{"title":"DIN 125A \/ ISO 7089 \/ GB\/T 97.1 Flat Washers — 300HV Hardened Carbon Steel, Zinc CR3","description":"\u003ch1\u003eDIN 125A \/ ISO 7089 \/ GB\/T 97.1 Flat Washers — 300HV Hardened Carbon Steel, Zinc CR3\u003c\/h1\u003e\n\n\u003cp\u003eFULLERKREG DIN 125A 300HV hardened flat washers are manufactured from carbon steel 45# (C45 \/ S45C) with quench and temper heat treatment to achieve a minimum hardness of 300 HV, finished with a Zinc CR3 (trivalent chromium passivation, RoHS compliant) electroplated surface. Conforming to DIN 125A, ISO 7089, and GB\/T 97.1, these hardened washers combine the high bearing-face hardness required for Grade 8.8, 10.9, and 12.9 high-tensile bolts with the corrosion protection of a zinc electroplated coating — making them the preferred choice for structural, automotive, and outdoor industrial applications.\u003c\/p\u003e\n\n\u003cp\u003eThe Zinc CR3 surface finish provides a bright silver appearance with a thin trivalent chromium passivation layer (CR3, RoHS compliant — no hexavalent chromium Cr6+), offering salt spray resistance of ≥ 240 hours to red rust and significantly better corrosion protection than black oxide alone. The 300 HV minimum hardness per ISO 7089 ensures the washer bearing face resists embedding under high clamping loads, maintaining accurate bolt preload throughout the service life of the joint.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003e⚠️ Important:\u003c\/strong\u003e Always use hardened washers (300 HV minimum) with Grade 10.9 and Grade 12.9 bolts. Standard soft washers (≤ 200 HV) will embed under high clamping loads and cause preload loss in high-strength bolted joints.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eProduct Specifications\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eStandard\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eDIN 125A ≡ ISO 7089 ≡ GB\/T 97.1\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eType\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eHardened flat washer — normal series (Form A), chamfer on one side of inner hole\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMaterial\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCarbon Steel 45# (C45 \/ S45C \/ 1.0503)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eHeat Treatment\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eQuenched \u0026amp; Tempered (Q\u0026amp;T)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eHardness\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e300 – 370 HV (min. 300 HV per ISO 7089 hardened washer specification)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSurface Finish\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eZinc CR3 — electroplated zinc with trivalent chromium passivation (RoHS compliant)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eZinc Coating Thickness\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e5 – 8 μm (electroplated)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSalt Spray Resistance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e≥ 240 hours to red rust (per ISO 9227)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eRoHS Compliance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eYes — CR3 trivalent chromium, no Cr6+ hexavalent chromium\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSize Range\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eM5 – M36\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eRecommended Bolt Grade\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eGrade 8.8, 10.9, 12.9 high-tensile bolts\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCorrosion Resistance\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eGood — suitable for general industrial and mild outdoor environments\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMagnetic\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eYes\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 7089 (hardened washer grade)  |  GB\/T 97.1  |  DIN 125B (ISO 7090, double chamfer)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eProduct Gallery\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n      \u003ctd style=\"width:25%; text-align:center; padding:12px;\"\u003e[Product Photo 1]\u003c\/td\u003e\n      \u003ctd style=\"width:25%; text-align:center; padding:12px;\"\u003e[Product Photo 2]\u003c\/td\u003e\n      \u003ctd style=\"width:25%; text-align:center; padding:12px;\"\u003e[Product Photo 3]\u003c\/td\u003e\n      \u003ctd style=\"width:25%; text-align:center; padding:12px;\"\u003e[Product Photo 4]\u003c\/td\u003e\n    \u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eDimensions — DIN 125A \/ ISO 7089 \/ GB\/T 97.1\u003c\/h2\u003e\n\u003cp\u003eAll dimensions in millimeters (mm). Data per DIN 125A \/ ISO 7089 standard.\u003c\/p\u003e\n\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eNominal Size (Bolt d)\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      \u003cth\u003eWeight (kg \/ 1000 pcs)\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\u003e5.3\u003c\/td\u003e\n\u003ctd\u003e10\u003c\/td\u003e\n\u003ctd\u003e1.0\u003c\/td\u003e\n\u003ctd\u003e0.27\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\u003e12\u003c\/td\u003e\n\u003ctd\u003e1.6\u003c\/td\u003e\n\u003ctd\u003e0.68\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\u003e16\u003c\/td\u003e\n\u003ctd\u003e1.6\u003c\/td\u003e\n\u003ctd\u003e1.21\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\u003e20\u003c\/td\u003e\n\u003ctd\u003e2.0\u003c\/td\u003e\n\u003ctd\u003e2.37\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\u003e24\u003c\/td\u003e\n\u003ctd\u003e2.5\u003c\/td\u003e\n\u003ctd\u003e4.73\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\u003e28\u003c\/td\u003e\n\u003ctd\u003e2.5\u003c\/td\u003e\n\u003ctd\u003e6.43\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\u003e30\u003c\/td\u003e\n\u003ctd\u003e3.0\u003c\/td\u003e\n\u003ctd\u003e8.98\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM18\u003c\/td\u003e\n\u003ctd\u003e19.0\u003c\/td\u003e\n\u003ctd\u003e34\u003c\/td\u003e\n\u003ctd\u003e3.0\u003c\/td\u003e\n\u003ctd\u003e11.8\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\u003e37\u003c\/td\u003e\n\u003ctd\u003e3.0\u003c\/td\u003e\n\u003ctd\u003e14.2\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM22\u003c\/td\u003e\n\u003ctd\u003e23.0\u003c\/td\u003e\n\u003ctd\u003e39\u003c\/td\u003e\n\u003ctd\u003e3.0\u003c\/td\u003e\n\u003ctd\u003e15.6\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM24\u003c\/td\u003e\n\u003ctd\u003e25.0\u003c\/td\u003e\n\u003ctd\u003e44\u003c\/td\u003e\n\u003ctd\u003e4.0\u003c\/td\u003e\n\u003ctd\u003e27.4\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM27\u003c\/td\u003e\n\u003ctd\u003e28.0\u003c\/td\u003e\n\u003ctd\u003e50\u003c\/td\u003e\n\u003ctd\u003e4.0\u003c\/td\u003e\n\u003ctd\u003e35.9\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM30\u003c\/td\u003e\n\u003ctd\u003e31.0\u003c\/td\u003e\n\u003ctd\u003e56\u003c\/td\u003e\n\u003ctd\u003e4.0\u003c\/td\u003e\n\u003ctd\u003e45.4\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM33\u003c\/td\u003e\n\u003ctd\u003e34.0\u003c\/td\u003e\n\u003ctd\u003e60\u003c\/td\u003e\n\u003ctd\u003e5.0\u003c\/td\u003e\n\u003ctd\u003e64.3\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM36\u003c\/td\u003e\n\u003ctd\u003e37.0\u003c\/td\u003e\n\u003ctd\u003e66\u003c\/td\u003e\n\u003ctd\u003e5.0\u003c\/td\u003e\n\u003ctd\u003e83.2\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cem\u003e* d1 = inner diameter (clearance hole); d2 = outer diameter; h = nominal thickness. All dimensions per DIN 125A \/ ISO 7089. Weights are approximate based on carbon steel density (7.85 g\/cm³). Zinc CR3 coating (5–8μm) adds negligible weight.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eZinc CR3 vs Black Oxide — Surface Finish Comparison\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eProperty\u003c\/th\u003e\n      \u003cth\u003eZinc CR3 (This Product)\u003c\/th\u003e\n      \u003cth\u003eBlack Oxide\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eProcess\u003c\/td\u003e\n\u003ctd\u003eElectroplated zinc + trivalent chromium passivation\u003c\/td\u003e\n\u003ctd\u003eAlkaline blackening (conversion coating)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCoating thickness\u003c\/td\u003e\n\u003ctd\u003e5 – 8 μm\u003c\/td\u003e\n\u003ctd\u003e1 – 2 μm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSalt spray resistance\u003c\/td\u003e\n\u003ctd\u003e≥ 240 hours to red rust\u003c\/td\u003e\n\u003ctd\u003e≤ 24 hours (oil-wetted)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCorrosion protection\u003c\/td\u003e\n\u003ctd\u003eGood — cathodic zinc protection\u003c\/td\u003e\n\u003ctd\u003eMinimal — oil-dependent\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eRoHS compliance\u003c\/td\u003e\n\u003ctd\u003eYes (CR3 trivalent)\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eAppearance\u003c\/td\u003e\n\u003ctd\u003eBright silver \/ light blue iridescent\u003c\/td\u003e\n\u003ctd\u003eMatte black\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eOutdoor suitability\u003c\/td\u003e\n\u003ctd\u003eGood — general industrial \u0026amp; mild outdoor\u003c\/td\u003e\n\u003ctd\u003ePoor — indoor \/ oil-wetted only\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eBest for\u003c\/td\u003e\n\u003ctd\u003eStructural, automotive, outdoor industrial\u003c\/td\u003e\n\u003ctd\u003eIndoor machinery, precision equipment\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003e300HV Hardened vs Standard 200HV Washers\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eProperty\u003c\/th\u003e\n      \u003cth\u003e300HV Hardened (This Product)\u003c\/th\u003e\n      \u003cth\u003eStandard 200HV (Soft)\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eHardness\u003c\/td\u003e\n\u003ctd\u003e300 – 370 HV\u003c\/td\u003e\n\u003ctd\u003e≤ 200 HV\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eHeat treatment\u003c\/td\u003e\n\u003ctd\u003eQuenched \u0026amp; Tempered\u003c\/td\u003e\n\u003ctd\u003eNone (as-stamped)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eEmbedding under load\u003c\/td\u003e\n\u003ctd\u003eMinimal — maintains preload\u003c\/td\u003e\n\u003ctd\u003eSignificant — causes preload loss\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSuitable bolt grades\u003c\/td\u003e\n\u003ctd\u003e8.8, 10.9, 12.9\u003c\/td\u003e\n\u003ctd\u003e4.6, 4.8, 5.6, 6.8 (low-strength only)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eISO 7089 grade\u003c\/td\u003e\n\u003ctd\u003eHardened washer (300 HV)\u003c\/td\u003e\n\u003ctd\u003eNormal washer (200 HV)\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eMaterial \u0026amp; Mechanical Properties\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n\u003cth\u003eProperty\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eBase Material\u003c\/td\u003e\n\u003ctd\u003eCarbon Steel 45# (C45 \/ S45C \/ 1.0503)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCarbon Content\u003c\/td\u003e\n\u003ctd\u003e0.42 – 0.50%\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eHeat Treatment\u003c\/td\u003e\n\u003ctd\u003eQuenched \u0026amp; Tempered (Q\u0026amp;T)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eHardness\u003c\/td\u003e\n\u003ctd\u003e300 – 370 HV (min. 300 HV per ISO 7089)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eTensile Strength (approx.)\u003c\/td\u003e\n\u003ctd\u003e≥ 950 MPa (corresponding to 300 HV)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSurface Finish\u003c\/td\u003e\n\u003ctd\u003eZinc CR3 — electroplated zinc + trivalent chromium passivation\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eZinc Coating Thickness\u003c\/td\u003e\n\u003ctd\u003e5 – 8 μm\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSalt Spray Resistance\u003c\/td\u003e\n\u003ctd\u003e≥ 240 hours to red rust (ISO 9227)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eRoHS Compliance\u003c\/td\u003e\n\u003ctd\u003eYes — CR3 trivalent chromium, no Cr6+\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eTemperature Limit\u003c\/td\u003e\n\u003ctd\u003eUp to +120°C (zinc coating service limit)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eMagnetic\u003c\/td\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eDensity\u003c\/td\u003e\n\u003ctd\u003e7.85 g\/cm³\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eTypical Applications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e🏗️ \u003cstrong\u003eStructural steel construction\u003c\/strong\u003e — hardened washers under bolt heads and nuts in high-strength structural bolted connections (Grade 8.8 \/ 10.9), with Zinc CR3 providing corrosion protection for outdoor exposure\u003c\/li\u003e\n  \u003cli\u003e🚗 \u003cstrong\u003eAutomotive \u0026amp; transportation\u003c\/strong\u003e — chassis, suspension, body, and drivetrain bolted connections with Grade 10.9 fasteners; Zinc CR3 meets automotive RoHS requirements\u003c\/li\u003e\n  \u003cli\u003e🏭 \u003cstrong\u003eIndustrial plant \u0026amp; equipment\u003c\/strong\u003e — outdoor and semi-outdoor structural fastening where both hardness and corrosion protection are required\u003c\/li\u003e\n  \u003cli\u003e⚡ \u003cstrong\u003eElectrical infrastructure\u003c\/strong\u003e — transmission towers, switchgear, and electrical enclosure structural fastening\u003c\/li\u003e\n  \u003cli\u003e🛣️ \u003cstrong\u003eHighway \u0026amp; road infrastructure\u003c\/strong\u003e — guardrails, sign gantries, lighting columns, and road furniture with high-strength fasteners\u003c\/li\u003e\n  \u003cli\u003e🔧 \u003cstrong\u003eGeneral mechanical assembly\u003c\/strong\u003e — any high-strength bolted joint requiring both preload stability and corrosion resistance in a single washer\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 Zinc CR3 and why is it RoHS compliant?\u003c\/strong\u003e\u003cbr\u003e\nA: Zinc CR3 refers to electroplated zinc with a trivalent chromium (Cr3+) passivation layer. Traditional zinc plating used hexavalent chromium (Cr6+) passivation, which is toxic and restricted under the EU RoHS Directive and REACH regulations. CR3 trivalent chromium passivation provides similar corrosion protection without the environmental and health hazards of Cr6+. FULLERKREG Zinc CR3 washers are fully RoHS compliant.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Why do I need hardened washers with Grade 10.9 or 12.9 bolts?\u003c\/strong\u003e\u003cbr\u003e\nA: High-strength bolts generate very high contact pressures under the bolt head and nut — often exceeding 1000 MPa. Standard soft washers (≤ 200 HV) will plastically deform (embed) under these pressures, causing the bolt to lose preload. Hardened washers (300 HV minimum) resist embedding and maintain accurate preload throughout the service life of the joint. This is critical for structural integrity and joint reliability.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Can I use Zinc CR3 hardened washers outdoors?\u003c\/strong\u003e\u003cbr\u003e\nA: Yes. The Zinc CR3 coating provides ≥ 240 hours salt spray resistance (ISO 9227), making these washers suitable for general industrial and mild outdoor environments. For long-term outdoor structural applications or coastal environments, consider hot dip galvanised (HDG) washers for superior corrosion protection (45–85 μm zinc vs 5–8 μm for electroplated).\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What is the difference between DIN 125A 300HV Zinc CR3 and 300HV Black Oxide?\u003c\/strong\u003e\u003cbr\u003e\nA: Both products use the same 300HV hardened carbon steel 45# base material with identical dimensions. The difference is the surface finish: Zinc CR3 provides ≥ 240 hours salt spray resistance and is suitable for outdoor use; Black Oxide provides minimal corrosion protection and is best for indoor, oil-wetted, or precision applications. Choose Zinc CR3 for outdoor or corrosive environments; choose Black Oxide for indoor precision machinery.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What is the difference between DIN 125A and ISO 7089 for hardened washers?\u003c\/strong\u003e\u003cbr\u003e\nA: DIN 125A and ISO 7089 specify the same washer dimensions. ISO 7089 additionally defines two hardness grades: 200 HV (normal) and 300 HV (hardened). FULLERKREG 300HV Zinc CR3 washers conform to the ISO 7089 hardened washer specification and DIN 125A dimensional requirements.\u003c\/p\u003e","products":[],"url":"https:\/\/www.fullerkr.com\/collections\/din-125a-iso-7089-gb-t-97-1-flat-washer-300hv-zinc-cr3.oembed","provider":"Fullerkreg Fasteners","version":"1.0","type":"link"}