Description
ISO 4762 Screw M6 x 40, Class 12.9, Steel — BOLTON SKU 57237.
About the ISO 4762 Screw M6 x 40
This is a hexagon socket head cap screw to ISO 4762 in M6 x 40 mm, made from alloy steel to property class 12.9, the highest of the commonly stocked metric strength grades. Class 12.9 denotes a nominal tensile strength of 1200 MPa with a yield stress ratio of 0.9, giving a nominal yield of approximately 1080 MPa, roughly half as much again as a class 8.8 screw of the same thread. ISO 4762 fixes the M6 head at a maximum diameter of 10.0 mm and a maximum height of 6.0 mm, driven by a 5 mm hexagon socket, on an ISO metric coarse thread of 1.0 mm pitch. The cylindrical head is designed to be counterbored below the surface. Because class 12.9 material is hardened, it is more notch-sensitive and less corrosion-tolerant than the lower classes, so a protective finish and controlled tightening both matter in service.
Key specifications
| Standard | ISO 4762 (equivalent to DIN 912) |
|---|---|
| Thread size | M6 × 1.0 (ISO metric coarse) |
| Nominal length | 40 mm |
| Property class | 12.9 (1200 MPa nominal tensile strength) |
| Head diameter (dk) | 10.0 mm max |
| Head height (k) | 6.0 mm max |
| Hexagon socket | 5 mm |
| Material | Alloy steel |
Typical applications
Class 12.9 M6 screws are specified where a small fastener has to carry a high preload: tooling and jig assembly, machine and gearbox covers, hydraulic manifold and valve-block fixing, die and fixture plates, and drive components that see reversing or vibratory loading. The 40 mm length gives usable grip through two moderately thick plates, or through a plate into a tapped boss. Because the joint depends on the preload the grade permits, screws of this class are normally torqued to a defined figure rather than tightened by feel.
Supplied by BOLTON Technical Equipment Supplies against request for quotation. Add this item to your RFQ basket to request pricing, lead time and documentation requirements (e.g. CoC, datasheets or test reports where applicable).
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