Which aluminium alloys are specified for marine use in this standard?

The standard covers alloys like 64430 (HE30), 52000 (NE4), 53000 (NE5), and 54300 (NE8) among others. See Table 1 for the full list and composition.

What are the key mechanical properties for alloy 64430 in the WP temper?

For alloy 64430-WP, the minimum 0.2% proof stress is 255 MPa, minimum tensile strength is 310 MPa, and minimum elongation is 8% (Table 2).

What is the tolerance on the straightness of the tee bars?

The maximum deviation from straightness shall not exceed 2.5 mm in any 1000 mm length of the bar (Clause 6.3).

How should the tee bars be marked?

Each bar should be marked with the alloy and temper designation, and the BIS Certification Mark (Clause 9).

IS 6475

: 1987

Aluminium tee bars for marine application

CurrentSpecializedSpecificationBIMMaterials Science · Structural Engineering and Structural Sections

Download PDF BIS Portal Google

This standard specifies the material requirements, mechanical properties, and dimensional tolerances for extruded aluminium alloy tee bars. It covers specific corrosion-resistant alloys and their tempers suitable for marine applications like shipbuilding and offshore structures.

Aluminium tee bars for marine application

Quick Reference Values

Min 0.2% Proof Stress (Alloy 64430-WP)255 MPa

Min Tensile Strength (Alloy 64430-WP)310 MPa

Min Elongation (Alloy 64430-WP on 50 mm gauge)8 %

Min 0.2% Proof Stress (Alloy 54300-M)140 MPa

Min Tensile Strength (Alloy 54300-M)280 MPa

Max deviation from straightness2.5 mm in any 1000 mm length

Practical Notes

Selection of the correct alloy (e.g., 5xxxx or 6xxxx series) and temper (e.g., WP, M) is critical for achieving the required strength and corrosion resistance in a marine environment.

Always insist on a manufacturer's test certificate to verify compliance with the chemical composition and mechanical properties specified in this standard.

Pay close attention to dimensional and straightness tolerances (Clause 6), as these are critical for fit-up and fabrication.