Autoclave cleaning tests

Visual standard for surfaces of new steel airblast cleaned with sand abrasive Autoclave corrosion testing of metals in high temperature water... 

For each series of experiments, the same stainless steel coupon (4 cm X 3.5 cm X 0.1 cm) was precleaned, coated with the test contaminant, and then placed in the autoclave for testing. For precleaning, the coupon was either washed first in a chloroform bath, rinsed with acetone, and then dipped in an acetone bath or immersed in a 1,1,1-trichloroethane bath and wiped with a tissue to remove any residue. After precleaning, the coupon was weighed to determine when the mass of the coupon was within 0.1 mg of its original weight. This was set as the standard for perfect cleanness of the coupon. 

Rimless test-tubes fin. in diameter and about 6 in. long are used. They must be cleaned thoroughly each time they are used to remove trace residues which might interfere in subsequent assays. All detergents are not suitable and either one of the non-ionic preparations or a chromic acid-sulphuric acid mixture should be used. After cleaning, rinse the tubes in at least two changes of distilled water, then cover with metal caps or plug w ith cotton wool and sterilise in the autoclave at 115° (10 lb per sq. in. steam pressure) for twenty minutes. 

Only a few chemicals have definitely been established as human carcinogens. A well documented example is vinyl chloride, CH2=CHC1, whieh is known to have eaused a rare form of liver cancer (angiosarcoma) in individuals who cleaned autoclaves in Ihe polyvinylchloride fabrication industry. In some cases, chemicals are known to be carcinogens fi om epidemiological studies of e q)osed humans. Animals are used to test for carcinogenicity, and the results can be extrapolated—although with much uncertainty— to humans. 

A few experiment.s with Zircaloy-2 were carried out in autoclaves similar to the in-pile type [46] described in Article 5-2.2. In these experiments, the autoclave was constructed of Zircaloy-2 and was charged with the test solution, oxygen gas, and specimens. The test surfaces were as-machined and cleaned. Corrosion during exposure was determined by measuring the rate of oxygen loss within the system. The results of two of these experiments, H-54 and 11-55, are shown graphically in Fig. 5-15, where the thickness of the layer of metal which was converted to oxide or removed by oxidation is plotted on a log-log plot versus the exposure time. 

Industrial processing of adhesives has made considerable progress from the crude processes of the past [1]. Unfortunately, one of the disadvantages of adhesive bonding as an assembly method is that a bond area cannot be inspected visually. Inspection must be carried out by two methods destructive and nondestructive. Destructive inspection may be carried out on process-control test specimens prepared from the same adherend and adhesive materials as used for the production parts. The process-control specimen, as the name implies, accompanies the production parts throughout the stages of cleaning, assembly, and cure. The adhesives and adherends are all assembled at the same time and cured in the same press or autoclave. 

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