ASTM A320 Gr. L7M STUD BOLT C/W 2 HEAVY HEX NUTS A194 Gr 7M
We are a professional manufacturer and exporter of ASTM A320 L7M stud bolt A194 7M Heavy Hex nuts in China
ASTM A320 L7M Stud Bolts are used for LOW temperature performance. These fasteners are commonly used for valves, flanges, fittings, and pressure vessels . ASTM specifications recommend a minimum Charpy impact value for ASTM A320 L7M Stud Bolts to be 20-ft-lbf @ -100F.
ASTM A320 L7M is manufactured from AISI 4140 round bar and supplied in a quenched and tempered condition.it can be provided with supplementary testing as defined in ASTM A320. This material can also be offered fully in compliance with the additional requirements of API 20E BSL 1, 2 and 3.
ASTM A320 L7M Chemical composition
| Element | Composition, % A |
|---|---|
| Chromium Molybdenum B | |
| Carbon, max | 0.38 – 0.48 |
| Manganese | 0.75 – 1.00 |
| Phosphorus, max | 0.035 |
| Sulfur, max | 0.040 |
| Silicon | 0.15 – 0.35 |
| Chromium | 0.80 – 1.10 |
| Molybdenum | 0.15 – 0.25 |
ASTM A320 Impact Test Requirements (Notch Toughness)
| Size of Specimen, mm | Test Temperature | Minimum impact value required for average of each set of three specimens, ft-lbf [J] | Minimum impact value permitted for one specimen only of a set, ft-lbf [J] | |
|---|---|---|---|---|
| °F | °C | |||
| 10 X 10 | -100 | -73 | 20 [27] | 15 [20] |
| 10 X 7.5 | 16 [22] | 12 [16] | ||
A194 7M Nuts and Washers
A194 Grade 7M nuts at a hardness not exceeding 235 HBW (or equivalent) shall be used with Grade L7M bolts, studs, and stud bolts. All nut impact tests shall be made on test specimens taken from the bar or plate from the heat of steel used for manufacturing the nuts, and heat treated with the nut blanks.
A320 L7M Stud bolt heat Treatment
For L7M bolting, the final heat treatment, which may be the tempering or stress-relieving operation conducted at 1150 °F [620 °C] minimum, shall be done after machining or rolling of the threads and any type of cutting
A320 L7M Stud bolt Hardness requirement
The maximum hardness of Grade L7M shall be 235 HBW or 99 HRB (conversion in accordance with Table Number 2B of Test Methods and Definitions A370). Minimum hardness shall not be less than 200 HBW or 93 HRB. Conformance to this hardness shall be ensured by testing each bolt or stud by Brinell or Rockwell B methods in accordance with 6.3.1
A320 L7M Product Marking
In addition to the requirements of Specification A962/ A962M,
Grade L7M shall be 100 % evaluated in conformance with this specification and shall have a line under the grade symbol.
Nuts from materials that have been impact tested shall be marked with the letter “L.”
Surface Treatments
-
- Plating
- Zinc (White / Yellow / Black)
- Cadmium (White / Yellow / Black)
- Zinc Nickel
- Plating
-
- Galvanising
- Hot-Dipped Galvanise
- Mechanical Galvanise
- Galvanising
-
- Fluorocarbon Coating
Xylan® / Dupont Coating Systems:- Xylar 2
- Xylan 1070
- Xylan 1424
- Fluorocarbon Coating
- Customised Coating Systems
- Zinc + Fluorocarbon / PTFE coated stud bolt
- Cadmium + Fluorocarbon /PTFE coated stud bolt
- Zinc Nickel + Fluorocarbon /PTFE coated stud bolt
- Zinc Plating + Xylan 1424 Blue PTFE coated stud bolt
- Xylar 2 + Xylan 1070 coated stud bolt
ASTM A320 L7M stud bolt A194 7M Heavy Hex nuts Supply Scope:
FULL-THREAD, 8-UN, ASME B18.2.1/B1.1 CL.2A/ A194/A194M-7M, WITH TWO HEAVY HEX. NUTS, ASME B18.2.2/B1.1 CL.2B,
BOLT, StdBlt, A320L7M/7M, Stud Bolt – Threaded Full Length Alloy Steel Per ASTM A320-L7M with Three Carbon Steel Nuts Per A194-7M Threads to ISO Metric DIN 13 with Nuts to DIN 934
This thread is a globally standardized thread, it replaces older metric thread and most threads with inch dimensions. The label consists of the letter M followed by a number indicating the nominal diameter, the flank angle is 60 °.
