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[en] Investigations of percentage reduction in area during cold rolling is shown to have a noticeable effect on texture of thin-sheet corrosion-resistant steel O8Kh18N10T - by increase of deformation degree the number of crystallites with disordered orientation is reduced. Crystallographic texture { 112 } <111>, { 111 } <110>, defining high values of normal plastic anisotropy and strain hardening for thin-sheet steel rolled with the deformation degree of 65-70 %, the relative quantity of crystallographic texture { 110} <112> being reduced, is considered to be a favourable texture regarding stamping
Journal
[en] The aim of the present investigation is to determine the influence of plasticity-induced martensite formation on the cyclic deformation behaviour of the metastable austenitic stainless steel X6CrNiTi1810 (German material number 1.4541) in single- and multiple-step-tests at room temperature and T=300 C. Several specimen batches were tested under stress, total strain and plastic strain control with different R-values, a frequency of 5 Hz (HCF) respectively 0,1 Hz (LCF) and triangular load-time functions, σ,ε-hysteresis and nondestructive magnetic measurements were used to characterize the fatigue behaviour. At room temperature and T=300 C the cyclic deformation behaviour is characterized by cyclic softening and hardening phases, which are strongly influenced by the loading conditions. A certain amount of accumulated plastic deformation has to be exceeded to initiate the martensite formation. The martensite formation varies with the loading conditions, temperature and number of cycles. At T=300 C, only low fractions of plasticity-induced martensite were formed and therefore highly sensitive magnetic sensors are necessary to detect phase transformations in fatigued specimens. The experiments yield characteristic cyclic deformation curves and martensite fractions corresponding to the actual fatigue state. Cyclic creep was determined in experiments with positive and negative mean stresses. The martensite formation is enhanced by positive mean stresses. A significant influence of positive or negative mean strains on the martensite formation behaviour could not be determined, due to the fast and nearly complete relaxation of the mean stresses. Light, electron microscopic and X-ray diffraction investigations confirm the nondestructive magnetic results with the measured fatigue state of the material. (orig.)
[de]
Ziel der vorliegenden Arbeit war, quantitative Zusammenhaenge zwischen dem zyklischen Verformungsverhalten und der verformungsinduzierten Martensitbildung des metastabilen austenitischen Stahles X6CrNiTi1810 (Werkstoff-Nr. 1.4541) aus ein- und mehrstufigen Wechselverformungsexperimenten bei Raumtemperatur und T=300 C zu ermitteln. Dazu wurden spannungs-, totaldehnungs- und plastisch dehnungskontrollierte Versuche mit einem dreieckfoermigen Beanspruchungs-Zeit-Verlauf bei einer Frequenz von 5 Hz (HCF) bzw. 0,1 Hz (LCF) durchgefuehrt. Zur Charakterisierung des Ermuedungsverhaltens diente neben den aus σ,ε-Hysteresen ermittelten mechanischen Kennwerten, der mittels zerstoerungsfreier magnetischer Messverfahren gemessene Martensitanteil. Das Wechselverformungsverhalten ist bei RT und T=300 C von zyklischen Ver- und Entfestigungsvorgaengen gekennzeichnet, die stark von den Beanspruchungsbedingungen abhaengig sind. Damit eine Martensitbildung einsetzt, muss eine bestimmte kumulierte plastische Dehnung ueberschritten werden. Durch Variation der mechanischen Beanspruchungsparameter, der Temperatur und der Lastspielzahl kann das Martensitbildungsverhalten gezielt beeinflusst werden. Bei einer Versuchstemperatur von T=300 C wird wesentlich weniger Martensit gebildet, der nur mit hochaufloesenden Magnetfeldsensoren gemessen werden kann. Ein eindeutiger Zusammenhang zwischen dem Wechselverformungsverhalten und der verformungsinduzierten Martensitbildung wird bei beiden Versuchstemperaturen beobachtet. Bei spannungskontrollierten Versuchen mit ueberlagerten Mittelspannungen wurde zyklisches Kriechen festgestellt. Positive/negative Mittelspannungen beschleunigen/verzoegern die Martensitbildung. Da die in totaldehnungskontrollierten Versuchen mit ueberlagerten Mitteldehnungen auftretenden Mittelspannungen sehr schnell und fast vollstaendig relaxieren wird das Martensitbildungsverhalten praktisch nicht beeinflusst. Licht-, elektronenmikroskopische und roentgenographische Untersuchungen bestaetigen die zerstoerungsfreien magnetischen Messungen des aktuellen Ermuedungszustands. (orig.)Source
Werkstoffkundliche Berichte; v. 6; 1999; 219 p; ISBN 3-932066-05-7; 
; ISSN 1433-2744; ; Available from TIB Hannover: RR 8068(6); Diss. (Dr.Ing.)
; ISSN 1433-2744; ; Available from TIB Hannover: RR 8068(6); Diss. (Dr.Ing.)
[en] The technology of producing corrosion-resistant 08-12Kh18N10T steel using new technological operations during out-of-the-furnace steel treatment is developed and exploited. The reduction of gas saturation of steel delivered to the machine of continuous casting, the decrease in the amount of nonmetallic inclusions, stabilization of the process in temperature and rate contribute to the increase in quality of continuously casted slabs
Journal
[en] The steelmaking practice for corrosion steel 12Kh18N10T providing for simultaneous chromium oxidation and decarbonization and chromium reduction from slag using carbon-containing reducers is proposed. As a result the total chromium flow rate decreases by 15.7 kg/t. The quality of tested metal in macro- and microstructure corresponds to the indices of metal melted according to the present-day practice. The ductility of the former in the 1000-1270 deg C temperature range is by 10-30% higher than that of the latter
Journal
[en] It is proposed to modify the design of the device for oxygen lancing of the liquid bath in order to reduce chromium consumption during smelting of the Kh18N10T stainless steel. As a result of a more thorough stirring of the bath by oxygen jets the chromium and titanium pickup increases and the blow duration decreases. This causes a decrease in the furnace liner wear
Journal
[en] The localization features of the deformation accompanying the Portevin-Le Chatelier effect were studied in the austenitic stainless steel 12Kh18N10T bombarded with the neutron fluence of 2 x 1024 neutrons/m2. An appropriate experimental technique was developed and the measurements were made for the front width of the band, the front propagation velocity, and the deformation rate in the band. Neutron bombardment was found to produce a more significant variation of the band parameters with an increase in the strain rate. (author)
Journal
[en] Evaluation of the quality of joints of steel pipe-lines of small diameter, soldered by high-temperature solders after special treatment (shape formation) of tube edges before assembly is given. Tubes of 12Kh18N10T steel are used for pipe-line fabrication. It is shown that cooperative heating of shaped tips of pipe-lines with turned valves does not change their geometric sizes
Journal
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