20 steel is used in construction; machine-building; boiler and tank production; and heating elements of various specifications. High-grade unalloyed structural 20 steel in the form of flat and rolled products is used in preparing parts for weld-fabricated structures, pipelines, accumulators, bearing inserts, slings and other products. Thermo-chemical treatment (cementation, nitriding, nitrocarburising etc.) gives the axles, gears, worm screws, friction discs, shafts, spindles, bolts, cogs, pins and other steel components a strong surface hardness and durability, despite a low core strength.