{"title":"DIN 7991 Flat Head Countersunk Socket Cap Screw Grade 10.9 Zinc CR3","description":"\u003ch2\u003eFULLERKREG DIN 7991 \/ ISO 10642 Grade 10.9 Zinc CR3 Flat Head Countersunk Socket Cap Screws\u003c\/h2\u003e\n\u003cp\u003eFULLERKREG DIN 7991 \/ ISO 10642 Grade 10.9 Zinc CR3 Flat Head Countersunk Socket Cap Screws are high-strength fasteners featuring a 90° countersunk flat head with a hexagon socket drive. Manufactured from 10B21 boron-alloyed steel with an electroplated zinc CR3 (trivalent chromate) surface treatment, these screws combine Grade 10.9 tensile strength (min. 1,040 MPa) with a flush-fit profile, reliable corrosion resistance, and full RoHS environmental compliance. The bright silver zinc finish provides a professional appearance while the countersunk head sits flush with or below the mating surface, making these screws ideal for high-strength, RoHS-regulated, and corrosion-exposed flush-fit applications.\u003c\/p\u003e\n\n\u003ch2\u003eProduct Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandards:\u003c\/strong\u003e DIN 7991 \/ ISO 10642\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStrength Grade:\u003c\/strong\u003e 10.9 (heat treated)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e 10B21 boron-alloyed steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTensile Strength:\u003c\/strong\u003e Min. 1,040 MPa\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eYield Strength:\u003c\/strong\u003e Min. 940 MPa\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHardness:\u003c\/strong\u003e HRC 32–39\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHead Type:\u003c\/strong\u003e Flat countersunk head, 90° included angle\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSurface Treatment:\u003c\/strong\u003e Zinc electroplating with CR3 trivalent chromate passivation\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlating Thickness:\u003c\/strong\u003e Typically 5–12 μm zinc\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSalt Spray Resistance:\u003c\/strong\u003e 24–48 hrs (per ISO 9227)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRoHS Compliance:\u003c\/strong\u003e ✅ Fully compliant — CR3 trivalent chromate contains no hexavalent chromium (Cr6+)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Type:\u003c\/strong\u003e Metric coarse, full thread\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThread Tolerance:\u003c\/strong\u003e 6g\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDrive Type:\u003c\/strong\u003e Hexagon socket (Allen key \/ hex key)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSizes Available:\u003c\/strong\u003e M3 – M20\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eRoHS Compliance — CR3 Trivalent Chromate Zinc Plating\u003c\/h2\u003e\n\u003cp\u003eThe zinc CR3 coating uses \u003cstrong\u003etrivalent chromium (Cr3+)\u003c\/strong\u003e passivation, replacing the traditional hexavalent chromium (Cr6+) process. This is essential for compliance with international environmental regulations:\u003c\/p\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eRegulation\u003c\/th\u003e\n\u003cth\u003eRequirement\u003c\/th\u003e\n\u003cth\u003eCR3 Zinc Compliance\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eEU RoHS Directive (2011\/65\/EU)\u003c\/td\u003e\n\u003ctd\u003eNo hexavalent chromium (Cr6+)\u003c\/td\u003e\n\u003ctd\u003e✅ Compliant\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEU REACH Regulation\u003c\/td\u003e\n\u003ctd\u003eNo SVHC restricted substances\u003c\/td\u003e\n\u003ctd\u003e✅ Compliant\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eELV Directive (2000\/53\/EC)\u003c\/td\u003e\n\u003ctd\u003eNo Cr6+ in vehicle components\u003c\/td\u003e\n\u003ctd\u003e✅ Compliant\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eChina RoHS (GB\/T 26572)\u003c\/td\u003e\n\u003ctd\u003eNo restricted hazardous substances\u003c\/td\u003e\n\u003ctd\u003e✅ Compliant\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eSurface Finish Comparison — Zinc CR3 vs Black Oxide\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eProperty\u003c\/th\u003e\n\u003cth\u003eZinc CR3 (This Page)\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\u003eAppearance\u003c\/td\u003e\n\u003ctd\u003eBright silver\u003c\/td\u003e\n\u003ctd\u003eMatte black\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCoating thickness\u003c\/td\u003e\n\u003ctd\u003e5–12 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\u003cstrong\u003e24–48 hrs\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eLow (without oil)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRoHS compliance\u003c\/td\u003e\n\u003ctd\u003e✅ Compliant (CR3)\u003c\/td\u003e\n\u003ctd\u003e✅ Compliant\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCountersink fit impact\u003c\/td\u003e\n\u003ctd\u003eMinimal (5–12 μm)\u003c\/td\u003e\n\u003ctd\u003eNegligible (1–2 μm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBest for\u003c\/td\u003e\n\u003ctd\u003eOutdoor, humid, RoHS-regulated applications\u003c\/td\u003e\n\u003ctd\u003eIndoor, general industrial\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePrice\u003c\/td\u003e\n\u003ctd\u003e🔵 Slightly higher\u003c\/td\u003e\n\u003ctd\u003e🟢 Economy\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eMaterial — 10B21 Boron Steel Chemical Composition (%)\u003c\/h2\u003e\n\u003cp\u003eFULLERKREG DIN 7991 Grade 10.9 Zinc CR3 countersunk screws are manufactured from 10B21 boron-alloyed steel. The addition of boron (B) significantly improves hardenability, enabling Grade 10.9 mechanical properties with a leaner alloy composition. All values are maximum unless a range is indicated.\u003c\/p\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eGrade\u003c\/th\u003e\n\u003cth\u003eC\u003c\/th\u003e\n\u003cth\u003eSi (max)\u003c\/th\u003e\n\u003cth\u003eMn\u003c\/th\u003e\n\u003cth\u003eP (max)\u003c\/th\u003e\n\u003cth\u003eS (max)\u003c\/th\u003e\n\u003cth\u003eB\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e10B21\u003c\/td\u003e\n\u003ctd\u003e0.18–0.23\u003c\/td\u003e\n\u003ctd\u003e≤0.30\u003c\/td\u003e\n\u003ctd\u003e0.80–1.10\u003c\/td\u003e\n\u003ctd\u003e≤0.030\u003c\/td\u003e\n\u003ctd\u003e≤0.030\u003c\/td\u003e\n\u003ctd\u003e0.0005–0.003\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eMechanical Properties — Grade 10.9 (ISO 898-1)\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eProperty\u003c\/th\u003e\n\u003cth\u003eRequirement\u003c\/th\u003e\n\u003cth\u003eUnit\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eTensile Strength (Rm)\u003c\/td\u003e\n\u003ctd\u003eMin. 1,040\u003c\/td\u003e\n\u003ctd\u003eMPa\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eYield Strength \/ Proof Load Stress (Rp0.2)\u003c\/td\u003e\n\u003ctd\u003eMin. 940\u003c\/td\u003e\n\u003ctd\u003eMPa\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCore Hardness\u003c\/td\u003e\n\u003ctd\u003e32–39\u003c\/td\u003e\n\u003ctd\u003eHRC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Hardness (max)\u003c\/td\u003e\n\u003ctd\u003e≤44\u003c\/td\u003e\n\u003ctd\u003eHRC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eElongation after fracture (A)\u003c\/td\u003e\n\u003ctd\u003eMin. 9\u003c\/td\u003e\n\u003ctd\u003e%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eReduction of area (Z)\u003c\/td\u003e\n\u003ctd\u003eMin. 48\u003c\/td\u003e\n\u003ctd\u003e%\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImpact energy (KV) at room temp.\u003c\/td\u003e\n\u003ctd\u003eMin. 37\u003c\/td\u003e\n\u003ctd\u003eJ\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHead Angle\u003c\/td\u003e\n\u003ctd\u003e90°\u003c\/td\u003e\n\u003ctd\u003edegrees\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eThread Tolerance Class\u003c\/td\u003e\n\u003ctd\u003e6g\u003c\/td\u003e\n\u003ctd\u003e—\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSurface Treatment\u003c\/td\u003e\n\u003ctd\u003eZinc CR3 (trivalent chromate)\u003c\/td\u003e\n\u003ctd\u003e—\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e✅ RoHS \u0026amp; REACH Compliant\u003c\/strong\u003e — CR3 trivalent chromate zinc plating contains no hexavalent chromium (Cr6+), meeting EU RoHS, REACH, ELV, and China RoHS requirements\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlush-fit countersunk head\u003c\/strong\u003e — 90° flat head sits flush with or below the mating surface, eliminating protrusions for a clean, snag-free finish\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGrade 10.9 high strength\u003c\/strong\u003e — 1,040 MPa tensile strength, 49% stronger than A2-070 stainless (700 MPa)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eZinc CR3 coating\u003c\/strong\u003e — bright silver appearance with 24–48 hours salt spray resistance (ISO 9227)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e10B21 boron steel\u003c\/strong\u003e — excellent hardenability and consistent mechanical properties through heat treatment\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDIN 7991 \/ ISO 10642 dual standard\u003c\/strong\u003e — internationally recognized specification\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eISO\/TS16949 quality management\u003c\/strong\u003e — hardness test, tensile test, salt spray test, and PPAP report available on request\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eApplications\u003c\/h2\u003e\n\u003cp\u003eFULLERKREG DIN 7991 Grade 10.9 Zinc CR3 countersunk socket cap screws are widely used in high-strength, RoHS-regulated, and corrosion-exposed flush-fit applications:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eElectronics and electrical equipment (EU RoHS regulated) requiring flush fasteners\u003c\/li\u003e\n\u003cli\u003eAutomotive body panels and EV (electric vehicle) assemblies (ELV compliant)\u003c\/li\u003e\n\u003cli\u003eOutdoor machinery and equipment requiring corrosion-resistant flush fasteners\u003c\/li\u003e\n\u003cli\u003eRobotics and automation equipment in humid environments\u003c\/li\u003e\n\u003cli\u003eBicycle frames, motorcycle components, and sporting equipment\u003c\/li\u003e\n\u003cli\u003eConsumer electronics and home appliances with flush-fit requirements\u003c\/li\u003e\n\u003cli\u003eIndustrial fixtures and structural connections requiring flush fasteners\u003c\/li\u003e\n\u003cli\u003eAny application requiring Grade 10.9 countersunk screws with RoHS-compliant zinc plating\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eCountersunk Hole Requirements\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCountersink angle:\u003c\/strong\u003e 90° included angle (standard metric countersink)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCountersink diameter:\u003c\/strong\u003e Must match or slightly exceed the screw head diameter (dk) to allow flush seating\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlating note:\u003c\/strong\u003e Zinc CR3 plating (5–12 μm) has minimal effect on head dimensions. For precision countersink fits, verify head diameter after plating against your countersink diameter\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial consideration:\u003c\/strong\u003e In soft materials (aluminum, plastic), the countersink may deform under high torque — reduce torque or use a larger head diameter\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eDimensional Specifications — DIN 7991 \/ ISO 10642 (Unit: mm)\u003c\/h2\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eThread (d)\u003c\/th\u003e\n\u003cth\u003ePitch (p)\u003c\/th\u003e\n\u003cth\u003eHead Dia. dk Max.\u003c\/th\u003e\n\u003cth\u003eHead Dia. dk Min.\u003c\/th\u003e\n\u003cth\u003eHead Height k Max.\u003c\/th\u003e\n\u003cth\u003eHead Height k Min.\u003c\/th\u003e\n\u003cth\u003eKey Size s\u003c\/th\u003e\n\u003cth\u003eKey Depth t Min.\u003c\/th\u003e\n\u003cth\u003eBody Dia. ds Max.\u003c\/th\u003e\n\u003cth\u003eBody Dia. ds Min.\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eM3\u003c\/td\u003e\n\u003ctd\u003e0.5\u003c\/td\u003e\n\u003ctd\u003e6.72\u003c\/td\u003e\n\u003ctd\u003e6.48\u003c\/td\u003e\n\u003ctd\u003e1.86\u003c\/td\u003e\n\u003ctd\u003e1.66\u003c\/td\u003e\n\u003ctd\u003e2.0\u003c\/td\u003e\n\u003ctd\u003e1.1\u003c\/td\u003e\n\u003ctd\u003e3.00\u003c\/td\u003e\n\u003ctd\u003e2.86\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM4\u003c\/td\u003e\n\u003ctd\u003e0.7\u003c\/td\u003e\n\u003ctd\u003e8.96\u003c\/td\u003e\n\u003ctd\u003e8.62\u003c\/td\u003e\n\u003ctd\u003e2.48\u003c\/td\u003e\n\u003ctd\u003e2.18\u003c\/td\u003e\n\u003ctd\u003e2.5\u003c\/td\u003e\n\u003ctd\u003e1.5\u003c\/td\u003e\n\u003ctd\u003e4.00\u003c\/td\u003e\n\u003ctd\u003e3.82\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eM5\u003c\/td\u003e\n\u003ctd\u003e0.8\u003c\/td\u003e\n\u003ctd\u003e11.20\u003c\/td\u003e\n\u003ctd\u003e10.82\u003c\/td\u003e\n\u003ctd\u003e3.10\u003c\/td\u003e\n\u003ctd\u003e2.72\u003c\/td\u003e\n\u003ctd\u003e3.0\u003c\/td\u003e\n\u003ctd\u003e2.0\u003c\/td\u003e\n\u003ctd\u003e5.00\u003c\/td\u003e\n\u003ctd\u003e4.82\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\u003e13.44\u003c\/td\u003e\n\u003ctd\u003e13.02\u003c\/td\u003e\n\u003ctd\u003e3.72\u003c\/td\u003e\n\u003ctd\u003e3.32\u003c\/td\u003e\n\u003ctd\u003e4.0\u003c\/td\u003e\n\u003ctd\u003e2.5\u003c\/td\u003e\n\u003ctd\u003e6.00\u003c\/td\u003e\n\u003ctd\u003e5.82\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\u003e17.92\u003c\/td\u003e\n\u003ctd\u003e17.42\u003c\/td\u003e\n\u003ctd\u003e4.96\u003c\/td\u003e\n\u003ctd\u003e4.46\u003c\/td\u003e\n\u003ctd\u003e5.0\u003c\/td\u003e\n\u003ctd\u003e3.5\u003c\/td\u003e\n\u003ctd\u003e8.00\u003c\/td\u003e\n\u003ctd\u003e7.78\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\u003e22.40\u003c\/td\u003e\n\u003ctd\u003e21.82\u003c\/td\u003e\n\u003ctd\u003e6.20\u003c\/td\u003e\n\u003ctd\u003e5.52\u003c\/td\u003e\n\u003ctd\u003e6.0\u003c\/td\u003e\n\u003ctd\u003e4.4\u003c\/td\u003e\n\u003ctd\u003e10.00\u003c\/td\u003e\n\u003ctd\u003e9.78\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\u003e26.88\u003c\/td\u003e\n\u003ctd\u003e26.22\u003c\/td\u003e\n\u003ctd\u003e7.44\u003c\/td\u003e\n\u003ctd\u003e6.64\u003c\/td\u003e\n\u003ctd\u003e8.0\u003c\/td\u003e\n\u003ctd\u003e5.3\u003c\/td\u003e\n\u003ctd\u003e12.00\u003c\/td\u003e\n\u003ctd\u003e11.73\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\u003e33.60\u003c\/td\u003e\n\u003ctd\u003e32.82\u003c\/td\u003e\n\u003ctd\u003e8.80\u003c\/td\u003e\n\u003ctd\u003e7.90\u003c\/td\u003e\n\u003ctd\u003e10.0\u003c\/td\u003e\n\u003ctd\u003e6.8\u003c\/td\u003e\n\u003ctd\u003e16.00\u003c\/td\u003e\n\u003ctd\u003e15.73\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\u003e40.32\u003c\/td\u003e\n\u003ctd\u003e39.42\u003c\/td\u003e\n\u003ctd\u003e10.16\u003c\/td\u003e\n\u003ctd\u003e9.06\u003c\/td\u003e\n\u003ctd\u003e12.0\u003c\/td\u003e\n\u003ctd\u003e8.2\u003c\/td\u003e\n\u003ctd\u003e20.00\u003c\/td\u003e\n\u003ctd\u003e19.67\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What is the difference between Zinc CR3 and traditional yellow zinc (Cr6+)?\u003c\/strong\u003e\u003cbr\u003e\nTraditional yellow zinc chromate uses hexavalent chromium (Cr6+), which is restricted under EU RoHS and REACH regulations. Zinc CR3 uses trivalent chromium (Cr3+), providing equivalent corrosion protection without any restricted substances. CR3 is the environmentally compliant replacement.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What countersink angle is required for DIN 7991 screws?\u003c\/strong\u003e\u003cbr\u003e\nDIN 7991 uses a 90° included angle countersink, which is the standard metric countersink angle. Ensure your countersink tool or pre-drilled hole uses a 90° angle for correct flush seating.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does the zinc CR3 plating affect the countersink fit?\u003c\/strong\u003e\u003cbr\u003e\nZinc CR3 plating is 5–12 μm thick, which has minimal but non-negligible effect on head dimensions compared to black oxide (1–2 μm). For precision countersink fits, verify the plated head diameter against your countersink diameter before assembly.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Can I get RoHS compliance documentation?\u003c\/strong\u003e\u003cbr\u003e\nYes. FULLERKREG provides RoHS compliance declarations, PPAP reports, material certificates, and test reports upon request for all zinc CR3 plated products.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What corrosion resistance does Zinc CR3 provide?\u003c\/strong\u003e\u003cbr\u003e\nZinc CR3 plating provides 24–48 hours of salt spray resistance (per ISO 9227) before red rust appears, depending on plating thickness.\u003c\/p\u003e\n\n\u003ch2\u003ePackaging \u0026amp; Availability\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eStandard sizes M3 – M20 available in stock\u003c\/li\u003e\n\u003cli\u003eBulk carton packaging; small box and custom packaging available\u003c\/li\u003e\n\u003cli\u003eRoHS compliance documentation and material certificates available on request\u003c\/li\u003e\n\u003cli\u003ePPAP report and test reports available on request\u003c\/li\u003e\n\u003cli\u003eCustom lengths accepted for large orders\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eDownload Specification\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0054\/6317\/9375\/files\/DIN7991.pdf?v=1779087760\" title=\"DIN 7991 ISO 10642 Countersunk Socket Cap Screw Dimensional Specification PDF\"\u003eDIN 7991 \/ ISO 10642 — Full Dimensional Specification (PDF)\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0054\/6317\/9375\/files\/ISO898-1.pdf?v=1779071673\" title=\"ISO 898-1 Mechanical Properties of Fasteners\"\u003eISO 898-1 — Mechanical Properties of Fasteners (PDF)\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eQuality Assurance\u003c\/h2\u003e\n\u003cp\u003eAll FULLERKREG DIN 7991 Grade 10.9 Zinc CR3 countersunk socket cap screws are manufactured under strict quality control procedures including:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eRockwell hardness test (HRC 32–39)\u003c\/li\u003e\n\u003cli\u003eTensile strength test (min. 1,040 MPa)\u003c\/li\u003e\n\u003cli\u003eSalt spray corrosion test (zinc CR3, 24–48 hrs per ISO 9227)\u003c\/li\u003e\n\u003cli\u003eRoHS substance verification — no hexavalent chromium (Cr6+)\u003c\/li\u003e\n\u003cli\u003eHead angle verification (90° countersink)\u003c\/li\u003e\n\u003cli\u003eDimensional inspection per DIN 7991 \/ ISO 10642\u003c\/li\u003e\n\u003cli\u003eChemical composition analysis (10B21, B content verified)\u003c\/li\u003e\n\u003cli\u003ePPAP documentation available upon request\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eFor wholesale pricing, bulk orders, RoHS documentation, or technical inquiries, please \u003ca href=\"\/pages\/contact-us\"\u003econtact our sales team\u003c\/a\u003e.\u003c\/p\u003e","products":[],"url":"https:\/\/www.fullerkr.com\/collections\/din-7991-flat-head-countersunk-socket-cap-screw-grade-10-9-zinc-cr3.oembed","provider":"Fullerkreg Fasteners","version":"1.0","type":"link"}