FAQ – Wuxi Hengzhihui Metal Materials Co., Ltd.

General Questions

Q1: What products does Wuxi Hengzhihui manufacture?

A: We specialize in two main product categories:

1. Seamless Steel Tubes – Cold drawn carbon steel tubes in sizes from 6mm to 204mm OD, wall thickness 1-18mm, to ASTM, ASME, EN, DIN, GB standards

2. Die Casting Parts – Aluminum and zinc alloy die casting parts up to 800T, part weight up to 10kg

Our steel tubes are used in heat exchangers, condensers, high pressure boilers, low temperature pipelines, hydraulic systems, and petrochemical applications.

Q2: What size range do Wuxi Hengzhihui supply for steel tubes?

A: We supply seamless steel tubes from 6mm to 204mm outer diameter. Our standard stock sizes range from 19mm to 89mm, with wall thicknesses from 1mm to 18mm. Custom sizes are available upon request.

Q3: What standards do Wuxi Hengzhihui supply?

A: We supply to multiple international standards:

• ASME / ASTM: SA179, A179, SA192, A192, SA178, A178, SA333, A333, SA334, A334, SA335

• API: API 5L, API 5CT, API 5DP

• EN: EN 10216-1, EN 10216-2, EN 10305

• DIN: DIN 17175, DIN 2391

• GB: GB/T 5310, GB/T 8163, GB/T 3087, GB/T 8162, GB/T 9948, GB/T 18984

Product & Technical Questions

Q4: What is the difference between seamless and welded pipe?

A: Seamless pipe is formed from a solid billet with no weld seam. It offers higher pressure integrity, uniform mechanical properties, and is preferred for high-pressure, high-temperature, and critical applications. Welded (ERW) pipe has a longitudinal weld seam, is more cost-effective, and is suitable for general applications. Seamless pipe typically costs 20-40% more than welded pipe.

Q5: What is cold drawing?

A: Cold drawing is a precision manufacturing process where hot rolled tubes are pulled through a die at room temperature to reduce diameter and wall thickness. This process:

• Achieves tight dimensional tolerances (±0.05mm)

• Improves surface finish

• Increases mechanical strength (cold working effect)

• Produces consistent wall thickness

Q6: What is the difference between ASTM A179 and ASTM A192?

A: ASTM A179 is for heat exchangers and condensers – thin wall (0.5-3mm), low carbon, ≤72 HRB hardness, OD up to 3″. ASTM A192 is for high pressure boilers – heavier wall (1-15mm), larger OD (up to 7″), slightly higher hardness (≤77 HRB).

Q7: What is the difference between ASTM A333 and ASTM A334?

A: ASTM A333 covers pipes (larger diameters, 1/4″ to 24″) for low temperature pipelines. ASTM A334 covers tubes (smaller diameters, 1/8″ to 5″) for low temperature heat exchangers. Both are impact tested at -45°C for Grade 6.

Ordering & Payment Questions

Q8: What is minimum order quantity (MOQ) of Wuxi Hengzhihui?

A: Our MOQ depends on the product:

• Stock sizes: 1 ton per size

• Custom sizes: 5 tons per size

• Die casting parts: 500 pieces

• Samples: No MOQ – sample orders welcome

Q9: What payment methods do Wuxi Hengzhihui accept?

A: We primarily accept T/T (Telegraphic Transfer / Wire Transfer). Our standard terms are: 30% deposit to start production, 70% balance paid in full before shipment. This structure is industry standard and balances the interests of both parties.

Currency options: USD, RMB

Q10: What is your typical lead time?

A: Lead times vary by product:

• Stock steel tubes: 7-15 days

• Custom steel tubes: 20-30 days

• Die casting parts: 20-30 days (after sample approval)

• New molds: 4-6 weeks

Quality & Certification Questions

Q11: Do Wuxi Hengzhihui provide mill test certificates?

A: Yes. Every shipment includes an EN 10204 Type 3.1 Mill Test Certificate with full traceability from melt to finished product. EN 10204 Type 3.2 is available upon request with third-party inspection.

Q12: What testing do Wuxi Hengzhihui perform?

A: All products undergo:

• 100% hydrostatic testing – pressure integrity verification

• 100% eddy current testing (ECT) – surface defect detection

• Tensile testing – strength verification

• Hardness testing – grade control

• Dimensional inspection – size verification

Q13: Do Wuxi Hengzhihui support third-party inspection?

A: Yes. We work with SGS, BV, TUV, DNV, or any customer-specified agency.

Shipping & Logistics Questions

Q14: Do Wuxi Hengzhihui ship internationally?

A: Yes. We export to over 30 countries worldwide including USA, Canada, Europe, Middle East, Southeast Asia, South America, and Africa. We ship by sea, air, rail, and express courier.

Q15: What are your packaging methods?

A: Steel tubes are packaged in hexagonal bundles with steel strapping, anti-rust oil, and plastic end caps. Die casting parts are individually bagged and packed in cartons with pallets. Molds are shipped in wooden crates.

Q16: Can I visit your factory?

A: Yes. We welcome customers to visit our factory in Wuxi, Jiangsu Province. Please contact us in advance to arrange a factory tour.

Still Have Questions?

If you didn't find the answer you were looking for, please don't hesitate to contact us. We are happy to help!

📧 Email: yjhtrade@gmail.com
📞 WhatsApp: +86 15106174543
🌐 Website: www.hzhmetals.com / www.wuxihengzhihui.com

Contact Person: Alice Yuan

We typically respond within 24 hours.