Why Standards Matter When You Buy or Sell Scrap
A buyer of new Inconel 625 pipe orders it to ASTM B444, UNS N06625. Years later the same pipe comes out of a plant as scrap, and very often that marking is still on it. A readable marking, a heat number that matches a mill certificate and an XRF reading that agrees with both make the strongest proof of grade a scrap lot can have.
Standards also explain why one grade appears under several numbers. Inconel 625 plate is B443, bar is B446, seamless pipe is B444, welded pipe is B705 and forgings are B564. The alloy is the same in each case. The number changes with the product form, so a spec number on its own tells you how the metal was made, not which alloy it is. The UNS number tells you the alloy. See how UNS numbers work.
How to Read a Mill Marking
- ASTM B444 Product specification: seamless pipe and tube in alloy 625
- ASME SB-444 The same specification adopted into the ASME pressure vessel code
- UNS N06625 The alloy: Inconel 625
- GR 2 Grade within the specification (condition)
- 2" SCH 40S Nominal size and wall schedule
- SMLS Seamless
- HT 7C1234 Heat number: links the piece to its mill certificate
Pipe and tube are usually ink-jet printed or stencilled along their length. Plate is stamped or stencilled near a corner. Bar is often tagged or marked on the end. Cutting, blasting and years of service remove markings, so offcuts from a new fabrication shop carry them far more often than material out of a demolished plant.
The Standards Families
Grade-By-Form Cross Reference
The main product specifications for every grade we list. The ASME column shows the equivalent where ASME has adopted the ASTM document. Grades with no public ASTM or AMS specification, such as the René, MAR-M and GTD cast superalloys, are bought to engine-maker specifications and are left out.
| Grade | Plate, sheet | Bar, rod | Pipe, tube | Forgings, fittings | Aerospace | Other |
|---|---|---|---|---|---|---|
| Inconel | ||||||
| Inconel 600N06600 | B168 SB-168 | B166 SB-166 | B167 SB-167B163 SB-163B516 SB-516B517 SB-517 | B564 SB-564B366 SB-366 | AMS 5540AMS 5665 | – |
| Inconel 601N06601 | B168 SB-168 | B166 SB-166 | B167 SB-167B163 SB-163 | – | – | – |
| Inconel 617N06617 | B168 SB-168 | B166 SB-166 | B167 SB-167 | B564 SB-564 | AMS 5888 / AMS 5889AMS 5887 | – |
| Inconel 625N06625 | B443 SB-443 | B446 SB-446 | B444 SB-444B704 SB-704B705 SB-705 | B564 SB-564B366 SB-366 | AMS 5599AMS 5666AMS 5581AMS 5837 | – |
| Inconel 690N06690 | B168 SB-168 | B166 SB-166 | B167 SB-167B163 SB-163 | – | – | – |
| Inconel 713CN07713 | – | – | – | – | AMS 5391 | – |
| Inconel 718N07718 | B670 | B637 | – | – | AMS 5596AMS 5662AMS 5663AMS 5832 | API 6A718 |
| Incoloy | ||||||
| Incoloy 825N08825 | B424 SB-424 | B425 SB-425 | B423 SB-423B163 SB-163B704 SB-704B705 SB-705 | B564 SB-564B366 SB-366 | – | – |
| Incoloy 925N09925 | – | B805 | – | – | – | API 6ACRA |
| Hastelloy | ||||||
| Hastelloy B-2N10665 | B333 SB-333 | B335 SB-335 | B622 SB-622B619 SB-619B626 SB-626 | B366 SB-366 | – | – |
| Hastelloy C-276N10276 | B575 SB-575 | B574 SB-574 | B622 SB-622B619 SB-619B626 SB-626 | B564 SB-564B366 SB-366 | – | – |
| Hastelloy C-22N06022 | B575 SB-575 | B574 SB-574 | B622 SB-622B619 SB-619B626 SB-626 | B564 SB-564B366 SB-366 | – | – |
| Hastelloy XN06002 | B435 SB-435 | B572 SB-572 | B622 SB-622B619 SB-619B626 SB-626 | – | AMS 5536AMS 5754 | – |
| Monel | ||||||
| Monel 400N04400 | B127 SB-127 | B164 SB-164 | B165 SB-165B163 SB-163 | B564 SB-564B366 SB-366 | AMS 4544AMS 4675 | QQ-N-281 |
| Monel K-500N05500 | – | B865 | – | – | AMS 4676 | QQ-N-286 |
| Haynes | ||||||
| Haynes 230N06230 | B435 SB-435 | B572 SB-572 | B622 SB-622B619 SB-619B626 SB-626 | B564 SB-564B366 SB-366 | AMS 5878AMS 5891AMS 5839 | – |
| Haynes 282N07208 | – | B637 | – | – | AMS 5951AMS 5915 | – |
| Nimonic | ||||||
| Nimonic 75N06075 | – | – | – | – | BS HR 5BS HR 504BS HR 203BS HR 403 | – |
| Nimonic 80AN07080 | – | B637 | – | – | BS HR 1BS HR 201BS HR 401 | – |
| Nimonic C-263N07263 | – | – | – | – | AMS 5872AMS 5886BS HR 10BS HR 206BS HR 404 | – |
| Udimet | ||||||
| Udimet 500N07500 | – | – | – | – | AMS 5751AMS 5384 | – |
| Duplex and super-austenitic | ||||||
| 254 SMOS31254 | A240 SA-240 | A479 SA-479 | A312 SA-312A249 SA-249A269A358 SA-358 | A182 SA-182 | – | – |
| Duplex 2205S32205 / S31803 | A240 SA-240 | A479 SA-479 | A790 SA-790A789 SA-789A928 SA-928 | A182 SA-182A815 SA-815 | – | – |
| Super duplex 2507S32750 | A240 SA-240 | A479 SA-479 | A790 SA-790A789 SA-789A928 SA-928 | A182 SA-182A815 SA-815 | – | – |
| Super duplex S32760S32760 | A240 SA-240 | A479 SA-479 | A790 SA-790A789 SA-789A928 SA-928 | A182 SA-182A815 SA-815 | – | – |
| 20Mo-4N08024 | B463 SB-463 | B473 SB-473 | B464 SB-464 | – | – | – |
| Titanium | ||||||
| Titanium Grade 1R50250 | B265 SB-265 | B348 SB-348 | B338 SB-338B861 SB-861B862 SB-862 | B381 SB-381B363 SB-363 | – | – |
| Titanium Grade 2R50400 | B265 SB-265 | B348 SB-348 | B338 SB-338B861 SB-861B862 SB-862 | B381 SB-381B363 SB-363 | – | – |
| Titanium Grade 5R56400 | B265 SB-265 | B348 SB-348 | B861 SB-861B862 SB-862 | B381 SB-381 | AMS 4911AMS 4928AMS 4965 | – |
| Titanium Grade 7R52400 | B265 SB-265 | B348 SB-348 | B338 SB-338B861 SB-861B862 SB-862 | B381 SB-381B363 SB-363 | – | – |
| Titanium Grade 11R52250 | B265 SB-265 | B348 SB-348 | B338 SB-338B861 SB-861B862 SB-862 | B381 SB-381B363 SB-363 | – | – |
| Ni-Resist | ||||||
| Ni-Resist Type 1F41000 | – | – | – | – | – | A436EN 13835 |
| Ni-Resist Type 2F41002 | – | – | – | – | – | A436EN 13835 |
| Ni-Resist Type 5F41006 | – | – | – | – | – | A436EN 13835 |
What a Standard Does Not Tell You
A specification sets limits, not an exact analysis. Two heats of B443 plate can differ by a few tenths of a per cent in chromium and molybdenum and both pass. Specifications are also revised, so the year suffix on a marking (B443-19, for example) matters when you check an old certificate against a current limit. And a marking only proves what the piece was made to, not that it is still that material: a weld overlay, a coating or a repair can change what is actually there. That is why markings are normally confirmed with PMI.
FAQ
What standard is Inconel 625 pipe made to?
Seamless Inconel 625 pipe and tube is made to ASTM B444 (ASME SB-444) and welded pipe to ASTM B705. The grade is UNS N06625 in both.
Is ASME SB-443 the same as ASTM B443?
ASME adopts the ASTM specification into the Boiler and Pressure Vessel Code, Section II Part B. The text is identical or carries additional ASME requirements, so material is often certified to both, as “ASTM B443 / ASME SB-443”.
Does a spec number identify the alloy?
No. The specification number describes the product form and its requirements. The UNS number, such as N06625, identifies the alloy. One alloy appears in many specifications.
Can scrap be certified to an ASTM standard?
No. Standards apply to new products. Scrap is described by the grade it was made to, backed by markings, mill certificates and a PMI record.