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    331110 - Iron and Steel Mills and Ferroalloy Manufacturing

    The backbone of modern infrastructure and manufacturing, iron and steel play an essential role in numerous industries worldwide. NAICS code 331110 specifically targets the establishments that operate iron and steel mills and ferroalloy manufacturing facilities, a vital segment of the manufacturing sector. Whether it’s producing structural steel for buildings or advanced ferroalloys used in specialty metals, this NAICS code defines a critical industry powering industrial growth and innovation.

    What is NAICS Code 331110?

    NAICS code 331110 encompasses businesses primarily engaged in the operation of iron and steel mills and ferroalloy manufacturing plants. These establishments utilize processes such as smelting, refining, and alloying to produce a wide variety of iron, steel, and ferroalloys. From raw pig iron to finished steel products, these facilities form the core of steel production in the United States.

    Sector: Manufacturing

    This NAICS code falls under the Manufacturing sector, which covers industries involved in the physical or chemical transformation of materials or substances into new products.

    Typical Business Activities

    Businesses under NAICS 331110 typically engage in activities like:

    • Operating integrated steel mills
    • Producing pig iron from iron ore
    • Manufacturing various forms of steel including stainless, tool, and alloy steels
    • Producing ferroalloys such as ferromanganese and ferrochromium
    • Hot-rolling and cold-rolling steel products
    • Refining iron and steel through electrometallurgical processes

    These operations support industries like construction, automotive, aerospace, machinery manufacturing, and infrastructure development.

    NAICS Code 331110 Size Standards

    To qualify as a small business under this NAICS classification, the size standard is:

    • Maximum of 1,500 employees

    This employee threshold applies when determining eligibility for small business programs and government contracting opportunities.

    Examples of Businesses under NAICS 331110

    • Integrated steel producers: Companies handling the whole process from pig iron to finished steel mill products
    • Iron & steel mills: Facilities producing steel billets, blooms, slabs, and bars
    • Ferroalloy manufacturing plants: Producers of ferrochromium, ferromanganese, ferrosilicon, and related high-percentage nonferrous alloying elements

    Detailed Code Descriptions and Products Manufactured

    Product/Activity Description
    Armor plate, iron and steel mills Production of armor-grade steel plates
    Axles, rolled or forged Steel or iron axles produced by rolled or forged methods
    Steel balls Steel balls manufactured for industrial uses
    Concrete reinforcing bars (rebar) Rebars used in concrete reinforcement produced in steel mills
    Billets, blooms, slabs, steel Intermediate steel products formed into billets, blooms, or slabs
    Blackplate and terneplate Steel coated with tin or lead-based alloys
    Blast furnaces Facilities operating blast furnaces for iron smelting
    Car and locomotive wheels Steel wheels for transportation
    Coke oven products Byproducts of coal coking processes
    Direct reduction of iron ore Producing sponge iron via direct reduction methods
    Electrometallurgical steel and ferroalloy manufacturing Refining using electrical furnace techniques
    Ferroalloys manufacturing (ferrochromium, ferromanganese, etc.) Producing alloys essential for steelmaking
    Forgings Iron and steel forgings for industrial components
    Galvanized products Steel products with zinc coating for corrosion resistance
    Hot-rolling and cold-rolling products Shaping steel through rolling techniques
    Iron ore recovery from slag Recycling iron from by-products of steel production
    Pig iron manufacturing Producing raw iron from iron ore
    Stainless steel production Manufacturing corrosion-resistant steel
    Steel mill products (bar, plate, rod, sheet, structural shapes) Variety of finished steel products for construction and manufacturing
    Tube and pipe manufacturing Production of seamless and welded iron/steel tubes and pipes
    Wire products Steel and iron wire manufacture
    Wrought iron or steel pipe and tubing Manufacturing wrought iron products

    (This list represents common products and activities but is not exhaustive.)

    Frequently Asked Questions (FAQs)

    What does NAICS code 331110 encompass?

    NAICS 331110 includes establishments primarily engaged in operating iron and steel mills and ferroalloy manufacturing facilities, producing iron, steel, and ferroalloys through smelting, refining, and alloying.

    Which sector does this NAICS code belong to?

    It belongs to the Manufacturing sector.

    What is the small business size standard for NAICS 331110?

    The size standard is 1,500 employees.

    Can you give examples of typical businesses under this code?

    Yes, examples include integrated steel producers, iron and steel mills, and ferroalloy manufacturing plants.

    What types of products are made in this industry?

    Products range from steel bars, sheets, plates, and wire products to ferroalloys like ferromanganese and ferrosilicon, as well as specialized products like armor plates and galvanized steel.


    By understanding NAICS code 331110, businesses and government agencies can better classify and engage with a key industry that supports economic infrastructure and manufacturing innovation. Whether you’re a contractor seeking opportunities or a firm planning to register your steel production business, knowing the specifics of this NAICS code is critical to your success.


    Keywords: NAICS 331110, Iron and Steel Mills, Ferroalloy Manufacturing, Steel Production, Manufacturing Sector, Small Business Size Standard, Integrated Steel Producers, Ferroalloys, Steel Mills Products.