Quick Answer
Quick Answer
AS/NZS 3679.1 covers hot-rolled structural steel bars, flats, and open sections (UB, UC, PFC, EA, UA) in grades 300 and 350. Grade 350 delivers a minimum yield strength of 360 MPa for flanges ≤ 17 mm and 340 MPa for flanges > 17 mm, with 480 MPa minimum tensile strength.
AS/NZS 3679.1 is the Australian and New Zealand standard for hot-rolled bars, flats, and structural sections (open sections). It applies to the full range of steel sections used in building and civil construction, including Universal Beams (UB), Universal Columns (UC), Parallel Flange Channels (PFC), Equal Angles (EA), Unequal Angles (UA), and flat bars. The standard is complementary to AS/NZS 3678 (plates) and AS/NZS 3679.2 (welded I-sections), together forming the core Australian structural steel material standards suite.
Scope and Applicability
AS/NZS 3679.1 applies to:
- Hot-rolled open sections: UB, UC, PFC, EA, UA
- Flat bars and round bars for structural use
- Products supplied in the as-rolled condition
- Grades 300 and 350 (and L0/L15 sub-grades for Charpy testing)
The standard does not cover:
- Welded sections (covered by AS/NZS 3679.2)
- Cold-formed hollow sections (covered by AS/NZS 1163)
- Reinforcing steel bars (covered by AS/NZS 4671)
All section sizes available in Australia and New Zealand are listed in the OneSteel (now InfraBuild) and BlueScope published section tables, which reference AS/NZS 3679.1 as the governing material standard.
Grade Coverage
| Grade | Sub-grades | Impact Requirement | Typical Use |
|---|---|---|---|
| 300 | (none), L0, L15 | None (base), 27 J @ 0 °C (L0), 27 J @ −15 °C (L15) | General structural frames, beams, columns |
| 350 | (none), L0, L15 | None (base), 27 J @ 0 °C (L0), 27 J @ −15 °C (L15) | High-load structural, bridges, crane rails |
When no L sub-grade is specified, Charpy impact testing is not required. L0 and L15 sub-grades carry identical chemical and tensile requirements to the base grade but include mandatory Charpy testing at the respective temperature.
Chemical Composition Requirements
All values are wt% maximum unless a range is shown. Ladle analysis applies.
Grade 300
| Element | Flange/Web ≤ 17 mm | Flange/Web > 17 mm |
|---|---|---|
| C max | 0.22 | 0.22 |
| Mn max | 1.70 | 1.70 |
| Si max | 0.50 | 0.50 |
| P max | 0.040 | 0.040 |
| S max | 0.040 | 0.040 |
| CEV max | 0.46 | 0.46 |
Grade 350
| Element | Flange/Web ≤ 17 mm | Flange/Web > 17 mm |
|---|---|---|
| C max | 0.20 | 0.20 |
| Mn max | 1.70 | 1.70 |
| Si max | 0.50 | 0.50 |
| P max | 0.040 | 0.040 |
| S max | 0.040 | 0.040 |
| CEV max | 0.48 | 0.50 |
CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15. For both grades, Al ≥ 0.015% is required when fine-grain (killed) steel practice is employed. Niobium (Nb) and vanadium (V) may be added as microalloying elements to achieve the required properties.
Mechanical Properties
Tensile tests per AS 1391. Test specimens are taken from the flange of sections or from the body of flat bars. For sections with flanges, the governing thickness is the flange thickness.
Grade 300
| Flange Thickness (mm) | ReH min (MPa) | Rm min (MPa) | Elongation A5 min % |
|---|---|---|---|
| ≤ 11 | 320 | 440 | 22 |
| > 11 to 17 | 310 | 430 | 22 |
| > 17 to 40 | 300 | 430 | 22 |
| > 40 | 280 | 410 | 22 |
Grade 350
| Flange Thickness (mm) | ReH min (MPa) | Rm min (MPa) | Elongation A5 min % |
|---|---|---|---|
| ≤ 11 | 380 | 480 | 22 |
| > 11 to 17 | 360 | 480 | 22 |
| > 17 to 40 | 340 | 480 | 22 |
| > 40 | 330 | 460 | 22 |
Impact Test Requirements
Charpy V-notch tests per AS 1544.2 are only required when L0 or L15 is specified.
| Grade | Sub-grade | Test Temperature | Average Minimum | Individual Minimum |
|---|---|---|---|---|
| 300 | L0 | 0 °C | 27 J | 20 J |
| 300 | L15 | −15 °C | 27 J | 20 J |
| 350 | L0 | 0 °C | 27 J | 20 J |
| 350 | L15 | −15 °C | 27 J | 20 J |
Three specimens per test. Average of three must meet 27 J minimum; no more than one specimen may fall below 20 J.
Mass and Dimensional Tolerances
Dimensional tolerances for sections are specified in AS/NZS 3679.1. Key tolerances:
| Parameter | Tolerance |
|---|---|
| Depth of UB/UC | ±2.5 mm or ±1%, whichever is greater |
| Flange width | ±3 mm |
| Flange thickness | −5% to +12% |
| Web thickness | −5% to +12% |
| Mass per metre | ±2.5% on individual length; ±1% on lots ≥ 10 t |
| Straightness | 1 mm per metre, 4 mm total in 6 m |
| Squareness of flange | 1% of flange width |
Key Section Properties — Universal Beams (UB), Grade 350
The following table lists principal UB sections rolled to AS/NZS 3679.1. Properties are calculated per AS/NZS 3679.1 and AISC section tables.
| Designation | d (mm) | bf (mm) | tf (mm) | tw (mm) | Mass (kg/m) |
|---|---|---|---|---|---|
| 150 UB 14.0 | 150 | 75 | 7.0 | 5.0 | 14.0 |
| 180 UB 16.1 | 173 | 90 | 8.0 | 5.0 | 16.1 |
| 200 UB 18.2 | 198 | 99 | 7.0 | 4.5 | 18.2 |
| 200 UB 22.3 | 202 | 133 | 7.0 | 5.0 | 22.3 |
| 250 UB 25.7 | 248 | 124 | 8.0 | 5.0 | 25.7 |
| 250 UB 31.4 | 252 | 146 | 8.6 | 6.1 | 31.4 |
| 310 UB 32.0 | 298 | 149 | 8.0 | 5.5 | 32.0 |
| 310 UB 40.4 | 304 | 165 | 9.7 | 6.1 | 40.4 |
| 310 UB 46.2 | 307 | 166 | 11.8 | 6.7 | 46.2 |
| 360 UB 44.7 | 352 | 171 | 9.7 | 6.9 | 44.7 |
| 360 UB 50.7 | 356 | 172 | 11.5 | 7.3 | 50.7 |
| 360 UB 56.7 | 359 | 172 | 13.0 | 8.0 | 56.7 |
| 410 UB 53.7 | 403 | 178 | 10.9 | 7.6 | 53.7 |
| 410 UB 59.7 | 406 | 178 | 12.8 | 7.8 | 59.7 |
| 460 UB 67.1 | 454 | 190 | 12.7 | 8.5 | 67.1 |
| 460 UB 74.6 | 457 | 190 | 14.5 | 9.0 | 74.6 |
| 460 UB 82.1 | 460 | 191 | 16.0 | 9.9 | 82.1 |
| 530 UB 82.0 | 525 | 209 | 13.2 | 8.0 | 82.0 |
| 530 UB 92.4 | 528 | 209 | 15.6 | 8.8 | 92.4 |
| 610 UB 101 | 602 | 228 | 14.8 | 10.6 | 101 |
| 610 UB 125 | 612 | 229 | 19.6 | 11.9 | 125 |
d = depth, bf = flange width, tf = flange thickness, tw = web thickness.
Key Section Properties — Universal Columns (UC), Grade 350
| Designation | d (mm) | bf (mm) | tf (mm) | tw (mm) | Mass (kg/m) |
|---|---|---|---|---|---|
| 100 UC 14.8 | 97 | 99 | 7.0 | 5.0 | 14.8 |
| 150 UC 23.4 | 152 | 152 | 6.8 | 6.1 | 23.4 |
| 150 UC 30.0 | 157 | 153 | 9.4 | 6.6 | 30.0 |
| 150 UC 37.2 | 162 | 154 | 11.5 | 8.1 | 37.2 |
| 200 UC 46.2 | 203 | 203 | 11.0 | 7.3 | 46.2 |
| 200 UC 52.2 | 206 | 204 | 12.5 | 7.9 | 52.2 |
| 200 UC 59.5 | 210 | 205 | 14.2 | 9.3 | 59.5 |
| 250 UC 72.9 | 254 | 254 | 14.2 | 8.6 | 72.9 |
| 250 UC 89.5 | 260 | 256 | 17.3 | 10.5 | 89.5 |
| 310 UC 96.8 | 302 | 305 | 15.4 | 9.9 | 96.8 |
| 310 UC 118 | 308 | 307 | 18.7 | 11.9 | 118 |
| 310 UC 137 | 321 | 309 | 21.7 | 13.8 | 137 |
ACRS Certification Requirements
For structural sections supplied under AS/NZS 3679.1, the Australasian Certification Authority for Reinforcing and Structural Steels (ACRS) provides the primary independent product certification scheme in Australia and New Zealand. ACRS certification for structural sections involves:
- Annual plant audits of rolling mill processes and quality systems
- Surveillance testing of in-production material
- Verification that supplied sections consistently meet grade, composition, and mechanical requirements of AS/NZS 3679.1
The National Construction Code (NCC) and AS 4100 (Steel Structures) reference material compliance with AS/NZS 3679.1. Many project specifications and state procurement policies require ACRS-certified product. The ACRS certificate number, scheme category, and expiry date should be recorded in the project material documentation.
Cross-Standard Equivalents
| AS/NZS 3679.1 Grade | ASTM Equivalent | EN 10025 Equivalent | BS 4360 (historical) | JIS G3101 |
|---|---|---|---|---|
| 300 | A36 / A572 Gr 42 | S275JR | Grade 43A/B | SS400 / SM400 |
| 300 L0 | A36 (+ supplementary CVN) | S275J0 | Grade 43C | SM400B |
| 300 L15 | A36 (+ supplementary CVN) | S275J2 | Grade 43D | SM400C |
| 350 | A572 Gr 50 | S355JR | Grade 50A/B | SM490 |
| 350 L0 | A572 Gr 50 (+ CVN) | S355J0 | Grade 50C | SM490B |
| 350 L15 | A572 Gr 50 (+ CVN) | S355J2 | Grade 50D | SM490C |
MTC Verification Checklist
- Standard shown as
AS/NZS 3679.1 - Grade and sub-grade match purchase order (e.g.,
350L0, not just350) - Section designation matches ordered product (e.g.,
310 UB 46.2) - Heat (cast) number traceable to physical section markings
- C, Mn, Si, P, S within grade limits; CEV ≤ limit for flange thickness
- ReH ≥ minimum for flange thickness range; Rm ≥ 480 MPa (Grade 350)
- Elongation ≥ 22%
- Charpy results reported if L0 or L15 ordered — three individual values and average
- Mass per metre within ±2.5% tolerance
- ACRS certificate number noted
- MTC signed by authorised mill representative
Frequently Asked Questions
What is the difference between Grade 300 and Grade 350 in AS/NZS 3679.1?
Grade 350 has a higher minimum yield strength (360 MPa for flanges ≤ 11 mm vs 320 MPa for Grade 300 at the same thickness) and a lower maximum CEV (0.48 vs 0.46), reflecting slightly tighter composition control. Tensile strength minimums are also higher for Grade 350 (480 MPa vs 440 MPa). Grade 350 is the more commonly stocked grade in Australia. Both grades are available with L0 and L15 Charpy sub-grades.
Does AS/NZS 3679.1 cover rectangular hollow sections (RHS)?
No. AS/NZS 3679.1 covers only hot-rolled open sections (UB, UC, PFC, EA, UA) and flat and round bars. Cold-formed hollow sections such as RHS, SHS, and CHS are covered by AS/NZS 1163, which uses a separate grade designation system (C250L0, C350L0, C450L0).
What is the standard section designation system used in AS/NZS 3679.1?
Sections are designated by a number representing the nominal depth in millimetres, the section type code (UB, UC, PFC, EA, UA), and the nominal mass per metre in kg/m. For example, 310 UB 46.2 is a Universal Beam of approximately 310 mm depth weighing 46.2 kg per metre. Equal angles are designated by leg size and thickness, e.g., 150×150×12 EA.
Are Australian UB and UC sections the same as British or European sections?
No. While the nomenclature is similar, Australian UB and UC section sizes are unique to AS/NZS 3679.1 and are not dimensionally interchangeable with British Universal Beams (BS 4-1) or European IPE/HE sections (EN 10365). Depth, flange width, and mass per metre differ. Always use the AS/NZS section property tables when designing to AS 4100.
Can Grade 350 sections be welded without preheat?
For most standard section thicknesses, Grade 350 can be welded without preheat provided the CEV is ≤ 0.43 and the combined thickness is not excessive. AS/NZS 1554 (Welding of Steel Structures) provides the preheat requirements based on CEV, combined thickness, and hydrogen content of the electrode. Grade 350's maximum CEV of 0.48–0.50 means preheat may be required for thicker flanges or higher-heat-input processes.
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