Powdered High-Speed Steel - Stainless Steel

High-Speed Steel (HSS) was originally developed as a tool steel for applications like drills, designed to maintain hardness even at high temperatures.

However, due to its coarse metal structure, it was considered unsuitable for knives, which require cutting across the entire blade and maintaining sharpness by sharpening the entire blade. It didn't work for tools like knives that required and kept sharpness.

The introduction of powder metallurgy has revolutionized this material, however, allowing for fine particle processing. This improvement makes it suitable for knives, as it can now have both sharpness retention and, to an extent, ease of sharpening.

Its remarkable feature is its extremely high hardness. A blade made of sharp Powdered High-Speed Steel can effortlessly cut through ingredients while applying only minimal force.

However, it's important to remember that the cutting ability of a knife is not solely determined by the sharpness of its edge. Extremely hard knives can be prone to chipping or other breakage. To achieve a balance, many additives are incorporated, often sacrificing ease of sharpening and rust resistance.

Describing it as 'popular for hunting knives and tool steel' may make it clearer. It's favored in uses where resistance to chipping is crucial, and the need for delicacy, such as slicing sashimi, is not a priority.

There are different types of Powdered High-Speed Steel that are used in the culinary knife industry. Consider it a subcategory, much like stainless steel or carbon steel - even though in itself Powdered High-Speed Steel is a stainless steel. As confusing as it is, it is a subcategory in a subcategory (Steel -> Stainless Steel -> Powdered High-Speed Steel.)

Just having a high hardness alone means it won't interact well with sharpening stones. Sharpening these knives is simply put, tricky at best. Achieving the delicate balance of extracting the thickness to bring out sharpness while maintaining enough strength to withstand impacts raises the difficulty level significantly for knifemakers as well - and thus the labor costs associated with creation.

In other words, knives made of this steel can end up being surprisingly expensive yet prone to chipping and challenging to sharpen.

Despite all this, there are steel types that possess the characteristics of Powdered High-Speed Steel while also offering the necessary ease of sharpening, resilience to impact (like drops or strikes,) and rust resistance required for culinary knives. These include styles like SG2 (Super Gold 2)/R2, ZDP189 or SRS15.

The specific characteristics of each will be explained in the composition section of this blog, but it's important to note at minimum that there are differences.

Steel material is crucial for indicating a knife's initial performance (amongst many other things related to craftsman ability and more). Below are some comparisons to give you some understanding showing what a particular step of the process does in terms of impacting sharpness, balance and maintainability.

There’s three key pointers in the above chart to focus on.

• Steel Material has a large impact on sharpness and maintainability (ease of sharpening and resistance to rust).

• Apart from sharpness, heat treatment and the sharpening process in knife creation also have a large impact on sharpness.

• Measuring a knife’s strengths is more than just its sharpness. Balance and maintainability also need to be considered.

Based on the above steel mapping chart, Super Gold 2/SG-2/R2 Steel falls in this position on the graph below. Note that other Powdered High-Speed steels may fall elsewhere.

Extremely high hardness and sharpness, at the cost of an equally high wear resistance

Let’s look at the tables below and explore the composition of various Powdered High-Speed Steels more deeply. Pay attention to the secondary materials, as well as the carbon and chromium content of these steels.

The hardness of this steel exceeds 60, placing it in a category of knives with a significantly high level of hardness. With substantial additions of Molybdenum (Mo), Vanadium (V), and Chromium (Cr), it exhibits high tenacity and wear resistance in addition to the sharpness it provides.

In other words, it possesses a characteristic of being less susceptible to grinding down from sharpening stones, making it suitable for those who want to explore various types of whetstones and sharpening techniques to see what works best for them, with relatively less punishment for mistakes (bar chipping if you are not careful).