GTAW · Low-alloy steel
ER90S-B3
The higher alloy chrome-moly torch rod, used on the piping grades that run hotter than the lower chromium class can handle, typically with preheat and heat treatment.
What the designation means
- ER
- Classified as both an electrode and a hand fed filler rod.
- 90
- 90,000 psi minimum tensile strength of the deposit.
- S
- Solid rod or wire.
- -B3
- A chromium-molybdenum chemistry class at nominally 2.25 percent chromium and 1 percent molybdenum.
At a glance
| Process | GTAW |
|---|---|
| Family | Low-alloy steel |
| Positions | All positions |
| Polarity | DCEN |
| Shielding | Welding grade argon at the torch, plus an inert back purge on pipe roots |
| Minimum tensile strength | 90 ksi |
Typical uses
- Root passes on 2.25 chromium 1 molybdenum high temperature piping
- Power plant headers and hot reheat lines
- Hydroprocessing reactor piping in refineries
How it runs
- Higher hardenability than the lower chromium class, so preheat is essential
- Clean, precise puddle suited to open root work
- Post weld heat treatment is normally required to reach specified properties
- Root must be fully purged to prevent oxide on the inside surface
Storage and handling
Store rods in the sealed tube in a dry area and keep them free of oil and rust; contamination shifts the alloy chemistry in the deposit.
Compare with
GTAWER80S-B2The chrome-moly torch rod used for root passes on lower alloy high temperature piping, matched to the same alloy class as the companion covered electrode.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.GMAWER70S-2The most heavily deoxidised of the common carbon steel wires, which is why it tolerates rust and mill scale and is the standard pick for open root passes.