Author: RAS Thermal Applications Team · Updated 2026-10-10
TL;DR The grade name travels; the standard does not. These twelve cover ASTM, AMS, EN, DIN, GB and JIS bolting and bar stock.
Global procurement of superalloy fasteners means navigating several standards systems at once. The same Inconel 718 bolt may be specified as ASTM B637 in the United States, EN 10269 2.4668 in Europe, GH4169 under GB/T 3098.8 in China, or NW7718 per JIS in Japan.
The table below lists the twelve bolting and bar standards that sit behind the grades we stock, with the grades each governs and the region it is written for.
| Standard | Title | Grades covered | Region | Notes |
|---|---|---|---|---|
| ASTM A193 | Alloy-steel and stainless steel bolting for high temperature | B8 (304), B8M (316), B16 (Cr-Mo-V) | USA / global | The primary high-temperature bolting standard for non-nickel alloys. Nickel alloy bolting is covered by separate ASTM standards such as B637. |
| ASTM A194 | Carbon and alloy steel nuts for high-pressure and high-temperature service | Grade 8, 8M, 2H, 7 | USA / global | Companion nut standard to A193. Nickel alloy nuts sit under ASTM B637, B574 and similar. |
| ASTM B637 | Precipitation-hardened nickel alloy bars, forgings and forging stock | UNS N07718 (Inconel 718) | USA / global | The primary standard for Inconel 718 bolting material. Covers solution-treated and aged conditions for high-temperature service. |
| ASTM B574 | Low-carbon nickel-molybdenum-chromium alloy rod | UNS N10276 (Hastelloy C-276) | USA / global | The standard for Hastelloy C-276 bar stock. Solid-solution alloy, specified in the annealed condition. |
| ASTM B446 | Nickel-chromium-molybdenum-columbium alloy (UNS N06625) bar | UNS N06625 (Inconel 625) | USA / global | Grade 1 (annealed) and Grade 2 (solution-annealed). Grade 2 for creep service above 600 °C. |
| ASTM B865 | Precipitation-hardenable nickel-copper-aluminium alloy bar | UNS N05500 (Monel K-500) | USA / global | Age-hardened condition with hardness limits. QQ-N-286 is the superseded US Federal equivalent. |
| AMS 5662 / 5663 | Nickel alloy, corrosion and heat resistant, bars, forgings and rings 52.5Ni-19Cr-3.0Mo-5.1Cb-0.90Ti-0.50Al | Inconel 718 (UNS N07718) | Aerospace | Aerospace-grade 718. AMS 5663 adds tighter ageing and higher minimum properties for rotating hardware. |
| AMS 5731 / 5732 / 5734 | Iron-nickel alloy bars and forgings, 15Cr-25.5Ni-1.2Mo-2.1Ti-0.006B | A-286 (UNS S66286) | Aerospace | 5731 solution treated, 5732 solution and aged, 5734 high-strength aged. The aerospace equivalent to ASTM A453. |
| EN 10269 | Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties | 1.4980 (A-286), 2.4668 (718), 2.4856 (625) | EU | The European harmonised standard covering both steel and nickel alloy bolting grades. References EN 10204 for certification. |
| DIN 267-13 | Fasteners: technical delivery conditions for high and low temperature service | Multiple | Germany / EU | German technical delivery conditions, often referenced together with EN 10269. Covers complete fastener specification including dimensions. |
| GB/T 3098.8 | Mechanical properties of fasteners for high-temperature service | Multiple | China | The Chinese national standard for high-temperature fastener mechanical properties. References GB material standards for specific grades. |
| JIS B 1180 | Hexagon bolts and hexagon nuts | Multiple | Japan | The Japanese Industrial Standard for hex bolts and nuts. Material grade dimensions and mechanical properties follow JIS G 4107 for alloy steel and JIS G 4901 for nickel alloys. |
How to work through this topic
- 01 Name the standard and the UNS number together. Write both on the purchase order. A trade name alone, such as Inconel, invites substitution with generic material that does not meet the same chemistry or mechanical requirements.
- 02 Check what the standard actually covers. ASTM A193 covers alloy steel and stainless bolting, not nickel alloys; nickel alloy bolting sits under separate standards such as B637, B574 and B446. Naming the wrong family is the most common source of non-conforming supply.
- 03 Match the condition, not just the grade. The same grade is supplied solution treated, solution-and-aged, or high-strength aged, and the AMS and A453 class numbers are not interchangeable. Put the condition and the hardness limit on the line item.
- 04 State the certificate grade. EN 10204 3.1 is our standard certificate; 3.2 adds an independent witness. Nuclear, aerospace, subsea and NORSOK scopes generally require the witnessed grade, so raise it before the order is placed.
Frequently Asked Questions
Can a bolt certified to ASTM B637 be supplied against EN 10269?
The grades overlap, the documents do not. EN 10269 covers 2.4668 (Inconel 718) as a European harmonised standard and references EN 10204 for certification, so a material that is chemically and mechanically equivalent still needs the certificate re-issued to the standard named on the order.
Which standard covers high-temperature bolting for non-nickel alloys?
ASTM A193 for the bolts and ASTM A194 for the companion nuts. Nickel alloy bolting is not covered by A193 at all: it is covered by separate standards such as ASTM B637 for Inconel 718 and ASTM B574 for Hastelloy C-276.
What is the difference between ASTM A453 and AMS 5731 series for A-286?
ASTM A453 Grade 660 is the industrial bolting standard for A-286, with Classes A to D differing in heat treatment and hardness. The AMS 5731, 5732 and 5734 series is the aerospace equivalent, split into solution-treated, solution-and-aged, and high-strength aged conditions.
Do Chinese and Japanese standards map cleanly onto the ASTM grades?
The chemistry maps closely enough to specify against, but the acceptance limits and the certificate wording are written independently. GB/T 3098.8 covers the mechanical properties of high-temperature fasteners in China and JIS B 1180 covers hex bolts and nuts in Japan, each referencing its own material standards.
Bottom line: The same Inconel 718 bolt is specified as ASTM B637 in the United States, EN 10269 2.4668 in Europe, GH4169 under GB/T 3098.8 in China and NW7718 under JIS in Japan. Name the standard, the UNS number and the condition together, and the ambiguity disappears.