ASTM A320 GRADE B8M & B8MA BOLTS – MTC
ASTM A320 Grade B8M & B8MA Sample MTC Certificate
Access a comprehensive, professionally formatted Material Test Certificate according to EN 10204-2004: 3.1 for ASTM A320 Grade B8M and B8MA. Review the rigorous documentation verifying this Type 316 austenitic stainless steel's Molybdenum-enhanced chemistry, cryogenic toughness, and critical carbide solution treatments.
What's Inside This A320 B8M/B8MA MTC Certificate
This sample mill test certificate highlights the critical testing parameters required for ASTM A320 Grade B8M and B8MA—a premium Type 316 austenitic stainless steel designed to provide both extreme low-temperature toughness and superior resistance to chloride pitting and crevice corrosion.
- Full Traceability: Certified with TC No.: S112/26-XX and fully mapped to ASTM A320 low-temperature bolting specifications.
- Molybdenum Verification (Type 316): Explicit confirmation of the critical 2.00-3.00% Molybdenum addition, distinguishing it from B8/B8A and vastly improving resistance to marine and petrochemical chlorides.
- Class 1A Solution Treatment (B8MA): Verification that the material underwent carbide solution treatment after all forming and threading operations to dissolve precipitated carbides, ensuring a uniform microstructure with maximum corrosion resistance.
- Impact Test Exemption: Standard ASTM A320 verification that Charpy impact testing is not required, as Type 316 austenitic stainless steels retain excellent ductility and are 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 strict B8MA compliance).
Live Preview: ASTM A320 Grade B8M/B8MA MTC Data
Review the standard parameters and layout before downloading the full document.
TC Number
S112/26-XX
TC Date
12.11.20XX
Material Spec
ASTM A320 GRADE B8MA (Type 316)
Bar Shape / Size
Round Bar / 20 mm
Dimensions / Item
Heavy Hex Bolt M20-2.5P x 100 mm
Quantity
75.00 NOS
Chemical Composition %
| C | Mn | P | S | Si | Cr | Ni | Mo |
|---|---|---|---|---|---|---|---|
| 0.050 | 1.50 | 0.028 | 0.008 | 0.55 | 16.80 | 10.50 | 2.15 |
| Max: 0.08 | Max: 2.00 | Max: 0.045 | Max: 0.030 | Max: 1.00 | Min: 16.00 Max: 18.00 |
Min: 10.00 Max: 14.00 |
Min: 2.00 Max: 3.00 |
Mechanical Properties
| TENSILE STRENGTH (MPa) | YIELD STRENGTH 0.2% Offset (MPa) | % ELONGATION (GL-50mm) | HARDNESS (HBW) |
|---|---|---|---|
| 590.20 | 275.40 | 45.00 | 178, 180, 176 |
| Min: 515 (75 ksi) | Min: 205 (30 ksi) | Min: 30 | Max: 192 (For B8MA) |
Standard References & Compliance
Our MTC certificates comprehensively align with the demanding specifications of the cryogenic, marine, 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 (B8MA compliance)
Testing Conditions
- Mechanical tests carried out at room temperature
- 100% visual inspection carried out
Technical FAQs — ASTM A320 Grade B8M & B8MA MTC
Why choose B8M over B8 for low-temperature applications?
While both B8 (Type 304) and B8M (Type 316) offer excellent cryogenic toughness, the "M" in B8M denotes the addition of 2-3% Molybdenum. This specific alloy modification vastly improves the material's resistance to pitting and crevice corrosion, making B8M the required choice if the cryogenic environment is also exposed to harsh chlorides or marine atmospheres.
What is the difference between Grade B8M and Grade B8MA?
The difference is identical to B8 vs B8A, but applied to Type 316 steel. Grade B8M (Class 1) is carbide solution treated but may be machined afterward, leading to local work hardening. Grade B8MA (Class 1A) ensures the fasteners are solution treated after all forming and threading operations are complete. This results in a fully stress-relieved part with a lower maximum hardness limit (192 HBW) and restored optimal corrosion resistance.
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 316 used in B8M/B8MA) maintain a face-centered cubic (FCC) crystal structure that remains highly ductile even near absolute zero. Because they do not suffer from ductile-to-brittle transition, they are explicitly exempt from impact testing.