4140 Quench & Tempered Stress Relieved
4140 Quench &Tempered -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. 4140 material very suitable for cylinder rod and cylinder barrel
The physical properties of 4140 Quench & Tempered greatly depend on the Heat Treating/Tempering processes that have been done to the material.