OYO knives and steel quality

Do you want to choose a quality knife? The quality of the steel is one of the main parameters when choosing it. Read more about this topic in our blog.

Steel quality

When choosing steel, properties such as durability of sharpness, ease of maintenance and sharpening, and last but not least, the price and availability of the steel are taken into account. All of these practical properties are inextricably linked to the hardness of the steel. For Øyo, quality steel is primarily about the balance between the duration of the knife's sharpness - how long it lasts before it becomes dull - and the ease of resharpening it. For a large part of our knives, we have therefore chosen a steel hardness that we believe is appropriate given this balance.

Rockwell

The Rockwell scale (HRC) provides an objective measure of quality that describes the hardness of steel. The harder the steel, the stronger the material. The Rockwell scale is an international hardness scale that indicates the surface hardness of a metal. There are several scales, A, B, C, D, E, F, G, H, K, N and T. The most commonly used scales are B and C and are called HRB and HRC respectively. The scale used to measure the hardness of a material in knives is HRC.

The quality of the steel used to make knives helps determine how hard the steel can be, and consequently what HRC can be achieved. Different hardening will therefore give the knife steel slightly different properties.

There are several variables that can change this relationship. One is the alloy itself, and another is whether the knife is forged or pressed. A forged knife will have relatively much higher material strength at lower HRC values. This means that Rockwell must be considered in relation to the steel grade, the alloy, and whether the knife is forged or pressed.

Knife steel that is hardened above 57–58 HRC can cause the material to become brittle. With the thin 20–30 micron blade edge that is common for most steel knives, proper hardening is important. Softer steel will cause it to bend, and harder steel can cause it to break. Material that has bent can be straightened with a sharpening steel, while broken material needs to be removed enough material to restore the 20–30 micron edge. This process usually involves grinding or using a coarse grinding steel or diamond steel. This leads to cracks during sharpening and a less sharp edge.

Steel grades

To make it easier for you to decide on the quality of the steel of your Øyo knife, we have decided to divide our knives into 3 different steel categories: Standard steel, Premium steel and Exclusive steel. All knives will be marked with which category the specific product belongs to, making your choice easier.

Standard steel

Quality is important to us regardless of price, but steel will change a lot from standard steel grade to premium steel grade. Standard steel has a softer steel and requires frequent sharpening to keep the blade sharp. In return, the edge will be very easy to sharpen. Øyo knives with the standard steel category will have a grinding degree of 20 degrees and the steel is hardened to approximately 52–55 HRC. Steel grades that fall into this category are e.g. 3Cr steel, 420.

Premium Steel

You get a lot of steel for your money here, and for most people, this is a very good choice. The steel is soft enough that you can sharpen the blade yourself, but hard enough that you don’t have to do it as often (depending on how often you use the knife, of course). The edge is set at 20 degrees and the steel is hardened to around 55–57 HRC. Steel grades that fall into this category include 5–8Cr, 4116, 440A/B, AUS6–8, 13C26.

Exclusive Steel

This is where the quality of the steel comes into play, which is truly exceptional. On kitchen knives, you get a much thinner blade that makes cooking a breeze. In the outdoors, you get full-length knives that are extremely durable. In kitchens, the blade is set at 16 degrees and Damascus knives have a hard core and a softer steel layered on the outside. Again, this quality of steel will not be suitable for hard (e.g. bones) or frozen foods, but exceptional for soft foods. The blade may be a little more difficult to sharpen yourself, but in return, you will have a sharp edge for a very long time. The steel is hardened to around 58–62 HRC. Steel grades that fall into this category are 9Cr, 440C, AUS10, 14C28, VG10.