Look at today's cast iron machining

Everyone knows that choosing the right metal and cutting tool combination can have a huge impact on part costs.

Imagine a metal that has the strength of a rebar, but can be processed into a finished product at twice the speed, and the tool wears less. Its weight is reduced by 10%, it can be heat treated without carburizing, and it will not deform. It has shock-absorbing properties to make the gear set quieter, and the cost per pound is about the same as the cost of reinforcing steel. What is it? If you haven't guessed, the high-tech metal mentioned above is today's cast iron.

Today, cast iron is more advanced than it was 20 years ago. They are lighter, stronger and more affordable. In fact, cast iron can replace steel because you are under pressure to keep costs down, and you can strike a good balance between mechanical properties such as durability and workability. However, there are some variables and challenges when trying to determine the right tool for your cast iron machining operation.

First, the harder the material, the more difficult it is to process. The types and quantities of pig iron and slitting steel in the base material, the silicon inoculant used to nucleate graphite, and the alloy used to stabilize pearlite are to a certain extent This affects workability. In the continuous casting process, the thickness and concentricity of the solidified edges of the bar are the decisive factors, and it is necessary to ensure that all processes are in a controlled state so that the tiny hard spots generated during the rapid cooling process can be dissolved. Proper control of these factors at the foundry allows continuous cast iron rod users to increase turning speeds from 600 sfm to 1200 sfm without losing tool life.

Secondly, it is important to understand the different types of cast iron and realize that each cast iron has different levels of strength, cost and workability. For each type, there are several grades with different mechanical properties. You must also consider the complexity of cast iron metallurgy. The casting process produces microstructures whose properties vary between the surface of the part and its internal body. The quality of cast iron also varies from one foundry to another.

Here are some types of modern cast iron to choose from:

• In the most common and cheapest type of gray cast iron of all types, the inclusion of carbides in the form of flake graphite particles makes them excellent vibration damping, making them ideal for engine components. Compared to other types, it also has the highest processability.

• Compared with gray cast iron, compacted graphite iron is also called compacted graphite iron, which has higher strength and lighter weight. Because vermicular graphite cast iron is suitable for components that are subject to mechanical and thermal stress, it is used more by car manufacturers in the production of cylinder heads and brake parts.

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Silicon alloy ferritic ductile iron is ideal for the production of wheels and axles. Due to its high machinability and excellent mechanical properties, the material is becoming increasingly popular in the automotive industry.

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Ductile iron, composed of spherical spherical graphite particles in ferrite and / or pearlite matrix, has high ductility, good fatigue strength, excellent abrasion resistance and high elastic modulus, so it has become the material of transmission housing Select as well as wheel suspension parts for the automotive and heavy equipment industries.

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Austenitic ductile iron has high strength, high fatigue strength, good wear resistance and high elongation at break, so it is a very competitive material compared to many cast steels and forged steels. Due to its high strength and elasticity, austenitic ductile iron has the lowest workability compared to other types of cast irons mentioned here.

Although one type of tool can successfully cut all different types of cast iron, this does not mean that it can efficiently process each type of workpiece shape. You have to think about the surface you want to cut and then ask yourself: is the shape square or rectangular? Is the wall thickness thin or thick, weak or stable? And, how safe is the work clamping?

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You have to consider your machine. When machining cast iron materials, there are higher dynamic loads, so your machine must be very strong and must have high power and stability-all of which puts the machine under pressure. However, in these cases, a negative milling cutter with a positive rake angle can help reduce the power requirements of the machine and reduce the force on the machine's spindle.

Finally, there are many variables to consider, and if you want to increase the productivity and predictability of your cast iron machining job, the best option for you is to work closely with your cutting tool supplier.