Is SMAW on A36 with E7018 prequalified under AWS D1.1?

Yes, in most configurations. A36 is Group I per Table 6.9. E7018 (A5.1) is matched per Table 5.4. As long as the joint geometry is from Annex B and preheat meets Table 5.8 minimums, the WPS is prequalified per Clause 5.

What electrode diameter is typical?

1/8 in (3.2 mm) is the most common diameter for shop work in the flat and horizontal positions. 5/32 in (4.0 mm) for thicker passes; 3/32 in (2.4 mm) for thin plate or root passes in restricted positions.

What preheat does A36 need?

For A36 (Group I) up to 3/4 in thick with low-hydrogen E7018 (H4 or H8 designator), Table 5.8 typically allows preheat as low as 32°F [0°C]. Above 3/4 in, preheat rises. Above 1-1/2 in, preheat is typically 150°F [65°C] or higher.

SMAW WPS for ASTM A36: a complete walkthrough

The most common WPS in any structural fab shop: SMAW with E7018 on ASTM A36. Here's the full parameter set, what's prequalified, and the pitfalls.

The SMAW WPS for E7018 on ASTM A36 is the workhorse of structural welding. Every fab shop has one. Here is what a complete, audit-clean version looks like under AWS D1.1:2025.

Identification block

WPS number: WPS-25-001
Revision: 0
Date: 2026-05-08
Code: AWS D1.1/D1.1M:2025
Scope: SMAW production welds on ASTM A36, Group I, thickness 1/8 in to 3/4 in, in 1G / 2G / 1F / 2F positions
Status: Prequalified per AWS D1.1:2025 Clause 5

Process and joint

Process: SMAW (Shielded Metal Arc Welding), manual
Joint detail: B-U2 prequalified groove from Annex B (V-groove with backing), or B-L1 (V-groove with backgouging)
Joint sketch: embedded as figure 1

Base metal

Specification: ASTM A36
Group number: I (per Table 6.9 in 2025)
Thickness range: 1/8 in (3.2 mm) to 3/4 in (19 mm)
Diameter range: N/A (plate)

Filler metal

AWS classification: A5.1 E7018
Hydrogen designator: H4 or H8
Diameter range: 3/32 in, 1/8 in, 5/32 in
Storage: rod oven at 250°F [120°C] minimum after seal break; max 4-hour exposure before redrying

The hydrogen designator is essential — many audit findings cite WPSs that list "E7018" without H4/H8.

Position

1G, 2G groove (flat, horizontal)
1F, 2F fillet (flat, horizontal)
Progression: N/A (flat and horizontal only)

Electrical

Current: DC
Polarity: DCEP (Direct Current Electrode Positive, reverse polarity)
Amperage range:
- 3/32 in electrode: 70–110 A
- 1/8 in electrode: 105–145 A
- 5/32 in electrode: 140–190 A
Travel speed range: 4–8 ipm (depends on bead and position)
Arc voltage: 22–28 V (typical for E7018; not directly set by welder on SMAW)

Preheat and interpass

Minimum preheat: 32°F [0°C] for thickness ≤ 3/4 in with H4 filler (per Table 5.8)
Maximum interpass: 500°F [260°C] (typical for non-CVN structural work; CVN-required work is tighter via Table 6.8)
Method of measurement: temperature-indicating crayon, calibrated; measure 3 in [75 mm] from joint centerline before striking arc

Technique

Bead style: stringer beads preferred; weave beads acceptable up to 3× electrode diameter
Cleaning: slag chipped + wire brushed between passes; visible slag inclusions ground out before next pass
Peening: intermediate passes may be peened to relieve stress; root and cap passes not peened
Electrode angle: 5–15° drag for flat, 0–10° push for horizontal

Joint preparation

Cleaning: mill scale removed within 1 in [25 mm] of weld; rust, oil, paint removed within same band
Fit-up: root opening per joint sketch ± 1/16 in [1.6 mm]
Tack welds: maximum 1-1/2 in [38 mm] long at 8 in [200 mm] spacing; tack welds inside the joint groove fully melted into the root pass

Signature

Prepared by: [name], [credential], [date]
Approved by: [CWI name], CWI #[number], [date]

Common pitfalls on this WPS

Missing hydrogen designator — listing "E7018" without H4 or H8. Auditor flag.
Preheat listed for room temperature without method specified — incomplete.
Single amperage value instead of range — most common across all SMAW WPSs.
Joint sketch missing or referenced by label without embedding — auditor flag.
Storage rules omitted — particularly important for low-hydrogen electrodes; humidity can defeat the H-designator.

A rule engine that cross-references Table 6.9 (A36 → Group I), Table 5.4 (Group I → E7018 match), Table 5.8 (preheat by thickness × hydrogen), and Annex B (B-U2 / B-L1 joint geometry) catches all five at draft time.