ASTM A194 GRADE 8A (AISI 304)
ASTM A194 Grade 8A Nuts Sample MTC Certificate
Access a comprehensive, professionally formatted Material Test Certificate according to EN 10204-2004: 3.1 for Austenitic Stainless Steel Fasteners (ASTM A194 Grade 8A / AISI 304 Class 1A). Review verified chemistry arrays, strict mechanical proofs, and specialized post-machining solution annealing logs optimized for cryogenics and highly corrosive chemical infrastructure.
What's Inside This A194 Grade 8A MTC Certificate
This sample mill test certificate mirrors the strict QA documentation parameters mandatory for Class 1A solution-annealed AISI 304 austenitic stainless steel heavy hex nuts shipped for severe corrosion service configurations.
- Full Traceability: Certified under tracking index TC No.: S36/26-XX, fully correlated with verified mill heat identifiers to guarantee continuous tracking parameters.
- 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.
- Austenitic Chemistry Base: Comprehensive breakdown verifying precise Chromium (18.00-20.00%) and Nickel (8.00-11.00%) distributions, ensuring high environmental resistance against oxidation and general chemical attacks.
- 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 8A MTC Data
Review the standard parameters and layout before downloading the full document.
TC Number
S36/26-XX
TC Date
22.05.20XX
Material Spec
ASTM A194 Grade 8A (AISI 304 Class 1A)
Nut Profile / Size
Heavy Hex Nut / M16
Dimensions / Item
Heavy Hex Nut M16 x 2.0P
Quantity
900.00 NOS
Chemical Composition %
| C | Mn | P | S | Si | Cr | Ni | Fe |
|---|---|---|---|---|---|---|---|
| 0.052 | 1.74 | 0.034 | 0.012 | 0.51 | 18.35 | 8.25 | Rem |
| Max: 0.08 | Max: 2.00 | Max: 0.045 | Max: 0.030 | Max: 1.00 | Min: 18.00 Max: 20.00 |
Min: 8.00 Max: 11.00 |
Rem |
Mechanical & Hardness Properties
| BRINELL HARDNESS (HBW) | ROCKWELL HARDNESS (HRB) | PROOF LOAD STRESS (MPa) |
|---|---|---|
| 162 | 84 | 530 |
| Max: 233 | Max: 95 | Min: 515 (Heavy Hex Style) |
Standard References & Compliance
Our material quality records match structural limits required by maritime engineering, fluid transport networks, and low-temperature storage. 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)
- Liquid Quenched to achieve optimal carbide solution
Testing Conditions
- Hardness limits and proof load tracked at 25°C
- 100% thread clearance testing performed
Technical FAQs — ASTM A194 Grade 8A MTC Certificate
What is the exact technical significance of the "A" suffix in Grade 8A?
The "A" suffix stands for Class 1A processing. Standard Grade 8 nuts can be produced from stainless steel bars that were solution annealed prior to cold forming. In contrast, Grade 8A nuts must undergo a mandatory solution annealing heat treatment after they have been fully formed and machined. This step ensures all stress introduced during manufacturing is completely removed, providing optimal resistance to environmental stress corrosion cracking.
How does Grade 8A contrast with standard Grade 8 nuts in service applications?
Both grades use an AISI 304 chemical composition, but they differ in how cold-work stresses affect their properties. Standard Grade 8 nuts retain some hardness and strength from the cold-forming process, whereas Grade 8A nuts are fully softened by post-machining annealing. This makes Grade 8A the preferred choice for systems requiring maximum ductility and reliable corrosion resistance, particularly in cryogenic or highly sensitive chemical configurations.
Why does the specification cap the maximum hardness at 233 HBW?
Capping the hardness at 233 HBW (or 95 HRB) serves as quality confirmation that the post-machining solution annealing treatment was fully successful. Keeping the material below this threshold preserves its un-stressed austenitic state, which prevents localized corrosion and minimizes the risk of thread galling during high-torque assembly preloads.