ASTM A194 GRADE 8MLCuN NUTS
ASTM A194 Grade 8MLCuN Nuts Sample MTC Certificate
Access a comprehensive, professionally formatted Material Test Certificate according to EN 10204-2004: 3.1 for 6% Moly Super Austenitic Stainless Steel Fasteners (ASTM A194 Grade 8MLCuN / UNS S31254). Verify verified chemistry arrays, high pitting resistance equivalents (PREn), and specialized post-machining solution annealing logs optimized for aggressive chloride environments and offshore infrastructure.
What's Inside This A194 Grade 8MLCuN MTC Certificate
This sample mill test certificate mirrors the strict QA documentation parameters mandatory for Class 1A solution-annealed premium super austenitic stainless steel heavy hex nuts shipped for severe corrosion service configurations.
- Full Traceability: Certified under tracking index TC No.: S79/26-XX, fully correlated with verified mill heat identifiers to guarantee continuous product verification.
- Class 1A Solution Annealing: Explicit confirmation that the nuts have been solution annealed as a final step after machining or cold forming, ensuring all residual stresses are fully eliminated.
- 6% Moly Premium Chemistry: Comprehensive breakdown verifying precise Molybdenum (6.00-6.50%), Chromium (19.50-20.50%), Nickel (17.50-18.50%), Copper (0.50-1.00%), and Nitrogen (0.18-0.22%) distributions to secure an ultra-high PREn value (≥ 42).
- Galling & Hardness Control: Hardness values tracked closely below the standard limit of 233 HBW (95 HRB maximum) to preserve structural ductility and prevent thread galling under high torque preloads.
- Quality Compliance: 100% visual inspection carried out and verified free from defects and radioactive contamination.
Live Preview: ASTM A194 Grade 8MLCuN MTC Data
Review the standard parameters and layout before downloading the full document.
TC Number
S79/26-XX
TC Date
12.08.20XX
Material Spec
ASTM A194 Grade 8MLCuN (UNS S31254 Class 1A)
Nut Profile / Size
Heavy Hex Nut / M24
Dimensions / Item
Heavy Hex Nut M24 x 3.0P
Quantity
350.00 NOS
Chemical Composition %
| C | Mn | P | S | Si | Cr | Ni | Mo | Cu | N | Fe |
|---|---|---|---|---|---|---|---|---|---|---|
| 0.015 | 0.65 | 0.024 | 0.005 | 0.42 | 20.10 | 18.15 | 6.22 | 0.78 | 0.202 | Rem |
| Max: 0.020 | Max: 1.00 | Max: 0.030 | Max: 0.010 | Max: 0.80 | Min: 19.50 Max: 20.50 |
Min: 17.50 Max: 18.50 |
Min: 6.00 Max: 6.50 |
Min: 0.50 Max: 1.00 |
Min: 0.18 Max: 0.22 |
Rem |
Mechanical & Hardness Properties
| BRINELL HARDNESS (HBW) | ROCKWELL HARDNESS (HRB) | PROOF LOAD STRESS (MPa) |
|---|---|---|
| 182 | 89 | 540 |
| Max: 233 | Max: 95 | Min: 515 (Heavy Hex Structural Standard) |
Standard References & Compliance
Our material quality records match structural limits required by maritime engineering, saltwater desalination networks, and oil/gas extraction facilities. The surfaces pass visual checks with no anomalies found.
| Standard / Requirement | Confirmation on Certificate |
|---|---|
| Visual Inspection | 100% visual inspection carried out & found free from defects. |
| Safety Requirements | Material is certified free from radioactive contamination. |
| Weld Repairs | No weld repairs performed on finished stainless elements. |
| Dimensional Accuracy | All heavy hex sizing verified against ASME B18.2.2 requirements. |
Certification Details
We confirm that above mentioned Items was Manufactured, Sampled, Tested and Inspected in accordance with the subjected Customer's Purchase Order and as applicable Drawings, Material Specifications, Codes & Standards and the results of the items have been determined to meet the users' requirements.
Documentation Standard
- EN 10204-2004: 3.1 Compliance
- Free from radioactive contamination
- Certified ISO 9001: 2015 Operation
Heat Treatments
- Class 1A Solution Annealed (Post-Machining)
- Rapidly Quenched to secure uniform alloy retention
Testing Conditions
- Hardness limits and proof load tracked at 25°C
- 100% thread clearance testing performed
Technical FAQs — ASTM A194 Grade 8MLCuN MTC Certificate
What metallurgical benefit does the 6% Molybdenum addition provide to Grade 8MLCuN nuts?
ASTM A194 Grade 8MLCuN nuts are derived from a 6% Moly super austenitic stainless steel base (UNS S31254). The exceptionally high level of Molybdenum (6.00-6.50%), augmented by Nitrogen and Chromium, yields a Pitting Resistance Equivalent Number (PREn) greater than 42. This structural composition provides supreme resistance against localized pitting and crevice corrosion in hot chlorinated media, sour gases, and brackish seawater layouts where traditional grades fail.
Why is a post-machining Class 1A solution annealing process mandatory for this grade?
Due to the massive alloy content of 6% Moly stainless steel, cold forming or tapping operations introduce significant severe internal strain that can precipitate brittle intermetallic phases like sigma. Executing a mandatory solution heat treatment followed by rapid liquid quenching after all machining operations eliminates this residual stress and fully re-dissolves any precipitates back into a homogeneous austenitic structure, maximizing corrosion thresholds.
What absolute maximum hardness limits are enforced for certified Grade 8MLCuN elements?
Per ASTM A194 specifications, Grade 8MLCuN heavy hex nuts must strictly show a maximum hardness threshold of 233 HBW (Brinell scale) or 95 HRB (Rockwell B scale). Keeping the material under this boundary serves as standard verification of a successful annealing profile, protecting threads from galling and maintaining supreme structural elongation parameters.