Property Class 12.9 Steel Closed-End Round-Body Blind Rivet Nuts are supplied to ISO 898-1 property class 12.9. Corrosion behaviour is requires plating or black-oxide protection, the material is magnetic, and the usable service range is commonly limited to approx. +300 °C; confirm against the coating and the load. In practice this grade is the highest common strength class, for high-load machine assembly.
- Grade
- ISO 898-1 property class 12.9
- Corrosion resistance
- Requires plating or black-oxide protection
- Magnetic response
- Magnetic
- Service temperature
- commonly limited to approx. +300 °C; confirm against the coating and the load
Property values are typical for the grade. Certified mechanical test data is available on request for production orders.
Closed-End Round-Body Blind Rivet Nuts manufactured in Property Class 12.9 Steel (ISO 898-1 property class 12.9) are dimensioned to Trade series (closed-end blind rivet nuts). The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose Property Class 12.9 Steel for Closed-End Round-Body Blind Rivet Nuts
The highest common strength class, for high-load machine assembly. For closed-end round-body blind rivet nuts, this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 12.9 |
|---|
| Magnetic response | Magnetic |
|---|
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
|---|
| Corrosion characteristic | Requires plating or black-oxide protection |
|---|
Corrosion Behavior in Service
Carbon and alloy steel closed-end round-body blind rivet nuts require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Comparable Grades
For Closed-End Round-Body Blind Rivet Nuts, class 8.8 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.
Sizes of Closed-End Round-Body Blind Rivet Nuts Available in Property Class 12.9 Steel
| Thread size | Pitch (mm) | Grip range (mm) | Installation hole (mm) | Head diameter (mm) | End | Material options |
|---|
| M4 | 0.7 | 0.5~2.5 | 6.1 | 9.0 | closed | zinc-plated steel / stainless steel / aluminum alloy |
| M5 | 0.8 | 0.5~3.0 | 7.1 | 10.0 | closed | zinc-plated steel / stainless steel / aluminum alloy |
| M6 | 1.0 | 0.5~3.0 / 3.0~5.0 | 9.1 | 12.0 | closed | zinc-plated steel / stainless steel / aluminum alloy |
| M8 | 1.25 | 0.5~3.0 / 3.0~5.5 | 11.1 | 15.0 | closed | zinc-plated steel / stainless steel / aluminum alloy |
| M10 | 1.5 | 1.0~3.5 | 13.1 | 17.0 | closed | zinc-plated steel / stainless steel / aluminum alloy |
Applications & Industries
What Closed-End Round-Body Blind Rivet Nuts are specified for, industry by industry. Stocked from M4 to M10.
Industries that specify Closed-End Round-Body Blind Rivet Nuts
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Outdoor enclosures
Cover and bracket attachment points exposed to water and dirt.
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HVAC fabrication
Panel hardware installed after the duct or enclosure has been formed.
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Refrigeration equipment
Sealed threaded mounting points in formed panels and closed housings.
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Vehicle bodywork
Blind threads in rails and box sections where the cavity must stay closed.
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Automotive & transport
Vibration-prone joints where the locking type is specified on the drawing.
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Maintenance & MRO
Replacements matched to the existing bolt class, thread and finish.
Typical applications
- forming the blind bulb within the specified grip range
- choosing steel, stainless steel or aluminum for the service environment
- adding a sealed internal thread from the front face of a panel
- keeping water and debris out of a closed section behind the insert
- joints re-torqued at a service interval
- completing a bolted joint on a stud, rod or bolt
Service conditions to specify against
- Marine and coastal
- Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
- High load
- Supplied in ISO 898-1 property classes, so the joint can be designed to a stated proof load and tightened to a calculated torque rather than by feel.
- Match the class
- A nut below the bolt property class strips before the bolt reaches its own limit — pair class 8 nuts with 8.8 bolts, class 10 with 10.9.
Where to use something else
- Do not drill to the thread minor diameter; the installation hole is set by the body and forming requirements.
Full application guide: where Closed-End Round-Body Blind Rivet Nuts are used, how to specify them, and the cases they are wrong for
