it is alloy steel. The composition can vary and someone who works with it every day might know the alloy number. My guess is a chrome moly. At the least you should use E 7018 or E 8018 if you are seeking full strength welds. If you are using 6011 and 7014 you are not using low hydrogen electrodes. The workaround for this is to preheat before welding so that the material cools more slowly allowing the hydrogen to migrate out of the joint. A good test for these situations is to weld a small plate to the unknown alloy with a fillet weld about one to two inches long. Snap the plate off and inspect the weld. If the weld bead tears out of the unknown alloy it is brittle and you need preheat. Repeat the exercise with increasing preheat until you get no tear out of the alloy metal.
If you don't preheat with these alloys you run the risk of a brittle fracture. Often you get underbead cracking which you will not see until a sudden failure.

 

I thought 7014 was good for low alloy?
7014 Mild Steel Electrodes
Description: Mild Steel Electrodes

An all position electrode for mild and low alloy steels with an iron powder covering. The iron powder yields a high deposition rate. The welds reflect smooth beads with fine ripples. It is particularly advantageous when poor fit-up exists. The slag is easily removed, often self-lifting.

Typical Application: Heavy sheet metal, frames, shelving, general maintenance and fabrication

 

There's no 2.375" drill pipe. At best, we use p-110 grade for milling projects and work strings that are too heavy for standard wall tubing. The main thing that changes is the connection type. Only the higher end premium pipe used for special applications have chrome content. You can run 60 or 70 series rods with no issues. Most run 6010, 6011, or 7018. Most 2.375" oilfield tubing is j-55 to n,l-80 grade. No special rods needed.

 

There's no 2.375" drill pipe. At best, we use p-110 grade for milling projects and work strings that are too heavy for standard wall tubing. The main thing that changes is the connection type. Only the higher end premium pipe used for special applications have chrome content. You can run 60 or 70 series rods with no issues. Most run 6010, 6011, or 7018. Most 2.375" oilfield tubing is j-55 to n,l-80 grade. No special rods needed.

Thanks! Could you elaborate on the there is no such thing as 2.375 pipe. I see a lot of 2 3/8 Mathew Jr listed from well selling suppliers. suppliers.

 

As stated earlier different grades from j-55 to p-110 different alloys non of it is drill pipe per say it is production tubing or work strings the two most common weights are 4.70 per ft or 5.95 per foot biggest difference is type of thread , the 4.70 usually has a coupling on it with upset ends { eue } external upset ends and the other has a taper thread too many types to mention these usually when the threads get bad they remachine the ends till the upset gets to short to machine or the tube gets worn out. All of it is weldable some of it has been in some h2s which takes its toll on wall thickness. Low hydrogen is always your best bet on used tubing

 

I built my garage supports and some supports in my home with drill stem. I was told by my union iron worker neighbor to always use 7018.... so I did. Nothing has broken yet...

 

2 3/8 or 2 7/8 & 3 1/2 tubing are measured od unlike pipe because it is under octg { oil country tubular goods } and like all casing it is refered to by outside diameter and weight per ft versus nominal pipe size and schedules
2 3/8 4.7# L-80 versus 2" sch 40 grade B and so forth

 

There is no 2.375" drill pipe. There's plenty of 2.375 tubing. Just not used for drilling.

 

Normally 7018 is used but it shouldn't be used for anything structural or under high load that could have serious consequences if it breaks. For fencing, pens and other non heavy duty projects it is fine.

 

Guy at works said he used to wed it with 6010 or 6013 no problems. I just kinda wonder long term how it holds up vs a 7018 weld?

I think the ductability of 7018 would be the best bet. Seems I have seen some old pipe fences welds fail for some reason or another bad weld, bad prep, or wrong rod who knows. My electrode chart shows 7014 is also fairly ductile.

 

I built an arena and several cattle pens with my dad back when I was still in junior high and high school with 6011 and 6010 and they are just fine. I'm 30 now. Only time I've used 7018 for this tubing is when it is heavily magnetized. They seem to work better for me. However, I have welded it with 6013 and have found cracks in the weld once it cooled off. Hope that helps.

 

Yes thanks for sharing your real word experience.