A 7018 welding rod is a low-hydrogen stick (SMAW) electrode for carbon steel that deposits weld metal with at least 70,000 psi tensile strength. It is the standard rod for structural steel because its low-hydrogen coating gives tough, crack-resistant welds, as long as the rods are kept dry.
This guide explains what each part of the classification means, what 7018 is used for, the amperage range for each rod diameter, and how to store and redry the rods so the low-hydrogen property is not lost. Figures for a typical commercial 7018 come from Lincoln Electric’s published data for its Excalibur 7018 MR electrode; other brands publish their own data sheets, so check the box for the rod you actually have.
What E7018 Means
Carbon steel stick electrodes are classified under AWS A5.1/A5.1M:2025, Specification for Carbon Steel Electrodes for Shielded Metal Arc Welding (preview checked October 2026). Its scope covers classification of carbon steel electrodes for shielded metal arc welding of carbon steels, including weld metal chemistry, mechanical properties, usability and moisture tests for low-hydrogen coverings. The full name on a box is usually something like E7018 H4R.
- E stands for electrode.
- 70 is the minimum tensile strength of the deposited weld metal in ksi. Lincoln’s data sheet lists the AWS requirement as 70 ksi (490 MPa) minimum tensile and 58 ksi (400 MPa) minimum yield.
- 1 means the rod can be used in all positions: flat, horizontal, vertical and overhead.
- 8 describes the coating: a low-hydrogen covering with iron powder, which runs on AC or DC electrode positive.
- H4 means the weld deposit tests at no more than 4.0 mL of diffusible hydrogen per 100 g of weld metal.
- R means the covering has passed a moisture-resistance test, so it picks up water from the air more slowly.
What a 7018 Rod Is Used For
7018 is the general-purpose rod for structural and code work on carbon steel. Typical jobs include beam-to-column and moment connections, base plates, stiffeners, stair stringers, trailer frames and repairs on heavy equipment. Its weld metal strength matches the common building steels: A36 steel at 36 ksi minimum yield and ASTM A992 wide flange beams at 50 ksi minimum yield both sit below the 58 ksi minimum yield of E7018 weld metal.
Low hydrogen matters because hydrogen absorbed into a weld can cause cracking under or beside the bead hours after welding. Thick sections, restrained joints and higher-strength steels are most at risk. That is why structural welding procedures usually call for low-hydrogen electrodes such as 7018. Whether a particular joint needs preheat, a specific electrode or a qualified procedure is set by the project’s welding code and the engineer of record, not by the rod box.
7018 compared with other stick rods
Welders often contrast 7018 with the 6010 and 6011 rods used for root passes and dirty or rusty steel, and with 6013 for light sheet work. The 60-series rods have lower minimum tensile strength (60 ksi) and are not low-hydrogen. 7018 needs cleaner steel and a tighter arc, but gives smoother beads and tougher weld metal. If you are choosing between processes rather than rods, our guide to types of welding compares stick with the wire and tungsten processes.
7018 Amperage Chart by Rod Size
These are the typical operating ranges published for Lincoln Excalibur 7018 MR in its Excalibur 7018 MR product brochure, publication C2.10.10b (checked October 2026). DC+ (electrode positive) is the preferred polarity.
| Rod diameter | Length | DC+ amps | AC amps |
|---|---|---|---|
| 3/32 in (2.4 mm) | 14 in | 70 to 110 | 80 to 120 |
| 1/8 in (3.2 mm) | 14 in | 90 to 160 | 100 to 160 |
| 5/32 in (4.0 mm) | 14 in | 130 to 210 | 140 to 210 |
| 3/16 in (4.8 mm) | 14 in | 180 to 300 | 200 to 300 |
| 7/32 in (5.6 mm) | 18 in | 250 to 330 | 270 to 370 |
| 1/4 in (6.4 mm) | 18 in | 300 to 400 | 325 to 420 |
Start near the middle of the range and adjust. Vertical and overhead welds generally run at the lower end, flat fillets toward the upper end. The data sheet ranges are wide, so a short test bead on scrap of the same thickness is the quickest way to dial in.
Mechanical Properties of 7018 Weld Metal
The same Lincoln publication lists the AWS E7018 H4R requirements next to its own as-welded test results:
| Property | AWS E7018 H4R requirement | Lincoln test results, as-welded |
|---|---|---|
| Yield strength | 58 ksi (400 MPa) min | 62 to 74 ksi |
| Tensile strength | 70 ksi (490 MPa) min | 74 to 88 ksi |
| Elongation | 22% min | 25 to 37% |
| Charpy V-notch at -20°F (-29°C) | 20 ft·lbf (27 J) min | 89 to 246 ft·lbf |
| Diffusible hydrogen | 4.0 mL/100 g max | 2 to 3 mL/100 g |
Lincoln notes that test results come from welds made under prescribed test conditions and should not be assumed for a particular weldment. For design, use the AWS minimums, not a brand’s typical results. The related 7018-1 classification adds a toughness requirement at a lower temperature (Lincoln’s 7018-1 MR is tested at -50°F) for cold-service work.
How to Store and Redry 7018 Rods
A 7018 rod is only low-hydrogen while its coating is dry. Moisture in the coating puts hydrogen back into the weld. Lincoln’s Storing and Redrying Electrodes guide (checked October 2026) gives these rules:
- Unopened cans: hermetically sealed containers protect the rods well in good storage conditions.
- Opened cans: keep the rods in a holding cabinet (rod oven) at 250 to 300°F (120 to 150°C).
- Exposure time: standard EXX18 rods should be issued to welders twice per shift. Moisture-resistant (R suffix) types may be exposed for up to 9 hours. Codes may set different limits.
- Redrying: rods exposed to air for less than a week with no direct contact with water can be redried at 650 to 750°F (340 to 400°C) for one hour. Rods that got wet or sat in high humidity should first be pre-dried at 180 to 220°F (80 to 105°C) for 1 to 2 hours, then given the same final redry.
- Do it properly: spread the rods out in the oven so each one reaches temperature. Several hours at a lower temperature is not equivalent, and drying hotter is not allowed.
- When to throw them out: discard rods if repeated redrying makes the coating fragile, flaky or prone to breaking off, or if the arc behaves noticeably differently.
Signs of damp rods include porosity, rough beads, slag that is hard to remove and, in severe cases, cracking. Lincoln warns that moisture-related cracking risk is highest on base metal or weld metal above 80 ksi (550 MPa) yield strength.
Tips for Running 7018
- Clean the joint. Remove rust, paint, oil and heavy mill scale; 7018 is less tolerant of dirty steel than 6010 or 6011.
- Keep a short arc. A long arc lets air into the weld pool and causes porosity.
- Chip slag between passes. Clean every pass on multi-pass welds.
- Check coatings on the base metal. Welding over galvanizing needs fume control and joint preparation; see our guide on welding galvanized steel.
- Read the drawing. Size and length of each weld come from the weld symbols on the shop drawings. Structural welds should be made by a qualified welder to a procedure approved for the job, and the connection itself must be designed by a licensed structural engineer.
7018 Welding Rod FAQ
What amperage should I run a 1/8 inch 7018 rod at?
Lincoln lists 90 to 160 amps DC+ and 100 to 160 amps AC for its 1/8 inch Excalibur 7018 MR. Start near the middle and adjust for position and plate thickness.
Can you run 7018 on AC?
Yes. The 8 in the classification means the rod is designed for AC or DC electrode positive. DC+ is the preferred polarity in Lincoln’s data, and AC ranges are slightly higher.
What is the difference between 7018 and 6013?
7018 is a low-hydrogen rod with 70 ksi minimum tensile strength for structural work. 6013 has 60 ksi minimum tensile strength, is not low-hydrogen and is mainly used for light fabrication and sheet metal.
Do 7018 rods need to be kept in an oven?
Once the can is opened, yes for code work. Lincoln recommends a cabinet at 250 to 300°F and redrying at 650 to 750°F for one hour if rods have been exposed too long.
What does H4R mean on a 7018 box?
H4 means the weld deposit has no more than 4 mL of diffusible hydrogen per 100 g. R means the coating passed the moisture-resistance test, so it can stay out of the oven longer than a standard 7018.
Reference information only, not engineering advice. Disclaimer.