ASTM B168/B168M covers rolled plates, sheets, and strips made of nickel-chromium-iron alloys for general corrosion-resisting and high-temperature service. Two specification systems: B168 (Inch-Pound) and B168M (SI/Metric).
| Attribute |
Detail |
| Latest Edition |
B168-19e01 (reapproved 2024) |
| UNS Alloys |
N06600, N06601, N06603, N06690, N06693, N06025, N06045, N06696 |
| Product Forms |
Plate, Sheet, Strip |
| Heat Treatment |
Solution Annealed (standard) |
| ASME Code |
SB-168 / SB-168M (ASME Section II Part B) |
2. UNS Alloys Covered by ASTM B168
| UNS No. |
Alloy Name |
Ni % |
Cr % |
Key Features |
| N06600 |
Inconel 600 |
72 min |
14-17 |
Standard Ni-Cr-Fe, excellent oxidation |
| N06601 |
Inconel 601 |
58-63 |
21-25 |
+Al for oxidation/carburization resistance |
| N06603 |
Alloy 603 |
58-63 |
21-25 |
Enhanced oxidation resistance |
| N06690 |
Inconel 690 |
58 min |
27-31 |
High-Cr for nitric acid, nuclear |
| N06693 |
Alloy 693 |
57-63 |
27-31 |
+Al, Nb for high-temp strength |
| N06025 |
Alloy 602CA |
Rem. |
24-26 |
+Al, Y for extreme temps |
| N06045 |
Alloy 45TM |
45-50 |
26-29 |
Carbon control, carburization resist |
| N06696 |
Alloy 696 |
57-63 |
28-31 |
+W for creep resistance |
3. Chemical Composition Requirements (Table 1)
| UNS |
Ni+Co |
Cr |
Fe |
Al |
Ti |
C |
Mn |
Si |
| N06600 |
72.0 min |
14-17 |
6-10 |
— |
— |
0.15 |
1.0 |
0.5 |
| N06601 |
58-63 |
21-25 |
Rest |
1.0-1.7 |
— |
0.10 |
1.0 |
0.5 |
| N06690 |
58 min |
27-31 |
7-11 |
— |
— |
0.05 |
0.5 |
0.5 |
| N06025 |
Rest |
24-26 |
8-11 |
1.8-2.4 |
0.1-0.2 |
0.15-0.25 |
0.15 |
0.5 |
| N06045 |
45-50 |
26-29 |
21-25 |
— |
— |
0.05 |
0.5 |
0.5 |
4. Mechanical Property Requirements (Tables 2-5)
| UNS |
Temper |
Tensile min |
Yield min |
Elong. % |
Notes |
| N06600 |
Annealed |
75 ksi |
30 ksi |
30 |
Plate/Sheet |
| Cold Worked |
85 ksi |
50 ksi |
15 |
Higher strength |
| N06601 |
Annealed |
80 ksi |
30 ksi |
30 |
Standard |
| Cold Worked |
100 ksi |
60 ksi |
15 |
High strength |
| N06690 |
Annealed |
78 ksi |
30 ksi |
30 |
Nuclear grade |
| Cold Worked |
85 ksi |
45 ksi |
15 |
Higher strength |
| N06025 |
Annealed |
94 ksi |
40 ksi |
25 |
High-temp strength |
5. Heat Treatment & Surface Finish
ASTM B168 alloys are typically supplied in solution-annealed condition. Annealing temperature range: 1850-2050°F (1010-1121°C) with rapid cooling (water quench or air cool depending on section size). Stress relief may be specified for fabricated components. Standard surface finishes include hot-rolled, cold-rolled, polished, and matte finishes.
6. Testing & Inspection
| Test |
Requirement |
Standard |
| Chemical Analysis |
One per heat; all elements per Table 1 |
ASTM E1473 |
| Tensile Test |
One per lot; tensile, yield, elongation |
ASTM B906 |
| Hardness |
Per agreement |
ASTM E18 |
7. Related Standards
| Standard |
Scope |
Relation |
| ASTM B166 |
Ni-Cr-Fe alloy rod and bar |
Same alloys, rod form |
| ASTM B167 |
Ni-Cr-Fe alloy seamless pipe |
Same alloys, pipe form |
| ASTM B163 |
Ni-Cr-Fe alloy seamless tube |
Same alloys, tube form |
| ASME SB-168 |
ASME Boiler & Pressure Vessel Code |
Code adoption |
8. How to Order
| No. |
Item |
Requirement |
| 1 |
Specification |
ASTM B168 or ASME SB-168 |
| 2 |
UNS Designation |
e.g., N06600 (Inconel 600), N06601 (Inconel 601) |
| 3 |
Product Form |
Plate, Sheet, or Strip |
| 4 |
Temper / Condition |
Annealed or Cold Worked |
| 5 |
Dimensions |
Thickness x Width x Length |
| 6 |
Certification |
EN 10204 3.1 MTC |
Download ASTM B168 / B168M Standard (PDF)
The official ASTM B168-19e01 PDF is available from our HT Pipe Download Center. The document includes chemical composition Table 1 for all 8 UNS alloys, mechanical property Tables 2-5, heat treatment requirements, and dimensional tolerance references.
Go to Download Center | Request MTC / Quotation
9. Frequently Asked Questions
Q: What is the difference between Inconel 600 (N06600) and Inconel 601 (N06601)?
N06600 (Inconel 600) is a standard nickel-chromium-iron alloy with 72% minimum nickel and 14-17% chromium. It provides excellent oxidation resistance and corrosion resistance in a wide range of environments up to 2000°F (1093°C). N06601 (Inconel 601) contains 58-63% nickel, 21-25% chromium, and 1.0-1.7% aluminum — the aluminum addition creates a protective aluminum oxide layer that provides superior resistance to high-temperature oxidation and carburization. Choose N06601 for thermal processing equipment, catalyst supports, and applications requiring cyclic oxidation resistance. Choose N06600 for general chemical processing, heat exchangers, and nuclear steam generator tubing.
Q: What is Inconel 690 (N06690) used for?
N06690 (Inconel 690) is a high-chromium nickel alloy (27-31% Cr, 58% min Ni) with superior resistance to oxidizing acids, especially nitric acid, and to high-temperature oxidation. Primary applications include: nuclear steam generator tubes (where it replaced Inconel 600 due to lower cobalt activation), nitric acid production equipment, petrochemical processing, and thermal treatment furnace components. Its high chromium content provides excellent resistance to stress corrosion cracking in high-purity water environments.
Q: Can ASTM B168 nickel alloys be welded?
Yes, ASTM B168 nickel-chromium-iron alloys are readily weldable by GTAW (TIG), GMAW (MIG), and SMAW (stick) processes. Use matching filler metals: ERNiCr-3 (AWS A5.14) for N06600/N06690, ERNiCrCoMo-1 for N06601, and ERNiCrFe-11 for N06025. Pre-heat is not required. Post-weld heat treatment is generally not required for these solution-annealed alloys. Control heat input to minimize distortion and maintain the corrosion-resistant microstructure.
Q: What is the maximum service temperature for ASTM B168 alloys?
Maximum service temperature depends on the specific alloy and environment: N06600 (Inconel 600) — up to 2000°F (1093°C) in oxidizing atmospheres; N06601 (Inconel 601) — up to 2200°F (1204°C) for continuous service due to its aluminum addition; N06690 (Inconel 690) — up to 1900°F (1038°C); N06025 (Alloy 602CA) — up to 2300°F (1260°C) in reducing atmospheres. In reducing or sulfiding atmospheres, maximum temperatures may be significantly lower. Always verify the specific service environment with the material supplier.
Q: What corrosion resistance does N06600 offer?
N06600 (Inconel 600) offers excellent corrosion resistance in: organic acids (acetic, fatty, phosphoric) at moderate temperatures; alkaline solutions (caustic soda, sodium hydroxide); neutral and acidic salt solutions; fresh and seawater (excellent stress corrosion cracking resistance); and oxidizing atmospheres. It has poor resistance in strongly oxidizing acids (nitric acid at high concentrations). Its high nickel content provides exceptional resistance to chloride-ion stress corrosion cracking, making it ideal for seawater-cooled heat exchangers and chloride-containing process streams.
Q: What are the high-temperature alloys in ASTM B168?
The high-temperature alloys in ASTM B168 include: N06025 (Alloy 602CA) with aluminum and yttrium additions for extreme temperature oxidation resistance up to 2300°F; N06045 (Alloy 45TM) with controlled carbon for carburization resistance; N06696 (Alloy 696) with tungsten addition for enhanced creep rupture strength; and N06693 (Alloy 693) with niobium for high-temperature strength. These alloys are selected for furnace components, radiant tubes, recuperators, and high-temperature processing equipment where creep strength and oxidation resistance are critical.
Request a Quote — ASTM B168 Nickel-Chromium-Iron Alloy Plate
Zhengzhou Huitong (HT PIPE) supplies ASTM B168 / SB-168 compliant nickel-chromium-iron alloy plate, sheet, and strip in all standard UNS alloys (N06600, N06601, N06690, N06025) with full EN 10204 3.1 Mill Test Certificates. Solution-annealed condition. Available in various thicknesses and surface finishes.
