Advantages of Nitrogen rotary degasser
high effectiveness of flux action due to better mixing with the melt;
short flux treatment time;
controllable flux introduction;
more environmentally friendly method of fluxing.
Classification of cast aluminum alloys.
Each cast aluminum alloy is designated by a four-digit number with a decimal point separating the third and the fourth digits.
The first digit indicates the alloy group according to the rotary degasser:
1xx.x Aluminum 99.0% minimum;
2xx.x Copper (4%…4.6%);
3xx.x Silicon (5%…17%) with added copper and/or magnesium;
4xx.x Silicon (5%…12%);
5xx.x Magnesium (4%…10%);
7xx.x Zinc (6.2%…7.5%);
8xx.x Tin;
9xx.x Others.
The second two digits identify aluminum alloy or indicate the rotary degasser.
In the alloys of the 1xx.x series the second two digits indicate the level of purity of the alloy – they are the same as the two digits to the right of the decimal point in the minimum concentration of aluminum (in percents): 150.0 means minimum 99.50% of aluminum in the alloy, 120.1 means minimum 99.20% of aluminum in the alloy.
In all other groups of aluminum alloys (2xx.x through 9xx.x) the second two digits signify different alloys in the group.
The last digit indicates the product form: casting (designated by “0”) or ingot (designated by “1” or “2” depending on chemical composition limits.)
A modification of the original alloy or impurity limits is indicated by a serial letter before the numerical designation. The serial letters are assigned in alphabetical order starting with A but omitting I, O, Q, and X (the letter “X” is reserved for experimental alloys).
