and even drip-out.

When your amps are set for a good run, you get a cold start with slag inclusions.

Lower amps with a hefty preheat can help... set the machine for a good run (85-90 amps, if you're comfortable), and pre-heat your starting point to brown - dull orange, and be ready to move when you strike up.

Your mileage may vary... (I've not done this specific application.)

Steve S

bobby_dean75 wrote:Hello,
Brand new to the site, but I've been a journeyman Millwright fro 17 years. In the foundry where I work I from time to time have to do some welding/repair on 1/4" to 1/2" Stainless plate. We generally use 1/8" 312-16 Crown Alloy rod, running 105 amps or so DC-RP. Any tricks to controlling the heat build up without sacrificing large amounts of time? WE have a couple of 1000 gallon quench tanks used for heat treating that get stress cracked. The main problem is the running the puddle and it starts to sag, bulge through the middle, and undercut the toes as we move through the process.

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Bobby_dean75.

Welcome.

On what alloy types of stainless steel plate are you welding/repairing?

Tanks.
Alexa

Alexa wrote:

bobby_dean75 wrote:Hello,
Brand new to the site, but I've been a journeyman Millwright fro 17 years. In the foundry where I work I from time to time have to do some welding/repair on 1/4" to 1/2" Stainless plate. We generally use 1/8" 312-16 Crown Alloy rod, running 105 amps or so DC-RP. Any tricks to controlling the heat build up without sacrificing large amounts of time? WE have a couple of 1000 gallon quench tanks used for heat treating that get stress cracked. The main problem is the running the puddle and it starts to sag, bulge through the middle, and undercut the toes as we move through the process.

=====

Bobby_dean75.

Welcome.

On what alloy types of stainless steel plate are you welding/repairing?

Tanks.
Alexa

It's hard to say, due to the age of the equipment, also the environment is poor in general in that department so finding any markings indicating alloy is pretty difficult. I'm going to guess 304, as I've seen that laying around over the years in the fab shop area. I've done more stainless welding on 14 and 12 ga. sheet than plate, but have run 3/32 down hand DC-EN mostly at around 80amps or so. Thanks for your help, Bobby.

Otto Nobedder wrote:Vertical stainless is one place I think a remote amp control belongs in stick-welding, because you're right. When your amps are set for a good start, you get a good quality inch or so, then the heat-soak causes sagging, and even drip-out.

When your amps are set for a good run, you get a cold start with slag inclusions.

Lower amps with a hefty preheat can help... set the machine for a good run (85-90 amps, if you're comfortable), and pre-heat your starting point to brown - dull orange, and be ready to move when you strike up.

Your mileage may vary... (I've not done this specific application.)

Steve S

You're saying preheat and run that amperage with 1/8" rod? Now what about the type of rod, 312-16, is that appropriate, or should I be looking at a different rod ? Thanks again for the info, Bobby.

Bobby_dean75.

With the austenitic stainless steels (example: 304, 316, etc.) there is the additional precaution to avoid overheating these alloys during welding. The procedures often require the temperature of the joint, between weld passes, to not exceed 300 degrees F. In addition, to help reduce the heat buildup, to use single passes, instead of weaves.

Tanks.
Alexa

That 312-16 rod is fine, but you may find easier welding with 308lsi, especially on older (read used and abused) materials. There isn't an engineer on site who knows the alloy your welding on?

I would suspect a 300- series. 316 has a higher corrosion resistance than 304, particularly for salts and caustics. 308 will weld either, as will the 312-16 rod, but if no one at the plant can give you a "required" filler, the 308lsi will perform better for you, as the weldor. The "si" refers to silicon, same as the "S" in a carbon TIG wire like ER70S-6, and it provides scavenging for impurities in this "well used" parent metal.

When the weld is important, I only buy Lincoln brand... Tried many, and they are just more predictable and constant one rod to the next, one batch to the next. Also, Stainless stick-rod does not tolerate moisture at all (I've had the flux literally "explode" when damp). That's why they come in sealed metal cans. Keep 'em in a rod oven once opened.

Steve S

Removed.

Otto Nobedder wrote:That 312-16 rod is fine, but you may find easier welding with 308lsi, especially on older (read used and abused) materials. There isn't an engineer on site who knows the alloy your welding on?

I would suspect a 300- series. 316 has a higher corrosion resistance than 304, particularly for salts and caustics. 308 will weld either, as will the 312-16 rod, but if no one at the plant can give you a "required" filler, the 308lsi will perform better for you, as the weldor. The "si" refers to silicon, same as the "S" in a carbon TIG wire like ER70S-6, and it provides scavenging for impurities in this "well used" parent metal.

When the weld is important, I only buy Lincoln brand... Tried many, and they are just more predictable and constant one rod to the next, one batch to the next. Also, Stainless stick-rod does not tolerate moisture at all (I've had the flux literally "explode" when damp). That's why they come in sealed metal cans. Keep 'em in a rod oven once opened.

Steve S

Great info, thanks. A far as an engineer, not really. A huge majority of the engineering money and effort is spent on product development and productions gains, and this particular "line" has been in place more or less since the early 50's - with several modifications over the years, so little engineering money is left to be spent in issues like this. The plant where I work is one of GM's foundries and our engineering staff is fairly "fluid" because they are often floating from plant to plant, so it's hard sometimes to deal with very specific issues like this one and to be honest it is more of a personal issue of aesthetics for me and a few others. The work orders come from stress cracking due to explosions in the quench tanks from steam pockets in the castings, not so much weld failures - per se. In our industry, as many other in manufacturing I'm sure, downtime is measured in minutes and thousands of dollars, so aesthetics isn't held in very high regard sometimes, not to say we don't take pride in our work- but sometimes you have to make it function till the next week end when a proper repair can be executed. I did some checking today, and 304 is the alloy, as it was felt that the stress of the process would fatigue the tank far faster than corrosion would. We generally only use Lincoln rod throughout the plant, although we do use Crown for our stainless, which is kept in rod ovens. I will check on getting some 308si rod for sure. Thanks again, Bobby.

Alexa wrote:http://www.esabna.com/EUWeb/FM_handbook/577fm3_2.htm

Nice link, thanks!

Bobby_dean75.

Those entities (Esab, Lincoln, Paton, Linde, Hobart, etc.) that invested heavily in electric arc welding in the early 1900's have accumulated a wealth of experience. They are quite generous in sharing it too.

Building yourself an archive of welding related links is helpful.
Almost all of our questioned have been addressed by these entities over the years.

Tanks.
Alexa

Repeated comment removed.