Welding 1" steel

[ToolSteel]

I'm fairly new to blacksmithing and an absolute beginner when it comes to oxy-acetylene welding. I've made some hardie tools and stakes for metalworking. I want to weld them to shanks made of 1" square steel. I have number 2, number 5 and number 7 welding tips. If I'm reading tip charts correctly, I'll need a number 15 tip to join pieces of 1" steel. Can this be right?

[Rich Hale]

If you preheat the metal to a dull red you can likely weld it with a smaller tip. O/A would not be my first choice unless it is all I had.

[ToolSteel]

It is. Thanks.

[pkrankow]

I would really consider a different means, such as forging the shank before making the tool, or making a somewhat close fit and brazing. A hardy will likely be plenty strong with a brazed shank, but you will have to do any heat treat prior to brazing, and cool the treated area to prevent the temper from being completely drawn. Heat treating after brazing will melt the brass out. (although heat treating a hot work tool provides limited benefit)

There are advantages to being good at welding with OA, so don't let me discourage you.

Phil

[Thomas Dean]

If "I'm fairly new to blacksmithing and an absolute beginner when it comes to oxy-acetylene welding." then you will have difficulty making this weld. I suggest that you take the part to be welded to your local high school and get the kids in the metal shop to weld the part for you. Make sure you bevel the shanks so when you gind the welds down to fit your hardie hole you don't grind all the weld off.

[Steve Sells]

Heat treating after brazing will melt the brass out. (although heat treating a hot work tool provides limited benefit)

Phil

that all depends on what steel one used, I do heat treat my H-13 hot cuts.

[pkrankow]

that all depends on what steel one used, I do heat treat my H-13 hot cuts.

Absolutely correct. How about I revise my statement that simple steels like 10xx, leaf or coil spring, 5160, 4140, in other words common scrap stream materials, will benefit only slightly from heat treating when used for hot work, because the temper will be deeply drawn.

Phi

[Timothy Miller]

You could pin the shank in the center then weld around the outside. Welding 1" with O/A is off the hook it can be done but I have never seen it done.

[John B]

Absolutely correct. How about I revise my statement that simple steels like 10xx, leaf or coil spring, 5160, 4140, in other words common scrap stream materials, will benefit only slightly from heat treating when used for hot work, because the temper will be deeply drawn.

Phi

What do you mean by "Deep drawn" ? Is this when making the tool, or using it?

Explain process and reasoning please for clarification

[pkrankow]

In this case, if brazed like my suggestion, the temper well be drawn deeply (or tempered to a high temperature) in both cases, making and use. Heat treat after brazing will not be possible as the brass will melt out before getting to critical temperature, unless the part is big enough to wrap the braze in a wet rag while the working end is in the fire (torch), which means the working end could have been wrapped prior to brazing to similar effect.

In a general case using the mentioned common scrap stream materials for hot work heat treating will provide some, but rather small benefit as because being in contact with hot steel in use will draw the temper. Temper is fully drawn on these materials about the time it shows the dullest of red color.

These common scrap stream materials (4140, 5160, 10xx) will also start becoming soft at about 700F, so they will not exhibit good hot hardness, meaning the tool should be kept cool to get the most out of it. There are some boilermaker articles on Google Books that provided this information in relation to boiler design and material choice (and I am not finding them easily).

Here is 5160. Hardness as quenched is HRC62, tempered to 1200F HRC26, normalized HRC27, annealed HRC13,

Phil

http://www.matweb.co...c873abd66e74764
http://www.matweb.co...31db406e9213247
http://www.matweb.co...f7ca26cc97898fb

What do you mean by "Deep drawn" ? Is this when making the tool, or using it?

Explain process and reasoning please for clarification

[nuge]

This should be well within the capabilities of your setup given proper prep, preheat and skill. Do you have anyone that can give you a lesson? Then it's all practice. Oxy fuel welding is awesome, but slow. The upside is that if you can weld with gas the electric processes come easy.

[John B]

Thanks Phil for that technical explanation, and the book references which are great if you have industrial type equipment and facilities

If you annealed/normalised the bits before brazing, then allow to cool slowly after brazing you could still heat treat the working end of the tool.

You don't have to harden the complete tool, you can just harden the working edge/end, and you don't need to temper it.

In use whether cutting or punching, you keep the working end below the red heat when normalising starts to take place, so it will usually be harder/tougher than the workpiece being worked.

And if you do take the tool up above the lower critical point (your red heat?) and then quench, As I understand it, technically you are rehardening it again ?

Tempering reduces the brittleness and "chipability" and is not really necessary in these punching/cutting situations when you only H & T the working ends and not the complete tool

[Blacksmith Johnny]

The cost of a new tip the rite size for your torch plus the amount of gas you will burn are going to make those parts pretty exspensive. I would see if your local high school offers a night class , I know some do. Heck if you lived close buy you could weldem up in my shop. Good luck on what ever you decide.

[evfreek]

Do you have large enough tanks? Most newbies to OA welding are not familiar with the 1/7th rule. Be sure to pay attention to it. I am not really a big fan of OA welding and I have an oxypropane set, which doesn't weld. I visited my art buddy's workshop and he handed me a torch and told me to get to work on his T-Rex wireframe for a sculpture. It was great, almost like TIG but without the foot pedal or current control. There's no way I could do that with my stick welder. But heavy stuff is different.

For some odd reason, people who ask these sorts of newbie resource-limited questions are often kind of cheap. Not saying that you are, but as soon as you lease that big tank and try out that huge tip, you might be clutching your pockets like a penguin. Been there, done that. But, then again, I have a buddy who does all his big welding with a torch, and his gas budget is huge. Gone thru a bunch of stick welders in tank refills, and he loves the big tips and rosebuds. And, this guy is anything but cheap, being generous to a fault. But, somehow, I smell il pinguino waddling around, so watch your costs!

[ToolSteel]

Thanks for all the comments. Maybe I should clarify a point or two. Because it's so heavy and steady, I'll use the hardie hole on my anvil from time to time but I probably shouldn't have called these items hardie tools. That implies cutting and shaping red hot steel and that's not what I plan to do.
I'm trying to make raising stakes and forms on which to shape and planish copper. Some of these pieces will be 12"-24" long. I'm using 1.5" and 1.75" steel rods as my source material and roughing out the general shapes with an angle grinder. I have 1" square rod I'll be using for the shanks. Since these forms won't be heavily stressed and since nothing catastrophic will happen if they snap, I may consider brazing, but I'll definitely try to weld them first. I can easily put both form and shank into a forge and quickly bring them up to bright orange... if that will help me weld.
Now for the high school thing. There's an obvious benefit to watching and learning from others, but it makes absolutely no sense to have someone else do this for me. Making things myself and learning as I go is the whole reason I became interested in blacksmithing and metal working. Anyway, I hope to find time in the next few days to work on these items. Success or failure, I'll let you know what happens.

[Blacksmith Johnny]

Sorry if I was unclear. I tottaly agree with learning to do it your self , what i was reffering to is our local trade school offered a night class for adults to learn how to weld. the best part is they let you work on your own projects. A couple guys in the local car club did it. .Kill two birds with one stone

[ToolSteel]

Boy did THAT suck!
I don't know how many welding mistakes it's possible to make, but I made a lot of them. First off, I don't think I was using nearly enough acetylene and oxygen. I used a #5 tip and set both gasses to 5 psig, but I now realize I never cranked either gas as far as it would go. I managed to melt the edges of both pieces of steel but I don't think the heat penetrated very far. I believe I used an R45 (?) filler rod but I just sort of "buttered" the rod around the weld area without making sure it mixed well with the steel.
When the pieces were cool, I put each one in a vise and gave it a solid whack with a 3 pound hammer. I knew from the thudding sound that things weren't right. When I took the pieces apart, there was no melting and intermingling of metals whatsoever.
I'll probably try it again, but more aggressively.
I'll also give brazing a try.
Even though the final result was bad, I managed to learn a lot of things NOT to do next time. This is generally how I figure out my projects.
Thanks for the input.

ToolSteel

[John McPherson]

Okay, now that you have tried it your way, I will put in my two cents. For what it's worth, I teach this (Oxy-Acetylene Welding) and other classes at a community college.

One inch is HUGE for OA, it is much better suited for sheet metal unless you have a big, professional sized rig and tanks. You had the right tip and settings for 1/4" stock. And you may be able to get that combination to work with some assistance. I would suggest working on some smaller stock before diving into this as your first attempt at OAW.

You needed a #10 tip and about 9psi on both gases. The rule of thumb to judge adequate tip size/gas flow is to hold the torch on the base metal until a puddle forms. Count the seconds: one mississippi, two mississippi, etc. You will see it melt, it will look like butter on a biscuit (or scone if you prefer), glossy with a little scale floating on the surface. If you can not get a puddle with good technique within 10-12 seconds, you do NOT have enough BTU's to get the job done. 5-6 seconds would be ideal, 2-3 is excess heat and hard to control on small stock.

Now for the assistance. This is not cheating, these are basic industry standard practices for all welding. V out the metal on both sides to be joined, grind clean. Tack welding with a MIG to hold the parts in place is fine. Preheat both pieces to 300 to 500F, hotter is better. (Yes, this means more personal protective gear and care to prevent burns. Goes with the territory, deal with it, or move on.) Lay it down flat on a flame-proof surface, brick or steel, no concrete! Wire brush the surfaces clean just before you start.

Light your torch, adjust to a neutral flame, angle it about 75 degrees into the direction of travel, hold the inner cone about 1/4" above the surface, and move it in a circle over a dime sized area until the puddle forms. Pull the torch back about a half inch, keeping the outer envelope of flame over the puddle. This prevents oxygen from contaminating the puddle, acting in place of a flux. Feed the rod into the puddle, in the front third of the direction that you want the bead to form. The rod should melt off like stirring coffee with a chocolate straw, cooling the puddle and building up a bead. Pull the rod back slightly (1/2") into the outer flame, not up into the atmosphere. The tip should remain red hot. Do not attempt to drip it onto the base metal, that accomplishes nothing. Move the flame cone back over the forward edge of the puddle, with the filler rod ready, and repeat the dance. Small hand movements, like knitting. Heat the puddle, feed the puddle, over and over. Once you get the hang of it, it is like hammer and tongs, or knife and fork, hands working together.

Flip it over, and do a bead on the other side to equalize the weld stresses. Grind or power wire brush down to clean metal between passes. Scale left on the surface leads to foaming, popping and contamination of the puddle. Weld, flip, weld, flip until the build-up is sufficient.

Amended to add warnings: If you dip the tip of the inner flame cone of unburned gas into the puddle, you WILL get an explosion, and a shower of molten metal. Proper PPE is a must, full body covered and tinted safety glasses is a minimum level. A full face shield and leather welders cape/sleeves is recommended at this heat level.

[clinton]

Excellent how- to John. Our local junior college has a braze weld test that uses 1/2 inch square stock, the ends are beveled at 45 degree angle leaving a small land at the point. Once the weld is complete and allowed to cool it is put to a 360 degree twist test. It can be done, it takes most students 2 or 3 times to get right. I still have my test coupon from 1986

[ToolSteel]

John, I am simply amazed. Your explanation was clear and vivid. You've answered questions I didn't even know enough to ask.
I'll practice on smaller stock until I can locate a #10 tip.
Thanks.
ToolSteel

[John McPherson]

You may be able to do this with the #5 if you follow the steps above. Each bead of weld will be 1/8" or so thick. See if you can build up 1/2" of beads on a thinner plate, say 4 x 4 x 1/4". Once you can do that, you are ready to rock.

Once you start putting heat into the system, don't stop unless it turns red, then wait until it is back to black. The localized heat will make it easier to add the next bead, like building with rows of bricks.

You really need a fire watch while you are doing this, it is easy to get lost in the work. They just need to keep you from setting yourself on fire, and pay attention to the regulator pressure readings. It is easy to overdraw acetylene from one tank with a big tip, multi-tank manifolds are required for big work.