Do you know that Ductile iron is often the preferred material for hydraulic manifolds? In any custom-machined manifold and a block of steel, the choice of material has been ductile iron for quite a few decades. Ductile Iron is also an excellent alternative to carbon steel. Industry experts describe cast iron as hard, brittle and not easily machinable. Cast Iron covers a broad range of materials having tensile strength between 10,000 to 250,000 psi, based on which it is cast and treated with heat.

It can be further seen that ductile iron is a continuous-cast material built with maximum strength in comparison to that of free-machining steels and plain carbon. This said ductile iron is more machinable than steel. It can save on costs substantially by extending tool life and minimizing machining time. In addition to better machinability, ductile iron, in effect, can produce fewer burrs when it comes to drilling. Consequently, it adds to the cost of a manifold. Nevertheless, blur removal is easily achievable with ductile iron, which further leads to increased cost savings, particularly with manifolds.

In comparison with hot-rolled steels, continuous cast ductile iron does not need ultrasonic testing prior to machining. Though hot-rolled steel has sulphur and other agents enhancing machinability, inclusions, cavities or discontinuities can be produced by these agents, thereby turning a highly machined manifold into scrap. Usually ductile iron does not need these machinability agents, manifold manufacturers normally can do away with the cost of ultrasonic testing. 

However, steel is not replaceable at all times such as welding something to a machined manifold. Steel has improved weldability, and offsets any extra cost of welding even more than the cost advantage of machinability it provides. Another important advantage of ductile iron is availability. Size dictates whether we need to use ductile iron or steel. For a larger manifold (than a specific size limit), we have to settle with steel, and perhaps we may continue increasing its cross-sectional size.