Two laboratory heats of low-Carbon low-alloy steels, one with boron and chromium additions and other with boron, chromium and molybdenum additions were made and cast into pencil ingots. These ingots were hot-rolled to 2 mm sheets suitable for press hardening application in an experimental rolling mill. A detailed study was made on the effect of various alloying elements on the microstructure and mechanical properties of these steels. A significantly higher hardness (~496 VHN), yield strength (~1137 MPa) and ultimate tensile strength (~1673 MPa) with comparable elongation (~6%) could be achieved in the as rolled and water-quenched Mo-Cr-B steel in comparison to Cr-B steel under similar processing condition. Moreover, a reduction of critical cooling rate by10oC/s was observed in this steel to obtain fully martensitic structure. The combined addition of boron, chromium and molybdenum was found to be more effective than that of boron and chromium in enhancing the microstructure and mechanical properties of boron-added steels. Additionally, a few hot compression tests were carried out to simulate the press hardening process of these experimental steels. It was found that one of the press hardening process parameters, viz., prior strain had a greater impact on the transformation behaviour of Cr-B and Mo-Cr-B steels during cooling. © 2018, Technical Faculty in Bor. Dva laboratorijska uzorka niskolegiranog čelika sa malim sadržajem ugljenika, prvi sa dodatkom bora i hroma, a drugi sa dodatkom bora, hroma i molbidena, napravljena su i izlivena u četvrtasti ingot (odlivak). Ovi ingoti su valjani u toplom stanju dok nisu dobijeni limovi debljine 2mm koji su pogodni za postupke vrućeg presovanja u eksperimentalnim valjaonicama. Detaljno su ispitani uticaji različitih legirajucih elemenata na mikrostrukturu i mehanicke osobine ovih uzoraka čelika. Značajno viša tvrdoća (~496 VHN), napon na granici tečenja (~1137 MPa) i zatezna čvrstoća (~1673 MPa) sa relativnim izduženjem (~6%) mogu se postici kod Mo-Cr-B čelika dobijenog valjanjem na taj način i kaljenim u vodi u poredenju sa Cr-B čelikom pod sličnim uslovima tokom postupka. Osim toga, uočeno je i smanjenje kritične brzine hladenja za 100C/s kod ovog uzorka za dobijanje potpune strukture martenzita. Dodavanje kombinacije bora, hroma i molibdena je efektnije nego dodavanje samo bora i hroma za mikrostrukturu i mehaničke osobine čelika sa dodatkom bora. Pored toga, izvedeno je i nekoliko ispitivanja materijala na pritisak u toplom stanju da bi se simulirao postupak kaljenja pod presom ovog eksperimentalnog čelika. Došlo se do zaključka da je jedan od parametara ovog postupka, prethodno istezanje, imao veci uticaj na transformaciju Cr-b i Mo-Cr-B čelika tokom hladenja. © 2018, Technical Faculty in Bor.