1. Types and processing characteristics of cast iron

Cast iron can be classified according to its classification; Grey cast iron, white cast iron, malleable cast iron, nodular cast iron, vermicular cast iron, alloy cast iron and so on. Among them gray cast iron is widely used in the automobile industry, and the automobile industry has big demand of CNC cutting tools, so the processing plant often has the demand of gray cast iron.

2. What tools are used to process common cast iron

This article refers to the common cast iron is gray cast iron, ductile cast iron and austenitic cast iron, the processing performance of gray cast iron is better, such as the use of alumina coating carbide milling cutter, mostly competent for the cutting of gray cast iron. Because the graphite content of nodular cast iron affects its machining performance, the economical coating alloy milling cutter with solid carbide bar can be generally used. 

Ordinary cast iron machining tool, economical tungsten steel milling cutter can be competent. Secondly, high speed steel cutter containing cobalt can be used.

3. What cutting tools are used for refractory cast iron

Here only examples of chilled cast iron, chilled cast iron is a kind of anti-wear cast iron, it is in casting cast iron through accelerating the surface cooling to wait a little, so that the surface layer to obtain white cast iron structure, formed a high hardness, high wear resistance characteristics. Chilled cast iron can be divided into ordinary chilled cast iron, Ni-Cr chilled cast iron, high chromium white cast iron and chromium vanadium white cast iron, etc.

1)   Processing characteristics of chilled cast iron

The hardness of chilled cast iron is very high, brittleness is very large, the unit cutting force is also very large, and its chip is broken shape, because the tip and the cutting contact is short, resulting in cutting force and cutting heat concentrated near the cutting edge, easy to make the tool wear and damage. The machining of chilled cast iron is mostly blank, the machining allowance is large and uneven, which increases the difficulty of cast iron processing. Of course, at present there are good solution for the cast iron machining tool, cast iron milling cutter, etc.

2)   Choice of cutting tools for chilled cast iron

It is best to choose the tool material with high hardness, good wear resistance and certain strength for processing chilled cast iron. It is generally coated with fine grain or ultra-fine grain YG class hard alloy or alumina ceramic tools. Generally, it is coated with fine grain or ultra-fine grain YG class hard alloy or alumina ceramic tool. 

3)    Cutting parameters of chilled cast iron milling cutter

Carbide cutting tools: Low speed and large feed. About V=9m/min, the feed is generally selected according to the main deflection Angle and the back draft. Cast iron is chosen 0.5mm/r for rough machining and 0.1-0.4mm /r for finishing machining.

Ceramic cutting tools: High speed milling is generally selected. Coarse and semi-finished cast iron V=50~80m/min, and fine processing V=80~120m/min.

Cast iron machining tools, such as knife grain, can be coarse, semi - fine and finishing. If you do not know cast iron with what milling cutter, machining cast iron milling cutter is of course the choice of YG class carbide tool

Moresuperhard can provide you CBN tools for machining cast iron:

PCBN tools are mainly used for processing difficult materials and high hardness materials (>HRC35), such as tool steel, high speed steel, hardened steel, austenitic soft iron, etc. Wear resistant materials such as grey cast iron, sintered iron, etc. Refractory materials such as surface coating material, surface hardening alloy, nodular cast iron, etc., and PCBN tool can replace the traditional grinding process, the precision of processing can be up to IT5-IT6, the surface roughness can reach Ra0.8~0.2 m, can achieve the precision of grinding. 

1. Processing gray cast iron
High speed cutting gray cast iron material is one of the typical applications of PCBN tool. When PCBN tool high speed cutting gray cast iron, the tool life can reach 20-30 times of ceramic tool. For PCBN cutting tools of different grades, the higher the content of CBN, the higher the hardness, wear resistance and thermal conductivity of PCBN cutting tools. When the ferrite content lower than 10% in grey cast iron material, more suitable for PCBN cutting tool machining, at this moment of PCBN cutting tool life is longer, because when ferrite too much, when will with boron element of CBN cutting by biochemical reactions, thus make PCBN cutting tools of chemical wear increases, lead to lower the service life of cutting tools. In machining gray cast iron, need extra attention to one aspect is timeliness, namely casting workpiece after using PCBN cutting tool machining time, this is because the gray cast iron casting, will produce large amounts of oxygen and nitrogen, which will be harmful to durability of PCBN cutting tool, so take some time for oxygen and nitrogen volatilization, to ensure the normal use of the cutting tool life, general aging days for 10 days.

2.Machining hardened steel
The hardened steel is a typical hard to be machined and wear resistant material. Grinding has always been used to finish the finishing of hardened steel parts before. When using PCBN tool to process the hardened steel, the processing efficiency is faster than grinding, which is more suitable for cutting parts of different shapes and more flexible than grinding. Because PCBN cutting tools often use dry cutting, can also avoid the waste cutting fluid pollution and save energy. And the surface quality of machining and grinding, or even higher than grinding. PCBN tool in the process of high speed cutting hardening steel, the high heat produced by the workpiece material cutting area constantly softening, so as to carry out cutting, compared with the carbide tool, the efficiency is greatly improved, and can improve the surface roughness of the workpiece, improve the machining accuracy.

3. Hard to process materials
Relatively speaking, PCBN tool in the processing of ductile or vermicular cast iron applications and advantages are relatively small. PCBN tool is easy to produce serious chemical wear during the processing of ductile or vermicular cast iron, and the tool life is reduced. Therefore, when PCBN tools have to be used to ensure the dimensional accuracy and shape and position tolerance of parts, they are usually coated to protect PCBN tools and increase their durability. In addition to the typical applications mentioned above, PCBN tools can also be used for cutting nickel base superalloys, surface hardening alloys, hard alloys, ceramics, powder metallurgy and other materials. It has good advantages in machining efficiency, workpiece dimension precision, surface roughness and tool durability, and has been widely used.