Experimental casting of forging ingots from model material

The paper describes the process of casting ingots from the model material into a special mold made for these tests. The material was chosen stearin, which proved to be suitable for this type of laboratory test. During the solidification process of the ingot model under laboratory conditions, it was observed how gradually the layer formed on the contour of the casting. Gradual cooling of the ingot resulted in a decrease in the volume of the liquid phase in his body. The fog is readily observable by the naked eye and this is manifested by the formation of a gap between the ingot mold wall and the ingot body. A silicone oil has been used as a separating melt separating layer and the wall of the ingot that has reliably fulfilled this task. Casting was done in two ways, with a standing and lagging mold. The process of filling the cavity itself was to create conditions for the linear flow of the melt. Observation of the ingot after its solidification confirmed the fact that the filling of the cavity proceeded under such conditions in terms of the melt flow rate.

The Mathematical Model Applied to Solidify and Segregation of Ledeburite Tool Steel Ingots

In order to determine the optimum geometry of the ingot mold format (the format of ingot mold with a diameter per height ratio H / D <3 and the conicity of minimum 7%) was analyzed by mathematical modeling of solidification and segregation of the carbon and sulfur in it.It was considered 205Cr115 steel type (according with , STAS 3611 - Romanian stardandization) and known also as X210Cr12 steel type (according with European standard). It has been considered an element of volume of coordinates x, y, z in the solidifying ingot and have made the following assumptions: (i) the equilibrium distribution ratio K, is applied to the solid-liquid interface; (ii) solid diffusion is negligible during solidification; and (iii) the solid density is constant during solidification. In carrying out the simulation of segregation mechanisms are resolved heat transfer equation, that simulating the solidification process and are are solved the interdendritic fluid equation of motion.

Effects of the Processing on Mechanical Properties of High-Strength Structural Steel HG785D

The steel ingots of high-strength structural steel HG785D were produced by using a special water-cooled copper ingot mold. It analyzed the reason of the slab to achieve rapid solidification and shrinkage reducing with the simulation by using AnyCasting software. The difference properties between 100mm and 240mm steel plate with the same components were studied. The results show that properties are better with the increasing of the compression ratio, the times of TMCP and the reduction. The properties of 240mm steel plate with different composition were studied under the same heat treatment condition. Niobium, vanadium and titanium are in favor of the mechanical properties, but have little effect on the plasticity of structural steel. It should increase the harden ability of the alloy elements to improve mechanical properties of the steel HG785D.

Mathematical Modeling of the Mold Current and Its Influence on Slag and Ingot Behavior during ESR

ElectroSlag Remelting (ESR) is widely used to produce high added value alloys for critical applications (aerospace industry, nuclear plants, etc.). In collaboration with Aubert & Duval, Institut Jean Lamour has been developing for several years a numerical transient model of an ESR heat. In the previous version of the model, the crucible was assumed to be perfectly electrically insulated from the electrode-slag-ingot system. However, this assumption must be challenged: the solidified slag skin at the slag/mold and ingot/mold interfaces may actually allow a fraction of the melting current to reach the crucible. In this paper, an evolution of the model is presented that enabled us to take into account the possibility of mold current. The simulation results were compared with actual experimental data. Sensitivity studies showed the influence of slag properties and operating parameters on the final quality of the ingot. Results highlighted that even a weakly conductive solidified slag skin at the inner surface of the model can be responsible for a non-negligible amount of current circulating between the slag and crucible, which modifies the fluid flow, heat transfer and solidification of both the slag phase and the metallic ingot.

Numerical Simulation of Air Gap Formation in Water-Cooled Mold Casting

While using water cooled mold to produce steel ingot, an air gap is generated between the ingot and the mold, which has an important influence on the ingot quality. The air gap formation law and its influence on the solidification process were calculated by used FE software Procast. It is shown that, air gap occurs in a few minutes after the solidification begins. In 75-100s later the gap reaches 0.2-0.5 mm and starts to influent the heat transport significantly, the rate of the temperature decrease becomes slower. When the solidification is finished, there is a lager gap on the two narrow surfaces than it on the other wide surfaces; and the gap on the two narrow surfaces is different. The air gap on the narrow surface close to the sprue has a width of 12-20 mm; on the other narrow surface away from the sprue has a width of 4-13 mm. The biggest gap on the two wide surfaces has a size about 6.5mm. For the air gap is formatted between the ingot shell and the ingot mold, the solidification time is 50% longer than that of without air gap.

An Integrated AHP-Entropy Approach for Spare Parts Supplier Evaluation and Order Quantity Allocation

This paper employs a two-stage method to the spare parts supplier evaluation problem and the order quantity allocation problem. In the first stage, we integrated approaches of analytic hierarchy process (AHP) and information entropy to evaluate the suppliers. In the second stage, the alternative suppliers’ weight scores obtained in the first stage are used as coefficients of the objective functions in a linear programming model. The model is developed to determine the optimal order quantity from the suppliers with consideration of the suppliers’ capacities and the buyer’s quality requirements of the products and service. A numerical example about the typical spare parts - ingot mold purchasing in an iron & steel company is presented to illustrate the approach proposed finally