C-20 carbon steel

Introduction

We manufacture forging ingots, billets, and blooms in carbon steel specifically for C-20, designed for low to medium strength engineering applications where good formability, machinability, and weldability are essential.

C-20 is a low carbon, unalloyed steel that offers excellent ductility, toughness, and ease of fabrication. Due to its lower carbon content, it exhibits limited hardenability but provides very good machinability and superior weldability compared to medium and higher carbon grades.

This grade is ideal for applications that do not require high hardness or wear resistance but demand consistent performance, cost-effectiveness, and easy processing. C-20 is widely used in general engineering, structural, and fabricated components.

Chemical composition

Element Content (%) Function / effect
Carbon (c) 0.17 – 0.23 Provides basic strength while maintaining high ductility
Manganese (mn) 0.30 – 0.60 Improves toughness and machinability
Sulphur (s) 0.050 max Enhances machinability when controlled
Phosphorus (p) 0.050 max Controlled to maintain toughness
Silicon (si) 0.05 – 0.30 Acts as deoxidizer and improves strength
Chromium (cr) Nil Not intentionally added
Nickel (ni) Nil Not present
Molybdenum (mo) Nil Not present
Other elements — No significant alloying additions

Mechanical properties (typical – normalized condition)

  • Tensile strength: 370 – 470 MPa
  • Yield strength: 220 – 280 MPa
  • Elongation: 25 – 30 %
  • Hardness: 120 – 170 HB

Heat treatment

  • Annealing: improves ductility and machinability
  • Normalizing: refines grain structure and enhances uniform mechanical properties
  • Case hardening: suitable for surface hardening applications
  • Quenching & tempering: not commonly used due to low carbon content

Key features and benefits

  • Excellent formability and weldability
  • Good machinability
  • High ductility and toughness
  • Cost-effective for mass production
  • Ideal for case hardened components

Typical applications

  • Shafts and pins
  • Bolts, nuts, and fasteners
  • Structural and fabricated parts
  • Automotive brackets and frames
  • General engineering components

Equivalent Steel Grades

  • C20 (En Standard)
  • Din 1.0402
  • Aisi 1020 (Closest American Equivalent)

Why Choose C20 For Your Application?

C20 Is An Excellent Choice For Components Requiring A Combination Of A Hard Wear-Resistant Surface And A Tough Core. Its Suitability For Carburizing Makes It Ideal For Parts Subjected To Friction And Moderate Loads, While Maintaining Good Machinability And Cost Efficiency.

Comparison table for similar grades

Grade Carbon (%) Strength level Hardenability Typical use
C-15 0.12 – 0.18 Low Very low Sheets, fabrication
C-20 0.17 – 0.23 Low–medium Low General engineering
C-30 0.27 – 0.34 Medium Moderate Shafts, axles
C-35 0.32 – 0.39 Medium Moderate Automotive parts
C-45 0.40 – 0.50 High Good High load components

Summary

C-20 carbon steel is a reliable low carbon engineering grade offering excellent formability, machinability, and weldability. It is an ideal choice for low to medium strength applications where cost-effectiveness and ease of fabrication are priorities.