What is the difference between GBT 5310 steel tube and GB 3087 boiler tubes?

When a procurement engineer or boiler designer opens a Chinese pipe standard catalogue, two national standards almost always appear side by side: GB/T 3087 and GB/T 5310. Both are seamless carbon and alloy steel tubes used in boilers, and both share Chinese national (GB) numbering, so the temptation is to treat them as interchangeable. They are not. Choosing the wrong one for a given service can mean an over-engineered project, a non-compliant boiler, or — in the worst case — a tube failure under high-temperature creep. This guide explains how the two standards differ in scope, materials, mechanical properties, dimensional tolerance, testing, and typical applications, so you can pick the right tube for the right job with confidence.

Quick answer: scope and service envelope

In one sentence, GB/T 3087 covers seamless steel tubes for low and medium-pressure boilers (working pressure generally up to about 5.9 MPa, metal temperature up to about 450 °C), while GB/T 5310 covers seamless steel tubes for high-pressure boilers (working pressure typically above 9.8 MPa, metal temperature from about 450 °C up to 650 °C). GB/T 5310 also permits a much wider range of alloy and stainless steel grades and demands stricter testing. If your service is below the GB/T 3087 envelope, GB/T 3087 is usually more economical; if you go above it, GB/T 5310 is mandatory.

Side-by-side comparison at a glance

Where each standard fits in a boiler system

Think of a utility boiler as several temperature zones. On the cooler side — economizer inlet tubes, low-temperature sections of the water-wall, and air preheater connections — the metal rarely exceeds 400 °C and pressures stay modest. GB/T 3087 tubes in grade 20 are perfectly adequate here and offer the best cost. As steam moves toward the furnace exit, it enters the superheater and reheater, where metal temperatures climb above 450 °C and pressures rise into the high-pressure range. This is exactly the territory of GB/T 5310, where carbon grades such as 20G are still used at the cooler end, but alloy grades like 15CrMoG, 12Cr1MoVG, and the 9–12% Cr steels (P91, P92) take over once creep and oxidation resistance become critical. In supercritical and ultra-supercritical units (≥ 24 MPa, ≥ 600 °C), only the GB/T 5310 family — often combined with ASME SA-213 / SA-335 equivalents — is acceptable.

Materials and chemistry: why the alloy range matters

GB/T 3087 limits steel to two quality carbon grades (designated 10 and 20 in GB/T 699). Both have very simple chemistries — essentially iron, carbon, manganese, silicon, and trace residuals — and rely on carbon content and normalization to achieve strength. They are easy to produce, easy to weld, and inexpensive, but their creep strength collapses above about 450 °C.

GB/T 5310 keeps 20G (a normalized carbon grade roughly equivalent to ASME SA-210 Grade A-1/C) as the baseline for moderate high-pressure service, but extends the catalogue with a family of alloy and stainless grades specifically designed for high-temperature strength. Manganese is boosted in 20MnG and 25MnG for higher yield strength; chromium and molybdenum are added in 15CrMoG, 12Cr1MoVG, and 12Cr2MoG for creep resistance; 9–12% Cr martensitic steels such as 10Cr9Mo1VNbN (P91) and 10Cr9MoW2VNbBN (P92) push the envelope to 600–650 °C; and austenitic stainless grades such as 1Cr18Ni9 (304) and 1Cr18Ni11Nb (347H) handle the highest temperatures plus corrosive flue-gas environments. Mandatory ladle refining and vacuum degassing lower sulfur, oxygen, and hydrogen contents, which directly improves creep life and impact toughness.

Mechanical properties and high-temperature performance

For GB/T 3087 in grade 20, room-temperature tensile strength is typically 410–550 MPa with yield strength ≥ 245 MPa and elongation ≥ 20%. These values are sufficient for low-to-medium pressure service but the allowable stress drops sharply above 400 °C.

For GB/T 5310, the room-temperature properties are similar for 20G, but the high-temperature yield and creep rupture strength — the values that actually matter in boiler design — are far higher. The standard also requires an elevated-temperature tensile test at 350 °C or above for many grades, and the designer can calculate allowable stresses from the tabulated high-temperature strength data. A direct consequence is that a GB/T 3087 tube and a GB/T 5310 tube of the same outer diameter and wall thickness do not have the same design life in a superheater; the GB/T 5310 tube can run hotter for longer.

Dimensional tolerance and surface quality

Dimensional precision is more important in high-pressure service because wall thickness directly drives pressure and creep calculations. GB/T 5310 therefore tightens the permissible deviations, particularly for small-diameter cold-drawn tubes used as instrument tubing and for the hot-finished large-diameter pipes used in main steam and header lines. Both standards require ends cut square and deburred, and bevelling on tubes above 60 mm OD. Surface defects that would be acceptable in a low-pressure air line can act as stress raisers and initiate creep cracks in a high-pressure superheater, so GB/T 5310 also imposes stricter surface inspection and rejects more strictly.

Testing, inspection, and documentation

GB/T 3087 testing is batch-oriented: tensile, flattening, drift-expand, and a hydrostatic test on each tube (or an alternative eddy-current test by agreement). Mill test certificates are issued in the standard 3.1 or 3.2 format. GB/T 5310 adds 100% non-destructive testing (ultrasonic or eddy current) on every single tube, plus impact testing at low or ambient temperature, hardness testing, and — where specified — high-temperature tensile and creep testing. This is one of the main reasons GB/T 5310 costs more per kilogram: every tube is individually scanned, and the documentation package is significantly heavier.

Selecting the right standard for your project

Use this simple flow when you receive a project specification:

1. Confirm design pressure and metal temperature. If both are below the GB/T 3087 envelope, specify GB/T 3087 grade 20.
2. Check the boiler cycle. Subcritical, supercritical, or ultra-supercritical units require GB/T 5310 — there is no realistic alternative for the high-temperature sections.
3. Match the grade to the service. 20G for water-wall and headers; 15CrMoG or 12Cr1MoVG for superheater and reheater; P91/P92 for ultra-supercritical main steam; 304/347H stainless for the most corrosive or highest-temperature zones.
4. Specify the delivery condition. Always state heat-treatment, end finish, NDT level, and MTC format (EN 10204 3.1 or 3.2) on the purchase order.
5. Plan the documentation up front. If your project follows ASME, request dual certification (e.g., GB/T 5310 + ASME SA-213 / SA-335) to simplify cross-checks during inspection.

If you are unsure which standard applies, send your design pressure, metal temperature, fluid, and the relevant boiler component to a supplier who stocks both families — they can usually point you to the correct grade within an hour.

How EZ Steel Industrial supports both standards

As an integrated manufacturer of industrial metal piping systems, EZ Steel Industrial produces both GB5310 alloy steel tubes for high-pressure boiler service and the wider carbon-steel ASTM A335 alloy steel pipes and high-pressure carbon and alloy steel pipes that complement them. For low-and-medium pressure boiler assemblies, the company also supplies JIS G 3461 carbon steel tubes and equivalent carbon-grade products, along with matching pipe fittings and pipe flanges so that an entire boiler piping package can be sourced from one supplier.

All tubes are produced under an ISO 9001 quality system with API 5L / API 5CT product certification and PED compliance where required. Manufacturing is supported by CNC machining, robotic welding, and inline non-destructive testing (X-ray and ultrasonic), with more than twelve documented quality checkpoints from steelmaking to final inspection. Mill test certificates in EN 10204 3.1 / 3.2 format are issued as standard, and just-in-time delivery is available for both EPC contractors and equipment manufacturers.

FAQ

Can GB/T 3087 be used for superheater tubes?
No. Once the metal temperature regularly exceeds 450 °C, GB/T 3087 grade 20 does not have sufficient creep strength. You must switch to GB/T 5310, starting with 15CrMoG for moderate superheat and moving to 12Cr1MoVG or P91/P92 for higher temperatures.

Is GB/T 3087 grade 20 the same as ASTM A106 Grade B?
They are close equivalents in room-temperature strength and chemistry, but they are not interchangeable in all services. ASTM A106 covers high-temperature carbon steel pipe for refinery and power service; GB/T 3087 is specifically scoped to low-and-medium pressure boilers. Always check the design code of your project before substituting.

Do I need a special welding procedure for GB/T 5310 alloy grades?
Yes. Alloy grades such as 12Cr1MoVG and P91 require preheat, controlled interpass temperature, and post-weld heat treatment. A qualified WPS/PQR per ASME IX or GB/T 19869 is mandatory.

What documentation should I receive with each delivery?
At minimum: mill test certificate (EN 10204 3.1), dimensional inspection report, NDT report, hydrostatic test report, and material traceability list with heat numbers. For critical service, request 3.2 certification witnessed by a third party such as SGS, TÜV, or BV.

Key takeaways

• GB/T 3087 is for low-and-medium pressure boilers (≤ 5.9 MPa, ≤ 450 °C) in carbon steel grades 10 and 20.
• GB/T 5310 is for high-pressure boilers (≥ 9.8 MPa, 450–650 °C) in a wide range of carbon, alloy, and stainless steels.
• Choose GB/T 5310 once the design enters the high-temperature or supercritical range — the difference in creep resistance is not something a thicker wall can compensate for.
• Match the grade, delivery condition, NDT level, and documentation to the specific component (water-wall, economizer, superheater, header, main steam).
• Work with a manufacturer that produces both families and can deliver EN 10204 3.1/3.2 certificates with full traceability.