Metric Hexagon Head Pipe Plugs — DIN 910 | Carbon Steel 35K | Grade 6.8 | Black Oxide / Zinc Cr3
FULLERKREG DIN 910 metric hexagon head screw plugs with collar in carbon steel 35K are the cost-effective, high-volume solution for sealing threaded ports in low-pressure piping systems, machine tools, hydraulic reservoirs, and general industrial equipment. Manufactured to full DIN 910 standard at Grade 6.8 strength, with a choice of black oxide or zinc plated Cr3 (trivalent chromium) surface finish, these plugs deliver reliable sealing performance where stainless steel is not required.
🔩 Product Overview
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Standard: DIN 910 (Hexagon Head Screw Plugs with Collar and Cylindrical Thread)
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Material: Carbon Steel 35K (medium carbon steel, equivalent to C35 / S35C)
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Strength Grade: 6.8 (per ISO 898-1)
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Surface Finish Options:
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Black Oxide — matte black finish, light corrosion protection, oil-retaining surface
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Zinc Plated Cr3 — trivalent chromium (RoHS-compliant), bright or clear zinc, enhanced corrosion resistance
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Thread Type: Metric cylindrical (parallel) thread
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Size Range: M10×1.5 to M48×1.5
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Drive: External hexagon head with integral collar
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Brand: FULLERKREG
📐 Dimensions & Size Chart (DIN 910)
All dimensions in mm. Weight in kg/1000 pcs.
| D (Nominal) |
D1 |
L |
C |
B |
M |
S |
Weight (kg/1000pcs) |
| M10×1.00 |
14 |
17 |
3 |
8 |
6 |
10 |
10.69 |
| M12×1.50 |
17 |
21 |
3 |
12 |
6 |
13 |
14.2 |
| M14×1.50 |
20 |
21 |
3 |
12 |
6 |
17 |
14.2 |
| M16×1.50 |
22 |
21 |
3 |
12 |
6 |
19 |
18.72 |
| M20×1.50 |
25 |
25 |
4 |
14 |
8 |
19 |
20.88 |
| M22×1.50 |
27 |
25 |
4 |
14 |
8 |
22 |
20.88 |
| M24×1.50 |
30 |
27 |
4 |
14 |
8 |
24 |
23.51 |
| M27×1.50 |
32 |
27 |
4 |
14 |
8 |
27 |
23.51 |
| M30×1.50 |
36 |
30 |
4 |
16 |
10 |
30 |
26.17 |
| M33×1.50 |
40 |
33 |
4 |
16 |
10 |
32 |
29.88 |
| M38×1.50 |
45 |
33 |
5 |
16 |
12 |
36 |
32.95 |
| M42×1.50 |
49 |
33 |
5 |
16 |
12 |
41 |
32.95 |
| M45×1.50 |
55 |
33 |
5 |
16 |
12 |
46 |
32.95 |
| M48×1.50 |
55 |
33 |
6 |
16 |
12 |
50 |
34.88 |
⚙️ Material & Mechanical Properties
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Material: Carbon Steel 35K (C35 / S35C — medium carbon steel, 0.32–0.39% C)
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Strength Grade: 6.8 per ISO 898-1
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Tensile Strength: ≥ 600 N/mm² (87,000 PSI)
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Proof Load Stress: ≥ 480 N/mm²
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Yield Strength (0.2%): ≥ 480 N/mm²
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Hardness: 190–250 HV
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Elongation: ≥ 8%
🎨 Surface Finish Options
Option 1: Black Oxide (Blackening)
- Matte black appearance — professional industrial look
- Formed by chemical conversion coating (magnetite Fe₃O₄)
- Light corrosion protection — suitable for indoor / dry environments
- Oil-retaining micro-porous surface reduces galling during installation
- No dimensional change — coating thickness <1 μm
- Typically used with supplemental oil or wax for enhanced protection
Option 2: Zinc Plated — Cr3 Trivalent Chromium (RoHS Compliant)
- Bright or clear zinc electroplating with trivalent chromium passivation
- RoHS compliant — no hexavalent chromium (Cr6+), meets EU environmental regulations
- Salt spray resistance: typically ≥ 72 hours (white rust) per ISO 9227
- Coating thickness: typically 5–12 μm
- Good corrosion protection for general indoor and light outdoor use
- Suitable for most general industrial and OEM applications
✅ Key Features & Benefits
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Cost-effective: Carbon steel construction offers significant cost savings over stainless steel for non-corrosive environments
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DIN 910 compliant: Full dimensional compliance ensures interchangeability with standard metric pipe fittings
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Collar design: Integral collar provides consistent seating depth and acts as a built-in stop to prevent over-insertion
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Pressure-tight sealing: Cylindrical parallel thread with collar delivers reliable metal-to-metal sealing for low-pressure systems
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Two finish options: Choose black oxide for a clean industrial aesthetic or zinc Cr3 for improved corrosion resistance
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Wide size range: M10 through M48 available from stock
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High-volume availability: Ideal for MRO, OEM, and production line procurement
🏭 Typical Applications
- Low-pressure hydraulic reservoir and manifold port closures
- Machine tool coolant and lubrication system plugging
- Gearbox and transmission housing drain/fill port sealing
- General industrial pipe and tube fitting closures
- Automotive and heavy equipment fluid system plugs
- Agricultural machinery and construction equipment
- MRO (Maintenance, Repair & Operations) stock items
- OEM production line fastener supply
📋 Standards & Compliance
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DIN 910 — Hexagon Head Screw Plugs with Collar and Cylindrical Thread
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ISO 898-1 — Mechanical properties of fasteners made of carbon steel and alloy steel
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ISO 9227 — Salt spray corrosion testing (for zinc plated finish)
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RoHS Directive 2011/65/EU — Zinc Cr3 finish is fully compliant (no Cr6+)
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REACH Regulation — Compliant
🔄 Surface Finish Comparison
| Property |
Black Oxide |
Zinc Cr3 (Trivalent) |
| Appearance |
Matte black |
Bright / clear silver |
| Coating Thickness |
<1 μm |
5–12 μm |
| Salt Spray (white rust) |
<24 hrs (without oil) |
≥72 hrs |
| RoHS Compliant |
Yes |
Yes (Cr3, no Cr6+) |
| Dimensional Impact |
Negligible |
Minimal (±5–12 μm) |
| Best For |
Indoor / dry, aesthetic preference |
General industrial / light outdoor |
| Lubricity |
Good (oil-retaining) |
Standard |
📦 Ordering & Packaging
- Available in standard bulk packaging (per 100 pcs or per 1000 pcs)
- Please specify surface finish when ordering: Black Oxide or Zinc Cr3
- Custom quantities available for OEM and production orders
- Clearly labelled with size, grade (6.8), finish type, and DIN 910 standard
- Fast dispatch — most sizes and finishes available from stock
❓ Frequently Asked Questions
Q: What is the maximum working pressure for DIN 910 Grade 6.8 carbon steel plugs?
A: DIN 910 plugs are designed for low-to-medium pressure sealing applications. The actual working pressure depends on thread size, material, and system design. For high-pressure hydraulic applications (≥20 MPa), we recommend consulting our technical team or considering higher-grade materials.
Q: What is the difference between black oxide and zinc Cr3 finish?
A: Black oxide provides a matte black aesthetic with minimal corrosion protection (best with supplemental oil), while zinc Cr3 offers a bright silver finish with significantly better corrosion resistance (≥72 hrs salt spray). Both are RoHS compliant.
Q: Is Cr3 zinc plating the same as Cr6 (hexavalent chromium)?
A: No. Cr3 (trivalent chromium) is the modern, RoHS-compliant replacement for the older Cr6 (hexavalent chromium) passivation. Cr3 contains no toxic hexavalent chromium and meets EU RoHS and REACH requirements.
Q: Can I use these plugs with a sealing washer or PTFE tape?
A: Yes. While the collar provides a metal-to-metal seal, PTFE tape or anaerobic thread sealant can be applied for additional leak-proofing, especially in systems with vibration or pressure fluctuations.
Q: Are these suitable for outdoor or wet environments?
A: Black oxide finish is recommended for dry indoor use only. Zinc Cr3 provides moderate outdoor protection for light exposure. For harsh outdoor, marine, or chemical environments, please consider our stainless steel DIN 910 range (A2 or A4).
Q: Can I get a material certificate for these plugs?
A: Yes. Material test reports and certificates of conformance are available upon request for FULLERKREG carbon steel fasteners.
All FULLERKREG DIN 910 carbon steel pipe plugs are manufactured and inspected to DIN standards. For bulk pricing, OEM supply, custom finishes, or technical support, please contact the FULLERKREG sales team.
