What are the marking and packaging requirements for GBT13296 steel tube?

When you order seamless stainless steel tubes to GB/T 13296 for a boiler or heat exchanger project, the tubes themselves are only half the story. The marking, packaging and accompanying quality certificate are what let you trace each tube back to its production heat, confirm it meets the specification, and get it to site in good condition. This article explains what GB/T 13296 requires for marking and packaging, and what you should check when the tubes arrive.

What GB/T 13296 covers

GB/T 13296 is the Chinese national standard for seamless stainless steel tubes for boilers and heat exchangers. The current edition, GB/T 13296-2023, was issued in November 2023 and took effect on 1 June 2024, replacing the 2013 version. It sets out classification, dimensions, technical requirements, test methods, inspection rules, and, importantly, packaging, marking and quality certificate requirements.

The standard applies to seamless stainless steel tubes used in boilers, superheaters, heat exchangers and condensers. Common grades include 06Cr19Ni10 (304), 022Cr19Ni10 (304L), 06Cr17Ni12Mo2 (316), 022Cr17Ni12Mo2 (316L), 06Cr18Ni11Ti (321) and 06Cr25Ni20 (310S). Tubes are delivered heat-treated and acid-pickled, and each one is subject to ultrasonic testing to acceptance level U2 in accordance with GB/T 5777. For a closer look at the full specification, see the gbt13296 steel tube product page.

Marking requirements for GB/T 13296 tubes

Marking is what makes a tube traceable. Under GB/T 13296, marking and packaging follow the general rules of GB/T 2102, the standard covering acceptance, packaging, marking and quality certification of steel tubular products. In practice, each tube should carry the following information:

• Manufacturer's name or trademark
• The standard number, GB/T 13296
• Steel grade or designation, for example 06Cr19Ni10 or 022Cr17Ni12Mo2
• Heat number, which links the tube to its production heat and test records
• Size specification, usually outer diameter and wall thickness
• A traceability identification number where the buyer requires it

Marking can be applied by stamping, printing, roll printing or stencilling, or with attached labels and tags. On small-diameter tubes where marking every single tube is impractical, tags are attached to each bundle instead. The key point is that the marking must survive handling and transport so that each tube can be matched to its heat number and mill test certificate on arrival.

Packaging requirements

Packaging has one job: to get the tubes to site undamaged and free from contamination. For stainless steel, this matters more than it does for carbon steel, because surface damage or contamination can affect corrosion resistance in boiler and heat exchanger service.

Typical packaging requirements for GB/T 13296 tubes include:

• Tubes are bundled and fastened with steel straps or galvanized wire, with straps placed at both ends and at intervals along the bundle so it stays tight during lifting and transport.
• Bundle weight is kept within a practical limit so each bundle can be handled safely with standard lifting equipment. Buyers and suppliers usually agree on the maximum bundle weight at the time of ordering.
• Protective measures such as end caps, wrapping or protective coatings are used to prevent damage to the tube ends and surfaces.
• For stainless steel, care is taken to avoid contact with carbon steel and exposure to chlorides, which can cause surface contamination and pitting.
• Tubes are packed so they can be loaded, unloaded and stored without bending, crushing or scratching.

The quality certificate

Marking and packaging go hand in hand with the quality certificate, sometimes called the mill test certificate. For GB/T 13296 tubes, the certificate should record the manufacturer, the standard number, the steel grade, the heat number and batch number, the delivery condition, the dimensions, the quantity and weight, and the results of the required tests, including chemical composition, mechanical properties and non-destructive testing. This is the document that lets the end user confirm the tubes actually meet the specification, and it is normally required for project documentation in boiler and heat exchanger applications.

What to check when the tubes arrive

When GB/T 13296 tubes arrive on site, a quick check saves problems later:

• Confirm that the marking on the tubes or bundle tags matches the purchase order, including the standard number, grade, heat number and size.
• Check the bundle tags against the quality certificate, and the certificate against the order.
• Inspect the packaging for damage that could indicate the tubes were dropped or crushed in transit.
• Check the tube ends and surfaces for dents, scratches or contamination before installation.

Getting it right from the start

Marking and packaging are not afterthoughts; they are part of the specification. A supplier that understands GB/T 13296 will mark every heat clearly, pack the stainless steel tube properly, and issue a complete quality certificate with every delivery. EZ Steel Industrial supplies gbt13296 steel tube for boilers and heat exchangers with strict dimension tolerances and full documentation, and also provides related boiler tubing and heat exchanger tube solutions across carbon, alloy and stainless grades. If you are sourcing tubes for a project, it is worth confirming the marking, packaging and certificate requirements before you order, and checking them again when the tubes arrive.