Fine-Thread All-Metal Hex Flange Lock Nuts manufactured in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) are dimensioned to ISO 12126. The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose A4 Stainless Steel for Fine-Thread All-Metal Hex Flange Lock Nuts
Specified for marine, coastal and chemical applications. For fine-thread all-metal hex flange lock nuts, this matters when superior, including marine and chloride environments is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80 |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C, subject to the property class and the joint |
| Corrosion characteristic | Superior, including marine and chloride environments |
Corrosion Behavior in Service
A4 (316) adds 2–3% molybdenum to the A2 (304) composition, which dramatically improves resistance to chloride-pitting corrosion. For Fine-Thread All-Metal Hex Flange Lock Nuts in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Fine-Thread All-Metal Hex Flange Lock Nuts, the alternative stainless grade is A2 (304). The practical dividing line is chlorides: A2 (304) is fine until salt is involved, and A4 (316) exists for the cases where it is — coastal, marine and road-salt service. Neither reaches the strength of a plated class 8.8 or 10.9 fastener.
Using Stainless Fasteners in Aluminum
Stainless steel is more noble than aluminum, so with an electrolyte present — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. Area ratio decides how bad it gets: a small stainless fastener in a large aluminum section is normally acceptable, a large stainless fastener in thin aluminum is not. Where the joint gets wet, isolate the metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.
Sizes of Fine-Thread All-Metal Hex Flange Lock Nuts Available in A4 Stainless Steel
| Size | Pitch P (mm) | c (mm) | d_a_max (mm) | d_a_min (mm) | d_c_max (mm) | d_w_min (mm) | Width across corners e (mm) | h_max (mm) | h_min (mm) | m_min (mm) | m_w_min (mm) | Width across flats s (mm) | s_min (mm) | r_max (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M8x1 | 1 | 1.2 | 8.75 | 8 | 17.9 | 15.8 | 14.38 | 9.4 | 8.74 | 7.64 | 4.6 | 13 | 12.73 | 0.5 | ISO 12126 |
| M10x1 | 1 | 1.5 | 10.8 | 10 | 21.8 | 19.6 | 16.64 | 11.4 | 10.34 | 9.64 | 5.6 | 15 | 14.73 | 0.6 | ISO 12126 |
| (M10x1.25) | 1.25 | 1.5 | 10.8 | 10 | 21.8 | 19.6 | 16.64 | 11.4 | 10.34 | 9.64 | 5.6 | 15 | 14.73 | 0.6 | ISO 12126 |
| M12x1.5 | 1.5 | 1.8 | 13 | 12 | 26 | 23.8 | 20.03 | 13.8 | 12.57 | 11.57 | 6.8 | 18 | 17.73 | 0.7 | ISO 12126 |
| (M12x1.25) | 1.25 | 1.8 | 13 | 12 | 26 | 23.8 | 20.03 | 13.8 | 12.57 | 11.57 | 6.8 | 18 | 17.73 | 0.7 | ISO 12126 |
| (M14x1.5) | 1.5 | 2.1 | 15.1 | 14 | 29.9 | 27.6 | 23.36 | 15.9 | 14.8 | 13.3 | 7.7 | 21 | 20.67 | 0.9 | ISO 12126 |
| M16x1.5 | 1.5 | 2.4 | 17.3 | 16 | 34.5 | 31.9 | 26 | 18.3 | 17.2 | 15.3 | 8.9 | 24 | 23.67 | 1 | ISO 12126 |
| M20x1.5 | 1.5 | 3 | 21.6 | 20 | 42.8 | 39.9 | 32.95 | 22.4 | 20.3 | 18.7 | 10.7 | 30 | 29.16 | 1.2 | ISO 12126 |
Dimensions are independent of the material: every size above is available in A4 Stainless Steel.
Custom manufacturing · Made to drawing
Need this nut in a grade that is not listed?
A4 Stainless Steel is one of the grades the catalog describes. Locking method is specifiable independently of the rest: nylon insert, all-metal deformed thread, serrated flange, or none. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
