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ASTM E328-02

(Test Method)

Standard Test Methods for Stress Relaxation Tests for Materials and Structures

Standard Test Methods for Stress Relaxation Tests for Materials and Structures

SIGNIFICANCE AND USE
Relaxation test data are necessary when designing most mechanically fastened joints to assure the permanent tightness of bolted or riveted assemblies, press or shrink-fit components, rolled-in tubes, etc. Other applications include predicting the decrease in the tightness of gaskets, in the hoop stress of solderless wrapped connections, in the constraining force of springs, and the stability of wire tendons in prestressed concrete.
The ability of a material to relax at high-stress concentrations such as are present at notches, inclusions, cracks, holes, fillets, etc., may be predicted from stress relaxation data. Such test data are also useful to judge the heat-treatment condition necessary for the thermal relief of residual internal stresses in forgings, castings, weldments, machined or cold-worked surfaces, etc. The tests outlined in these methods are limited to conditions of approximately constant constraint and environment.
The test results are highly sensitive to small changes in environmental conditions and thus require precise control of test conditions and methods.
The reproducibility of data will depend on the manner with which all test conditions are controlled. The effects of aging or residual stress may significantly affect results, as may variations in material composition.
SCOPE
Note 1—The method of testing for the stress relaxation of plastics has been withdrawn from this standard, and the responsibility has been transferred to Practice D 2991.
1.1 These test methods cover the determination of the time dependence of stress (stress relaxation) in materials and structures under conditions of approximately constant constraint, constant environment, and negligible vibration. In the procedures recommended, the material or structure is initially constrained by externally applied forces, and the change in the external force necessary to maintain this constraint is determined as a function of time.
1.2 Specific methods for conducting stress relaxation tests on materials subjected to tension, compression, bending and torsion stresses are described in Parts A, B, C, and D, respectively. These test methods also include recommendations for the necessary testing equipment and for the analysis of the test data.
1.3 It is recognized that the long time periods required for these types of tests are often unsuited for routine testing or for specification in the purchase of material. However, these tests are valuable tools in obtaining practical design information on the stress relaxation of materials subjected to the conditions enumerated, and in investigations of the fundamental behavior of materials.
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.

General Information

Status
Historical
Publication Date
09-Nov-2002
ICS
19.020 - Test conditions and procedures in general
Technical Committee
E28 - Mechanical Testing
Drafting Committee
E28.04 - Uniaxial Testing
Current Stage
Ref Project

Relations

Replaces
ASTM E328-86(1996)e1 - Standard Test Methods for Stress Relaxation Tests for Materials and Structures
Effective Date
10-Nov-2002
Replaced By
ASTM E328-02(2008) - Standard Test Methods for Stress Relaxation Tests for Materials and Structures
Effective Date
01-May-2008
Referred By
ASTM F2902-16e1 - Standard Guide for Assessment of Absorbable Polymeric Implants
Effective Date
10-Nov-2002
Referred By
ASTM A911/A911M-21 - Standard Specification for Low-Relaxation Steel Bars for Prestressed Concrete Railroad Ties
Effective Date
10-Nov-2002
Referred By
ASTM A648-18 - Standard Specification for Steel Wire, Hard-Drawn for Prestressed Concrete Pipe
Effective Date
10-Nov-2002
Referred By
ASTM A421/A421M-21 - Standard Specification for Stress-Relieved Steel Wire for Prestressed Concrete
Effective Date
10-Nov-2002
Referred By
ASTM E633-21a - Standard Guide for Use of Thermocouples in Elevated-Temperature Mechanical Testing
Effective Date
10-Nov-2002
Referred By
ASTM A1061/A1061M-20ae1 - Standard Test Methods for Testing Multi-Wire Steel Prestressing Strand
Effective Date
10-Nov-2002
Referred By
ASTM A193/A193M-23 - Standard Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications
Effective Date
10-Nov-2002
Referred By
ASTM F2789-10(2020) - Standard Guide for Mechanical and Functional Characterization of Nucleus Devices
Effective Date
10-Nov-2002

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ASTM E328-02 - Standard Test Methods for Stress Relaxation Tests for Materials and StructuresASTM E328-02 - Standard Test Methods for Stress Relaxation Tests for Materials and Structures
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ASTM E328-02 - Standard Test Methods for Stress Relaxation Tests for Materials and Structures
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E328–02
Standard Test Methods for
1
Stress Relaxation for Materials and Structures
This standard is issued under the fixed designation E328; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
These test methods cover a broad range of testing activities. To aid in locating the subject matter
pertinent to a particular test, the standard is divided into a general section, which applies to all stress
relaxationtestsformaterialsandstructures.Thisgeneralsectionisfollowedbyletter-designatedparts
that apply to tests for material characteristics when subjected to specific, simple stresses, such as
uniform tension, uniform compression, bending or torsion. To choose from among these types of
stress, the following factors should be considered:
(1) When the material data are to be applied to the design of a particular class of component, the
stress during the relaxation test should be similar to that imposed on the component. For example,
tension tests are suitable for bolting applications and bending tests for leaf springs.
(2) Tension and compression relaxation tests have the advantage that the stress can be reported
simply and unequivocally. During bending relaxation tests, the state of stress is complex, but can be
accurately determined when the initial strains are elastic. If plastic strains occur on application of
force, stresses can usually be determined within a bounded range only.Tension relaxation tests, when
compared to compression tests, have the advantage that it is unnecessary to guard against buckling.
Therefore,whenthetestmethodisnotrestrictedbythetypeofstressinthecomponent,tensiontesting
is recommended.
(3) Bending tests for relaxation, when compared to tension and compression tests, have the
advantage of using lighter and simpler apparatus for specimens of the same cross-sectional area.
Strains are usually calculated from deflection or curvature measurements. Since the specimens can
usually be designed so that these quantities are much greater than the axial deformation in a direct
stress test, strain is more easily measured and more readily used for machine control in the bending
tests.Duetothesmallforcesnormallyrequiredandthesimplicityoftheapparatuswhenstaticfixtures
are sufficient, many specimens can be placed in a single oven or furnace when tests are made at
elevated temperatures.
1. Scope 1.2 Specific methods for conducting stress relaxation tests
on materials subjected to tension, compression, bending and
NOTE 1—The method of testing for the stress relaxation of plastics has
torsion stresses are described in Parts A, B, C, and D,
been withdrawn from this standard, and the responsibility has been
respectively.Thesetestmethodsalsoincluderecommendations
transferred to Practice D2991.
for the necessary testing equipment and for the analysis of the
1.1 These test methods cover the determination of the time
test data.
dependence of stress (stress relaxation) in materials and
1.3 It is recognized that the long time periods required for
structures under conditions of approximately constant con-
these types of tests are often unsuited for routine testing or for
straint, constant environment, and negligible vibration. In the
specification in the purchase of material. However, these tests
procedures recommended, the material or structure is initially
are valuable tools in obtaining practical design information on
constrained by externally applied forces, and the change in the
the stress relaxation of materials subjected to the conditions
external force necessary to maintain this constraint is deter-
enumerated, and in investigations of the fundamental behavior
mined as a function of time.
of materials.
1.4 This standard does not purport to address all of the
1
These test methods are under the jurisdiction of ASTM Committee E28 on
safety concerns, if any, associated with its use. It is the
Mechanical Testing and is the direct responsibility of Subcommittee E28.04 on
responsibility of the user of this standard to establish appro-
Uniaxial Testing.
priate safety and health practices and determine the applica-
Current edition approved Nov. 15, 2005. Published April 2003. Originally
e1
approved in 1967. Last previous approved 1986 as E328–86(96) . bility of regulatory limitations prior to use.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
E328–02
FIG. 1 Characteristic Behavior During Force Application Period in a Relaxation Test
2. Referenced Documents should
...

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5.1 Stress-relaxation test data are necessary when designing most mechanically fastened joints to ensure the permanent tightness of bolted or riveted assemblies, press or shrink-fit components, rolled-in tubes, etc. Other applications include predicting the decrease in the tightness of gaskets, in the hoop stress of solderless wrapped connections, in the constraining force of springs, and in the stability of wire tendons in prestressed concrete.  
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5.4 There are many methods of performing the stress-relaxation test, each with a different starting procedure. However, the constraint is usually obtained initially by the application of an external force at either a specific force-application rate or a specific strain rate. The two methods will produce the characteristic behavior shown in Fig. 1 when the initial stress, σ0, exceeds the proporti...
SCOPE
Note 1: The method of testing for the stress relaxation of plastics has been withdrawn from this standard, and the responsibility has been transferred to Practice D2991.  
1.1 These test methods cover the determination of the time dependence of stress (stress relaxation) in materials and structures under conditions of approximately constant constraint, constant test environment, and negligible vibration. In the procedures, the material or structure is initially constrained by externally applied forces, and the change in the external force necessary to maintain this constraint is determined as a function of time.  
1.2 Specific methods for conducting stress-relaxation tests on materials subjected to tension, compression, bending and torsion stresses are described in Parts A, B, C, and D, respectively. These test methods also include recommendations for the necessary testing equipment and for the analysis of the test data.  
1.3 Bending stress-relaxation tests to determine relaxation properties by using ring-shaped specimens machined from bulk material have been thoroughly developed and widely used to determine stress-relaxation properties (1).2 These tests are outside the scope of these test methods.  
1.4 The long time periods required for these types of tests are often unsuited for routine testing or for specification in the purchase of material. However, these tests are valuable tools in obtaining practical design information on the stress relaxation of materials subjected to constant constraint, constant test environment, and negligible vibration, and in investigations of the fundamental behavior of materials.  
1.5 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.6 This standard does not purport to address all of the safety concerns, if a...

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This guide identifies statistical procedures for use in developing new test methods or revising or evaluating existing test methods, or both. It also cites statistical procedures especially useful in the application of test methods. This standard recommends what approaches may be taken and indicates which standards may be used to perform such assessments.
SIGNIFICANCE AND USE
4.1 The creation of a standardized test method generally follows a series of steps from inception to approval and ongoing use. In all such stages there are questions of how well the test method performs.  
4.1.1 Assessments of a new or existing test method generally involve statistical planning and analysis. This standard recommends what approaches may be taken and indicates which standards may be used to perform such assessments.  
4.2 This standard introduces a series of phases which are recommended to be considered during the life cycle of a test method as depicted in Fig. 1. These begin with a design phase where the standard is initially prepared. A development phase involves a variety of experiments that allow further refinement and understanding of how the test method performs within a laboratory. In an evaluation phase the test method is then examined by way of interlaboratory studies resulting in precision and bias statistics which are published in the standard. Finally, the test method is subject to a monitoring phase.
FIG. 1 Sequence of Steps  
4.3 All ASTM test methods are required to include statements on precision and bias.3  
4.4 Since ASTM began to require all test methods to have precision and bias statements that are based on interlaboratory studies, there has been increased concern regarding what statistical experiments and procedures to use during the development of the test methods. Although there exists a wide range of statistical procedures, there is a small group of generally accepted techniques that are beneficial to follow. This guide is designed to provide a brief overview of these procedures and to suggest an appropriate sequence of conducting these procedures.  
4.5 Statistical procedures often result in interpretations that are not absolutes. Sometimes the information obtained may be inadequate or incomplete, which may lead to additional questions and the need for further experimentation. Information outside the data is also impo...
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1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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Standard Guide for Defining the Test Result of a Test Method

ABSTRACT
The purpose of this guide is to provide guidelines for identifying the elements that comprise the test result of a test method and to illustrate how these elements combine into the test result. It covers the types of measurement scales used for expressing observations and test results. This guide provides information on the construction of test results from more elemental measurements.
SIGNIFICANCE AND USE
4.1 All test methods have an output in the form of a test result. This guide provides information on the construction of test results from more elemental measurements.  
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This guide defines terms and introduces basic methods for probability sampling of discrete populations, areas, and bulk materials. It provides an overview of common probability sampling methods employed by users of ASTM standards. This guide also describes the principal types of sampling designs and provides formulas for estimating population means and standard errors of the estimates.
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4.1 This guide describes the principal types of sampling designs and provides formulas for estimating population means and standard errors of the estimates. Practice E105 provides principles for designing probability sampling plans in relation to the objectives of study, costs, and practical constraints. Practice E122 aids in specifying the required sample size. Practice E141 describes conditions to ensure validity of the results of sampling. Further description of the designs and formulas in this guide, and beyond it, can be found in textbooks (1-10).3  
4.2 Sampling, both discrete and bulk, is a clerical and physical operation. It generally involves training enumerators and technicians to use maps, directories and stop watches so as to locate designated sampling units. Once a sampling unit is located at its address, discrete sampling and area sampling enumeration proceeds to a measurement. For bulk sampling, material is extracted into a composite.  
4.3 A sampling plan consists of instructions telling how to list addresses and how to select the addresses to be measured or extracted. A frame is a listing of addresses each of which is indexed by a single integer or by an n-tuple (several integer) number. The sampled population consists of all addresses in the frame that can actually be selected and measured. It is sometimes different from a targeted population that the user would have preferred to be covered.  
4.4 A selection scheme designates which indexes constitute the sample. If certified random numbers completely control the selection scheme the sample is called a probability sample. Certified random numbers are those generated either from a table (for example, Ref (11)) that has been tested for equal digit frequencies and for serial independence, from a computer program that was checked to have a long cycle length, or from a random physical method such as tossing of a coin or a casino-quality spinner.  
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5.1 Background—In a single laboratory, the limit of quantitation, LOQ, equal to ten times the standard deviation obtained under repeatability conditions extrapolated to zero concentration (s0) based on samples with close to zero concentrations has been recommended.3 A test result at this LOQ has an uncertainty of ±30 % at the 99 % confidence level.  
5.1.1 This practice uses a regression technique to determine a similar limit for a test method (PLOQ) using statistically pooled repeatability standard deviations over multiple operators/laboratories/samples from ILS data. This PLOQ can be used by industry to assess the reliability of a test method, or, compare reliability of different test methods, for quantitative measurement at concentrations near zero. Similarly, quantitative test results obtained using the test method for levels at or below the PLOQ can be expected by industry to have an uncertainty of ±30 % or greater at the 95 % confidence level.  
5.1.2 The regression technique described in this practice can also be used to determine a limit of quantitation specific for a single laboratory (LLOQ). The limit thus quantified for one laboratory is defined by this standard as the laboratory limit of quantitation (LLOQ).  
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1.1 This practice covers the use of standard regression techniques and data from an interlaboratory study to determine a lower quantitative limit for a test method. This determined lower limit represents the numerical limit at or above which the test results are considered to be quantitatively meaningful for commerce or regulatory activities by this practice. It is defined by this standard as the pooled limit of quantitation (PLOQ) for the test method.  
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ASTM E691-23(Practice)
Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

ABSTRACT
This practice describes the techniques for planning, conducting, analyzing, and treating the results of an interlaboratory study (ILS) of a test method. The statistical techniques described in this practice provide adequate information for formulating the precision statement of a test method. This practice is also concerned exclusively with test methods which yield a single numerical figure as the test result, although the single figure may be the outcome of a calculation from a set of measurements. ASTM regulations require precision statements in all test methods in terms of repeatability and reproducibility and knowledge of the test method precision is useful in commerce and in technical work when comparing test results against standard values or between data sources.
SIGNIFICANCE AND USE
4.1 ASTM regulations require precision statements in all test methods in terms of repeatability and reproducibility. This practice may be used in obtaining the needed information as simply as possible. This information may then be used to prepare a precision statement in accordance with Practice E177. Knowledge of the test method precision is useful in commerce and in technical work when comparing test results against standard values (such as specification limits) or between data sources (different laboratories, instruments, etc.).  
4.1.1 When a test method is applied to a large number of portions of a material that are as nearly alike as possible, the test results obtained will not all have the same value. A measure of the degree of agreement among these test results describes the precision of the test method for that material. Numerical measures of the variability between such test results provide inverse measures of the precision of the test method. Greater variability implies smaller (that is, poorer) precision and larger imprecision.  
4.1.2 Precision is reported as a standard deviation, coefficient of variation (relative standard deviation), variance, or a precision limit (a data range indicating no statistically significant difference between test results).  
4.1.3 This practice is designed only to estimate the precision of a test method. However, when accepted reference values are available for the property levels, the test result data obtained according to this practice may be used in estimating the bias of the test method. For a discussion of bias estimation and the relationships between precision, bias, and accuracy, see Practice E177.  
4.2 The procedures presented in this practice consist of three basic steps: planning the interlaboratory study, guiding the testing phase of the study, and analyzing the test result data.  
4.2.1 The planning phase includes forming the ILS task group, the study design, selection, and number of participating laborato...
SCOPE
1.1 This practice describes the techniques for planning, conducting, analyzing, and treating the results of an interlaboratory study (ILS) of a test method. The statistical techniques described in this practice provide adequate information for formulating the precision statement of a test method.  
1.2 This practice does not concern itself with the development of test methods but rather with gathering the information needed for a test method precision statement after the development stage has been successfully completed. The data obtained in the interlaboratory study may indicate, however, that further effort is needed to improve the test method.  
1.3 Since the primary purpose of this practice is the development of the information needed for a precision statement, the experimental design in this practice may not be optimum for evaluating materials, apparatus, or individual laboratories.  
1.4 Field of Application—This practice is concerned exclusively with test methods which yield a single numerical figure as the test result, although the single figure may be the outcome of a calculation from a set of measurements.  
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5.1 This method compares the performance of granular or pelletized activated carbons used in odor control applications, such as sewage treatment plants, pump stations, etc. The method determines the relative breakthrough performance of activated carbon for removing hydrogen sulfide from a humidified gas stream. Other organic contaminants present in field operations may affect the H2S breakthrough capacity of the carbon; these are not addressed by this test. This test does not simulate actual conditions encountered in an odor control application, and is therefore meant only to compare the hydrogen sulfide breakthrough capacities of different carbons under the conditions of the laboratory test.  
5.2 This test does not duplicate conditions that an adsorber would encounter in practical service. The mass transfer zone in the 23 cm column used in this test is proportionally much larger than that in the typical bed used in industrial applications. This difference favors a carbon that functions more rapidly for removal of H2S over a carbon with slower kinetics. Also, the 1 % H2S challenge gas concentration used here engenders a significant temperature rise in the carbon bed. This effect may also differentiate between carbons in a way that is not reflected in the conditions of practical service.  
5.3 This standard as written is applicable only to granular and pelletized activated carbons with mean particle diameters less than 2.5 mm. Application of this standard to activated carbons with mean particle diameters (MPD) greater than 2.5 mm will require a larger diameter adsorption column. The ratio of column inside diameter to MPD should be greater than 10 in order to avoid wall effects. In these cases it is suggested that bed superficial velocity and contact time be held invariant at the conditions specified in this standard (4.77 cm/s and 4.8 s). Although not covered by this standard, data obtained from these tests may be reported as in paragraph 12 along with additional ...
SCOPE
1.1 This test method is intended to evaluate the performance of virgin, newly impregnated or in-service, granular or pelletized activated carbon for the removal of hydrogen sulfide from an air stream, under the laboratory test conditions described herein. A humidified air stream containing 1 % (by volume) hydrogen sulfide is passed through a carbon bed until 50 ppm breakthrough of H2S is observed. The H2S adsorption capacity of the carbon per unit volume at 99.5 % removal efficiency (g H2S/cm3 carbon) is then calculated. This test is not necessarily applicable to non-carbon adsorptive materials.  
1.2 This standard as written is applicable only to granular and pelletized activated carbons with mean particle diameters (MPD) less than 2.5 mm. See paragraph 5.3 if activated carbons with larger MPDs are to be tested.  
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM
ASTM D5818-22(Practice)
Standard Practice for Exposure and Retrieval of Samples to Evaluate Installation Damage of Geosynthetics

SIGNIFICANCE AND USE
5.1 The ability to maintain design function (for example, reinforcement, separation, barrier, etc.) or design properties (for example, tensile strength, chemical resistance, etc.), or both, of a geosynthetic may be affected by damage to the physical structure of the geosynthetic due to the rigors of field installation. The effect of damage may be assessed by analyzing specimens cut from sample(s) retrieved after installation in a representative test section. Analysis may be performed with visual examination or laboratory testing of specimens from the control sample(s), and from the exhumed sample(s).  
5.2 A uniform practice for installing and retrieving representative sample(s) from a test section is needed to assess installation damage using project-specific or generally accepted, representative materials and procedures. Damage of a specific grade and type of geosynthetic under specific installation procedures may be assessed with sample(s) exhumed from a full-scale test section.
SCOPE
1.1 This practice covers standardized procedures for obtaining samples of geosynthetics from a test section for use in assessment of the effects of damage immediately after installation caused only by the installation techniques. The assessment may include physical testing. This practice is applicable to any geosynthetic except those installed between layers of aggregate or soil modified by a binder.
Note 1: The binder would inhibit the retrieval of the geosynthetic without inflicting further damage to the geosynthetic. Other practices may be suitable for retrieving geosynthetics used in these applications but are out of the scope of this practice.  
1.2 This practice is limited to full-scale test sections and does not address laboratory modeling of field conditions. This practice does not address which test method(s) to use for quantifying installation damage.  
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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    3 pages
    English language
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  • Standard
    3 pages
    English language
    sale 15% off