What does a low RC rating on steel mean?
What Does a Low RC Rating Mean? Low RC ratings indicate softer steel composition. Soft steels are malleable, meaning they can bend and deflect better than hard and brittle steel.
Is RC steel too hard to sharpen?
With industrial machine knives, extremely hard steel with an RC number in the 60s may be too fragile to use reliably. High-rated RC hardness steels maintain their edge well, but it’s difficult to achieve sufficient sharpness. Highly durable steel requires sharpening stones made of ceramic or diamond.
What does HRC mean on knives?
Generally, knives are described as having an HRC rating of X. “HR” stands for the Rockwell Scale of Hardness, and the “C” represents part C of the scale. The Rockwell Scale is used to determine the hardness of a material, and part C specifically refers to steel. The hardness of a steel is determined by the heat treatment of the blade.
What is optimal hardness?
Optimum hardness is a balance between toughness and edge retention. Steel with a high number on the Rockwell scale will have higher edge retention but lower toughness. Likewise, steel with a lower Rockwell Hardness rating will not hold its edge for as long, but will be tougher.
What does a lower Rockwell number mean?
A lower Rockwell number means that the steel is softer, relatively speaking, while a higher number indicates a harder steel. Sometimes you'll see Rockwell hardness expressed as a single value, like "59 RC," and other times as a range, like "58-60 HRC.". A steel's final hardness is established by the knifemaker during the heat-treating process.
Which is better, hard or soft knife steel?
Generally, relatively soft knife steels (lower Rockwell numbers) are easier to sharpen but don't hold an edge as long, and a harder steel (higher Rockwell) is more resistant to wear, taking more work to achieve an edge but holding it longer.
Is it important to get the hardness right for a knife?
For the knifemaker, yes -- getting the hardness "right" is a crucial part of crafting a knife that performs as designed. Still, it's only one piece of the puzzle. Other factors -- the type of steel, blade geometry and the knife's intended purpose, to name just a few -- are important, too.
What is the Rockwell C scale?
To accurately express metal hardness, engineers use a standard process called Rockwell testing. In the knife blade manufacturing business, hardness ratings follow a predetermined chart which is commonly called the Rockwell C scale. The higher the number on the RC scale, the harder the steel is. Conversely, the lower the RC scale number is, ...
Who invented the Rockwell Hardness Scale?
History of the Rockwell Hardness Scale. The Rockwell hardness scale gets its name from its inventors, Hugh M. Rockwell and Stanley P. Rockwell. The Rockwell brothers were metallurgists working in a Connecticut ball bearing factory back in the early 1900s.
What hardness is a Rockwell knife blade?
Every industrial machine knife blade has an existing Rockwell hardness. Leading knife blade manufacturers have the experience to recommend and match the right RC hardness for practical uses, which could be cutting anything from paper to plastics.
What scale is used for industrial knife blades?
While industrial knife steel rating usually falls in a number associated with the Rockwell C scale, there are 30 different scales on the patented Rockwell scale chart. C is the most common scale used for knife blade ratings, followed by the B scale.
What is Rockwell hardness?
The most straightforward answer is that Rockwell hardness refers to how resistant a metal object such as a knife blade is to penetration and permanent deformation from another material. It’s a measuring system of non-destructive metallurgical testing that determines how hard and strong steel such as that used in knife-making truly is.
What is the range of a Rockwell scale knife?
Industrial knives will fall somewhere along the Rockwell scale’s C schedule, with a number from as low as 40 to as high as 65. For knife making, the Rockwell procedure involves static indentation testing, which requires two different tests.
What is an indenter in Rockwell?
Often, indenters are a diamond composition or made of high-strength steel, which is to avoid any compression in the inverter head, so all pressure gets evenly applied to the test material. Rockwell testing technicians use two force applications. One is the minor force, which creates the shallow, baseline indentation.