What are the mechanical properties required for gbt8890 copper alloy tube?

If you are sourcing copper-nickel or brass tubes for a condenser, heat exchanger, or cooling system, the mechanical properties required by GB/T 8890 are among the first things you need to check. This Chinese national standard sets the tensile strength and elongation values that every seamless copper alloy tube must meet before it can be accepted for service. In this article, we break down the standard, the grades it covers, and the exact mechanical property requirements for each one, so you can specify and verify your tubes with confidence.

What is GB/T 8890?

GB/T 8890, officially titled Seamless copper alloy tube for condenser and heat-exchanger, is the Chinese national standard that governs seamless copper alloy round tubes used to build heat exchangers and condensers. It applies across thermal power generation, naval vessels and ships, offshore oil, machinery, and chemical industries. The standard defines requirements for chemical composition, dimensions and tolerances, mechanical properties, process performance, residual stress, non-destructive testing, grain size, and surface quality, together with the test methods and inspection rules used to verify them.

The current edition is GB/T 8890-2015, published on 11 September 2015 and implemented on 1 April 2016, replacing the earlier GB/T 8890-2007. The 2015 edition introduced alloy designations, updated grade names and temper states to the new national convention, and added grades such as HSn72-1, BFe10-1.4-1, and BFe30-0.7. If your project documentation still refers to the 2007 edition, it is worth confirming that your supplier can certify to the current version.

Which grades does GB/T 8890 cover?

The standard covers two main families of copper alloys used for heat transfer service:

• Copper-nickel (cupronickel) alloys: BFe30-1-1 (the 70/30 Cu-Ni grade, close to UNS C71500), BFe30-0.7, BFe10-1-1 (the 90/10 Cu-Ni grade, close to UNS C70600), and BFe10-1.4-1.
• Brass alloys: HAl77-2 (aluminum brass, close to C68700), HSn72-1 (close to C44300), HSn70-1 and its arsenic-modified variants HSn70-1-0.01 and HSn70-1-0.01-0.04, plus HAs68-0.04, HAs70-0.05, and HAs85-0.05.

Copper-nickel alloys are the first choice for seawater and marine cooling duty because of their outstanding resistance to seawater corrosion and biofouling, while the brass grades are widely used in freshwater condensers and general heat exchange equipment where their combination of strength, thermal conductivity, and cost makes them attractive.

Temper states defined by the standard

Before looking at the numbers, it helps to understand the three temper states used in GB/T 8890-2015, because the mechanical properties are tied directly to the delivery condition:

• O60 — soft annealed, offering maximum ductility for severe forming such as bending and flaring.
• O82 — annealed to half-hard, balancing strength with workability for most heat exchanger applications.
• H80 — hard, cold-worked condition with the highest strength and reduced ductility.

Mechanical properties required by GB/T 8890

The room-temperature mechanical properties are specified in Table 9 of GB/T 8890-2015, expressed as minimum tensile strength (Rm) and minimum elongation after fracture (A). The values for the main grades are summarised below:

A few points are worth noting when reading this table. First, the 70/30 copper-nickel grade BFe30-1-1 delivers the highest strength of the cupronickel family, which is why it is preferred for demanding marine condensers and high-pressure heat exchange service. Second, the hard (H80) condition of BFe10-1-1 reaches a tensile strength of at least 480 MPa, but because it has almost no specified ductility, it is rarely used where the tube must be flared or bent after delivery. Third, the elongation values are measured on standard tensile test pieces, so they reflect the material’s true formability rather than a nominal figure.

How the mechanical properties are verified

Meeting the numbers on paper is only half the story; the standard also defines how they must be verified. Room-temperature tensile testing is carried out in accordance with GB/T 228.1-2010, with test specimens prepared and selected according to the tube outside diameter. Two tubes are taken at random from each batch, with one specimen from each tube, so the result represents the whole batch rather than a single piece.

Beyond the tensile test, GB/T 8890 requires process performance checks that confirm the tube can be worked without cracking. Tubes with an outside diameter up to 100 mm undergo a flaring test using a 45° mandrel, while larger tubes are checked by a flattening test. Brass tubes must also pass a residual stress test, typically the ammonia test, to guard against stress corrosion cracking in service. Every tube is additionally subject to eddy current testing, and hydrostatic or pneumatic testing can be specified by agreement between buyer and supplier. For the annealed O60 condition, the standard also allows a grain size check, with the average grain size expected to fall in the 0.010–0.050 mm range, which keeps the material fine-grained and consistent.

Choosing the right grade for your application

The mechanical property table is your starting point for grade selection, but the operating environment matters just as much:

• Seawater and marine cooling: choose BFe30-1-1 or BFe10-1-1. The higher-strength BFe30-1-1 suits high-pressure and high-velocity seawater systems, while BFe10-1-1 offers excellent corrosion resistance at a lower cost.
• Freshwater condensers and general heat exchange: HAl77-2 and HSn70-1 are proven, economical choices with good thermal performance.
• Severe forming after delivery: specify the O60 soft-annealed condition, which provides the highest elongation for flaring, bending, and tube expansion during installation.
• High-pressure duty: the O82 half-hard condition of BFe30-1-1 gives a good balance of strength and ductility.

Whatever grade you settle on, always confirm the required temper state, the exact dimensions, and the testing and certification requirements in your purchase order, because these determine both the mechanical properties you receive and the documentation you get with the shipment.

Where to source GB/T 8890 compliant tubes

Finding a supplier who can deliver GB/T 8890 compliant tubes with full mill test certificates and reliable mechanical properties is the final piece of the puzzle. EZ Steel Industrial Co., Ltd. is an experienced manufacturer and integrated supplier of industrial metal piping systems, producing and supplying copper-nickel and brass tubes for heat exchangers and condensers in accordance with GB/T 8890, together with matching pipe fittings, flanges, and fasteners for complete project supply. With more than 500 employees, an annual production capacity of over 480,000 tons, and quality management certified to ISO 9001, the company supports EPC contractors, power plants, petrochemical facilities, and marine projects with bundled supply, technical documentation, and just-in-time delivery.

If you need a reliable source of gbt8890 copper alloy tube for your next heat exchanger or condenser project, or you want to compare the performance of copper & nickel alloy tubes against other heat exchanger tube options, the EZ Steel Industrial team can help you match the right grade, temper, and specification to your operating conditions.