I got a box of 12018M rod given to me. What does the M mean ? Should they be used on ac or dc ? What would you use a rod with that much tensile strength on.

 

with that high of tensile strength, one guess might be its a cast iron rod. is this a stick rod or tig? im not sure, but could the M also be a manufacturers mark?

it should be most likely be run DC. im feeling lazy and dont want to go get my book, you may also be able to run it AC, but im sure of DC

 

Generally used for HY-100 steel, requires a special preheat and cooldown procedure or the weld will crack. DC, reverse polarity generally.
The M means military specs.

 

It's a 1/8" stick rod.

 

Interesting, considering where I got them.
The military has there own custom rods ? Is this a cast rod then ?

 

The last two digits indicate it's an all position low hydrogen electrode. Could be for mild steel but most likely for low alloy given the rated strength and comments made by Ford-Six. Definitely not a cast iron electrode.

 

12018M
120: 120,000 psi tensile, as welded, 1: all position, 8: flux composition, M: ?, milspec, maybe?
This is a Low Hydrogen electrode. It is used for higher strength steels. It is in the same family as 7018, 8018, 9018, 11018, with 7018 the most common.
Per Lincoln Electric:
<TABLE cellSpacing=1 cellPadding=1 width="100%" border=0><TBODY><TR><TD class=stepsearch_table_heading colSpan=6>Low Hydrogen, Low Alloy Steel Stick Electrodes</TD></TR><TR><TD class=series_table_content noWrap align=left width=0>Jet-LH 8018-B2 MR</TD><TD class=series_table_content align=middle width=0>E8018-B2 H4R</TD><TD class=series_table_content vAlign=center align=middle width=0>AC, DC+</TD><TD class=series_table_content_left_align width="90%">If your welding involves 1-1/4% chromium and 1/2% moly power pipe, tubes, boilers or castings, you’ll want Jet-LH 8018-B2 MR as your welding partner. It offers a nominal 1-1/4% chromium and 1/2% molybdenum deposit. Reach for this electrode when design temperatures exceed 850°F (450°C).


</TD></TR><TR><TD class=series_table_content_alt noWrap align=left width=0>Jetweld LH-90 MR</TD><TD class=series_table_content_alt align=middle width=0>E8018-B2 H4R, E9018-G H4R</TD><TD class=series_table_content_alt vAlign=center align=middle width=0>AC, DC+</TD><TD class=series_table_content_left_align_alt width="90%">LH-90 MR was designed to meet the rigorous demands of high temperature, high pressure piping assignments. This electrode offers a nominal 1-1/4% chromium and 1/2% molybdenum deposit and meets the requirements of high tensile (90,000 psi) steels.


</TD></TR><TR><TD class=series_table_content noWrap align=left width=0>Excalibur 8018-C1 MR</TD><TD class=series_table_content align=middle width=0>E8018-C1 H4R</TD><TD class=series_table_content vAlign=center align=middle width=0>AC, DC+</TD><TD class=series_table_content_left_align width="90%">Excalibur 8018-C1 MR is the ideal moisture resistant electrode for welding on equipment and pipe that transport liquid ammonia, propane and other gases. An excellent all-position electrode for applications requiring a nominal 2-1/4% nickel deposit.</TD></TR><TR><TD class=series_table_content_alt noWrap align=left width=0>Excalibur 8018-C3 MR</TD><TD class=series_table_content_alt align=middle width=0>E8018-C3 H4R</TD><TD class=series_table_content_alt vAlign=center align=middle width=0>AC, DC+</TD><TD class=series_table_content_left_align_alt width="90%">Excalibur 8018-C3 MR is a 1% nickel all position electrode for fabrication or repair of 1% nickel steels, as well as a wide variety of other low alloy and carbon steels.</TD></TR><TR><TD class=series_table_content noWrap align=left width=0>Jet-LH 9018-B3 MR</TD><TD class=series_table_content align=middle width=0>E9018-B3 H4R</TD><TD class=series_table_content vAlign=center align=middle width=0>AC, DC+</TD><TD class=series_table_content_left_align width="90%">Great low hydrogen stick electrode. For welding 2-1/4% chromium and 1% molybdenum steels when heat treating is required. Good mechanical properties in the as-welded and stress-relieved conditions. A great choice when temperatures exceed 850°F (450°C).


</TD></TR><TR><TD class=series_table_content_alt noWrap align=left width=0>Excalibur 9018M MR</TD><TD class=series_table_content_alt align=middle width=0>E9018-M H4R</TD><TD class=series_table_content_alt vAlign=center align=middle width=0>DC+</TD><TD class=series_table_content_left_align_alt width="90%">Excalibur 9018M MR is intended for welding high strength steels of 90,000 psi (620 MPa) tensile strength and higher.</TD></TR><TR><TD class=series_table_content_alt noWrap align=left width=0>Excalibur 11018M MR</TD><TD class=series_table_content_alt align=middle width=0>E11018M-H4R</TD><TD class=series_table_content_alt vAlign=center align=middle width=0>DC+</TD><TD class=series_table_content_left_align_alt width="90%">Excalibur® 11018M MR™ is designed primarily for joining high strength steel types in the as-welded or stress relieved conditions with excellent low temperature impact properties and robust welding procedures. All-position welding, except vertical down.</TD></TR></TBODY></TABLE>

 

It sounds like Nuclear Industry rod. Nice to have but overkill.

If that type of rod isn't kept sealed and in a welding rod oven, it tends to go stale fairly soon. Interestingly, in the Nuclear Reactor business, if some of the rod is exposed to the air for longer than eight hours, it is trashed and fresh stuff is brought out.

 

So, for the average person just fabricating things of mild steel, fixing rusted out things in his garage, this rod would be pretty much useless then ?

 

Not entirely. The deal about Lo-Hydrogen rod is that the mating surfaces need to be very clean. And, it is not "drag stick" rod like 6011 0r 6013. You really need to maintain the gap while welding. And your best luck might be on AC.

The more utility 6011/13 rod is better for dirty/rusty metal. While its never good to try to weld rust, those rods are better with less than optimum steels and welding conditions. Try it anyway.

 

Thanks....

 

http://www.blueshield.ca/Content/CMS...logue-SMAW.pdf

Blueshield simply lists it as " all position basic coating dc+/ ac"
"for welding steel with 120ksi tensile strength"

As long as they are still sealed and dry, try and see how well they burn.

For most applications in the home shop, your not that concerned with the tensile number on the rod anyway.

The only downside could be that the welds may be more brittle and unsuitable for things that need some flex or are subject to vibrations. You would probably never notice any difference for average projects, IMO.

 

Most low-hydrogen rods, even if they've been open a while, can be recovered by a good 'bake' in a rod oven.

 

Low hydrogen rods are the best rods you can use for fabrication. They the only rods used in structural welding applications. You will get a stronger weld then a conventional "wire welder". We also had flux core wire welding for in shop beam fabrication that produced a similar weld as a low hydrogen rod. They are a little more difficult to use but once you get used to them you will love them. I have burnt thousands of pounds of them in bridge construction when I was a certified welder.

 

with proper technique, and as long as they are kept dry. if your rolling your puddle over slag inclusion becomes a serious problem, very bad.

flux core is nice, love that penetration, its all about the penetration