ASTM B166 is the standard specification by ASTM International covering nickel-chromium-iron alloys in the form of hot-finished and cold-drawn rod, bar, and shapes. The most widely used grade is UNS N06600 (Alloy 600 / Inconel 600). Other important grades include UNS N06601 (Alloy 601) and UNS N06690 (Alloy 690). The companion specification ASME SB-166 adopts identical requirements.
Zhengzhou Huitong (HT Pipe) supplies ASTM B166 / SB-166 compliant nickel-chromium-iron alloy rods and bars with full Mill Test Certificates (MTC) per EN 10204 3.1.
1. Standard Scope & Designation
ASTM B166 covers the following nickel-chromium-iron grades:
| UNS No. |
Common Name |
Alloy Type |
Key Features & Application |
| UNS N06600 |
Alloy 600 / Inconel 600 |
Ni-72% min, Cr-14-17%, Fe-6-10%, C-0.15% max |
General high-temp — furnaces, chemical, nuclear |
| UNS N06601 |
Alloy 601 / Inconel 601 |
Ni-58-63%, Cr-21-25%, Fe-max balance, Al-1.0-1.7% |
Oxidation resistance to 1204°C |
| UNS N06690 |
Alloy 690 / Inconel 690 |
Ni-58% min, Cr-27-31%, Fe-7-11%, C-0.05% max |
Nuclear steam generators, SCC resistance |
| UNS N06025 |
Alloy 602CA |
Ni-60-65%, Cr-24-27%, Al-1.8-2.4%, Y 0.05-0.12% |
Extreme temperature oxidation to 1204°C |
| UNS N06045 |
Alloy 45TM |
Ni-48-55%, Cr-26-29%, Fe-10-15%, Mo-2.5-4.0% |
Waste incineration, molten salt |
Scope Statement: "This specification covers nickel-chromium-iron alloys (UNS N06600, N06601, N06690, N06603, N06693, N06025, N06045, and N06696) in the form of hot-finished and cold-drawn rounds, squares, hexagons, and rectangles for high-temperature and corrosive service."
| Designation |
Issuing Body |
Unit System |
Latest Edition |
| ASTM B166 |
ASTM International |
Inch-Pound |
B166-22 |
| ASME SB-166 |
ASME (BPVC Sec. II Part B) |
Both |
2025 Edition |
2. Alloy Grades Covered by ASTM B166
ASTM B166 covers nickel-chromium-iron alloys designed for high-temperature strength and corrosion resistance:
| UNS No. |
Commercial Designation |
Alloy Type |
Key Features & Typical Application |
| UNS N06600 |
Alloy 600 / Inconel 600 |
Ni-72% min, Cr-14-17%, Fe-6-10%, C-0.15% max |
General high-temp — furnaces, chemical, nuclear |
| UNS N06601 |
Alloy 601 / Inconel 601 |
Ni-58-63%, Cr-21-25%, Fe-max balance, Al-1.0-1.7% |
Oxidation resistance to 1204°C |
| UNS N06690 |
Alloy 690 / Inconel 690 |
Ni-58% min, Cr-27-31%, Fe-7-11%, C-0.05% max |
Nuclear steam generators, SCC resistance |
| UNS N06025 |
Alloy 602CA |
Ni-60-65%, Cr-24-27%, Al-1.8-2.4%, Y 0.05-0.12% |
Extreme temperature oxidation to 1204°C |
| UNS N06045 |
Alloy 45TM |
Ni-48-55%, Cr-26-29%, Fe-10-15%, Mo-2.5-4.0% |
Waste incineration, molten salt |
3. Chemical Composition — Key Grades (ASTM B166)
Values are maximum unless shown as a range. Heat analysis per ASTM B166.
| Grade |
Ni% |
Cr% |
Fe% |
Al% |
C% |
Mn% |
Cu% |
Si% |
| N06600 |
72.0 min |
14.0–17.0 |
6.0–10.0 |
— |
0.15 |
1.00 |
0.50 |
0.50 |
| N06601 |
58.0–63.0 |
21.0–25.0 |
Balance |
1.0–1.7 |
0.10 |
1.00 |
1.00 |
0.50 |
| N06690 |
58.0 min |
27.0–31.0 |
7.0–11.0 |
— |
0.05 |
0.50 |
0.50 |
0.50 |
Note: Product analysis tolerances per ASTM B166 apply.
4. Mechanical Property Requirements (ASTM B166)
All values are minimum requirements unless otherwise stated. Tensile testing per ASTM E8.
| Grade |
UNS |
Tensile Strength
min MPa (ksi) |
Yield Strength 0.2%
min MPa (ksi) |
Elong.
min % |
Hardness
max |
| Alloy 600 |
N06600 |
552 (80) |
241 (35) |
30 |
184 HB |
Annealed |
| Alloy 601 |
N06601 |
586 (85) |
207 (30) |
30 |
192 HB |
Annealed |
| Alloy 690 |
N06690 |
483 (70) |
172 (25) |
35 |
184 HB |
Solution Annealed |
Note: Hardness testing per ASTM E10 (Brinell) or ASTM E18 (Rockwell). Cold-worked bar may exhibit higher strength due to cold work.
5. Heat Treatment Requirements
| Grade |
Condition |
Heat Treatment |
Cooling |
| UNS N06600 (Alloy 600) |
Annealed |
871–982°C (1600–1800°F) |
Water quench or rapid air cool |
| UNS N06601 (Alloy 601) |
Annealed |
1040–1150°C (1900–2100°F) |
Water quench or rapid air cool |
| UNS N06690 (Alloy 690) |
Solution Annealed |
1010–1066°C (1850–1950°F) |
Water quench |
Important: Alloy 600 is a solid-solution alloy that combines chromium for oxidation resistance with nickel for basic corrosion resistance. Alloy 601 adds aluminum to form a tightly adherent alumina scale for exceptional oxidation resistance up to 2200°F (1204°C). Alloy 690 uses high chromium (27–31%) and low carbon for exceptional resistance to stress corrosion cracking in high-purity water, making it the preferred alloy for nuclear steam generator tubing.
6. Testing & Inspection Requirements
| Test |
Requirement |
Reference Standard |
| Chemical Analysis (Heat) |
One per heat / melt; all elements per Table 1 |
ASTM E1473 / E354 |
| Tensile Test |
One per lot (same heat, same condition, same diameter group) |
ASTM E8 / E8M |
| Hardness Test |
Brinell or Rockwell; one per lot |
ASTM E10 / E18 |
| Intergranular Corrosion |
Supplementary requirement when specified |
ASTM G28 |
| Visual & Dimensional |
Surface condition, straightness, diameter tolerance |
ASTM B166 Tables |
| PMI (Positive Material ID) |
When specified by purchaser |
ASTM E1473 |
7. Rod & Bar Dimensions — Available Sizes
ASTM B166 covers various rod and bar forms. Common commercial size ranges:
| Form |
Diameter / Width |
Typical Length |
Tolerance |
| Hot-Finished Round |
12.7 – 200 mm (1/2–8 in.) |
3.0 – 6.0 m random |
±0.13 mm typical |
| Cold-Drawn Round |
6.35 – 100 mm (1/4–4 in.) |
3.0 – 6.0 m random |
±0.05 mm typical |
| Hot-Finished Square |
12.7 – 150 mm |
3.0 – 6.0 m random |
±0.25 mm typical |
| Hot-Finished Hexagon |
12.7 – 100 mm (AF) |
3.0 – 6.0 m random |
±0.25 mm typical |
Note: Diameter tolerances per ASTM B166 tables. Cut-to-length available on request.
8. Industries & Applications
| Industry |
Recommended Grades |
Typical Applications |
| Nuclear Industry |
N06600, N06690 |
Steam generator tubing, reactor internals, control rod components |
| Chemical Processing |
N06600 |
Furnace components, baskets, retorts, reformer tubing |
| Aerospace |
N06600, N06601 |
Aircraft engine exhaust systems, turbine seals, afterburner components |
| Heat Treatment |
N06600, N06601 |
Radiant tubes, furnace belts, muffle liners, burner nozzles |
| Power Generation |
N06600, N06690 |
Superheater tubes, boiler components, steam piping |
| Industrial Heaters |
N06601, N06025 |
High-temperature furnace components, catalytic grids |
9. B166 vs B168 vs B167 — Ni-Cr-Fe Alloy Specifications Compared
| Criteria |
ASTM B166 |
ASTM B168 |
ASTM B167 |
| Product Form |
Rod, Bar, Shapes |
Plate, Sheet, Strip |
Seamless Pipe & Tube |
| Processing |
Hot-finished, Cold-drawn |
Hot-rolled, Cold-rolled |
Hot-finished, Cold-drawn |
| Key Grades |
N06600, N06601, N06690, N06025 |
N06600, N06601, N06690 |
N06600, N06601, N06690 |
| Mechanical Props |
TS≥552 MPa, YS≥241 MPa (N06600) |
TS≥552 MPa, YS≥241 MPa (N06600) |
TS≥552 MPa, YS≥241 MPa (N06600) |
| Max Service Temp |
N06601: 1204°C |
N06601: 1204°C |
N06601: 1204°C |
| Primary Use |
Machined parts, fasteners, shafts |
Pressure vessels, structural panels |
Process piping, heat exchanger tubes |
Key Distinction: ASTM B166, B168, and B167 form a complementary family of specifications for Alloy 600-type materials across all product forms. B166 covers rod/bar/shapes (solid long products), B168 covers flat products (plate, sheet, strip), and B167 covers tubular products (seamless pipe and tube). All share the same UNS grades and similar chemical/mechanical requirements.
10. Related Standards
| Standard |
Scope |
Relationship |
| ASTM B168 |
Ni-Cr-Fe Alloy Plate, Sheet, Strip |
Flat product companion specification |
| ASTM B167 |
Ni-Cr-Fe Alloy Seamless Pipe & Tube |
Tubular product companion specification |
| ASTM B880 |
General Requirements for Nickel Alloys |
Governs tolerances, testing, certification |
| ASTM E8 / E8M |
Tension Testing of Metallic Materials |
Tensile test method required by B166 |
| ASTM E1473 |
Chemical Analysis of Ni & Ni Alloys |
Chemical analysis method |
| ASTM G28 |
Intergranular Corrosion Testing for Ni Alloys |
Supplementary requirement |
| ASME SB-166 |
BPVC Section II Part B |
ASME adoption with CMTR |
| DIN EN 10204 |
Metallic Products — Inspection Documents |
3.1 CMTR certification |
11. How to Order — Required Information
| No. |
Item |
Requirement / Example |
| 1 |
Specification |
ASTM B166 / ASME SB166 |
| 2 |
Grade / UNS |
e.g., UNS N06600 (Alloy 600) or UNS N06690 (Alloy 690) |
| 3 |
Shape |
Round, Square, Hexagon, Rectangle |
| 4 |
Processing |
Hot-finished (HF) or Cold-drawn (CD) |
| 5 |
Diameter / Size |
e.g., 50 mm round |
| 6 |
Length |
Random (RL ~3–6 m) or Cut-to-length |
| 7 |
Condition |
Annealed (default) or Solution Annealed (690) |
| 8 |
Supplementary Tests |
PMI, intergranular corrosion, UT, impact testing |
| 9 |
Certification |
EN 10204 3.1 Certified Mill Test Report |
| 10 |
Quantity |
Pieces or total weight (kg / metric tons) |
12. Frequently Asked Questions
Q: What is ASTM B166 nickel-chromium-iron alloy rod?
ASTM B166 is the standard specification for nickel-chromium-iron alloys in the form of hot-finished and cold-drawn rod, bar, and shapes. It covers UNS N06600 (Alloy 600/Inconel 600), UNS N06601 (Alloy 601), UNS N06690 (Alloy 690), UNS N06025 (Alloy 602CA), and UNS N06045 (Alloy 45TM).
Q: What is Alloy 600 (UNS N06600 / Inconel 600)?
Alloy 600 (UNS N06600) is a nickel-chromium-iron alloy with excellent resistance to oxidation and corrosion at high temperatures. It has good resistance to dry chlorine and hydrogen chloride at elevated temperatures. Its standard composition includes approximately 72% Ni, 15% Cr, and 8% Fe.
Q: What are the mechanical properties of Alloy 600 rod per ASTM B166?
In the annealed condition, UNS N06600 rod and bar must meet: minimum tensile strength 552 MPa (80 ksi), minimum yield strength 241 MPa (35 ksi), and minimum elongation 30%. Hardness maximum is 184 HB.
Q: What is the difference between Alloy 600, 601, and 690?
Alloy 600 (N06600) is the base grade with 14–17% Cr for general high-temperature service. Alloy 601 (N06601) adds 1.0–1.7% Al for exceptional oxidation resistance up to 1204°C through alumina scale formation. Alloy 690 (N06690) has high chromium (27–31%) with low carbon for outstanding stress corrosion cracking resistance in nuclear water environments.
Q: What is the difference between ASTM B166 and ASTM B168?
ASTM B166 covers nickel-chromium-iron alloy rod, bar, and shapes. ASTM B168 covers the same alloy family in plate, sheet, and strip form. Both share the same UNS grades and similar chemical and mechanical requirements.
Q: Is ASTM B166 the same as ASME SB-166?
Technically identical in chemistry and mechanical properties. ASME SB-166 is ASTM B166 adopted into ASME BPVC Section II Part B. SB-166 additionally requires Certified Material Test Reports (CMTR) with full traceability for ASME Code-stamped equipment. Most mills supply dual-certified B166/SB-166 material.
Request a Quote — ASTM B166 Ni-Cr-Fe Alloy Rod & Bar
Zhengzhou Huitong (HT Pipe) supplies ASTM B166 / SB-166 compliant nickel-chromium-iron alloy rods and bars in UNS N06600 (Alloy 600), N06601 (Alloy 601), N06690 (Alloy 690), and other grades. Full EN 10204 3.1 CMTRs and competitive lead times from affiliated mills.
