Specification errors are one of the most expensive problems in China fastener sourcing. The part may be produced correctly according to the supplier’s understanding, but still be wrong for the buyer’s assembly. That is why the RFQ must remove assumptions before price, production, and packing begin.

For importers and distributors, the goal is simple: define the fastener so clearly that there is no room for interpretation.

Start With the Exact Standard

Never quote only by product name. “Hex bolt,” “socket screw,” or “washer” is not enough.

State the standard, size, grade, finish, and quantity in one line. If the part follows DIN, ISO, ASTM, ASME, SAE, JIS, or a customer drawing, write it clearly. For metric standards, this Руководство по стандартам крепежа DIN и ISO is useful when checking common standard references.

Confirm Material and Strength Separately

Material and strength are not the same thing. Carbon steel can be Grade 4.8, 8.8, 10.9, or other classes. Stainless steel may be 304, 316, A2-70, or A4-80.

For general sourcing, review available крепежные изделия and then define the exact material and grade in the RFQ. Do not rely on a supplier to infer strength from the product name.

Control Surface Finish Details

Finish errors are common because different markets use different wording. “Zinc,” “galvanized,” and “plated” are often used casually, but they do not mean the same thing.

State Finish Requirements Clearly

For coated orders, confirm:

• Finish type and color
• Coating thickness, if required
• Salt spray requirement, if any
• Post-coating thread fit
• Matching nut and washer finish
• Packaging needed to prevent rust

For comparison, buyers can review крепеж с покрытием перед завершением RFQ.

Use Drawings for Non-Standard Parts

Photos are helpful, but they do not replace drawings. For shoulder bolts, special studs, turned parts, U-bolts, bent rods, welded parts, and special washers, send a controlled drawing.

The drawing should include:

1. Критические размеры.
2. Tolerances.
3. Material.
4. Heat treatment.
5. покрытие поверхности.
6. Thread standard.
7. Inspection points.
8. Drawing revision.

For made-to-order items, нестандартные крепления should be quoted only after the drawing and inspection requirements are clear.

Request Pre-Production Confirmation

Before mass production, ask for a confirmation sheet or sample approval. This is especially important for new suppliers, new drawings, mixed standards, or urgent projects.

Minimum Confirmation Items

• Описание продукта
• Standard and size
• Материал и класс
• Готово
• Количество
• Упаковка
• Сертификаты
• Редакция чертежа
• Время выполнения

This step catches many errors before raw material is prepared.

Keep Certificates Tied to Lots

Certificates must match the goods shipped. The lot number on the carton should connect with the material certificate, mechanical test report, coating report, or dimensional inspection report.

For стандартные крепления, this is usually straightforward. For mixed or custom orders, traceability needs tighter control.

Final RFQ Rule

A good China fastener order is built on written details, not assumptions. Define the standard, size, material, grade, finish, drawing, inspection, packing, and documents before comparing price.

Покупатели могут свяжитесь с XZ Fastener with drawings, size lists, finish requirements, quantities, packing methods, and certificate needs to reduce specification errors before production.