| 1 | C60 / SAE 1060 | 0.55–0.65 | Plain carbon steel; manganese typically about 0.60–0.90% | 0.30–6.00 | Austenitize, oil or water quench, then temper; spheroidize annealing may be used before cold forming. | Approximately 35–50 HRC, depending on section size and tempering temperature | Good balance of strength, wear resistance, toughness, and formability compared with higher-carbon grades. | Clips, washers, agricultural components, wear strips, and moderately loaded springs |
| 2 | C67 / SAE 1065–1070 | 0.60–0.70 | Plain carbon spring steel with moderate manganese content | 0.20–4.00 | Oil quenching followed by tempering; austempering is possible for selected strip sizes. | Approximately 42–52 HRC | Higher elastic strength and fatigue resistance than C60, with useful springback control. | Flat springs, clips, retaining rings, blades, and general-purpose spring components |
| 3 | C75 / SAE 1075 | 0.70–0.80 | Plain carbon steel; typically supplied with manganese around 0.50–0.80% | 0.15–3.00 | Quench and temper for spring properties; spheroidized condition improves machinability and cold forming. | Approximately 45–55 HRC | High tensile strength, good wear resistance, and strong elastic recovery after tempering. | Saw blades, spring washers, agricultural blades, knives, and stamped spring parts |
| 4 | C80 / SAE 1080 | 0.75–0.85 | Plain carbon steel with relatively high manganese for hardenability | 0.15–3.00 | Oil quench and temper; controlled heating is important to reduce distortion and decarburization. | Approximately 48–58 HRC | High hardness and wear resistance with good spring performance; toughness decreases if over-hardened. | Industrial blades, saw components, high-load springs, scrapers, and wear-resistant parts |
| 5 | C85 / SAE 1084 | 0.80–0.90 | Plain carbon steel; high carbon level supports high as-quenched hardness | 0.15–2.50 | Quench and temper; spheroidize annealing is commonly used before demanding cold-work operations. | Approximately 50–60 HRC | Very good edge retention and wear resistance, but limited weldability and lower impact toughness. | Cutting blades, spring strips, wear plates, scrapers, and precision stamped components |
| 6 | C90 / SAE 1090 | 0.85–0.95 | Plain high-carbon steel; manganese improves hardenability to a limited extent | 0.15–2.00 | Oil quench and temper, often with a lower tempering temperature when high hardness is required. | Approximately 52–61 HRC | Excellent wear resistance and high strength; greater risk of cracking and distortion during quenching. | Knife components, industrial cutters, high-strength springs, and wear-resistant strips |
| 7 | C100 / SAE 1095 | 0.90–1.03 | Very high-carbon plain steel; manganese commonly about 0.30–0.50% | 0.10–2.00 | Carefully controlled austenitizing, oil quench, and tempering; subcritical annealing may be used for forming. | Approximately 55–64 HRC | Very high hardness, strength, and edge retention; relatively low toughness and poor weldability. | High-performance blades, fine springs, wear strips, scrapers, and cutting tools |
| 8 | 65Mn | 0.62–0.70 | Manganese spring steel; manganese is typically about 0.90–1.20% | 0.20–4.00 | Oil quench and temper; controlled cooling and tempering help stabilize spring properties. | Approximately 42–52 HRC | Good strength, elasticity, fatigue resistance, and hardenability for general spring applications. | Automotive leaf springs, clutch components, spring washers, saw blades, and agricultural tools |
| 9 | 60Si2Mn | 0.56–0.64 | Silicon-manganese spring steel; silicon is commonly about 1.50–2.00% | 0.30–4.00 | Oil quench and temper; silicon improves elastic limit and resistance to softening during tempering. | Approximately 42–52 HRC | High elastic limit, strong fatigue performance, and better spring reliability under repeated loading. | Heavy-duty springs, suspension components, torsion bars, and high-stress spring strips |
| 10 | 75Cr1 | 0.70–0.80 | Chromium-alloyed carbon spring steel; chromium generally improves hardenability and wear resistance. | 0.20–3.00 | Oil quench and temper; spheroidized annealing can improve machinability and forming behavior. | Approximately 45–56 HRC | Improved hardenability, wear resistance, and dimensional consistency compared with plain carbon spring steel. | Industrial knives, circular saw components, spring parts, scrapers, and wear-resistant tooling |