If you've ever dealt with scrap metal processing, chances are you've encountered tool steel—and immediately understood why it's such a headache. That extreme hardness that makes tool steel perfect for manufacturing is exactly what makes it nearly impossible to cut when it reaches end-of-life.
In this article, I'll walk you through the characteristics of tool steel, explain where that notorious hardness comes from, and share a real-world case study of cutting a thick tool steel die using a Ø17.3mm thermal lance. If you're struggling to break down worn stamping dies, molds, or tool steel components, this might be exactly what you need.
Tool steel belongs to one of four major steel categories, alongside carbon steel, stainless steel, and alloy steel. But what sets tool steel apart is its exceptional hardness—and understanding where that comes from is key to understanding why it's so difficult to cut.
Tool steel's extreme hardness comes from two critical factors:
Tool steel contains high carbon content (0.7-2.3%) plus additional alloying elements:
These elements don't just make the steel hard—they create ultra-hard carbide particles distributed throughout the material, acting like embedded ceramic reinforcements.
The real transformation happens during heat treatment:
Austenitizing -> Quenching -> Tempering
This process creates a unique microstructure where smaller grains with more boundaries make it incredibly difficult for cracks to propagate—giving tool steel both its hardness and toughness.
The result? A material that's perfect for cutting other metals but becomes your worst nightmare when you need to cut it.
Tool steel is extremely difficult to cut due to three critical properties:
To overcome these challenges and cut tool steel effectively, you must:
This is exactly what thermal lance achieves at 3,600°C—hot enough to melt and oxidize even the hardest tool steel grades, making it the most effective solution for cutting hardened tool steel.
Today, we're sharing a real-world case study demonstrating thermal lance cutting performance on a hardened tool steel die.
Our target cutting material is a cold-work tool steel die made from SKD61 grade steel, previously used in stamping/pressing operations.
Material Specifications:
Based on our engineering team's assessment, for this large rectangular metal block with complex machined grooves, we selected a Type T Thermal Lance configuration.
Why Type T?
Why Ø17.3mm (3/8 inch) diameter?
Industry-standard dimension for ease of use
Below is our cutting test footage demonstrating the complete thermal lance operation on the SKD61 tool steel die.
Below are the preliminary test results recorded by our Daiwa Lance engineering team, along with visual observations from the SKD61 tool steel die cutting test using Ø17.3mm thermal lance.
Operating Parameters & Results:
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Visual Inspection |
Preliminary Analysis |
| Deep and Wide Cut Path |
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| Heavy Surface Oxidation |
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| Molten Metal Flow and Solidification |
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| Material Combustion at Direct Contact Zone |
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While the cut surface is not as smooth or precise as CNC machining or plasma cutting, the ability to break down extremely thick and hard material through intense thermal-oxidation reaction is absolute.
Thanks to this capability, thermal lance overcomes the limitations of all conventional cutting methods, making it possible to separate or dismantle tool steel dies with very high hardness that would otherwise be nearly impossible to process.
We've demonstrated the cutting effectiveness of thermal lance Type T Ø17.3mm on hardened tool steel SKD61 through real performance testing. The results clearly show that thermal lance provides a reliable, efficient solution for processing end-of-life tool steel dies and components that resist conventional cutting methods.
Contact us if you'd like to know more about:
・Safety Preparation: Step-by-step safety procedures for cutting tool steel dies with thermal lance
・Oxygen System Setup: How to configure your oxygen kit for strong, evenly distributed flame before cutting
・Ignition & Flame Management: How to ignite thermal lance properly, or techniques to maintain flame and prevent extinguishing during operation
・Live Performance Videos: Watch actual thermal lance cutting demonstrations and See complete cutting operations from start to finish