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1、铝合金铸棒缺陷的产生原因( Causes of defects in Aluminum AlloyCasting Bars )Classification of defects in aluminium and aluminium alloy ingotsName, fatal defect, serious defect, general defect, minor defectThe chemical composition does not agree with *Tissue burn *Slag inclusion * *Porosity and porosity * * *Crac
2、k *Size discrepancy * * *Metal compound *Laminated *Bright grain *Coarse grains * *NameLeukoplakiaBending *White dot *1. the chemical composition does not agree with each otherWhere the range of chemical composition of aluminum and aluminum alloy exceeds the national standard(GB/T3190-1996) provides
3、 that impurities higher than the ceiling, and affect the final performance of substandard products, are called chemical composition does not match, is an absolute waste.Causes1- the chemical composition of the ingot in the factory does not meet the technical requirements or has no technical qualific
4、ation certificate.The estimated percentage of waste and mixture weight in 2- blending is inaccurate.The 3- ingredient accurately matches the alloying elements of the alloy.The composition of 4- intermediate alloy is not qualified or fluctuates greatly.5- rapid analysis of specimens without represent
5、ation, laboratory, error analysis, or error analysis report.6- alloy transfer group does not wash furnace or washing furnace is not thorough.When the 7- is smelted, the burning is too large or the amount of burning loss is not accurate.8- metal melt in the furnace for a long time and burning, mixing
6、 components uneven sampling.2. layered defects:In the process of casting liquid metal melt, open mold has been solidified on the surface near the mold wall, the ingot surface formed on the two layer, called a layer (or cold isolation).This defect seriously damagedthe continuity of the whole ingot st
7、ructure, and should generally be waste products. If the car can be allowed to use completely disappear.Forming reason:1- casting speed is slow, the metal melt flow is insufficient, the edge is easy to solidify, the melt that continues to supply does not add up to solidify ahead of time;The casting t
8、emperature of 2- is low, the fluidity of molten metal is not good, and it is easy to solidify near the mould wall;The casting funnel of 3- is not placed properly, and the metal melt flows unevenly into the funnel;4- the funnel is blocked, the cooling in the condensate tank is uneven, and the metal i
9、s quickly solidified in the place where the cooling rate is great;5- lubrication uneven or partial oiling too much;6- casting stops halfway, suspension or metal melt flow, high and low;The taper in the 7- condenser tank does not meet the requirements.3. crack and stretch markAs the friction between
10、the outer surface of the ingot and the mould exceeds the strength of the ingot itself, a tensile mark is formed on the surface of the ingot, and the ingot is broken or broken in severe cases.This kind of defect seriously damaged the continuity of the whole ingot structure, and should be waste in ser
11、ious condition.If the car can be allowed to use completely disappear.Forming reason:1- mold internal surface is not smooth, burr, scratches, lubrication is not good;The 2- mould is produced by tilting and causing great resistance when the ingot is lowered;In the process of 3- casting, the metal body
12、 is high and low and causes suspension of the core (hollow ingot) or aluminum leakage;4- casting speed, casting temperature is high, casting water pressure is big, easy to cause crack or stretch mark4. slag inclusionMetal slag is customarily referred to as copper, iron and other metal fragments that
13、 occasionally fall into pieces;The non-metallic slag inclusion mainly refers to the slag inclusion on the low test piece, such as slag inclusion, slag and flux, asbestos plate and so on.Slag inclusion is divided into surface slag inclusion and internal slag inclusion.Slag inclusion damages the conti
14、nuity of ingot structure and seriously affects the quality of the products.Causes:1- raw and auxiliary materials are not clean, such as oil, dirt, dust, moisture and so on;In the process of 2- smelting, the surface oxide film has been destroyed manytimes because of repeated feeding, dilution and agi
15、tation;In the process of converting to 3- impact too much, not fullof molten metal flow or gap is too large due to oxidation slag;4- refining improper operation, refining is not sufficient, so that the refining effect is not good;5- in the casting process, the metal level fluctuates greatly, each fa
16、lls nearly to seal off, and the beginning and ending are improper;6- is affected by the nature of alloy. If some alloys are poor in fluidity, it is difficult to float slag;7- casting temperature is too low, slag is difficult to float5. oxide filmFragments of complex oxides consisting of metal aluminum and AI2O3 in oxidation in air and other oxides in alloy elements (s
