{"title":"DIN 916 \/ ISO 4029 Socket Set Screw Cup Point A4 Stainless","description":"\u003ch2\u003eDIN 916 \/ ISO 4029 — Socket Set Screw with Cup Point | A4 Stainless Steel (Marine Grade)\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eBrand:\u003c\/strong\u003e FULLERKREG  |  \u003cstrong\u003eMaterial:\u003c\/strong\u003e A4 Stainless Steel (SUS316 \/ 1.4401)  |  \u003cstrong\u003eSurface:\u003c\/strong\u003e Passivated (Bright Finish)\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eProduct Overview\u003c\/h2\u003e\n\u003cp\u003eFULLERKREG DIN 916 \/ ISO 4029 Socket Set Screws with Cup Point in A4 Stainless Steel (SUS316) represent the premium stainless option for the most demanding corrosive environments. The addition of 2–3% molybdenum to the SUS316 alloy delivers significantly superior resistance to chloride-induced pitting and crevice corrosion compared to standard A2 (SUS304) — making A4 the material of choice for marine, offshore, chemical processing, and high-salinity industrial applications.\u003c\/p\u003e\n\u003cp\u003eThe cup point geometry — a concave spherical recess at the tip — provides reliable shaft locking, anti-rotation, and positioning performance. Combined with a bright passivated finish, these set screws deliver long-term reliability in environments where standard stainless or carbon steel fasteners would rapidly corrode.\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eStandards \u0026amp; Specifications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eStandards:\u003c\/strong\u003e DIN 916, ISO 4029\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Form:\u003c\/strong\u003e ISO Metric Coarse Thread (per ISO 68-1)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eThread Tolerance:\u003c\/strong\u003e 6g (per ISO 965-1)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDrive Type:\u003c\/strong\u003e Hexagon Socket (Allen \/ Hex Key)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePoint Type:\u003c\/strong\u003e Cup Point — concave spherical recess at tip\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e A4 Stainless Steel (SUS316 \/ 1.4401 \/ 316 SS)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial Grade:\u003c\/strong\u003e A4 per ISO 3506-3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSurface Treatment:\u003c\/strong\u003e Passivated — bright, clean finish with enhanced corrosion resistance\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eApplicable Standard for Mechanical Properties:\u003c\/strong\u003e ISO 3506-3\u003c\/li\u003e\n\u003c\/ul\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\u003cth\u003eStandard\u003c\/th\u003e\n\u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003eA4 Stainless Steel (SUS316 \/ 1.4401)\u003c\/td\u003e\n\u003ctd\u003eISO 3506-3\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eChemical Composition (Cr)\u003c\/td\u003e\n\u003ctd\u003e16.5 – 18.5%\u003c\/td\u003e\n\u003ctd\u003e—\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eChemical Composition (Ni)\u003c\/td\u003e\n\u003ctd\u003e10.0 – 13.0%\u003c\/td\u003e\n\u003ctd\u003e—\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eChemical Composition (Mo)\u003c\/td\u003e\n\u003ctd\u003e2.0 – 2.5%\u003c\/td\u003e\n\u003ctd\u003e—\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eMinimum Tensile Strength\u003c\/td\u003e\n\u003ctd\u003e700 MPa (A4-70)\u003c\/td\u003e\n\u003ctd\u003eISO 3506-3\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eHardness (typical)\u003c\/td\u003e\n\u003ctd\u003eHV 200 – 300\u003c\/td\u003e\n\u003ctd\u003eISO 3506-3\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eThread Tolerance\u003c\/td\u003e\n\u003ctd\u003e6g\u003c\/td\u003e\n\u003ctd\u003eISO 965-1\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSurface Treatment\u003c\/td\u003e\n\u003ctd\u003ePassivated (Bright \/ 洗白钝化)\u003c\/td\u003e\n\u003ctd\u003e—\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eMagnetic Properties\u003c\/td\u003e\n\u003ctd\u003eSlightly magnetic (work-hardened)\u003c\/td\u003e\n\u003ctd\u003e—\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eOperating Temperature\u003c\/td\u003e\n\u003ctd\u003e-196°C to +800°C (intermittent)\u003c\/td\u003e\n\u003ctd\u003e—\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cem\u003eNote: A4 stainless steel set screws are not hardened to the same level as alloy steel 45H\/12.9 grade. A4 is optimized for superior corrosion resistance, particularly in chloride-rich and marine environments. For maximum mechanical holding force on hardened shafts, alloy steel grade is recommended.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eWhy A4 (SUS316)? — The Role of Molybdenum\u003c\/h2\u003e\n\u003cp\u003eThe key differentiator of A4 (SUS316) over A2 (SUS304) is the addition of \u003cstrong\u003e2.0–2.5% Molybdenum (Mo)\u003c\/strong\u003e:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePitting resistance:\u003c\/strong\u003e Molybdenum dramatically increases resistance to chloride-induced pitting corrosion — the primary failure mode of A2 in marine and coastal environments.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCrevice corrosion resistance:\u003c\/strong\u003e Superior performance in tight joints, threaded connections, and under-head contact areas where oxygen depletion creates aggressive local chemistry.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHigher PREN value:\u003c\/strong\u003e Pitting Resistance Equivalent Number (PREN) for SUS316 is approximately 24–26, vs. 18–20 for SUS304 — a significant improvement in chloride tolerance.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAcid resistance:\u003c\/strong\u003e Better resistance to dilute sulfuric acid, phosphoric acid, and organic acids compared to A2.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eSurface Treatment: Passivation (洗白钝化)\u003c\/h2\u003e\n\u003cp\u003eAll FULLERKREG A4 stainless set screws undergo passivation treatment after manufacturing:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eProcess:\u003c\/strong\u003e Acid passivation (citric acid or nitric acid bath) removes free iron, machining residues, and surface contaminants.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eResult:\u003c\/strong\u003e A bright, clean, silver-white finish with a reinforced chromium-molybdenum oxide passive layer.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBenefit:\u003c\/strong\u003e Maximizes the inherent corrosion resistance of SUS316, especially critical in chloride environments where surface contamination can initiate pitting.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAppearance:\u003c\/strong\u003e Uniform bright metallic finish — no discoloration, no scale, no heat tint.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eDimensional Range\u003c\/h2\u003e\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\u003eSocket Size s (mm)\u003c\/th\u003e\n\u003cth\u003eLength Range (mm)\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\u003e1.5\u003c\/td\u003e\n\u003ctd\u003e3 – 16\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\u003e2.0\u003c\/td\u003e\n\u003ctd\u003e4 – 20\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\u003e2.5\u003c\/td\u003e\n\u003ctd\u003e5 – 25\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\u003e3.0\u003c\/td\u003e\n\u003ctd\u003e6 – 30\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\u003e4.0\u003c\/td\u003e\n\u003ctd\u003e8 – 40\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\u003e5.0\u003c\/td\u003e\n\u003ctd\u003e10 – 50\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\u003e6.0\u003c\/td\u003e\n\u003ctd\u003e12 – 60\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\u003e8.0\u003c\/td\u003e\n\u003ctd\u003e16 – 80\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\u003e10.0\u003c\/td\u003e\n\u003ctd\u003e20 – 100\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eM24\u003c\/td\u003e\n\u003ctd\u003e3.0\u003c\/td\u003e\n\u003ctd\u003e12.0\u003c\/td\u003e\n\u003ctd\u003e25 – 120\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cem\u003eCustom lengths and special configurations available upon request. Contact FULLERKREG for non-standard requirements.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eCup Point Geometry\u003c\/h2\u003e\n\u003cp\u003eThe cup point (concave spherical recess) is the defining feature of DIN 916 \/ ISO 4029 set screws:\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePositive mechanical lock:\u003c\/strong\u003e The rim of the cup bites into the shaft surface, resisting rotation and axial movement.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eReduced shaft damage:\u003c\/strong\u003e The concave geometry distributes contact stress more evenly than cone or dog points, minimizing shaft marring.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eVibration resistance:\u003c\/strong\u003e Reliable performance under dynamic and cyclic loads.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eRepositionable:\u003c\/strong\u003e Allows limited repositioning without severe shaft damage.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCorrosion-environment optimized:\u003c\/strong\u003e Ideal for stainless and non-ferrous shafts in marine, chemical, and wet environments.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eCorrosion Resistance of A4 Stainless Steel\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExcellent resistance\u003c\/strong\u003e to seawater, marine atmosphere, and coastal environments.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExcellent resistance\u003c\/strong\u003e to chloride solutions, brine, and de-icing salts.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExcellent resistance\u003c\/strong\u003e to dilute sulfuric acid, phosphoric acid, acetic acid, and many organic acids.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eGood resistance\u003c\/strong\u003e to food acids, alkalis, and most industrial chemicals.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSuperior to A2 (SUS304)\u003c\/strong\u003e in all chloride-containing environments due to molybdenum content.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNot recommended\u003c\/strong\u003e for strong oxidizing acids (e.g., concentrated nitric acid) or high-temperature halide environments without engineering review.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eTypical Applications\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eMarine and offshore equipment — deck hardware, rigging, underwater assemblies\u003c\/li\u003e\n  \u003cli\u003eCoastal and harbor infrastructure exposed to salt spray\u003c\/li\u003e\n  \u003cli\u003eChemical processing plants — pumps, valves, reactors, pipework\u003c\/li\u003e\n  \u003cli\u003eDesalination and water treatment equipment\u003c\/li\u003e\n  \u003cli\u003eFood and beverage processing — washdown and CIP (clean-in-place) environments\u003c\/li\u003e\n  \u003cli\u003ePharmaceutical manufacturing — sterile and high-purity environments\u003c\/li\u003e\n  \u003cli\u003eSwimming pool and aquatic facility equipment\u003c\/li\u003e\n  \u003cli\u003eOil \u0026amp; gas topside equipment and subsea assemblies\u003c\/li\u003e\n  \u003cli\u003eShaft-to-hub locking in corrosive or high-humidity environments\u003c\/li\u003e\n  \u003cli\u003eArchitectural hardware in coastal or high-pollution urban environments\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eMaterial Comparison — Selection Guide\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003cthead\u003e\n    \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\u003cth\u003eAlloy Steel 45H\/12.9\u003c\/th\u003e\n\u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCorrosion Resistance\u003c\/td\u003e\n\u003ctd\u003e✅ Superior (Mo-enhanced)\u003c\/td\u003e\n\u003ctd\u003e✅ Good\u003c\/td\u003e\n\u003ctd\u003e⚠️ Limited\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eChloride \/ Marine Resistance\u003c\/td\u003e\n\u003ctd\u003e✅ Excellent\u003c\/td\u003e\n\u003ctd\u003e⚠️ Moderate\u003c\/td\u003e\n\u003ctd\u003e❌ Poor\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eSurface Hardness\u003c\/td\u003e\n\u003ctd\u003eHV 200–300\u003c\/td\u003e\n\u003ctd\u003eHV 200–300\u003c\/td\u003e\n\u003ctd\u003eHRC 45–53\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eTensile Strength\u003c\/td\u003e\n\u003ctd\u003e700 MPa (A4-70)\u003c\/td\u003e\n\u003ctd\u003e700 MPa (A2-70)\u003c\/td\u003e\n\u003ctd\u003e1220 MPa (12.9)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eHolding Force on Hard Shafts\u003c\/td\u003e\n\u003ctd\u003e⚠️ Moderate\u003c\/td\u003e\n\u003ctd\u003e⚠️ Moderate\u003c\/td\u003e\n\u003ctd\u003e✅ Maximum\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eFood \/ Pharma Suitability\u003c\/td\u003e\n\u003ctd\u003e✅ Yes\u003c\/td\u003e\n\u003ctd\u003e✅ Yes\u003c\/td\u003e\n\u003ctd\u003e❌ No\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eMarine \/ Seawater Suitability\u003c\/td\u003e\n\u003ctd\u003e✅ Yes\u003c\/td\u003e\n\u003ctd\u003e⚠️ Limited\u003c\/td\u003e\n\u003ctd\u003e❌ No\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eAppearance\u003c\/td\u003e\n\u003ctd\u003eBright silver-white\u003c\/td\u003e\n\u003ctd\u003eBright silver-white\u003c\/td\u003e\n\u003ctd\u003eMatte black\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eCost\u003c\/td\u003e\n\u003ctd\u003ePremium\u003c\/td\u003e\n\u003ctd\u003eStandard\u003c\/td\u003e\n\u003ctd\u003eStandard\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eInstallation Guidelines\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eUse the correct hex key (Allen wrench) matching the socket size — refer to the dimensional table above.\u003c\/li\u003e\n  \u003cli\u003eEnsure the shaft and bore are clean and free of oil or debris before installation.\u003c\/li\u003e\n  \u003cli\u003eFor vibration-critical applications, apply a stainless-compatible thread-locking compound.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAnti-galling precaution (critical for stainless):\u003c\/strong\u003e A4 stainless steel is susceptible to galling (cold welding \/ thread seizure) during installation. Always apply a molybdenum disulfide (MoS₂) or nickel-based anti-seize compound to the threads before tightening.\u003c\/li\u003e\n  \u003cli\u003eTighten slowly and steadily using a calibrated torque wrench — avoid high-speed power tools which dramatically increase galling risk.\u003c\/li\u003e\n  \u003cli\u003eIf a fastener begins to seize during installation, back it off immediately and re-apply anti-seize before continuing.\u003c\/li\u003e\n  \u003cli\u003eDo not exceed the rated tightening torque for the thread size and A4-70 grade.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eQuality Assurance\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDimensional Inspection:\u003c\/strong\u003e 100% thread gauge inspection per ISO 965-1 (6g tolerance)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMaterial Verification:\u003c\/strong\u003e PMI (Positive Material Identification) \/ spectrometer analysis confirming SUS316 composition including Mo content\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHardness Testing:\u003c\/strong\u003e Vickers hardness test per ISO 3506-3\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eTensile \/ Proof Load Testing:\u003c\/strong\u003e Per ISO 3506-3 (A4-70)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSalt Spray Test:\u003c\/strong\u003e Extended corrosion resistance verification post-passivation\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSocket Torque Test:\u003c\/strong\u003e Drive socket integrity verification\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLot Traceability:\u003c\/strong\u003e Full material and process traceability per batch, with mill certificates available on request\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003ePackaging Options\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eBulk (polybag or carton) — standard for wholesale orders\u003c\/li\u003e\n  \u003cli\u003eSmall box (labeled, per size) — available for mixed or sample orders\u003c\/li\u003e\n  \u003cli\u003eCustom packaging — available for OEM and private-label customers\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eOrdering Information\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePrice:\u003c\/strong\u003e Unit price per piece (USD), not per thousand. Contact us for volume pricing.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCustomer Base:\u003c\/strong\u003e B2B wholesale only. We do not serve retail \/ B2C customers.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOrder Method:\u003c\/strong\u003e All orders are placed offline. Online prices are for reference and inquiry only. Please contact us via email to place orders.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMOQ:\u003c\/strong\u003e Varies by size — contact FULLERKREG for minimum order quantities.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLead Time (Small Batch):\u003c\/strong\u003e Approx. 30 days, delivered DDP.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLead Time (Large Volume):\u003c\/strong\u003e FOB Shanghai; other Incoterms negotiable.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMill Certificates:\u003c\/strong\u003e Available upon request for material traceability.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCustom Orders:\u003c\/strong\u003e Non-standard lengths, special configurations, or OEM requirements available upon request.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003chr\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What is the difference between DIN 916 and ISO 4029?\u003c\/strong\u003e\u003cbr\u003e\nA: DIN 916 is the German standard; ISO 4029 is the international equivalent. Both specify the same cup point set screw geometry and are dimensionally interchangeable. FULLERKREG products comply with both standards.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What does A4 stainless steel mean?\u003c\/strong\u003e\u003cbr\u003e\nA: A4 is the designation for molybdenum-bearing austenitic stainless steel per ISO 3506-3, corresponding to SUS316 \/ 1.4401 (16–18% Chromium, 10–13% Nickel, 2–2.5% Molybdenum). The molybdenum addition provides significantly superior resistance to chloride pitting and crevice corrosion compared to standard A2 (SUS304).\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What is the difference between A4 and A2 stainless steel?\u003c\/strong\u003e\u003cbr\u003e\nA: The key difference is the addition of 2.0–2.5% Molybdenum in A4 (SUS316). This dramatically improves resistance to chloride-induced pitting and crevice corrosion. A4 is the preferred choice for marine, seawater, chemical, and high-salinity environments where A2 may suffer pitting failure.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: What is passivation (洗白钝化)?\u003c\/strong\u003e\u003cbr\u003e\nA: Passivation is an acid treatment that removes free iron and surface contaminants, restoring and enhancing the natural chromium-molybdenum oxide passive layer on the stainless steel surface. The result is a bright, clean finish with maximized corrosion resistance.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Are A4 stainless set screws suitable for seawater immersion?\u003c\/strong\u003e\u003cbr\u003e\nA: A4 (SUS316) provides excellent resistance to seawater splash and marine atmosphere, and good resistance to intermittent seawater immersion. For continuous full seawater immersion under high stress, super-duplex or higher-alloy grades may be required. Contact FULLERKREG for engineering guidance on extreme marine applications.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Why do stainless steel set screws sometimes seize during installation?\u003c\/strong\u003e\u003cbr\u003e\nA: Stainless steel is prone to galling (cold welding) due to its tendency to work-harden under friction. Always apply a molybdenum disulfide (MoS₂) or nickel-based anti-seize compound to the threads and tighten slowly with a calibrated torque wrench to prevent seizure.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Can I get mill certificates for A4 material?\u003c\/strong\u003e\u003cbr\u003e\nA: Yes. FULLERKREG provides mill certificates confirming SUS316 chemical composition including molybdenum content upon request. Please specify this requirement when placing your order.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eQ: Do you offer custom lengths or thread pitches?\u003c\/strong\u003e\u003cbr\u003e\nA: Yes. FULLERKREG can produce non-standard configurations. Please contact us with your technical requirements.\u003c\/p\u003e","products":[],"url":"https:\/\/www.fullerkr.com\/collections\/din-916-iso-4029-socket-set-screw-cup-point-a4-stainless.oembed","provider":"Fullerkreg Fasteners","version":"1.0","type":"link"}