ASTM B338 vs B861 vs B862

ASTM B338 covers seamless and welded tubes for heat exchangers and condensers.

ASTM B861 covers seamless pipe for general service.

ASTM B862 covers welded tube for general service.

All three can be made from titanium grade 1. The difference is in the application, the dimensional tolerances, and the required tests.

ASTM B338 grade 1 is the spec for heat exchanger tubes.

If you are building a shell-and-tube heat exchanger, this is what you need. The spec includes special tests that matter for U-bend tubes and thin wall applications.

What makes B338 different:

Tighter wall thickness tolerances

Flattening test to check ductility

Flaring test to check expansion capability

Reverse flattening test for welded tube

Eddy current testing or hydrostatic test required

Gr1 titanium heat exchanger tubes are commonly ordered to B338. The U-bends need the formability of GR1, and the spec ensures the tube can survive the bending process.

ASTM B861 grade 1 is the standard spec for seamless titanium pipe.

Use this for general industrial piping systems. Chemical transfer lines. Marine piping. Pressure piping that does not require heat exchanger tolerances.

What B861 covers:

Seamless pipe from small diameters up to large sizes

Schedule 5S, 10S, 40S, and custom wall thicknesses

Standard tolerances per ASTM

Hydrostatic test or eddy current test required

Optional flattening test (not always required)

Most gr1 titanium pipe orders for general service are B861. It is the default spec unless you have a reason to use something else.

ASTM B862 gr1 is the spec for welded titanium tube.

The tube is formed from strip, welded longitudinally, and then annealed. The weld seam is full penetration and the tube is tested to ensure seam quality.

What B862 covers:

Welded tube only (not seamless)

Sizes typically smaller than B861 pipe

Flattening test to check weld ductility

Reverse flattening test for the weld seam

Hydrostatic or eddy current test

Why choose B862 over B861:

Lower cost than seamless for same dimensions

Good for non-critical applications

Available in longer lengths than seamless

But there is a trade-off. The weld seam is a potential failure point under vibration or cyclic loading. For heat exchanger tubes, B338 welded is acceptable in some cases. For high pressure or critical service, seamless B861 is safer.

Here is when you can substitute:

Low pressure heat exchanger with straight tubes (no U-bends)

Non-code application where the buyer accepts B861

Temporary replacement where tolerances are not critical

Here is when you cannot substitute:

U-bend tubes that need to be bent to a tight radius

Code stamped heat exchanger (ASME Section VIII)

Any application that specifically calls out B338 on the drawing

If you are unsure, send your spec to us. We will tell you when B861 will work and when it will not.

ASTM B338 grade 1 (seamless tube):

Tensile test

Flattening test

Flaring test

Hydrostatic or eddy current test

Hardness test (when specified)

ASTM B338 grade 1 (welded tube):

Tensile test

Flattening test

Reverse flattening test (weld at 90 degrees)

Flaring test

Hydrostatic or eddy current test

Weld seam radiography (when specified)

ASTM B861 grade 1:

Tensile test

Hydrostatic or eddy current test

Flattening test (only when specified)

ASTM B862 gr1:

Tensile test

Flattening test

Reverse flattening test

Hydrostatic or eddy current test

Is this for a heat exchanger? If yes, start with B338.

Does the part need to be bent or formed? If yes, B338 has the flattening test.

Is seamless required by code? If yes, B861.

1. What does ASTM stand for?

American Society for Testing and Materials. They write the standards that define material properties, testing methods, and tolerances.

2. Is B338 only for GR1 titanium?

No. B338 covers GR1, GR2, GR3, GR7, GR11, GR12, GR16, GR17, and GR26. GR1 is the most common for heat exchanger tubes because of its formability.

3. Can B861 pipe be used for a heat exchanger shell?

Yes. The shell is not formed into U-bends. B861 seamless pipe works fine for the shell side. Use B338 for the tubes only.

4. Is B862 welded tube weaker than B861 seamless pipe?

The weld seam is the potential weak point. Properly made B862 welded tube has a weld strength factor of 0.85 to 1.0 depending on the specification. For non-critical applications, B862 is fine. For high pressure or cyclic service, use B861 seamless.

5. What is the difference between tube and pipe?

Tube is measured by outside diameter. Pipe is measured by nominal pipe size (NPS). But in titanium specifications, the terms overlap. B338 calls it tube. B861 calls it pipe. Both are sold by OD and wall thickness.

6. Do I need a mill certificate for each spec?

Yes. Every order should come with a mill test report showing heat number, chemical composition, tensile results, and the required tests for that spec. If a gr1 titanium tube supplier cannot provide a full MTR, find another supplier.

7. Can I get customized gr1 titanium tube to a non-standard spec?

Yes. Customized gr1 titanium tube can be made to your dimensional requirements. But the ASTM spec still applies for testing and tolerances. Tell us the OD, wall, length, and which ASTM spec you need.

8. Which spec is best for gr1 titanium for deep drawing?

ASTM B338 has the flattening and flaring tests that confirm ductility. For deep drawn parts, B338 is a safer choice than B861.

9. What is the difference between ASTM B338 grade 1 and ASME SB338?

No difference. ASME adopts ASTM standards for boiler and pressure vessel code. SB338 is the ASME version of B338. Same material, same tests, same tolerances.

10. Does B861 require a hydrostatic test?

Yes. B861 requires either a hydrostatic test or an eddy current test. Most seamless pipe is eddy current tested unless the buyer specifically asks for hydrostatic.

11. Can B862 welded tube be used for heat exchanger U-bends?

It depends. Some heat exchanger applications allow welded tube for U-bends. The weld seam must be placed on the neutral axis of the bend. The tube must pass the flattening and reverse flattening tests. Check your project specification before ordering.

12. What is the typical lead time for B338 grade 1 tube?

B338 tube is often made to order because the tolerances are tighter. Lead time is typically 4 to 8 weeks for custom sizes. Standard sizes may be in stock. Ask us for gr1 titanium tube in stock before placing a custom order.

13. Which spec is cheaper: B861 or B862?

B862 welded tube is cheaper than B861 seamless pipe. The manufacturing process is simpler. For the same OD and wall thickness, expect B862 to cost 15 to 25 percent less than B861.

Every order of ASTM B338 grade 1, ASTM B861 grade 1, and ASTM B862 gr1 goes through standard testing before shipment.

Chemical composition analysis. We verify oxygen, iron, carbon, nitrogen, and hydrogen are within titanium grade 1 composition limits.

Tensile testing. We confirm ultimate tensile strength, yield strength, and elongation meet the spec requirements.

Flattening test. For B338 and B862, we flatten a sample to check for cracking.

Flaring test. For B338 seamless tube, we flare a sample to check expansion ductility.

Reverse flattening test. For B862 welded tube, we flatten the tube with the weld seam at 90 degrees to the compression direction.

Hydrostatic or eddy current testing. Required for all three specs.

Hardness testing. Performed when specified.

PMI (Positive Material Identification). 100 percent of shipments are verified by PMI before packing.

Third party inspection is available. SGS, Bureau Veritas, TUV, or your chosen agency can witness testing and release the material.

Titanium is soft. Surface scratches can cause failure in heat exchanger tubes. We package carefully.

Individual wrapping. Each tube is wrapped in VCI paper or plastic film.

Layer separation. Wood or plastic spacers go between layers to prevent rubbing.

End caps. Plastic caps on both ends of every tube.

Bundling. Steel straps with edge protectors hold the bundle together.

Waterproofing. Shrink wrap or tarpaulin for sea freight containers.

Labeling. Heat number, size, grade, quantity, and ASTM spec on each bundle.

Pipe and tube production lines:

Piercing mill for seamless pipe up to 325mm OD

3 roll continuous mill for precision seamless

Pilger mill for heavy wall and large diameter tube

Tube reducer for sizing and wall reduction

Welded tube mill for ASTM B862 gr1

Heat treatment furnace for annealing and stress relieving

Finishing and inspection:

7 roll straightening machine

11 roll precision straightening machine

Cutting and chamfering lines

Ultrasonic testing (UT) for flaw detection

Eddy current testing (ET) for surface inspection

Hydrostatic pressure tester

Hardness tester (Rockwell and Vickers)

Optical emission spectrometer (OES) for chemistry