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What items and alloys can be Impregnated? |
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All ferrous and nonferrous metals can be Impregnated to fill porosity. Iron. Bronze, Aluminium, Zinc, Magnesium, Steel, Sintered powder metallurgy products and plastics and alloys of the metal can be Impregnated. Sand castings, gravity and pressure die cast components and forgings can be Impregnated to seal porosities and ensure pressure tightness, A wide range of components typically area. Vacuum Impregnation using AB 707 can be used to effectively seal such assemblies. |
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Entrapping contaminants : |
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Contaminants that are absorbed into the porosity during manufacturing operations can later bleed out in service and effect the clean operation of moving parts. The Aswin's vacuum Impregnation process will prevent these contaminants from being drawn out into air and liquid control systems, thereby blocking pumps and filters. |
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A new dimension to casting design : |
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The heavy thinkers in the metal industry are looking to the future and thinking lighter everyday. Use of light weight cast metals, most notably Aluminium and Magnesium have opened by all doors for the development engineers. |
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Explain the principle of vacuum Impregnation? |
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By applying a vacuum of under 5 mbar the air trapped in the porosities is withdrawn, By the vacuum effect the sealant penetrates into the porosities. After the vacuum has been released, the sealant is pressed by the atmospheric pressure into the porosities and in that manner reaches the finest porosities. In the water bath the components surface is washed so no surface film remains. No additional washing is required afterwards. Curing of the Imp regnant in the polymerizing bath at 90deg C. By this method there is no exudation of the acrylic resin contained in the porosities. |
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What pressure tightness can be achieved? |
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Pressure tightness upto 10000 psi(3000kg/Cm2)can be achieved by using IM-3000 sealant. |
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What service temperature ranges are applicable for Impregnated components? |
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Components intended for constant and continuous service temperature from 50deg C and 220deg C can easily be Impregnated with Special Sealant. For air or water cooled components like automotive cylinder heads or for components of rockets and missiles where very short term heating is involved temperatures upto 750deg C can be withstood for short and intermittent periods using sealants. |
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| Impregnation FAQ |
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When should the Impregnation be carried out before or after machining? |
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Machining will open up interconnected and subsurface porosity, Normally, therefore it is preferable to do it after machining, unless the castings are subjected to pressure test in the as cast stage itself. Furthermore, very often, the decision as to whether to Impregnate before or after Impregnation would also depend upon the history of the casting and also whether the casting leaks from the raw and unmachined areas. |
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If the casting is subjected to vibration, will the Impregnated material come out? |
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No. AB 707 is formulated in such a way that it has high strength and it is not brittle. The sealant is locked inside the pore and will remain so far as the life of the casting. |
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How Impregnation is useful for electroplating? |
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Bleed out and blistering are problems in lacquer and baked enabel finishes. To avoid these Impregnation is resorted to before Electroplating Porous areas absorb electrolyte and cause bleed out and acid etches. Impregnation seals the pores and produces an uniform coating. |
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Can a cracked component be salvaged by Impregnation? |
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No. Cracked component will have to be salvaged by welding or other means. Impregnation is not the solution here. |
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What is the use of Impregnation for powder metallurgy or sintered components. |
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Sealing of porosity prevents corrosion and fungus growth. Also, Sintered components that need to undergo electroplating must be Impregnation prior to the plating operation. |
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Will Impregnation lead to discoloration? |
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No. A good quality sealant will not cause discoloration. Of cause AB 707 will not cause discoloration at all. |
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Will Impregnation will cause distortion or degradation of mechanical properties in my casting? |
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No. That is why we have kept ouring temperature at 90 deg C. No distortion or degradation of mechanical properties takes place by using AB 707. |
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Will the tapped holes get damaged or closed with residue during Impregnation? |
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No. We follow special procedure to protect the tapped holes. Positioning of casting inside the work basket also needs special attention. Moreover, the excellent washability of IM-3000 further ensures that no residues are left behind |
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What is vacuum Impregnation? |
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Vacuum Impregnation is the process of sealing the porosity in castings. The Impregnation material, which is called "Special Sealant" is introduced into the porosity within the wall thickness of the casting through vacuum. The sealant liquid is subsequently silidified by heating at elevated temperature. The process is carried out using the Dry Wet Porosity Sealing Systems using the world renowned and approved Special Sealant AB 707 |
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Improving surface treatment : |
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Impregnation of castings, powder metal components and other porous rigid materials prevents the ingress of treatment acids into microporosity which would otherwise leach out and corrode the finished surface. Vacuum Impregnation using AB 707 is commonly used for the sealing of porosity prior to anodising. Powder paint coatings applied to casting and other porous materials are, likely to blister when stoved due to the expansion of air entrapped within porosity open to the surface. Impregnation in used to seal this porosity prior to painting and stoving to prevent this blistering. |
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Powder metal components : |
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These can be vacuum Impregnated using the Aswin's process after sintering to render them pressure tight. The ability to effectively vacuum Impregnated and seal powder metal components has allowed designers to incorporated these parts into water and oil pump seals, motor cylinders for pneumatic tool and other applications requiring 100% pressure tightness. |
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Sealing inserts into assembly : |
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Components containing inserts and sleeves can be vacuum Impregnated with both to seal the assembly for pressure tightness in addition to bonding the insert. Substantial saving can be made by employing batch Impregnation in place of the more labour intensive methods which use adhesive for bonding and sealing insert into assemblies |
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Brazed and Welded assembly : |
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Similar to casting dip brazing can contain microporosity and allow leakage of coolant fluids under pressure, as in heat exchangers. These assemblies are often difficult to seal locally because the cooling fins can prohibit access to the porous. |
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Impregnated with AB 707 sealant are |
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Aerospace components |
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Air compressors |
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Automotive cylinder heads and blocks |
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Electrical connectors |
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Food processing equipment |
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Filtration equipment |
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Fuel supply systems |
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Hydraulic pumps/valves |
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Process control equipment |
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Transmission housing |
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Wheels |
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Power brakes |
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Thin walled die castings |
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Powder metallurgy products |
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Electronic components |
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Gas and steam fittings |
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Plastic moulds |
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Instrumations meters and valves |
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Refrigeration components |
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Truck and railway brake parts |
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Cast row hydraulic control. |
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Ceramic parts |
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Builder's hardware |
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Aluminium compressor castings |
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Can I save money, time and energy by adopting Impregnation? |
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Yes when you send the Impregnated castings to your customer, the chance of it getting rejected at your customer's place due to a leakage is eliminated and you get quality assured. The Impregnation cost is only a very small fraction of the cost of remelting, remaking and other costs. In addition you save time and energy for recasting and machining. Moreover, the new casting that is made, may again turn out to be a leaker ! |
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When should Impregnation be carried out? Before or after machining? |
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Machining will open interporosity. Normally it is preferable to do it after machining unless the castings are subjected to pressure test in cast stage itself. Also, depending upon the history of the casting and also the areas of leakage, You can decide whether to Impregnate the raw casting or machined castings. |
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Is there any Indian standard for vacuum Impregnation? |
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Yes. Is 12799-1989 provides the Indian Standard for Foundry-Impregnation of castings recommended practice. |
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Is there any military standard recognized worldwide for this process? |
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MIL-STD-276 provides Military Standard on Impregnation of porous non ferrous metal castings. Furthermore the US MIL 17563 B is the most stringent standard in the world for Impregnation sealants. |
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