DIN7991 Countersunk Socket Bolt Specifications
Parameter | Details |
Product Name | DIN7991 Countersunk Socket Head Bolt / Flat Head Allen Screw |
Standard | DIN7991 German Industrial Standard |
Strength Grade | Carbon Steel: 8.8/10.9/12.9; Stainless Steel: A2-70(304), A4-70(316) |
Structural Feature | 60° Countersunk Flat Head, Internal Hex Drive, Fully Flush Hidden Installation |
Thread Tolerance | 6G Precision Metric Thread, Standard Tolerance & Strong Interchangeability |
Surface Finish | Black Oxide, Electro-galvanized Zinc, Dacromet, Stainless Steel Polish |
Size Range | M3-M24 Full Sizes In Stock, Custom Non-standard Length Available |
Application | Automation Equipment, Precision Mold, Sheet Metal Cabinet, Electrical Equipment, Tooling Fixture, Medical Devices |
Certification | ISO9001, Material Test Report, Hardness & Torque Test, Salt Spray Report, Batch Quality Certificate |
Package | Standard Export Carton & Pallet, Custom Neutral Export Packaging Supported |
Delivery Time | 3-7 days for regular stock sizes, 15-25 days for bulk and customized orders |
DIN7991 Product Core Advantages
Flush Hidden Installation, Smooth & Safe Surface
Adopting standard 60° countersunk flat head design, the bolt head can be completely embedded into the workpiece after installation without protruding parts. It effectively avoids scratch and collision problems, ensuring smooth and beautiful equipment surface. It is the best choice for hidden fastening of equipment shells, sheet metal panels and precision appearance parts.
Full High-strength Grade Coverage for All Working Conditions
Covers Grade 8.8 general high-strength, Grade 10.9 medium heavy-duty, Grade 12.9 ultra-high strength carbon steel and 304/316 stainless steel anti-corrosion series. It can adapt from light-duty general assembly to heavy-duty mold locking and long-term vibration working conditions, realizing full-scenario application with one product series.
Hex Drive Design with High Locking Torque
The internal hexagon hole matches standard Allen wrenches and bits with uniform stress. It supports high-torque tightening, effectively preventing slipping, tooth breaking and slot slipping compared with cross screws. It provides stable locking performance for precision machinery and high-frequency vibration equipment.
Multiple Anti-corrosion Finishes for Indoor & Outdoor Use
Black oxide finish features high hardness and wear resistance for mold tooling. Electro-galvanized finish offers cost-effective basic rust resistance for indoor general equipment. Dacromet finish provides excellent high temperature resistance and salt spray performance. Stainless steel versions resist moisture, salt spray and acid-base corrosion, suitable for harsh outdoor and corrosive environments.
Grade 8.8 Countersunk Socket Bolt (General Industrial Type)
Made of high-quality medium carbon steel with quenching and tempering treatment, balancing hardness and toughness with high cost performance. With electro-galvanized or black oxide finish, it is widely used in ordinary automation equipment, sheet metal boxes, electrical cabinets and light-duty tooling fixtures, serving as the mainstream bulk model for industrial procurement.
Grade 10.9 High-strength Countersunk Bolt (Medium Heavy-duty Type)
Adopting 40Cr alloy steel with high-temperature tempering strengthening, it has excellent tensile resistance, fatigue resistance and impact resistance. Matched with Dacromet anti-corrosion coating, it is suitable for outdoor equipment, medium-sized molds, construction machinery parts and high-frequency vibration equipment assembly.
Grade 12.9 Ultra-high Strength Countersunk Bolt (Precision Heavy-duty Top Type)
Made of high-end 42CrMo alloy steel with fine tempering, it is the highest strength grade among civilian DIN standard countersunk screws. Featuring high hardness, wear resistance and stable deformation resistance, it is specially designed for precision molds, high-end automation equipment, heavy-duty tooling fixtures and core equipment load-bearing locking scenarios.
304 Stainless Steel Countersunk Bolt A2-70 (General Anti-corrosion Type)
Authentic 304 stainless steel with non-magnetic, anti-oxidation and anti-rust properties. It resists humid air, rain erosion and mild acid-base environment, widely applied in outdoor small equipment, garden machinery, water treatment equipment and damp workshop sheet metal assembly.
316 Stainless Steel Countersunk Bolt A4-70 (High-end Anti-corrosion Type)
Molybdenum-containing 316 stainless steel has far superior salt spray, acid and alkali corrosion resistance than 304 steel. It can adapt to extreme harsh working conditions such as coastal salt spray, chemical corrosion and high temperature and humidity, ideal for marine equipment, chemical machinery and high-end precision anti-corrosion equipment.
Production Process
Graded Material Selection: Select raw materials by carbon steel, alloy steel and stainless steel grades, strictly control material composition, and ensure stable mechanical performance of different grades from the source.
Precision Cold Heading Forming: One-piece automatic cold heading forming with standard countersunk radian, flat end surface and burr-free inner hex hole, ensuring high coaxiality accuracy.
High-precision Thread Rolling: Unified precision thread rolling process with full tooth profile and standard tolerance, ensuring smooth meshing and strong interchangeability.
Graded Heat Treatment: Exclusive tempering process for Grade 8.8/10.9/12.9 to accurately control hardness range and avoid brittle fracture, slipping and deformation.
Custom Anti-corrosion Treatment: Complete black oxide, electro-galvanizing, Dacromet and stainless steel polishing processes to meet different anti-rust and appearance requirements.
Full-batch Precision Inspection: Test dimension accuracy, inner hex matching degree, hardness, torque and salt spray performance batch by batch, conduct strict graded sorting and provide complete factory qualification reports.
Application Industries
Automation Equipment Manufacturing: Hidden fastening for automation frames, module accessories and transmission equipment.
Precision Mold & Tooling: Positioning and locking of mold inserts, jigs and fixtures (Grade 12.9 black type preferred).
Sheet Metal & Electrical Industry: Flat assembly of equipment shells, chassis cabinets and sheet metal panels for safer and more beautiful appearance.
Outdoor Mechanical Equipment: Anti-corrosion fastening of garden machinery, agricultural machinery and outdoor brackets (Dacromet/stainless steel type preferred).
High-end Precision Equipment: Precision assembly of medical devices, instruments, chemical and coastal anti-corrosion equipment.
Why Choose Our DIN7991 Countersunk Socket Bolts
We specialize in the production of DIN standard precision internal hex fasteners for many years, providing full series DIN7991 countersunk bolts including 8.8/10.9/12.9 high-strength carbon steel and 304/316 stainless steel versions, covering general, heavy-duty, precision and anti-corrosion full-scenario demands. All products are manufactured strictly in accordance with German standards with accurate dimensions, standard hole positions and stable locking performance. We have sufficient stock and support non-standard customization and special anti-corrosion processes. Complete mechanical, material and salt spray test reports are available, providing high-quality hidden precision fastening solutions for global equipment and engineering customers.
If you are looking for high-quality DIN7991 countersunk socket head bolts, Grade 8.8/10.9/12.9 flat head Allen screws and stainless steel hidden assembly bolts, feel free to contact us for professional technical support and accurate quotation.
