A4 Stainless Steel Foundation Bolts, L and J Form are supplied to our own published dimensions — this is a trade-series article rather than one covered by a dimensional standard, so confirm the figures against the part you are replacing. The grade provides superior, including marine and chloride environments and is largely non-magnetic; the practical service range is approx. -200 °C to +400 °C, subject to the property class and the joint.
Why Choose A4 Stainless Steel for Foundation Bolts, L and J Form
Specified for marine, coastal and chemical applications. For foundation bolts, l and j form, 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 |
Galvanic & Galling Considerations
Two important notes for stainless foundation bolts, l and j form: (1) stainless can gall on stainless threads under load — use a thread lubricant or anti-galling compound, especially for M6 and below; (2) when joined to aluminum or galvanized steel, stainless can drive galvanic corrosion of the less-noble metal in wet service — isolate with a coating or sleeve where appropriate.
Comparable Grades
For Foundation Bolts, L and J Form, 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
Expect the aluminum to corrode, not the fastener — stainless sits higher in the galvanic series, so the aluminum is the one that gives up material. A small fastener in a thick section spreads the loss over a large area and is usually fine; a large fastener in thin sheet concentrates it and is not. Keep water out of the joint, or isolate the two metals with a nylon or coated washer and a sealant.
Sizes of Foundation Bolts, L and J Form Available in A4 Stainless Steel
| Thread size | Form | Overall length L (mm) | Hook length (mm) | Thread length (mm) | Projection above concrete (mm) | Material | Finish |
|---|---|---|---|---|---|---|---|
| M12 | L | 300 | 50 | 60 | 60 | Class 4.6 / 8.8 steel | Hot-dip galvanised |
| M16 | L | 400 | 65 | 80 | 80 | Class 4.6 / 8.8 steel | Hot-dip galvanised |
| M16 | J | 400 | 80 | 80 | 80 | Class 4.6 / 8.8 steel | Hot-dip galvanised |
| M20 | L | 500 | 80 | 100 | 100 | Class 4.6 / 8.8 steel | Hot-dip galvanised |
| M20 | J | 500 | 100 | 100 | 100 | Class 4.6 / 8.8 steel | Hot-dip galvanised |
| M24 | L | 600 | 100 | 120 | 120 | Class 4.6 / 8.8 steel | Hot-dip galvanised |
| M30 | L | 750 | 120 | 150 | 150 | Class 4.6 steel | Hot-dip galvanised |
Dimensions are independent of the material: every size above is available in A4 Stainless Steel.
Custom manufacturing · Made to drawing
Need this bolt in a grade that is not listed?
A4 Stainless Steel is one of the grades the catalog describes. A non-standard bolt is quoted from the drawing; where one already exists in the catalog, the special is usually a variation on its tooling. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
