Effect of LCFeCr Alloy Additions on the Non-metallic Inclusion Characteristics in Ti-Containing Ferritic Stainless Steel

The influence of commercial low carbon ferrochromium (LCFeCr) additions on the inclusion characteristics in Ti-containing ferritic stainless steel was studied by laboratory experiment in this work. The inclusions in steel before and after the FeCr alloy additions were investigated through systematic samplings and microscopy investigations of the liquid steel. Different types of inclusions in the FeCr alloy and steel were detected and the evolution of the inclusion characteristics (e.g., composition, size, morphology, and number density) were investigated. The results showed that the Ti content decreased after the FeCr alloy additions. Furthermore, MnCr2O4 spinel inclusions originating from the FeCr alloys transformed into Ti2O3–Cr2O3-based liquid inclusions and Ti2O3-rich solid inclusions. They were formed due to the reactions between MnCr2O4 and TiN inclusions or dissolved Ti in molten steel. The ratio of Ti/Al in the steel melt has a direct influence on the evolution of inclusions from thermodynamic calculations. The addition of FeCr alloys caused an increased number density of these Ti2O3-containing inclusions and TiN inclusions up to 8 minutes from the time of alloy addition. The increased Cr content from 16 to 24 mass pct due to the FeCr additions can increase the critical N content to form TiN inclusions at a specific Ti content. Overall, this study has contributed to the understanding the behavior of inclusions from LCFeCr alloy during the alloying process in Ti-containing steel.

Titanium in Cast Cu-Sn Alloys—A Review

The article reviews the progress made on bronze alloys processed through various casting techniques, and focuses on enhancements in the microstructural characteristics, hardness, tensile properties, and tribological behaviour of Cu-Sn and Cu-Sn-Ti alloys. Copper and its alloys have found several applications in the fields of automobiles, marine and machine tools specifically for propellers in submarines, bearings, and bushings. It has also been reported that bronze alloys are especially used as an anti-wear and friction-reducing material to make high performance bearings for roller cone cock bits and warships for defence purposes. In these applications, properties like tensile strength, yield strength, fatigue strength, elongation, hardness, impact strength, wear resistance, and corrosion resistance are very important; however, these bronze alloys possess only moderate hardness, which results in low wear resistance, thereby limiting the application of these alloys in the automobile industry. The major factor that influences the properties of bronze alloys is the microstructure. Morphological changes in these bronze alloys are achieved through different manufacturing techniques, such as casting, heat treatment, and alloy addition, which enhance the mechanical, tribological, and corrosion characteristics. Alloying of Ti to cast Cu-Sn is very effective in changing the microstructure of bronze alloys. Reinforcing the bronze matrix with several ceramic particles and surface modifications also improves the properties of bronze alloys. The present article reviews the techniques involved in changing the microstructure and enhancing the mechanical and tribological behaviours of cast Cu-Sn and Cu-Sn-Ti alloys. Moreover, this article also reviews the industrial applications and future scope of these cast alloys in the automobile and marine industries.

Microstructure And Mechanical Properties of Ultrasonically Processed Al-7Si Alloy / Y2O3 Nanocomposite

The aim of the present study is to investigate the microstructure and mechanical properties of the A356 aluminum metal matrix composite reinforced with Y2O3 particles. The composite is synthesized by adding 1 and 2 vol.% of reinforcement via stir casting assisted by ultrasonic treatment (UT). Microstructural contemplates shows improvement in the dispersion of nano Y2O3 particles and decrease in the porosity level due to the ultrasound aided synthesis. The UT refines the size of the Y2O3 particles as well as helps to improve its dispersion. The secondary dendrite arm spacing of 2 vol.% Y2O3 reinforced samples with 5 min UT is found to be significantly reduced to 12 µm as compared to that of the as-cast A356 alloy. Addition of 2 vol.% of nano Y2O3 has significantly improved the hardness of the A356 alloy from 60 HV to 108 HV. A considerable increment in the YS and TS of the A356 alloy is observed with the of Y2O3 and found to further improve with UT. However, small reduction in ductility is observed with the addition of Y2O3 as well as ultrasonic treatment.

New Insight on Liquid Steel Microalloying by Pulse-Step Method in Two-Strand Slab Tundish by Numerical Simulations

Developing a technology for introducing alloy addition to liquid steel during the course of continuous casting process seems to be an interesting approach to enhancing the steelmaking process, especially as the effective introduction of micro-additives or non-metallic inclusion modifiers to the liquid steel is the key to the production of the highest-quality steel. This paper presents the results of investigation describing the process of liquid steel chemical homogenisation in the two-strand slab tundish. The alloy was fed to liquid steel by pulse-step method. Five tundish equipment variants with different flow control devices and alloy addition feeding positions were considered. The paper includes fields of liquid steel flow, alloy concentration vs. time curves, dimensionless mixing time, minimum time values and alloy concentration deviations at tundish outlets. The results pointed much more effectively with liquid steel mixing nickel than aluminium. For aluminium obtaining a 95% chemical homogenisation level requires three-fold more time. Moreover, it is definitely beneficial for chemical homogenisation to initiate the alloying process simultaneously in two sites. This procedure generates, among others, the least alloy deviation of concentration at tundish outlets.

Influence of Si Addition on the Microstructure and Mechanical Behaviour of Mg-5sn-3zn-1mn Alloy

The microstructural, mechanical behaviour of Mg-5Sn-3Zn-1Mn alloy with different Si additions (0.5, 1, 1.5 wt. % Si) are investigated and morphological changes of Mg-5Sn are observed with the addition of each element like 3Zn and 1Mn. Si added Mg-5Sn-3Zn-1Mn alloy exhibits two different phases namely Mg 2 Sn and Mg 2 Si. Two distinct phases observed are rod like Mg 2 Sn phase and Chinese script Mg 2 Si upto 1wt%. When Si addition exceeds 1.5% polygonal shaped primary Mg 2 Si particles are formed. In Mg-5Sn-3Zn-1Mn alloy addition of Si up to 1wt% enhances the mechanical properties adequately. Above 1 wt% of Si addition, a slight reduction on tensile property is noticed, which is due to the formation of hard, brittle polygonal primary and coarse Chinese script phases.

Development of Al–Mg–Si alloy performance by addition of grain refiner Al–5Ti–1B alloy

Aluminum alloys are the most essential part of all shaped castings manufactured, mainly in the automotive, food industry, and structural applications. There is little consensus as to the precise relationship between grain size after grain refinement and corrosion resistance; conflicting conclusions have been published showing that reduced grain size can decrease or increase corrosion resistance. The effect of Al–5Ti–1B grain refiner (GR alloy) with different percentages on the mechanical properties and corrosion behavior of Aluminum-magnesium-silicon alloy (Al–Mg–Si) was studied. The average grain size is determined according to the E112ASTM standard. The compressive test specimens were made as per ASTM: E8/E8M-16 standard to get their compressive properties. The bulk hardness using Vickers hardness testing machine at a load of 50 g. Electrochemical corrosion tests were carried out in 3.5 % NaCl solution using Autolab Potentiostat/Galvanostat (PGSTAT 30).The grain size of the Al–Mg–Si alloy was reduced from 82 to 46 µm by the addition of GR alloy. The morphology of α-Al dendrites changes from coarse dendritic structure to fine equiaxed grains due to the addition of GR alloy and segregation of Ti, which controls the growth of primary α-Al. In addition, the mechanical properties of the Al–Mg–Si alloy were improved by GR alloy addition. GR alloy addition to Al–Mg–Si alloy produced fine-grained structure and better hardness and compressive strength. The addition of GR alloy did not reveal any marked improvements in the corrosion properties of Al–Mg–Si alloy.

Iron Carbon Masteralloy as Sintering Activator for Low Alloy Powder Metallurgy Steels

In real industrial environment there is always a difference between ideal theoretical condition and real production condition which bears the risk of producing defective or low quality parts. Getting closer to this ideal situation requires more effort and investment which tends to increase the production cost. In the P/M production lines, the sintering stage is one of the most critical processes. Maintaining an open continuous sintering furnace in an ideal condition is a challenge, and this issue gets more pronounced when using alloy powder containing oxygen-sensitive elements such as Cr or Mn which provide good hardenability at low cost but on the other hand form stable oxides that weaken the sintering contacts if they are not reduced properly. In the present study, using a carbon master alloy as a sintering enhancer in the sintering process of Cr-Mo alloyed powder compacts has been investigated. For clearly depicting the effect of carbon master alloy addition on carbon dissolution and deoxidation, sintering was done in argon as inert atmosphere to avoid other reducing agents such as H2. The physical and mechanical properties of the sintered specimens were investigated, and thermal chemical analysis by DIL/MS and carbon/oxygen measurements were performed. The experiments showed that adding iron-carbon masteralloys promote the sintering processes such as reduction of oxides and carbon dissolution in the early stages of sintering, resulting in better properties after final sintering.

Development of Al-TiC Wire Feedstock for Additive Manufacturing by Metal Screw Extrusion

The development of customised aluminium alloys for welding and additive manufacturing (AM) is proposed to solve several quality issues and to enhance the mechanical integrity of components. The introduction of ceramic grain refining agents shows great potential as alloy addition as to limit cracking susceptibility and increase the strength. Thus, a versatile solid-state manufacturing route for nanoparticle reinforced aluminium wires has been developed based on the metal screw extrusion principle. In fact, the Al-Si alloy AA4043 mixed with 1 wt.% TiC nanoparticles has been manufactured as a wire. The accumulated strain on the material during metal screw extrusion has been estimated, classifying the process as a severe plastic deformation (SPD) method. A chemical reaction between silicon and TiC particles after metal screw extrusion was found, possibly limiting the grain refining effect. Electric arc bead-on-plate deposition was performed with metal screw extruded and commercial material. The addition of TiC induced a grain morphology transition from columnar to equiaxed after electric arc deposition, and increased the hardness. A high amount of porosity was found in the AA4043-TiC material, probably arising from hydrogen contamination on TiC surfaces prior to metal screw extrusion. The results are encouraging as a new direction for aluminium alloy development for additive manufacturing.

Nickel alloy addition impact upon structure of Al-10%TiC composite

In the paper there is considered the impact of nickel alloy addition upon the process of titanium carbide phase formation during the realization of self-propagating high-temperature synthesis in aluminum melt. The regularities of structure formation and optimum conditions for an engineering process for Al-4%Ni-10%TiC composite manufacturing are defined.

Influence of Porosity and Alloy addition on the Wear behaviour of a Sinter-Forged C45 Steel using Taguchi Method

Elemental powders of Atomized Iron (Fe), Carbon (C) and Molybdenum (Mo) were weighed and mixed in a pot mill to yield the composition of C45, C45-1%Mo and C45-2%Mo Steels, then compacted and sintered. The Sintered preforms had a density- 75% of the Theoretical Density. Then the Sintered preforms were subjected to densification to get two densities- 80% and 85% of the theoretical density through Forging. The sintered and densified preforms of alloy steels were subsequently machined to get the required wear test specimens.The experiments were conducted on a Pin-on-disc Tribometer, conforming to ASTM G99 standards, on a rotating EN32 disc. Using Minitab 16 software, the Dry Sliding wear experiments were planned using L27 Orthogonal Array.The % Theoretical Density of the Specimens (1-%Porosity), % Mo Addition, Load and Sliding Velocity were taken as input parameters, mass loss was the output parameter. It was observed that the increasing density of alloy steels adversely affects the wear resistance of the alloy steels and mass loss is increased. It was found that the addition of Mo significantly improves the wear resistance of the alloy steels irrespective of the densities .Empirical correlations for mass loss with respect to input parameters had been developed.