What distinguishes cast iron threaded T's from malleable iron threaded T's?

The distinguishing factor between cast iron threaded T's and malleable iron threaded T's is primarily related to the malleability of the material. Cast iron is known for its brittleness and rigidity, which makes it less flexible and more prone to breaking under stress. In contrast, malleable iron is treated to enhance its ductility, allowing it to bend or deform slightly without breaking. This characteristic is particularly important in applications where some amount of movement or adjustment is necessary, such as in piping systems.

Malleable iron threaded T's can withstand more stress and strain without failure compared to cast iron counterparts. This difference in malleability makes malleable iron fittings more suitable for many applications, especially in environments where thermal expansion, contraction, and vibrations may occur.

While other choices like diameter of pipe connections, thread pattern, and inlet band comparison can vary between different types of fittings, they do not fundamentally define or distinguish the materials themselves in the context of their use and properties. The notable difference in ductility, or lack thereof, which affects performance and applicability, is what primarily informs the choice between using cast iron or malleable iron threaded T's in piping installations and repairs.