← Glossary

1.0503

C45

The 1.0503 (C45) is a mild steel: easily weldable, inexpensive, and the workhorse of structural steel. The "S" means the guaranteed [[glossary:streckgrenze|yield strength]] in MPa — S355 holds at least 355 MPa. Typical analysis: 0.45 % C, 0.65 % Mn, 0.25 % Si. For higher [[glossary:verschleissschutz|wear protection]], three hard-facing options are available: S Fe 1 (martensitic, approx. 300–400 HB, machinable), S Fe 2 (wear-resistant and tough, approx. 50–55 HRC, conditionally machinable) and S Fe 15 ([[glossary:karbid|carbide]]-rich, approx. 55–65+ HRC, not machinable).

AI Transparency (EU AI Act): Created on the basis of our own many years of practical experience in welding technology, with the help of AI, and reviewed editorially.

© 2026 Welder-World. All content is for training and continuing education and does not replace a certified welding procedure specification.