ISO 7090 Hardened Flat Washer for Structural Joints
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ISO 7090 Hardened Flat Washer for Structural Joints
ISO 7090 / ISO 7089 hardened flat washers distribute clamping load under high-strength structural bolts, preventing bearing-surface yield and preload loss. sinofastener supplies hardened flat washers for hull structure and deck steelwork in carbon steel 200HV / 300HV and A4 stainless, thread range M16–M64, with material certificates on request.
What Is an ISO 7090 Hardened Flat Washer?
AnISO 7090 hardened flat washer is a large-diameter plain washer with a chamfered outer edge, hardened to resist bearing deformation under high clamp loads. Under high-strength friction-grip and structural bolting, a hardened washer protects the bolt head and nut bearing faces, maintains uniform load distribution and preserves the required preload. It is the metric counterpart used with ISO 4014 structural bolts and hardened surface assemblies.
Marine Applications
Note: Application list based on typical industry practice for hardened flat washers; final requirement per structural design.
| Application | Serving |
|---|---|
| High-strength hull joints | Bearing-surface protection under clamp load |
| Structural steelwork | Load distribution & preload retention |
| Friction-grip connections | Matched with ISO 4014 structural bolts |
| Deck & superstructure | Fatigue-critical bolted joints |
Specifications & Materials
| Parameter | Range | Standard Reference |
|---|---|---|
| Thread size | M16–M64 | ISO 7090 / ISO 7089 |
| Hardness class | 200 HV / 300 HV | ISO 898-3 / ISO 7090 |
| Carbon steel | Hardened to 200HV/300HV | ISO 7090 |
| Stainless | A4 (316) | ISO 3506-1 |
| Certificate | EN 10204 3.1 / 3.2 on request | EN 10204 |
Why Choose sinofastener for Hardened Flat Washers?
1. Supplied to ISO 7090 / ISO 7089 with 200HV / 300HV hardness classes.
2. Hardened to resist bearing deformation under structural clamp load.
3. Carbon steel or A4 stainless matched to structural service.
4. EN 10204 3.1 / 3.2 documentation on request.
Standards Reference
- ISO 7090 — Plain washers, chamfered, product grade A (large-diameter series)
- ISO 7089 — Plain washers, product grade A (normal series)
- ISO 898-3 / hardness — Mechanical properties of fasteners and washers
- ISO 3506-1 — Mechanical properties of corrosion-resistant stainless steel fasteners
- EN 10204 — Metallic products, types of inspection documents
FAQ
Q1: What is the difference between ISO 7090 and ISO 7089?
ISO 7090 is the chamfered large-diameter series and ISO 7089 the normal series of plain washers; both are product grade A for hardened structural service.
Q2: What hardness is available?
Carbon steel hardness classes 200 HV and 300 HV, controlled for bearing resistance under high clamp load.
Q3: Why use a hardened washer in structural joints?
It prevents bearing-surface yield and preload loss under high-strength structural bolts, preserving joint integrity and fatigue life.
Q4: Can you provide material certificates?
Yes. EN 10204 3.1 as standard for qualified items; 3.2 subject to PO and class requirement.
Contact Us
Email: sales@sinofastener.com | bobo@sinofastener.com
Tel: 0574-86592068
Website: www.zlfastener.com | www.sinofastener.com (Main)
