| Carbon Content Classification | Quality & Application Classification | Hot-Rolled State | Cold-Rolled State |
| Low-Carbon Steel (C ≤ 0.25%) Characteristics: Excellent plasticity, toughness, and weldability | Ordinary Structural/Commercial Grade (Primarily guarantees mechanical properties, lowest cost) | • ASTM A36
• SS400 (JIS)
• S235JR (EN)
• Q235A/B (GB) | • DC01 (EN) •SPCC (GB/JIS) • CR2/CR3 (ASTM) |
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| Quality Structural/Drawing Grade (Strict control of both composition & properties, good formability) | • A572 Gr.50 (ASTM)
• SM490A (JIS)
• S355JR (EN)
• Q355B/C/D (GB) | • DC03, DC04 (EN)
• SPCD (GB/JIS)
• DQ, DDSK (ASTM) |
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| Advanced Forming/Deep Drawing Grade (IF Steel) (Ultra-deep drawing, non-aging) | Rarely used directly as sheet. Typically serves as the hot-rolled coil feedstock for cold-rolled deep-drawing steels. | • DC05, DC06 (EN)
• SPCE, SPCF (JIS/GB)
• EDDQ/S-EDDQ (Generic) |
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| High-Strength Low-Alloy (HSLA) / Advanced High-Strength Steel (AHSS) (High strength, balances formability & weldability) | • A572 Gr.60/65 (ASTM)
• S420MC/S460MC (EN)
• Q390/Q420/Q460 (GB) | • HC340/590DP (GB, Dual Phase steel)
• DP600, TRIP800 (Generic)
• HCT600X (EN) |
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| Medium-Carbon Steel (0.25% < C ≤ 0.60%) Characteristics: Good strength-toughness combination achievable via heat treatment | Machinery Manufacturing Steel (Used for core load-bearing parts after quenching & tempering) | • 1045 (SAE)
• S45C (JIS, hot-rolled material)
• 45# (GB, hot-rolled plate/flat bar) | • 1045 (SAE, cold-rolled strip)
• S45C (JIS, cold-rolled precision material)
• 45# (GB, cold-rolled precision stock) |
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| High-Carbon Steel (C > 0.60%) Characteristics: High hardness, high wear resistance, high brittleness | Tool & Special Purpose Steel (Belongs to special steel category) | • 65Mn (GB, spring steel flat bar)
• 1095 (SAE)
• T8, T10 (GB, Tool Steel) | Very rare. May exist as cold-rolled strip or thin sheet for making high-precision spring strips, blades, or special wear-resistant shims. |
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