DIN 7991 Countersunk Socket Head Screws
DIN 7991 Countersunk Socket Head Screws feature a 90° countersunk head that sits flush with the surrounding surface when properly installed. This head design keeps the fastening point smooth and unobtrusive, while the internal hex drive provides direct tool engagement without requiring additional space around the screw head.
The flush-fitting design is particularly useful for components where a protruding fastener could interfere with movement, assembly, or the finished surface. DIN 7991 screws are available in a range of metric sizes, including M3 to M24, with carbon and alloy steel as well as stainless steel options for different mechanical and environmental requirements. They are commonly used in machinery, equipment, metal components, brackets, fixtures, and precision mechanical assemblies where a clean surface finish and compact fastening arrangement are important.
Specification:
| Item | Specificaiton |
|---|---|
| Standard | DIN7991 |
| Product Type | Countersunk Socket Head Screw |
| Head Angle | 90° |
| Drive | Internal Hexagon |
| Thread Standard | ISO 68-1,ISO 965 |
| Thread Tolerance | 6g |
| Material | Carbon Steel,Alloy Steel,Stainless Steel |
| Steel Property | ISO 898-1 |
| Stainless Steel Property | ISO 3506-1 |
| Size Range | M3-M24 |
| Surface Treatment | Black Oxidation,Zinc Plated, Dacromet,Bright Finish, Passivation |
Dimension Chart of DIN7991 Countersunk Socket Head Screws:
| Thread Diameter | M3 | M4 | M5 | M6 | M8 | M10 | M12 |
| P | 0.5 | 0.7 | 0.8 | 1 | 1.25 | 1.5 | 1.75 |
| dk max | 6 | 8 | 10 | 12 | 16 | 20 | 24 |
| dk min | 5.7 | 7.64 | 9.64 | 11.57 | 15.57 | 19.48 | 23.48 |
| e min | 2.3 | 2.87 | 3.44 | 4.58 | 5.72 | 6.86 | 9.15 |
| k max | 1.7 | 2.3 | 2.8 | 3.3 | 4.4 | 5.5 | 6.5 |
| s min | 2.02 | 2.52 | 3.02 | 4.02 | 5.02 | 6.02 | 8.025 |
| s max | 2.1 | 2.6 | 3.1 | 4.12 | 5.14 | 6.14 | 8.175 |
| t max | 1.2 | 1.8 | 2.3 | 2.5 | 3.5 | 4.4 | 4.6 |
| t min | 0.95 | 1.55 | 2.05 | 2.25 | 3.2 | 4.1 | 4.3 |
- RELATED SCREW LISTS:
- Hexagon Socket Countersunk Cap Screw
- DIN7991 Hex Socket Countersunk Cap Screw
- ISO10642 Hex Socket Countersunk Cap Screw
- ASME B 18.3F Hexagon Socket Countersunk Screw
- Hexagon Socket Cap Screw
- DIN912 Hexagon Socket Cap Screw
- ASME B18.3 Hexagon Socket Cap Screw
- DIN6912 Hexagon Socket Cap Screw
- DIN7984 Low Head Socket Cap Screw
Mechanical Property
Carbon and Alloy Steel DIN7991 Screw— ISO 898-1
DIN 7991 countersunk socket head screws made from carbon and alloy steel are available in different property classes, including 8.8, 10.9 and 12.9, depending on the specified requirements. ISO 898-1 defines their mechanical and physical properties, including tensile strength, yield strength, proof load and hardness. The appropriate property class should be selected according to the required clamping force and service conditions.
Stainless Steel DIN7991 Screw— ISO 3506-1
For stainless steel DIN 7991 countersunk socket head screws, ISO 3506-1 specifies mechanical properties according to the stainless steel grade and property class. Common options include A2-70 and A4-70, depending on the required strength and corrosion resistance. Relevant properties include tensile strength and 0.2% proof stress, with requirements varying according to the specified grade, property class and applicable dimensions.