ASTM A320 — Low-temperature bolting
Bolts and studs in L7 and L7M, separate from A193 and linked to applicable nut and testing requirements.
- Reference
- ASTM A320/A320M — 26
- Configuration
- To specification and drawing
- Dimensions
- Specify units and tolerances
- Supply
- Confirm feasibility and documents
Technical drawing and dimensions to specify
Family selection guide. The drawing only identifies dimensions to specify; it does not identify a certified item, an available size range or a complete assembly. Final geometry and dimensions must match the approved drawing.
Dimensional data for the request
| Symbol | Required information | Units |
|---|---|---|
| d | Nominal thread and pitch | mm or inches, specify |
| L | Overall length; specify ends and measurement convention | mm or inches, specify |
Attach the dimensional standard or drawing, tolerances, quantity and configuration. Mechanical properties and grades appear below; they are not geometric dimensions.
Materials, grades and technical requirements
L7 and L7M: low-temperature bolting
Quenched and tempered alloy steels for bolts and studs. L7M has different hardness and strength requirements from L7: M does not mean “metric”. Specify minimum design temperature and required impact testing.
What to check for low-temperature service
| Field | Check |
|---|---|
| Temperature | Minimum design temperature, test temperature and applicable code criteria |
| Charpy impact | Required energy, specimen and lot results |
| Nuts | Compatible grade and testing; for L7M assess A194 7M with applicable requirements |
| Marking and documents | Grade, lot and test traceability |
Charpy test temperature is not automatically a universal minimum service temperature. Do not transfer A193 thermal values to A320.
L7 and L7M: separate enquiries
State the exact grade and project temperature conditions. The M suffix is not interpreted as a simple indication of metric thread.
Testing requirements
Include the tests and acceptance criteria required by the project. Documentation is reviewed against the configuration and supply lot.
Technical documentation
Dueemme technical sheet
Download technical PDF ↓Assembly and traceability
Lot, markings, component list and conformity documents relevant to the supply.
EN 10204 3.1 · DoP · CoC
State the required documents. Applicability and availability are confirmed during enquiry review.
Testing and coatings
Dimensional reports, mechanical tests, coating reports and ROCAP where applicable to the specification.
Application sectors
Industrial and EPC projects, according to the specified application.
Dueemme industries →Have a structural or ASTM specification?
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