Steel for a hot-formed divisible part, characterised in that its composition comprises, expressed in percent by weight: - 0.15% ≤ C ≤ 0.40%; preferably 0.20% ≤ C ≤ 0.35%; - 0.60% ≤ Mn ≤ 1.80%; preferably 0.80% ≤ Mn ≤ 1.60%; - traces ≤ Cr ≤ 1.60%; - traces ≤ Mo ≤ 0.40%; - traces ≤ Ni ≤ 1.50%; preferably traces ≤ Ni ≤ 1.0%; more preferably traces ≤ Ni ≤ 0.60%; - traces ≤ Cu ≤ 0.80%; - 0.02% ≤ V ≤ 0.70%; - traces ≤ Nb ≤ 0.08%; - traces ≤ Si ≤ 1.20%; preferably traces ≤ Si ≤ 0.60%; - traces ≤ Al ≤ 0.10%; - traces ≤ B ≤ 0.010%; - traces ≤ Ti ≤ 0.10%; - traces ≤ S ≤ 0.15%; preferably 0.005% ≤ S ≤ 0.15%; - traces ≤ P ≤ 0.10%; - traces ≤ Ca ≤ 0.010%; - traces ≤ Te ≤ 0.030%; - traces ≤ Se ≤ 0.050%; - traces ≤ Bi ≤ 0.10%; - traces ≤ Pb ≤ 0.20%; - traces ≤ N ≤ 0.025%; - traces ≤ O ≤ 0.008%; the remainder being iron and impurities associated with the production process; and for which the following relationships are satisfied: * V' = V% + 2 Nb% + Cu%/5 ≥ 0.18%; * Bs = 830 - 270C% - 90Mn% - 37Ni% - 70Cr% - 83Mo% - 50Cu% - 100V% ≤ Bs lim, where Bs lim is calculated as follows: Bs lim = 530 + 330 (V' - 0.18) if 530 + 330 (V' - 0.18) is less than 600; Bs lim = 600 if 530 + 330 (V' - 0.18) is greater than or equal to 600; and in that its microstructure comprises at least 60% of a mixture of bainitic ferrite and of carbides or residual austenite, the remainder of the microstructure comprising not more than 40% martensite and/or proeutectoid ferrite and/or pearlite, the presence of proeutectoid ferrite and/or pearlite being limited to not more than 10%. - 0.15% ≤ C ≤ 0.40%; preferably 0.20% ≤ C ≤ 0.35%; - 0.60% ≤ Mn ≤ 1.80%; preferably 0.80% ≤ Mn ≤ 1.60%; - traces ≤ Cr ≤ 1.60%; - traces ≤ Mo ≤ 0.40%; - traces ≤ Ni ≤ 1.50%; preferably traces ≤ Ni ≤ 1.0%; more preferably traces ≤ Ni ≤ 0.60%; - traces ≤ Cu ≤ 0.80%; - 0.02% ≤ V ≤ 0.70%; - traces ≤ Nb ≤ 0.08%; - traces ≤ Si ≤ 1.20%; preferably traces ≤ Si ≤ 0.60%; - traces ≤ Al ≤ 0.10%; - traces ≤ B ≤ 0.010%; - traces ≤ Ti ≤ 0.10%; - traces ≤ S ≤ 0.15%; preferably 0.005% ≤ S ≤ 0.15%; - traces ≤ P ≤ 0.10%; - traces ≤ Ca ≤ 0.010%; - traces ≤ Te ≤ 0.030%; - traces ≤ Se ≤ 0.050%; - traces ≤ Bi ≤ 0.10%; - traces ≤ Pb ≤ 0.20%; - traces ≤ N ≤ 0.025%; - traces ≤ O ≤ 0.008%; the remainder being iron and impurities associated with the production process; and for which the following relationships are satisfied: * V' = V% + 2 Nb% + Cu%/5 ≥ 0.18%; * Bs = 830 - 270C% - 90Mn% - 37Ni% - 70Cr% - 83Mo% - 50Cu% - 100V% ≤ Bs lim, where Bs lim is calculated as follows: Bs lim = 530 + 330 (V' - 0.18) if 530 + 330 (V' - 0.18) is less than 600; Bs lim = 600 if 530 + 330 (V' - 0.18) is greater than or equal to 600; and in that its microstructure comprises at least 60% of a mixture of bainitic ferrite and of carbides or residual austenite, the remainder of the microstructure comprising not more than 40% martensite and/or proeutectoid ferrite and/or pearlite, the presence of proeutectoid ferrite and/or pearlite being limited to not more than 10%. * V' = V% + 2 Nb% + Cu%/5 ≥ 0.18%; * Bs = 830 - 270C% - 90Mn% - 37Ni% - 70Cr% - 83Mo% - 50Cu% - 100V% ≤ Bs lim, where Bs lim is calculated as follows: Bs lim = 530 + 330 (V' - 0.18) if 530 + 330 (V' - 0.18) is less than 600; Bs lim = 600 if 530 + 330 (V' - 0.18) is greater than or equal to 600; and in that its microstructure comprises at least 60% of a mixture of bainitic ferrite and of carbides or residual austenite, the remainder of the microstructure comprising not more than 40% martensite and/or proeutectoid ferrite and/or pearlite, the presence of proeutectoid ferrite and/or pearlite being limited to not more than 10%. Bs lim = 530 + 330 (V' - 0.18) if 530 + 330 (V' - 0.18) is less than 600; Bs lim = 600 if 530 + 330 (V' - 0.18) is greater than or equal to 600;