DEPENDENCE OF PHYSICAL, STRUCTIONAL AND SENSITIVE PROPERTIES AND ALLOYED STEEL HARDNESS ON THE COMPOSITION AND HEAT TREATMENT

Abstract

In the article it’s defined the changes of the coercive force (Hc), electrical resistivity (ρ), magnetization saturation (4πI_s) and hardness (HRC) of the structural steel after hardening and tempering at 200º…700ºC. Indicators of physical properties 18X2H4BA, 30XГCHA, 38XH3MФA, 20X3BMФ, 35X5BMФC, 60C2XФA, 30X2MФ, 35X2M2T, 30X5H5M2ЮT, 30X14HMC, 30XH10K5M2Ф, 25XH10K10M2Ф, H16M2TЮ, H10X10K2MT2, H13K14M9 and others were compared with the indexes of C steel 45, the coercive force of the tool (9XC, X12Ф1, 8X14MT, 7XCMT, 65X3ГCBMФ, 45X6M2ФC, P6M5, P18, etc.) and hard-magnetic (EX9K15M) steels. H_c max was received after hardening in steels with the carbide strengthening, H_c decreases at temperature rising. The additive agents C, Cr, Si, Mo, Co increase Hc. The largest value Hc max was got for the hard magnetic steel EX9K15M. In the steels with the intermetallic strengthening (maraging steels) Hc max was received not after tempering and ageing at HRCmax (500ºC) but after re-ageing (at 700ºC) when 4πI_s is at minimum value. The index 4πI_s is affected by the chemical composition, temperatures of hardening and tempering. The maximum ρ value is received for all steels after hardening; with the T_temp rising ρ decreases. ρ is affected by the percentage of C and alloy additives. Hardness HRC depends on the percentage of C, alloy additives, T_hard and T_temp.