Mon - Sat: 8:00 - 18:00 Handan, Hebei

Case Study: High-Strength Bolts & Lock Nuts for a Steel Structure Warehouse in the USA

SteelMaster’s regular Asian supplier had quality consistency issues – previous shipments failed torque tests due to irregular thread tolerance. For this urgent warehouse projec

Case Study: High-Strength Bolts & Lock Nuts for a Steel Structure Warehouse in the USA

Project Details

Customer: SteelMaster Buildings LLC (Texas, USA)
Project: 80,000 sq. ft. prefabricated steel warehouse for a logistics hub in Houston
Challenge: Required Grade 8.8 and Grade 10.9 high-strength hex bolts, lock nuts, and flat washers complying with DIN 933, DIN 934, and ASTM equivalents, with full material test reports (MTC) and batch traceability. Delivery window: 30 days.


The Challenge

SteelMaster’s regular Asian supplier had quality consistency issues – previous shipments failed torque tests due to irregular thread tolerance. For this urgent warehouse project, the customer needed:

  • 85 tons of Grade 8.8 & 10.9 hex bolts (M12–M24, various lengths)

  • 30 tons of Grade 10 lock nuts (DIN 934)

  • 15 tons of flat & spring washers (DIN 125, DIN 127)

  • Surface treatment: Zinc plated (blue-white) for indoor use

  • Additional requirement: All products must pass a third-party pre-shipment inspection (SGS) and be fully traceable to heat numbers.

SteelMaster had previously worked with two other Chinese fastener suppliers but suffered from delayed deliveries and missing certification documents.


Our Solution

Yuanpai Fastener proposed using two dedicated sub-brands:

  • Changgu – our high-strength fastener line (Grade 8.8/10.9/12.9, GB 5783, GB 5782)

  • Tianbao – full range nuts including lock nuts

Within 24 hours, our technical team provided:

  • Product dimension drawings

  • Tensile strength & hardness test reports (in-house lab)

  • Sample of heat number stamping on bolt heads

Because we maintain 70,000 tons of inventory and produce 800 tons daily, we allocated raw material from our dedicated stock for Grade 10.9 alloy steel (40Cr & 35CrMo). We arranged continuous production across three shifts and completed manufacturing in 22 days.

Quality control highlights:

  • 100% thread go/no-go gauge inspection

  • Salt spray test (minimum 72 hours for zinc plating)

  • Magnetic particle inspection for surface cracks on Grade 10.9 bolts

  • Each pallet labeled with batch number, heat number, and spec sheet

Packaging: 25kg kraft paper bags + steel pallets, container-ready for Houston port.

SGS conducted random sampling at our facility – all samples passed with a 99.8% acceptance rate.


The Results

  • Delivery completed: 28 days (2 days ahead of schedule)

  • Cost savings: 22% lower than their previous US-based distributor

  • Certifications provided: EN 10204 Type 3.1 mill test certificates, ISO 9001, batch traceability documents

  • Repeat business: SteelMaster signed a 12-month frame agreement for minimum 500 tons annually

“Yuanpai Fastener restored our confidence in Chinese manufacturing. The quality control was excellent – every batch matched the test certificate. Their Changgu and Tianbao sub-brands delivered exactly what we needed, on time, with full documentation. We have already placed two more orders.”
 Jennifer Walsh, Supply Chain Manager, SteelMaster Buildings LLC


Key Success Factors




RequirementYuanpai Solution
High-strength bolts (Grade 8.8 & 10.9)Changgu sub-brand – GB 5783, DIN 933 standards
Lock nuts & washersTianbao sub-brand + Wild Horse washers
Tight 30-day deadline70,000 tons raw material stock; in-house production
Full traceability & MTCHeat numbers on every bolt; EN 10204 3.1 certificates
Third-party SGS inspection100% pass rate – no re-inspection costs

Industries We Support with High-Strength Fasteners

  • Prefabricated steel buildings

  • Warehouse & logistics centers

  • Industrial equipment assembly

  • Automotive frames

  • Heavy machinery


Let’s Solve Your Fastening Challenge

Whether you need Grade 12.9 bolts, hot-dip galvanized screws, or custom packaging – Yuanpai Fastener has the capacity, sub-brands, and quality systems to deliver.

📧 Email: yuanpaifastener@gmail.com
📞 WhatsApp: +86 18531009807

From source to global – we fasten your world