COMPREHENSIVE TECHNICAL ANALYSIS AND DATASHEET OF ASTM A194 GRADE 8NA NUTS
ASTM A194 Grade 8NA specifies premium austenitic stainless steel nuts manufactured from AISI Type 304N. This specialized grade takes the legendary 18/8 corrosion resistance of standard Grade 8 and boosts its mechanical capabilities through the precise metallurgical addition of Nitrogen (N).
What sets Grade 8NA apart is the crucial "A" designation, which mandates that the fasteners undergo a final Carbide Solution Treatment (full annealing) after all forging, machining, and threading operations are completed. This vital thermal process eliminates residual cold-work stresses, ensuring a fully softened, strictly non-magnetic state (Max 192 HBW).
■ Product Overview & Specifications
ASTM A194 Grade 8NA represents the industry benchmark for fully annealed, stress-free, nitrogen-alloyed austenitic pressure piping components.
| Material Classification | Nitrogen-Strengthened Austenitic Stainless Steel (Type 304N - Annealed) |
|---|---|
| UNS Designation | S30451 |
| Magnetic State | Strictly Non-Magnetic (Annealed post-machining) |
| Size Range | Metric: M6 to M100 | Imperial: 1/4" to 4" |
| Strengthening Method | Nitrogen Solid-Solution Strengthening & Full Solution Annealing |
■ Proprietary Datasheet Download (GATED)
ASTM A194 Grade 8NA — Complete Technical Datasheet
Contains detailed proof load thresholds, dimensional tolerances for ASME B18.2.2 standard and heavy hex profiles, and precise galling-prevention torque values for A193 B8NA assemblies.
⬇ DOWNLOAD DATASHEET■ MTC Integration Section
Material traceability is the backbone of safety in high-pressure environments. Every lot shipped by Ananka is accompanied by fully authenticated documentation mapping back to raw steel mill certificates.
- EN 10204 Type 3.1: Issued by our independent quality department, providing specific heat-traceable test results (actual chemical analysis, mechanical test results, hardness, and proof load tests).
- EN 10204 Type 3.2: For critical commercial, offshore, or chemical applications, we facilitate third-party witness testing.
■ Chemical Composition
| Carbon (C) | Manganese (Mn) | Chromium (Cr) | Nickel (Ni) | Nitrogen (N) | Phosphorus (P) | Sulfur (S) | Silicon (Si) |
|---|---|---|---|---|---|---|---|
| 0.08 Max | 2.00 Max | 18.00 – 20.00 | 8.00 – 11.00 | 0.10 – 0.16 | 0.045 Max | 0.030 Max | 1.00 Max |
■ Mechanical Properties
Grade 8NA is explicitly annealed after all machining, removing any localized cold-work hardening. Therefore, ASTM caps its maximum hardness.
| Mechanical Property | Grade 8NA (Annealed) Limits |
|---|---|
| Proof Load Stress (Heavy Hex) | 80 ksi (550 MPa) |
| Hardness Limit (Rockwell) | 90 HRB Maximum |
| Hardness Limit (Brinell) | 192 HBW Maximum |
■ Compatible Fastener Assemblies
| Internal Threads (A194 Gr 8NA) | Mating Bolts (A193 Gr B8NA) | Mating Studs (A193 Gr B8NA) |
|---|---|---|
| Grade 8NA Heavy Hex Nuts (Annealed) | ASTM A193 Grade B8NA Bolts | A193 Grade B8NA Double End Studs |
