Hex Flange Nut | Serrated, Anti-Loosen, DIN6923, M6 & SAE

Walk any assembly line today and you’ll spot the quiet workhorse: the Hex Flange Nut. Specifically, the DIN6923 variant from Dongtantou North, Yongnian, Hebei, China has been popping up in my notebook more often. Why? Because manufacturers are shaving seconds (and washers) off every joint. The built-in flange spreads load, the serrations (when specified) bite just enough to resist loosening, and honestly, it’s a neat little upgrade over a standard hex nut plus washer combo.

Short description, in plain words: a hex nut with an integrated non-spinning washer. Simple, yes, but it’s reshaping fastening routines in automotive, rail, wind, and solar structures. Industry trend-wise, we’re seeing a steady pivot to zinc-nickel finishes for better corrosion resistance, and traceability is becoming non-negotiable—QR-coded lots, 3.1 material certs, the works. Many customers say they changed over mainly to cut rework on vibrating assemblies; seems fair.

DIN6923 Technical Snapshot

Parameter	Spec (≈ values; real-world use may vary)
Standards	DIN 6923, ISO 4161; mechanical per ISO 898-2; coatings per ISO 4042
Sizes	M5–M24 (others on request); thread ISO metric coarse
Materials	Carbon steel (C1022, 35#), alloy (40Cr), stainless A2-70 / A4-80
Property class	Class 6, 8, 10, 12; stainless A2/A4 to ISO 3506-2
Flange OD	≈ 1.8–2.4 × thread diameter (per DIN table)
Styles	Serrated (≈30° serrations) or non-serrated
Finishes	Clear/black zinc, Zn-Ni, HDG, Geomet/Dacromet, plain, passivated SS

Process, Testing, and Service Life

Materials → cold heading → flange forming → tapping → optional serration → heat treatment (quench & temper for 8/10/12) → coating → 100% thread gauge check → packing. QC includes hardness (ISO 6508), proof load (ISO 898-2), salt spray (ASTM B117), and dimensional checks (ISO 3269). Typical corrosion performance: zinc ≈ 72–120 h NSS, Zn-Ni ≈ 720–1000 h, Geomet ≈ 600–1200 h; HDG varies by mass. In service, inland structures might see ≈ 10–15 years with Zn-Ni; coastal A4-80 stainless does better—actually much better in splash zones.

Where Hex Flange Nut Shines

• Automotive assemblies: subframes, brackets—good vibration resistance with serrated flanges.
• Steel construction and rail: faster fit-up, fewer components.
• Wind and solar racking: broad flange spreads load on softer metals.
• Appliances and machinery: less risk of marring painted surfaces (go non-serrated).

Customization (from Yongnian suppliers)

• Marking/traceability: lot numbers, QR codes, PPAP up to Level 3 for automotive.
• Coating stack-ups tuned to torque-tension; target K-factors on request.
• Non-standard flange OD for thin-sheet applications; captive washer hybrids if needed.
• Packaging: small kits, line-side totes, rust inhibitor VCI bags.

Vendor Comparison (quick glance)

Vendor type	MOQ	Lead time	Certs	Customization	Notes
Local distributor	Low	1–3 days stock	Basic CoC	Limited	Great for urgent fills
Generic importers	Medium	2–6 weeks	ISO 9001 (varies)	Moderate	Watch consistency
Hebei Yongnian makers (incl. TBLS)	Flexible	2–4 weeks typical	ISO 9001, IATF 16949 (site-specific)	High	Good on PPAP, torque-tension tuning

Real-world notes, honestly

Case study 1: An automotive bracket program switched to serrated Hex Flange Nut class 10 with Zn-Ni. Assembly time dropped ≈ 8%, and torque audit failures fell under 0.3% over six months. Case study 2: A coastal solar site moved to A4-80 non-serrated to protect aluminum rails—no red rust after 1,000 h NSS; torque scatter tightened after lubricant spec change. Customers tell me the biggest surprise is fewer components to track. I guess simple wins.

Origin: Dongtantou North, Yongnian, Hebei, China. Compliance and documentation available on request: 3.1 certs, RoHS/REACH, PPAP, and test reports.

Authoritative references

1. DIN 6923: Hexagon nuts with flange, Deutsches Institut für Normung.
2. ISO 4161: Hexagon nuts with flange, International Organization for Standardization.
3. ISO 898-2: Mechanical properties of fasteners—Nuts, ISO.
4. ISO 4042: Fasteners—Electroplated coatings, ISO.
5. ASTM B117: Standard Practice for Operating Salt Spray (Fog) Apparatus, ASTM International.