Product Overview This product is a high-strength spring lock washer (also known as a spring washer, split lock washer, or elastic washer) manufactured to GB/T 93-2025 (Fasteners — Single Coil Spring Lock Washers — Normal Type) . It is available in black oxide (发黑), zinc-plated (镀锌), and hot-dip galvanized (热镀锌) surface finishes, with boxed packaging for retail and industrial distribution. The spring washer is a critical anti-loosening component in bolted connections. Its core value lies in "active anti-loosening": when the bolt is tightened, the washer is compressed to generate elastic deformation, forming a continuous axial preload that offsets torque attenuation caused by vibration and prevents the bolt from loosening due to frequent vibration. This makes it particularly suitable for high-frequency vibration scenarios such as motors, pumps, and automotive chassis. GB/T 93-2025 is the current Chinese national standard for normal-type single coil spring lock washers, applicable to sizes from 1.6 mm to 48 mm. The standard specifically notes that when these spring washers are used with Grade 10.9 and 12.9 bolts and screws, attention must be paid to the "spring expansion" (涨圈) phenomenon — a critical consideration for high-strength bolted connections. Product Type & Design Feature Description Product Type Single Coil Spring Lock Washer / Split Lock Washer Standard GB/T 93-2025 (current) / GB/T 93-1987 (superseded) International Equivalent DIN 127 B (ordinary type) Structure Single coil, square ends, with wavy or spiral edge configuration Function Anti-loosening, preload maintenance, vibration resistance Size Range M1.6 – M48 (standard); M3–M30 most common Packaging Boxed (盒装) for retail / bulk carton for industrial The spring washer is an elastic annular thin sheet, usually made by stamping metal plates and subjecting them to heat treatment. It has a through-hole in the center that matches the bolt shank diameter, with its edge in a wavy or spiral shape. Unlike flat washers that passively increase contact area, spring washers actively maintain fastening pressure through their own elasticity. Material & Hardness Parameter Details Standard Material 65Mn spring steel Alternative Materials 70 spring steel / Stainless steel (201, 304, 316) Hardness Range HRC 42–48 (approximately 430–480 HV) Elasticity Requirement Rebound rate ≥ 80% after compression Surface Treatment Black Oxide / Zinc Plated / Hot-Dip Galvanized / Dacromet 65Mn spring steel is the standard material for GB/T 93 spring washers, offering an optimal balance of elasticity, hardness, and fatigue resistance. The material is hardened to HRC 42–48 (approximately 430–480 HV) to provide the spring properties required for effective anti-loosening performance. Stainless steel options (SS201, SS304, SS316) are available for corrosion-resistant applications. SS316 (A4) is recommended for marine, coastal, and chemical environments where chloride resistance is required. Standards & Specifications Parameter Details Product Standard GB/T 93-2025 (replaces GB/T 93-1987) International Equivalent DIN 127 B (ordinary type) Size Range 1.6 mm – 48 mm (nominal bolt diameter) Material 65Mn spring steel (standard) Hardness HRC 42–48 Surface Finish Black Oxide / Zinc Plated / HDG / Dacromet Packaging Boxed (盒装) / Bulk carton GB/T 93 vs. DIN 127: GB93 has a single precision grade, with a structure closer to DIN 127 Class B. However, the free height of GB93 washers is slightly higher — for example, the free height of an M8 washer is approximately 3.5 mm for GB93 versus 3 mm for DIN 127 — providing stronger elasticity and making it more suitable for heavy machinery with severe vibration. Key Dimensions (Reference — GB/T 93) Nominal Size Inner Diameter (d) min. Outer Diameter (D) Thickness (s) Free Height (H) M3 3.1 mm 6.2 mm 0.8 mm 1.6 mm M4 4.1 mm 8.2 mm 1.1 mm 2.2 mm M5 5.1 mm 10.0 mm 1.3 mm 2.6 mm M6 6.1 mm 12.0 mm 1.6 mm 3.2 mm M8 8.1 mm 16.0 mm 2.1 mm 4.2 mm M10 10.2 mm 20.0 mm 2.6 mm 5.2 mm M12 12.2 mm 24.0 mm 3.1 mm 6.2 mm M16 16.2 mm 30.0 mm 4.1 mm 8.2 mm M20 20.2 mm 36.0 mm 5.0 mm 10.0 mm M24 24.5 mm 44.0 mm 6.0 mm 12.0 mm Dimensions are in accordance with GB/T 93-2025. Free height values are typical reference values and may vary by manufacturer. Surface Finish Options Finish Appearance Salt Spray Resistance Recommended Environment Black Oxide (发黑) Deep black 72–96 hours Indoor, machinery, tooling Zinc Plated (镀锌) Blue-white / Clear / Yellow 72–144 hours Indoor, general industrial Hot-Dip Galvanized (HDG) Silver-gray, matte 500–800+ hours Outdoor, coastal, marine Dacromet Silver-gray 600–1,500+ hours Coastal, offshore, high-corrosion Black oxide provides a sleek black appearance with 72–96 hours of salt spray resistance, suitable for indoor and protected environments. Zinc plating offers sacrificial (cathodic) protection and is suitable for general industrial applications. Hot-dip galvanizing (HDG) provides the thickest coating (45–85 μm) and is recommended for outdoor, coastal, and heavy structural applications. Hilti's HDG spring washers (DIN 127) are specified for moderately corrosive outdoor and indoor environments, with the HDG finish providing improved corrosion resistance. Important note for high-strength bolts: The standard spring washer is made of 65Mn spring steel with hardness HRC 42–48. When used with Grade 10.9 and 12.9 bolts, the "spring expansion" (涨圈) phenomenon may occur — the washer may expand and lose its locking effect under high preload. For critical high-strength applications, DIN 6796 disc spring washers are recommended as a superior alternative for Grade 8.8–12.9 bolted connections. Applications Spring lock washers are widely used across industries: Machinery & Equipment — Motors, pumps, compressors, gearboxes, bearings Automotive — Chassis components, engine mounts, transmission housings, brake systems Construction — Steel structures, formwork, scaffolding, HVAC supports Electrical & Electronics — Control panels, terminal blocks, equipment enclosures Oil & Gas — Pipeline supports, valve assemblies, pump mounting Power Generation — Turbine components, generator connections, switchgear General Assembly — Any bolted joint subject to vibration or dynamic loading Regional insight: In the Middle East, HDG spring washers are widely specified for outdoor and coastal applications in oil & gas, petrochemical, and construction projects. Black oxide spring washers are commonly used in indoor machinery and equipment assembly where corrosion exposure is limited. For high-strength bolted connections (Grade 10.9/12.9) , the 涨圈 phenomenon must be considered, and DIN 6796 disc spring washers may be specified as an alternative. Quality Assurance All products are manufactured under strict quality control procedures in accordance with GB/T 93-2025 and relevant international standards. Quality control steps performed on each production batch: Chemical composition verification of 65Mn spring steel Hardness testing to confirm HRC 42–48 Elasticity/rebound rate testing (≥ 80% required) Dimensional inspection for inner diameter, outer diameter, thickness, and free height Surface finish verification — coating thickness and salt spray testing Visual inspection for cracks, burrs, and surface defects Material test certificates (EN 10204 3.1), dimensional inspection reports, hardness test reports, and third-party inspection reports (SGS, BV, CTI) can be provided upon request. Packaging & Customization Boxed Packaging (盒装): Retail-ready boxes for distribution Bulk Packaging: Cartons / wooden cases / steel pallets for industrial orders OEM/ODM: Available — custom sizes, materials (SS304, SS316), surface finishes (black oxide, zinc plated, HDG, Dacromet), and packaging can be produced according to drawings or samples MOQ: Negotiable Ordering Information To place an order or request a quotation, please specify: Product type — Single coil spring lock washer (GB/T 93) Standard — GB/T 93-2025 / DIN 127 B Material — 65Mn spring steel (standard) / SS304 / SS316 Size — e.g., M6, M8, M10, M12, M16 Surface finish — Black Oxide / Zinc Plated / HDG / Dacromet Packaging — Boxed (specify quantity per box) / Bulk carton Quantity — With any tolerance for over/under shipment Certification — EN 10204 3.1 MTC / Hardness test report / SASO (for Saudi Arabia) / EAC (for Kazakhstan) Special requirements — Marking, packaging, custom sizes FAQ: High-Strength Spring Lock Washers for Central Asia & the Middle East 1. What standards should I specify for spring washers in GCC projects? Answer: The primary standards for spring lock washers in the Gulf region are: Standard Scope GCC Usage GB/T 93-2025 Single coil spring lock washers — normal type Chinese-origin equipment and projects DIN 127 Spring lock washers — German standard European-spec projects; widely recognized in GCC ASME B18.21.1 Lock washers (inch series) US-spec projects JIS B 1251 Spring lock washers — Japanese Japanese-origin equipment GB/T 93-2025 is the current Chinese national standard, applicable to sizes from 1.6 mm to 48 mm. DIN 127 B is the equivalent German standard for ordinary-type spring washers, and GB93 is structurally closer to DIN 127 Class B. Practical guidance: For GCC projects, specify GB/T 93 for Chinese-origin equipment or DIN 127 B for European-spec projects. For US-spec projects, ASME B18.21.1 applies. Always confirm the project specification before ordering. 2. What are the equivalent GOST standards for Central Asia? Answer: Central Asian countries operate under the GOST standards system, with the following key standard for spring washers: GOST Standard Description International Equivalent GOST 6402-70 Spring washers — Specifications DIN 127 / GB/T 93 GOST 6402-70 is the primary Russian/CIS standard for spring washers, covering sizes from M3 to M48 with materials including 65G spring steel (65Mn equivalent) . Practical implication: For Kazakhstan and Central Asian projects, GB/T 93 / DIN 127 spring washers in 65Mn spring steel will generally satisfy GOST 6402-70 requirements, provided EAC certification and Russian/Kazakh language documentation are included. 3. What certification is required for Kazakhstan and Central Asia? Answer: Central Asian countries operate under the Eurasian Economic Union (EAEU) certification system. EAC Certification: Certification Type Applicability Fastener Coverage EAC DoC (Declaration of Conformity) Medium/low-risk products Fasteners for industrial machinery under TR CU 010/2011 EAC CoC (Certificate of Conformity) High-risk products Lifting equipment, pressure equipment GOST-K (National) Products not covered by EAEU regulations Construction materials, building fasteners TR CU 010/2011 (Machinery Safety) is the applicable technical regulation for spring washers used in industrial machinery, mechanical equipment assembly, and structural connections. The typical form of assessment is a Declaration of Conformity (DoC) . GOST-K Certification (Kazakhstan): For construction materials and building fasteners, GOST-K certification is required under Kazakhstan's Decree No. 435 (Building Safety Technical Regulations). Key requirements include: Requirement Details −40°C Low-Temperature Impact Testing Mandatory for construction materials Russian/Kazakh Language Documentation Product labels and certificates must be in Russian and/or Kazakh GOST-K Mark + Dynamic QR Code Mandatory from 2025 Kazakh Agent Required Non-EAEU manufacturers must appoint a Kazakh representative Practical implication: For spring washers exported to Kazakhstan and Central Asia, EAC DoC under TR CU 010/2011 is typically required. For construction applications, GOST-K certification with −40°C impact testing may also be required. 4. What certification is required for Saudi Arabia? Answer: Saudi Arabia requires SABER certification for regulated products, including construction materials and fasteners. SABER Certification — 2025 Policy Update: As of January 1, 2025, all goods exported to Saudi Arabia must obtain PCoC (Product Conformity Certificate) and SCoC (Shipment Conformity Certificate) through the SABER system. The previous "Undertaking Letter" customs clearance method has been completely abolished. Certificate Validity Scope PCoC (Product Conformity Certificate) 1 year Per product model/type SCoC (Shipment Conformity Certificate) Per shipment Per batch; must be obtained before vessel arrival Applicable technical regulations: Spring washers fall under Technical Regulation for Building Materials Part 1: Metallic and Alloy Components for Buildings and Construction. Fasteners are specifically included in the regulated product list. Key requirements: Local importer required: Chinese manufacturers cannot apply directly; the Saudi importer must initiate the application on the SABER platform. Arabic or bilingual product labels are mandatory. HS Code updates: SABER platform HS codes have been continuously updated since 2025. Practical implication: For spring washers exported to Saudi Arabia, PCoC and SCoC through SABER are mandatory as of 2025. Ensure all technical documentation and product labels are in Arabic or bilingual. 5. Why does the "涨圈" (spring expansion) phenomenon matter for high-strength bolts? Answer: This is a critical safety consideration for high-strength bolted connections, and it is explicitly noted in GB/T 93-2025. The mechanism: When standard spring washers (65Mn, HRC 42–48) are used with Grade 10.9 and 12.9 bolts, the high preload generated during tightening can cause the washer to expand (涨圈) — the washer flattens and expands outward, losing its spring effect and anti-loosening capability. This is because the washer's elastic limit is exceeded under the high clamping force of high-strength bolts. The GB/T 93-2025 standard note: The standard specifically states: "When the spring washers specified in this document are used with Grade 10.9 and 12.9 bolts and screws, attention should be paid to the spring expansion phenomenon". Recommended alternative: For Grade 8.8–12.9 high-strength bolted connections, DIN 6796 disc spring washers are recommended as a superior alternative to standard spring washers. DIN 6796 washers are specifically designed for high-strength bolts and screws such as grade 8.8, 10.9, and 12.9, providing high axial load capacity, elastic recovery, and long service life. GCC procurement guidance: For Grade 8.8 bolts and below: Standard GB/T 93 spring washers are suitable. For Grade 10.9 and 12.9 bolts: Consider DIN 6796 disc spring washers or verify with the project engineer that the standard spring washer is acceptable. For critical structural connections: Specify DIN 6796 to ensure reliable preload maintenance. 6. What are the common applications for spring washers in the Middle East? Answer: Application Typical Size Surface Finish Why Spring Washer Machinery & Equipment M6–M16 Black Oxide / Zinc Vibration resistance, motor and pump mounting Automotive M6–M12 Zinc / Black Oxide Chassis components, engine mounts Construction M10–M20 HDG Steel structures, formwork, HVAC Oil & Gas M12–M24 HDG / Dacromet Pipeline supports, valve assemblies Electrical & Electronics M3–M8 Zinc / Black Oxide Control panels, terminal blocks General Industrial M4–M20 All finishes Any bolted joint subject to vibration Regional insight: In the Middle East, HDG spring washers are widely specified for outdoor and coastal applications in oil & gas, petrochemical, and construction projects. Black oxide spring washers are commonly used in indoor machinery and equipment assembly where corrosion exposure is limited. 7. What documentation is required for GCC import? Answer: Document Requirement Level Notes EN 10204 3.1 Material Test Certificate Standard requirement Chemical composition, hardness Hardness Test Report Standard requirement Confirming HRC 42–48 Elasticity Test Report Recommended Confirming rebound rate ≥ 80% Coating Certificate Standard for HDG/Dacromet orders Confirming coating thickness SASO / SABER Certificate Required for Saudi Arabia PCoC + SCoC through SABER ESMA Conformity Required for UAE Certificate of conformity for customs EAC DoC / GOST-K Required for Kazakhstan Per TR CU 010/2011 and Decree No. 435 Packing List Standard With batch identification matching certificates Regional practice: UAE-based suppliers issue EN 10204 3.1 test certificates with every batch. For Saudi Arabia, SASO/SABER certification is mandatory for construction materials. 8. What are the most common sizes ordered in the GCC? Answer: Size Typical Application Frequency in GCC M3–M6 Electrical panels, instrumentation, small machinery High M8–M12 General machinery, pump/valve assembly, HVAC Very High M16–M20 Heavy machinery, structural connections, oil & gas High M24–M30 Large infrastructure, bridge connections, power generation Moderate Regional availability: Spring washers in M3–M30 are routinely available from UAE and Saudi stockists in black oxide, zinc-plated, and HDG finishes. Standard sizes are stocked for immediate delivery. 9. What is the lead time and availability in the GCC? Answer: Scenario Typical Lead Time Standard sizes (M3–M20) in UAE/Saudi stock Same day to 3 days Non-stock sizes or finishes (HDG, M24+) 1–2 weeks Custom or project quantities 4–6 weeks Import from China/India 4–6 weeks (plus customs clearance) Regional availability: Spring washers in M3–M20 are routinely stocked in Dubai and Saudi Arabia for immediate delivery. HDG and Dacromet-coated variants are increasingly stocked for coastal and offshore applications. 10. What is the price range for spring washers in the Middle East? Answer: Grade / Size Approximate Unit Price (USD) Black Oxide M6 $0.01 – $0.03 Black Oxide M8 $0.02 – $0.05 Zinc Plated M8 $0.02 – $0.06 Zinc Plated M12 $0.04 – $0.10 HDG M10 $0.05 – $0.12 HDG M16 $0.10 – $0.25 HDG M20 $0.15 – $0.35 Factors affecting price: Material — 65Mn spring steel is standard; stainless steel is 3–5× higher Surface finish — HDG adds 30–50% over zinc plating Size — Larger sizes (M20+) are disproportionately more expensive Quantity — Bulk orders (100,000+ pieces) receive 15–25% discounts Certification — EN 10204 3.1 and SASO compliance add 5–10% Packaging — Boxed packaging adds 10–20% over bulk 11. What are the common causes of spring washer failure in Middle East site conditions? Answer: Failure Mode Root Cause Prevention Spring expansion (涨圈) Used with Grade 10.9/12.9 bolts exceeding elastic limit Use DIN 6796 disc spring washers for high-strength bolts Loss of elasticity Over-compression during installation Torque to specification; do not exceed washer elastic limit Corrosion pitting Inadequate surface finish for environment Specify HDG for outdoor/coastal; Dacromet for offshore Cracking Material defect or hydrogen embrittlement Verify hardness and material certificates; use Dacromet for high-strength Galvanic corrosion Contact with dissimilar metals in chloride environment Isolate with flat washers; specify SS316 for marine Critical field warning: If a spring washer fractures or loses its spring effect days after installation, inspect for hydrogen embrittlement (brittle fracture) or spring expansion (flattened washer). Verify the material certificates and surface treatment records with the supplier. 12. What information should be included in an RFQ for spring washers in the GCC? Answer: A complete RFQ should specify: Standard: GB/T 93-2025 / DIN 127 B / ASME B18.21.1 Product type: Single coil spring lock washer (normal type) Material: 65Mn spring steel (standard) / SS304 / SS316 Size: e.g., M6, M8, M10, M12, M16 Surface finish: Black Oxide / Zinc Plated / HDG / Dacromet Hardness: HRC 42–48 (standard) Packaging: Boxed (specify quantity per box) / Bulk carton Quantity: With any tolerance for over/under shipment Certification: EN 10204 3.1 MTC / Hardness test report / SASO (for Saudi Arabia) / EAC DoC (for Kazakhstan) Special requirements: Marking, packaging, custom sizes Common RFQ mistake: Specifying only "M8 spring washer" without stating the standard, material, hardness, and surface finish. This creates ambiguity that can lead to unsuitable substitutions — particularly when standard spring washers are supplied for a Grade 10.9/12.9 bolted connection where spring expansion may occur, or when zinc-plated washers are supplied for a coastal application where HDG is required.