ASTM A320 GRADES L1 & L70 FASTENERS – MTC
ASTM A320 Grades L1 & L70 Sample MTC
Access a comprehensive, professionally formatted Material Test Certificate according to EN 10204-2004: 3.1 for ASTM A320 Grades L1 and L70 fasteners. Review the rigorous documentation verifying this unique low-carbon boron steel's chemistry, specialized quenching and tempering, and mandatory Charpy impact testing at -100°F (-73°C).
What's Inside This A320 L1/L70 MTC Certificate
This sample mill test certificate details the critical testing parameters required for ASTM A320 Grade L1 (and associated legacy or custom L70 designations). Grade L1 is a specialized Low-Carbon Boron Alloy Steel engineered to provide high strength and low-temperature toughness without relying on higher carbon or expensive heavy alloying elements.
- Full Traceability: Certified with TC No.: S162/26-XX and mapped to ASTM A320 low-temperature bolting specifications.
- Boron-Enhanced Chemistry: Explicitly logs the trace addition of Boron (0.0005 - 0.003%), which drastically improves the steel's hardenability despite its lower Carbon content (0.17 - 0.24%).
- Charpy V-Notch Impact Testing: Confirms passing impact test energy values at the specified low temperature of -100°F (-73°C), preventing brittle fracture in cold industrial applications.
- Controlled Heat Treatment: Verification that the material was fully quenched and tempered to lock in strength while relieving internal stresses.
- Mechanical Performance: Detailed logs conforming to high-strength requirements: Tensile Strength (Min 125 ksi / 860 MPa), Yield Strength (Min 105 ksi / 725 MPa), and Hardness mapping (Max 321 HBW).
Live Preview: ASTM A320 Grade L1 / L70 MTC Data
Review the standard parameters and layout before downloading the full document.
TC Number
S162/26-XX
TC Date
18.04.20XX
Material Spec
ASTM A320 GRADE L1 (Boron Steel)
Bar Shape / Size
Round Bar / 20 mm
Dimensions / Item
Hex Head Bolt M20-2.5P x 100 mm
Quantity
100.00 NOS
Chemical Composition % (Low-Carbon Boron)
| C | Mn | P | S | Si | B |
|---|---|---|---|---|---|
| 0.21 | 0.90 | 0.015 | 0.010 | 0.22 | 0.0015 |
| Min: 0.17 Max: 0.24 |
Min: 0.70 Max: 1.20 |
Max: 0.035 | Max: 0.040 | Min: 0.15 Max: 0.30 |
Min: 0.0005 Max: 0.003 |
Mechanical & Impact Properties
| TENSILE STRENGTH (MPa) | YIELD STRENGTH 0.2% Offset (MPa) | % ELONGATION (GL-50mm) | HARDNESS (HBW) | IMPACT ENERGY @ -73°C (Joules) |
|---|---|---|---|---|
| 920.50 | 795.20 | 19.50 | 280, 282, 278 | 40, 42, 38 |
| Min: 860 (125 ksi) | Min: 725 (105 ksi) | Min: 16 | Max: 321 | Min: 27 (20 ft-lbf) @ -100°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 -100°F (-73°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
- Processed for uniform hardenability
Testing Conditions
- Charpy Impact Test carried out at -100°F (-73°C)
- 100% visual inspection carried out
Technical FAQs — ASTM A320 Grade L1 & L70
What makes Grade L1 different from standard Grade L7?
Unlike Grade L7 which relies on Chromium and Molybdenum for hardenability (AISI 4140), Grade L1 is a low-carbon steel that utilizes a microscopic addition of Boron. Boron acts as an incredibly potent hardening agent, allowing this relatively simple, low-carbon steel to achieve the exact same high Tensile (125 ksi) and Yield (105 ksi) strengths as L7.
What is Grade L70 in relation to A320 specifications?
While Grade L1 is clearly defined in the ASTM A320 standard, "Grade L70" is often an industry colloquialism or legacy designation sometimes confused with L7, L7M (which has a 70 ksi yield option in some specs), or specific low-temperature boron variants. Fasteners requested as L70 are typically cross-referenced by engineers to meet the equivalent mechanical and impact parameters of A320 Grade L1 or L7 depending on the exact project requirements.
Why is Charpy impact testing done at -100°F instead of -150°F?
The ASTM A320 specification groups different alloys by their cryogenic capabilities. While highly alloyed steels like L7 (Cr-Mo) and L43 (Ni-Cr-Mo) are tested at -150°F (-101°C), the Boron-treated Grade L1 steel is certified for slightly less severe environments, with its mandatory Charpy V-Notch impact test threshold set at -100°F (-73°C).