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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard is revision of QB/T 2710-2005 Leather - Physical and mechanical tests - Determination of tensile strength and percentage extension.
In addition to a number of editorial changes, the following technical changes have been made with respect to QB/T 2710-2005:
——The size requirements of the press knives and the test pieces with standard designation in 4.4 are adjusted, with the width of the standard test piece, b1, changed from 25mm to 20mm, which is consistent with the international standard.
——The requirement that "the longitudinal direction of the specimen shall be parallel to the direction of traction during testing" is added in 6.2.1.
——The note on the conversion relationship between the unit (MPa) of tensile strength and N/mm2 is added in 7.1, which is consistent with the international standard;
——In 7.1, 7.2 and 7.3, the expression of test results in the report are adjusted, which is consistent with international standard;
——The accuracy requirements for calculation results are added in 7.1, 7.2 and 7.3, which is consistent with the international standard.
——"7.4 Others” is added;
——The test report is appropriately adjusted for the convenience of application.
This standard has been redrafted and modified in relation to ISO 3376: 2011 Leather - Physical and mechanical tests - Determination of tensile strength and percentage extension. This international standard is based on standard IUP 6 of International Union of Leather Technologists and Chemists Societies (IULTCS).
According to the actual situation of China, the following technical modifications have been made in adoption of ISO 3376: 2011:
——The original ISO standards referenced in "Normative references" are changed to relevant standards of China;
——The requirements for tensile testing machine in 4.1 are simplified according to the practices in China, and the requirement for reference to ISO 7500-1 is canceled.
——"Note" for reference in 5.2 is deleted to avoid misunderstanding in application;
——The requirements for the calculation method and calculation result in "Clause 8 Test report” of the original international standard are adjusted to "Clause 7 Expression of results" for easy understanding and application;
——The test report is appropriately adjusted to conform to the practices in China.
The following editorial changes have also been made in this standard:
——The Foreword in ISO standard is deleted;
——"This international standard" is modified to "this standard";
——The comma "," used as the decimal point is replaced by the decimal point ".";
——The decimal point ".” used as the multiple sign is replaced by “×”.
This standard was proposed by China National Light Industry Council.
This standard is under the jurisdiction of SAC/TC 252 the National Technical Committee on Leather of Standardization Administration of China.
This standard replaces the previous professional standard QB/T 2710-2005 Leather - Physical and mechanical tests - Determination of tensile strength and percentage extension, which is abolished from the implementation date of this standard.
The previous editions of the standard replaced by this standard are as follows:
——GB 4689.5-1984 (later modified into QB/T 3812.5-1999, with contents unchanged);
——QB/T 3812.5-1999;
——QB/T 2710-2005.
Leather - Physical and mechanical tests -
Determination of tensile strength and percentage extension
1 Scope
This standard specifies a method for determining the tensile strength, elongation at a specified load and elongation at break of leather.
It is applicable to all types of leather.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
QB/T 2706 Leather - Chemical, physical and mechanical and fastness tests - Sampling location (QB/T 2706-2005, ISO 2418:2002, MOD)
QB/T 2707 Leather - Physical and mechanical tests - Sample preparation and conditioning (QB/T 2707-2018, ISO 2419:2006, MOD)
QB/T 2709 Leather - Physical and mechanical tests - Determination of thickness (QB/T 2709-2005, ISO 2589: 2002, MOD)
3 Principle
Determine the force-bearing capability and extension degree of test piece when it is extended at a specified rate till the forces reach a predetermined value or till the test piece breaks.
4 Apparatus
4.1 Tensile testing machine
The tensile testing machine shall meet the following requirements:
——with an accuracy of 1.0;
——the jaws are with an uniform speed of (100±20)mm/min;
——during the test, the specimen does not slip in either jaw by an amount exceeding 1 % of the original jaw separation.
4.2 A means of determining the extension of the test piece
Determination may be made either by monitoring the separation of the jaws or by sensors which monitor the separation of two fixed points on the test piece.
4.3 Thickness gauge
As specified in QB/T 2709.
4.4 Press knives
As specified in QB/T 2707, capable of cutting a test piece to the shape as shown in Figure 1 and to the dimensions as given in Table 1.
Foreword i
1 Scope
2 Normative references
3 Principle
4 Apparatus
5 Sampling and test piece preparation
6 Procedure
7 Expression of results
8 Test report
