A martensitic machining bar with enhanced machinability due to the addition of Sulphur and Phosphorous.
Grade 416/1.4005 has the best machinability of all stainless steel grades, around 85% of that of a free machining carbon steel. This improved machinability is achieved by the addition of sulphur in the chemical composition. This forms manganese sulphide inclusions, and this addition of sulphur also reduces the corrosion resistance, weldability and formability to lower than that of its non-free machining equivalent, 410.
416 can be used both in the unhardened and hardened & highly tempered condition due to its low cost and being easily machinable. Martensitic stainless steels are developed for high hardness, which can sometimes compromise other properties to some degree.
Fabrication must be by methods that allow for poor weldability and usually allow for a final harden and temper heat treatment. Corrosion resistance is lower than the common austenitic grades and their useful operating temperature range is limited by their loss of ductility at sub-zero temperatures and loss of strength by over-tempering at elevated temperatures
Automatic screw machined parts
Washing machine components
Bolts and nuts
|Chromium (Cr)||12.00 – 14.00|
|Manganese (Mn)||0.0 – 1.50|
|Silicon (Si)||0.0 – 1.00|
|Molybdenum (Mo)||0.0 – 0.60|
|Sulphur (S)||0.15 – 0.35|
|Carbon (C)||0.06 – 0.15|
|Phosphorous (P)||0.0 – 0.04|
|Proof Stress||450 Min MPa|
|Tensile Strength||650 – 750 MPa|
Mechanical properties vary greatly according to the heat treatment that the material has undergone. Material in the annealed condition shall have a hardness reading of 220 HB Max and a Tensile test reading of 730 MPA Max
416 has lower corrosion resistance than other common austenitic stainless steel grades. It is resistant to dry atmospheres, fresh water and milk acids and alkalies but less so than its equivalent non-free-machining grades. It is less corrosion resistant than 17% chromium ferritic alloys such as grade 430. The high sulphur content in 416 makes it unsuitable for use in marine environments or environments exposed to chloride. Max corrosion resistance can be achieved in the hardened condition with a smooth surface finish.
Grade 416 has excellent machinability, with it being the highest of any commonly available stainless steel grades. The best machinability is in the sub-critical annealed condition.