ASTM D7671-10(R2021) pdf free download

ASTM D7671-10(R2021) pdf free download.Standard Test Method for Corrosiveness to Silver by Automotive Spark–Ignition Engine Fuel–Silver Strip Method
1. Scope
1.1 This test method covers the determination of the corro- siveness to silver by automotive spark-ignition engine fuel, as defined by Specification D4814, or similar specifications in other jurisdictions, having a vapor pressure no greater than 124 kPa (18 psi) at 37.8 °C (100 °F), by one oftwo procedures. Procedure A involves the use of a pressure vessel, whereas Procedure B involves the use of a vented test tube. 1.2 The result of the test is based on a visual rating that is classified as an integer in the range from 0 to 4 as defined in Table 1. 1.3 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability of regulatory limitations prior to use. For specific warning statements, see 6.1 and Section 7. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Summary of Test Method
3.1 This test method covers two procedures. Procedure A involves the use of a pressure vessel (to prevent the loss of volatile components in the sample), whereas Procedure B involves the use of a vented test tube. In both procedures, a freshly polished silver strip is suspended in 30 mL of sample which is heated to 50 °C 6 1 °C for a duration of 3 h 6 5 min. At the end of the heating period, the silver strip is removed, washed and the color and tarnish level assessed against the requirements in Table 1.
4. Significance and Use
4.1 Crude petroleum contains sulfur compounds, most of which are removed during refining. However, of the sulfur compounds remaining in the petroleum product, some can have a corroding action on various metals and this corrosivity is not related to the total sulfur content. In addition, fuels can become contaminated by corrosive sulfur compounds during storage and distribution. The corrosive effect can vary according to the chemical types of sulfur compounds present. 4.2 The silver strip corrosion test is designed to assess the relative degree of corrosivity of a petroleum product towards silver and silver alloys.4.3 Reactive sulfur compounds present in automotive spark- ignition engine fuels under some circumstances can corrode or tarnish silver alloy fuel gauge in-tank sender units (and silver-plated bearings in some 2-stroke cycle engines). To minimize or prevent the failure of silver alloy in-tank sender units by corrosion or tarnish, Specification D4814 requires that fuels shall pass the silver strip corrosion test.
5. Apparatus
5.1 Silver Strip Corrosion Pressure Vessel (Procedure A), constructed from stainless steel or similar strong and non- corroding metallurgy according to the dimensions as given in Fig. 1, that is the apparatus described in Test Method D130. The vessel shall be capable of withstanding a test pressure of 700 kPa gauge (100 psi). 5.1.1 Alternative designs for the vessel’s cap and synthetic rubber gasket may be used provided that the internal dimen- sions of the vessel are the same as those shown in Fig. 1. The internal dimensions of the pressure vessel are such that a nominal 25 mm by 150 mm test tube can be placed inside the pressure vessel. 5.2 Test Tubes, of borosilicate glass of nominal 25 mm by 150 mm dimensions. The internal dimensions shall be checked as acceptable by use of a silver strip (see 6.3). When 30 mL of liquid is added to the test tube with the silver strip in it, a minimum of 5 mm of liquid shall be above the top surface of the strip. 5.3 Stoppers (Procedure B), such as cork, to accompany test tubes in 5.2. Each stopper shall have a vent hole to equilibrate pressure that may build up in the test. The stoppers should be drilled through the center and fitted with a length of 3.2 mm ( 1 ⁄ 8 in.) OD glass or Nalgene vent tube.