ASTM A320 Grade L7 Sample MTC Certificate
Access a comprehensive, professionally formatted Material Test Certificate according to EN 10204-2004: 3.1 for ASTM A320 Grade L7. Review the rigorous documentation verifying this alloy steel's chemistry (AISI 4140), extreme low-temperature Charpy impact performance, and specialized heat treatments for safe service in sub-zero pressure environments.
What's Inside This A320 L7 MTC Certificate
This sample mill test certificate emphasizes the crucial testing parameters required for ASTM A320 Grade L7—a quenched and tempered Chromium-Molybdenum alloy steel (typically AISI 4140) engineered specifically for low-temperature fastening in pressure vessels, valves, and flanges.
- Full Traceability: Certified with TC No.: S121/26-XX and fully mapped to ASTM A320 low-temperature alloy steel bolting specifications.
- Charpy V-Notch Impact Testing: Explicitly logs passing impact test energy values at the mandated extremely low temperature of -150°F (-101°C), ensuring the material will not undergo brittle fracture in service.
- Alloy Verification (Cr-Mo): Detailed chemical breakdowns confirming the correct levels of Carbon, Chromium, and Molybdenum required to attain deep hardenability and low-temperature toughness.
- Controlled Tempering: Verification that the material was quenched and then tempered at a minimum of 1100°F (593°C) to relieve stress and lock in the necessary ductility.
- Mechanical Performance: Detailed logs of Tensile Strength (Min 860 MPa / 125 ksi), Yield Strength (Min 725 MPa / 105 ksi), Elongation (Min 16%), and Hardness (Max 321 HBW / 35 HRC).
Live Preview: ASTM A320 Grade L7 MTC Data
Review the standard parameters and layout before downloading the full document.
TC Number
S121/26-XX
TC Date
20.12.20XX
Material Spec
ASTM A320 GRADE L7 (Alloy Steel)
Bar Shape / Size
Round Bar / 24 mm
Dimensions / Item
Heavy Hex Bolt M24-3P x 150 mm
Quantity
200.00 NOS
Chemical Composition % (AISI 4140 Typical)
| C | Mn | P | S | Si | Cr | Mo |
|---|---|---|---|---|---|---|
| 0.42 | 0.85 | 0.015 | 0.012 | 0.25 | 0.95 | 0.20 |
| Min: 0.38 Max: 0.48 |
Min: 0.75 Max: 1.00 |
Max: 0.035 | Max: 0.040 | Min: 0.15 Max: 0.35 |
Min: 0.80 Max: 1.10 |
Min: 0.15 Max: 0.25 |
Mechanical & Impact Properties
| TENSILE STRENGTH (MPa) | YIELD STRENGTH 0.2% Offset (MPa) | % ELONGATION (GL-50mm) | HARDNESS (HBW) | IMPACT ENERGY @ -101°C (Joules) |
|---|---|---|---|---|
| 940.50 | 810.20 | 20.00 | 285, 288, 284 | 42, 45, 40 |
| Min: 860 (125 ksi) | Min: 725 (105 ksi) | Min: 16 | Max: 321 | Min: 27 (20 ft-lbf) @ -150°F |
Standard References & Compliance
Our MTC certificates comprehensively align with the demanding specifications of the low-temperature industrial sector. 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. |
| Charpy V-Notch Impact Test | Tested at -150°F (-101°C). Results meet minimum 20 ft-lbf requirement. |
| Safety Requirements | Material is free from radioactive contamination and mercury. |
| 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
- Quenched & Tempered
- Min Tempering Temp: 1100°F (593°C)
Testing Conditions
- Charpy Impact Test carried out at -150°F (-101°C)
- 100% visual inspection carried out
Technical FAQs — ASTM A320 Grade L7 MTC
What is the difference between A320 Grade L7 and A193 Grade B7?
Chemically and structurally, both are essentially identical, typically made from AISI 4140 chromium-molybdenum alloy steel. The critical difference is testing: A320 Grade L7 requires Charpy V-Notch impact testing at -150°F (-101°C) to guarantee low-temperature toughness, whereas A193 Grade B7 is intended for high-temperature service and does not mandate sub-zero impact testing.
Why is the 1100°F minimum tempering temperature critical?
Quenching alloy steel makes it very hard but also brittle. Tempering it at a minimum of 1100°F (593°C) trades away some of that excessive hardness in exchange for much-needed ductility and toughness. Without this proper tempering step, the fasteners could shatter under pressure in extreme cold environments.
What is Charpy V-Notch (CVN) testing?
CVN testing is a standardized high strain-rate test that determines the amount of energy absorbed by a material during fracture. For Grade L7, the metal is cooled to -150°F and struck by a pendulum. The MTC logs these values (in Joules or ft-lbf) to prove the steel absorbs at least 20 ft-lbf (27 J) of impact energy without shattering, confirming its safety for cryogenic piping and pressure vessels.