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. 

The evaluation of heat treatments or the effectiveness of stabilisation by limiting carbon content of these stainless steels can be determined by subjecting specimens to the ASTM standardised acid copper sulphate test or boiling nitric acid test (ASTM A262 1986 see also Sections 9.5 and 1.3). 

This test has been developed and used by Streicher as a screening test to be used in conjunction with the tedious boiling nitric acid test for assessing the susceptibility of stainless steels to intergranular attack as specified in ASTM A262 1986, and will be considered subsequently in the section concerned with intergranular attack of Cr-Ni-Fe alloys. 

Nitric acid test t 65 wt.% HNOj Five 48 h exposures to boiling solution refreshed after period Average mass loss per unit area of five testing periods -1- 0-99 to -1- 1-20 1. Chromium-depleted areas 2. <7-phase 3. Chromium carbide... 

The recovered resin can be reconverted to the hydroxide form by eluting a column of the material with aqueous 10% sodium hydroxide until it is free of halide ion (silver nitrate-nitric acid test) and then with water until the eluent is no longer alkaline to pH paper. 

Part 1, p 874, Test A262-44T ("Tentative Recommended Practice for Boiling Nitric Acid Test for Corrosion-Resisting Steels ) Part 1, p 878, Test A279-44T (Total Immersion Corrosion Test for Stainless Steels) 18) Kirk Othmer 4 (1949)... 

The first observations on adverse renal effects of cadmium (Cd) exposure in humans were made by Friberg in the late 1940s [1]. He reported a high prevalence of proteinuria (65% using the nitric acid test and 81% using the trichloroacetic acid test) in Cd-exposed workers. 

III. Jia )cscc(t oil with Frcach iiut oil nadcr the nitric acid test the former, if ndul-icrated. assumes ft reddish liuge, more or less Intense, which alkali increases, and renders tho somi saponified mass more tibrous. 

Table 8 provides a summary of the redox potentials of various tests for austenitic and ferritic stainless steels. Because both carbides and molybdenum-rich sigma-phase may result in intergranular attack in highly oxidizing solutions, the nitric acid test should be specified for materials to be used in nitric acid or other highly oxidizing environments. 

Thus, the nitric acid test should be used primarily as a kind of simulated service test for alloys to be used in nitric acid environments. This is a return to its original function as defined by Huey [4]. When used in this way, it will be... 

DeLong, W. B., "Testing Multiple Specimens of Stainless Steels in a Modified Boiling Nitric Acid Test Apparatus," Symposium for Evaluation Tests for Stainless Steels, ASTM STP 93, ASTM International, West Conshohocken, PA, 1949, pp. 211-216. 

There are literally thousands of tests used by industritJ organizations for specific applications in electronics. Some are very specific, such as the nitric acid test for porosity in gold, (ISO 4524/2), for effects of vibration (lEC 68-2-6), for temperature (lEC 68-2-14), for solder (lEC 68-2-20), and for solderability (lEC 68-2-54), It is very common for laboratories to modify existing standardized tests to suit their specific needs. The technical literature will frequently describe these test conditions. 

The nitric acid test has also been applied less frequently to other austenitic, ferritic, and martensitic grades. Typically 24 h. 

The oxidation to the blue dye (III) takes place from either (I) or (II). The latter has the advantage that it better utilizes the oxidizing action of the nitric acid and prevents the oxidation from stopping at the diphenylbenzi-dine stage if an excess of diphenylamine is used. The nitric acid test is therefore more sensitive when diphenylbenzidine is used in place of di-phenylamine. ... 

A 65% solution of boiling nitric acid test revealed that ILLIUM PD is up to 10 times more resistant to attack than 316 stainless steel Test results... 

Precauiion.—Even when working with small quantities of material, special precaution must be observed in every nitric acid test, since certain organic substances may react violently. Losses of eyesight may easily result. 

Huey test. It is the nitric acid test described in ASTM A262-68 practice. 

The modified heat coagulation test and the salicyl sulphonic acid test are each about four times as sensitive as the nitric acid test. 

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