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Table 1 shows the averaged machinability rating for
 different cast iron types. Pearlitic grey cast iron, which
 is specified as 100% rating, provides a base
 for comparison.





 Table 1- Machinabilty rating of cast iron (averaged data)
 Material  Condition  ISCAR   Machinability
 Mat. group*  %
 Grey    Ferritic  15  130
 cast iron (GCI)  Pearlitic  16  100
 Nodular    Ferritic-Pearlitic  17  75
 cast iron (NCI)  Pearlitic  18  70
 Malleable   Ferritic  19  115
 cast iron (MCI)  Pearlitic  20  93
 Compacted grathite iron (CGI)  ~17  80
 Austempered   Soft  ~10  80
 ductile iron (ADI)  Hardened  41  35
 Ni-resist austentic CI  90

 Chilled cast iron  HB 400...440  40  50
 Hardened cast iron  HB 550...600  41  25
 * ISCAR material group in accordance with VDI 3323 standard




 Selecting the most suitable cutting tool for machining   every effort to find the most effective solutions for
 cast iron should be based on a detailed study   machining cast iron, taking into account the diversity
 of a cast iron type and its hardness. Cutting tool   of the cast iron world. Among the main consumers of   On a firm basis  which enables a considerable increase in cutting
 application specialists, who are involved in selecting   cast iron are the automotive, die and mold, machine   The previously mentioned difficult-to-cut hard/  speeds. In machining hard cast iron, for instance, the
 right tools, need to be fully accurate when specifying   tool, and heavy industries – all demanding increasingly   high chrome cast iron produces serious barriers for   speeds are 2-5 times higher when compared with
 characteristics of the cast iron that is intended for   efficient products from their cutting tool partners.   machining productivity. A cutting tool experiences high   cemented carbide. ISCAR's high-performance milling
 machining.  In turn, cutting tool manufacturers make
        mechanical and thermal loading. In milling this cast   cutters carrying tangentially clamped inserts with CBN
        iron by cemented carbide tools, for example, a typical   tips are extremely popular in the automotive industry.
        cutting speed is low: 40-50 m/min (130-160 sfm).       For hard turning applications, the company expanded
        Intensive heat generation often forces manufacturers to   the range of CBN tipped ISO-type inserts for both
        apply wet coolant. As a result, the tool operates under   continuous and interrupted cut
        conditions of a heat shock effect, which considerably
        shortens the tool life.                                In ISO K applications (machining grey, nodular and
                                                               malleable cast iron) in medium-duty loading, ceramic
        ISCAR developed the DT7150 grade especially for        tools have demonstrated good results. Peripherally
        this type of operation. DT7150 is a "DO-TEC" carbide   ground tangentially clamped TANGMILL milling
        grade that has a tough substrate and combines          inserts, made from the silicon nitride (Si3N4) grade
        medium-temperature CVD and PVD coating processes.  IS8, ensures increasing cutting speed up to 3 times
        Due to its extremely high wear and chipping resistance,  and provide excellent surface finish. In turning, cutting
        DT7150 provides customers with an effective tool       speeds of up to five times faster can be achieved by
        material for cutting hard cast iron.                   using the CVD-coated silicon nitride inserts, even for
        A fundamental significant change in productivity can   roughing operations.
        be reached with the use of cubic boron nitride (CBN),
 TELLIGENTLY
 18  MACHINING  IN  DUSTRY 4.0                                                                           ISCAR    19
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