Stress Corrosion Cracking Resistance Test Equipment for Low Copper 7XXX Series Al-Zn-Mg-Cu Alloys in Boiling 6 % Sodium Chloride Solution

4- point bend ssc test

Caltech Engineering Services, Mumbai India offers Stress Corrosion Cracking Resistance Test Equipment for Low Copper 7XXX Series Al-Zn-Mg-Cu Alloys in Boiling 6 % Sodium Chloride Solution.

In this test method G103, Stressed specimens are totally and continuously immersed in boiling 6 % sodium chloride solution for up to 168 hours. Various types of smooth test specimens and methods of stressing may be used. Performance is based on time to visual. This stress corrosion testing practice is intended for statically loaded smooth non-welded or welded specimens of 7XXX series Al-Zn-Mg-Cu alloys containing less than 0.26 % copper.

Test Vessel will contain test solution and reflux condenser as per requirement of ASTM G103 Standard. Tension specimens as per G 49 are more suitable for thicker products and for short transverse testing.

ASTM G103 test method is a Continuous immersion in boiling 6 % sodium chloride solution historically was considered to be an effective accelerated SCC testing medium for all Al-Zn-Mg-Cu alloys (1, 2),2 but in more recent years, alternate immersion in 3.5 % sodium chloride solution (Practice G 44) has become the favored test medium for the high copper (1.2 to 2.6 % Cu) 7XXX series alloys (3, 4).

Evidence to date shows that the boiling 6 % sodium chloride medium correlates better with outdoor atmospheric exposure than Practice G 44 for the 7XXX series alloys containing little or no copper.

References

G 30 Practices for Making and Using U-Bend Stress- Corrosion Test Specimens

G 38 Practices for Making and Using C-Ring Stress Corrosion Test Specimens

G 39 Practices for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens

G 44 Practices for Evaluating Stress Corrosion Cracking Resistance of Metals and Alloys by Alternate Immersion in 3.5 % Sodium Chloride Solution

G 49 Practices for Preparation and Use of Direct Tension Stress Corrosion Test Specimens

G 58 Practices for Preparation of Stress-Corrosion Test Specimens for Weldments