Spray forming

About: Spray forming is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 12869 citations. The topic is also known as: spray casting & spray deposition.

High corrosion resistance spray forming zinc-aluminum alloy and preparation method thereof

Abstract: The present invention provides a high corrosion resistance spray forming zinc-aluminum alloy and a preparation method thereof, belongs to the technical field of material preparation, and relates to a preparation process for a spray forming zinc-aluminum alloy The high corrosion resistance spray forming zinc-aluminum alloy is characterized in that when a spray forming technology is adopted to prepare a Zn-(25-35%)Al-(08-15%)Cu alloy, Cu element can be subjected to complete solid solution in Al and Zn so as to reduce a potential difference between the Zn phase and the Al phase and improve corrosion resistance of the alloy, wherein attached figures in an abstract comprise (a) a polarization curve of an ordinary casting Zn-30Al-1Cu alloy and (b) a polarization curve of a spray forming Zn-30Al-1Cu alloy

Experimental Study of Liquid Spray Mode of Twin Fluid Atomizer Using Optical Diagnostic Tool

Abstract: Twin fluid atomizers allow for two different spray forming modes, flow focusing and flow blurring, depending on the operating, geometric, and thermophysical properties of the working liquids. In flow focusing mode, the liquid jet breaks outside the injector, whereas in flow blurring mode, the liquid jet breaks inside the atomizer. Operating conditions are believed to play an essential role in determining the size and velocity of droplets with specific geometric and fluid properties. This work investigates the effect of air flow rate and liquid flow rate on spray characteristics by varying them independently. The geometric parameters, height (H = 0.3 mm) and orifice diameter (D = 1.5 mm) of the atomizer are kept constant (with H/D = 0.2). Spray mode is identified using high-speed images. Phase Doppler particle analyzer is used to measure droplet size and velocity simultaneously. Regardless of liquid flow rate, flow focusing mode is observed at low air flow rate and flow blurring mode is observed at high air flow rate. In general, flow blurring mode produced smaller droplets at higher velocities than flow focusing mode. The Joint probability distribution function of droplet size and velocity shows unimodal near the exit of the atomizer and bimodal distribution around 50 mm downstream due to the completion of the secondary breakup around that position and the subsequent loss of momentum due to the resistance of the surrounding air from the injector outlet. Flow focusing mode showed that sauter mean diameter and mass median diameter tend to increase initially due to coalescence of the spray and begin to decrease due to secondary breakup. The joint probability distribution of droplet Weber number and the droplet Reynolds number indicate that the flow blurring spray produced finer and faster droplets than the flow focusing spray. Overlapping of two Gaussians representing smaller and larger droplets best fits the droplet probability distribution as compared to lognormal or gamma or beta distribution.

Spray-Formed Stainless Steel Matrix Composites with Co-Injected Carbide Particles

Abstract: In order to develop new types of wear-resistant and corrosion-resistant materials, TiC and VC particles were injected into martensitic stainless steel X46Cr13 during spray forming, respectively. The microstructures of the spray-formed steel matrix composites under different processing conditions were investigated. The mechanisms of interactions between the injected particles and the matrix materials during spray forming and their effects on the microstructures of the composites were discussed and clarified based on experimental and theoretical investigations. The current results show that the injected particles may penetrate into the metallic droplets or adhere to the surface of the droplets and, therefore, are incorporated into the deposits to form metal matrix composites. Substantial heat transfer from superheated metallic melts to the room temperature carbide particles takes place as they are incorporated into the matrix material. The matrix steel solidifies in the vicinity of the carbides due to their chilling effect, and thus, the carbides may be engulfed in the matrix or pushed to the grain boundaries by the solidification fronts. TiC particles essentially retain their shape and size in the steel composites, while VC particles dissolve at least partially in the matrix and reprecipitate or form new phases in the final solidification and cooling stage. The porosity in the deposits increases with the gas to melt ratio (GMR) and the powder to melt ratio (PMR) by increasing atomizing gas pressure and powder feeding rate. Carbide type also affects the porosity of the deposits, because different thermodynamic properties of carbides change the heat dissipation and local solidification behavior of the mixture of matrix material and dissolved carbides. Moreover, the microstructure of the matrix material X46Cr13 is refined considerably with increasing GMR and PMR.

Modeling the Heat Flow in Spray Formed Steel Shells for Tooling Applications

Abstract: This article concerns a metal spraying process for the manufacture of production tooling at reduced time and cost. Critical to the successful operation of this process is control of the sprayed steel shell temperature to eliminate thermal residual stresses and distortion. A computational model of the transient heat flow in steel shells during spray forming has been developed. The critical data for the distribution of convective heat-transfer coefficient distribution over the shell surface and average spray temperature has been obtained from experiments using embedded calorimeters and process monitoring respectively. Shell average temperature and temperature variance have been investigated using the model, and predictions compared well with experimental measurements obtained using infrared thermal imaging. The wire feed rate was identified as the most suitable control parameter for a closed loop control system to regulate shell surface temperature during manufacture.

Spray formed articles made of boron steel and method for making the same

Abstract: The present invention relates to a method of spray forming a boron steel metal article, and to the formed article In at least one embodiment, the method comprises (a) providing a spray forming pattern, (b) spraying metallic particles onto the spray forming pattern, and (c) allowing the sprayed metallic particles to cool to form a metal article In at least one embodiment, the metallic particles are sprayed from a carbon steel feedstock having a boron content of 025-225 weight percent, based on the total weight of the feedstock