scholarly journals Hydrogen Embrittlement of the Additively Manufactured High-Strength X3NiCoMoTi 18-9-5 Maraging Steel

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5073
Author(s):  
Angelina Strakosova ◽  
Michaela Roudnická ◽  
Ondřej Ekrt ◽  
Dalibor Vojtěch ◽  
Alena Michalcová
Keyword(s):  
Heat Treatment ◽  
Hydrogen Embrittlement ◽  
Maraging Steel ◽  
Tensile Testing ◽  
High Strength ◽  
Fracture Surface Morphology ◽  
Laser Melting ◽  
Heat Treated ◽  
Before And After ◽  
A Current

The main aim of this study was to determine the susceptibility of the additively manufactured high strength X3NiCoMoTi 18-9-5 maraging steel to hydrogen embrittlement. For this purpose, samples produced by selective laser melting technology, before and after heat treatment, were used. The examined samples were electrochemically charged with hydrogen in NaCl + NH4SCN solution at a current density of 50 mA/cm2 for 24 h. The H content increased from about 1 to 15 ppm. Heat treatment did not affect the amount of H trapped in the maraging steel. Tensile testing revealed that the tensile strength of the H-charged samples was much lower than that of the uncharged samples. Moreover, the material became brittle after charging compared to the ductile as-printed and heat-treated samples with elongation values of 7% and 2%, respectively. The loss of plasticity was confirmed by fractography, which revealed transformation of the fracture surface morphology from dimple-like in the as-produced state to a brittle one with smooth facets in the H-charged state.

Comparison of Microstructure and Mechanical Properties of Additively Manufactured and Conventional Maraging Steel

2020 ◽  
Vol 405 ◽  
pp. 133-138
Author(s):  
Ludmila Kučerová ◽  
Andrea Jandová ◽  
Ivana Zetková
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Maraging Steel ◽  
Precipitation Hardening ◽  
High Strength ◽  
Hardness Measurement ◽  
Nickel Steel ◽  
Heat Treated ◽  
Good Material ◽  
Iron Nickel

Maraging steel is an iron-nickel steel alloy, which achieves very good material properties like high toughness, hardness, good weldability, high strength and dimensional stability during heat treatment. In this work, maraging steel 18Ni-300 was manufactured by selective laser melting. It is a method of additive manufacturing (AM) technology, which produces prototypes and functional parts. Sample of additively manufactured and conventional steel with the same chemical composition were tested after in three different states – heat treated (as-built/as-received), solution annealed and precipitation hardened. Resulting microstructures were analysed by light and scanning electron microscopy and mechanical properties were obtained by hardness measurement and tensile test. Cellular martensitic microstructures were observed in additively manufactured samples and conventional maraging steel consisted of lath martensitic microstructures. Very similar mechanical properties were obtained for both steels after the application of the same heat treatment. Ultimate tensile strengths reached 839 – 900 MPa for samples without heat treatment and heat treated by solution annealing, the samples after precipitation hardening had tensile strengths of 1577 – 1711 MPa.

Casting and Heat Treatment of Turbocharger Impellers Thixocast from Alloy 201

2012 ◽  
Vol 192-193 ◽  
pp. 556-561 ◽  
Author(s):  
Qiang Zhu ◽  
Stephen Midson ◽  
Chang Wei Ming ◽  
Helen V. Atkinson
Keyword(s):  
Heat Treatment ◽  
High Strength ◽  
Heat Treatment Condition ◽  
Hot Tearing ◽  
Alloy Casting ◽  
Heat Treated ◽  
Before And After ◽  
Optimum Heat ◽  
Semi Solid ◽  
Optimum Heat Treatment

Commercial semi-solid cast impellers are produced from Al-Si-Cu alloys heat treated to the T6 temper. The study described in this paper involved the identification of casting and heat treatment parameters to produce semi-solid processed turbocharger impellers from a silicon-free, higher strength 201 alloy. Casting parameters were identified which minimized hot tearing in the alloy 201 impellers. A series of heat treatment studies were performed to determine optimum heat treatment parameters. The T71 temper was identified as the preferred heat treatment condition to produce high strength as well as superior elongation. The results from mechanical property measurements conducted on the T71 heat treated impellers are reported. Optical and scanning electron microscopy (SEM) were also used to characterize the microstructure of alloy 201 impellers before and after heat treatment, and representative microstructures are presented.

The Effect of Heat Treatment on Formability of Ultra-Fine Grained AA6061 for Bolt Manufacturing

2010 ◽  
Vol 443 ◽  
pp. 164-169 ◽  
Author(s):  
Jun Seok Choi ◽  
Young Gwan Jin ◽  
Yong Taek Im
Keyword(s):  
Heat Treatment ◽  
Artificial Aging ◽  
Equal Channel Angular Extrusion ◽  
High Strength ◽  
Strength Increase ◽  
Fine Grained ◽  
Heat Treated ◽  
Before And After ◽  
Fine Grained Material ◽  
Set Up

Equal channel angular extrusion (ECAE) was used before and after artificial aging to investigate the effect of heat treatment on formability of bulk nanostructure of commercially available aluminum alloy of AA6061 in the present study. In the ECAE, route A was applied up to four or eight passes by using the split dies set-up. The three-stage bolt forming using the ultra-fine grained specimens was carried out to check formability of the material. In the present experiments, the bolt forming was successful with the specimen prepared by the ECAE after artificial aging whilst it was not successful with the specimen prepared by a reverse process sequence. The strength increase was confirmed by the tension and microhardness tests and compared to the result of conventional AA2024 bolt made by the conventionally heat treated specimen. It was found that the strength was comparable to the level of the heat treated conventional one although the actual value was a little bit lower. In addition, it was demonstrated that the heat treatment sequence is important to achieve proper formability of the ultra-fine grained material to manufacture the high strength bolt.

scholarly journals High Strength X3NiCoMoTi 18-9-5 Maraging Steel Prepared by Selective Laser Melting from Atomized Powder

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4174 ◽  
Author(s):  
Angelina Strakosova ◽  
Jiří Kubásek ◽  
Alena Michalcová ◽  
Filip Průša ◽  
Dalibor Vojtěch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Maraging Steel ◽  
Selective Laser Melting ◽  
High Strength ◽  
Industrial Applications ◽  
Tensile Yield Strength ◽  
Laser Melting ◽  
Maraging Steels ◽  
3D Printed

Maraging steels are generally characterized by excellent mechanical properties, which make them ideal for various industrial applications. The application field can be further extended by using selective laser melting (SLM) for additive manufacturing of shape complicated products. However, the final mechanical properties are strongly related to the microstructure conditions. The present work studies the effect of heat treatment on the microstructure and mechanical properties of 3D printed samples prepared from powder of high-strength X3NiCoMoTi 18-9-5 maraging steel. It was found that the as-printed material had quite low mechanical properties. After sufficient heat treatment, the hardness of the material increased from 350 to 620 HV0.1 and the tensile yield strength increased from 1000 MPa up to 2000 MPa. In addition, 3% ductility was maintained. This behavior was primarily affected by strong precipitation during processing.

Heat Treatment of High-Strength 3D-Printed Maraging Steel

2020 ◽  
Vol 403 ◽  
pp. 67-73
Author(s):  
Angelina Strakosova ◽  
Dalibor Vojtech ◽  
Drahomír Dvorský
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Maraging Steel ◽  
Precipitation Hardening ◽  
High Strength ◽  
Solution Annealing ◽  
Laser Melting ◽  
Maraging Steels ◽  
Final Microstructure ◽  
3D Printed

Maraging steels are interesting for research after heat treatment, from which name is derived "maraging" – martensite-aging. After solution annealing and precipitation hardening the X3NiMoCoTi 18-9-5 alloy has excellent mechanical properties (tensile strength reaches up to 2000 MPa and hardness is 50-55 HRC), it is ductile and well weldable. The advantage of these materials is the possibility to be manufactured not only by conventional methods but also by modern additive manufacturing (AM) methods. One of which is selective laser melting (SLM). In this paper, the influence of heat treatment on the final microstructure and mechanical properties of the 3D-printed X3NiMoCoTi 18-9-5 maraging steel is investigated.

scholarly journals Ballistic impact resistance of additive manufactured high-strength maraging steel: An experimental study

2021 ◽  
pp. 204141962110354
Author(s):  
Miguel Costas ◽  
Maisie Edwards-Mowforth ◽  
Martin Kristoffersen ◽  
Filipe Teixeira-Dias ◽  
Vegard Brøtan ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Maraging Steel ◽  
Impact Resistance ◽  
Low Carbon Steel ◽  
Hard Core ◽  
High Strength ◽  
Low Carbon ◽  
Ballistic Performance ◽  
Heat Treated ◽  
Ballistic Protection

Maraging steel is a low carbon steel known for its ultra high-strength after heat treatment. In combination with Additive Manufacturing (AM), the properties of maraging steel indicate potential to enable complex geometries and improved performance-to-weight ratios for ballistic protection. This study investigates the ballistic performance of AM maraging steel monolithic plates and profile panels fabricated by powder bed fusion. The mechanical properties of the maraging steel, both in the as-built state and after heat treatment, were revealed through quasi-static and dynamic tests in three different directions with respect to the build direction. Metallurgical studies were also conducted to investigate the microstructure of the material both before and after testing. The ballistic perforation resistance of the maraging steel samples was disclosed in a ballistic range by firing 7.62 mm APM2 bullets towards the different target configurations. Ballistic limit curves and velocities were obtained, demonstrating that the thickest heat-treated AM maraging steel plate has a particularly good potential for ballistic protection. The hard core of the armour piercing bullet broke in all tests and occasionally shattered during tests with heat-treated targets. However, due to the severe brittleness of the material, the targets showed significant fragmentation in some cases and most significantly for the profile panels.

Microstructure of resistance spot welding of maraging steels

1990 ◽  
Vol 48 (4) ◽  
pp. 900-901
Author(s):  
I. Neuman ◽  
S.F. Dirnfeld ◽  
I. Minkoff
Keyword(s):  
Maraging Steel ◽  
Spot Welding ◽  
Lath Martensite ◽  
Base Material ◽  
Aging Treatment ◽  
High Strength ◽  
Maraging Steels ◽  
Heat Treated ◽  
Current Cycle ◽  
Welding Processes

Experimental work on the spot welding of Maraging Steels revealed a surprisingly low level of strength - both in the as welded and in aged conditions. This appeared unusual since in the welding of these materials by other welding processes (TIG,MIG) the strength level is almost that of the base material. The maraging steel C250 investigated had the composition: 18wt%Ni, 8wt%Co, 5wt%Mo and additions of Al and Ti. It has a nominal tensile strength of 250 KSI. The heat treated structure of maraging steel is lath martensite the final high strength is reached by aging treatment at 485°C for 3-4 hours. During the aging process precipitation takes place of Ni3Mo and Ni3Ti and an ordered solid solution containing Co is formed.Three types of spot welding cycles were investigated: multi-pulse current cycle, bi-pulse cycle and single pulsle cycle. TIG welded samples were also tested for comparison.The microstructure investigations were carried out by SEM and EDS as well as by fractography. For multicycle spot welded maraging C250 (without aging), the dendrites start from the fusion line towards the nugget centre with an epitaxial growth region of various widths, as seen in Figure 1.

scholarly journals Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4366
Author(s):  
Saqib Anwar ◽  
Ateekh Ur Rehman ◽  
Yusuf Usmani ◽  
Ali M. Al-Samhan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Heat Affected Zone ◽  
Tensile Testing ◽  
Weld Zone ◽  
Alloy 800H ◽  
Weld Joints ◽  
Heat Treated ◽  
Friction Weld

This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.

Microstructure and Mechanical Properties of Ti-6Al-4V Manufactured by SLM

2015 ◽  
Vol 651-653 ◽  
pp. 677-682 ◽  
Author(s):  
Anatoliy Popovich ◽  
Vadim Sufiiarov ◽  
Evgenii Borisov ◽  
Igor Polozov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Phase Composition ◽  
Mechanical Behavior ◽  
Ductile Fracture ◽  
Elevated Temperatures ◽  
Initial Material ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Before And After

The article presents results of a study of phase composition and microstructure of initial material and samples obtained by selective laser melting of titanium-based alloy, as well as samples after heat treatment. The effect of heat treatment on microstructure and mechanical properties of specimens was shown. It was studied mechanical behavior of manufactured specimens before and after heat treatment at room and elevated temperatures as well. The heat treatment allows obtaining sufficient mechanical properties of material at room and elevated temperatures such as increase in ductility of material. The fractography of samples showed that they feature ductile fracture with brittle elements.

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