铝合金铸棒缺陷的产生原因(Causes of defects in Aluminum Alloy Casting Bars)

铝合金铸棒缺陷的产生原因（Causes of defects in Aluminum Alloy

Casting Bars）

Classification of defects in aluminium and aluminium alloy ingots

Name, fatal defect, serious defect, general defect, minor defect

The chemical composition does not agree with *

Tissue burn *

Slag inclusion * *

Porosity and porosity * * *

Crack *

Size discrepancy * * *

Metal compound *

Laminated *

Bright grain *

Coarse grains * *

Name

Leukoplakia *

Bending *

White dot *

1. the chemical composition does not agree with each other

Where the range of chemical composition of aluminum and aluminum alloy exceeds the national standard

(GB/T3190-1996) provides 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.

Causes

1- the chemical composition of the ingot in the factory does not meet the technical requirements or has no technical qualification 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 representation, 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 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 damaged the continuity of the whole ingot structure, 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 temperature 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 is 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 mark

As the friction between 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 serious 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;