GB/T 22638.1-2016Test methods for aluminium and aluminium alloy foils - Part 1: Determination of thickness (English PDF)

4.2.1 Analytical balance, sensitivity

0.1 mg.

4.2.2 Sampler, a sampler for quantitative standard specimens with a punching area of 100 cm^2.

4.3 Determination

4.3.1 After removing the wrinkled outer layer of the aluminum foil roll, cut a sample from the roll and sandwich the sample between two sheets of paper with an area greater than 100 cm^2. The paper used shall not cause defects in the sample.

4.3.2 Use a sampler (4.2.2) to punch one specimen at a time from the sandwiched aluminum foil. The area deviation of the specimen shall not exceed ±

0.35 cm^2.

4.3.3 It shall wipe the specimen with anhydrous ethanol or other suitable solvent before testing to remove oil or dirt.

4.3.4 Weigh the clean and dry specimen on an analytical balance (4.2.1) to an accuracy of four decimal places; record its mass m.

4.3.5 Repeatedly weigh the same specimen on different balances for calibration. The result error shall be controlled within ±1 mg. Otherwise, the balance shall be repaired or recalibrated.

4.4.1 Calculation of density of aluminum or aluminum alloy

4.4.1.1 Calculation of the arithmetic mean of mass fraction of each element in the tested aluminum or aluminum alloy 4.4.1.1.1 The arithmetic mean of the mass fraction of the elements shall be calculated based on the limit values of the mass fraction of the elements. When only the maximum limit value of the mass fraction of an element is specified, its minimum limit value is considered zero. The arithmetic mean shall be rounded to the significant figures shown in Table 1. 4.4.1.1.2 For composite elements where only the maximum value is specified for the mass fraction limit, such as (iron + silicon), each individual element is considered to have an equal mass fraction. The arithmetic mean of its mass fractions is calculated by dividing the arithmetic mean of the mass fractions of the composite elements (calculated and rounded according to 4.4.1.1.1) by the number of individual elements in the composite element. The result is rounded to the significant digits shown in Table 1. 4.4.1.1.3 When the mass fraction of aluminum is greater than or equal to 99.90% but less than or equal to 99.99%, its arithmetic mean is determined by subtracting the sum of the arithmetic means of the mass fractions of all elements whose maximum mass fraction limit is not less than 0.0010% from 100.00%. Before summing, the arithmetic mean of the mass fractions of each element shall be expressed to the nearest 0.0××%. After summing, the sum shall be rounded to 0.0×%. 4.4.1.1.4 When the mass fraction of aluminum is greater than or equal to 99.00% but less than 99.90%, its arithmetic mean is determined by subtracting the sum of the arithmetic means of the mass fractions of all elements whose maximum mass fraction limit is not less than 0.010% from 100.00%. Before summing, the arithmetic mean of the mass fractions of each element shall be expressed to the nearest 0.0×%. 4.4.1.1.5 When the mass fraction of aluminum is less than 99.00%, its arithmetic mean is calculated by subtracting the sum of the arithmetic means of the mass fractions of each element from 100.00%, rounding the result to two decimal places.