Die Zeit‐Temperatur‐Ausscheidungs‐Diagramme und die sich daraus ergebenden Zeit‐Temperatur‐Sensibilisierungs‐Diagramme werden vorgestellt für die heute üblichen NiCrMo‐Legierungen C‐4 (2.4610), C‐276 (2.4819), 22 (2.4602) und die neuentwickelte Legierung 59 (2.4605), desgleichen für die Legierung 625 (2.4856), die aufgrund ihres hohen Niob‐Gehaltes eine Sonderstellung einnimmt, und ergänzend für die Legierung G‐3 (2.4619). Von diesen Werkstoffen hat die Legierung C‐276 (2.4819) die stärkste Neigung, im mittleren Temperaturbereich die Intermetallischen Phasen μ und P in Verbindung mit M6C‐Karbid auszuscheiden, hierin gefolgt von den Werkstoffen 22 (2.4602) und 59 (2.4605). Die Neigung zur Sensibilisierung im Sinne des 50 μm Eindringtiefe‐Kriteriums der interkristallinen Korrosion (IK) im Test gemäß ASTM G‐28, Methode A ist bei der Legierung C‐276 (2.4819) sehr groß und nimmt ab in der Reihenfolge der Legierungen C‐4 (2.4610), 22 (2.4602), 59 (2.4605), G‐3 (2.4619), 625 (2.4856). Die Sensibilisierung ist eine Folge der Ausscheidungen der intermetallischen Phasen μ und P in Verbindung mit M6C‐Karbidausscheidung bei der Legierung C‐276 (2.4819) und wahrscheinlich auch im Fall der Legierungen 22 (2.4602) und 59 (2.4605). Bei den Legierungen C‐4 (2.4610), G‐3 (2.4619) und 625 (2.4856) ist sie eine Folge von Karbidausscheidungen. Eine sehr hohe thermische Stabilität im Sinne des 50 μm IK‐Kriteriums in oxidierenden Testlösungen kann am leichtesten bei Legierungen mit einem Cr/(Mo + W)‐Verhältnis > 1,3 realisiert werden. Das sind die Legierungen 59, 625 und G‐3. Die für die Ermittlung der Sensibilisierung üblichen stark oxidierenden Prüflösungen (ASTM G‐28, Methode A und SEP 1877/II) sind nur im Fall der hoch in Chrom legierten Werkstoffe wirklich sinnvoll, während sie im Fall der Legierung C‐276 (2.4819) nicht den Anwendungsfeldern dieses Werkstoffes entsprechen.

mechanical mixing and the resulting microstructure of their alloys. The spectrum includes various materials (steel, high entropy alloys, and nonferrous alloys) as well as mixtures of prealloyed and/or elemental powders. [1,2] Particle size, morphology, and density were reported to play a role in LPBA. [3] Mindt et al. [4] as well as Shaheen et al. [5] reported a tendency of small particles depositing at the beginning of the recoating movement by modeling the powder application process. Jacob et al. [6] stated the same phenomena in their experiments. Fereiduni et al. [7] observed free fine particles when adding fine B 4 C to Ti-6Al-4 V base material. The amount of nonbond fine powder can be reduced by ball milling of 3 h and more. Ball milling is accompanied by plastic deformation of the base powder leading to variations from the original spherical shape.Hot cracks are a known phenomenon in additive manufacturing (AM), which were observed by various researchers for different alloys: nickel-based materials, [8,9] tungsten, [10] aluminum-based alloys, [11] and steels. [12] Hot cracks form during solidification as the residual melt is trapped between solidified grains/dendrites and the melt flow in the interdendritic space is hindered. Shrinkage resulting from the cooling of the alloy leads to a crack initiating strain. The solidification interval is agreed on to play a significant role in hot cracking. [13] Segregations in the residual melt lead to a depressed solidus point of interdendritic areas and can contribute to the cracking. [14] Known routes for hot crack elimination are: alloy modification, process modification, post-processing, e.g., hot isostatic pressing. [9] In this study, the approach of alloy modification is chosen to reduce the hot cracking tendency of AISI H13 hot work tool steel.Li et al. [10] observed a reduced cracking tendency in W alloy with Ta additives. The in situ oxidation of Ta leads to the formation of primary oxides which can act as heterogeneous nucleation sites for solidification. In addition, the oxides lead to a reduction of grain boundary segregation and enhance their strength.High carbon steels show a tendency for cold crack formation during laser poder bed fusion (LPBF) processing. Cold cracks in welding are described as spontaneously occurring cracks at temperatures after solidification. Whereas hydrogen can influence embrittlement, these cold cracks in LPBF are mainly attributed

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Strength and ductility have been evaluated on various alloy 625 compositions, including carbon contents between 0.009 and 0.045 wt. % and iron contents between 1.1 and 4.2 wt. %. Grain size was between ASTM No 3 and 7. Aging treatments at 600, 700 and 800°C up to 1000 hrs duration cause an increase of yield strength, being accelerated when aging is carried out at 700°C but with highest tensile elongation after aging at 600°C. Accordingly accompanying loss of IS0 V-notch impact strength is least pronounced after aging at 600°C but more severe when the iron content is at 4.2 wt. % compared to lower iron alloyed material. The influence of carbon content on creep strength is the more pronounced the higher the temperature. If 10,000 and 30,000 hrs creep-rupture stress is considered, the influence of carbon is small at 650°C and more distinct at 850°C. In changing ASTM grain size No from 6 to 3 the 30,000 hrs creep-rupture stress is increasing by about 4 % at 650°C and by about 43 % at 850°C. If creep stress for 1 % strain at 750 and 850°C is considered, the influence of carbon is very strong at carbon contents up to about 0,025 wt. %, improving 30,000 hrs creep stress for 1 % strain at 850°C by about 700 % when carbon content is increased from 0.015 to 0.025 wt. %. Creep deformation may be supposed to improve with decreasing carbon content.

Alloy 33 (UNS-R20033), a new corrosion-resistant austenitic material based on chromium (mass fraction of the elements, %: 33 Cr; 32 Fe; 31 Ni; 1.6 Mo; 0.6 Cu; 0.4 N), appeared on the market in 1995. In this paper, we present new data on its mechanical properties, formability, weldability, activation characteristics, and behavior under corrosion conditions. We have established that the mechanical properties of welded articles, including impact toughness, are a good match for the same properties of plates, allowing plastic deformation without fracture. When held for up to 8 h at a temperature from 600~ to 1000*C, the alloy is not activated in boiling azeotropic nitric acid (the Huey test). In tests under service conditions, alloy 33 displays exceptional corrosion resistance in 96-98% H2SO 4 at 135-140"C and in 99.1% H2SO 4 at 150"C. Alloy 33 also has rather successfully undergone testing in 96% H2SO 4 with nitrosyl impurities at 240"C. In nitric acid, alloy 33 is resistant at a concentration up to 85% at 75"C and even higher temperatures. The alloy also has corrosion resistance in 1 M HCI at 40"C and in NaOH/NaOCI solutions. In artificial sea water, the pitting potential remains unchanged at temperatures up to 75"C and also is much higher than the oxidation-reduction potential of sea water at 95"C.Alloy 33 is easily formed; articles of any required shape can be made from it. The new data confurm the generalpurpose nature of the ~alloy, which allows it to meet the diverse requirements of chemical technology, oil and gas, and oil refining industries.Alloy 33 was developed in the 1990's with the goal of obtaining exceptional corrosion resistance under conditions of a strongly oxidizing medium and overcoming problems arising in fabrication and welding of articles with large cross sections made from superferritic corrosion-resistant steels [1]. Furthermore, manufacturers of components of steels sometimes required material with higher structural stability for replacing the corrosion-resistant fractions with high molybdenum content. As a result, the described alloy was developed: a solid solution based on chromium, alloyed with nickel and nitrogen impurities for stabilization of the austenitic microstructure.The corrosion resistance of steel is enhanced as a result of adding molybdenum and copper impurities. As established in [2], the nominal pitting resistance equivalent (PRE) of the new steel is 50, which is higher than the PRE of 6% molybdenum austenitic corrosion-resistant steel and alloy 626 based on nickel. We should also note that, despite the presence of chromium and nitrogen, alloy 33 displays a high degree of thermal stability, which may be explained by the austenitic microstructure and balanced chemical composition.Weldability and Activation Behavior. As shown by the tests carried out according to ISO requirements, the impact toughness of alloy 33 is 280 J/m 2. After arc welding of a plate of thickness 15 mm with a tungsten electrode in a shielding gas medium (GTAW, Gas Tungsten Arc Welding) with the same mater...