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What Are the Four Steel Types?

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With exceptional strength and mechanical properties, steel delivers a versatile material option for a wide range of construction and building projects. While there are different classifications or grades of steel, all steel grades are comprised of iron and carbon. The varying composition of each type of steel differentiates the four basic steel categories.

Identifying the Four Types of Steel

The four main types of steel include carbon steel, stainless steel, alloy steel, and tool steel. Learn how the different kinds of steel are categorized and how each type can work for your project requirements.

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Carbon Steel

As general-purpose steel, carbon steel is available with varying elements of carbon. Low carbon (mild) steel includes 0.30% or less carbon
  • Medium or mid-carbon steel includes 0.30%-0.60% carbon
  • High carbon steel includes more than 0.60%-1.5% carbon
From construction to manufacturing, carbon steel is widely used throughout a wide range of industries.

Stainless Steel

Often used for hygienic applications, stainless steel comprises 10%-20% of chromium, nickel, or molybdenum. Ideal for medical equipment, food processing equipment, appliances, and structural purposes, stainless steel offers you strength and corrosion resistance in addition to low maintenance upkeep.

Alloy Steel

With a mix of aluminum, copper, nickel, and other elements such as titanium or manganese, alloy steel is cost-efficient and includes at least 5% alloying elements. Often used for pipes, alloy steel is easily machinable and provides good corrosion resistance.

Tool Steel

Used for toolmaking and drilling equipment, tool steel is an abrasion-resistant material option. Tool steel is characterized by its extreme hardness and ability to hold a cutting edge at high temperatures. Tool steel often contains varying levels of cobalt, tungsten, molybdenum, or vanadium.  

What Are the Most Useful Steel Grades and Identification Methods?

Steel grade classification includes ASTM and AISI/SAE standards for identification.

ASTM Grading

The ASTM grading system utilizes letters and a sequential number as designators for the metal category. For example, ASTM A36 reflects low-carbon structural steel. It has a yield strength of 36,000 psi. The “A” reflects that it is a ferrous metal, and the “36” reflects the mechanical properties.
ASTM standards reflect classifications based on material, mechanical, chemical, and metallurgical properties. Steel products that abide by ASTM standards reflect the quality and performance-based standards that meet your material needs.

AISI/SAE Grading

The AISI/SAE grading system uses a four-digit system to identify different steels. The first digit reflects carbon steels. The second digit demonstrates the concentration of elements. The last two numbers reflect the carbon concentration in each steel. For example, AISI/SAE 1018 reflects low-carbon steel.

  • 1XXX – Carbon steels Carbon Steel Rods on Construction Site
  • 2XXX – Nickel steels
  • 3XXX – Nickel-chromium steels
  • 4XXX – Molybdenum steels
  • 5XXX – Chromium steels
  • 6XXX – Chromium-vanadium steels
  • 7XXX – Tungsten-chromium steels
  • 9XXX – Silicon-manganese steels

Steel Surface Appearance

While surface finishes vary among steel types, there are surface finishing options for each steel type.

Carbon Steel

  • Hot rolled steel can be oiled and pickled
  • HR steel results in a rough surface finish
  • Cold rolled steel provides a smooth surface finish
    • Surface finish is smoother than HR steel due to the carbon content

Carbon Steel Applications

  • Building and construction materials
  • Pipelines
  • Automotive parts
  • Forgings
  • Gears
  • Machine components

Stainless Steel

  • Aesthetically pleasing shiny surface finish due to levels of chromium
    • A higher chromium content will result in a highly reflective surface
  • Often used for decorative or architectural purposes
  • Can be found with brushed finishes

Stainless Steel Applications

  • Medical equipment
  • Food and beverage components
  • Piping
  • Cutting tools
  • Architecture
  • Aircraft materials

Dipped Steel

  • Galvanization
    • Often hot-dipped with a thicker layer of zinc
  • Zinc plated
  • Raw dipped
  • Spangle

Dipped Steel Applications

  • Power generation and transmission
  • Infrastructure development
  • Mining
  • Telecommunications
  • Oil and gas

Galvanized Steel

  • Surface finish of galvanized steel is a matte finish
  • Galvanized steel offers a thick layer of zinc, delivering exceptional corrosion resistance

Galvanized Steel Applications

  • Automotive components
  • Telecommunications
  • Construction
  • Wind and solar manufacturing
  • Agriculture industries

What is the Difference Between MS and SS?

Mild or low-carbon steel is the most common form of steel in existence. Mild steel is less expensive than other steel forms, and due to its carbon content of .05-.025%, it is highly malleable and ductile. Mild steel is also machinable and weldable.
On the other hand, stainless steel contains 10-20% chromium, along with silicon, nickel, manganese, and carbon, providing high corrosion resistance levels for various applications. Stainless steel is available in several alloy options, including 304 and 316.

The IMS Difference

What separates IMS from other metals companies? With an abundance of metal options and customer service that is second to none, IMS has you covered with the following advantages:
  • Next day delivery of processed material via our trucks
  • Same day pick up in Will-Call
  • No minimum purchase
  • Support of Just-in-Time manufacturing processes
  • Salespeople that act as an extension of your purchasing department (we will get any metal products you need)
  • Material management (stocking and delivery on a scheduled basis)
  • Credit lines with good terms
  • Knowledgeable staff that knows metal
  • Six stores that are open six days a week (check each location for specific times)

Delivering Premium Steel Throughout Southern CA, Arizona & Nevada

Industrial Metal Supply is your trusted supplier of premium in-stock steel products, including stainless steel barsheet, and plate, as well as tubingpipe, and structural shapesGet in touch with our sales team for world-class metal products and services today.

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