ASTM B575/B575M is the primary standard by ASTM International covering low-carbon nickel-chromium-molybdenum alloy plate, sheet, and strip — including industry benchmarks Alloy C-276 (UNS N10276), Alloy C-22 (UNS N06022), Alloy C-4 (UNS N06455), and Alloy 59 (UNS N06059). These Ni-Cr-Mo-W alloys provide the highest level of corrosion resistance available in wrought nickel alloys — resisting pitting, crevice corrosion, and stress corrosion cracking in oxidizing and reducing acids up to boiling point. The companion specification ASME SB575 is adopted for ASME Code-stamped pressure equipment.
Zhengzhou Huitong (HT Pipe) supplies ASTM B575 / ASME SB575 compliant plate, sheet & strip with full Mill Test Certificates (MTC) per EN 10204 3.1.
1. Standard Scope & Designation
ASTM B575/B575M is the comprehensive specification covering low-carbon nickel-chromium-molybdenum alloys (UNS N10276, N06022, N06455, N06059, N06200, and others) in plate, sheet, and strip form. These alloys — commonly known as Hastelloy® C-276, C-22, C-4, and Alloy 59 — deliver exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in the most aggressive chemical environments.
| Form |
Manufacturing Process |
Size Range |
Typical Thickness/Tolerance |
| Plate / Sheet / Strip |
Hot-rolled or cold-rolled per standard; solution-annealed and quenched |
ASTM B575 covers plate, sheet, and strip from thin foil (0.005 in / 0.13 mm) to heavy plate up to 4 in (100 mm). Standard widths: 48–96 in (1220–2440 mm). Thicker plate available in hot-rolled condition; thin gauge in cold-rolled sheet/strip. |
Per standard / purchaser agreement |
Scope Statement (ASTM B575/B575M): "This specification covers plate, sheet, and strip of low-carbon nickel-chromium-molybdenum alloys (UNS N10276, N06022, N06455, N06059, N06200) for use in general corrosive service and for applications requiring resistance to pitting, crevice corrosion, and stress corrosion cracking."
| Designation |
Issuing Body |
Unit System |
Dimension Standard |
Latest Edition |
| ASTM B575 |
ASTM International |
Inch-Pound |
ASTM A480/A480M |
B575/B575M-23 |
| ASTM B575M |
ASTM International |
SI (Metric) |
ASTM A480/A480M |
B575/B575M-23 |
| ASME SB575 |
ASME (BPVC Sec. II Part B) |
Both |
ASTM A480/A480M |
2023 Edition |
2. Grades Covered by ASTM B575
ASTM B575 covers the following grades. Each grade is defined by its UNS number and specific chemistry targeted at different service environments.
| Grade / UNS |
Key Chemistry Requirements |
Mechanical Properties (min) |
| C-276 (N10276) |
Ni 51 min, Cr 14.5–16.5, Mo 15.0–17.0, W 3.0–4.5, Fe 4.0–7.0, C 0.01 max |
Annealed: TS ≥ 690 MPa (100 ksi), YS ≥ 283 MPa (41 ksi), El ≥ 40% |
| C-22 (N06022) |
Ni 51 min, Cr 20.0–22.5, Mo 12.5–14.5, W 2.5–3.5, Fe 2.0–6.0, C 0.015 max |
Annealed: TS ≥ 690 MPa (100 ksi), YS ≥ 310 MPa (45 ksi), El ≥ 45% |
| C-4 (N06455) |
Ni 65 min, Cr 14.0–18.0, Mo 14.0–17.0, Fe 3.0 max, C 0.015 max |
Annealed: TS ≥ 690 MPa (100 ksi), YS ≥ 276 MPa (40 ksi), El ≥ 40% |
| Alloy 59 (N06059) |
Ni bal, Cr 22.0–24.0, Mo 15.0–16.5, Fe 1.5 max, C 0.010 max |
Annealed: TS ≥ 690 MPa (100 ksi), YS ≥ 310 MPa (45 ksi), El ≥ 45% |
3. Chemical Composition
Values are weight percent maximum unless shown as a range. Heat analysis. Per ASTM B575 Table 1.
| Ni |
Cr |
Mo |
W |
Fe |
C |
Mn |
Si |
V |
Co |
PREN |
Notes |
| Ni |
Balance (51 min) |
Balance (51 min) |
65 min |
Balance (59 min) |
Primary alloy base |
— |
| Cr |
14.5–16.5 |
20.0–22.5 |
14.0–18.0 |
22.0–24.0 |
Corrosion resistance |
— |
| Mo |
15.0–17.0 |
12.5–14.5 |
14.0–17.0 |
15.0–16.5 |
Pitting & crevice resistance |
— |
| W |
3.0–4.5 |
2.5–3.5 |
— |
— |
Enhances corrosion resistance |
— |
| Fe |
4.0–7.0 |
2.0–6.0 |
3.0 max |
1.5 max |
— |
— |
| C |
0.01 max |
0.015 max |
0.015 max |
0.010 max |
Ultra-low carbon for IGC resistance |
— |
| Mn |
1.0 max |
0.5 max |
1.0 max |
0.5 max |
— |
— |
| Si |
0.08 max |
0.08 max |
0.08 max |
0.10 max |
— |
— |
| V |
0.35 max |
0.35 max |
— |
— |
— |
— |
| Co |
2.5 max |
2.5 max |
2.0 max |
0.3 max |
— |
— |
| PREN* |
~64 |
~64 |
~60 |
~72 |
* = %Cr + 3.3×%Mo (approx.) |
— |
4. Mechanical Property Requirements
All values are minimum requirements. Tensile testing per ASTM E8/E8M.
| Grade / Condition |
Heat Treatment |
TS min MPa (ksi) |
YS min MPa (ksi) |
El min (%) |
| C-276 (N10276) |
Solution Annealed |
690 (100) |
283 (41) |
40 |
| C-22 (N06022) |
Solution Annealed |
690 (100) |
310 (45) |
45 |
| C-4 (N06455) |
Solution Annealed |
690 (100) |
276 (40) |
40 |
| Alloy 59 (N06059) |
Solution Annealed |
690 (100) |
310 (45) |
45 |
| C-2000 (N06200) |
Solution Annealed |
690 (100) |
283 (41) |
45 |
5. Heat Treatment Requirements
| Grade |
Temperature Range |
Cooling Method |
Purpose |
| C-276 |
1120–1160°C (2050–2120°F) |
Rapid water quench or air cool |
Prevents precipitation of detrimental intermetallic phases |
| C-22 |
1120–1160°C (2050–2120°F) |
Rapid water quench or air cool |
Rapid cooling essential; minimizes sigma/M6C precipitation |
| C-4 |
1065–1140°C (1950–2085°F) |
Rapid water quench |
Superior thermal stability — less susceptible to intermetallic precipitation |
| Alloy 59 |
1100–1180°C (2010–2160°F) |
Rapid water quench |
Highest PREN grade; rapid quench maximizes pitting resistance |
6. Testing & Inspection Requirements
| Test |
Requirement |
Reference Standard |
| Chemical Analysis (Heat) |
One per heat; all elements per ASTM B575 Table 1 |
ASTM B575 Table 1 |
| Tensile Test |
One per lot; tensile per ASTM E8/E8M |
ASTM E8 / E8M |
| Hardness Test |
Rockwell B or Brinell per agreement |
ASTM E18 / E10 |
| Corrosion Test (optional) |
ASTM G28 Method A (ferric sulfate) or B (mixed acid) for intergranular attack verification |
ASTM G28 |
| Ultrasonic |
Per ASTM A578 or per agreement |
ASTM A578/A578M |
| Visual & Dimensional |
Thickness tolerance per ASTM A480; flatness per agreement |
ASTM B575 / A480 |
7. Dimensions & Dimensional Tolerances
ASTM B575 covers plate, sheet, and strip from thin foil (0.005 in / 0.13 mm) to heavy plate up to 4 in (100 mm). Standard widths: 48–96 in (1220–2440 mm). Thicker plate available in hot-rolled condition; thin gauge in cold-rolled sheet/strip. Mill certified to minimum and maximum thickness tolerances per ASTM A480.
8. Industries & Applications
| Industry |
Recommended Grade |
Typical Service Media / Application |
| Chemical Processing |
C-276 / C-22 |
Reactors, heat exchangers, piping for mixed acids, chlorinated solvents |
| Pollution Control |
C-276 / C-59 |
FGD scrubbers, stack liners, ducting for wet flue gas |
| Pulp & Paper |
C-276 / C-22 |
Bleach plant washers, chlorine dioxide generators |
| Marine / Offshore |
C-276 |
Seawater-cooled exchangers, subsea components with crevice exposure |
| Pharmaceutical |
C-22 |
Reaction vessels, clean piping for aggressive media |
| Waste Treatment |
C-276 |
Hazardous waste incinerator scrubbers, evaporators |
9. ASTM B575 vs ASTM B333 (Ni-Mo Alloy Plate — Alloy B-2/B-3) — Comparison
| Standard |
ASTM B575 (C-type: Cr-Mo) |
ASTM B333 (B-type: Mo-only) |
| Principal Alloys |
C-276, C-22, C-4, Alloy 59 |
B-2 (N10665), B-3 (N10675) |
| Cr Content |
14.5–24.0% (high Cr) |
≤ 1.0% (essentially Cr-free) |
| Best Environment |
Oxidizing + reducing acids, chlorides |
Pure reducing acids (HCl without oxidizers) |
| Oxidizer Tolerance |
Excellent (high Cr enables passive film) |
Very poor — intolerance to any oxidizers |
| Key Limitation |
None for most mixed acid service |
Cannot tolerate ferric/copper ions in HCl |
| PREN Range |
60–72 |
N/A (no significant Cr for PREN) |
Key Distinction: ASTM B575 C-type alloys (C-276, C-22, C-4) are the universal choice for mixed oxidizing-reducing acid environments, including chlorides. ASTM B333 B-type alloys (B-2, B-3) are hyper-specialized for pure reducing acids (HCl, H₂SO₄) and fail rapidly in the presence of any oxidizers. For most chemical processing applications, B575 alloys are safer and more versatile.
10. Related Standards
| Standard |
Scope |
Relationship |
| ASTM B622 |
Ni-Cr-Mo Alloy Seamless Pipe & Tube (C-276, C-22, etc.) |
Tubular complement to B575 plate for same alloys |
| ASTM B619 |
Ni-Cr-Mo Alloy Welded Pipe (C-276, C-22) |
Welded pipe in same alloys |
| ASTM B574 |
Ni-Cr-Mo Alloy Rod and Bar |
Bar stock for machined components |
| ASME SB575 |
ASME BPVC Section II Part B |
Identical; code-stamped equipment |
| ASTM G28 |
Detecting Susceptibility to Intergranular Corrosion |
Method A (ferric sulfate) and Method B (mixed acid) |
| ASTM A262 |
Detecting IGC in Stainless Steels |
Not applicable; use G28 for Ni alloys |
| ASTM B333 |
Ni-Mo Alloy Plate (B-2, B-3 — UNS N10665/N10675) |
Mo-only alloys for pure reducing acid service |
| NACE MR0175/ISO 15156 |
SSC Resistant Materials for Oil & Gas |
C-276 and C-22 are acceptable for severe sour service |
11. How to Order — Required Information
| No. |
Item |
Requirement / Example |
| 1 |
Specification |
ASTM B575 / ASME SB575 |
| 2 |
Grade / UNS |
N10276 (C-276), N06022 (C-22), N06455 (C-4), N06059 (Alloy 59), etc. |
| 3 |
Product Form |
Plate, Sheet, or Strip |
| 4 |
Dimensions |
Thickness × Width × Length (or coil width for strip) |
| 5 |
Condition |
Solution-annealed and quenched (mandatory) |
| 6 |
Surface Finish |
No. 1 (HRAP), No. 2D, No. 2B, or pickled finish |
| 7 |
Corrosion Test (optional) |
ASTM G28 Method A or B per agreement |
| 8 |
Certification |
EN 10204 3.1 or 3.2 CMTR |
| 9 |
Quantity |
Pieces, MT, or total area (m² / ft²) |
Download ASTM B575 Standard (PDF)
The official ASTM B575 PDF is available from our HT Pipe Download Center. The document covers Low-Carbon Nickel-Chromium-Molybdenum, Low-Carbon Nickel-Chromium-Molybdenum-Copper, Low-Carbon Nickel-Chromium-Molybdenum-Tantalum, Low-Carbon Nickel-Chromium-Molybdenum-Tungsten Alloy Plate, Sheet, and Strip, including full chemical composition tables, mechanical property requirements, dimensional tolerances, and testing provisions.
Go to Download Center | Request MTC / Quotation
12. Frequently Asked Questions
Q: What is the difference between C-276 and C-22?
Alloy C-276 (UNS N10276, Cr 14.5–16.5%, Mo 15.0–17.0%, W 3.0–4.5%) has higher Mo+W content for maximum resistance to reducing acids, pitting, and crevice corrosion. Alloy C-22 (UNS N06022, Cr 20.0–22.5%, Mo 12.5–14.5%, W 2.5–3.5%) has higher Cr content for superior oxidizing acid resistance while maintaining excellent reducing acid performance. Both have essentially identical PREN (~64). C-22 is generally preferred for mixed-acid environments with oxidizing species; C-276 is the benchmark for severe reducing acid and chloride environments. Price and availability are similar.
Q: What is the maximum service temperature for ASTM B575 alloys?
For sustained corrosion resistance, C-276 and C-22 are typically limited to approximately 425°C (800°F) in oxidizing environments. Above this temperature, chromium oxide volatilization can reduce corrosion resistance. For structural (non-corrosive) applications, these alloys maintain useful mechanical properties up to ~1000°C (1830°F) but are not typically selected for high-temperature structural service. For elevated-temperature applications where corrosion resistance is not critical, alloys like 625 (B443) or 800H/800HT (B409) are preferred.
Q: What makes ASTM B575 alloys resistant to pitting corrosion?
The exceptionally high molybdenum content (12.5–17.0% Mo) plus tungsten (up to 4.5% W) in C-type alloys produces PREN values of 60–72 — far exceeding 316L (~24–27), 904L (~34–39), and super-duplex stainless steels (~40–45). This high alloy content enables the formation of a highly stable passive chromium oxide film with enhanced Mo-rich sublayer, resisting chloride-induced breakdown even in concentrated brine at elevated temperatures. C-276 and C-22 remain pitting-resistant in seawater up to ~70°C (158°F) and in acidic chloride environments where stainless steels would fail rapidly.
Q: Can ASTM B575 plate be welded?
Yes, with careful procedure control. Ni-Cr-Mo alloys are welded using GTAW (TIG), GMAW (MIG), or SMAW with matching composition filler metals: ERNiCrMo-4 (C-276), ERNiCrMo-10 (C-22), ERNiCrMo-7 (C-4). Key requirements: low heat input (1.0–1.5 kJ/mm max), interpass temperature ≤ 93°C (200°F), and full inert gas shielding (argon with low O₂/ppm). Post-weld heat treatment is not required for solution-annealed base metal. The as-welded zone retains excellent corrosion resistance when proper procedures are followed. No preheat required.
Q: When should I specify Alloy 59 instead of C-276?
Alloy 59 (UNS N06059, Cr 22–24%, Mo 15–16.5%) offers the highest PREN (~72) and highest chromium content among B575 alloys, providing maximum pitting resistance and oxidizing acid resistance — surpassing C-276 in both metrics. Specify Alloy 59 when the environment contains the most aggressive mixed oxidizing-reducing acid combinations, very high chloride levels at elevated temperatures, or when C-276 has shown borderline performance. Alloy 59 is also preferred for wet phosphoric acid, oxidizing chloride solutions, and FGD scrubbers with high chloride concentration and acidity.
Request a Quote — ASTM B575 C-276 / C-22 Ni-Cr-Mo Alloy Plate, Sheet & Strip
Zhengzhou Huitong (HT Pipe) supplies ASTM B575 / SB575 Alloy C-276 (UNS N10276), C-22 (UNS N06022), C-4 (UNS N06455), and Alloy 59 (UNS N06059) plate, sheet, and strip in all standard dimensions. Full EN 10204 3.1 CMTRs, corrosion testing per ASTM G28 when specified. Competitive lead times from qualified Ni-Cr-Mo alloy mills.
