Unweldable steels?

[lyuv]

Hi all,

I tried my first forge weld. Followed all guidlines I know of, the best I could, and failed miserably. Nothing stuck.

Before discussing the specifics of the proccess I used - I tried welding an O1 to an unknown mild steel, that was previously part of a gate. Are there such steels that resist forge welding? and rebars in particular?

[John McPherson]

Short answer: Yes, there are a LOT of steels out there that are totally unsuitable for welding, either by forge or conventional welding processes.

Longer answer: wrought iron from previous centuries was composed of nearly pure iron in bundles of long thread-like structures, with silica slag in-between. Pure iron welds back to itself readily, and the slag acted as a flux during the welding process. As long as you maintained cleanliness at a high enough temperature to keep the slag molten, it was easy.

ANYTHING ELSE ADDED, and the whole process needs tuning. The more carbon you add to steel, the harder it is to weld, and the temperature range changes as well. Other alloying elements like chromium, nickel, vanadium, molybdenum, etc. further skew the picture. You may need a more aggressive flux than borax, and that leads to fume toxicity problems.

Tramp elements that find their way in to re-melted scrap (and low-grade rebar is the potted meat of steel) interfere with grain structure formation, and will prevent a weld from taking, or cause it to crumble later. Copper, lead, sulfur, phosphorus will all cause problems in even trace amounts.

[SmoothBore]

1 hour ago, John McPherson said:

Tramp elements that find their way in to re-melted scrap ..... Copper, lead, sulfur, phosphorus will all cause problems in even trace amounts.

In a solid fuel forge, Lead or Copper contamination is an often-overlooked problem.

[jlpservicesinc]

Forge welding to learn on your own is a task and is also hit or miss..    Being involved in a one on one situation with a skilled forge welder will have you welding all sorts of stuff together in just an hour or so.. 

There are a lot of miss conceptions as well as a lot of misleading information out there.. Not that the information is meant to be misleading but it comes down to knowing the colors, what the metal should look like before and during the weld..  What clean, properly prepared scarf looks like..    The scarf is how you get the ends to tie in and become invisible.. 

if you want more information geared at getting to a successful forge weld go watch the " How to" video on chain making on my jlpservicesinc youtube channel ( nearly all the videos have forge welding in them, well maybe 5 or 7 of them)..  It's a great starter as you don't need to hold both pieces together which for someone starting out or even an experienced smith to get right each and every time..  Also making fireplace pokers are another great one as the rod is bent back on itself and again no reason to hold 2 pieces.. 

[ThomasPowers]

I have bought new Cold rolled mild steel at a store that did not want to forge weld---and I had been forge welding for over a decade at that time.

[lyuv]

Thanks guys. This is great. Being able to blame failure on bad resources is the best. Second only to having someone to accuse. That is, a not-lyuv someone.

I was that close to considering it was somehow ME, just because I have never done or witnessed it.

[ThomasPowers]

that too....

[Steve Sells]

my money is on being a new forge welder not the steels

[jlpservicesinc]

in my early days of forge welding I had some steels which I couldn't weld..   Few years later I picked back up that same material and it welded just fine.. 

I have found as my skill set has increased there are a lot more opportunities to apply them in situations i would have been stumbled or stumped by in the past.. 

[ThomasPowers]

I still remember my first billet weld; Jim Crowell doing a 1 on 2 class back in the early 1980's, I remember him yelling at me "Don't look at it HIT IT!"

Had a follow up some years later with Billy Merritt at the IBA conference watching him do forge welds at temps I would consider too cold to forge at.

Trying to learn it on your own has got to be the slowest and most frustrating method.

[Frosty]

Same story for gas forges. Used to be everybody "KNEW" you can't weld in a gas forge. An old not to be talked about associate told me in no uncertain terms it couldn't be done when I was bringing a join up to temp in my first T burner pipe forge. When I looked at him and asked, "You can't weld in a gas forge?" He repeated himself more loudly and sternly, he was the professional bladesmith and I was a hobbyist after all. 

I pulled the piece, set the weld and asked again, "YOU can't weld in a gas forge?" IN truth he couldn't get his 3 nozzle, gun burner Mankel to weld. . . For HIM. 

There is I don't know how many lifetimes worth of stuff I don't know how to do, so far I haven't run into many I couldn't learn to.

Frosty The Lucky.

[ThomasPowers]

out back of the mountain they solid phase weld steel and aluminium together.  Makes dandy transition pieces when switching from a steel hull to aluminum upper on boats. (Of course the booms rattle the windows from time to time...)

When I was visiting my house and shop last weekend I saw my first "I heart Explosives" bumper stickers. I wonder how  the Border Patrol would like it if I got one for my truck that drives to a few hundred feet of the border 5 days a week...