The choice of CD vs T&P (cold drawn versus turned & polished)
Not all cold finished steel is the same. While cold drawn and turned & polished steel bars have similarities, they are actually different in many ways. Depending on the final end use of the steel, one product may vastly outperform the other. Cold drawn steel will always machine better and have better mechanical properties. Turned & polished will always be free of surface defects and decarb. If a machinist is familiar and used to processing cold drawn steel and suddenly switches to T&P, they will notice reduced tool life and production output.
Both CD and T&P fall under the ASTM A108 cold finished specification (and remember ASTM A108 does not call out mechanical properties or machinability, so you can receive an incorrect cold finished product if not ordered specifically as CD or T&P). It’s important to understand the differences before making a choice, and we’ve provided a data sheet below that compares the distinct features of both products: