Tool Steel Investment Casting - In the Field
Welcome to another edition of In the Field, where we learn about different alloys used in metalworking and explore some of their strengths and usage scenarios. Today, we're exploring one of the most ubiquitous examples of cast metal: tool steels!
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Also, don't forget to check out our previous articles on Stainless Steel Castings and Aluminum!
Let's get into it!
Tool steels are ubiquitous and offer tons of flexibility to meet specific usage scenarios.
What is Tool Steel?
As the name suggests, tool steels are any carbon or alloy-based steel especially suited for making tools. So, what makes a tool great? In short, high performance in its intended application.
A Frustrating Real-Life Example
Maybe you've had a boiling-point-inducing experience of camping with cheap tent stakes. I'll paint a picture: it's 7:30 pm, and you just pulled into camp. You have about 30 minutes until it is dark; above all else, you want to get your tent up before pitch black out. Laying out the tent is easy enough, and soon you've got your tent poles lined up, and you're ready to stake down the tent. Crap, you think to yourself, you didn't bring a hammer.
First, you try to push the stake with your hand, but all that does is hurt your palm. Next, you try the classic gravity technique by stepping on the stake; it bends, and now you are out of a tent stake. You look for a rock to hammer the remaining stakes into place as a last-ditch effort. Much like your foot before, even a perfectly sized rock ends up bending the stake, and instead of stakes, you end up holding your tent corners down with rocks.
You're in for a rough night of sleep in the wind and a trip to your local outdoor shop for a better set of stakes when you get home. Even a hammer may not have saved you from these cheap, flimsy stakes.
The tool didn’t stand up to the job at hand, and you are left hanging because of it.
Back to the Point
As a professional or a consumer, you want your tools to be durable and to perform the task at hand. In investment casting, foundry workers pair steel with numerous other metals, such as chromium, vanadium, molybdenum, and tungsten, to facilitate its hardness and other desirable properties. Different types of tool steel are chosen based on the intended use of the tools when in the field. Typically, this means balancing five things: hardness, wear resistance/durability, toughness, heat resistance, and corrosion resistance.
Hardness: Tool steel is hardened through heat treatment to achieve high hardness levels, allowing it to effectively cut and shape other materials.
Wear Resistance: Many tools must resist abrasion and wear, making them durable and long-lasting in environments with repeated use.
Toughness: Revisiting our camping example, tool steels must also possess a degree of toughness, an essential component for withstanding impacts and preventing breakage during use.
Heat Resistance: Certain tools must retain their hardness and strength at elevated temperatures, making them suitable for high-heat applications, like saw blades or drilling.
Corrosion Resistance: While not as corrosion-resistant as stainless steel, some types of tool steel are formulated to resist corrosion.
When choosing your ideal tool steel, you need to weigh each of these factors and determine your needs.
Drill bits are commonly made from High-Speed Tool Steels so they can perform precision work without failure at high temperatures.
What are Common Types of Tool Steels?
There are several common types of tool steel. We'll explore the main categories below and discuss a few potential usage scenarios.
High-Speed Tool Steel (Commonly M-Type):
As the name suggests, these tools operate at high speeds, think drill bits, saw blades, or milling cutters. High-speed tool steels like M2 and M42 contain tungsten, molybdenum, and vanadium. These elements allow them to maintain hardness at high temperatures and provide consistent, accurate results.
Cold Work Tool Steel (O-Grade, D-Grade, A-Grade):
Cold work tool steels are all about performance in applications at or near room temperature. These steels are characterized by their excellent wear resistance, toughness, and ability to withstand mechanical stress without significant softening. You'll commonly find cold work steel in cold forging, bending, and stamping operations. It is also commonly seen in blades, knives, and other cutting tools.
Within Cold Work steels are three primary types or grades: O, D, and A.
O-Type:
O-grade steel stands for oil-hardening tool steels. These undergo oil quenching during heat treatment. The oil treatment results in a favorable balance of hardness and toughness, making O-Type suitable for various cutting tools, knives, and punches.
D-Type:
D-type tool steels are a category of high-carbon, high-chromium tool steels known for their excellent wear resistance and hardness. This makes them particularly adept in punches, dies, mold components, and woodworking tools.
A-Grade:
This stands for air-cooled tool steels. At elevated temperatures, these steels have excellent wear resistance, hardness, and dimensional stability. Because of these properties, they are incredibly versatile and can be commonly found in dies, shear blades, plastic and rubber molds, stamping dies, and woodworking tools.
Hot Work Tool Steel (H-Type):
Hot work tool steels, such as H13 and H21, are specifically formulated for high-temperature applications like forging and die casting. Its excellent heat resistance and strength at elevated temperatures make it indispensable in such processes. Of note, these steels are not designed for cutting at high temps.
Shock-Resisting Tool Steel (S-Type):
S7, a shock-resisting tool steel, is tailored to withstand high impact or shock loads. Tools made from S7, such as chisels, hammers, and punches, excel when sudden impact is a common occurrence during use.
Water-Hardening Tool Steel (W-type):
Water-hardening tool steel, categorized as W-type, is quenched in water during heat treatment. This imparts high hardness, making it suitable for cutting and woodworking tools.
Special Purpose Tool Steels:
One quick example of a special-purpose tool steel type is the P designation, which stands for plastic mold tool steel. These steels need to have high hardness to resist wear, abrasion, and deformation during molding, as well as heat resistance, corrosion resistance, and polishability.
Ultimately, hundreds of combinations of materials can provide unique properties to your investment casting project, and exploring them all goes beyond the purposes of this blog. If you have unique tool steel needs or want to learn what alloys are available, we recommend contacting a reputable investment casting foundry!
Does IPC Foundry Group Cast Tool Steels?
Yes! The IPC Foundry Group has been pouring tool steels for dozens of industries for over 40 years. Contact Us today if you'd like to speak with one of our dedicated team members!
Disclaimer:The content provided in this blog is intended for informational purposes only. We make no guarantees to the completeness of this information. This blog does not offer manufacturing or casting advice, and readers are encouraged to contact our dedicated team for more detailed quotes, personalized information, and expert assistance tailored to their unique needs. 