China AS/NZS 1163 C350 CHS Exporters: A Practical Sourcing Guide

Buying AS/NZS 1163 C350 circular hollow sections (CHS) from China requires more than comparing prices per tonne. The purchaser must confirm the steel grade, dimensions, mechanical test results, documentation and delivery terms against the project’s specification. A clear request for quotation helps a manufacturer establish whether the required product can be supplied and tested. This guide focuses on C350 circular sections, supplier assessment and export documentation for structural projects.

What Is AS/NZS 1163 C350 CHS?

AS/NZS 1163 specifies requirements for cold-formed structural steel hollow sections. Its scope includes circular, square and rectangular sections; however, these are different product shapes and should not be treated as interchangeable. LONGMA’s structural pipe offering focuses on circular welded steel pipe manufactured by ERW and LSAW processes, rather than square or rectangular hollow sections.

C350 identifies a nominal minimum yield-strength grade of 350 MPa within the standard’s applicable conditions. A grade name alone does not establish full compliance. The applicable edition, dimensions, chemical composition, tensile properties, testing and inspection requirements must also be confirmed. C350L0 adds specified impact-performance requirements for applications where that designation is needed. The precise acceptance criteria should be taken from the edition named in the contract, including any relevant test-piece conditions.

The designation AS/NZS 1163 should not be confused with AS/NZS 4680. The former concerns structural hollow-section products; the latter concerns hot-dip galvanized coatings on fabricated ferrous articles. A galvanized C350 CHS order may therefore need separate requirements for both the steel and the protective finish.

Mechanical Properties and Product Specifications

The key mechanical properties to review are yield strength, tensile strength, elongation and, when specified, impact toughness. These properties serve different purposes. Yield strength helps establish the onset of plastic deformation, tensile strength characterizes maximum engineering stress in a tensile test, and elongation provides information about ductility. None of these results alone proves that a member is adequate for a particular structural load.

For C350, 350 MPa is the grade’s nominal minimum yield-strength designation, subject to the standard’s applicable requirements. Avoid using a simplified marketing table as a substitute for the complete standard. Acceptance values for tensile strength, elongation and impact testing must be checked against the specified edition and relevant product conditions. A C350L0 designation should be ordered explicitly where the project requires that impact grade.

A complete CHS inquiry should identify the outside diameter, nominal wall thickness, length, grade, quantity, end condition and surface finish. Dimensional tolerances should be those required by the product standard and purchase agreement. Wall thickness affects cross-sectional area, mass, local slenderness and structural resistance, but a thicker wall does not automatically make a member suitable for every load case.

For a quick estimate of uncoated circular steel-pipe mass, purchasers may use the nominal dimensions and a steel density of approximately 7,850 kg/m³. Actual shipment mass can differ because of manufacturing tolerances, coatings and cutting. The purchase contract should specify whether quantity is settled by theoretical or actual mass.

C350 Compared With Other Structural Grades

C250, C350 and C450 are different strength designations within the AS/NZS 1163 family. Higher nominal yield strength can permit a different section selection, but it does not guarantee a lighter or less expensive structure. Buckling, connection design, fabrication, service temperature and availability must be assessed together. The structural engineer should select the grade and dimensions rather than relying on a strength-number comparison alone.

ASTM A500 Grade C is not an automatic replacement for AS/NZS 1163 C350. The standards differ in their product provisions, test requirements and acceptance rules. Even when individual mechanical properties appear similar, the substitution requires a documented technical review and approval where the project permits it. The same principle applies to European structural hollow-section grades such as those specified under EN 10219.

Circular sections can be attractive for columns, trusses and members exposed to loads from several directions. Their closed geometry provides useful torsional behavior, while connection details and fabrication methods may differ from those for open sections or rectangular profiles. These are design considerations, not a guarantee of superior performance in every application.

How to Verify a Chinese C350 CHS Supplier

A supplier assessment should begin with manufacturing scope. Ask whether the supplier produces the requested circular section and whether the proposed manufacturing route, size range and grade can meet the contract. Do not assume that a supplier of CHS also manufactures SHS or RHS, or that a supplier’s general catalog establishes availability of every listed size.

Review a sample mill test certificate before placing an order. The certificate should identify the product, applicable standard, grade, heat or batch reference and relevant chemical and mechanical test results. Where EN 10204 type 3.1 documentation is required, specify it in the purchase order; it is a defined inspection-document type, not a universal requirement for every export shipment.

The buyer should also request the dimensional inspection scope, marking method and traceability procedure. A useful traceability chain connects the incoming material record, production batch, finished pipe marking and shipping documents. Independent inspection can be arranged where required by the contract or risk assessment. ISO 9001 certification relates to a quality-management system; it does not by itself certify every individual pipe as compliant. Likewise, ISO/IEC 17025 accreditation concerns the competence of testing and calibration laboratories, not a blanket obligation that every manufacturer’s internal laboratory must hold such accreditation.

Pricing, Packing and Export Documentation

C350 CHS quotations depend on the steel grade, outside diameter, wall thickness, order quantity, length, testing scope, coating, processing and commercial terms. Compare quotations on the same technical basis. A lower price is not directly comparable if it excludes inspection, protective coating, end preparation or a document package specified elsewhere.

For international shipments, clarify the agreed Incoterms rule and named place or port. Under FOB, the seller’s delivery obligation differs from that under CIF or DAP; responsibilities for freight, insurance and import clearance must be read from the chosen rule rather than assumed. Local import duties, taxes and regulatory requirements should be checked with the relevant authorities or logistics advisers.

Packing should protect pipe ends, surfaces and identification markings. Bundles should be identified so that grade, size and heat or batch information can be matched with the packing list. Confirm loading arrangements, permissible transport weight, protective measures against handling damage and the documents needed by the destination. A typical documentation package may include a commercial invoice, packing list, transport document, material certificate and any project-specific inspection records.

Common Procurement Mistakes and How to Avoid Them

The most common specification problem is ordering by grade alone. “C350 pipe” does not identify diameter, thickness, length, impact designation or coating. Another problem is treating a certificate for a different standard as proof of compliance without a technical comparison. Buyers should also avoid accepting an undocumented grade substitution or assuming that a supplier’s general production capacity confirms the availability of a particular specification.

Before approving production, review the technical offer against the drawing and purchase order. Confirm the grade designation, dimensional tolerances, test and inspection requirements, marking, certificates and delivery schedule. Agree on how nonconforming material will be identified and handled. Where galvanized sections are ordered, define the coating specification and any fabrication requirements separately from the base steel specification.

A well-structured request for quotation reduces avoidable clarification rounds. It should state the intended application, relevant standard edition, grade, dimensions, quantities, finish, inspection requirements, destination and delivery terms. If an engineer has approved a substitute material, include that approval rather than relying on verbal equivalence claims.

Frequently Asked Questions

Is AS/NZS 1163 C350 the same as ASTM A500 Grade C?

No. They are separate product standards with different requirements. Substitution should be reviewed and approved for the particular project.

Does C350 automatically require impact testing?

The required impact designation and test conditions depend on the specified grade and project requirements. Specify C350L0 when that designation is required and verify its acceptance criteria against the governing standard.

Can LONGMA supply C350 square or rectangular hollow sections?

LONGMA’s product focus is circular ERW and LSAW welded steel pipe. The fact that AS/NZS 1163 also covers square and rectangular profiles does not mean those shapes are part of LONGMA’s product range.

What should buyers send with an RFQ?

Include the standard and edition, grade, CHS outside diameter, wall thickness, length, quantity, surface finish, test and certificate requirements, destination and requested delivery terms.

About LONGMA

LONGMA has more than 20 years of experience in round welded steel pipe manufacturing, with ERW and LSAW production capabilities, a 230,000 m² manufacturing site and annual production exceeding 500,000 tonnes. For a project-specific review of circular structural pipe requirements, send your specification and inquiry to info@ilongma.com. Product availability and compliance should be confirmed against the exact order requirements.