Chinese Material Grades and International Equivalents
A practical guide to GB material designations and their ASTM, EN, DIN, and JIS counterparts
How Chinese Material Designations Work
Chinese material grades follow a structured naming system defined in GB/T 221. Unlike Western designations that use descriptive names or alloy compositions, Chinese grades use a letter prefix indicating the material's property class, followed by numbers.
Common Structural Carbon Steels
The most widely used Chinese structural steel is Q235. The system is straightforward:
- Q stands for qufu dian (yield point)
- 235 is the minimum yield strength in MPa
Other common grades include Q195, Q215, Q275, Q345, Q390, Q420, and Q460 — higher numbers mean higher strength.
| Chinese GB | EN (Europe) | ASTM (USA) | JIS (Japan) | Use |
|---|---|---|---|---|
| Q235B | S235JR | A283 Grade C | SS400 | General structural: buildings, bridges, general fabrication |
| Q345B | S355JR | A572 Grade 50 | SM490A | Higher strength structural: heavy machinery, shipbuilding |
| Q460C | S460NL | A572 Grade 65 | SM570 | High strength: crane booms, pressure vessels |
Note: These are approximate equivalents. Always verify with the relevant standard for critical applications.
Quality Carbon Structural Steels (45#, 20#, etc.)
These steels are designated by the average carbon content in hundredths of a percent:
- 20# — 0.20% average carbon. Low-carbon steel for carburizing parts.
- 45# — 0.45% average carbon. The most common medium-carbon steel for shafts, gears, and machine components.
| Chinese GB | EN (Europe) | AISI/SAE (USA) | JIS (Japan) | Use |
|---|---|---|---|---|
| 20# | C22E | 1020 | S20C | Carburizing: gears, pins, bushings |
| 45# | C45E | 1045 | S45C | General engineering: shafts, axles, bolts |
| 40Cr | 41Cr4 | 5140 | SCr440 | Alloy steel: gears, crankshafts, high-strength bolts |
Stainless Steels
Chinese stainless steel grades use a different system, similar to the international AISI three-digit system:
| Chinese GB | AISI | EN (Europe) | Type | Common Use |
|---|---|---|---|---|
| 06Cr19Ni10 | 304 | X5CrNi18-10 | Austenitic | Food equipment, kitchenware, architectural |
| 022Cr19Ni10 | 304L | X2CrNi19-11 | Austenitic (low carbon) | Welded structures, chemical equipment |
| 06Cr17Ni12Mo2 | 316 | X5CrNiMo17-12-2 | Austenitic (Mo) | Marine, chemical, pharmaceutical |
| 10Cr17 | 430 | X6Cr17 | Ferritic | Appliance trim, automotive exhaust |
Cast Iron Grades
Cast iron designations in China follow a straightforward prefix system:
- HT — huitie (gray cast iron). Followed by minimum tensile strength in MPa. Example: HT250 = gray iron, 250 MPa tensile.
- QT — qiuti (ductile/nodular iron). Followed by tensile strength and elongation. Example: QT400-18 = ductile iron, 400 MPa tensile, 18% elongation.
| Chinese GB | EN (Europe) | ASTM (USA) | Common Use |
|---|---|---|---|
| HT200 | EN-GJL-200 | Class 30 | Machine bases, engine blocks |
| HT250 | EN-GJL-250 | Class 35 | Cylinder heads, machine tool beds |
| QT400-18 | EN-GJS-400-18 | 60-40-18 | Automotive suspension, valve bodies |
How to Find the Right Standard for a Material
- Identify the material grade — Determine the Chinese designation (e.g., Q235, 45#, 304)
- Find the governing standard — Each material grade is defined in a specific GB or GB/T standard. For example, Q235 is defined in GB/T 700 (Carbon Structural Steels). Search for this standard on our platform to see the full chemical composition and mechanical property requirements.
- Cross-reference the equivalent — Use the tables above or our Material Grade Lookup tool to find international equivalents in ASTM, EN, DIN, or JIS.
- Check both standards — Equivalents are approximate. Always verify critical parameters (tensile strength, chemical composition, impact requirements) against both the Chinese and international standards.
Try it now: Search our Material Cross-Reference by entering a Chinese grade like Q235, 45#, or 304 to find international equivalents and the governing GB standards.