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Russian Our Factory | DingLong Hardware — Precision Fastener Manufacturer in Wujiang, China
We deliver high-performance fastening solutions engineered for precision screws
Three Core Manufacturing Advantages
Every DingLong shipment is backed by in-house engineering, fully traceable production, and internationally audited quality systems.
In-House R&D & Engineering
Our 12-person engineering team handles custom thread profiles, non-standard geometries, and material selection. Pre-production calculations follow DIN 931/933/939/976 with full dimensional simulation before tooling is cut. New product feasibility assessed within 24 hours.
Vertically Integrated Production
Cold & hot forging (M6–M64), CNC thread rolling, quench-and-temper heat treatment (grades 8.8/10.9/12.9), surface coating (Dacromet, HDG, Geomet, zinc-nickel), and final inspection — all on-site. Zero subcontracting of strength-critical operations ensures full heat-number traceability.
Third-Party Verified Quality
Every batch ships with EN 10204 Type 3.1 MTR, dimensional inspection records (IT6/IT7 tolerance class), and hardness/tensile test data. SGS and TÜV factory audits annually. Bureau Veritas, Intertek pre-shipment inspections standard for European and automotive OEM buyers.
Precision Fastener Manufacturer — Wujiang, China
Wujiang DingLong Metal Hardware Products Co., Ltd. operates a 12,000 m² vertically integrated fastener facility in Suzhou, Jiangsu — producing stud bolts, hex flange bolts, hexagonal screws, threaded rods, T-type screws, nuts, and washers for high-speed rail, 5G infrastructure, automotive OEM, and civil construction markets. EN 10204 Type 3.1 · IATF 16949 · SGS / TÜV audited.
R&D and Engineering Design Process
Before a single piece of raw material enters production, DingLong’s engineering team validates every new fastener through a structured four-stage process — eliminating costly rework and ensuring first-time conformance.
| Stage | Activities | Output |
|---|---|---|
| 1 · Requirements Analysis | Review customer drawings, application load data, environmental exposure (temperature, corrosion, vibration), and applicable standards (DIN, ISO, ASTM, JIS, GB) | Technical spec sheet, standard reference list, material shortlist |
| 2 · Structural & Thread Design | Thread form selection (metric coarse/fine, UN, ACME, trapezoidal), shank geometry, grip length, heat treatment hardness target | CAD drawings, thread tolerance tables, heat treatment spec |
| 3 · Engineering Review & Optimization | FEA stress simulation for critical joints, tooling design review, hydrogen embrittlement risk management for grade 12.9 electroplated parts | Approved engineering drawings, risk mitigation report |
| 4 · Prototype & First-Article Inspection | Sample run (50–100 pcs), CMM dimensional check, proof load test, 240-hour salt spray (ASTM B117), full FAIR | FAIR report, golden sample, production authorization |
Key Manufacturing Equipment
DingLong’s production floor is equipped with purpose-built fastener manufacturing machinery, calibrated and maintained to OEM specifications.
Production Capacity & Key Metrics
| Plant Floor Area | 12,000 m² · Wujiang, Suzhou, Jiangsu Province, China |
| Monthly Output | 800 metric tons (bolts, stud bolts, threaded rod, nuts combined) |
| Size Range | M6 to M64 — cold forged M6–M36 · hot forged M30–M64 |
| Strength Grades | 4.6 / 4.8 / 5.8 / 8.8 / 10.9 / 12.9 (ISO 898-1) · A2-70 / A4-80 (ISO 3506) · B7/2H (ASTM A193/A194) |
| Thread Forms | Metric coarse/fine (DIN 13) · UNC/UNF (ASME B1.1) · Tr trapezoidal · ACME · BSW/BSF · custom profiles |
| On-Time Delivery Rate | ≥ 98.2% (rolling 12-month average, verified by shipping records) |
| Sample Lead Time | 5–7 business days (catalogue) · 10–15 business days (custom/OEM) |
| Mass Production Lead Time | 15–30 days (size, coating process, and order volume dependent) |
| Standard MOQ | 500 kg per line item (waived for trial qualification orders) |
| Annual Factory Audit | SGS factory audit · TÜV SÜD IATF 16949 surveillance audit |
Three-Stage Quality Control System
Aligned with ISO 9001:2015 and IATF 16949:2016. Every shipment is supported by a complete quality dossier traceable to the original raw material heat number.
IQC — Incoming
- All raw material quarantined on arrival
- OES spectrometer chemical composition vs mill certificate
- Tensile & hardness spot checks
- Dimensional sampling per AQL 2.5
- Non-conforming lots returned regardless of schedule pressure
- No production release without IQC sign-off
IPQC — In-Process
- Forging die dimensional check every 500 parts
- Thread GO/NO-GO gauge per ISO 1502 every 200 parts
- Post-heat-treatment Rockwell HRC spot check every batch
- Coating thickness measurement every hour
- SPC charts with ±2σ control limits for corrective action
OQC — Outgoing
- AQL 1.5 dimensional sampling per ISO 2859-1
- Minimum 240-hour salt spray for coated parts
- Proof load testing per ISO 898-1
- Visual: surface defects, thread damage, marking legibility
- Docs: CoC · EN 10204 Type 3.1 MTR · coating report · REACH/RoHS declaration
Certifications & Compliance Documentation
DingLong Hardware maintains the following active certifications. Certificate copies available for supplier qualification packages — request via info@productionscrews.com.
| Certification / Standard | Scope | Issuing Body |
|---|---|---|
| ISO 9001:2015 | Quality management — design, manufacture, and supply of precision fasteners (bolts, stud bolts, threaded rods, nuts, washers) | SGS / Bureau Veritas |
| IATF 16949:2016 | Automotive quality management — OEM-grade fasteners for chassis, suspension, and powertrain applications | TÜV SÜD |
| CE Marking (EN 14399 / EN 15048) | Structural bolting assemblies for preloaded and non-preloaded connections — EU construction market | EC Declaration of Conformity |
| RoHS 2.0 — 2011/65/EU | Restriction of hazardous substances in fastener surface coatings, plating baths, and packaging materials | SGS |
| REACH SVHC Compliance | No SVHC substances above 0.1% w/w (current ECHA candidate list, updated annually) | Third-party accredited lab |
| EN 10204 Type 3.1 MTR | Material test reports with chemical composition and mechanical properties, per production heat/batch | DingLong QC Manager |
| SGS Factory Audit | Annual manufacturing process audit and social compliance assessment | SGS |
| Conflict Minerals (OECD DD) | Supply chain due diligence for tin, tantalum, tungsten, and gold in raw material supply chain | DingLong Purchasing Dept. |
Sample Development & Supplier Qualification Workflow
Procurement managers can initiate a structured qualification process before committing to production orders.
Send PDF technical drawings, DIN/ISO/ASTM standard numbers, or a physical sample for reverse engineering. Engineering team responds with DFM assessment and quotation within 24 hours on business days.
Standard catalogue items: 5–7 business days. Non-standard thread forms, special materials (SUS316L, Inconel 718), or extended-cure coatings (HDG, Geomet 500): 10–15 business days. Rush service 3–5 days at additional cost.
All samples ship with complete FAIR: dimensionally ballooned drawing, CMM measurement report, thread gauge records, hardness test, Ra surface finish, coating thickness report, salt spray result. AIAG PPAP format for automotive customers.
DingLong’s technical team available for consultation on installation torque specifications, lubrication requirements, and on-site torque audit support via video call for overseas customers.
Upon sample approval, production scheduling begins immediately. No additional tooling lead time for standard sizes (M6–M36). Custom tooling: 5–10 additional days, charged separately and amortized over agreed production volumes.
Frequently Asked Questions
Our manufacturing facility is in Wujiang, Suzhou, Jiangsu Province, China — approximately 80 km from Shanghai Pudong International Airport. Wujiang is a key precision metal manufacturing hub in the Yangtze River Delta industrial corridor, supporting efficient FCL/LCL export to Hamburg, Rotterdam, Port Klang, Laem Chabang, and Tanjung Priok.
Standard production covers M6 to M64 in bolt, stud bolt, and threaded rod form. Cold forging handles M6–M36; hot forging extends coverage to M64. Threaded rod is produced in continuous lengths up to 3,000 mm. Sizes beyond M64 or lengths exceeding 3,000 mm are available via our CNC machining center.
Yes. Our engineering team regularly manages multi-standard orders — for example, DIN 931 hex bolts alongside ASTM A193 B7 stud bolts and JIS B 1180 bolts. We confirm the applicable standard on every order acknowledgement and production traveler to prevent mix-ups during picking and packing.
IATF 16949:2016 covers design and manufacture of precision bolts, stud bolts, and threaded rods for automotive chassis, suspension, and powertrain applications. We provide certified certificate copies for supplier qualification files. Products outside the certified scope are manufactured under ISO 9001:2015 with equivalent documentation.
Yes — we actively encourage and facilitate inspections by SGS, Bureau Veritas, TÜV SÜD, Intertek, or customer-nominated inspectors. Our QC team provides all inspection records in advance and maintains a dedicated inspection area with calibrated instruments. Third-party inspection is built into default QC planning for export orders above 5 metric tons.
Our HE prevention protocol: (1) Alkaline or mechanical pre-treatment replaces acid pickling for all 10.9/12.9 parts wherever possible; (2) Where electroplating is customer-specified, post-plate baking at 190–210°C for minimum 4 hours per ASTM F1941 is performed within 4 hours of plating; (3) Proof load testing per ISO 898-1 on a batch sample basis. For safety-critical applications, we recommend Dacromet, Geomet, or HDG — all acid-free processes with zero HE risk.
Standard MOQ is 500 kg per line item — the minimum economical run for cold forging and coating lines. For new customer qualification or NPI, trial orders without MOQ are accepted (typically 50–200 kg). Trial order pricing reflects small-batch setup costs; pricing normalizes at full MOQ.
Yes. OEM and private label services include: custom head marking (manufacturer mark, grade designation, customer logo — cold stamped or laser-engraved), proprietary packaging design, and confidential product specifications protected under NDA. All OEM agreements include a signed confidentiality agreement and IP protection clause.
Standard documentation per shipment: commercial invoice, packing list, bill of lading, certificate of origin (Form E for ASEAN; EUR.1 for EU), EN 10204 Type 3.1 MTR, Certificate of Conformance, REACH SVHC declaration, RoHS compliance declaration. For EU structural applications: CE Declaration per EN 14399 or EN 15048. Optional: fumigation certificate, SGS pre-shipment inspection certificate.
Factory visits and third-party audits are welcome. Contact our export sales team at least 10 business days in advance. For overseas buyers, we offer live virtual factory walkthroughs via Microsoft Teams or WeChat Video — covering the production floor, QC laboratory, heat treatment line, and coating area. Email info@productionscrews.com to schedule.