NZS 1163 is the standard of New Zealand. Its full name is "Cold-formed structural steel hollow sections", and it is translated into Chinese as "Hollow Steel Tubes for Cold-formed Structures".

In simple terms, it is a technical specification that stipulates the material, manufacturing process, dimensional tolerance, mechanical properties and testing methods of cold-formed round, square and rectangular steel pipes used in buildings and engineering structures such as houses, Bridges, stadiums, etc.

Cold-formed:

It refers to the process where steel plates or steel strips are formed by rolling at room temperature and then welded (usually high-frequency resistance welding, HFW) to produce steel pipes. This is different from "hot-rolled" steel pipes that are made by extrusion or piercing at high temperatures.

Hollow sections:

This refers to the situation where the cross-section of a pipe is hollow, including square pipes (SHS), rectangular pipes (RHS), and round pipes (CHS).

Important relationship: NZS 1163 is basically consistent with the Australian AS 1163 standard in terms of technology. In practice, the two countries usually jointly use the joint standard number AS/NZS 1163 to ensure the universality and consistency of products between the two countries. Therefore, you will often see the writing of "AS/NZS 1163".

NZS/AS 1163 steel pipes are mainly used in the fields of construction and structural engineering. Specific applications include:

• Building structure frame: As the main load-bearing component of beams, columns and trusses. Due to its neat appearance, it is often used in modern-style commercial buildings, stadiums, shopping centers, etc.
• Support and bracket systems: Used to provide lateral stability, such as the connection between support beams and columns.
• Spatial frame and roof structure: By taking advantage of its lightweight and high-strength features, large-span roofs can be constructed.
• Bridge structure: A component used for pedestrian overpasses or large Bridges.
• Mechanical and vehicle chassis: In some cases, it is also used to manufacture mechanical frames or trailer chassis that require high strength and rigidity.
• Decoration and fencing: Smaller-sized pipes are also frequently used in railings, handrails, fences, etc., combining functionality and aesthetics.

This standard has a series of strict requirements for steel pipes, mainly including:

1. Grades:

The standard specifies different grades of steel, mainly classified based on their minimum Yield Strength. Common grades include:
◦ C250: Yield strength is 250 MPa

◦ C350: Yield strength is 350 MPa

◦ C450: Yield strength is 450 MPa

(" C "stands for" Cold-formed ")

2. Manufacturing process:

Cold forming and high-frequency welding (HFW) processes must be adopted for manufacturing. The weld seams must be continuous, uniform and fully penetrated.

3. Dimensions and Tolerances:

The allowable deviations for outer diameter, side length, wall thickness, length, etc., as well as the squareness and straightness of the cross-section, are strictly stipulated to ensure accuracy and convenience during construction.

4. Mechanical properties:

In addition to yield Strength, Tensile Strength (Tensile strength), Elongation (Elongation) and other indicators are also specified to ensure that the material has sufficient strength and toughness.

5. Testing and Certification:

Steel pipe manufacturers must conduct a series of tests on their products (such as tensile tests, flattening tests, reverse bending tests, etc.) to ensure compliance with standard requirements. Products usually need to provide certification certificates.

Compared with other types of steel pipes or profiles, the uniqueness of NZS/AS 1163 steel pipes lies in:

1. High structural efficiency

◦ Excellent strength-to-weight ratio: The hollow cross-section enables it to provide extremely high bending and torsional stiffness despite being very light in weight, making it an ideal choice for large-span structures.

◦ Isotropy: The moments of inertia of square tubes and rectangular tubes in all directions are the same or similar, ensuring uniform force-bearing performance and simplifying design and connection.

2. Attractive appearance:

Cold-formed pipes have a smooth surface, precise dimensions, and a neat and modern shape. They are highly suitable for Architecturally Exposed Structural Steel (AESS) designs and can achieve a good visual effect without additional decoration.

3. Easy to process and connect

The cross-sectional shape is regular, making it easy to cut, drill, weld and connect with other components.

The interior is hollow, facilitating wiring (wires, pipes) or filling with concrete (forming composite columns, significantly enhancing load-bearing capacity and fire resistance).

4. Comply with specific regulations of Australia and New Zealand:

As a joint standard of Australia and New Zealand, it fully complies with the requirements of the Australian and New Zealand Building Code (NZS 3404), especially in terms of seismic design. In important structural projects in this region, the use of products that comply with AS/NZS standards is usually mandatory.

5. Differences from hot-rolled pipes (AS/NZS 3679.1) :

Although both are used for structures, cold-formed tubes (AS/NZS 1163) usually have thinner wall thicknesses, better surface treatment and dimensional accuracy, and are more suitable for light to medium precision structures. Hot-rolled tubes (AS/NZS 3679.1) are usually heavier and are used in heavy industrial structures.

NZS 1163 (or AS/NZS 1163) is the authoritative standard for cold-formed hollow steel pipes used in structures in Australia and New Zealand. It defines high-quality and high-performance steel pipe products. With their light weight, high strength, aesthetic appearance, practicality and compliance with local strict standards (especially seismic resistance), they have become one of the most mainstream and preferred structural materials in construction and engineering projects in this region.