RESIDUAL STRESS (MERCUROUS NITRATE) TEST PROCEDURE
Mercurous Nitrate test is visual means of determining if stresses exist in brass cartridge
cases that may cause the cases to crack or split under conditions of storage or during service
Equipment listed in Mercurous Nitrate section of the appropriate Inspection Equipment List
shall be used.
30.0 MANDATORY SAFETY REQUIREMENTS
30.1 Food shall not be stored or eaten in vicinity in which these tests are conducted.
30.2 Acid resistant apron and gloves or the equivalent shall be worn by each test technician.
30.3 Face shields shall be worn at all times during the pouring or mixing of acids and water.
30.4 Asbestos or heat insulating gloves shall be worn during the heat volatilization phase of
the test to facilitate handling.
30.5 During the entire period of volatilization, the oven door shall be closed.
30.6 Extreme care shall be exercised in the mixing of acid with water; this shall be
accomplished by pouring the acid into the water.
30.7 Test shall be conducted under a canopy or hood having a forced draft ventilation
system to remove the noxious fumes. The disposition of tested components shall be governed by
40.0 TEST PROCEDURE
40.1 Preparation of Solution
40.1.1 Nitric-Acid Solution: Four hundred (400) milliliters of nitric acid (of specific gravity
1.42) are dissolved in five hundred (500) milliliters of distilled water at room temperature. To
this solution, distilled water is added to bring the volume of the resulting solution to one liter.
(The resultant specified gravity will be 1-25).
40.1.2 Mercurous Nitrate Solution: Ten (10) grams of mercurous nitrate and ten (10)
milliliters of nitric acid (of specified gravity1.42) are dissolved in four hundred (400) milliliters
of distilled water at room temperature. To this solution, distilled water is added to bring the
volume of the resulting solution to one liter.