ASTM A320 / A320M · LOW-TEMPERATURE BOLTING
ASTM A320 L7 Stud Bolts
Alloy-steel bolting for low-temperature service. A complete inquiry should state the applicable standard edition, impact-test basis, thread, length, end configuration, compatible nuts, finish and inspection documents.
PURCHASING BASIS
L7 is not complete without the temperature and test requirements.
ASTM A320/A320M covers alloy-steel and stainless-steel bolting for low-temperature service. The product should be evaluated against the purchase order, project specification and current applicable standard, rather than selected from the grade name alone.
- Standard
- ASTM A320/A320M; state the required edition and project specification.
- Grade
- L7 alloy-steel bolting. Do not substitute A193 B7 solely because the alloy family appears similar.
- Temperature basis
- State design/service temperature and the required impact-test temperature, acceptance criteria and evidence.
- Thread
- Metric, UNC, 8UN or drawing requirement; include pitch/TPI, class or tolerance and gauge requirement.
- Length and form
- State end-to-end length, effective thread lengths, chamfers and whether the part is continuous-thread, double-end or tap-end.
- Matched nuts
- ASTM A194 Grade 4 or Grade 7 may be compatible depending on the governing requirement; specify grade, dimensions, finish and low-temperature requirements.
- Finish
- Plain, black, galvanized or an approved coating system only as permitted by the project and assembly requirements.
- Documents
- MTC, heat-number traceability, mechanical and impact results, dimensions, coating records and third-party inspection when ordered.
RFQ CHECKLIST
Eight fields that prevent most quotation errors.
- 01ASTM designation and edition
- 02L7 grade and temperature basis
- 03Diameter and thread series
- 04Overall and effective thread lengths
- 05End configuration and chamfers
- 06Nut grade and quantity per stud
- 07Finish, lubrication and thread fit
- 08Quantity, packing, marks and documents
TECHNICAL CAUTION
Finish affects assembly, not only appearance.
Coating thickness can change thread fit, and lubrication can change the torque–tension relationship. Galvanized or coated assemblies may require matched nut processing. Final coating selection and tightening procedure should follow the project specification and engineering approval.
BUYER QUESTIONS
What should be confirmed before ordering?
Can A193 B7 be used instead of A320 L7?
Do not treat the two grades as automatically interchangeable. L7 is ordered for low-temperature service and its impact-test basis is part of the requirement. Any substitution requires review and approval against the governing specification.
Which nuts are paired with L7?
ASTM A194 Grade 4 or Grade 7 heavy hex nuts are commonly referenced as compatible. The order must still state the required nut grade, dimensions, finish and any low-temperature impact requirement.
What should appear on the quotation?
Include the standard and edition, grade, temperature/test basis, size, thread, length, end style, nuts, finish, quantity, marking, packing, destination and required inspection documents.
RELATED PROCUREMENT PAGES
REQUEST FOR QUOTATION
Send the grade, temperature basis, drawing, quantity and document requirements.
Handan Daiweike Metal Products Co., Ltd. · chuancy@daiweike.com · WhatsApp +63 918 642 3830
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