H-groups in Seco Material Groups (SMG) 03:24

Since many years, Seco Tools have divided many of the common workpiece materials in to specific groups based on the material type. These major groups were then divided into subgroups which used to be based on the difficulty to machine. But a couple of years ago it went through a huge makeover and all the subgroups were separated based on their type of material. This was done to improve the logic in the split between the material groups. During this work, a number of new major groups were also added.

The major groups are now:

• Steels, ferritic and martensitic stainless steels – P
• 10 subgroups
• Hard materials – H 
• 8 subgroups 
• Austenitic and duplex stainless steels – M 
• 5 subgroups
• Cast irons – K 
• 7 subgroups
• Non-ferrous metals – N
• 4 subgroups
• Superalloys and titanium – S
• 6 subgroups 
• Other difficult materials – Various
• 6 subgroups
• Polymers and composites – Tx
• 8 subgroups
• Graphite – GR 
• 1 subgroup 

This means that the materials in their un-hardened state can be found in the sub-P-groups, but after hardening they will be found in the corresponding sub-H-group. The cutting data recommendations will also change due to this and will be fully reflected in MyPages in both Suggest and Product Search.

For hard turning applications, the major groups are the H-groups where every group has a reference material with reference hardness, as you can see in the table below. The H-groups H3-H12 corresponds to at least one of the P-groups. H3 corresponds to P2 and P3, H5 corresponds to P4 and P5 and so on. H11 corresponds only to P11 and H12 corresponds only to P12.

This means that most of the common steels that are hardenable or considered to be hard and abrasive are found in both P- and H-groups. However, the manganese steels and hard irons are only found in the H-groups H21 and H31 since they do not have a purely soft state.

For more information, please contact your local Seco representative, or our Advanced material (PCBN/PCD/CERAMIC) team.

Author: Stefan G Larsson Fritz Product Specialist SECOMAX PCBN/PCD/CERAMIC SECO TOOLS AB 737 82 Fagersta, Sweden Office +4622340572 Mobile +46761367807 email:stefan.g.larsson@secotools.com