Steel grade 16MnCrS5

Steel grades 16MnCrS5 and 20MnCrS5 are carburizing alloy steels with the addition of sulfur to improve machinability. They are modified popular 16MnCr5 and 20MnCr5 steels, widely used in the engineering and automotive industries. Thanks to the carburizing and quenching process, these steels achieve a hard wear-resistant surface and a ductile, tough core, making them ideal for the manufacture of parts operating under high surface and dynamic loads. The addition of sulfur improves the machinability of the material, which has a beneficial effect on the machining process in the mass production of parts with complex shapes. Machining is carried out on automatic lathes and other cutting machines.

The carburizing process is a key step in the heat treatment of these steels. It involves saturating the surface layer of the steel into carbon while annealing the component over a specified period of time in a medium containing atomic carbon. Carburizing takes place at a temperature of about 880 - 980 °C. After carburizing, the steel is hardened and tempered, resulting in a very hard and wear-resistant surface while maintaining a ductile core. The depth of hardening can be controlled by the duration of carburizing, allowing the properties of the steel to be tailored to specific applications.

Heat treatment of 16MnCrS5 and 20MnCrS5 steels involves quenching in oil or water at 880-920°C (for the carburized layer at 780-820°C), which increases their surface hardness. Another operation is tempering, which is carried out at 150-200°C to reduce stresses and improve fracture toughness.

A very important factor in determining the mechanical properties of a steel is its chemical composition. According to melt analysis, the chemical composition of 11SMn30 steel should be in accordance with the values given in the table below.

Designation		C in % max.	Mn % max.	Si % max.	Cr % max.	P % max.	S % max.
16MnCrS5	1.7139	0,14-0,19	1,00-1,30	0,40	0,80-1,10	0,025	0,02-0,04

Steel	Mechanical properties
Steel mark	Rp0,2 [MPa]	Rm [MPa]	Hardness HB	Elongation [%]
16MnCrS5	400-450	600-780	180-250	10-15

16MnCrS5 and 20MnCrS5 steels are very good materials for components that require a combination of a hard wear-resistant surface and a ductile, strong core. Typical applications include:

Gears
Shafts and axles
Transmission components: gearboxes, differentials
Pins and bushings
Precision machine parts: Series production where high quality machining is required.