HPS® steel for knife applications

27 November 2018 Author : 

HPS® steel, patent of AG STEELS (owner and unique distributor of this material) is known for its excellent toughness and incredible wear resistance.

It is a steel used in the production of high performance cold working tools and is composed of a precise combination of chrome, vanadium and molybdenum.

The main uses of HPS:

  • high performance punches and dies
  • circular blades
  • straight blades
  • blades for shears
  • tools for pressing and threaders

Some time ago I was contacted by AG STEELS, a company specializing in trade and distribution of special steels, which asked me to test the use of HPS steel in knives field.
I decided then to involve the CIC Master Piero Petronzio, to whom I entrusted the steel plate with the purpose of creating a knife and a compact axe.

During the knife making phases, Master Petronzio found a certain difficulty in grinding the blade, given the high wear resistance of the material. Below the considerations made by the knife maker:
During roughing of the annealed material (about 28 HRC), the steel is clean and compact; it shows already a remarkable resistance to abrasion in this phase. Furthermore, during processing it is possible to immediately see the low resistance to oxidation, as expected from the composition of the steel.
The heat treatment, carried out by a specialized company, as for many modern steels, is rather long and laborious (and therefore expensive). The steel was hardened to 60 HRC in the 2nd curve with 3 tempering phases. Although it has been hardened to a lower hardness that the material can reach (64 hrc), it has a notable wear resistance compared to other steels (the material consumes with considerable speed the large and medium-grained ceramic abrasive belts). Even the final finish is quite difficult, so it would be better to reduce to a minimum possible all the working phases after steel hardening.

The fatigue in handcrafting this steel is however repaid by the quality of the material: after the very first tests conducted on the knife, directly from Master Petronzio, the steel has shown a high cutting edge retention and resistance to chipping, even after carrying out tests on wood. Among the non-stainless steel, the HPS goes in terms of quality, among those of very high end, and is comparable with the K360 isodur, and gives the feeling of being better than the Sleipner. For lovers of carbon steels, HPS is definitely a material to consider.

The small axe, designed and handmade by the knife maker, has a 140 mm long head with a cutting edge of 70 mm. The design, reminiscent of Winkler's style, was designed with the aim of creating a multirole axe of compact size; the instrument has a total length of 270 mm, an average thickness of about 7 mm (tapered towards the end of the handle at 4.6 mm), and a weight of 570 g.

The first portion of the handle shows a stone pattern that not only makes the instrument aesthetically appealing, but also improves its grip. The handle consists of two Micarta scales and is characterized by the presence of comfortable finger grooves.

Before proceeding to test the tool made by Master Petronzio, it is necessary to make a premise: the cutting performance of a knife is a function not only of the composition of the steel and of the heat treatment it has undergone, but also of the geometry with which the blade is made. In this regard, to be able to quantitatively test a steel and compare it with others, it would be necessary to make standard specimens for each steel (thus eliminating the "geometry" variable), and proceed to the tests according to scientific method, perhaps evaluating a range of hardness (for this reason I always believe that the various comparison tables on steels performance that you can find online are not reliable and true at all).

Since it is not possible for me to conduct a quantitative test according to the scientific method, I will have to limit myself to making qualitative considerations and comparisons with other steels solely on the basis of my personal experience.

The considerations will follow soon, after tests that will be conducted within a month of use.

The knife and one of the compact axes created by Master Petronzio will be exhibited during the CIC Show, on 1 and 2 December in Milan.


HPS steel producer: AG STEELS - /www.agsteels.it

Knife Maker: Piero Petronzio

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