As global construction projects increasingly adopt international design codes, metric DTI washers have become essential components for European-designed structural steel connections. Navigating the specifications between North American and European standards requires precision and a trusted manufacturing partner. FULLERKREG engineers dual-compliant load-indicating washers that bridge the gap between global requirements. Whether you are an export fabricator or an engineer working on international infrastructure, understanding the nuances of M12 to M36 DTI washers ensures your connections meet the required minimum pretension safely and reliably. Explore our complete DTI washer collection for high-performance fastening solutions. For custom metric requirements, contact our technical team at sales@fullerkr.com.
Metric DTI Washer Size Range M12 to M36
| Metric Size | Approx. Inch Equivalent | Typical Washer OD (mm) | Typical Washer ID (mm) | Common Applications |
|---|---|---|---|---|
| M12 | 1/2" | 32.0 | 13.0 | Light structural framing |
| M16 | 5/8" | 37.0 | 17.0 | Standard building structures |
| M20 | 3/4" | 44.0 | 21.0 | Heavy structural columns/beams |
| M22 | 7/8" | 50.0 | 23.0 | Bridges and infrastructure |
| M24 | 1" | 56.0 | 25.0 | Heavy-duty civil engineering |
| M27 | 1-1/8" | 62.0 | 28.0 | Industrial equipment foundations |
| M30 | 1-1/4" | 68.0 | 31.0 | Power plants and high-rises |
| M36 | 1-1/2" | 78.0 | 37.0 | Massive structural base plates |
Note: The dimensions provided above are typical values. Exact specifications should always be verified against specific EN 14399-9 or ASTM F959M data sheets prior to procurement.
Metric DTI Washer Material Grades
C-45 (Carbon Steel)
A medium carbon steel widely utilized for washer bodies due to its excellent formability and predictable response to heat treatment, ensuring the DTI protrusions compress accurately under structural loads.
Grade 8.8
Featuring a nominal tensile strength of 800 MPa and a yield ratio of 0.8, Grade 8.8 bolts are the metric equivalent to ASTM A325, suitable for standard commercial and industrial structural joints.
Grade 10.9
With a high nominal tensile strength of 1,000 MPa and a 0.9 yield ratio, Grade 10.9 bolts align with ASTM A490 requirements, designed for heavy-duty connections in bridges and highly stressed infrastructure.
| Metric Grade | Min. Tensile Strength | Yield Ratio | Approx. ASTM Equivalent | Typical Use Case |
|---|---|---|---|---|
| C-45 | N/A (Washer Body) | N/A | Medium Carbon Steel | General DTI manufacturing |
| 8.8 | 800 MPa | 0.8 | ASTM A325 / F1852 | Standard structural bolting |
| 10.9 | 1000 MPa | 0.9 | ASTM A490 / F2280 | Heavy structural bolting |
Dual Standard Compliance ASTM F-959 and EN 14399-9
ASTM F-959
The primary American standard, perfectly aligned with RCSC/AISC specifications. It outlines the requirements for compressible-washer-type direct tension indicators, mandating a maximum hardness of 37 HRC to prevent hydrogen embrittlement in structural applications.
EN 14399-9
The European standard specifically developed for high-strength (HV) structural bolting assemblies for preloading. It aligns with EN 1090 execution classes and is essential for obtaining CE marking or Declarations of Performance (DoP) in the European market.
FULLERKREG's dual certification ensures that our metric DTI washers can be seamlessly utilized on international projects spanning multiple regulatory jurisdictions.
ASTM F-959 vs EN 14399-9 Comparison
| Parameter | ASTM F-959 (Metric) | EN 14399-9 |
|---|---|---|
| Size Range | M16 to M36 | M12 to M36 |
| Material Hardness | Max 37 HRC | 300 - 370 HV |
| Bolt Grade Pairing | Class 8.8 / 10.9 (Equivalent) | System HR / HV Assemblies |
| Installation Methods | DTI under head or nut | Specific to EN 14399 system requirements |
| Inspection | Feeler gauge refusal count | Feeler gauge according to EN 1090-2 |
| Documentation | MTRs and Certificates of Conformance | CE Marking and DoP |
Metric DTI Washer Finish Options
- Plain: Ideal for indoor, climate-controlled environments and enclosed structural frames.
- Mechanically Galvanized: Compliant with ASTM B695/EN ISO 10684, providing excellent protection in moderately corrosive environments.
- Hot-Dip Galvanized: Meets ASTM A153/EN ISO 1461, offering the ultimate long-term protection for outdoor and heavy marine applications.
- Geomet/Dacromet: High-performance zinc-flake coatings offering exceptional corrosion resistance with minimal coating thickness.
When to Specify Metric DTI Washers
- International projects: Any structure being built outside of North America typically demands metric fastening specifications.
- European equipment integration: Essential when anchoring imported heavy machinery that utilizes metric bolts.
- Dual-code buildings: Projects designed in the US but built overseas requiring compliance with both AISC and Eurocodes.
- Metric substitution: When local supply chains necessitate replacing imperial bolts with their exact metric equivalents.
- Export fabrication: Steel fabricators building structural modules domestically for final assembly in metric-standard regions.
Squirtern DTI Washers in Metric Sizes
Upgrade your installation speed and inspection accuracy globally with our proprietary visual indication technology.
- Provides immediate visual confirmation of required tension without the need for manual feeler gauges on every bolt.
- Drastically reduces QA/QC labor time and costs, keeping large structural projects on schedule.
- Improves job site safety by allowing inspectors to verify joint tension from a safe distance.
- Maintains full compliance with standard mechanical compression requirements and material standards.
Explore our metric Squirtern DTI washers or contact sales@fullerkr.com for full technical specifications.
Frequently Asked Questions
What metric sizes do DTI washers come in?
FULLERKREG metric DTI washers are available in standard structural sizes ranging from M12 up to M36, covering the vast majority of heavy bolting applications.
What is EN 14399-9?
EN 14399-9 is the European standard specifying the precise requirements for direct tension indicators used in high-strength structural bolting assemblies for preloading.
What grades are available for metric DTI washers?
Metric DTI washers are commonly manufactured from C-45 carbon steel and are calibrated to be used alongside high-strength structural bolts in Grade 8.8 and Grade 10.9.
How do metric grades 8.8 and 10.9 compare to ASTM A325 and A490?
Grade 8.8 is the metric equivalent to ASTM A325, with similar tensile strength requirements. Grade 10.9 is the metric equivalent to the higher-strength ASTM A490 bolts.
Can metric DTI washers be used on US projects?
Yes, provided the project's engineering design specifically calls for metric fasteners and the DTI washers meet the ASTM F959M (metric) specification.
Where can I buy metric M12 to M36 DTI washers?
You can purchase them directly from FULLERKREG. Visit our Squirtern DTI washers collection or email sales@fullerkr.com for bulk orders and technical support.
Secure Your International Projects with FULLERKREG
Ensure total compliance and unmatched structural integrity with our dual-certified metric DTI washers.
For custom engineering inquiries or global logistics, email sales@fullerkr.com.