ASTM D7667-10
(Test Method)Standard Test Method for Determination of Corrosiveness to Silver by Automotive Spark-Ignition Engine FuelThin Silver Strip Method
Standard Test Method for Determination of Corrosiveness to Silver by Automotive Spark-Ignition Engine Fuel<char: emdash>Thin Silver Strip Method
SIGNIFICANCE AND USE
Crude petroleum contains sulfur compounds, most of which are removed during refining. However, of the sulfur compounds remaining in the petroleum product or introduced into the fuel during storage and distribution, some can have a corroding action on various metals and this corrosivity is not necessarily related directly to the total sulfur content. The effect can vary according to the chemical types of sulfur compounds present. The silver strip corrosion test is designed to assess the relative degree of corrosivity of a petroleum product towards silver and silver alloys.
Under some circumstances, reactive sulfur compounds present in automotive spark-ignition engine fuels can tarnish or even corrode silver alloy fuel gauge in-tank sender units or silver-plated bearings (in 2-stroke cycle engines). To minimize or prevent the failure of silver alloy in-tank sender units by tarnish or corrosion, Specification D4814 requires that fuels shall pass a silver strip corrosion test.
SCOPE
1.1 This test method covers the determination of the corrosiveness to silver by automotive spark-ignition engine fuel (for example, gasoline), 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 of two procedures.
1.1.1 Procedure A—Involves the use of a pressure vessel.
1.1.2 Procedure B—Involves the use of a vented test tube.
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.
1.3 WARNINGMercury has been designated by many regulatory agencies as a hazardous material that can cause central nervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet (MSDS) for details and EPA’s websitehttp://www.epa.gov/mercury/faq.htmfor additional information. Users should be aware that selling mercury and/or mercury containing products into your state or country may be prohibited by law.
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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
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Designation: D7667 – 10
Standard Test Method for
Determination of Corrosiveness to Silver by Automotive
Spark-Ignition Engine Fuel—Thin Silver Strip Method
This standard is issued under the fixed designation D7667; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D4057 Practice for Manual Sampling of Petroleum and
Petroleum Products
1.1 This test method covers the determination of the corro-
D4177 Practice for Automatic Sampling of Petroleum and
siveness to silver by automotive spark-ignition engine fuel (for
Petroleum Products
example, gasoline), as defined by Specification D4814 or
D4814 Specification for Automotive Spark-Ignition Engine
similar specifications in other jurisdictions, having a vapor
Fuel
pressure no greater than 124 kPa (18 psi) at 37.8°C (100°F) by
E1 Specification for ASTM Liquid-in-Glass Thermometers
one of two procedures.
2.2 Energy Institute Standards:
1.1.1 Procedure A—Involves the use of a pressure vessel.
IP227 Determination of Corrosiveness to Silver ofAviation
1.1.2 Procedure B—Involves the use of a vented test tube.
Turbine Fuels - Silver Strip Method
1.2 The values stated in SI units are to be regarded as the
2.3 ASTM Adjuncts:
standard. The values in parentheses are for information only.
Color standard for tube deposit rating (5 aluminum strips)
1.3 WARNING—Mercury has been designated by many
regulatory agencies as a hazardous material that can cause
3. Terminology
central nervous system, kidney and liver damage. Mercury, or
3.1 Abbreviations:
its vapor, may be hazardous to health and corrosive to
materials.Cautionshouldbetakenwhenhandlingmercuryand
mercury containing products. See the applicable product Ma-
PTFE = polytetrafluoroethylene
terial Safety Data Sheet (MSDS) for details and EPA’s
PV = pressure vessel
website—http://www.epa.gov/mercury/faq.htm—for addi-
PVP = pressure vessel procedure
tional information. Users should be aware that selling mercury
SSCD = silver strip centering device
and/or mercury containing products into your state or country TSMD = temperature sensing and monitoring device
may be prohibited by law. VTTP = vented test tube procedure
1.4 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 4.1 Apolished, thin silver strip is immersed in 30 mLof the
priate safety and health practices and determine the applica- sample being tested, and heated at 50°C (122°F) for 2 h.At the
bility of regulatory limitations prior to use. end of the heating period, the silver strip is removed, washed,
and the color and tarnish level assessed against the Silver Strip
2. Referenced Documents
Classifications in Table 1.
2.1 ASTM Standards:
5. Significance and Use
D130 Test Method for Corrosiveness to Copper from Pe-
troleum Products by Copper Strip Test 5.1 Crude petroleum contains sulfur compounds, most of
which are removed during refining. However, of the sulfur
D3241 Test Method for Thermal Oxidation Stability of
Aviation Turbine Fuels compounds remaining in the petroleum product or introduced
into the fuel during storage and distribution, some can have a
corroding action on various metals and this corrosivity is not
necessarily related directly to the total sulfur content. The
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
effect can vary according to the chemical types of sulfur
D02.05.0C on Color and Reactivity.
Current edition approved Oct. 1, 2010. Published December 2010. DOI:
10.1520/D7667–10.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM U.K., http://www.energyinst.org.uk.
Standards volume information, refer to the standard’s Document Summary page on Available from ASTM International Headquarters. Order Adjunct No.
the ASTM website. ADJD3241. Original adjunct produced in 1986.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7667 – 10
TABLE 1 Silver Strip Classifications
NOTE—Acknowledgement—This table has been reproduced from Standard IP 227.
Classification Designation Description
0 No Tarnish Identical to a freshly-polished strip but may have some very slight
loss of luster
1 Slight Tarnish Faint brown or white discoloration of strip (see 12.2)
2 Moderate Tarnish Peacock colors such as blue or mauve or medium/dark straw or
brown coloration (see 12.2)
3 Slight blackening Spots and patches of black or gray on surface or uniform thin film of
black deposit
4 Blackening Uniform heavy blackening with or without scaling
compounds present. The silver strip corrosion test is designed
to assess the relative degree of corrosivity of a petroleum
product towards silver and silver alloys.
5.2 Under some circumstances, reactive sulfur compounds
presentinautomotivespark-ignitionenginefuelscantarnishor
even corrode silver alloy fuel gauge in-tank sender units or
silver-plated bearings (in 2-stroke cycle engines). To minimize
or prevent the failure of silver alloy in-tank sender units by
tarnish or corrosion, Specification D4814 requires that fuels
shall pass a silver strip corrosion test.
6. Apparatus
6.1 Silver Strip Corrosion Pressure Vessel (Procedure A),
constructed from stainless steel according to dimensions given
in Fig. 1, as described in Test Method D130. The vessel shall
becapableofwithstandingatestpressureof700kPa(100psi).
Alternative designs for the vessel’s cap and synthetic rubber
gasketmaybeusedprovidedthattheinternaldimensionsofthe
vessel are the same as shown in Fig. 1, which allow a nominal
25by150mm(1by6in.)testtube(see6.2)andtheSSCD(see
6.4) to be placed inside the pressure vessel.
6.2 Test Tubes, of borosilicate glass of nominal 25 by
150 mm(1by6in.)dimensions,preferablygraduatedat30mL
,
5 6
volume. The internal dimensions shall be checked as accept-
able by use of a silver strip (see 7.4). When 30 mL of sample
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.
6.3 Test Bath, General, whether liquid or solid, the test bath
shall be able to maintain the test temperature to within 61°C
(2°F) of the required test temperature. It is recommended that
baths be placed inside a fume-hood.
6.3.1 Bath,shallbefittedwithsuitablesupportstoholdeach
test tube (see 6.2) in a vertical position to a depth of about 100
mm (4 in.) as measured from the bottom of the test tube to the
bath surface.
6.3.2 BathMedium,asaliquidbathmedium,bothwaterand
oil have been found to be satisfactory and controllable at the
specified test temperature and duration required by the test
procedure.
The sole source of supply of the apparatus known to the committee at this time
FIG. 1 Pressure Vessel for Silver Strip Corrosion Test –
is Quark Enterprises, Inc., 320 Morton Ave., Rosenhayn, NJ 08352.
Procedure A
If you are aware of alternative suppliers, please provide this information to
ASTM International Headquarters. Your comments will receive careful consider-
ation at a meeting of the responsible technical committee, which you may attend.
D7667 – 10
6.3.3 Solid Block Bath, made of aluminum, shall meet the 7. Reagents and Materials
test temperature control, test duration, and immersion condi-
7.1 Wash Solvent, 2,2,4-trimethylpentane (iso-octane) of
tions required by the test procedure, and shall be verified, at
minimum 99.75% purity. (Warning—Extremely flammable,
least annually, for temperature measurement (heat transfer) by
see 8.1.)
running tests on tubes filled with 30 mL of product plus a thin
7.2 Surface Preparation/Polishing Material, Scouring-pad,
silver strip of the given nominal dimensions, plus a tempera-
approximately 400-grit, made of polyester material that is free
ture sensor.
of detergents or spongy material, containing aluminum oxide
,
6 8
6.3.3.1 Wells provided in the solid block bath to accommo-
as a scouring-aid.
date pressure vessels (see Fig. 1) shall be of the following
NOTE 1—Some 400-grit pads are commercially available in the form of
dimensions: ~54 mm (2 ⁄8 in.) diameter from top, up to a depth
229 by 152 by 9.5 mm (9 by 6 by ⁄8 in.) thick pads. For ease of handling
of ~70 mm (2 ⁄4 in.) continuing with an opening of ~38 mm
and polishing, it is recommended that the pads be cut so that the
1 1
(1 ⁄2 in.) diameter up to a depth of ~140 mm (5 ⁄2 in.). An 1
dimensions of the scouring-pads are about 114 by 38 by 9.5 mm ( 4 ⁄2 by
5 1
1 3
opening of ~8 mm ( ⁄16 in.) diameter by ~210 mm (8 ⁄4 in.) 1 ⁄2 by ⁄8 in.).
depthshallbeprovidedinthecenteroftheblockforimmersion
7.3 Waterproof Aluminum Oxide Cloth Sanding Sheets or
,
of a metal temperature sensor (connected to a suitable 50 6 6 9
Rolls, 150-grit.
1°C (122 6 2°F) temperature controller), or thermometer (see
7 9
7.4 Silver Strips, Use strips 36.0 to 40.0 mm (1 ⁄16 to 1 ⁄16
6.5).
15 1
in.) long, 6.25 to 6.35 mm ( ⁄64 to ⁄4 in.) wide and 0.526 to
6.3.3.2 Wells provided in the solid block bath to accommo-
0.541 mm ( ~1 ⁄64 in.) thick, assaying at 99.9% (m/m) Ag
,
6 10
date test tubes shall be of the following dimensions: ~20 mm
minimum. When necessary, cut, straight and smooth, using
1 1
(1 ⁄16 in.) diameter by ~140 mm (5 ⁄2 in.) deep.An opening of
a sharp tin-snip or any other metal-cutting device, (such as a
5 1 ,
6 11
~8 mm ( ⁄16 in.) diameter by ~210 mm (8 ⁄4 in.) depth shall be
heavy-duty ~152 mm (6 in.) shear ) approximately 38.0 mm
provided in the center of the block for immersion of a metal
(1 ⁄2 in.) long strips from the longer strips supplied. Strips may
temperature sensor (connected to a suitable 50 6 1°C (122 6
be used repeatedly, but should be discarded when the original
2°F) temperature controller), or thermometer (see 6.5).
shapebecomesdeformed,orsurfaceshowspitting,scratchesor
6.3.3.3 Provide insulation made of ~25.4 mm (1.0 in.) thick tarnish that cannot be removed by the specified polishing
fiberglass with aluminum backing (or, similar insulation) to
procedure.
cover all the four sides of the solid block bath. 7.5 Ashless Filter Paper or Disposable Gloves or Finger-
6,7
Tip Protectors, for use in protecting the silver strip from
6.4 Silver Strip Centering Device (SSCD), made of ma-
coming in contact with the individual during polishing.
terial which is gasoline-compatible at 50°C (122°F) for the
duration of the test, such asAcetal Resin, White Nylon 6/6, or
8. Hazards
PTFE. See details in A1.1(Assembly View) and A1.2 (Indi-
vidualPartsView).LengthofSSCDinsidethetesttubeissuch 8.1 Wash Solvent.(Warning— iso-octane: Harmful if in-
thattheloweredgeoftheassembledsilverstripisabout22mm haled. Vapors may cause flash fire. Keep away from heat,
( ⁄8 in.) from the bottom of the test tube. sparks and open flames, and container closed. Use with
adequate ventilation. Avoid build-up of vapors and eliminate
6.5 Temperature Sensing and Monitoring Device (TSMD),
all sources of ignition, especially non-explosion-proof electri-
capable of sensing and monitoring the desired test temperature
cal apparatus and heaters.Avoid prolonged breathing of vapor
in the bath to within an accuracy of 61°C (2°F). The ASTM
or spray mist.)
12C (12F) (see Specification E1) or IP 64C (64F) total
8.2 Gasoline, (Unleaded or Leaded).(Warning—Keep
immersion thermometer has been found suitable for use in the
away from heat, sparks and open flames, and container closed.
test. If used, no more than 10 mm (0.4 in.) of the mercury shall
Use with adequate ventilation. Avoid build-up of vapors and
extend above the surface of the bath at the test temperature.
eliminate all sources of ignition, especially non-explosion-
6.6 Timing Device, electronic or manual, capable of accu-
proof electrical apparatus and heaters.Avoid prolonged breath-
rately measuring the test duration within the allowable toler-
ing of vapor or spray mist. Avoid prolonged or repeated skin
ance.
contact.)
6.7 Forceps, with inert tips, stainless steel or polytetrafluo-
8.3 PressureVessel, heat and pressure will be built-up in the
roethylene (PTFE) tips, have been found suitable for use in
pressure vessel during the test. After the test, cool and
handling the silver strips.
depressurize pressure vessel carefully and fully before opening
6.8 Polishing Board,150by100by3mm(6by4by ⁄8 in.)
it for inspection of the silver strip.
solid plastic piece having a smooth surface, for placement of
silver strip during polishing.
6.9 Optional Equipment:
The sole source of supply of the apparatus known to the committee at this time
is 3M’s “Scotch Brite 86” scouring pads (114 by 38 by 9.5 mm thick cut pieces)
6.9.1 Refrigerator, for cooling samples below 5°C (41°F)
were used in the ruggedness study.
during storage.
The sole source of supply of the apparatus known to the committee at this time
is Part No. 8225A22 (1 ⁄2 width roll), McMaster Carr Supply Co.
Thesolesourceofsupplyoftheapparatusknowntothecommitteeatthistime
is pre-cut silver strips, C&P Catalyst, PO Box 520984, Tulsa, OK 74152.
7 11
The sole source of supply of the apparatus known to the committee at this time Thesolesourceofsupplyoftheapparatusknowntothecommitteeatthistime
isK&C Manufacturing, 210 S. Main, Newkirk, OK 74647. is Part No. 82818, Micro-mark, 340 Snyder Ave., Berkeley Heights, NJ 07922.
D7667 – 10
9. Samples and Sample Preparation loweredgeoftheassembledsilverstripisabout22mm( ⁄8in.)
from the bottom of the test tube.
9.1 Collect samples according to Practices D4057 or D4177
11.1.3 Carefully place the test tube in the pressure vessel,
in clean, amber bottles made of borosilicate glass.
and screw the lid on tightly.
9.2 Close containers immediately after filling them to be-
tween 70 to 85% of their capacity. Adequate headspace in the 11.1.4 Place the pressure vessel in a bath maintained at 50
container is necessary to provide room for possible thermal 6 1°C (122 6 2°F), and note the time at which this is done.
expansion during transport.
11.1.5 If more than one sample is to be analyzed at
9.3 Take care during sampling, transportation and storage to
essentially the same time, it is permissible to prepare each
protect the samples from exposure to direct sunlight or ev
...
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