Reference for Charpy V-notch (CVN) impact testing per AS/NZS 3679.1:2016 and AS 4100:2020 Clause 2.4.5. Covers L0 and L15 designations, minimum absorbed energy, test temperatures.

Required Charpy by Application

Worked Example per AS 4100 Clause 2.4.5

Problem: Welded tension hanger in an airport terminal roof structure, Canberra ACT (minimum ambient -7°C). Member is a Grade 350 plate, 32 mm thick, with full-penetration butt welds at both ends. Determine Charpy requirements per AS 4100:2020 and AS/NZS 3679.1.

Step 1 — Service Temperature Classification per AS 4100 Clause 2.4.5.1: Canberra minimum ambient = -7°C. Since service temperature < 0°C, Clause 2.4.5.2 applies (members subject to tensile stress at temperatures below 0°C).

Step 2 — Designation Selection per AS/NZS 3679.1 Table 8: Per Clause 2.4.5.2, for ambient < 0°C: L15 required (minimum 27 J at -15°C). L15 provides adequate margin: -15°C test temperature vs -7°C service = 8°C margin.

Step 3 — Through-Thickness Consideration per AS 4100 Supplement 1: For 32 mm plate with welded connections, lamellar tearing risk exists. Per AS/NZS 3679.1 Clause 9, specify through-thickness tensile testing (Z-quality equivalent). Recommended: Z25 (25% minimum reduction of area in through-thickness test per EN 10164 equivalent). Combined spec: Grade 350 L15 with enhanced through-thickness properties.

Step 4 — Testing Requirements per AS/NZS 3679.1 Clause 8.4: One set of 3 Charpy V-notch specimens per heat. Test temperature: -15°C ± 2°C. Acceptance: average of 3 ≥ 27 J, individual minimum ≥ 20 J. If one specimen fails: retest 3 additional specimens from the same heat. All 3 retest specimens must meet the minimum. Failure on retest rejects the material.

Step 5 — Alternative per AS 4100 Clause 2.4.5.4: If L15 material is unavailable, the designer may justify using L0 material under AS 4100 Clause 2.4.5.4 (alternative assessment). For thickness 32 mm and service temperature -7°C, a fracture mechanics assessment per BS 7910 or API 579 may demonstrate adequate toughness. However, this requires detailed analysis and is typically more expensive than specifying L15 directly.

Result: Specify Grade 350 L15 per AS/NZS 3679.1. Charpy: 27 J minimum at -15°C. 3 specimens per heat. Enhanced through-thickness properties for welded tension connection. All testing per AS/NZS 3679.1 Clause 8.4.

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 standard Charpy requirement for Grade 300 steel? L0: min 27 J at 0°C. Grade 300PLUS guarantees 27 J at 0°C for all thicknesses.

When should L15 be specified? Alpine regions, dynamically loaded structures, and tensile stress below -5°C ambient.

What if a Charpy test fails? Retest 3 additional specimens. Failure on retest rejects material per AS/NZS 3679.1 Clause 8.4.

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.

Design Applications

Common Design Scenarios

This reference covers structural design scenarios commonly encountered in Australian steel design practice:

• Strength verification: Check member or connection capacity against factored loads per the applicable design code
• Serviceability checks: Verify deflections, vibrations, and other serviceability criteria
• Code compliance: Ensure design meets all provisions of the governing standard
• Connection detailing: Verify weld sizes, bolt quantities, and edge distances

Related Design Considerations

• System behavior: consider the interaction between members and connections
• Load paths: verify that forces can be transferred through the structure to the foundations
• Constructability: check that the design can be fabricated and erected practically
• Cost optimization: evaluate alternative sections or connection types for economy

Worked Example

Problem: Verify a Grade 300 member for the following conditions:

Typical span: 6.0 m | Load: service loads per applicable code | Section: common section in this category

Design Check:

1. Determine governing load combination (LRFD or ASD per applicable code)
2. Calculate maximum internal forces (moment, shear, axial)
3. Compute nominal capacity per code provisions
4. Apply resistance/safety factors
5. Verify interaction if combined forces exist

Result: Use the results from the Steel Calculator tool to verify design adequacy.

Charpy Impact Testing Requirements per AS 4100

AS 4100 Clause 2.4 specifies Charpy V-notch (CVN) impact testing requirements for fracture-critical steel elements. The minimum absorbed energy depends on the service temperature and stress category:

Testing Temperature Requirements

The Charpy test temperature must be at or below the minimum service temperature. For Australian conditions:

• Standard (interior): 0°C test temperature
• Moderate (coastal): −10°C test temperature
• Severe (mountain/southern): −20°C test temperature or lower

Steel Grade CVN Performance

Typical Charpy values for common Australian grades:

• Grade 300: Typically 27 J at 0°C (standard), satisfies Category 1 for most interior applications
• Grade 350: 27-40 J at 0°C, better notch toughness than Grade 300
• Grade 400: 40-60 J at 0°C, suitable for low-temperature applications
• Grade 450: 60+ J at 0°C— recommended for fracture-critical members in severe environments

Frequently Asked Questions

What Australian Standard governs structural steel design?

AS 4100-2020 (Steel Structures) is the primary standard for structural steel design in Australia. It covers all aspects of design including member capacity, connections, serviceability, and fire resistance. The standard uses a limit states design philosophy with resistance factors (φ) applied to nominal capacities. Companion standards include AS/NZS 3679.1 for hot-rolled sections, AS/NZS 1554 for welding, and AS/NZS 4600 for cold-formed steel.

What are the common steel grades used in Australian construction?

The most common steel grades for Australian construction are Grade 300 and Grade 350 per AS/NZS 3679.1. Grade 300 (minimum yield 300 MPa for sections > 12 mm thick) is the standard for general structural applications. Grade 350 (minimum yield 340 MPa for sections > 12 mm) is used where higher strength reduces weight. Grade 400 and Grade 450 are available for specialized applications requiring higher strength-to-weight ratios.

How does AS 4100 compare to AISC 360?

Both AS 4100 and AISC 360 use limit states design (LRFD) principles. Key differences include: AS 4100 uses a single "capacity factor" φ approach rather than separate φ for different failure modes; AS 4100 specifies distinct buckling curves for hot-rolled and welded sections; the moment capacity formula in AS 4100 uses αm factor directly rather than Cb; and AS 4100 has more detailed provisions for slender sections and combined actions. Despite philosophical differences, both codes produce similar results for typical members.

Related pages

• AS 4100 code provisions
• Australian steel grades chart
• Steel material properties reference
• Fatigue design for steel structures