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.
- Body
- SS304 or SS316
- Tip
- AISI 420
- Head
- Pan, star drive
- Washer
- EPDM bonded
- Length
- 16–400 mm
- Thread
- BSD, CSD, Hi-Lo
- Free samplesUp to 20 pcs, ships in 7 days
- Lot test reportHardness, coating, drill time
- Made to orderCustom lengths, finishes, head marks
- Export readyFOB, CFR or CIF with full documents
Overview
Star (Torx) drive lets installers drive long bi-metal screws at high torque without cam-out. The large pan head and bonded washer seal well on profiled sheet.
Lengths from 16 mm up to 400 mm for insulated assemblies.
Applications
- Standing seam clips
- Solar roof hooks
- Insulated roofs
Used in these projects
Key features
- Star drive for high torque
- Sealed with bonded washer
- Lengths up to 400 mm
- Individual packaging available
Specifications
Typical values. Every dimension, hardness and coating is confirmed in writing with your quotation.
| Body | SS304 or SS316 |
|---|---|
| Tip | AISI 420 |
| Head | Pan, star drive |
| Washer | EPDM bonded |
| Length | 16–400 mm |
| Thread | BSD, CSD, Hi-Lo |
| Salt spray | 500–3,000 h |
| Sample | Free |
| HS code | 7318.14 / 7318.12 (by type) |
Buying guide
Applies to all bi-metal screws.
304 or 316 body
A2 (304) suits inland exterior use. A4 (316) contains 2–3 % molybdenum and resists chloride pitting, so specify it within about 5 km of the sea, near pools or in chemical plants.
Tip material
SS410/SS420 tips keep some corrosion resistance; SCM435 and C1022 tips drill faster in thick steel. The tip should break through before the stainless threads engage.
Isolate dissimilar metals
On aluminium solar rails and cladding use a stainless EPDM washer or a coated screw to reduce galvanic corrosion between the fastener and the profile.
Ordering
Packing and delivery
Standard terms for this product. Tell us if your market needs something different.
PackingSmall boxes, buckets or 20–25 kg cartons on fumigated pallets; private label available.
Lead timeSamples in 7 days; production 25–35 days after deposit.
PaymentT/T 30 % deposit, 70 % against B/L copy, or L/C at sight.
ShippingFOB Shanghai or Ningbo, CFR or CIF to your port.
Questions about this product
How thick a steel section can a bi-metal screw drill?
Depending on point size, from 0.75 mm sheet up to about 6 mm structural steel. For thicker purlins we recommend a #5 point carbon screw or pre-drilling.
Are bi-metal screws magnetic?
The 304/316 body is mostly non-magnetic, while the hardened tip is magnetic. That is a quick way to confirm a bi-metal screw on site.
Do you supply mill certificates?
Yes. Each lot ships with a material test certificate covering chemistry, hardness, case depth and salt spray results.
Bi-Metal Screws
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Request for quotation
Request a quotation for Bi-Metal Pan Head Star Drive Roofing Screw
Tell us the screw, size and quantity. A sales engineer replies within one business day with price, lead time and a sample offer.
- Email[email protected]
- WhatsApp+86 176 2154 1688
- Phone+86 176 2154 1688