Carbon Steel Material Guide: Grades, Standards, Properties & Selection

This comprehensive guide is created for international steel buyers, engineers, EPC contractors, and project managers who need reliable, decision-oriented information about carbon steel materials.

In one place, this guide helps you:

• What Is Carbon Steel
• Understanding Carbon Steel Standards
• Carbon Steel Classification
• Chemical & Mechanical Properties
• Common Carbon Steel Plate Sizes & Grades
• Factors Affecting Selection & Cost
• Carbon Steel vs Other Steels
• Carbon Steel Weight & Calculation

What Is Carbon Steel?

Carbon steel is an iron-based alloy in which carbon is the primary alloying element, with limited additions of manganese, silicon, phosphorus, and sulfur. Unlike alloy steels or stainless steels, carbon steel does not rely on large amounts of chromium, nickel, or molybdenum to achieve performance.

Because of this simple composition, carbon steel offers:

• Predictable mechanical behavior
• Excellent weldability for structural grades
• Wide availability across global standards
• Cost efficiency for large-scale projects

As a result, carbon steel is widely used across structural, industrial, and general fabrication applications.

Understanding Carbon Steel Standards and Grade Systems

In international procurement, carbon steel grades are designated under different standard systems such as ASTM, EN, GB, and JIS, each with its own naming logic, chemical composition limits, and mechanical property requirements.

Commonly used carbon steel standard systems include:

• ASTM (United States) – application-oriented standards such as A36 (structural steel), A572 (high-strength structural steel), and A516 (pressure vessel quality steel).
• EN (Europe) – strength-based grades such as S235, S275, and S355, where the number indicates minimum yield strength in MPa.
• GB (China) – grades like Q235 and Q355, closely aligned with EN yield-strength concepts but defined by domestic specifications.
• JIS (Japan) – grades such as SS400, commonly used in Asian markets and export fabrication.

In cross-border projects, buyers often need to align carbon steel grades from different standards, as technically comparable grades may follow different designation rules and testing methods.

To better understand how carbon steel fits into the broader structural steel supply landscape, you may find our
Structural Steel Sourcing Guide: Types, Grades, and Global Standards helpful when planning multi-standard or cross-border procurement.

Carbon Steel Classification by Carbon Content

Carbon steel is typically classified based on carbon content, which directly affects strength, ductility, and weldability.

1. Low Carbon Steel

Widely used for structural plates and fabricated components. Known for good weldability, forming performance, and balanced strength.

2. Medium Carbon Steel

Provides higher strength and hardness, commonly used for mechanical parts and shafts rather than primary structures.

3. High Carbon Steel

Offers high hardness and wear resistance, mainly used in tools and specialized components.

In construction and infrastructure projects, low carbon structural steel plates account for the majority of demand.

Chemical Composition and Mechanical Properties

Carbon steel performance is defined by a combination of chemical composition limits and mechanical property requirements specified in each standard.

Key chemical elements include carbon, manganese, silicon, phosphorus, and sulfur. Proper control of these elements affects weldability, toughness, and consistency.

Mechanical properties typically evaluated include:

• Yield strength
• Tensile strength
• Elongation
• Impact toughness

These values form the technical basis for selecting grades suitable for load-bearing, forming, or pressure-related applications. Among low carbon structural steels, ASTM A36 steel plate is one of the most widely specified grades for buildings, bridges, general fabrication, and industrial structures. It represents a typical balance of strength, weldability, and availability, making it a common reference point when evaluating carbon steel materials.

For a detailed breakdown of its chemical composition limits, mechanical properties, density values, and commonly accepted international equivalent grades, you can refer to our dedicated guide on
ASTM A36 Steel Plate – Chemical Composition, Properties, Equivalent Grades & Density Guide

Common Carbon Steel Plate Sizes, Thickness & Grades

After defining material type and standard, the next step is choosing practical plate specifications.

Carbon steel plate grades are selected based on structural design requirements, applicable standards, thickness range, and required mechanical properties such as yield strength and toughness.

Carbon steel plates are supplied in:

• Wide thickness ranges for structural and industrial use
• Standard mill widths and cut-to-length formats
• Grades aligned with international design codes

Not all carbon steel grades are available in every thickness range, as rolling capability, delivery condition, and mill production limits directly affect which grades can be supplied in plate form.

To streamline this process, we provide a dedicated reference covering internationally used carbon steel plate thickness ranges, common sizes, and grades.

View common carbon steel plate sizes, thickness ranges & grade reference tables

Key Factors Affecting Carbon Steel Selection and Cost

Beyond mechanical performance, several practical factors influence both material selection and final project cost:

• Carbon content and micro-alloying elements
  Affect base steel pricing and availability.
• Rolling and delivery condition
  Hot rolled, normalized, or controlled rolled conditions impact performance and cost.
• Dimensional tolerances and surface quality
  Standard commercial tolerances vs tighter project requirements.
• Order format and logistics
  Plate vs coil supply, order volume, and shipping efficiency.

Considering these factors early helps reduce specification changes, delays, and cost overruns.

Carbon Steel vs Other Steel Types

Carbon steel is often evaluated alongside other materials during design and procurement.

Key comparisons include:

• Carbon Steel vs. Alloy Steel: What’s the Difference and Which One to Use?
• Weathering Steel vs. Regular Steel: Which is Better for Outdoor Structures?

Each comparison focuses on strength, corrosion behavior, lifecycle cost, and application suitability.

Carbon Steel Weight and Calculation Tools

Accurate weight estimation is essential for pricing, logistics, and structural planning. Carbon steel plate weight depends on thickness, width, length, and density assumptions. For fast and accurate estimation, you can:

• Use the Carbon Steel Plate Weight Calculator
• Use the Carbon Steel Coil Weight Calculator

Ready for the Next Step

Carbon steel remains the backbone material for global construction and engineering due to its balance of strength, availability, and cost efficiency.

If this guide has helped you narrow down suitable grades, standards, or thickness ranges, the next step is technical confirmation and quotation.

• Contacting a carbon steel materials specialist for grade verification and alternatives
• Returning to the carbon steel product center to review available specifications

Sustainability and Service Life of Carbon Steel

Carbon steel is one of the most recyclable construction materials, with a recycling rate exceeding most alternatives. With proper surface protection and maintenance, its service life in structural applications can be significantly extended.

These characteristics align carbon steel with modern sustainability and lifecycle considerations in infrastructure and industrial projects.

FAQ About Carbon Steel

• Q1. What is carbon steel material?
  Carbon steel material is an iron-based alloy in which carbon is the primary alloying element. It contains limited amounts of manganese, silicon, phosphorus, and sulfur, and does not rely on large additions of chromium or nickel like stainless steel. Because of its simple composition, carbon steel offers predictable mechanical behavior, good weldability for structural grades, and cost efficiency for large-scale projects.
• Q2. What are the main types of carbon steel?
  Carbon steel is commonly classified into low carbon steel, medium carbon steel, and high carbon steel based on carbon content. Low carbon steel is widely used for structural plates and fabrication due to good weldability and balanced strength. Medium carbon steel provides higher strength and hardness for mechanical parts. High carbon steel offers high wear resistance and is mainly used for tools and specialized components.
• Q3. What are carbon steel grades?
  Carbon steel grades are standardized material designations that define chemical composition limits, mechanical property requirements, and applicable delivery conditions. Grades are specified under different standard systems such as ASTM, EN, GB, and JIS, and are typically differentiated by strength level, carbon content range, and intended application.
• Q4. What are carbon steel standards?
  Carbon steel standards are technical specifications that define chemical composition, mechanical properties, testing methods, and delivery conditions. Commonly used standards include ASTM (United States), EN (Europe), GB (China), and JIS (Japan). These standards ensure material consistency and regulatory compliance in international projects.
• Q5. What is the chemical composition of carbon steel?
  The typical chemical composition of carbon steel includes carbon as the primary alloying element, with controlled amounts of manganese, silicon, phosphorus, and sulfur. The exact limits depend on the specific grade and standard. Proper control of these elements affects weldability, strength, toughness, and consistency in structural and industrial applications.
• Q6. What are the mechanical properties of carbon steel?
  Key mechanical properties of carbon steel include yield strength, tensile strength, elongation, and impact toughness. These properties vary by grade, standard, and delivery condition. Structural carbon steel grades are designed to provide a balance of strength, ductility, and weldability for load-bearing applications.
• Q7. How much carbon is in carbon steel?
  Carbon steel typically contains up to about 2.0% carbon by weight. Low carbon structural steels usually contain less than 0.25% carbon, medium carbon steels contain approximately 0.25–0.60%, and high carbon steels contain more than 0.60%. The exact carbon content range is defined by each grade and standard.