SMAW · Low-alloy steel
E7018-A1
The entry point into the creep-resisting low-alloy family, adding molybdenum to a familiar low-hydrogen rod so the joint keeps its strength in hot service.
What the designation means
Point at any character to see what it claims. The classification is a sentence written in fields, not a product name.
- EElectrode for shielded metal arc welding.
- 7070,000 psi minimum tensile strength of the deposited weld metal.
- 1All welding positions.
- 8Low-hydrogen potassium covering with iron powder, run on direct current electrode positive or alternating current.
- -A1A carbon-molybdenum deposit, nominally about half a percent molybdenum, added for strength retention at elevated temperature.
At a glance
- Process
- SMAW
- Family
- Low-alloy steel
- Positions
- All positions
- Polarity
- DCEP, or AC
- Shielding
- Self-shielded by the covering
- Minimum tensile
- 70ksi
Typical uses
- Carbon-molybdenum piping and headers in elevated temperature service
- Boiler and steam plant components matching a C-Mo base metal
- Repairs on existing molybdenum-alloyed pressure piping
How it runs
- Handles like a standard low-hydrogen rod with a slightly stiffer puddle
- Deposit chemistry is molybdenum bearing for creep resistance
- Dense slag that releases as a shell
- Usually welded with preheat and interpass control set by the procedure
Storage and handling
Low-hydrogen storage rules apply, and alloy rods are less forgiving of moisture pickup: hermetic packaging until use, then a heated rod oven.
Compare with
SMAWE8018-B2A chrome-moly low-hydrogen rod for the lower alloy grades of high temperature piping, where chromium and molybdenum together resist creep and oxidation.SMAWE9018-B3The next step up in the chrome-moly family, carrying roughly twice the chromium of the lower class for higher temperature and higher pressure piping.SMAWE7018The workhorse structural low-hydrogen rod, giving a smooth arc, a moisture-controlled deposit, and the crack resistance that heavy sections and restrained joints demand.