GB/T 42793-2024General technical specification of aluminium alloy plates and sheets for aviation products (English PDF)

9.6.1.4 If the tensile mechanical properties of any specimen are unqualified, double the

number of specimens may be cut from the same master strip for repeated testing. If all repeated test results are qualified, the batch is considered qualified; if any specimen still fails to meet the performance requirements in the repeated test results, the batch is considered unqualified. With the agreement of both the supplier and the buyer, the supplier is allowed to inspect each piece individually and only qualified shall be delivered.

9.6.1.5 If the bending performance of any specimen is unqualified, double the number

of specimens may be cut from the same master strip for repeated testing. If all repeated test results are qualified, the batch is considered qualified; if any specimen still fails to meet the performance requirements in the repeated test results, the batch is considered unqualified. With the agreement of both the supplier and the buyer, the supplier is allowed to inspect each sheet individually and only qualified shall be delivered.

9.6.1.6 If the fatigue crack propagation rate of any specimen fails to meet the standard, double the number of specimens may be cut from the same base plate for repeated testing. If all repeated test results are satisfactory, the batch is deemed satisfactory; if any specimen fails to meet the standard in the repeated test results, the batch is deemed unsatisfactory.

9.6.1.7 If the plane stress fracture toughness of any specimen fails to meet the standard, the batch is deemed unsatisfactory. If the specimen width is not greater than 406 mm and the test result is invalid only because the net section stress validity criterion does not meet the requirements of GB/T 42914, an invalid KC or Kapp may be used to determine whether the specimen is satisfactory.

9.6.1.8 If the electrical conductivity of any specimen blank fails to meet the standard, the batch is deemed unsatisfactory.

9.6.1.9 If the electrical conductivity uniformity of any product fails to meet the standard, the batch is deemed unsatisfactory.

9.6.1.10 If the intergranular corrosion sensitivity of any specimen fails to meet the

standard, the batch is deemed unsatisfactory.

9.6.1.11 If any product fails ultrasonic flaw detection, that product is deemed

unqualified.

9.6.1.12 If the microstructure of any specimen is unqualified, the entire batch is deemed unqualified.

9.6.1.13 If the appearance quality of any specimen is unqualified, that product is

deemed unqualified.

9.6.2 Products with a thickness of not less than 6.35 mm

9.6.2.1 If the chemical composition of any specimen is unqualified, the batch of

products represented by that specimen is deemed unqualified.

9.6.2.2 If the dimensional deviation of any product is unqualified, that product is

deemed unqualified.

9.6.2.3 If the tensile properties of any specimen are unqualified, it is permissible to cut twice the number of specimens from the same base plate for repeated testing. If all repeated test results are qualified, the base plate is deemed qualified; if any specimen in the repeated test results still fails to meet the performance requirements, the base plate is deemed unqualified.

9.6.2.4 If the compressive properties of any specimen fail to meet the requirements,

double the number of specimens may be cut from the same base plate for repeated testing. If all repeated test results are satisfactory, the base plate is deemed satisfactory;

if any specimen fails to meet the requirements in the repeated tests, the base plate is deemed unsatisfactory.

9.6.2.5 Fatigue life results shall be determined according to Appendix C. Retesting is

permitted for individual fatigue specimens that do not meet the minimum fatigue life requirements of specific aluminum alloy product standards. Retest specimens shall be cut from a location immediately adjacent to the original sampling position.

9.6.2.6 If the fracture toughness of any specimen fails to meet the requirements, the base plate is deemed unsatisfactory. For plane strain fracture toughness, if the result obtained according to GB/T 42914 is "Batch release KQ", this KQ value can be used to determine whether the specimen is satisfactory. For plane stress fracture toughness, if the specimen width is not greater than 406 mm and the test result is invalid only because the net section stress effectiveness criterion does not meet the requirements of GB/T 42914, an invalid KC or Kapp value can be used to determine whether the specimen is satisfactory.

9.6.2.7 If the residual stress test of any specimen or sample fails, the entire batch is deemed unqualified.

9.6.2.8 If the electrical conductivity of any specimen blank fails, the entire base plate is deemed unqualified. However, sampling for stress corrosion resistance and exfoliation corrosion resistance tests is permitted. If all results of the stress corrosion resistance and exfoliation corrosion resistance tests are qualified, the base plate is deemed qualified;

if any specimen fails either the stress corrosion resistance or exfoliation corrosion resistance test, the entire base plate is deemed unqualified. If the electrical conductivity uniformity of any product fails, the entire batch is deemed unqualified.

9.6.2.9 If the matching relationship between the electrical conductivity and mechanical

properties of any specimen blank fails, the entire base plate is deemed unqualified.

9.6.2.10 If the stress corrosion resistance of any specimen fails, the entire batch is deemed unqualified.

9.6.2.11 If the exfoliation corrosion resistance of any specimen fails, the entire batch is deemed unqualified.

9.6.2.12 If any product fails the ultrasonic flaw detection test, that product is deemed unqualified.

9.6.2.13 If the low-magnification microstructure of any specimen is unqualified, the

entire batch is deemed unqualified.

9.6.2.14 If the microstructure of any specimen is unqualified, the entire batch is deemed unqualified.

9.6.2.15 If the appearance quality of any specimen is unqualified, that product is

deemed unqualified.

10.1 Marking

10.1.1 Product marking

Product marking shall comply with the provisions of GB/T 42916; continuous inkjet coding should be adopted.

10.1.2 Packaging box marking

Packaging box marking shall comply with the provisions of GB/T 3199.

10.2 Packaging, transportation, storage

Products shall not be oiled; they shall be packaged with paper padding between boards.

Any other requirements shall be specified in the order form (or contract). Other packaging, transportation, storage requirements shall comply with GB/T 3199.

10.3 Certificate of quality

Each batch of products shall be accompanied by a certificate of quality, which shall specify.

a) Supplier's name and address;

b) Product name;

c) Designation, condition, dimensions;

d) Batch number;

e) Net weight or box (sheet);

f) Document number;

g) Results of all analytical tests and the supplier's quality inspection department's stamp;

h) Packaging date (or exit-factory date).