ASTM G74-13 采用气态流体冲击的非金属材料和部件着火敏感度的标准试验方法标准

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标准号: ASTM G74-13
发布: 2013年
发布单位: 美国材料与试验协会
替代标准: ASTM G74-13(2021)
当前最新: ASTM G74-13(2021)

引用标准: ASTM D2463 ASTM D3182 ASTM D3183 ASTM D4894 ASTM D618 ASTM G128 ASTM G14 ASTM G175 ASTM G63 ASTM G88 ASTM G93 ASTM G94 ISO 10297 ISO 10524-1 ISO 10524-2 ISO 10524-3 ISO 14113 ISO 15001 ISO 23529 ISO 291 MIL-STD-1622

适用范围: 4.1 This test standard describes how to evaluate the relative sensitivity of materials and components to dynamic pressure impacts by various gaseous fluid media (can include gas mixtures).

4.2 Changes or variations in test specimen configurations, thickness, preparation, and cleanliness can cause a significant change in their impact ignition sensitivity/reaction. For material tests, the test specimen configuration shall be specified on the test report.

4.3 Changes or variation in the test system configuration from that specified herein may cause a significant change in the severity produced by a dynamic pressure surge of the gaseous media.

4.4 A reaction is indicated by an abrupt increase in test specimen temperature, by obvious changes in odor, color, or material appearance, or a combination thereof, as observed during post-test examinations. Odor alone is not considered positive evidence that a reaction has occurred. When an increase in test specimen temperature is observed, a test specimen reaction must be confirmed by visual inspection. To aid with visual inspection, magnification less than 10× can be used.

4.5 When testing components, the test article must be disassembled and the nonmetallic materials examined for evidence of ignition after completion of the specified pressure surge cycles.

4.6 Ignition or precursors to ignition for any test sample shall be considered a failure and are indicated by burning, material loss, scorching, or melting of a test material detected through direct visual means. Ignition is often indicated by consumption of the non-metallic material under test, whether as an individual material or within a component. Partial ignition can also occur, as shown in Fig. 3a, b, and c, and shall also be considered an ignition (failure) for the purpose of this test standard.

FIG. 3 a Untested PCTFE (10X Magnification) (Polychlorotrifluoroethylene) Sample.

FIG. 3 b Untested Nylon (PA, polyamide) Valve Seat (10X magnification) (continued)

Note 1—For the purpose of this standard, test samples that visually appear in these conditions, or similar, are considered to be representative of ignition.
FIG. 3 c Untested Pin-Index Sealing Washer (10X magnification) (continued)

FIG. 3 Photographs Representing Partial Reactions Including Scorching, Discoloration, Melting and Material Loss or Material Consumption. For the purpose of this standard, test samples that visually appear in these conditions, or similar, are considered to be representative of ignition.
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