Australian Weld Inspection — AS 1554 Methods Guide
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Reference for weld inspection methods per AS 1554 series (AS/NZS 1554.1 for structural steel). Covers visual inspection, NDT methods, acceptance criteria, and inspection frequency for welds in AS 4100 construction.
Inspection Levels per AS/NZS 1554.1
| Level | Weld Category | Inspection | NDT Required |
|---|---|---|---|
| 1 | General fabrication | Visual only | None |
| 2 | Structural (SP category) | Visual + selected NDT | UT on 10% of full-pen butt welds |
| 3 | Critical (GP category) | Visual + comprehensive NDT | UT 100%, MPI on fillet welds |
Visual inspection — 100% of all welds, minimum requirement per AS 1554.1 Clause 6.
NDT Methods
| Method | Application | Detectable Defects | Cost |
|---|---|---|---|
| Visual (VT) | All welds, 100% | Surface cracks, undercut, profile | Very low |
| Ultrasonic (UT) | Butt welds ≥8 mm thick | Subsurface cracks, lack of fusion, slag | Medium |
| Magnetic particle (MPI) | Ferritic steel surfaces | Surface/near-surface cracks | Low-Medium |
| Dye penetrant (PT) | Non-ferrous, all surfaces | Surface cracks, pinholes | Low |
| Radiography (RT) | Butt welds, critical | Volumetric defects (slag, porosity) | High |
Acceptance Criteria — AS/NZS 1554.1 Table 6.3
| Defect Type | SP Category | GP Category |
|---|---|---|
| Crack | Not permitted | Not permitted |
| Undercut depth | ≤ 0.5 mm | ≤ 1.0 mm |
| Lack of fusion | Not permitted | Not permitted |
| Slag inclusion | ≤ 3 mm (max 6 mm cumulative) | ≤ 6 mm (max 12 mm cumulative) |
| Porosity (single) | ≤ 3 mm diam. | ≤ 6 mm diam. |
| Porosity (cluster) | ≤ 5% of projected area | ≤ 10% of projected area |
| Reinforcement height | ≤ 2.5 mm | ≤ 3.5 mm |
| Convexity (fillet) | ≤ 1.5 mm | ≤ 3.0 mm |
Inspection Frequency — AS/NZS 1554.1 Table 6.5
| Weld Category | Visual | UT | MPI |
|---|---|---|---|
| GP (full pen butt) | 100% | 100% | As specified |
| GP (fillet) | 100% | — | 20% sample |
| SP (full pen butt) | 100% | 10% | — |
| SP (fillet) | 100% | — | — |
| General fabrication | 100% | — | — |
Design Resources
- [[Australian Steel Grades|/reference/australian-steel-grades/]] | [[Australian Steel Properties|/reference/australian-steel-properties/]] | [[Australian Beam Sizes|/reference/au-beam-sizes/]] | [[Australian Bolt Capacity|/reference/australian-bolt-capacity/]] | [[AS 4100 Beam Design|/reference/as4100-beam-design-example/]] | [[All Australian References|/reference/]]
FAQ
What is the minimum weld inspection per AS 1554? 100% visual inspection of all welds per AS/NZS 1554.1 Clause 6. NDT frequency depends on weld category (SP or GP).
When is ultrasonic testing required? GP category full-penetration butt welds require 100% UT. SP category butt welds require 10% UT. Fillet welds require MPI at 20% for GP category.
Are cracks permitted in structural welds? No. Cracks of any size are not permitted in any weld category per AS/NZS 1554.1 Table 6.3. Any cracked weld must be repaired.
Educational Use Only — This reference is for educational and preliminary design purposes only. All structural designs must be independently verified by a licensed Professional Engineer (PE) or Structural Engineer (SE) in accordance with AS 4100:2020 and all applicable Australian Standards. Results are not for construction.