Want to know more about ISO material groups?
Discover all the different materials and their specificities, the main challenges for each of them and how to overcome these challenges.The machinability of workpiece materials influences strongly the profitability of the machining industry.
Making the wrong choice of tools and cutting conditions during a cost estimation can lead to costs gaps and potential financial losses for your company.
This is why Seco wants to provide support from the price quote to the delivery of the workpieces and help you achieve maximum productivity and profitability.
We aim to give you an overview to know better the iso materials and prepare yourself for the constraints encountered during machining, in order to put the odds in your favor and overcome your machining challenges.
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ISO P – Steel is a wide range of material groups, from unalloyed to high-alloyed material, including ferritic and martensitic stainless steels. The machinability is good, but we can observe several variations in regard to the material hardness and some mechanical properties.
ISO M – Stainless steels are materials alloyed with a minimum of 12% chromium. Other alloys may include nickel and molybdenum. Different conditions, such as ferritic, martensitic, austenitic and austenitic-ferritic (duplex), create a large range of materials. A commonality among all these materials is that the cutting edges are exposed to a great deal of heat, notch wear and built-up edge.
ISO K – Cast iron, unlike steel, is a short-chipping type of material. Gray cast irons (GCI) and malleable cast irons (MCI) are quite easy to machine, while nodular cast irons (NCI), compact cast irons (CGI) and austempered cast irons (ADI) are more difficult. All cast irons contain SiC, which is very abrasive to the cutting edge.
ISO N – Non-ferrous metals are softer metals, such as aluminum, copper, brass, etc. Aluminum with a Si-content of 13% is very abrasive. Generally, high cutting speeds and long tool life can be expected for tools with sharp edges.
ISO S – Heat resistant super alloys include a great number of high-alloyed iron-, nickel-, cobalt- and titanium-based materials. They are sticky, create built-up edge, harden during working (work hardening), and generate heat. They are very similar to the ISO M materials but are much more difficult to cut and reduce the tool life of the insert edges.
ISO H – This group includes steels with a hardness between 45–65 HRC, and also chilled cast iron around 400–600 HB. The hardness makes them difficult to machine. The materials generate heat during cutting and are very abrasive for the cutting edge.
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Seco Material Group, or SMG, is a workpiece material classification system that helps users quickly and easily identify the most reliable tool and cutting data for a particular workpiece material based on color.
In 1990, Seco developed the color-coding system, Secolor, for ISO material groups and set the benchmark as the first company in the cutting tool industry to classify materials in this simple yet logical way. Later Secolor evolved into the SMG system.

You can find the Secolor matrix in different places to ease your life:
- On the product packaging to show possible application ranges
- In the Machining Navigator/ catalogue
- When using Suggest or the Seco Assistant to guide your way
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