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FULLERKREG Torx countersunk flat-head screws in alloy steel 10B21, Class 10.9 with Zinc Cr3 (trivalent chromium passivation) surface treatment are manufactured to GB/T 2673-2000 and ISO 14581 standards. Featuring a 90° countersunk head with an internal Torx (TX) drive, these high-strength screws deliver superior torque transmission, reduced cam-out risk, and a flush-mount finish. The Zinc Cr3 coating provides excellent corrosion resistance while remaining fully RoHS and ELV compliant — free of hexavalent chromium (Cr6+). Ideal for automotive, electronics, machinery, and precision assemblies requiring both high strength and environmental compliance.
| Attribute | Detail |
|---|---|
| Product Name | Torx Countersunk Flat Head Screws |
| Standard | GB/T 2673-2000 / ISO 14581 |
| Drive Type | Torx (TX) Internal Drive |
| Head Type | Countersunk (Flat Head), 90° included angle |
| Material | Alloy Steel 10B21 |
| Surface Treatment | Zinc Plated, Trivalent Chromium Passivation (Cr3 / Cr-III) |
| Coating Compliance | RoHS compliant, ELV compliant — Cr6+ free |
| Strength Grade | Class 10.9 |
| Size Range | M3 – M12 |
| Length Range | 6 mm – 100 mm |
| Brand | FULLERKREG |
| [ Photo 1 ] | [ Photo 2 ] | [ Photo 3 ] | [ Photo 4 ] |
Per GB/T 2673-2000 / ISO 14581 — Countersunk head with 90° included angle, Torx recess depth t, head diameter dk, head height k, thread pitch p.
| Thread d |
Pitch p (mm) |
TX Drive |
Head Dia. dk max (mm) |
Head Dia. dk min (mm) |
Head Height k max (mm) |
Head Height k min (mm) |
Recess Depth t min (mm) |
Recess Depth t max (mm) |
Min. Thread Length b (mm) |
Unit Weight (g / 100 pcs) |
|---|---|---|---|---|---|---|---|---|---|---|
| M3 | 0.50 | TX10 | 5.60 | 5.30 | 1.65 | 1.35 | 1.00 | 1.40 | 16 | — |
| M4 | 0.70 | TX20 | 7.50 | 7.14 | 2.20 | 1.86 | 1.30 | 1.80 | 20 | — |
| M5 | 0.80 | TX25 | 9.20 | 8.84 | 2.50 | 2.16 | 1.50 | 2.10 | 22 | — |
| M6 | 1.00 | TX30 | 11.00 | 10.57 | 3.00 | 2.61 | 1.80 | 2.50 | 24 | — |
| M8 | 1.25 | TX40 | 14.50 | 14.07 | 4.00 | 3.54 | 2.30 | 3.20 | 28 | — |
| M10 | 1.50 | TX50 | 18.00 | 17.57 | 5.00 | 4.54 | 2.80 | 3.80 | 32 | — |
| M12 | 1.75 | TX55 | 22.00 | 21.48 | 6.00 | 5.48 | 3.30 | 4.60 | 36 | — |
* All dimensions in mm. Tolerances per GB/T 2673-2000 / ISO 14581. Unit weight (g/100 pcs) to be updated upon batch confirmation.
| Thread | Available Lengths (mm) |
|---|---|
| M3 | 6, 8, 10, 12, 16, 20, 25, 30 |
| M4 | 6, 8, 10, 12, 16, 20, 25, 30, 35, 40 |
| M5 | 8, 10, 12, 16, 20, 25, 30, 35, 40, 45, 50 |
| M6 | 10, 12, 16, 20, 25, 30, 35, 40, 45, 50, 55, 60 |
| M8 | 12, 16, 20, 25, 30, 35, 40, 45, 50, 55, 60, 70, 80 |
| M10 | 20, 25, 30, 35, 40, 45, 50, 55, 60, 70, 80, 90, 100 |
| M12 | 25, 30, 35, 40, 45, 50, 55, 60, 70, 80, 90, 100 |
| Requirement | Recommendation |
|---|---|
| High strength + corrosion resistance | Class 10.9 Zinc Cr3 combines 1040 MPa tensile strength with enhanced zinc corrosion protection |
| RoHS / ELV compliance required | Zinc Cr3 (trivalent chromium) is fully Cr6+-free and compliant with EU RoHS & ELV directives |
| Flush surface finish required | Use countersunk head; ensure countersink angle matches 90° |
| Anti-cam-out / high torque drive | Torx (TX) drive preferred over Phillips or slotted for power tool use |
| Automotive / electronics assembly | Zinc Cr3 is the standard surface for automotive-grade fasteners requiring environmental compliance |
| Moderate outdoor / humid environment | Zinc Cr3 provides significantly better salt spray resistance than black oxide (typically 120–240 h NSS) |
| Severe corrosive / marine environment | Consider stainless steel A4 grade instead |
| Property | Black Oxide | Zinc Cr3 (Trivalent) | Zinc Cr6 (Hexavalent) | Hot-Dip Galvanized |
|---|---|---|---|---|
| Salt Spray Resistance | ~24–48 h | 120–240 h | 120–240 h | 500+ h |
| RoHS / ELV Compliant | Yes | Yes ✓ | No ✗ | Yes |
| Appearance | Matte black | Silver / clear / iridescent | Yellow iridescent | Dull grey |
| Coating Thickness | <1 μm | 5–12 μm | 5–12 μm | 45–85 μm |
| Thread Fit Impact | Negligible | Minor (within 6g tolerance) | Minor | Significant (re-tapping may be needed) |
| Typical Use | Indoor / dry | Automotive / general industrial | Legacy industrial | Heavy structural / outdoor |
GB/T 2673-2000 is the Chinese national standard for countersunk head screws with Torx recess, technically equivalent to ISO 14581:2011. Key parameters defined by the standard:
| Property | Class 10.9 Value |
|---|---|
| Material | Alloy Steel 10B21 (Boron-alloyed, Quenched & Tempered) |
| Min. Tensile Strength (Rm) | 1040 MPa |
| Min. Proof Load Stress (Sp) | 830 MPa |
| Min. Yield Strength (Rp0.2) | 940 MPa |
| Min. Elongation (A) | 9% |
| Hardness (Vickers) | 320–380 HV |
| Surface Treatment | Zinc Electroplating + Trivalent Chromium Passivation (Cr3) |
| Salt Spray Resistance | 120–240 h (neutral salt spray, per ISO 9227) |
| Coating Thickness | 5–12 μm (zinc layer) |
| Environmental Compliance | RoHS compliant, ELV compliant — Cr6+ free |
| Magnetic | Yes (ferromagnetic) |
| Heat Treatment | Quenched & Tempered (Q&T) |
| Item | Detail |
|---|---|
| Standard Pack | 100 pcs / bag, 1,000 pcs / box (varies by size) |
| MOQ | 100 pcs (standard sizes); custom quantities available |
| Labeling | Size, standard, material, grade, surface, quantity — FULLERKREG brand label |
| Custom Packaging | Available on request (OEM / private label) |
| Lead Time | In-stock items: 1–3 business days; custom orders: 7–15 business days |
🏭 Factory Direct — Manufactured in-house with full process control, no middlemen.
📐 Standard Compliant — Strictly per GB/T 2673-2000 / ISO 14581 and ISO 898-1; third-party inspection available.
🔬 Material Certified — Mill certificates (MTC) provided; 10B21 alloy composition and mechanical properties verified per batch.
✅ RoHS & ELV Compliant — Zinc Cr3 surface is fully Cr6+-free; compliance documentation available on request.
📦 Bulk Ready — Wholesale quantities from 100 pcs to millions; competitive tiered pricing.
🌍 Global Shipping — Export experience to 30+ countries; DDP / FOB / EXW terms available.
🔧 Technical Support — Engineering team available for selection guidance, drawings, and custom specs.
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