Intergranular corrosion 65% nitric acid test

Remove the Nitric Acid Test from ASTM A 262 and establish it as a separate ASTM Test At present, the boiling 65 % nitric acid test (Practice C) is specified for materials to be used in nitric acid service. Only this test is sensitive to sigma-phase in molybdenum-bearing austenitic stainless steels. Also, problems such as end-grain corrosion associated with hexavalent chromium derived from corrosion products are unique to this solution. While this test also detects susceptibility to intergranular attack associated with chromium carbide precipitates, there are other tests that perform this function in less time and with greater simplicity. 

Test method for determining the susceptibility to intergranular corrosion of 5XXX series aluminium alloys by mass loss after exposure to nitric acid (NAMLT test) Practice for liquid sodium corrosion testing of metals and alloys... 

Austenitic stainless steels-determination of resistance to intergranular corrosion. Part 1 Corrosion test in nitric acid medium by measurement of loss of mass (Huey test) Austenitic stainless steels-determination of resistance to intergranular corrosion. Part 2 Corrosion test in a sulphuric acid/copper sulphate medium in the presence of copper turnings (Moneypenny Strauss test)... 

ASTM Standard G 67, Standard Test Method for Determining the Susceptibility to Intergranular Corrosion of 5XXX Series Aluminum Alloys by Mass Loss After Exposure to Nitric Acid, Annual Book of ASTM, 1999, 03.02. 

ASTM A-262 [7.21] has standardized five different methods for testing intergranular corrosion of austenitic stainless steels, after Streicher (two), Huey, Warren and Strauss. The Warren test, using exposure to nitric acid-fluoric acid, is particularly suited for molybdenium-alloyed steels. 

Intergranular corrosion of titanium (and various of its alloys) occurs in fuming nitric acid at room temperature (3- to 16-h tests). Addition of 1% NaBr acts as an inhibitor [30]. Similar corrosion of commercially pure titanium occurs in methanol solutions containing Br2, CB, or I2 or Br , CT, or 1 [31]. Water acts as an inhibitor. 

It was soon found that among the variables affecting corrosion rates were certain heat treatments that made not only the ferritic stainless steels subject to intergranular attack, but also the austenitic, 18Cr-8Ni alloys. From this simulated service test in boiling 65 % nitric acid, there evolved Practice C of ASTM A 262. Its large-scale use by one... 

Information on "acceptable and nonacceptable corrosion test results has been given for the two EPR tests in the section above on these tests. Acceptable etch structures (step, and in some cases, dual) are also identified for the oxalic acid etch test. The absence of fissures in bends after certain copper sulfate tests is considered an indication of acceptable results. However, in the case of weight-loss tests (nitric acid, ferric sulfate, and certain copper sulfate tests) the standard ASTM test methods merely show how corrosion rates are calculated without identification of rates which are evidence of the onset of susceptibihty to intergranular attack. 

A rather unique mass loss test method, ASTM G 67 (Test Method for Determining the Susceptibility of Intergranular Corrosion of 5xxx Series Aluminum Alloys by Mass Loss After Exposure to Nitric Acid [NAMLT Test]) has been developed to provide a quantitative measure of the intergranular susceptibility of 5xxx series Al-Mg and Al-Mg-Mn allo3rs. The technique is useful to determine whether material has become sensitized by exposure to elevated temperature. Development of the test is reported in Ref 23. 

AFNOR (1998) NF EN ISO 3651-1 1998. Determination of Resistance to Intergranular Corrosion of Stainless Steels. Part 1 Austenitic and Ferritic-Austenitic (Duplex) Stainless Steels. Corrosion Test in Nitric Acid Medium by Measurement of Loss in Mass (Huey Test), AFNOR, Paris. 

Huey test Corrosion testing in a boiling solution of nitric acid. This test is mainly used to detect the susceptibility to intergranular corrosion of stainless steel. 

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