What Is SMAW Welding?

Quick Answer: SMAW (Shielded Metal Arc Welding), commonly called stick welding, uses a flux-coated consumable electrode to create the arc and deposit weld metal. The flux coating melts during welding to produce shielding gas and slag that protect the weld pool. SMAW remains the most versatile field welding process for piping construction due to its portability and tolerance to adverse conditions.

How SMAW Works

An electric arc forms between the tip of the coated electrode and the base metal. As the electrode melts, three things happen simultaneously: the core wire deposits filler metal, the flux coating generates a protective gas shield, and liquid slag covers the solidifying weld to prevent oxidation. After each pass, the welder must chip and wire-brush the slag before the next layer.

Parameter	Specification
AWS designation	SMAW (per AWS A3.0)
Common electrode (CS)	E6010 (root), E7018 (fill/cap)
Common electrode (SS)	E308L-16, E309L-16, E316L-16
Common electrode (Cr-Mo)	E8018-B2 (1Cr-0.5Mo), E9018-B3 (2.25Cr-1Mo)
Electrode diameter	2.5 to 5.0 mm (3/32” to 3/16”)
Current type	DC+ (E7018), DC+ or DC- (E6010), AC (E6013)
Deposition rate	0.5 to 3.0 kg/h (1.1 to 6.6 lb/h)
Positions	All positions
Wind tolerance	Good (flux generates its own shield)
Governing codes	ASME Section IX, AWS D1.1, API 1104

Electrode Classification (AWS A5.1 / A5.5)

The four-digit E-number system encodes essential information:

• E: Electrode
• First two digits: Minimum tensile strength in ksi (e.g., E70xx = 70 ksi)
• Third digit: Welding position (1 = all positions, 2 = flat and horizontal)
• Fourth digit: Flux type, current, and polarity

Electrode	Flux Type	Key Characteristic
E6010	Cellulosic (high hydrogen)	Deep penetration root pass; DC+ only
E6011	Cellulosic	Similar to E6010; AC or DC
E7018	Low hydrogen (iron powder)	Smooth fill/cap; low risk of hydrogen cracking
E7024	Iron powder	High deposition; flat and horizontal only
E8018-B2	Low hydrogen (Cr-Mo)	1.25Cr-0.5Mo for alloy piping

Common Mistake

E7018 low-hydrogen electrodes must be stored in heated holding ovens (120-150 C) after opening. Moisture pickup in the flux coating introduces hydrogen into the weld, increasing the risk of hydrogen-induced cracking; especially in thick-wall, high-strength piping.

Field Piping Applications

SMAW dominates field welding for oil and gas piping because:

• Equipment is portable and inexpensive (no gas bottles, no wire feeders)
• Wind and outdoor conditions have minimal effect on weld quality
• E6010 root passes on carbon steel pipe deliver reliable full-penetration joints
• Electrode changes are fast for position welding on fixed pipe joints

The standard field procedure for carbon steel pipe joints per API 1104 is: E6010 root pass, E6010 hot pass, E7018 fill and cap passes. The WPS and PQR document the qualified parameters.

All completed welds require non-destructive testing; typically radiographic or ultrasonic examination for butt welds on pressure piping.

Read the full guide to cast and forged steel making