Andreas Weiß

Technische Universität Bergakademie Freiberg · Institute of Iron and Steel Technology

This paper presents a systematic study of quenching and partitioning (Q&P) processing of a (C + N)-containing austenitic stainless steel with a special focus laid on the influence of partitioning conditions on the mechanical properties and its comparison with C-containing Q&P-treated stainless steels. Similar to C-containing stainless steels, marte...

The deformation-induced formation of α′-martensite was investigated by tensile testing of a X5CrNi18-10 wrought austenitic steel and X3CrMnNi16-7-3/6/9 (Ni contents of 3, 6, and 9 mass%) as well as X15CrNiMnN19-4-3 cast austenitic steels at temperatures between −80 and 400 °C. The results were presented in the form of Stress-Temperature-Transformat...

This chapter is centered on the development of austenitic high strength cast CrMnNi steels with excellent strength-ductility combination by triggering TWIP and TRIP effects. Special attention is given to obtain a high yield strength and a good formability. For this purpose, three generations of steels were developed. The 1st generation is comprised...

The article presents the mechanical properties of the austenitic stainless steel X5CrMnNiMoN16-4-4 after deformation by cold rolling and subsequent short-term tempering (deformation and partitioning (D&P) treatment). Tensile strengths of 1700–900 MPa and beyond were achieved both after work hardening and in the D&P-treated strip. The initial state...

The generation of a nickel-reduced, stainless spring steel strip with a thickness of 0.2 mm, producible under industrial conditions, is the aim of a transfer project together with the Institute of Metal Forming/TU BAF and the Auerhammer Metallwerk GmbH within the DFG Collaborative Research Centre (CRC) 799. The spring steel strip should exhibit a t...

The influence of martensite formation on the mechanical properties of an Fe–16Cr–6Ni–6Mn (concentrations in wt%) austenitic stainless steel is studied by tensile tests between −70 and 300 °C. As‐quenched martensite formation is observed at temperatures below −30 °C. Deformation‐induced α′ martensite formation, on the other hand, is triggered below...

This work is focused on the magnetic determination of martensite phase contents and characteristic temperatures in a Fe-30Ni steel alloy. To achieve this, magnetic saturation measurements and thermomagnetic measurements are applied. Due to the presence of ferromagnetic austenite in the alloy's microstructure, an own lab calibration for magnetic sat...

A new austenitic stainless CrMnNi steel with a high cold formability coupled with high strength was developed. The cold formability is based on the distinct transformation induced plasticity (TRIP) and twinning induced plasticity (TWIP). Thereby a maximum of strain is reached nearby room temperature. Using the TRIP/TWIP effect of CrMnNi steel a cos...

This investigation focuses on deformation-induced plasticity in Invar-type steel alloys. The effect is being studied in an austenitic model alloy, containing 30 wt-% of nickel. Its temperature dependent mechanical properties are being presented. Furthermore, the martensitic phase content has been determined by magnetic means in an alloy with two fe...

A novel quenching and partitioning (Q&P) processing was applied to the steel Fe-15Cr-3Ni-3Mn-0.5Si-0.12N-0.16C (wt.-%) with an almost fully austenitic microstructure in the solution annealed condition. The Q&P processing consisted of a subzero cooling step and a partitioning step at 450 °C. The fraction of ʼ-martensite after the Q&P processing was...

Im Zentrum der Untersuchung steht der α-TRIP-Effekt. Dieser wird an einer Modelllegierung, einem austenitischen Stahl mit hoher Stapelfehlerenergie, isoliert betrachtet. Die temperaturabhängigen mechanischen Eigenschaften, gewonnen aus einer Fließkurvenanalyse, werden dargestellt. Dabei zeigt sich, dass der α-TRIP-Effekt mit primär welligem Versetz...

Am Institut für Eisen- und Stahltechnologie der TU Bergakademie Freiberg wurde in einem vom Bundesministerium für Bildung und Forschung (BMBF) geförderten Forschungs- und Entwicklungsprojekt (033R073B) ein metastabiler austenitischer CrMnNiN-Stahl entwickelt. Aus dieser Legierung wurden in einer industriellen Kleincharge 1,25 mm bis 0,1 mm dünne Fe...

The austenite-stabilizing effect of carbon on the martensitic transformation behavior and the temperature dependent tensile properties of five Fe–15Cr–3Mn–3Ni–0.1N–(0.05–0.25C) cast stainless steels with austenitic and austenitic-martensitic microstructures was studied. As the carbon concentration increased in 500 ppm increments from 0.05 mass-% to...

The formability of a novel metastable Fe-15Cr-3Mn-3Ni-0.2C-0.1N austenitic TRIP/ (TWIP) steel was investigated by cold rolling and rolling at elevated temperatures for different base materials. One was an as-cast material while the other was a hot-rolled one, with resulting differences in structure. The base material was characterized by the grain...

An der TU Bergakademie Freiberg, Institut für Eisen- und Stahltechnologie, ist ein neues Verfahren zur Nutzung des TRIP-Effekts in martensitischen Stählen entwickelt worden. Gemeinsam mit dem Fraunhofer Institut für Werkzeugmaschinen und Umformtechnik in Chemnitz ist das Verfahren an umwandlungsträgen Vergütungsstählen getestet worden. Die vorliege...

In metastable austenitic stainless steels, the formability is very limited due to the accelerated stress-induced αʼ-martensite formation below the yield strength (YS). The Fe-15Cr-3Mn-3Ni-0.5Si-0.10N-0.15C (wt.-%) cast austenitic stainless steel, Cr15NC10.15 in short, serves as an appropriate example of this material behavior. After solution anneal...

The paramagnetism of austenite and the ferromagnetism of α’-martensite in Fe-Cr-Mn-Ni steels enable the determination of the deformation-induced α’-martensite content with the aid of magnetic based methods. For this purpose, an in-situ magnetic measurement system was devised to determine the kinetics of deformation-induced martensite formation duri...

In spite of the formation of a high fraction of deformation-induced α′ martensite, the tensile elongation of a cast high-nitrogen austenitic stainless steel was found to enhance at lower temperatures, a behavior deviating from that exhibited by wrought and homogenized austenitic stainless steels. The observed behavior was explained by the presence...

Am Institut für Eisen- und Stahltechnologie der TU BAF sind ultrahochfeste Stähle mit gleichzeitig relativ hohen Zähigkeitseigenschaften entwickelt worden. Diese Stähle stellen eine bedeutende Weiterentwicklung der konventionellen AHSS (Advanced-High-Strength-Steels) dar. Die hervorragende Kombination von Festigkeits- und Zähigkeitseigenschaften be...

The deformation-induced processes by tensile loading of X5CrNi18-10 austenitic stainless steel in the temperature range of 77 K to 413 K (−196 °C to 140 °C) were investigated. The results were presented in the form of stress–temperature-transformation (STT) and strain–temperature-transformation (DTT) diagrams. The thermodynamic stability of the aus...

The microstructural evolution and mechanical properties of two cast Fe-15Cr-6Mn-3Ni-0.5Si-0.2N-0.1C (concentrations in wt pct) steels containing no vanadium and 0.65 wt pct vanadium were investigated under uniaxial tensile loading for room temperature (RT) and 373 K (100 °C). The alloy development was focused on the formation of nanosized vanadium...

An in-situ magnetic device was employed to quantify the deformation-induced martensite in a Fe-19Cr-3Mn-4Ni-0.15C-0.15N (wt.-%) steel during tensile testing in the temperature range of -40°C to 22°C. The new device consists of an electromagnetic field which serves to magnetize the martensite phase as it forms during tensile loading and a second coi...

In this study, the austenite-stabilizing effect of manganese in as-cast Fe–(12–16)Cr–(0–13)Mn–6Ni (concentrations in wt%) stainless steels was investigated by means of light optical microscopy (LOM) and magnetic scale measurements. The well known Schaeffler-diagram was used for the prediction of the microstructure at room temperature. Major deviati...

In the present work the influence of phosphor on the flowability, the effect on the infiltration of ZrO2 open foam ceramics and the martensite formation as well as the resulting mechanical properties of high alloyed CrMnNi as-cast steels is studied. Additionally, the effect of phosphor on surface tension is investigated. The study is performed usin...

Cast austenitic Fe-Cr-Mn-Ni steels are characterized by an excellent combination of strength and ductility. The present study aims to describe the mechanical properties of an Fe-19Cr-3Mn-4Ni-0.15N-0.2C cast steel in view of the plasticity mechanisms involved namely the dislocations glide in the austenite, the transformation-induced plasticity (TRIP...

The effect of the manganese content (0–11%) on the transformation temperatures, the mechanical properties and microstructure development of five highly alloyed 14Cr–XMn–6Ni cast stainless steels with 0.1% nitrogen was studied. The examinations reveal that the Ms, As, and Af temperatures decrease with increasing manganese contents. As a result of lo...

The microstructure evolution during deformation and the mechanical behavior of an austenitic Cr-Mn-Ni as cast steel are investigated at various temperatures. The deformation-induced twinning and Ïμ/α′- martensite formation - the TWIP and TRIP effects - occur in the investigate steel depending on the deformation temperature. For characterization and...

Tidemarschen sind Schnittstellen zwischen terrestrischen und aquatischen Ökosystemen. Sie sind für ihre Transformationskapazitäten in Bezug auf anorganische und organische Nährstoffe bekannt und können laterale Nährstoffflüsse in der Küstenzone beeinflussen. In dieser Studie wurden die Tidemarschen des Elbe Ästuars, Deutschland, in Bezug auf den Si...

a b s t r a c t High-alloyed cast TRIP steel showing pronounced martensitic phase transformation during plastic deformation like tensile, compressive or cyclic loading exhibits concurrently high strength and high ductility. Further increase in the yield strength/ultimate tensile strength can be realized by a smaller austenitic grain structure. An u...

The epsilon martensite phase was investigated in three types of FeMn(Cr) steels by means of metallographic, EBSD and XRD methods as well as by dilatometric and DSC examinations during heating and cooling. In the course of the latter examinations, the transformation temperatures (Ms, A(s)) of epsilon martensite were determined in the previously defo...

A new austenitic cast steel from the type X4CrMnNil6 7 6 or X4CrMnNil6 7 7 is presented. The steel has a relatively low stability of the austenite with respect to the martensitic transformation to the e- and a'-martensite phase and a relatively slow stacking fault energy to its chemical composition. Both influencing variables cause a TRIP/TWIP effe...

The mechanical behavior and microstructure evolution during deformation of novel austenitic Cr–Mn–Ni as-cast steels with varied Ni content were investigated at various temperatures using static tensile tests, optical microscopy, and the magnetic scale for the detection of ferromagnetic phase fraction. To summarize all knowledge about the deformatio...

Three differently alloyed austenitic FeMn(Cr) steels have been examined with a focus on the occurrence of ε martensite. Studies primarily focus on the detection of ε martensite by means of metallographic and X-ray methods as well as by means of dilatometric and DSC measurements. Dilatometric and DSC measurements have also been carried out to determ...

Stress-Temperature-Transformation (STT) and Deformation-Temperature-Transformation (DTT) diagrams are well-suited to characterize the TRIP (transformation-induced plasticity) and TWIP (twinning-induced plasticity) effect in steels. The triggering stresses for the deformation-induced microstructure transformation processes, the characteristic temper...

Modern steel developments often use additional deformation mechanisms like the deformation induced martensitic transformation (TRIP-effect) and mechanical twinning (TWIP-effect) to enhance elongation and strength. Three high-alloyed cast CrMnNi-steels with different austenite stabilities were examined. Dependent on the austenite stability, TRIP-eff...

The martensite start temperature (Ms), the martensite austenite re-transformation start temperature (As) and the re-transformation finish temperature (Af) of six high alloyed Cr-Mn-Ni steels with varying Ni and Mn contents in the wrought and as-cast state were studied. The aim of this investigation is the development of the relationships between th...

The temperature dependence of the martensite formation and the mechanical properties of three high alloyed Cr-Mn-Ni as-cast steels with varying Ni contents were studied. The results showed that the Ms and Md temperatures of the steels decrease with increasing nickel contents. Therefore the strain-induced martensite formation, the TRIP effect and th...

Stress-Temperature-Transformation (STT) and Deformation-Temperature-Transformation (DTT) diagrams are suitable to characterize the TRIP (transformation-induced plasticity) and TWIP (twinning-induced plasticity) effect in steels. The triggering stresses for the deformation-induced microstructure transformation processes, the characteristic temperatu...

The temperature dependence of the martensite formation and the mechanical properties of three high alloyed Cr-Mn-Ni as-cast and wrought steels with varying Ni contents were studied. The results showed that the Ms and Md temperatures of the steels decrease with increasing nickel contents. Therefore, the strain-induced martensite formation, the TRIP-...

Kurzfassung Das Fließspannungsverhalten einer hochlegierten metastabilen Stahlgusslegierung wurde in einem weiten Bereich der Dehnrate (4·10 ⁻⁴ s ⁻¹ bis 2200 s ⁻¹ ) unter Zug- und Druckbeanspruchung untersucht. Dabei wurde ein ausgeprägter TRIP(TRansformation Induced Plasticity)-Effekt der austenitischen Legierung auf CrMnNi-Basis beobachtet, welch...

Metastable austenitic steels show excellent mechanical properties, such as high strength combined with excellent ductility and toughness due to martensitic transformation under mechanical loading (transformation induced plasticity effect). A good energy consumption, and, in the case of high-alloyed metastable austenitic steels, a high corrosion res...

Neue am Institut für Eisen- und Stahltechnologie entwickelte und gemeinsam am Institut für Fahrzeugkonzepte des Deutschen Zentrums für Luft- und Raumfahrt getestete Cr-Mn-Ni-Stähle mit dem TRIP/TWIP Effekt verfügen im Vergleich mit herkömmlichen austenitischen Cr-Ni-Stählen über bessere Festigkeits- und Plastizitätseigenschaften. Die ausgezeichnete...

Новые, разрабатываемые в в Институте Технологии Чугуна и Стали, Cr-Mn-Ni-стали с TRIP/TWIP-эффектом обладают в сравнении с традиционными хромоникелевыми аустенитны¬ми сталями улучшенными прочностными и пластичными свойствами, вызванными мартенситным превращением при пластической деформацией. Возможное атермическое или изотермическое образование мар...

Material Behaviour of a Cast TRIP/TWIP-Applicable CrMnNi-Based Steel up to High Strain Rates. The mechanical behaviour of a high alloyed and meta-stable cast steel alloy was examined under tensile and compressive loading in a wide range of strain rate (4.10(-4) S(-1) up to 2200 S(-1)). The CrMnNi-based alloy showed a distinctive TRIP-effect, result...

Cast high alloyed metastable austenitic CrMnNi-TRIP-steels are rather novel corrosion resistant materials and still under development. Due to the transformation-induced plasticity effect (TRIP) high stresses combined with high ductility can be achieved up to high strain rates of 103 1/s. Deformation temperatures and strain rate influence the marten...

Weltweit verstärken sich die Bemühungen bei der Suche nach kostengünstigen austenitischen Stahlgüten mit hohem Energieabsorptionsvermögen. Dabei zeichnen sich verschiedene Forschungsrichtungen ab, die sich auf Stähle mit TRIP‐, TWIP‐ und SBIP‐Effekt ¹⁾ oder entsprechenden Kombinationen konzentrieren. Am Institut für Eisen‐ und Stahltechnologie der...

Nb alloyed ferritic Cr-steel is usually produced by continuous casting with following hot and cold rolling procedure. In the laboratory scale the possible new route via strip casting was studied. The scope of the investigation in simulated process route was the development of microstructure and precipitations. In the experiments process parameters...

The knowledge of the stress- and deformation-induced martensite formation in metastable austenitic steels including the formation temperatures and amounts formed is of considerable importance for the understanding of the transformation induced plasticity. For this purpose a stress-temperature- transformation (STT) and a deformation-temperature-tran...

The Institute of Iron and Steel Technology was founded more than 130 years ago. In the 90s and in the last years the institute was equipped with modern devices for vacuum melting, casting and heat treatment, the slag laboratory was enlarged, the analytic laboratory completed and the material development and metallography were strengthened with new...

For the production and further processing of the austenitic CrNi steels the cold workability is a significant property in addition to the corrosion resistance. The high cold deformation behaviour of these steels is caused to a high degree by the trip effect. This article of the TU Bergakademie Freiberg deals with methods concerning material ressour...

Deformation behaviour of Type AISI 304 stainless steel was evaluated by uniaxial tensile testing at different temperatures ranging from -60°C to 200°C. The strengthening mechanisms of strain-induced, transformation of austenite to martensite and variant conversions have been discussed. Ludwigson and Berger's transformation kinetics relationship has...

Iron manganese steels with Mn mass contents of 15 to 30 % exhibit microstructural related superior ductility and extraordinary strengthening behaviour during plastic deformation, which strongly depends on the Mn content. This influences the austenite stability and stacking fault energy γ fcc and shows a great impact on the microstructure to be deve...

The TRIP effect in austenitic stainless steels leads to temperature dependent mechanical properties. As this is caused by stress or strain induced austenite/martensite transformation a predeformation at low temperatures (cryoforming) will change the microstructure and the transformation behaviour of the remaining austenitic constituent. The mechani...

Entry into S phase of the mitotic cell cycle is normally strictly dependent on progression through the preceding M phase. In contrast, during endoreduplication, which accompanies post-mitotic cell growth in many organisms, repeated S phases occur without intervening M phases. Upon transition from mitotic to endoreduplication cycles in Drosophila em...

The effect of cryoforming at 77 K on the flow and work-hardening characteristics was investigated considering the martensitic transformation behaviour in austenitic Cr Ni steels with different nickel contents. The test steels can be divided into two groups relating to the flow and work-hardening characteristics and martensitic transformation behavi...