What's new
What's new

easiest weld:4140 or 8620?

Sea Farmer

Diamond
Joined
Mar 25, 2006
Location
Cape Cod, Massachusetts
I want to make some blacksmithing tools, nail headers. Have diligently searched the books, online, etc. and settled on these two alloys as having suitable characteristics for the header: 4140 or 8620. I know some sources suggest other alloys, but these are the most available to me.

Although I'm certainly open to suggestions of others?

My design calls for me to make the header out of 1.25" round, about 1/4" thick, then welded to a short mild steel handle. Stick welder. Shouldn't be much stress on the weld.

Literature says 8620 welds easier. True? 6011 or 7024 sticks work ok for this?

For the curious, the nail header is made by doming the end of a rod of the alloy steel with a grinder or on a lathe, then slicing off a 1/4" (approx) section, and drilling/drifting a square hole in the center. The hole is not straight through but has an "hourglass" sort of profile, to help extract the nail, and is polished with a bit of sandpaper on the inside. The hot stock is formed to have a bulge at one end (upset), dropped through, and the header holds it while you strike a few blows to form the nail's head. Hopefully, the nail comes out easily:)
 
welding 8620/4140

I have made some "smith'n" tools myself. Most of the high quality "store bought" tools for the pro's are made from 4140. The top $ production tools are made from H13 or S7 tool steel.
Of the two steels you mentioned, the 8620 is more weldable[less carbon& alloys] than the 4140. If you only have the choice of E6011 & E7024 rod...the 7024 will weld medium carbon steels with less chance for cracking than 6011, but 7024 is a flat position only rod that may give you trouble going around a handle.
I actually have an electrode [weldmold #920] that is made exclusively for 8620 steels. It is a low hydrogen rod very similar to E9018.
I would recommend a low hydrogen rod for 8620 or 4140 for max. quality[min E7018 AC type for small shop welders].
If you must use 6011/7024 [you may have a small AC stick welder] give it a try[weld while still hot from forging, and give the weld a little hammer test after cooling, to be sure it will hold up for service.
 
You are thinking like a machinist, (find the shape and cut), not a blacksmith.

I would start with something like an old (rock) drill stem, or heavy truck tie-rod form the scrap yard, something with the section required to make the header die, then draw out the end for a tang.

The drill steel will be a shock steel unless very old, and the tie-rod will be 1045 or maybe even 4130
 








 
Back
Top