Ductile casting on a large cast iron platform is actually a casting processing process, and now all use earth magnesium alloy as nodularizing agent, and the iron furnace is the same as gray iron. In order to ensure good spheroidization, it is necessary to control the sulfur and some more. Taking into account the loss of temperature during incubation, the temperature of the molten iron on a large cast iron platform should be higher than that of gray iron. According to the grade of ductile iron produced, sometimes it is necessary to control the carbon content, and it is necessary to make a inoculated molten iron ladle to be added to the charge
Take a small spoon, a triangular specimen and a cylindrical specimen mold. There are a number of steel scraps and straw ash on the lathe. Stir the molten iron with a stirring rod (rebar wrapped in graphite or toner at the head. Before the furnace is opened, the soil alloy, ferrosilicon, ferromanganese and other alloy components required by the product are smashed into small pieces with a particle size of about 15mm. By the amount required for each pack of molten iron.
In order to solidify the investment casting sequentially and facilitate shrinkage, the inner runner is set at the thickness of the casting. This is the heat distribution on the large cast iron platform, resulting in a large temperature gradient, and the shrinkage of the casting is very inconsistent, which is easy to cause thermal cracks. This requires changing the position of the sprue so that the casting changes from sequential solidification to simultaneous solidification at a uniform temperature and consistent condensation, which can reduce or prevent the formation of thermal cracks on large cast iron platforms. Doing so may reduce thermal cracks in large cast iron platforms, but may cause cratering and porosity in large cast iron platforms.
In addition, the shape of the large cast iron platform is insufficient, and the liquid phase residue will block the coating layer, so that the pyrolysis gas discharge is blocked, the fluidity of the cavity is reduced, and the solidification is fast. Poor air permeability or insufficient negative pressure of the coating, poor air permeability of the sand, can not timely remove the gas and residue in the cavity of the large cast iron platform, the formation of pores under the filling pressure, the hot melt adhesive or cold glue bonded by the large cast iron platform pattern, in the case of ensuring that the stickiness, the less the dosage, the better. Try to avoid using slow vaporizing glue.
When the large cast iron platform is beating, dozens of molds can not be beaten, and it is necessary to wait for a few minutes before continuing to beat, to see if there are bright spots in the large cast iron platform material, if it is all cross-sectional gray plugging, the nozzle temperature can be moderately increased, and the time of hitting the nozzle is lowered by 01 to 0In 2 seconds, the cold water of the large cast iron platform is slightly turned off.
The large cast iron platform has high bearing capacity and stable rigidity, and its five sides are machined with regular holes and engraved with network cables. The large cast iron platform can be easily extended and expanded, combined. The extended standard table top can be directly joined together modularly and clamped. In the process of installing a large cast iron platform, adjusting and working pieces, the general functions of the large cast iron platform will be demonstrated, especially under the action of the concentrated load of about 2 about 1m2 in the large workpiece, and the deformation of the large cast iron platform does not exceed 050mm, the correct selection of large-scale cast iron platform sand mixing equipment has a great impact on the performance of resin sand, the requirements for the sand mixer are quantitative accuracy, uniform mixing, and good film coating effect of large-scale cast iron platform, and also consider the amount of large-scale cast iron platform, maintenance and product price. The design principle of the transformation of the large-scale cast iron platform: the production line should be less and the structure should be compact. The main engine of the equipment should be selected according to the economic strength of the production plant. To be less, the auxiliary union tries to prepare it by itself. The resin sand production line of the large-scale cast iron platform mainly includes a sand mixing molding system and a sand removal system.
Prevent the nitride layer on the surface from being damaged, and the more you throw it, the more sticky it becomes. Improve the design structure of the gating system to avoid the continuous erosion of the cavity wall or core by the molten alloy. Modify the mold cooling system for large cast iron platforms. Adjust the process parameters of the riveting and welding platform, appropriately reduce the injection speed, and shorten the two-speed stroke. How to improve the nodularization rate of a large cast iron platform for ball milling.
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