Skip to content 
The steel family is huge with multiple alloys. Among them, you may have heard of stainless steel, an alloy widely used in construction and domestic applications. Equally popular is tool steel on the manufacturing side, especially in the machining industries.
Now, in this article, we aim to compare these two steel types across their composition and mechanical properties. The idea is to reveal how distinct the two types are, so you can easily pick the right choice for your needs.
What is Tool Steel?
Tool steel is an engineered carbon alloy steel with exceptional hardness, wear resistance, and toughness. Its alloying elements tungsten, molybdenum, vanadium, and chromium, form carbides. These strongly bonded structures are fully distributed through the lattice and are responsible for its hardness.Tool steel, as in its name, was primarily made for making tools and dies. Due to wear resistance and ability to maintain a sharp edge at higher temperatures, it finds applications in cutting tools i.e. saw blades, drill cutters, end mills, turning tools, knives, etc.
What is Stainless Steel?
Stainless steel is a steel alloy with a minimum of 10.5% chromium content, which entirely shapes it whole physical and chemical characteristics. Other alloying elements – like nickel, titanium, and molybdenum – are also present in certain grades of stainless steel.This steel is best known for its excellent corrosion resistance and aesthetic appeal. So, its use is widespread in everyday applications. In construction, it’s common for handrails and facades. In the auto sector, it’s used for exhaust parts. Due to biocompatibility, it is also used in medical equipment and implants. Cookware is another popular application.
Tool Steel vs Stainless Steel: 6 Differences
The purpose of the materials overview was to give you a quick glance at the best properties of each. Since both alloys include multiple grades, our comparison will focus on the unified properties within each family – though we will try to entertain some of their popular grades in the differences.
1. Chemical Composition
The chemical makeup is what defines the distinguished characteristics of each material. Tool steels have vanadium, nickel, molybdenum, and tungsten as alloys. But it’s not these elements but their ability to form carbide structure throughout the material. These carbides are extremely hard and improve the wear resistance, cutting ability, and longevity of tools.
Although stainless does have multiple alloying elements the key element is chromium – at least 10.5% Cr is present in this class of metals. The chromium forms a passive oxide layer on the surface. This layer acts as a shield against corrosion, regenerating itself when damaged.
Unlike tool steel, carbide formation in stainless steel is minimal. However, due to the high carbon content in some stainless steels, chromium carbide precipitation can occur at grain boundaries. This phenomenon is called sensitization. This is why low-carbon stainless steel grades (e.g., 304L) are preferred in environments requiring durability against rust.
Here’s a detailed breakdown of the chemical makeup of stainless steel and tool steel:
| Tool Steel (%) | Stainless Steel (%) | |
|---|---|---|
| Carbon (C) | 0.5 – 1.5 | < 0.08 (Most grades) |
| Chromium (Cr) | Normally up to 5 (Some grades higher, ~12 | 10.5 – 29 |
| Vanadium (V) | 0.1 – 2 | Rarely present |
| Molybdenum (Mo) | Up to 10 | 0 – 5 |
| Nickel (Ni) | Absent or minimal | 8 – 10 |
| Tungsten (W) | Up to 18 | Not commonly included |
2. Manufacturing Process
Tool steel is made with controlled methods to optimize its hardness, toughness, and wear resistance. Here’s the process journey:
- The raw materials or scrap gets into an Electric Arc Furnace (EAF) which controls the chemical mix-up.
- Ladle refining is carried out for the removal of impurities.
- The molten steel is either ingot cast or continuously cast into semi-finished forms like billets or slabs.
- The steel undergoes hot rolling or forging to achieve the desired dimensions and grain structure.
- Heat treatment processes (annealing, quenching, and tempering) may be carried out.
Stainless steel production focuses on achieving superior corrosion resistance and durability.
- The process starts with melting stainless steel scrap or raw materials in an EAF.
- Argon Oxygen Decarburization (AOD) refining follows, where oxygen and argon gases are injected to reduce carbon content and refine the alloy.
- Steel is continuously cast into slabs, billets, or blooms. These forms undergo hot rolling to reduce thickness and are further processed through cold rolling for precise dimensioning.
- Heat treatment is carried out to relieve stress and enhance ductility. Descaling is done for surface impurities.
- Passivation is applied to strengthen the protective oxide layer, enhancing corrosion resistance.
3. Grades and Types
Tool steel and stainless steel belong to the main steel family, but they further have multiple groups and grades, based on their respective properties and composition.
For tool steel, the classes are primarily based on the hardening method. The table illustrates tool steel grades and their applications.
| Tool Steel Grades | Characteristics | Applications |
|---|---|---|
| Water-Hardening (W) | High hardness Lower toughness Inexpensive | Hand tools, woodworking tools |
| Cold-Work (O, A, D) | High wear resistance Moderate toughness Used at lower operating temperatures. | Dies, punches, tools for cold forming. |
| Hot-Work (H) | High thermal stability Retains hardness and toughness at elevated temperatures. | Die-casting dies, hot forging tools, extrusion tools. |
| High-Speed (M, T) | Retains cutting edge at high temperatures. | Cutting tools like drills, milling cutters, and taps. |
| Shock-Resisting (S) | High impact resistance Moderate wear resistance | Hammers, chisels, shear blades, impact tools. |
| Mold (P) | Good machinability, polishability, and toughness. | Plastic injection molds, die-casting molds. |
In the case of stainless steel, the classification is based on metallurgical structure, composition, and heat treatment. The class of stainless steel and their respective applications are listed in the table.
| Stainless Steel Groups | Characteristics | Applications |
|---|---|---|
| Austenitic | Non-magnetic Excellent corrosion resistance Good weldability and ductility | Kitchen equipment, food applications. |
| Ferritic | Magnetic Moderate corrosion resistance Good formability Lower cost | Automotive trim, appliances, decorative items. |
| Martensitic | Magnetic Heat-treatable High strength and hardness Less corrosion resistance | Cutlery, surgical tools, bearings. |
| Duplex | Balance of ferritic and austenitic properties. | Oil and gas, chemical processing. |
| Precipitation-Hardening | High strength Excellent corrosion resistance Age-hardenable | Aerospace, automotive, structural applications. |
4. Mechanical Properties
The mechanical properties also differ due to their different chemical makeup. For manufacturers properties that matter most include strength, durability, and hardness.
We have repeatedly mentioned the tool steels outshine stainless steel in hardness (up to 70 HRC) and wear resistance. So, their first use case is cutting tools. They do offer great strength but their brittle nature doesn’t make them great for pure structural and load-bearing applications. Another reason is their low corrosion resistance.
On the other hand, stainless steel brings a different set of strengths to the table. Most stainless steel grades don’t match tool steel’s hardness but the hardness is slightly higher in martensitic grades (58 HRC). Moreover, the young’s modulus and comparatively ductile nature make it suitable for load-bearing and structural applications.
Corrosion resistance is what truly sets the stainless steel apart, thanks to its chromium content (>10.5%). It creates a protective oxide layer which makes it rust-free and durable. The following table presents our detailed outlook of mechanical properties of the two metals:
| Tool Steel | Stainless Steel | |
|---|---|---|
| Hardness | High (58–68 HRC) | Moderate (70–90 HRB); up to 58 HRC (martensitic) |
| Tensile Strength | 450 to 2500 MPa | 515–1300 MPa |
| Ductility | Low (more brittle) | High (good ductility) |
| Corrosion Resistance | Poor | Excellent |
5. Machinability
High resistance and hardness mean trouble for tools and challenges in machining but largely most of them are machinable except few grades. For instance, D2 tool steel has a machinability rating of approximately 27%, which hints that it’s more difficult to machine compared to standard carbon steel. However, W1 grade is one of the easiest ones to tackle.
Stainless steel is also challenging to machine, especially austenitic grades like 316. Their low thermal conductivity, ductile nature, and work hardening make them challenging. The machinability rating of grade 316 is about 36%.
6. Price
The price of alloys is based on the alloying elements and manufacturing method. In general, the tool steel is more expensive to due the precise alloying process and expensive treatment. Whereas, stainless steel is relatively affordable and one of the reasons why it’s very common in domestic. The commonly used stainless steel 304 is priced at $0.66/lb.
Tool Steel vs Stainless Steel: Which One’s Right for Your Project
Now, it comes down to selecting the right material for your needs. We have already detailed the specific properties and grades of both tool steel and stainless steel. To further simplify the decision, let’s outline scenarios where each material excels and is most favorable.
Choose tool steel:
- For applications involving cutting, shaping, or forming materials, such as manufacturing cutting tools, dies, and molds, where wear resistance is needed.
- When work involves working at elevated temperatures, for instance, die casting and extrusion processes.
Select stainless steel:
- For projects where appearance and ease of cleaning are important, like architectural facades, medical instruments, and food processing equipment,
- When corrosion resistance is needed i.e. outdoor environments exposed to moisture or equipment exposed to chemicals.
- Medical implants and surgical tools.
Richconn’s Metal Machining Services
Tool steel or stainless, whatever material you choose for your next project, RichConn is here to assist with expert machining services. With decades of experience in metal CNC machining, we deliver precision up to 0.001mm, regardless of the grade you select.
At RichConn, we have state-of-the-art multi-axis CNC and skilled engineers to provide design support. The goal is to ensure your project meets exact specifications. Plus, we offer delivery within 48 hours for most parts.
So, why wait? Just contact us today. You’re just a step away from machining solutions customized to your project’s needs!
