{"title":"Flanged Hexagon Bolts (DIN 6921) - Marine Stainless Steel (A4)","description":"\u003ch1\u003eFlanged Hexagon Bolts (DIN 6921) — Marine Stainless Steel A4 (SUS316) | FULLERKREG\u003c\/h1\u003e\n\n\u003cp\u003eFULLERKREG DIN 6921 Flanged Hexagon Bolts are precision-engineered fasteners combining a standard hexagon head with an integrated load-distributing flange. Manufactured from \u003cstrong\u003eA4 marine-grade stainless steel (SUS316)\u003c\/strong\u003e to strength class \u003cstrong\u003eA4-70\u003c\/strong\u003e, these bolts deliver outstanding corrosion resistance in the most demanding environments — including offshore, marine, chemical processing, and coastal construction applications.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eTwo Flange Head Variants\u003c\/h2\u003e\n\n\u003cp\u003eThis collection offers both standard configurations as defined by DIN 6921:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNon-Serrated Flanged (Smooth Flange)\u003c\/strong\u003e — A flat, smooth bearing surface beneath the head. Ideal for applications requiring easy disassembly, use with soft or coated surfaces, or where flange serrations could damage the mating material. Provides uniform load distribution without surface marking.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSerrated Flanged\u003c\/strong\u003e — Features radial serrations on the underside of the flange that bite into the mating surface upon tightening. This mechanical locking action significantly improves vibration resistance and prevents self-loosening, making it the preferred choice for dynamic load applications, automotive, and machinery assemblies.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eMaterial \u0026amp; Grade Specification\u003c\/h2\u003e\n\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eProperty\u003c\/th\u003e\n      \u003cth\u003eSpecification\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMaterial Grade\u003c\/td\u003e\n      \u003ctd\u003eA4 (SUS316 \/ 1.4401)\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eStrength Class\u003c\/td\u003e\n      \u003ctd\u003eA4-70\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMin. Tensile Strength\u003c\/td\u003e\n      \u003ctd\u003e700 MPa\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMin. 0.2% Proof Stress\u003c\/td\u003e\n      \u003ctd\u003e450 MPa\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMin. Elongation\u003c\/td\u003e\n      \u003ctd\u003e20%\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eHardness (max.)\u003c\/td\u003e\n      \u003ctd\u003e220 HV\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eChromium Content\u003c\/td\u003e\n      \u003ctd\u003e16.0–18.5%\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eNickel Content\u003c\/td\u003e\n      \u003ctd\u003e10.0–14.0%\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eMolybdenum Content\u003c\/td\u003e\n      \u003ctd\u003e2.0–3.0%\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eSurface Finish\u003c\/td\u003e\n      \u003ctd\u003eNatural \/ Passivated\u003c\/td\u003e\n    \u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cp\u003eThe addition of \u003cstrong\u003e2–3% molybdenum\u003c\/strong\u003e in A4\/SUS316 provides superior resistance to chloride-induced pitting and crevice corrosion compared to standard A2\/SUS304 — making it the material of choice for marine, coastal, and chemical environments.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eDimensional Standards — DIN 6921\u003c\/h2\u003e\n\n\u003cp\u003eAll FULLERKREG DIN 6921 bolts are manufactured and inspected in full conformance with the DIN 6921 dimensional standard and DIN 267-11 for mechanical properties of stainless steel fasteners.\u003c\/p\u003e\n\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eThread Size\u003c\/th\u003e\n      \u003cth\u003ePitch (mm)\u003c\/th\u003e\n      \u003cth\u003eWidth Across Flats s (mm)\u003c\/th\u003e\n      \u003cth\u003eFlange Diameter dc (mm)\u003c\/th\u003e\n      \u003cth\u003eHead Height k (mm)\u003c\/th\u003e\n      \u003cth\u003eWrench Size\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM5\u003c\/td\u003e\n\u003ctd\u003e0.8\u003c\/td\u003e\n\u003ctd\u003e8\u003c\/td\u003e\n\u003ctd\u003e14.2\u003c\/td\u003e\n\u003ctd\u003e3.5\u003c\/td\u003e\n\u003ctd\u003e8 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM6\u003c\/td\u003e\n\u003ctd\u003e1.0\u003c\/td\u003e\n\u003ctd\u003e10\u003c\/td\u003e\n\u003ctd\u003e17.0\u003c\/td\u003e\n\u003ctd\u003e4.0\u003c\/td\u003e\n\u003ctd\u003e10 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM8\u003c\/td\u003e\n\u003ctd\u003e1.25\u003c\/td\u003e\n\u003ctd\u003e13\u003c\/td\u003e\n\u003ctd\u003e22.0\u003c\/td\u003e\n\u003ctd\u003e5.5\u003c\/td\u003e\n\u003ctd\u003e13 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM10\u003c\/td\u003e\n\u003ctd\u003e1.5\u003c\/td\u003e\n\u003ctd\u003e15 (16)\u003c\/td\u003e\n\u003ctd\u003e27.0\u003c\/td\u003e\n\u003ctd\u003e6.5\u003c\/td\u003e\n\u003ctd\u003e15\/16 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM12\u003c\/td\u003e\n\u003ctd\u003e1.75\u003c\/td\u003e\n\u003ctd\u003e18\u003c\/td\u003e\n\u003ctd\u003e32.0\u003c\/td\u003e\n\u003ctd\u003e8.0\u003c\/td\u003e\n\u003ctd\u003e18 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM14\u003c\/td\u003e\n\u003ctd\u003e2.0\u003c\/td\u003e\n\u003ctd\u003e21\u003c\/td\u003e\n\u003ctd\u003e37.0\u003c\/td\u003e\n\u003ctd\u003e9.0\u003c\/td\u003e\n\u003ctd\u003e21 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM16\u003c\/td\u003e\n\u003ctd\u003e2.0\u003c\/td\u003e\n\u003ctd\u003e24\u003c\/td\u003e\n\u003ctd\u003e43.0\u003c\/td\u003e\n\u003ctd\u003e10.0\u003c\/td\u003e\n\u003ctd\u003e24 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM20\u003c\/td\u003e\n\u003ctd\u003e2.5\u003c\/td\u003e\n\u003ctd\u003e30\u003c\/td\u003e\n\u003ctd\u003e53.0\u003c\/td\u003e\n\u003ctd\u003e12.5\u003c\/td\u003e\n\u003ctd\u003e30 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cp\u003e\u003cem\u003eAll threads are metric coarse per ISO 261 \/ DIN 13. Tolerances per ISO 4759-1, property class 6g for external threads.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eKey Features \u0026amp; Benefits\u003c\/h2\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eIntegrated Flange:\u003c\/strong\u003e Eliminates the need for a separate washer — the built-in flange distributes clamping load over a larger bearing area, reducing surface pressure and the risk of joint relaxation.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMarine-Grade Corrosion Resistance:\u003c\/strong\u003e A4 (SUS316) with molybdenum resists saltwater, chlorides, acids, and industrial chemicals far beyond standard stainless grades.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eA4-70 Strength:\u003c\/strong\u003e Higher proof load than standard A4-50, suitable for structurally demanding connections without sacrificing corrosion performance.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVibration Resistance (Serrated variant):\u003c\/strong\u003e Serrated flange underside locks against the mating surface, preventing loosening under dynamic or cyclic loads.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNon-Magnetic:\u003c\/strong\u003e Austenitic SUS316 is essentially non-magnetic in the annealed condition — suitable for sensitive electronic or instrumentation environments.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHygienic \u0026amp; Low-Maintenance:\u003c\/strong\u003e Passivated surface is easy to clean and does not require painting, plating, or ongoing corrosion treatment.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFull DIN 6921 Compliance:\u003c\/strong\u003e Manufactured to exact dimensional and mechanical property requirements for interchangeability and engineering confidence.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eTypical Applications\u003c\/h2\u003e\n\n\u003cul\u003e\n  \u003cli\u003eMarine \u0026amp; offshore structures, boat fittings, dock hardware\u003c\/li\u003e\n  \u003cli\u003eCoastal and waterfront construction\u003c\/li\u003e\n  \u003cli\u003eChemical processing plants and pipework flanges\u003c\/li\u003e\n  \u003cli\u003eFood processing and pharmaceutical equipment\u003c\/li\u003e\n  \u003cli\u003eAutomotive and heavy machinery (serrated variant for vibration resistance)\u003c\/li\u003e\n  \u003cli\u003eHVAC, plumbing, and water treatment systems\u003c\/li\u003e\n  \u003cli\u003eArchitectural metalwork in corrosive environments\u003c\/li\u003e\n  \u003cli\u003eElectrical enclosures and instrumentation panels\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eStandards \u0026amp; Compliance\u003c\/h2\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDIN 6921\u003c\/strong\u003e — Hexagon bolts with flange (dimensional standard)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDIN 267-11 \/ ISO 3506-1\u003c\/strong\u003e — Mechanical properties of stainless steel bolts and screws\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eISO 261\u003c\/strong\u003e — Metric thread series\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eISO 4759-1\u003c\/strong\u003e — Tolerances for fasteners\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eEN ISO 898-1\u003c\/strong\u003e — Reference standard for mechanical properties (informational context for property class marking)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eCorrosion Resistance Comparison\u003c\/h2\u003e\n\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eEnvironment\u003c\/th\u003e\n      \u003cth\u003eA2 (SUS304)\u003c\/th\u003e\n      \u003cth\u003eA4 (SUS316) — This Product\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eFresh water\u003c\/td\u003e\n\u003ctd\u003e✓ Excellent\u003c\/td\u003e\n\u003ctd\u003e✓ Excellent\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eMild atmospheric\u003c\/td\u003e\n\u003ctd\u003e✓ Excellent\u003c\/td\u003e\n\u003ctd\u003e✓ Excellent\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCoastal \/ salt air\u003c\/td\u003e\n\u003ctd\u003e△ Moderate\u003c\/td\u003e\n\u003ctd\u003e✓ Excellent\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSeawater \/ marine immersion\u003c\/td\u003e\n\u003ctd\u003e✗ Limited\u003c\/td\u003e\n\u003ctd\u003e✓ Good\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eChloride solutions\u003c\/td\u003e\n\u003ctd\u003e✗ Poor\u003c\/td\u003e\n\u003ctd\u003e✓ Good\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eDilute acids\u003c\/td\u003e\n\u003ctd\u003e△ Moderate\u003c\/td\u003e\n\u003ctd\u003e✓ Good\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eChemical processing\u003c\/td\u003e\n\u003ctd\u003e✗ Not recommended\u003c\/td\u003e\n\u003ctd\u003e✓ Suitable\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eMarking \u0026amp; Identification\u003c\/h2\u003e\n\n\u003cp\u003eIn accordance with DIN 267-11 and ISO 3506-1, FULLERKREG DIN 6921 A4-70 bolts are marked on the head with:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eA4-70\u003c\/strong\u003e — Material and strength class designation\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFULLERKREG manufacturer mark\u003c\/strong\u003e — Traceable to production batch\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eMarking may be omitted on sizes below M5 where head geometry does not permit legible stamping.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003ePackaging \u0026amp; Supply\u003c\/h2\u003e\n\n\u003cul\u003e\n  \u003cli\u003eAvailable in standard retail packs, bulk bags, and full-box quantities\u003c\/li\u003e\n  \u003cli\u003eEach pack clearly labeled with: Part number, Thread size, Length, Material grade (A4-70), Standard (DIN 6921), and Flange type (Serrated \/ Non-Serrated)\u003c\/li\u003e\n  \u003cli\u003eCustom packaging and private-label options available for wholesale and OEM customers\u003c\/li\u003e\n  \u003cli\u003eCertificates of conformance (CoC) and material test reports (MTR) available on request\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What is the difference between A4-70 and A4-80?\u003c\/strong\u003e\u003cbr\u003eA: A4-70 has a minimum tensile strength of 700 MPa and proof stress of 450 MPa. A4-80 offers higher strength (800 MPa \/ 640 MPa) but is less commonly stocked. For most marine and structural applications, A4-70 provides an excellent balance of strength and corrosion resistance. FULLERKREG supplies A4-70 as the standard grade for DIN 6921.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Can I use these bolts in direct seawater immersion?\u003c\/strong\u003e\u003cbr\u003eA: A4 (SUS316) performs well in seawater and marine splash zones. For prolonged full immersion in stagnant seawater or high-chloride environments, additional engineering assessment is recommended. Crevice corrosion risk should be considered in tight joints.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Do I need a washer with a flanged bolt?\u003c\/strong\u003e\u003cbr\u003eA: Generally no — the integrated flange acts as a built-in washer, distributing load and protecting the mating surface. However, a separate washer may still be used on very soft materials or where surface protection is critical.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Which variant should I choose — serrated or non-serrated?\u003c\/strong\u003e\u003cbr\u003eA: Choose \u003cstrong\u003eserrated\u003c\/strong\u003e when vibration resistance and self-locking are priorities (machinery, automotive, dynamic loads). Choose \u003cstrong\u003enon-serrated\u003c\/strong\u003e when easy disassembly, surface protection, or use with soft\/coated materials is required.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Are these RoHS and REACH compliant?\u003c\/strong\u003e\u003cbr\u003eA: Yes. FULLERKREG A4 stainless steel fasteners do not contain restricted substances under RoHS or REACH regulations. Documentation available on request.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003cp\u003e\u003cem\u003eFULLERKREG — Precision Fasteners for Demanding Environments. All products manufactured and inspected to international standards. For technical support, custom specifications, or volume pricing, please contact our sales team.\u003c\/em\u003e\u003c\/p\u003e","products":[],"url":"https:\/\/www.fullerkr.com\/collections\/flanged-hexagon-bolts-din-6921-marine-stainless-steel-a4.oembed","provider":"Fullerkreg Fasteners","version":"1.0","type":"link"}