scholarly journals Evaluation of Strength and Microstructural Properties of Heat Treated High-Molybdenum Content Maraging Steel

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1446
Author(s):  
Asiful H. Seikh ◽  
Hossam Halfa ◽  
Mahmoud S. Soliman

Effect of high molybdenum content ~10% as an alloying element on the strength and microstructural properties of 11% nickel—1.25% titanium maraging steel was evaluated. To increase the homogeneity and cleanliness of produced ingot, the investigated steel sample was produced by melting the raw material in an open-air induction melting furnace followed by refining utilizing a direct current electro-slag refining machine. The produced steel samples were both forged and heat-treated in optimum condition to acquire the full capacity of mechanical properties especially the tensile properties. After Forging and heat treatment at optimum condition, steel samples were evaluated by optical microscopy (OM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) analysis, electron backscattering diffraction (EBSD), and transmission electron microscopy (TEM). The experimental data showed that this steel sample has ultimate strength ~2100 MPa and elongation around 14%. High tensile properties obtained may be attributed on one hand due to the presence of high alloying lamellar martensite phase and lamellar austenite phase which has high dislocation intensity, and on the other hand, due to the high homogeneity and cleanliness of investigated samples from large nonmetallic inclusions. The results also show that a high amount of intermetallic compounds (NiMo3 and NiTi3) which are completely round and have a very low size not more than hundred nanometers.

Author(s):  
Even W. Hovig ◽  
Amin S. Azar ◽  
Klas Solberg ◽  
Knut Sørby

AbstractIn order to explore the possibilities enabled by laser beam powder bed fusion of metals (PBF-LB/M), reliable material models are necessary to optimize designs with respect to weight and stiffness. Due to the unique processing conditions in PBF-LB/M, materials often develop a dominating microstructure that leads to anisotropic mechanical properties, and thus isotropic material models fail to account for the orientation-dependent mechanical properties. To investigate the anisotropy of 18Ni300 maraging steel, tensile specimens were built in seven different orientations. The specimens were heat treated at two different conditions and tested for their tensile properties using digital image correlation (DIC) technique. The microstructure and fracture surfaces are investigated with scanning electron microscope and electron backscatter diffraction. The tensile properties are typical for the material, with a yield strength in the range of 1850 MPa to 1950 MPa, and ultimate tensile strength in the range of 1900 MPa to 2000 MPa. The elastic modulus is 180 GPa, and the elongation at fracture is in the range of 2–6% for all specimens. The strain fields analysed with DIC reveals anisotropic straining in both the elastic and plastic parts of the flow curve for both direct ageing and solution treatment plus ageing specimens. In the former condition, the elastic anisotropy is dictated by the fraction of melt pool boundaries on the transverse surfaces of the specimens. When the material is solution treated prior to ageing, the melt pool boundary effect was supressed.


2021 ◽  
Author(s):  
Even Wilberg Hovig ◽  
Amin S Azar ◽  
Klas Solberg ◽  
Knut Sørby

Abstract In order to explore the possibilities enabled by laser beam powder bed fusion of metals (PBF-LB/M), reliable material models are necessary to optimize designs with respect to weight and stiffness. Due to the unique processing conditions in PBF-LB/M, materials often develop a dominating microstructure that leads to anisotropic mechanical properties, and thus isotropic material models fail to account for the orientation-dependent mechanical properties. To investigate the anisotropy of 18Ni300 maraging steel, tensile specimens were built in seven different orientations. The specimens were heat treated at two different conditions and tested for their tensile properties using digital image correlation (DIC) technique. The microstructure and fracture surfaces are investigated with scanning electron microscope and electron backscatter diffraction. The tensile properties are typical for the material, with a yield strength in the range of 1850 MPa to 1950 MPa, and ultimate tensile strength in the range of 1900 MPa to 2000 MPa. The elastic modulus is 180 GPa, and the elongation at fracture is in the range of 2-6% for all specimens. The strain fields analysed with DIC reveals anisotropic straining in both the elastic and plastic parts of the flow curve for both direct ageing and solution treatment plus ageing specimens. In the former condition, the elastic anisotropy is dictated by the fraction of melt pool boundaries on the transverse surfaces of the specimens. When the material is solution treated prior to ageing, the melt pool boundary effect was supressed.


Furnaces are most commonly used for melting of Ferrous Metals and its alloy materials. Induction furnaces use Electrical Power so that they are more advantageous as no fuel is required. It is a very critical problem to find life span of Induction Melting Furnace Wall under thermal load variation. The life cycle of induction furnace refractory wall is a variable as minor variation is always present due to effect of skill of workers and many other factors. The life cycle of furnace wall will vary minor with some miscellaneous factors and cannot be justified as a single value always. The probability concept is utilized here in the forecast of life cycle calculation to justify the miscellaneous factors effected for the damage of the induction furnace refractory wall. The probability concept initially defines a minimum life of induction furnace wall for a certain case then it is assumed to vary with different probability as given below. So, all the cases of induction furnace wall are having minimum life always but some cases of induction furnace wall are having much longer life. It is due to effect from many miscellaneous factors like skills of workers, efficiency of workers, raw material quality used for construction of wall, tools applied for ramming of it, row material employed for melting, etc.


2021 ◽  
Author(s):  
Shahid Hussain ABRO ◽  
Alidad CHANDIO ◽  
Asif Ahmed SHAIKH ◽  
Norbaizura NORDIN ◽  
Hamza SUHARWARDI

An attempt has been made in the present research work to investigate the role and influence of chemical effect of aluminum addition in the experimental steel towards the formation of k-carbides. Two steel grades were made with and without aluminum addition by induction melting furnace and were cast to ingots. Steel A has no aluminum addition and steel B has some aluminum content. These ingots were then solution heat treated on a temperature of 1200°C for 2-hours’ time and were cooled in the air. After that, they were hot rolled to drawn in plate and sheet. The small samples were cut from bulk and were then heat-treated at 800°C for 1 hour and quenched. Microstructure by OM and SEM was captured. In steel A there was no k-carbide present in the matrix and surprisingly in steel B, small fine k-carbides were present this was then confirmed by XRD later. OM, SEM, and TEM analysis revealed that the presence of k-carbides in steel B makes less dense. It was concluded that aluminum in conjunction with nitrogen forms the small nitride particles having a high melting point does not dissolve during the melting and casting such particles are known as AlN or aluminum nitride particles was observed by TEM along with EDS was the main reason to support the formation of k-carbides, these fine nano level k-carbides are orderly distributed in the steel matrix as was shown by XRD peaks.


Author(s):  
I. Neuman ◽  
S.F. Dirnfeld ◽  
I. Minkoff

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.


Alloy Digest ◽  
1991 ◽  
Vol 40 (7) ◽  

Abstract Allvac 718 is produced by vacuum induction melting followed by vacuum arc or electroslag consumable remelting. Th alloy has excellent strength and good ductility up to 1300 F (704 C). It also has excellent cryogenic properties. It has unique welding characteristics. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-394. Producer or source: Allvac Inc..


Alloy Digest ◽  
1990 ◽  
Vol 39 (11) ◽  

Abstract NICKEL VAC X-751 is a modification of NICKEL VAC X-750 carrying higher aluminum content (0.90-1.50 vs 0.4-1.0%). This raises the maximum service temperature 100 F(55 C) to 1600 F(871 C). NICKEL VAC X-751 has a simplified and shortened heat treating cycle relative to NICKEL VAC X-750. It is produced by vacuum induction melting followed by vacuum arc or electroslag remelting. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-387. Producer or source: Teledyne Allvac.


Alloy Digest ◽  
1988 ◽  
Vol 37 (1) ◽  

Abstract UNS No. A02080 is a heat-treatable casting alloy characterized by good castability, machinability and resistance to corrosion. It is produced by sand casting and is a general-purpose alloy recommended in both the as-cast and heat-treated conditions. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-286. Producer or source: Various aluminum companies.


Alloy Digest ◽  
2014 ◽  
Vol 63 (7) ◽  

Abstract BrushForm 96 strip is a high-performance, heat treatable spinodal copper-nickel-tin alloy designed to provide optimal formability and strength characteristics in conductive spring applications. It is available in both pre-heat treated (mill hardened) and heat treatable (age hardenable) forms. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. and bend strength. It also includes information on forming. Filing Code: Cu-833. Producer or source: Materion Brush Performance Alloys.


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