Bi-Metal Screws
Bi-Metal Solar Mounting Screw
SS304 + SS420 self-drilling screws for PV mounting rails and clamps, ceramic coated 1,000 h.
DINSS304
Rooftop solar on trapezoidal metal roofs
Fixing aluminium PV rails and clamps to steel roof sheet so the fixings outlast a 25-year panel warranty.
- Solar energysector
- Australia & Southeast Asiaregion
- 4screw types
- Samplesfor site tests
The challenge
PV systems mix aluminium rails, coated steel sheet and steel purlins under constant UV, thermal cycling and wind uplift. Carbon steel screws rust at the washer within a few years, and solid stainless screws cannot drill the purlin.
Our fastening solution
- Bi-metal SS304 + SS420 self-drilling screws with stainless-backed EPDM washers for rail feet into purlins up to 3 mm.
- Ceramic coating on the screw body as a barrier against galvanic contact with aluminium.
- Stainless hanger bolts for timber-framed roofs, supplied as kits with flange nuts and adapter plates.
- Lot-by-lot test reports for hardness, case depth and 1,000 h salt spray, filed with the installer.
Specification summary
| Main fixing | Bi-metal hex washer head, 5.5 × 32 mm, #3 point |
|---|---|
| Washer | SS304 + EPDM, 16 mm |
| Coating | Ceramic, 1,000 h |
| Packing | Kits per array, palletised by site |
Products used
Screws in this specification
Bi-Metal Screws
Bi-Metal Hex Washer Head Self-Drilling Screw
SS304 or SS316 body welded to an SS420 drill tip, indented hex washer head with SS + EPDM washer, M4.8–M7.
M4.8SS304 or SS316
Bi-Metal Screws
Bi-Metal Pan Head Star Drive Roofing Screw
SS304/316 + AISI 420 pan head Torx screw with EPDM washer, 16–400 mm, for standing seam and solar.
SS304 or SS316
Specialty Fasteners
Solar Hanger Bolt with EPDM Washer
A2 stainless double-thread hanger bolt, M8/M10/M12, with EPDM seal, nuts and adapter plate for PV roofs.
DINM8
More projects
Other applications
Steel warehouse with sandwich panel roof and walls
Long self-drilling screws for 100–150 mm insulated panels on hot-rolled purlins in a hot, dusty climate.
Commercial drywall fit-out on steel studs
Collated and loose screws for partitions and ceilings where speed and consistent countersinking drive the schedule.
Hardwood decking and timber structures
Corrosion-resistant timber screws that will not stain tannin-rich hardwood or split board ends.
Request for quotation
Get a fastening package quoted
Tell us the screw, size and quantity. A sales engineer replies within one business day with price, lead time and a sample offer.
- Emailinquiry@china-screw-factory.com
- WhatsApp+86 176 2154 1688
- Phone+86 176 2154 1688