How Is Tool Steel Made: Manufacturing Process

Tool steel is a high-grade alloy known for its hardness, abrasion resistance, and heat retention, making it essential for cutting tools, dies, and machinery components. Its manufacturing process includes alloying, melting, casting, forging, heat treatment, and precision finishing.

As a seasoned steel manufacturer, we will offer in-depth insights into the detailed production process of tool steel. If you require any tool steel products, please contact us.

What Is Tool Steel Made of?

Tool steel primarily comprises iron and 0.5% to 1.5% carbon. Key alloying elements like chromium, vanadium, molybdenum, tungsten, manganese, and silicon are added to form carbides, enhancing wear resistance and toughness.

Over half of tool steels are made from scrap metal to reduce costs and promote sustainability. Based on our manufacturing experience, it’s best to use scrap free from contaminants such as oil and paint to ensure the longevity of the tool steel.

If you are searching for raw materials for your project, SteelPro Group can provide tool steels that meet international standards with strict tolerance control.

Tool Steel Manufacturing Process

1. Melting and Refining

Most tool steel is made using the Electric Arc Furnace (EAF) because it is efficient, flexible, and can use a large amount of recycled materials. However, other refining methods like Electroslag Melting (ESR) and Powder Metallurgy (P/M) are used when specific tool steel grades, desired properties, or application needs require them.

• Electric Arc Furnace (EAF)

The Electric Arc Furnace (EAF) is the primary method for melting tool steel. We recommend using the EAF process when utilizing a large amount of recycled materials is important for cost savings and environmental sustainability. It is also ideal for producing large quantities of tool steel with consistent quality.

Process:

In the EAF process, steel scrap is loaded into the furnace and melted using a powerful electrical arc. Alloying elements are added to achieve the desired chemical composition. The molten steel is then refined to remove impurities and ensure homogeneity. After refining, the steel is poured into molds to form ingots, which are subsequently annealed to reduce internal stresses.

• Electroslag Melting (ESR)

Electroslag Melting (ESR) is an advanced refining technique. It is particularly valuable for tool steels that require high purity and excellent mechanical properties. We advise choosing ESR when high purity and excellent surface quality are crucial for the tool steel application.

Process:

The consumable steel electrode is submerged in a molten slag pool within a water-cooled mold. An electric current is passed through the electrode, causing it to melt and drip into the slag. As the molten steel passes through the slag, impurities are removed, and the steel solidifies into a homogeneous ingot with a refined microstructure.

• Powder Metallurgy (PM)

Powder Metallurgy (PM) is an advanced manufacturing process used to produce highly alloyed tool steels with uniform carbide distribution. We suggest utilizing Powder Metallurgy when producing tool steels with complex alloy compositions that are difficult to achieve through traditional melting methods. It is also ideal for manufacturing precise and intricate tool shapes with minimal material waste

Process:

In this process, metal powders are carefully blended with alloying elements and compacted into the desired shape using molds. The compacted powders are then sintered at high temperatures, causing the particles to bond and form a solid piece. This method ensures a fine and even distribution of carbides, enhancing the machinability and hardening response of the tool steel.

2. Casting

• Continuous Casting

Continuous casting involves the steady flow of molten steel into a cooled mold, producing long, uniform strands that can be rapidly solidified and directly rolled into desired shapes. This method offers high efficiency and consistency, making it ideal for mass production.

• Ingot Casting

This entails pouring molten steel into large, stationary molds to form discrete blocks. Although slower and more labor-intensive, ingot casting provides greater control over the cooling rates and can accommodate specialized alloy compositions. This technique is especially appropriate for high-grade tool steels requiring meticulous microstructural refinement.

3. Hot Forging and Rolling

Hot forging and rolling are critical steps in shaping tool steel and enhancing its mechanical properties. During hot forging, heated ingots are pressed using high-pressure dies to form billets, bars, or other preliminary shapes. Rolling then further refines these shapes by passing the steel through multiple rolling mills, achieving precise dimensions and uniform thickness.

We achieve consistent high quality and strict tolerances through advanced computer-controlled machinery and real-time monitoring. Our rigorous quality checks guarantee that every tool steel batch meets the highest performance standards.

4. Hot and Cold Drawing

Hot drawing involves pulling tool steel through dies at elevated temperatures, typically up to 540 °C (1000 °F). This process enhances ductility, allowing significant cross-section reductions without breakage. Multiple passes may be necessary to obtain the desired form and measurements. 

Cold drawing is carried out at temperatures close to room temperature to achieve accurate dimensions and excellent surface quality. Given the high strength and restricted ductility of tool steels, cold drawing is generally restricted to a single, light pass to avoid fracture. 

Different Tool Steel Types and Different Process

Tool steels are primarily categorized into six distinct types based on their alloying elements and specific properties tailored for various applications.

• Water-Hardening (W-Series)

Ingot casting is the preferred method for W-Series tool steels. Because of its simpler composition, it does not necessitate advanced casting techniques like ESR or PM.

• Cold-Work (O, A, D-Series)

Demand minimal segregation and uniform carbide distribution, often achieved through ESR or VAR (Vacuum Arc Remelting) to eliminate impurities and enhance homogeneity.

• Shock-Resistant (S-Series)

Vacuum Arc Remelting (VAR) is often utilized to produce these steels, ensuring minimal inclusions and a refined microstructure. 

• Hot-Work (H-Series)

Benefit from continuous casting methods that facilitate the formation of tough and resilient microstructures suitable for high-temperature applications.

• High-Speed (M, T-Series)

Require precise cooling rates to form hard and wear-resistant martensitic structures. Ingot casting with controlled cooling or continuous casting followed by rapid quenching is preferred.

• Powder Metallurgy (PM-Series)

Powder Metallurgy (P/M) is often the preferred casting method for these specialized grades. Additionally, the Osprey Process can be employed for producing fine-grained, highly uniform tool steels tailored for specific industrial needs.

If you want to know more about different types and grades of tool steel, please click here.

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