Introducing the New AC4000K Series for Cast Iron Turning

Sumitomo has developed the new "AC4000K" series, to be launched in May 2017, for improved stability and longer tool life in the turning of gray and ductile cast iron.


Cast iron can be used to produce complex machine components at relatively low cost, as its strength can be increased by adding additives to change its metal structure. From such features, automotive structural parts with complicated shapes, such as sliding parts*1 found in disc brakes that require lubrication and vibration damping properties or gear casing where strength is required, can be made from cast iron.

Gray cast iron*2 is a highly workable material with low impact strength and high thermal conductivity, generally resulting in a long tool life. However in recent years, with the increased demand for high efficiency machining, suppressing noticeable flank wear under such conditions has become a task for improving tool life. On the other hand, ductile cast iron*3, a material with high tensile strength, also poses a problem to cutting tools as it causes the cutting edge to heat up easily and also easy work adhesion, resulting in inconsistent tool life.

In response to these challenges, Sumitomo has developed the new "AC4000K" series for cast iron turning. Although the retail price is set at the same level as existing products; this new series will contribute greatly to lowering overall production costs by providing more stable tool life, thus reducing tool usage and frequency of tool replacement, and higher efficiency, resulting in shorter machining time.


Thick coating CVD*4 grade with excellent thermal resistance. Utilizing a high-strength, grain-orientation controlled alumina layer and new surface treatment to provide exceptional wear resistance while suppressing chipping and tool fracture. In addition, higher adhesion strength between the CVD layer and substrate provide twice as much resistance against peeling than conventional. This grade is capable of withstanding high cutting speeds of up to Vc=700m/min in the machining of gray cast iron.

A general purpose CVD grade with outstanding stability. Adopts the same newly developed high coating adhesion technology similar to AC4010K, giving it improved resistance to coating peel-off by work adhesion. When used in machining where the coating layer is likely to peel-off, it's improved coating adhesion gives cutting edges twice the stability of conventional coating layers. The first recommendation grade for cast iron turning.


Negative type 392 items
Positive type 96 items
Total 488 items

Sales Plan

¥100 million in the first year, ¥300 million a year after 3 years (AC4010K and AC4015K combined)


Set the same as for our existing products

Standard type:CNMG120408N-GZ ¥770 (¥832 with tax)

*1Sliding parts:
Parts within a machinery that rub against each other.

*2Gray cast iron:
Cast iron refers to an alloy whose base components are primarily carbon (C) and silicon (Si), where the carbon content is 2.1% or higher. Gray cast iron is a type of cast iron consisting of carbon that is more graphite than cementite, resulting in a gray-colored fracture surface.

*3Ductile cast iron:
A type of cast iron that has slightly higher carbon and silicon contents than gray cast iron; its graphite structure is spheroidized by adding magnesium and cerium.

*4CVD (Chemical Vapor Deposition):
A method for forming a coating layer through vapor deposition, on the surface of the substrate material which has been heated within a reaction chamber. Raw material gases containing components of the target coating are fed into the chamber where they will chemically react and form the coating.