Cutting Tools Hard steel ISO H

Machining of hard steel tools

Materials with high hardness fall under the ISO H group of materials. Their hardness makes them difficult to machine: the materials generate heat during cutting and are very abrasive for the cutting edge. Because of that, hardened steel is not a common work piece material for machining. Finishing is the most common machining operation for these materials. Typically, however, hard part turning falls within the range of 45-68 HRC.

Our hard steel coating solution

Cutting Tools
Hardcut milling cutter

Hardcut™ Plus

Hardcut™ Plus, a TiSiN based multi-layer coating, has been developed for high speed end-milling and gear hobbing of the hardest and toughest materials including exotic nickel and titanium alloys unde…

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Machinability of hard steel coatings

  • The specific cutting force needed for hardened steel is  2,550–4,870 N/mm², which is quite high and also comes with a high power requirement. The operation usually produces fair chip control.
  • The cutting tool material needs to have good resistance to plastic deformation (hot hardness) and good chemical stability (at high temperatures), mechanical strength and resistance to abrasive wear. Cubic boron nitride (CBN) has these characteristics and makes turning possible, instead of grinding.
  • Cemented carbide dominates in milling and drilling applications and is used up to approx. 60 HRC. Mixed or whisker-reinforced ceramic is also used in turning when the workpiece has moderate surface finish demands and the hardness is too high for carbide.
  • Because of the tough conditions involved in machining of ISO H materials, the right coating can prolong the lifetime and improve the performance of the cutting tools involved. Ionbond engineers would be happy to discuss your specific application and guide you towards the most appropriate coating.

Application examples

Cutting Tools coating solutions | Ionbond

Dry milling of HRC die

An OEM customer is looking for the right coating to enhance dry milling of SKD11 tool steel (HRC 60-62) with a square end mill (Ø8 mm). The milling process uses a 4000 rpm tool rotation speed, cutting speed of 100 m per minute, a radial depth of 0.25 mm and an axial depth of 8 mm.

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Cutting Tools coating solutions | Ionbond

Insert milling of hard steel

Finding the right coating for an OEM customer machining 1.2379 steel with an HRC of 62. The cutting speed of the process is 160 m per minute. Cutting length is 141 m. Other process parameters: feed per tooth is 0.25 mm, axial depth is 0.22 mm and radial depth is 0.3 mm.

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Discuss your challenges with Kalpak Shaha

Dr. Kalpak Shaha, Global Segment Manager Cutting Tools, will be glad to support you.

We will get back to you as soon as possible

Kalpak Shaha

Dr. Kalpak Shaha

Global Segment Manager Cutting Tools