ASTM A320 GRADE B8 & B8A BOLTS – MTC
ASTM A320 Grade B8 & B8A Sample MTC Certificate
Access a comprehensive, professionally formatted Material Test Certificate according to EN 10204-2004: 3.1 for ASTM A320 Grade B8 and B8A. Review the rigorous documentation verifying this Type 304 austenitic stainless steel's chemistry, carbide solution treatment, and mechanical strength intended for extreme low-temperature and cryogenic service.
What's Inside This A320 B8/B8A MTC Certificate
This sample mill test certificate highlights the essential testing parameters required for ASTM A320 Grade B8 and B8A—a premium Type 304 austenitic stainless steel engineered to retain extreme toughness and prevent brittle failure in cryogenic applications.
- Full Traceability: Certified with TC No.: S104/26-XX and fully mapped to ASTM A320 low-temperature bolting specifications.
- Type 304 Chemistry: Explicit verification of the 18.00-20.00% Chromium and 8.00-11.00% Nickel ranges, which provide the stable austenitic structure required for severe low-temperature environments.
- Carbide Solution Treatment: Verification of solution annealing processes. For Grade B8A, this MTC confirms the material was solution treated after all forming and threading operations to dissolve precipitated carbides and restore maximum corrosion resistance.
- Impact Test Exemption: Standard ASTM A320 verification that Charpy impact testing is not required, as austenitic stainless steels (like B8/B8A) are inherently immune to low-temperature embrittlement down to -425°F (-254°C).
- Mechanical Performance: Detailed logs of Tensile Strength (Min 515 MPa), Yield Strength (Min 205 MPa), high Elongation (Min 30%), and controlled Hardness (Max 192 HBW / 90 HRB for B8A compliance).
Live Preview: ASTM A320 Grade B8/B8A MTC Data
Review the standard parameters and layout before downloading the full document.
TC Number
S104/26-XX
TC Date
05.10.20XX
Material Spec
ASTM A320 GRADE B8A (Type 304)
Bar Shape / Size
Round Bar / 16 mm
Dimensions / Item
Hex Head Bolt M16-2P x 80 mm
Quantity
100.00 NOS
Chemical Composition %
| C | Mn | P | S | Si | Cr | Ni |
|---|---|---|---|---|---|---|
| 0.065 | 1.45 | 0.025 | 0.010 | 0.40 | 18.50 | 8.50 |
| 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 |
Mechanical Properties
| TENSILE STRENGTH (MPa) | YIELD STRENGTH 0.2% Offset (MPa) | % ELONGATION (GL-50mm) | HARDNESS (HBW) |
|---|---|---|---|
| 580.40 | 265.50 | 48.00 | 175, 178, 174 |
| Min: 515 (75 ksi) | Min: 205 (30 ksi) | Min: 30 | Max: 192 (For B8A) |
Standard References & Compliance
Our MTC certificates comprehensively align with the demanding specifications of the cryogenic and petrochemical processing sectors. The test reports confirm exact compliance with ASME/ASTM A320 / A320M with respect to the specific heat and lot tested.
| Standard / Requirement | Confirmation on Certificate |
|---|---|
| Visual Inspection | 100% visual inspection carried out & found free from defects. |
| Safety Requirements | Material is free from radioactive contamination and mercury. |
| Impact Testing | Exempt from impact testing per ASTM A320 (Austenitic Stainless Steel). |
| Dimensional Accuracy | All Dimensions are as per PO Specification / ASME B18.2.1. |
Certification Details
We confirm that the above mentioned items were Manufactured, Sampled, Tested, and Inspected in accordance with the subjected Customer's Purchase Order and applicable Drawings, Material Specifications, Codes & Standards.
Documentation Standard
- EN 10204-2004: 3.1 Standard
- Free from radioactive contamination
- Certified ISO 9001: 2015 Company
Heat Treatments
- Carbide Solution Treated
- Quenched: Water cooled
- Processed post-forming (B8A compliance)
Testing Conditions
- Mechanical tests carried out at room temperature
- 100% visual inspection carried out
Technical FAQs — ASTM A320 Grade B8 & B8A MTC
What is the difference between Grade B8 and Grade B8A?
Both are Type 304 stainless steel. The difference lies in the processing sequence and resulting hardness. Grade B8 (Class 1) is carbide solution treated, but can be machined/threaded after treatment, which can cause local work hardening. Grade B8A (Class 1A) guarantees that the fasteners are carbide solution treated after all forming, threading, and head-heading operations, ensuring a uniform, stress-free microstructure with a lower maximum hardness limit (192 HBW / 90 HRB).
Why are there no Charpy V-Notch impact test results on this MTC?
According to the ASTM A320 standard, austenitic stainless steels (such as Type 304 used in B8/B8A) are inherently ductile and do not exhibit a ductile-to-brittle transition temperature. Therefore, they are explicitly exempt from impact testing, even for cryogenic applications down to -425°F (-254°C).
Why use A320 B8/B8A instead of A193 B8?
While both specifications cover Type 304 stainless steel, ASTM A193 is designed for high-temperature service, whereas ASTM A320 is explicitly tailored and certified for low-temperature and cryogenic service. Using A320 documentation provides the necessary engineering assurance for systems operating well below freezing, such as LNG (Liquefied Natural Gas) facilities.