The GB 4157–84 Metal Anti-Sulphur Corrosion Stress Corrosion Cracking Constant Load Stretch Test Method is a standard created by the Chinese government to measure the susceptibility of a metal to stress corrosion cracking caused by sulphur. The purpose of this test is to determine the ability of a material to resist stress corrosion cracking caused by sulphur by measuring its elongation under various loads.
The test method consists of a stretching machine and a test specimen. A test specimen is placed in the stretching machine in a controlled temperature environment. The test specimen is then subjected to a constant load and its deformation is measured at varying temperatures. The elongation of the test specimen is then measured and results in determining the susceptibility of the material to stress corrosion cracking caused by sulphur.
The test specimen is usually made from stainless steel which is then heated to a specific temperature and then cooled slowly to the desired temperature. During the cooling stage, the steel is stressed gradually and its resistance to stress corrosion cracking caused by sulphur is then monitored.
It is important to note that different metals require different testing conditions. For instance, steel must be tested at higher temperatures in order to properly test its resistance to stress corrosion cracking. Copper and nickel, on the other hand, should be tested at lower temperatures due to their higher natural resistance to stress corrosion. The temperature of the test specimen should always be at least 10-15 degrees Celsius above its normal functioning temperature.
The results of this test are measured in terms of the mass loss of the test specimen over a specific period of time. The greater the mass loss, the greater the susceptibility of the material to stress corrosion cracking. The results of the GB 4157–84 Metal Anti-Sulphur Corrosion Stress Corrosion Cracking Constant Load Stretch Test Method should be compared to established acceptance standards in order to determine whether or not the material is suitable for use.
In summary, the GB 4157–84 Metal Anti-Sulphur Corrosion Stress Corrosion Cracking Constant Load Stretch Test Method is used to determine the susceptibility of a metal to stress corrosion cracking caused by sulphur. The test requires the placement of a test specimen in the stretching machine and the measurement of its deformation under varying levels of load and temperatures. The results of the test are measured in terms of its mass loss, with the greater loss indicating a higher susceptibility to stress corrosion cracking caused by sulphur. The results should then be compared to established standards in order to determine the suitability of the material for various applications.
