In Current times, Rolls manufacturers usually use high hardness mill rolls in order to obtain high processing efficiency and lower the processing costs. But because of the high hardness, the mill rolls are difficult to machine, so choosing the most suitable insert will become very important.
How to choose insert to machining mill rolls with high hardness?
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Carbide insert, only suit for machining work piece with hardness below HRC45, but the mill rolls hardness will be above HSD90, so the carbide will not affect.
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Ceramic insert, its performance will better then carbide insert, but has high brittleness, so it will easily appear casting defects (such as sand, air-hole).
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CBN insert, its hardness is higher than ceramic insert and carbide insert, even though has brittleness, it has better impact resistance than ceramic insert. But for high hardness mill rolls, it also doesn’t have good effect.
Non-metal adhesive cbn insert which was researched by Halnn, not only has high hardness, excellent wear-resistance, but also solve the problems on machining mill rolls.
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BN-K1 CBN insert: suit for rough machining mill rolls(such as chilled hardened rolls, high Ni-Cr rolls, high chrome iron rolls ).
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BN-S30 CBN insert: suit for machining Centrifugal casting rolls with small working allowance.
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BN-S20 CBN insert: suit for machining bearing steel rolls ,high speed steel rolls ,forged steel rolls and forged steel cold rolls.
Application Case 1:
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BN-K1 Machining Cast Iron Rolls
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Machining Part：Cast iron roll
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Workpiece Hardness: HSD 80
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Machining Materials: High nickel alloy cast iron
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Inserts Grade: BN-K1 RNMN200800
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Cutting Type: Dry Cutting
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Cutting Parameters: ap=4mm,Fr=1mm/r,Vc=55m/min
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Testing Performance
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Inserts Materials
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Feed Rate(mm/r)
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Lifetime/cutting edge
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Failure Mode
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Halnn BN-K1
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1
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3
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Normal wear
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Ceramic Inserts
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0.5
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0.5
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Chipping
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Application Case 2
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BN-S20 Machining Hardened Steel Rolls
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Machining Part：Hardened Steel Roll
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Workpiece Hardness:HSD90
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Machining Materials: High speed steel
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Inserts Grade:BN-S20 RCMX120700
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Cutting Type: Dry Cutting
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Cutting Parameters:Fr=0.2mm/r, Vc=50m/min
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Testing Performance
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Inserts Materials
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Machining time/pcs
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Lifetime/cutting dege
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Effiency improved
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Halnn BN-S20
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12h
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25 grooves
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more tha 6 times
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Carbide alloy Inserts
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2h
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3 grooves
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……
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The cutting parameters of machining mill rolls depending on the rolls materials
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Mill Rolls Materials |
Mill Rolls hardness
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Recommend cutting parameters
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1
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Alloy Cast iron rolls
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HSD60~HSD85
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BN-K1
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V=40~60m/min,ap=2~10mm,f=0.5~1.5mm/r
V=60~90m/min,ap=1mm,f=0.5~1mm/r
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2
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Cast Semi-steel rolls
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V=30~60m/min,ap=1~10mm,f=0.5~1.5mm/r
V=50~80m/min,ap=1mm,f=0.5~1.5mm/r
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3
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High Carbon Semi-steel rolls
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V=35~50m/min,ap=3mm,f=0.5~1.5mm/r
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4
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Chilled hardened cast iron rolls
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V=25~50m/min,ap=1~10mm,f=0.5~1.5mm/r
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5
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Cast high-speed steel rolls
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HSD85~92
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BN-S20
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V=20~45m/min,ap=4mm,f=0.5~1.5mm/r
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6
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WC rolls
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HRA88
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BN-S30
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V=10~15m/min,ap=1mm,f=0.3~0.7mm/r
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7
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Forged steel cold rolls
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HRC65
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BN-S20
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V=90m/min,ap=0.2~0.7mm
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More information on machining mill rolls, please contact with us info@halnntools.com, whatsapp: +8615617635382, skype:info@halnntools.com