4140 Q&T is a steel in the family of SAE steel grades, as specified by the Society of Automotive Engineers (SAE). Alloying elements include chromium and molybdenum, and as a result these materials are often informally referred to as chromoly steel (common variant stylings include chrome-moly, CrMo, CRMO, CR-MOLY, and similar). They have an excellent strength to weight ratio and are considerably stronger and harder than standard 1020 steel, but are not easily welded (need pre and post weld thermal treatment to avoid cold cracking). While these grades of steel do contain chromium, it is not in great enough quantities to provide the corrosion resistance found in stainless steel. The Quenching process hardens the steel, while the Tempering process restores some of the ductility and removes some of the brittleness acquired during heat treating.
This material is TG&P which is Turned, Ground and Polished for a very tight diameter tolerance.
The physical properties of 4140 Q&T greatly depend on the tempering processes that have been done to the material. If you need to meet specific physical properties for your application, please contact an Alro Sales Representative to make sure this material will meet your needs.
Typical uses for 4140 include: