Aluminum Die Casting Defects No Defects Main cause 1 Short Fill 1.Metal is frozen before the cavity is filled or by insufficient metal being ladled. 2.Metal can cool down too much in the shot sleeve. 3.Some part of the die may be too cold 2 Cold Shut 1.Metal is frozen when two metal fronts join 2.Metal may be losing too much heat in the runner and cavity. 3 Scaling Layers of metal and oxides can be created by poor shot end control and /or bad gate and runner design 4 Blister Trapped gases are in the casting when the die is opened when the casting is still weak. This allows the compressed gas to expend and cause a blister. 5 Flash Metal pressure is too high upon the projected surface area (facing the platens ) of the casting at the end of cavity fill. This creates a force across the parting line which is too great for the clamping force of the machine. The die is then forced apart which allows metal escape. 6 Cold Flakes Metal is allowed to cool too much in the shot sleeve. The solid particles are then injected into the cavity. These flakes are often clearly visible on the surface of the casting with the naked eye 7 Shot Lube Stain This defect occurs when too much shot (tip) lube is used 8 Air Porosity This defect is caused by trapped air in the casting which can come from several sources. It can be caused by poor shot end control, poor venting and overflow function or bad gating and runner design. 9 Drag Marks Insufficient draft or an undercut causing a casting to be damaged on the surface when it is ejected. This effect may be reduced by changing the temperature at which the casting is ejected. Poor surface finish of the die can be another cause. 10 Hot Tearling or crackig This defect is caused by metal shrinking during solidification while under tension. At the last place to solidify a tear or crack develops which can be seen at the surface. 11 Hot Shortness The composition of the alloy causes the metal to be too weak at high temperatures (after solidification ). This then can cause cracks in the surface of the casting to appear in regions of high stress when the casting is cooling (and contracting ). NOTE: This defect can occur in conjunction with hot cracking. 12 Sink A sink is caused by a shrinkage cavity being near the surface of the casting. This causes the surface of the casting to collapse into the cavity as solidification occurs. Sinks are caused be the same things as shrinkage porosity as well as very poor thermal control of the die because hot spots are required for sinks to form. 13 Exploded Metal A combination of porosity and the casting being ejected before it has solidified completely. This allows the trapped gases to burst out of the casting along with any unsolidified metal. 14 Warpage A casting can deform after ejection during the time it is cooling down to room temperature. The root cause can sometimes be the casting geometry or the alloy specification. Warping can be minimized by ejecting at a lower temperature. Uneven die temperature is a major cause of this type of defect. 15 Soldering Chemical attack and bonding of aluminium to die steel. This causes aluminium to be torn away from the casting during ejection soldering can be reduced by a change in alloy and/or a reduction in die/metal temperature. 16 Shrinkage Porosity This defect is caused by metal reducing its volume during solidification and an inability to feed shrinkage with more metal before solidification. Hot spots can also cause shrinkage porosity to be concentrated in a specific zone. See ‘sink’ 17 Heat Checking This defect is caused by the surface of the tool steel continually expanding &contracting during use. Excessively cold dies &die flexing accelerate this effect. 18 Leaker Causes of leaks in castings where pressure tightness is required can be oxide folds and/or inclusions and/or porosity in conjunction with a surface defect which completes the path for a leak. A close analysis of the leaking area may reveal which of the many causes is causing the leak. 19 Discoloured Surface Oxide films (dross) and/or residues in the cavity and/or particles in the metal and/or excess die lube can cause the surface to be discoloured. Also it can be caused by a part of the die being too cold causing the casting to have darker regions or ‘smears’ on the surface. 20 Break Out Metal flakes(cold flakes) which get caught in the gate during cavity fill can break out unevenly when the casting is trimmed. 21 Inclusions The main causes of this type of defect are dirty/contaminated metal and/or poor melt banding practice. 22 Ejector Damage In broad terms, it can be defined as excessive pressure on the casting surface by the ejector pin(s) during ejection. 23 Erosion or cavitation Erosion is caused by direct molten metal impingment on die steel. Cavitation type erosion is caused by turbulence which causes low pressure regions in the flowing metal. These low pressure regions cause voids to form which can collapse at the die surface &cause erosion. 24 Craked Casting A crack in the casting can be caused by mechanical damage when the die is opened or when the casting is ejected. This classification excludes HOT CRACKING &cracking at the surface due to SHRINKAGE POROSITY. Also, this definition excludes HOT SHORTNESS. China die casting manufacturer, China aluminum alloy die casting factory, China zinc die casting components, China aluminum die casting parts, China Guokun Machinery to supply you the die casting, investment casting, sand casting, steel investment casting, iron sand casting, ductile iron sand casting, gray iron sand casting, etc Please send the RFQ to gina@guokuncasting.com or gina.guokun@gmail.com
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Casting Acceptance Report
Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shapes, and then allowed to solidify with complex shapes, such as pistons, mill rolls, wheels, cylinder blocks, liners, pipe fittings, elbow, etc The casting process can save much more metal, improve the production efficiency, expecially the investment casting or precision casting, can meet the accuracy without precision machining which can greatly reduce the production time. The steel casting, iron casting, aluminum casting, brass casting, bronze casting, copper casting which produced by Guokun Machinery or Guokun Casting, can save all requirements for various industry. The Acceptance Standard of casting parts are carried out as per customer’s requirements or the international standard & domestic standard. The Acceptance report are as follows: 1)The chemical compostion of material, such as gray iron casting, ductile iron casting, carbon steel investment casting, alloy steel precision casting, stainless steel silica sol casting, brass sand casting, zinc die casting, aluminum die casting, etc 2)The mechanical properties of casting, yield strength, tensile strength, hardness, elongation 3) The metallographic requirements of casting, carbide content, pearlite conent, graphite state, graphite length and so on, etc 4)The dimension of casting, must reach every dimension and accuracy or casting tolerance. 5)Casting Performance, such as leakage testing, hardness test, hydraulic testing, bending test, etc China steel casting parts, China iron casting components, China iron sand casting, China steel lost wax casting manufacturer, supplier, foundry, factory
Casting Impregnation
Casting Impregnation Casting impregnation is the process of removing air from the pores of leakage paths in a casting and replacing it with resin that is specifically formulated to cure in the pores so that the casting becomes pressure tight. The casting impregnation for die casting, investment casting, sand casting is a method of sealing porous materials without impacting the functional or dimensional characteristics of the material. Casting impregnation is important because when parts are created by casting metal, tiny defects are nearly impossible to avoid. Whether those defects involve porosity of the surface, bubbles or other types of incursions, they can negatively impact a part’s performance under operating conditions. Application of impregnation: zinc alloy casting, brass casting parts, aluminum casting components, iron castings, steel castings, such as engine block, cylinder head, intake manifold, oil pump, grease nipple, water pump, bonnet, cast oil pan, carburetor housing, gearbox housing, crankcase, Controller, power steering, automotive wheels, fuel pumps, natural gas control valves, hydraulic valves, cooling pumps, sealed aircraft equipment, and electronic equipment shields, gas brake parts and a variety of gas instruments. These castings are permanently sealed by infiltration into the micropores, and their pressure capacity reaches the bursting strength of the castings. Vacuum pump is the effective method to solve the casting impregnation which has the permanent and reliable sealing capacity on the casting with microporous holes. China sand casting manufacturer, China die casting factory, China investment casting foundry, China steel casting supplier, China iron casting exporter, pipe fittings, auto casting parts, agricultural casting parts, municipal engineering, oil & gas parts, train or truck parts, valve & pipe fittings, please send the drawings to gina@guokuncasting.com or gina.guokun@gmail.com
Casting Deformation and its Correction
Deformation process are frequentky occured during casting process, such as sand casting, investment casting, lost wax casting, precision casting, shell mold casting, die casting, steel casting, iron casting, hot forging, heavy forging, mold forging, free forging, which is result of casting stress. The casting stress caused during cooling process, if higher than yield strength, the casting will be deformed; if higher than tensile strength, there will be some cracks on the casting parts. During casting parts’s production, we try our best o eliminate stress via reasonable design. Generally, the casting deformation can be corrected by heat treatment. Usually the residual stress of the casting parts is often eliminated by natural againg or artifical againg, to ensure the quality. China sand casting manufacturer, China investment casting manufacturer, China lost wax casting foundry, China die casting factory, ductile iron sand casting, gray iron casting, alloy steel investment casting, carbon steel precision casting, stainless steel casting parts, if need, please send the drawings to gina@guokuncasting.com or gina.guokun@gmail.com
The Difference of Aluminum Ingots and Aluminum Alloy Ingots
The difference of aluminum ingots and alumnium alloy ingots Aluminum as a metal material, due to its own characteristies, such as beautiful, light-weight, corrosion resistance and other advantages. It is widely favored by the customers, especially the automotive industry which has been widely used. Aluminum ingots Aluminum or aluminium is a chemical element in the boron group with symbol Al and atomic number 13. Aluminum is remarkable for the metal’s low density and its ability to resist corrosion through the phenomenon of passivation, which are vital to the aerospace industry and important in transportation and structures. The pure aluminum ingots with high purity (99.7%) of aluminum can not meet the needs of industrial requirements, because of the no good physical performance. Aluminum Alloy Ingots Aluminum alloys are alloys in which aluminum is the predomiant metal. The typical alloying elements are copper, magnesium, managanese, silicon, tin and zinc, to improve the physical properties. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. The normal aluminum alloy we use are 6061, 6063, 6082, 7075, 356, 380, A380, etc If need the aluminum die casting, aluminum sand casting, aluminum alloy precision machining components, aluminum alloy die casting parts, please contact with Baoding Guokun Machinery, China aluminum alloy casting manufacturer, gina@guokuncasting.com or gina.guokun@gmail.com