Revolutionary Tooling Solutions: The Magic of Tool Steel

Tool steel is a special type of steel that is designed to withstand the extreme forces and temperatures involved in shaping, cutting, extruding, and forming metal. The unique properties of tool steels make them an indispensable material for toolmakers, allowing them to create precision tools, molds, dies, and machine parts that would be impossible with other materials. From the drills that pull oil and gas from miles underground, to the molds that shape delicate glassworks—tool steels are the unsung heroes behind many of the manufactured items we rely on every day.

In this article, we’ll explore what makes tool steels so exceptional, how they are produced, the different types and their specialized applications, how tooling engineers select the optimal steel, and the future possibilities opened up by advances in tool steel technology. Discover how this versatile metal helps build our world while pushing the boundaries of what’s possible in manufacturing.

An Introduction to Tool Steels

Tool steels refer to a variety of carbon and alloy steels that are specifically formulated to withstand the demands of being made into tools. Their key characteristics include:

  • Hårdhed: Tool steels obtain high hardness and strength through the addition of alloying elements like tungsten, molybdenum, cobalt, and vanadium. This allows them to withstand tremendous cutting forces and retain their shape at high temperatures.
  • Slidstyrke: They resist abrasion and chipping when sharpened or shaped. This allows tooling made from them to have a long service life before needing replacement.
  • Heat resistance: Tool steels retain their hardness and strength even when exposed to high temperatures caused by friction during machining and forming operations.
  • Hårdførhed: While hard for wear resistance, tool steels also have enough toughness and shock resistance to survive the dynamic loads and impacts that tools routinely experience.
  • Dimensional stability: The materials resist warping or shrinking to hold their precise shapes through repeated heating/cooling cycles.

Tool steels achieve these properties through careful control of their chemistry, as well as proper heat treatment. This balance of hardness, wear resistance, and toughness is what gives finished tool steel components the longevity and performance needed to produce consistent, high-quality workpieces.

A Brief History of Tool Steels

While early civilizations used iron and primitive steels to fashion tools, the history of modern tool steels begins in the 18th century as metallurgy and machining capabilities advanced. Some key developments include:

  • 1740s: English clockmaker Benjamin Huntsman pioneers crucible steel, allowing the production of higher quality tool steels.
  • 1868: Robert Forester Mushet invents R. Mushet’s Special Steel, considered the first true tool steel. It revolutionizes tooling capabilities.
  • 1900s: Advancements in metallurgy and heat treating spawn development of high speed steel. The alloy’s hardness and red hardness allow faster machining.
  • 1915: Tungsten carbide is introduced and eventually helps replace high speed steels with a harder material.
  • Mid 1900s: Continuous casting makes it possible to produce large uniform billets to create newer grades and types of tool steel.
  • Today: Tool steels continue advancing, optimizing compositions and processes to create steels with enhanced properties. Modern powder metallurgy techniques can produce tool steels unattainable through conventional practices.

Tool steel has progressed hand-in-hand with manufacturing and machining capabilities. As techniques like metal cutting and die casting demanded better tooling, metallurgists responded with new steel alloys and processing methods to fill the need. Tool steel sits at the leading edge of what’s possible in manufacturing.

How Tool Steels Are Made

Producing tool steels requires precise control over composition and processing:


Tool steel starts with a base of iron and carbon. Various alloying elements are then added to impart desired attributes. Common alloys include:

  • Tungsten: Boosts hardness and toughness for wear resistance. Also improves strength at high temps.
  • Molybdenum: Increases strength and machinability. Enhances elevated temperature properties.
  • Vanadium: Fine-grains the microstructure for hardness and fatigue strength. Improves wear resistance.
  • Cobalt: Adds hot hardness and facilitates heat treating.
  • Chromium: Improves hardenability, wear/corrosion resistance, and toughness.
  • Manganese: Combines with sulfur to remove it during manufacturing. Provides hardenability.

Strict control over the types and amounts of alloys produces tool steels to specification. Different compositions target different tooling applications and requirements.


Tool steels begin by melting iron and other elements in an electric arc furnace or induction furnace. Most grades use an open hearth or electric furnace with varying temperature controls and protective atmospheres.

Fine-tuned melting controls ensure proper alloy dissolution and a uniform composition. Some higher alloy grades require special processes like vacuum induction melting or vacuum arc remelting to avoid contamination.


The molten steel is cast into a rough shape, often a billet. The steel can be cast in:

  • Ingot molds – Produces rectangular or round ingot billets for further processing.
  • Continuous casters – Forms a continuous strand that is cut into set lengths. Faster than ingot casting.
  • Electroslag remelting – Remelts ingot or continuous cast tool steel to remove impurities and improve uniformity.

Smedning further shapes the steel into bar stock, rod, or other forms needed for toolmaking. Steel in billet form may also undergo shaping steps like extrusion or drawing.


Tool steels derive their key properties from proper heat treatment and tempering after initial wrought processing. Heat treatment involves:

  • Hardening – Heated then quenched at a rapid rate to form martensite and desired hardness.
  • Tempering – Reheating to a specific temperature to remove brittleness and refine grain size. This fine-tunes hardness, toughness, and ductility.
  • Udglødning – Extended heating followed by slow cooling to soften the steel for improved machinability.
  • Stress relieving – Heating to relax residual stresses in the material before final machining.

Tool steel properties directly correlate to following strict thermal processing instructions. Each grade has optimized hardening and tempering procedures.

Categories of Tool Steels

There are thousands of tool steel grades offering different mixes of properties. They can be grouped into seven major categories:

1. Cold work steels

Best suited for punches, dies, and forming tools that shape metal at room temperature. Excellent wear resistance and hardenability. Grades like A2, A6, D2, and D3 (oil hardening steels) are common for blanking, shear blades, tool holders, and press brakes.

2. Shock resisting steels

Have high toughness and compressive strength for impact loads. Used for chisels, claw bars, percussive tools. S1, S5, and S7 grades (chrome-moly shock steels) are typical choices.

3. Hot work steels

Retain hardness and resist thermal fatigue at high temperatures up to 1000°F (540°C). Used for hot forming, extrusion, and die casting dies. Popular alloys include H11, H12, H13, H19, and H21 (chrome-moly hot work steels).

4. High speed steels

Exhibit hardness and wear resistance even when reaching high temperatures from friction during machining. Allow faster cutting speeds than carbon tool steels. Molybdenum-tungsten M and T series grades are commonly used for cutting tools like drills and saw blades.

5. Mold steels

Feature excellent hardenability for larger cross sections. Polishing and texturing capabilities aid mold details and release. P20 and P30 grades are commonly used. Stainless grades like 420, 440C and PH also make good mold tooling.

6. Water hardening steels

Hardened by quenching in water or brine instead of oil. Used for cutting tools where reaching optimal hardness is more important than toughness. Grades like W1 and W2 contain tungsten and chromium carbides for wear resistance.

7. High carbon, high chromium

Achieve maximum hardness when air cooled instead of quenched. Used for punches, woodworking tools, razor blades. Grades like 52100 and 154CM (bearing steels) exhibit high hardness and compressive strength.

This overview shows the diversity of tool steel grades. Each is formulated with its end use in mind, whether shaping cold metal in a progressive die, or cutting alloys at blinding speeds in a CNC lathe.

Tool Steel Selection Criteria

Choosing the optimal tool steel depends on:

Service Conditions

What temperatures, stresses, and wear will the tooling encounter? Is high red hardness required? Will impact loads be present? This helps narrow suitable grades.

Part Accuracy

How much precision and surface finish is needed on the workpiece? Tighter tolerances and finer finishes require dimensionally stable tooling.

Production Volume

Lower volume production can utilize slower but tougher tooling. High volumes demand maximum tool life and uptime before replacement is needed.

Comparative Costs

The steel is only one component. Consider overall costs of machining, heat treating, processing, maintenance, and tool life during production.


Selecting readily available bar stock can avoid long lead times. Custom processed grades may require melting and forging specially ordered billets.


Sticking with known tool steels lowers the learning curve. But new grades may outperform a shop’s standards. Testing new alloys in lower risk applications builds experience.

Careful balancing of those factors results in the ideal match between tool steel and application.

Innovating with Tool Steels

Advancing tool steel technology occurs on two fronts—developing superior alloys, and refining production techniques:

New steel alloys

Metallurgists continue formulating tool steel alloys with enhanced properties. Some focus areas:

  • Improving heat resistance for accelerating machining speeds and throughput
  • Increasing hardness for longer tool life and sharper cutting edges
  • Optimizing toughness to withstand heavy interruptions and abuse
  • Enhancing corrosion resistance for molding and forming reactive materials
  • Reducing specific alloys like cobalt to control material costs
  • Microalloying with elements like vanadium and niobium to refine the steel’s grain structure for strength
  • Powder metallurgy utilizes fine metal powders to allow highly alloyed compositions impossible through ingot metallurgy. PM process also creates ultra-uniform microstructures.

Production processes

Refining how tool steels are manufactured also produces improved grades. Techniques like:

  • Vacuum processing to reduce impurities and pinpoint alloying additions
  • Electroslag remelting to remove inclusions and improve homogeneity
  • Secondary remelting of ingots to enhance uniformity in larger cross sections
  • Direct aging treatments to optimize toughness and ductility
  • Computer modeling of cooling rates and microstructures helps perfect heat treating for specific tool steels

Tool steel producers continue honing melting, casting, shaping, and heat treating methods. This elevates steel quality and capabilities over each generation.

Cutting-Edge Tool Steel Applications

Tool steels enable shaping and machining applications not previously possible. Some examples at the leading edge:

Luft- og rumfart

Aircraft engines operate under extreme heat and stress. New nickel-based superalloys and hardfacing coatings allow jet engine components to withstand higher temperatures and last longer between overhauls.


Bilproducenterne kræver procesforbedringer og lettere materialer. Værktøjsstål former lettere aluminiums- og kulfiberstykker og producerer komponenter hurtigere gennem højhastighedsbearbejdning.


Støbning af de små, vinklede funktioner på smartphone- og tablet-etuier kræver højglanspolerede værktøjsstålforme med præcisionsdetaljer. Tolerancerne kan være inden for 5 mikrometer.


Delikate kirurgiske værktøjer og instrumenter fremstillet af 420 og 440C rustfrit værktøjsstål sikrer præcis formning og skæring af knogler, væv og kropsmaterialer.


Zink-, aluminium- og magnesiumstøbning kræver værktøj, der kan modstå smeltet metal og samtidig producere millioner af komplekse støbninger med høj tolerance. H13 er et populært valg af formstål.


Når der skal bores mange kilometer dybt for at udnytte olie- og naturgasreserver, kræver det specialbor, der anvender værktøjsstållegeringer med højt koboltindhold og wolframkarbidskær. Stålet kan modstå enorm varme og trykbelastninger.

Disse eksempler viser, hvordan værktøjsstål er grundlaget for mange førende produktionsresultater. Uden værktøjsstål, der producerer bor, forme, matricer og skæreværktøjer, ville sådanne processer være umulige. Efterhånden som værktøjsstål bliver bedre, bliver det muligt at skubbe grænserne endnu længere.

The Future of Tool Steels

Stål til plastforme

Fremskridt inden for værktøjsstålteknologi vil åbne nye grænser for produktionsmulighederne. Nogle muligheder i horisonten:

Bearbejdning på kanten

Nye værktøjsstållegeringer og belægninger vil øge skærehastighederne endnu mere og håndtere mere aggressive bearbejdningsparametre. Det kan muliggøre højhastighedsbearbejdning af hårdere metaller som rustfrit stål og titanium.

Additiv fremstilling

Pulvermetallurgiske værktøjsstållegeringer kan gøre det muligt at 3D-printe færdige værktøjskomponenter med overlegne kvaliteter. Komplekse værktøjsgeometrier, der ikke kan opnås gennem bearbejdning, kan være mulige.

Nanostruktureret og gradientværktøj

Nanokornet værktøjsstål og gradienter i sammensætningen kan optimere stålets egenskaber præcis, hvor det er nødvendigt i et værktøj. Det kan føre til færre nødvendige legeringselementer og dermed omkostningsbesparelser.


Indbygning af sensorer i værktøjet kan muliggøre realtidsovervågning af værktøjets tilstand og emnets kvalitet under produktionen. Det åbner muligheder for forudsigelig vedligeholdelse og adaptiv bearbejdning.

Formning af ethvert materiale

Mere robust værktøj kan udvide antallet af materialer, der kan præcisionsbearbejdes eller støbes. Alt fra kompositter og gummi til glas og keramik kan blive levedygtige emnematerialer.

Værktøjsstål er i en førsteklasses position til at muliggøre nye gennembrud inden for produktion. Fremtiden ser lys ud med hensyn til at udnytte disse uundværlige metaller endnu mere.

Vigtige pointer om Tool Steels

Værktøjsstål er uvurderligt i fremstillingsindustrien:

  • Unikke egenskaber som hårdhed, slidstyrke og dimensionsstabilitet gør det muligt at forme dem til værktøj.
  • Nøje kontrol med legering og produktion giver værktøjsstålkvaliteter, der er optimeret til forskellige anvendelser.
  • Kategorierne er skræddersyet til koldt arbejde, varmt arbejde, højhastighedsskæring og støbning.
  • Et omhyggeligt valg tager højde for serviceforhold, præcisionsbehov, produktionsvolumen, omkostninger og tilgængelighed.
  • Udvikling af overlegne legeringer og perfektionering af forarbejdningsmetoder forbedrer fortsat værktøjsstålets ydeevne.
  • Banebrydende værktøjer og forme fremstillet af værktøjsstål muliggør nye mirakler inden for produktion.
  • Fremskridt lover bearbejdning ved uudnyttede hastigheder, 3D-printet værktøj, nanostrukturerede metaller, intelligente komponenter og udvidede materialemuligheder.
  • Værktøjsstål vil fortsat være afgørende for at flytte grænserne for produktionsmuligheder.

De unikke egenskaber ved værktøjsstål gør det til et magisk materiale for værktøjsmagere. Dette alsidige metal er klar til at hjælpe producenterne med at forme fremtiden. Ved at afdække værktøjsstålets indre funktioner får vi indsigt i, hvordan det opbygger den moderne verden omkring os. Værktøjsstål er i sandhed på forkant med innovation.


What are tool steels?

Værktøj stålrefererer til en række legerede ståltyper, der er designet specifikt til brug i produktionsværktøjer og -forme, herunder skæreværktøjer, forme og matricer til formning af andre materialer. De er konstrueret til at modstå de ekstreme kræfter, temperaturer og slid, der opstår under bearbejdning, støbning, stansning og andet fremstillingsarbejde. Nøgleegenskaberne omfatter hårdhed, slidstyrke, sejhed og dimensionsstabilitet.

How is tool steel made?

Værktøjsstål starter med en base af jern og kulstof. Legeringselementer som wolfram, krom, molybdæn, vanadium og kobolt tilsættes for at give de ønskede egenskaber. Stålet smeltes og støbes til billets eller ingots og smedes derefter til stangmateriale eller andre former. Varmebehandlingstrin som slukning og hærdning giver hårdhed, styrke og mikrostruktur, som giver værktøjsstål deres unikke egenskaber.

What are the main types of tool steels?

Nogle almindelige kategorier omfatter:

  • Stål til koldbearbejdning - Til skæring, stansning, bukning og klipning ved stuetemperatur. (A2, D2, D3)
  • Varmbearbejdningsstål - bevarer hårdheden ved høje temperaturer til trykstøbning og varmformning. (H13, H21)
  • Højhastighedsstål - Hårdhed til skæreværktøjer og bearbejdning ved høje hastigheder. (M2, M4)
  • Formstål - Optimeret til bearbejdning af formhulrum og korrosionsbestandighed. (P20, 420 rustfrit)
  • Stødbestandigt stål - Modstår slagbelastninger. (S7)
  • Vandhærdende stål - maksimerer hårdheden. (W1, W2)
  • Stål med højt kulstofindhold/højt kromindhold - Ekstrem hårdhed ved luftkøling. (52100)

How are tool steels used in manufacturing?

Værktøjsstål bruges til at skabe alle former for værktøj:

  • Skæreværktøjer - bor, gevindskærer, fræser, savklinger
  • Stempler - til stansning, udstansning, bøjning, formning
  • Støbeforme - til støbning, sprøjtestøbning, smedning, glasstøbning
  • Målere, jigs, fixturer - Til fastholdelse og måling af dele
  • Extrusion and drawing dies – For creating wire, rod, tubing
  • Rolls – For shaping, bending, forming sheet metal and plate

How are tool steels selected for an application?

Important factors when selecting tool steels include:

  • Operating temperatures, stresses, and wear mechanisms
  • Dimensional accuracy and surface finish requirements