{"title":"DIN 433 Small OD Flat Washers — A4 Marine Stainless Steel (SUS316), Whitened \u0026 Passivated","description":"\u003ch1\u003eDIN 433 Small OD Flat Washers — A4 Marine Stainless Steel (SUS316), Whitened \u0026amp; Passivated\u003c\/h1\u003e\n\u003cp\u003eFULLERKREG DIN 433 A4 flat washers are manufactured from A4 stainless steel (SUS316) with a whitened and passivated surface finish. DIN 433 specifies a \u003cstrong\u003esmall outer diameter\u003c\/strong\u003e washer designed for use with countersunk screws, socket head cap screws in counterbored holes, and confined-space applications where standard DIN 125A washers are too large.\u003c\/p\u003e\n\u003cp\u003eA4 (SUS316) contains 2–3% molybdenum (Mo), giving a PREN of ~24–26 vs ~18–20 for A2 (SUS304) — providing significantly superior resistance to chloride pitting and crevice corrosion. This makes A4 DIN 433 washers the definitive choice for marine, offshore, coastal, and chemical environments where A2 may suffer pitting corrosion.\u003c\/p\u003e\n\n\u003ch2\u003eProduct Specifications\u003c\/h2\u003e\n\u003ctable\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eStandard\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eDIN 433 (Small OD flat washer) ≡ ISO 7092\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMaterial\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eA4 Stainless Steel \/ SUS316 \/ 1.4401\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSurface Finish\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eWhitened \u0026amp; Passivated\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSize Range\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eM1.6 – M20\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOD Characteristic\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSmall OD — fits within counterbores and confined spaces\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eHardness\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e≤ 200 HV\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTensile Strength\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e≥ 515 MPa (A4-70)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePREN\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e~24–26 (vs ~18–20 for A2 SUS304)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCorrosion Resistance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eExcellent — superior chloride pitting \u0026amp; crevice corrosion resistance vs A2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMagnetic\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSlightly magnetic after cold working\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eRelated Standard\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eISO 7092  |  DIN 125A A4 (standard OD)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\n\n\u003ch2\u003eProduct Gallery\u003c\/h2\u003e\n\u003ctable\u003e\u003ctbody\u003e\u003ctr\u003e\n\u003ctd style=\"width:25%;text-align:center;padding:12px\"\u003e[Photo 1]\u003c\/td\u003e\n\u003ctd style=\"width:25%;text-align:center;padding:12px\"\u003e[Photo 2]\u003c\/td\u003e\n\u003ctd style=\"width:25%;text-align:center;padding:12px\"\u003e[Photo 3]\u003c\/td\u003e\n\u003ctd style=\"width:25%;text-align:center;padding:12px\"\u003e[Photo 4]\u003c\/td\u003e\n\u003c\/tr\u003e\u003c\/tbody\u003e\u003c\/table\u003e\n\n\u003ch2\u003eDimensions — DIN 433 \/ ISO 7092\u003c\/h2\u003e\n\u003cp\u003eAll dimensions in mm. Dimensions identical for A2 and A4 grades.\u003c\/p\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eNominal Size\u003c\/th\u003e\n\u003cth\u003ed1 — Inner Ø (mm)\u003c\/th\u003e\n\u003cth\u003ed2 — Outer Ø (mm)\u003c\/th\u003e\n\u003cth\u003eh — Thickness (mm)\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eM1.6\u003c\/td\u003e\n\u003ctd\u003e1.7\u003c\/td\u003e\n\u003ctd\u003e3.5\u003c\/td\u003e\n\u003ctd\u003e0.3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM2\u003c\/td\u003e\n\u003ctd\u003e2.2\u003c\/td\u003e\n\u003ctd\u003e4.5\u003c\/td\u003e\n\u003ctd\u003e0.3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM2.5\u003c\/td\u003e\n\u003ctd\u003e2.7\u003c\/td\u003e\n\u003ctd\u003e5.0\u003c\/td\u003e\n\u003ctd\u003e0.5\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM3\u003c\/td\u003e\n\u003ctd\u003e3.2\u003c\/td\u003e\n\u003ctd\u003e6.0\u003c\/td\u003e\n\u003ctd\u003e0.5\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM3.5\u003c\/td\u003e\n\u003ctd\u003e3.7\u003c\/td\u003e\n\u003ctd\u003e7.0\u003c\/td\u003e\n\u003ctd\u003e0.5\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM4\u003c\/td\u003e\n\u003ctd\u003e4.3\u003c\/td\u003e\n\u003ctd\u003e8.0\u003c\/td\u003e\n\u003ctd\u003e0.5\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM5\u003c\/td\u003e\n\u003ctd\u003e5.3\u003c\/td\u003e\n\u003ctd\u003e9.0\u003c\/td\u003e\n\u003ctd\u003e1.0\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM6\u003c\/td\u003e\n\u003ctd\u003e6.4\u003c\/td\u003e\n\u003ctd\u003e11.0\u003c\/td\u003e\n\u003ctd\u003e1.6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM8\u003c\/td\u003e\n\u003ctd\u003e8.4\u003c\/td\u003e\n\u003ctd\u003e15.0\u003c\/td\u003e\n\u003ctd\u003e1.6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM10\u003c\/td\u003e\n\u003ctd\u003e10.5\u003c\/td\u003e\n\u003ctd\u003e18.0\u003c\/td\u003e\n\u003ctd\u003e1.6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM12\u003c\/td\u003e\n\u003ctd\u003e13.0\u003c\/td\u003e\n\u003ctd\u003e20.0\u003c\/td\u003e\n\u003ctd\u003e2.0\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM14\u003c\/td\u003e\n\u003ctd\u003e15.0\u003c\/td\u003e\n\u003ctd\u003e24.0\u003c\/td\u003e\n\u003ctd\u003e2.5\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM16\u003c\/td\u003e\n\u003ctd\u003e17.0\u003c\/td\u003e\n\u003ctd\u003e27.0\u003c\/td\u003e\n\u003ctd\u003e2.5\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM20\u003c\/td\u003e\n\u003ctd\u003e21.0\u003c\/td\u003e\n\u003ctd\u003e34.0\u003c\/td\u003e\n\u003ctd\u003e3.0\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cem\u003e* d1 = inner diameter; d2 = outer diameter; h = thickness. All per DIN 433 \/ ISO 7092.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003eA4 (SUS316) vs A2 (SUS304) — Why Choose A4?\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eProperty\u003c\/th\u003e\n\u003cth\u003eA4 — SUS316 (This Product)\u003c\/th\u003e\n\u003cth\u003eA2 — SUS304\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eMolybdenum (Mo)\u003c\/td\u003e\n\u003ctd\u003e2.0 – 3.0%\u003c\/td\u003e\n\u003ctd\u003eNone\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePREN\u003c\/td\u003e\n\u003ctd\u003e~24–26\u003c\/td\u003e\n\u003ctd\u003e~18–20\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eChloride pitting resistance\u003c\/td\u003e\n\u003ctd\u003eExcellent\u003c\/td\u003e\n\u003ctd\u003eGood\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCrevice corrosion resistance\u003c\/td\u003e\n\u003ctd\u003eVery good\u003c\/td\u003e\n\u003ctd\u003eModerate\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMarine \/ offshore suitability\u003c\/td\u003e\n\u003ctd\u003eYes — preferred grade\u003c\/td\u003e\n\u003ctd\u003eLimited in high-chloride\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTensile strength\u003c\/td\u003e\n\u003ctd\u003e≥ 515 MPa\u003c\/td\u003e\n\u003ctd\u003e≥ 500 MPa\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCost\u003c\/td\u003e\n\u003ctd\u003eHigher (Mo content)\u003c\/td\u003e\n\u003ctd\u003eStandard\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBest for\u003c\/td\u003e\n\u003ctd\u003eMarine, coastal, offshore, chemical, food-grade\u003c\/td\u003e\n\u003ctd\u003eGeneral outdoor, architectural, mild corrosive\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eDIN 433 vs DIN 125A — Small OD vs Standard OD\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eProperty\u003c\/th\u003e\n\u003cth\u003eDIN 433 (This Product)\u003c\/th\u003e\n\u003cth\u003eDIN 125A (Standard OD)\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eOD characteristic\u003c\/td\u003e\n\u003ctd\u003eSmall — fits within counterbores\u003c\/td\u003e\n\u003ctd\u003eStandard — general purpose\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM8 outer diameter\u003c\/td\u003e\n\u003ctd\u003e15.0 mm\u003c\/td\u003e\n\u003ctd\u003e16.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM10 outer diameter\u003c\/td\u003e\n\u003ctd\u003e18.0 mm\u003c\/td\u003e\n\u003ctd\u003e20.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM12 outer diameter\u003c\/td\u003e\n\u003ctd\u003e20.0 mm\u003c\/td\u003e\n\u003ctd\u003e24.0 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBest for\u003c\/td\u003e\n\u003ctd\u003eCountersunk screws, counterbores, confined spaces\u003c\/td\u003e\n\u003ctd\u003eGeneral fastening, load distribution\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eISO equivalent\u003c\/td\u003e\n\u003ctd\u003eISO 7092\u003c\/td\u003e\n\u003ctd\u003eISO 7089\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eMaterial Properties — A4 \/ SUS316\u003c\/h2\u003e\n\u003ctable\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDesignation\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eA4 \/ SUS316 \/ 1.4401 \/ 0Cr17Ni12Mo2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCr Content\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e16.0 – 18.0%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eNi Content\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e10.0 – 14.0%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMo Content\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e2.0 – 3.0% — key differentiator vs A2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTensile Strength\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e≥ 515 MPa (annealed)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eHardness\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e≤ 200 HV\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePREN\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e~24–26\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDensity\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e7.98 g\/cm³\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTemperature Range\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e−50°C to +300°C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMagnetic\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSlightly magnetic after cold working\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\n\n\u003ch2\u003eTypical Applications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e🚢 \u003cstrong\u003eMarine \u0026amp; offshore fastening\u003c\/strong\u003e — A4 is the mandatory grade for marine countersunk fastening; small OD fits within countersink recesses on boat fittings, deck hardware, and offshore structures\u003c\/li\u003e\n\u003cli\u003e🌊 \u003cstrong\u003eCoastal \u0026amp; salt-air environments\u003c\/strong\u003e — superior chloride resistance for coastal architectural hardware, cladding, and outdoor structures in high-salinity areas\u003c\/li\u003e\n\u003cli\u003e🔩 \u003cstrong\u003eCountersunk screws in marine applications\u003c\/strong\u003e — small OD allows flush seating of countersunk screws in marine timber, GRP, and composite panels\u003c\/li\u003e\n\u003cli\u003e🍼 \u003cstrong\u003eFood \u0026amp; pharmaceutical equipment\u003c\/strong\u003e — A4 SUS316 preferred grade for hygienic applications; small OD for compact fastening in equipment panels and covers\u003c\/li\u003e\n\u003cli\u003e🧲 \u003cstrong\u003eChemical plant fastening\u003c\/strong\u003e — superior resistance to chloride-containing process environments; small OD for confined-space fastening in chemical equipment\u003c\/li\u003e\n\u003cli\u003e🏭 \u003cstrong\u003ePrecision machinery — corrosive environments\u003c\/strong\u003e — small OD for counterbored and confined-space fastening in machinery exposed to corrosive media\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eFAQ\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Why choose A4 over A2 for DIN 433 washers?\u003c\/strong\u003e\u003cbr\u003eA: A4 (SUS316) contains 2–3% molybdenum, giving PREN ~24–26 vs ~18–20 for A2 (SUS304). In practice, A4 resists chloride pitting and crevice corrosion significantly better — making it the preferred choice for marine, coastal, offshore, and chemical environments. Choose A4 when the application involves salt water, salt air, or chloride-containing media.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What is the difference between DIN 433 and DIN 125A?\u003c\/strong\u003e\u003cbr\u003eA: DIN 433 has a smaller outer diameter than DIN 125A for the same bolt size (e.g. M10: DIN 433 d2 = 18 mm vs DIN 125A d2 = 20 mm). DIN 433 is designed for countersunk screws and confined spaces; DIN 125A is the general-purpose standard washer. Both have the same inner diameter for the same bolt size.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What is the ISO equivalent of DIN 433?\u003c\/strong\u003e\u003cbr\u003eA: DIN 433 is equivalent to ISO 7092 (small washer series). DIN 433 is the German national standard; ISO 7092 is the international equivalent.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Are A4 DIN 433 washers suitable for seawater immersion?\u003c\/strong\u003e\u003cbr\u003eA: A4 (SUS316) provides significantly better seawater resistance than A2. For splash zone and above-waterline marine applications, A4 is the correct choice. For continuous seawater immersion, even A4 can suffer crevice corrosion in stagnant conditions — specify Duplex 2205 for fully immersed applications.\u003c\/p\u003e","products":[],"url":"https:\/\/www.fullerkr.com\/collections\/din-433-small-o-d-flat-washer-a4-stainless.oembed","provider":"Fullerkreg Fasteners","version":"1.0","type":"link"}