AISI O2 Tool Steel | 1.2842: Properties, Heat Treat, Uses

O2 tool steel is a trusted material for industries that require high strength and long-lasting performance. At SteelPro Group, we pride ourselves on offering high-quality O2 tool steel products, ready to meet the unique needs of your projects. 

In this article, we’ll take a closer look at O2 tool steel, its properties, applications and how heat treatment can boost its performance. Let us help you know more about O2 tool steel.

What is O2 Tool Steel?

O2 tool steel is a high-carbon, cold-work alloy commonly available in shapes such as round bars, flat bars, and occasionally plates. Recognized for its exceptional hardness, durability, and strength, O2 is frequently used in cutting tools, punches, and dies. After heat treatment, it achieves a hardness of 55-60 HRC, making it ideal for cold-working applications.

Standards And Equivalent Grades of O2 Grades

Comprehending the standards and equivalent grades of O2 tool steel is crucial for choosing the appropriate material for your projects. Below, SteelPro Group offers a clear overview of its equivalents and different global standards:

Chemical Properties of O2 Steel

O2 tool steel’s chemical composition gives it a strong balance of hardness, wear resistance, and toughness. Its high carbon content helps with edge retention, while chromium and manganese improve strength and hardenability. 

Here is a quick look at the chemical composition of O2 tool steel.

Mechanical Properties of O2 Steel

O2 tool steel is known for its high hardness, excellent tensile strength, and resistance to deformation. It has low elongation and solid impact resistance, making it a durable material under stress. SteelPro Group ensures each batch of O2 steel is carefully processed to maintain these properties, providing the material that performs consistently across various applications.

The table below summarizes the key mechanical properties of O2 tool steel.

• Hardness, Knoop is converted from Rockwell C hardness.

Physical Properties of O2 Tool Steel

O2 tool steel has a high melting point and good thermal conductivity, making it well-suited for high-temperature applications. Its moderate coefficient of thermal expansion helps it maintain stability during heating and cooling, reducing the chances of distortion. 

The table below highlights the key physical properties of O2 tool steel.

Fabrication And Heat Treatment of O2 Tool Steel

Forging

O2 tool steel is heated at temperatures between 1000°C and 1100°C (1832°F to 2012°F). If the steel has been heavily deformed or worked, it may need to be reheated within the 850°C to 1050°C range to restore its workability.

Annealing

O2 is heated to 800°C to 850°C (1472°F to 1562°F), followed by a slow cooling process in a furnace. If the steel is to be further worked or machined, a second annealing may be needed to relieve stress from prior processing. 

This process helps reduce internal stresses, refine the grain structure, and improve machinability. After annealing, the hardness typically drops to around 220-250 HB. For fully processed cutting tools made from O2, filling the cavity during the annealing process ensures uniform hardness across the tool.

Hardening

O2 tool steel is first heated to 780°C to 850°C (1436°F to 1562°F) then quickly cooled in oil to achieve hardening. For every 25 mm (1 in) of thickness, the material should be held at the hardening temperature for at least 30 minutes to ensure uniform heat treatment.

Preheating to 300°C to 500°C (572°F to 932°F) may be necessary for thicker sections.

Martempering

This involves cooling the steel in a medium such as oil or molten salt at a controlled rate to a temperature just above the martensite start point. Then cool the teel.

Martempering is used to reduce internal stresses and prevent cracking in thicker sections of O2 tool steel. It can still achieve high hardness.

Tempering

For O2 tool steel, tempering is typically done at temperatures between 150°C to 500°C (302°F to 932°F). The steel should be held at the tempering temperature for at least one hour per inch of thickness to ensure uniformity. 

Tempering is essential to adjust the hardness and improve toughness after hardening or martempering.

SteelPro Group can offer O2 tool steel in a variety of states to meet your specific needs. We offer it in the machinable (annealed) state, which makes it easier to work with, as well as in the quenched and tempered state, ideal for applications requiring higher strength and durability. 

Product Forms of O2 Tool Steel

Below are the standard specifications for O2 tool steel products that SteelPro Group offers. 

We provide a wide range of O2 tool steel in various forms and sizes to meet different industrial needs. If you require custom sizes outside of the typical range, we can accommodate your specific requirements!

Round Bars

• Diameter: 10 mm to 300 mm (0.4 inches to 12 inches)
• Length: 1000 mm to 4000 mm (39 inches to 157 inches)

Flat Bars

• Thickness: 5 mm to 100 mm (0.2 inches to 4 inches)
• Width: 50 mm to 400 mm (2 inches to 16 inches)
• Length: 1000 mm to 4000 mm (39 inches to 157 inches)

Plate

• Thickness: 10 mm to 100 mm (0.4 inches to 4 inches)
• Width: 200 mm to 800 mm (8 inches to 32 inches)
• Length: 1000 mm to 4000 mm (39 inches to 157 inches)

Rod

• Diameter: 5 mm to 50 mm (0.2 inches to 2 inches)
• Length: 500 mm to 2000 mm (20 inches to 79 inches)

Applications of O2 Tool Steel

O2 tool steel is primarily used in industries where tools need to be durable, wear-resistant, and able to withstand mechanical stress. It is most commonly found in manufacturing processes. The following are some of the key applications of O2 tool steel.

Cutting Tools

O2 is great for making cutting tools like blades, drills, and reamers. Its hardness helps these tools stay sharp and last longer, even with heavy use.

Blades and Shears

Blades and shears made from O2 tool steel are known for holding their edge well, making them ideal for cutting through tougher materials without wearing out quickly.

Saws and Slitting Tools

O2 is also used in saws and slitting tools. Its ability to maintain strength and performance under pressure means these tools stay effective longer, even in high-demand situations.

Cold Work Dies and Punches

Because of its wear resistance, O2 is often used for dies, punches, and stamping tools that need to endure repeated impact and friction during metal shaping.

• Is O2 Good Knife Steel?

Yes, O2 tool steel is excellent for knives. It offers great hardness and edge retention (55-60 HRC after heat treatment), making it ideal for durable, sharp blades. While not stainless, it’s tough and holds up well under heavy use, as long as it’s properly cared for.

Your Trusted Source for O2 Tool Steel

At SteelPro Group, we know that the right material can make or break your project. That’s why we offer O2 tool steel in various forms, including round bars, flat bars, and plates, all tailored to meet the specific demands of industries like manufacturing, automotive, and tooling. If you require stronger materials, we can also provide other cold work tool steels.

With fast shipping, flexible ordering, and personalized service, we’re committed to supporting you every step of the way. We are not just a supplier; we’re your partner in making sure your tools and machinery perform at their best.