Cast iron
ISO K
Machining of cast iron tools
Cast irons, which make up the ISO K group, are Fe-C compositions with a relatively high percentage of Si (1-3). They are short-chipping materials with good chip control in most conditions, though their machinability varies. Added elements such as Cr (chromium), Mo (molybdenum) and V (vanadium) form carbides, which increase strength and hardness but lower machinability. All cast irons contain SiC, which is very abrasive to the cutting edge.
Our coating solutions for cast iron
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 under low lubrication and dry conditions.
Ionbond™ CVD 29
Ionbond™ CVD 29 HSA Plus is exceptionally well-suited for high-volume machining of cast iron and cast steel at medium to high cutting speeds and high temperatures due to the thermo-dynamically stable structure of its ceramic content.
Machinability of cast iron coatings
There are 5 main types of cast iron. Although they all belong to the family of cast irons, the range of properties and applications means that choosing the right tool coating – something the Ionbond engineers would be happy to discuss with you – is of particular importance.
Easy to machine:
Gray Cast Iron (GCI)
Malleable Cast Iron (MCI)
More difficult to machine:
Nodular Cast Iron (NCI)
Compacted Graphite Iron (CGI)
Austempered Ductile Iron (ADI)
- The specific cutting force of cast irons falls between 790 and 1,350 N/mm². Machining at higher speeds, especially of cast irons with sand inclusions, creates abrasive wear.
- NCI, CGI and ADI require extra attention, compared to normal GCI, due to the different mechanical properties and the presence of graphite in the matrix.
- Cast irons are traditionally machined dry, but can also be used in wet conditions, mainly to keep the contamination of dust from carbon and iron to a minimum. There are also grades available that suit applications with coolant supply.
Application examples
Dry continuous turning of a gray cast iron
For an OEM customer looking to machine gray cast iron (GG250) with CNMG 120408 inserts, we are looking for the best coating. The dry continuous turning process has a cutting speed of 400 m per minute, a feed of 0.35 mm per revolution and an axial depth of 2.0 mm. The main issue with gray cast iron is its low impact strength, leading to brittle behavior and abrasive wear. In most other respects, machinability is very good.
Drilling of compacted graphite iron
CGI is a material that can meet the increasing demands for high strength and reduced weight while still retaining reasonable machinability.
Get in touch
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
Dr. Kalpak Shaha
Global Segment Manager Cutting Tools
Dr. Kalpak Shaha
Global Segment Manager Cutting Tools