A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) is specified for marine, coastal and chemical applications. When wood construction screws (partially threaded) are specified in this grade, the dimensions remain per EN 14592; the material determines corrosion behavior (superior, including marine and chloride environments) and the service temperature range (approx. -200 °C to +400 °C, subject to the property class and the joint). Both are covered below with the size table.
Why Choose A4 Stainless Steel for Wood Construction Screws (Partially Threaded)
Specified for marine, coastal and chemical applications. For wood construction screws (partially threaded), 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 wood construction screws (partially threaded): (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 Wood Construction Screws (Partially Threaded), the alternative stainless grade is A2 (304). A2 (304) covers general indoor and outdoor service. A4 (316) adds molybdenum, which is what buys the chloride resistance for marine and de-icing-salt exposure. Where strength matters more than corrosion, plated alloy steel in class 8.8 or 10.9 is the swap to make.
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 Wood Construction Screws (Partially Threaded) Available in A4 Stainless Steel
| Nominal diameter (mm) | Head diameter dk (mm) | Drive | Thread length (mm) | Pilot hole in hardwood (mm) | Minimum edge distance (mm) | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| 4.0 | 8.0 | TX20 | 40 | 2.5 | 20 | 40~80 | EN 14592 |
| 5.0 | 10.0 | TX25 | 50 | 3.0 | 25 | 50~120 | EN 14592 |
| 6.0 | 12.0 | TX30 | 60 | 3.5 | 30 | 60~180 | EN 14592 |
| 8.0 | 16.0 | TX40 | 80 | 5.0 | 40 | 80~300 | EN 14592 |
| 10.0 | 20.0 | TX50 | 100 | 6.0 | 50 | 120~400 | EN 14592 |
