Tool Steel O1

Tool steel O1 is an oil-hardening, non-deforming tool steel that belongs to the cold work tool steel group. It has high wear resistance, good dimensional stability, toughness, and machinability.

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Tool steel O1 blanking die block on dark workshop table

1.2510
100MnCrW4
T31501
AISI O1
SKS3

640-720 MPa

Ultimate Tensile Strength
400 MPa

Yield Strength
190 GPa

Young's Modulus(Elasticity)
20 %

Elongation at Break

At a Glance

Material Type
Metal
Material Name
Tool Steel O1
Alternative Names
1.2510 | 100MnCrW4 | T31501| AISI O1 | SKS3
Process Compatibility
CNC Milling, CNC Turning

Properties Table of Tool Steel O1

Properties

Ultimate Tensile Strength 640-720 MPa
Yield Strength 400 MPa
Young's Modulus(Elasticity) 190 GPa
Elongation at Break 20%
Physical Properties
Magnetism Magnetic
Weldability Poor
Thermal Properties
Maximum Service Temperature 165-215°C
Thermal Expansion Coefficient 11.3-11.8 x 10^-6/°C
Thermal Conductivity 41.2-44.6 W/(m·°C)
Electrical Properties
Electrical Resistivity 24.5-30.2 μΩ*cm

Applications of Tool Steel O1

Cutting knives
Dies for blanking and forming
Thread rolling dies
Injection molding dies
Woodworking chisels
Carving tools
Drawing and extrusion tools
Precision measuring tools

Advantages of Tool Steel O1

Excellent wear resistance
Good toughness for impact resistance
High hardness for sharp cutting performance
Simple heat treatment process
Good dimensional stability during heat treatment
Versatile applications in cold work tooling, dies, punches, and knives
Ease of machining, contributing to cost savings
Good polishability for smooth surfaces

Raw Stock

CNC Machined

Finished Parts

Tool Steel O1 — Machining Notes

Tool Steel O1 in CNC Mac
is Tool Steel O1?

Tool Steel O1 in CNC Machining

Tool steel O1 is an oil-hardening, non-deforming tool steel that belongs to the cold work tool steel group. It has high wear resistance, good dimensional stability, toughness, and machinability.

O1 tool steel has good machinability but may require slower speeds and feeds compared to some other tool steels. CNC machining of O1 steel often involves pre- or post-machining heat treatment. The material is typically supplied in an annealed condition and needs to be hardened for use in tool applications. The usual heat treatment involves austenitizing at a specific temperature, followed by quenching in oil to achieve the desired hardness. When machining O1, we use carbide inserts because of their hardness and wear resistance. We also use high-speed steel (HSS) tools for less demanding conditions.

We carefully select cutting tool geometry and coatings to enhance tool life and surface finish. We put adequate flood coolant and lubrication to dissipate heat and enhance tool longevity. We regularly monitor tool wear during machining and make adjustments to cutting speed, feed rate, and depth of cut as needed to preserve optimal tool performance. O1 tool steel generally yields a good surface finish when machined correctly. Depending on the application, post-machining operations such as grinding or additional heat treatment may be required to achieve the desired material properties.

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What is Tool Steel O1?

Tool steel O1 is a type of tool steel that hardens when exposed to oil and maintains its shape. It does not shrink during the hardening process, and its composition, including tungsten and higher chromium content, enhances wear resistance compared to other manganese grades.

O1 steel is known for its strength, hardness, and wear resistance. It comes in standard and flat ground stock, as well as drill rod forms.

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FAQ

Will O1 tool steel rust?

Like many tool steels, O1 is prone to rusting if not properly cared for. Keeping the steel dry, clean, and coated with a rust inhibitor or oil is recommended to prevent rust. Regular maintenance and storage in a controlled environment can help mitigate the risk of rusting.

Can O1 steel be welded?

While O1 tool steel can be welded, it is not considered a readily weldable steel due to its high carbon content. The high carbon content makes it prone to cracking during welding. Preheating and post-weld heat treatment are often necessary to minimize the risk of cracking.

How do you harden O1?

O1 tool steel is typically hardened through a process known as oil quenching. The general procedure involves heating the steel to a specific temperature range (typically around 1450-1600°F or 788-871°C), holding it at that temperature for a sufficient time to ensure uniformity, and then quenching it in oil. The oil quenching process helps achieve the desired hardness and toughness in O1 tool steel. Subsequently, the steel is usually tempered to reduce brittleness and achieve the desired balance of hardness and toughness.

What is the difference between O1 and W1 tool steel?

O1 tool steel is an oil-hardening steel containing a higher alloy content, including chromium and tungsten. This makes O1 more wear-resistant and provides better hardening capabilities compared to W1. W1 tool steel, on the other hand, is a water-hardening steel with a simpler composition. It has a high carbon content and is used for applications where water quenching is preferred.