35# round steel (GB/T 699) is a medium-low carbon structural steel with a composition designed for versatility: 0.32–0.40% carbon (C), 0.17–0.37% silicon (Si), 0.50–0.80% manganese (Mn), ≤0.035% phosphorus (P), ≤0.035% sulfur (S), and trace elements (Cr ≤0.25%, Ni ≤0.30%). This blend offers a sweet spot between formability and strength, making it suitable for parts requiring moderate load-bearing capacity and ease of machining.
The 0.32–0.40% carbon content provides tensile strength of 530–670 MPa, while the manganese (0.50–0.80%) enhances hardenability without excessive brittleness. Its international equivalents include AISI 1035 (USA), DIN C35 (Germany), and JIS S35C (Japan), all of which share similar chemistry and are used in applications like bolts, shafts, and gears. 35# is commonly listed on Made-in-China.com as "35# Carbon Steel Round Bar for General Machinery," valued for its cost-effectiveness in mid-range structural roles.