Hex Flange Bolts
| Standard | DIN 6921 · ISO 4162 · SAE J429 |
|---|---|
| Material | 10B21 / SCM435 / 35CrMo |
| Strength Grade | 8.8 / 10.9 / 12.9 |
| Size Range | M5-M16 |
| Surface Treatment | Zinc Plated / Geomet |
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Product Description
Product Description & Key Specifications
Hex flange bolts combine a hex head with an integrated flange bearing surface, reducing the need for a separate washer in many automotive, EV, machinery and bracket assemblies. This range covers DIN 6921, ISO 4162 and SAE J429 references in 10B21, SCM435 and 35CrMo with 8.8 / 10.9 / 12.9 grades.
Flange bolts are selected where assembly speed, bearing area, washer elimination and controlled clamp load matter. Serrated or non-serrated flange form, thread length, under-head geometry, coating, grade marking and mating nut type should be confirmed because flange bolts are often used in automated assembly and vibration-loaded equipment.
Zinc plated finish is common for general automotive and machinery use, while Geomet coating is specified where higher corrosion performance and controlled coating thickness are required. Common RFQs include M6, M8, M10, M12 and M16 flange bolts with flange nuts or weld nuts.
| Product type | Hex flange bolts / automotive flange bolts |
|---|---|
| Standards | DIN 6921 / ISO 4162 / SAE J429 |
| Material | 10B21 / SCM435 / 35CrMo |
| Strength grade | 8.8 / 10.9 / 12.9 |
| Size range | M5-M16 |
| Common models | M6 x 16, M8 x 25, M10 x 30, M12 x 40, M14 x 45, M16 x 50 |
| Thread type | Metric thread, full or partial thread by drawing |
| Surface finish | Zinc plated / Geomet |
| Matched hardware | Hex flange nuts, hex nuts, weld nuts and washers where specified |
| Documentation | MTC, CoC, hardness, tensile, coating and dimensional report on request |
Dimensions & SpecificationsDIN 6921 / ISO 4162
Technical Drawing
Dimensional Table
| Parameter | M5 | M6 | M8 | M10 | M12 | M14 | M16 | M20 |
|---|---|---|---|---|---|---|---|---|
| P | 0.8 | 1 | 1|1.25 | 1|1.25|1.5 | 1.25|1.5|1.75 | 1.5|2 | 1.5|2 | 1.5|2.5 |
| da/max | 5.7 | 6.8 | 9.2 | 11.2 | 13.7 | 15.7 | 17.7 | 22.4 |
| dc/max | 11.8 | 14.2 | 18 | 22.3 | 26.6 | 30.5 | 35 | 43 |
| ds/max | 5 | 6 | 8 | 10 | 12 | 14 | 16 | 20 |
| ds/min | 4.82 | 5.82 | 7.78 | 9.78 | 11.73 | 13.73 | 15.73 | 19.67 |
| e/min | 8.71 | 10.95 | 14.26 | 16.5 | 17.62 | 19.86 | 23.15 | 29.87 |
| Lf/max | 1.4 | 2 | 2 | 2 | 3 | 3 | 3 | 4 |
| k/max | 5.4 | 6.6 | 8.1 | 9.2 | 11.5 | 12.8 | 14.4 | 17.1 |
| r/min | 0.25 | 0.4 | 0.4 | 0.4 | 0.6 | 0.6 | 0.6 | 0.8 |
| s/max | 8 | 10 | 13 | 15 | 16 | 18 | 21 | 27 |
| s/min | 7.78 | 9.78 | 12.73 | 14.73 | 15.73 | 17.73 | 20.67 | 26.67 |
Engineering references
Technical resources
Review the applicable dimensions, drawing and standard relationship before confirming the ordered specification.02
Selection
Selection Advantages by Application
Automotive and EV Brackets
M6-M12 zinc plated or Geomet flange bolts are common for brackets, battery trays, body hardware and chassis accessories where washer-free assembly improves speed.
Automotive and EV fastenersMachinery Frames and Guards
10.9 / 12.9 flange bolts in SCM435 or 35CrMo support machinery guards, frames and service panels where a broad bearing surface is useful.
Industrial equipment fastenersRail and Transit Equipment
Flange bolts can be used in selected rail vehicle brackets and panels when grade, coating and vibration requirements are confirmed by the project.
Railway fasteners03
Assembly
Recommended Matching Products
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Manufacturing
Manufacturing & Quality Control
Manufacturing CapabilityQuality Control
Cold heading and flange head forming for M5-M16 bolts10B21 / SCM435 / 35CrMo material verification
Thread rolling and heat treatment for 8.8 / 10.9 / 12.9 gradesHardness, tensile and thread gauge inspection by lot
Serrated or non-serrated flange geometry by drawingFlange diameter, head height, under-head and thread length checks
Zinc plating or Geomet coatingCoating thickness, corrosion test support and visual inspection
Bulk, carton or line-side automotive packagingCoC, dimensional and coating reports prepared on request
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FAQ
Common Questions Before RFQ
What are hex flange bolts used for?
They are used where an integrated bearing flange can replace a separate washer and speed up automotive, machinery or bracket assembly.
What is the difference between serrated and non-serrated flange bolts?
Serrated flange bolts add bite against the mating surface, while non-serrated flange bolts provide bearing area without teeth. The drawing should define the form.
Which coating should I choose?
Zinc plated is common for general use, while Geomet is selected for higher corrosion performance and controlled coating thickness.
Can grade 12.9 flange bolts be supplied?
Yes, grade 12.9 can be supplied when material, heat treatment and project requirements are confirmed.
Can matching flange nuts be supplied?
Yes. Flange bolts can be supplied with DIN 6923 / ISO 4161 hex flange nuts or other specified hardware.
Need hex flange bolts for automotive or machinery assemblies?
Send standard, size, length, flange type, grade, coating, quantity and matching nut requirement. We can quote DIN 6921 / ISO 4162 flange bolts in zinc plated or Geomet finish.
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