| 1 | AISI 1045 Medium-high carbon steel | 0.43–0.50 | Mn: about 0.60–0.90 | Balanced strength, toughness, and machinability; can be induction hardened. | Shafts, axles, pins, gears, structural components, and general engineering parts. | Limited weldability compared with low-carbon steel; moderate cold formability. |
| 2 | AISI 1060 High carbon steel | 0.55–0.65 | Mn: about 0.60–0.90 | Higher hardness and wear resistance than 1045 while retaining useful toughness. | Cutting tools, knives, springs, wear plates, and components requiring a hard edge. | Poor weldability without careful preheating and post-weld control; limited cold forming. |
| 3 | AISI 1070 High carbon steel | 0.65–0.75 | Mn: about 0.60–0.90 | Good hardenability for a plain-carbon grade, high strength after heat treatment, and good wear resistance. | Flat springs, blades, agricultural tools, washers, and wear-resistant parts. | Very limited weldability; generally formed before final hardening. |
| 4 | AISI 1080 High carbon spring steel | 0.75–0.88 | Mn: about 0.60–0.90 | High strength, hardness, and elastic response after quenching and tempering. | Springs, clips, saw blades, scraper blades, and resilient components. | Not readily weldable; cold forming is normally limited to the annealed or spheroidized condition. |
| 5 | AISI 1095 Extra-high carbon steel | 0.90–1.03 | Mn: about 0.30–0.50 | Very high attainable hardness and edge retention; lower impact toughness than lower-carbon grades. | Knife blades, saw blades, scrapers, wear strips, and high-strength springs. | Extremely poor weldability; requires careful heat treatment to reduce cracking and distortion. |
| 6 | 65Mn Manganese spring steel | 0.62–0.70 | Mn: 0.90–1.20; Si: commonly 0.17–0.37 | Higher strength and hardenability than plain-carbon spring steels; good fatigue performance when properly treated. | Spring washers, leaf springs, retaining rings, agricultural blades, and clamps. | Poor weldability; moderate formability in annealed condition and low formability after hardening. |
| 7 | 60Si2Mn Silicon-manganese spring steel | 0.56–0.64 | Si: 1.50–2.00; Mn: 0.60–0.90 | Excellent elastic limit, fatigue resistance, and hardenability for spring applications. | Automotive leaf springs, coil springs, suspension parts, and high-load spring components. | Very poor weldability; hot forming and controlled heat treatment are preferred. |
| 8 | SK5 High carbon tool steel | 0.80–0.90 | Mn: about 0.10–0.50; Si: about 0.10–0.35 | High hardness and wear resistance with strong edge-holding capability after hardening. | Utility knives, shears, saw blades, cutting tools, and precision strip components. | Poor weldability; good machinability and forming are mainly available before hardening. |
| 9 | C80 EN high carbon steel | 0.75–0.85 | Mn: about 0.60–0.90; Si: about 0.10–0.40 | Good combination of hardness, strength, and wear resistance; commonly supplied as precision strip or coil. | Springs, saws, blades, clips, scrapers, and stamped wear-resistant parts. | Poor weldability; suitable for cold working when supplied annealed or in a controlled condition. |
| 10 | C100S EN extra-high carbon steel | 0.95–1.05 | Mn: about 0.30–0.60; Si: about 0.10–0.40 | Very high hardness and wear resistance after heat treatment; excellent for thin, sharp-edged components. | Industrial blades, saw components, scrapers, measuring tools, and high-wear strip parts. | Extremely poor weldability; requires controlled forming, hardening, and tempering practices. |