Types of steel and their purpose

Steel for carburizing: Machines' elements with a required top layer with high hardness and ductile core. Gears, worms, shafts, bushings, of large dimensions, succumb to very high pressures and loads.

16HG/16MnCr5 STEEL
16HG or 16MnCr5 are steels for carburizing. Products made from those steels are characterized by high resistance. Those types of steel have specific properties – they are characterized by considerable ductility of the core at high surface hardness. 16hHG is mostly used for the production of medium loaded machine elements with small dimensions (up to 30 mm). Therefore, they are primarily: screws, bushings, gears, pins, camshafts and forming plates. Welding the 16HG or 16MnCr5 steels is only possible before carburizing.

18HGT is construction steel, common for carburizing, thanks to its increased alloying. It is characterized by high surface hardness and core strength with uniform tenacity. It is used for the production of small and medium elements, heavily loaded. These are mostly: gears, differential parts, and transmission shafts. When using larger cross-sections, the core properties deteriorate. Welding 18HGT steel is only possible before and after carburizing.


16HG 16MnCr5 1.7131 5115
15HN 17CrNi6-6 1.5918  
17HNM 18CrNiMo7-6 1.6587 4820
20HG 20MnCr5 1.7147 5120
18H2N2 19CrNi8 1.2722  


Steel for toughening: for heavily loaded parts, exposed to impacts, torsion, vibrations: shafts, crankshafts, rotors and discs of steam turbines, spindles, levers, vehicle shafts, connecting rods, pump and press shafts, control parts, rings, etc.

40H/41Cr4 STEEL
40H and 41Cr4 are the chrome steels for toughening and surface quenching.
They form heavily loaded medium-sized parts (up to 40 mm). These are mainly: bushings, axles, crankshafts, gears, piston rods, abrasive discs, instrument bodies, fasteners, surface hardening elements and molds with longer durability. 40H steel is easy to chemically treat, but hard to weld - this process is only possible after preheating. After finishing the preheating, apply heat treatment.

C45 is non-alloy quality steel for quenching and tempering. It is characterized by high durability and ductility. It is used for the production of medium loaded machine and equipment elements, more resistant to abrasion. These are mainly: axles, shafts, spindles, unhardened gears, shafts of electric motors, knives, corkscrews, wheel hubs, rods, rollers, discs, screws, levers, pump rotors. C45 steel is easy to process, but hard to weld. Elements made of it can be surface quenched - then they obtain hardness up to 50 - 60 HRC.

35HGS is construction steel for toughening and surface quenching. It is characterized by high abrasion resistance and high durability. It is used to manufacture heavily loaded components (but after thermal improvement or quenching), which are mainly used in the construction of medium-sized machines. Those are shafts, axles, connecting rods, spindles, levers and semi-axles of trucks and tractors. 35HGS steel is hard to weld, but it is susceptible to mechanical treatment and cutting.

S355I2 is a universal, low-alloy, high-quality construction steel. It is characterized by high strength and tenacity, good processing and fine graining. S355I2 is steel with guaranteed weldability at an increased yield point. It is susceptible to cutting with a gas torch and plasma. It is used for the production of machine parts, engines, and entire machines. From this steel can be created: pressure pipes, bridges, tanks, machine construction elements, etc.


Quality steel of this type is used to manufacture parts with a small cross-section. It is characterized by high strength and toughness.
36CrNiMo6 1.6511 4340
Construction steel for thermal improvement. Most often used for the production of elements exposed to overloads.
34CrNiMo6 1.6582 4337
40H 41Cr4
Chrome steel for heat treatment and quenching. It is hard to weld but easy to mechanical treat.
1.7035 5140
25HM   1.7218 4130
Construction alloy steel for surface quenching and heat treatment.
High-strength steel for hardening and heat treatment. Used for the construction of heavy-duty components such as axles, shafts, etc.
25CrMo4 1.7225 4140


Creep-resisting steel: for work at high temperatures on responsible machine parts, accessories in the construction of steam turbines, rotor shafts, bolts, nuts and for the construction of pressure equipment intended for operation at high temperatures.


Polish Norms EN W.NR AISI
15HM 13CrMo4-5 1.7335 P12
13HMF 13CrMoV9-10 1.7703 P22
21HMF 21CrMoV5-7 1.7709  


Tool steel for hot work: Mold components for pressure casting, tools for extrusion of low melting alloys, matrix inserts, stamping dies, punches, punches, forging dies working under high load, hammer dies of medium size and deep cuts, loaded matrix inserts, tools for extrusion, thread rolling jaws, drawing dies, copper alloy pressing dies, etc.


Polish Norms EN W.NR AISI
NC11 X210Cr12 1.2080 D3
NC11LV X153CrMoV12 1.2379 D2


Carbon and non-alloy steel: Medium load parts, such as axles, crankshafts, eccentric and toothed shafts, spindles, rollers, pump rotors, pistons, levers, wedges, rods, screws, rings, etc. Welded, riveted and joined constructions arise from non-alloy steel bolts, operating at ambient temperature.

Free-machining steel: For machining on automatic cutting machines and high-speed thread cutting machines.


Polish Norms EN W.NR AISI
45 C45 1.1191 1042
St5 S275J2 1.0145  
St3S S235JR 1.0038  
Alloy weldable steel with high resistance. Mostly used for producing construction elements.
S355J2G3 1.0045  
R35 E235N 1.0308  
55 C55 1.1203 1055