FIELD: metallurgy.
SUBSTANCE: invention relates to metallurgy, namely to a solid round-section steel workpiece from martensite stainless steel for a well element. Workpiece has the following chemical composition, wt%: C: 0.020 or less, Si: 1.0 or less, Mn: 1.0 or less, P: 0.03 or less, S: 0.01 or less, Cu: from 0.10 to 2.50, Cr: from 10 to 14, Ni: from 1.5 to 7.0, Mo: from 0.2 to 3.0, Ti: from 0.05 to 0.3, V: 0.01 to 0.10, Nb: 0.1 or less, Al: from 0.001 to 0.1, N: 0.05 or less, B: 0 to 0.005, Ca: 0 to 0.008, Co: 0 to 0.5, the rest is iron and impurities. If content of Mo in the chemical composition of the workpiece, denoted as [amount of Mo] (wt%), and Mo content in the extracts in a position which bisects the line from the workpiece surface to the center in a section perpendicular to the longitudinal direction of the workpiece, denoted as [total amount of Mo in the precipitates in position R/2] (wt%), the following ratio is satisfied: [Amount of Mo]-4×[total amount of Mo in secretions in position R/2]≥1.30, and with content of Mo in discharges in position of cross section center, perpendicular to longitudinal direction of workpiece, denoted as [total amount of Mo in discharge in center position], then the following ratio is satisfied: [Total amount of Mo in the secretions in the center position]-[total amount of Mo in the R/2 release]≤0.03.
EFFECT: providing high resistance to stress corrosion cracking (SCC) and resistance to sulphide cracking under stress (SSC).
3 cl, 2 dwg, 2 tbl
