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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 3960-1983 Test method for friction and wear of plastics by sliding. The following main changes have been made with respect to GB/T 3960-1983:
——The description of the object to be standardized is added (see Clause 1);
——The clause - “Normative references” is added (see Clause 2);
——Some of the terms and definitions involved in this standard are modified (see 3.1, 3.2, 3.4, 3.7 and 3.9; 1.1, 1.2, 1.3, 1.4 and 1.5 of Edition 1983);
——Some terms and definitions are added in this standard (see 3.3, 3.5, 3.6, 3.8, 3.10 and 3.11);
——The principle for the test method is added (see Clause 4);
——Part of requirements for the test apparatuses used in this standard and the format are modified (see 5.1; 3.1, 3.2, 3.3, 3.4 and 3.5 of Edition 1983);
——Requirements for proving ring are modified (see 6.1; 3.6 of Edition 1983);
——Requirements for specimen are modified (see 6.2; 2.1 and 2.2 of Edition 1983);
——Test conditions for friction and wear are added (see 7.2);
——Test procedures are modified (see 8.1 and 8.2; 6.1 and 6.2 of Edition 1983);
——Representation method of wear loss is added (see 9.2);
——Requirements for significant digits are modified (see 9.5; 7.1.2 of Edition 1983);
——Requirements for the test report are added [see 10a), b), e), g) and h)].
This standard was proposed by the China Petroleum and Chemical Industry Association.
This standard is under the jurisdiction of the Subcommittee on Universal Methods and Products of National Technical Committee on Plastic of Standardization Administration of China (SAC/TC 15/SC 4).
The previous edition of this standard is as follows:
——GB/T 3960-1983.
Plastics - Test method for friction and wear by sliding
1 Scope
This standard specifies the test methods for friction and wear performances of plastics and plastic composite materials by sliding.
This standard is applicable to the determination of friction and wear performances of plastics and plastic composite materials by sliding.
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.
GB/T 2918 Plastics - Standard atmospheres for conditioning and testing (ISO 291, IDT)
GB/T 1033.1-2008 Plastics - Methods for determining the density of non-cellular plastics - Part 1: Immersion method liquid pyknometer method and titration method (ISO 1183-1:2004, IDT)
GB/T 17754-2012 Tribology terminology
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 17754-2012 and the following apply. For the convenience of application, some terms and definitions specified in GB/T 17754-2012 are listed below.
3.1
sliding friction
the friction resisting the sliding motion between contact surfaces of two objects
3.2
friction
the phenomenon and process of resistance to the tangential relative motion or such tendency accompanied by the mechanical energy loss generated between the contact surfaces of two adjacent objects under the action of force
[GB/T 17754-2012, 2.2]
3.3
rubbing pair; tribopair
specially referring to the minimal system composed of two tribological elements in relative motion and interacting with each other
Note: The objects in a rubbing pair are called a counter pair mutually.
[GB/T 17754-2012, 4.4]
3.4
friction force
the tangential force resisting the tangential relative motion between the contact surfaces of two objects while such motion or tendency of one object arises against the other
3.5
friction moment
M
the product of the frictional force borne by the rotating body in the circumferential direction and the effective radius of such body, in the rotating rubbing pair.
[GB/T 17754-2012, 4.38]
3.6
scar width
b
the chord length, in mm, of the concave arc——the section of the damage trace left on the friction surface after friction and wear on the surface of the block, during the ring-block friction and wear test
See Figure 1.
Figure 1 Scar width
3.7
wear
the phenomenon and process of deformation and damage or gradual loss of surface material caused to a surface by friction
[GB/T 17754-2012, 2.3]
3.8
wear loss
the amount of deformation or the loss of the surface material caused to the contact surface of material in a rubbing pair during wear
Note 1: It is generally represented as volume, mass, geometric dimensions, etc.
[GB/T 17754-2012, 5.1]
Note 2: It is represented as volume wear, mass wear and scar width in this standard.
3.9
friction coefficient
μ
the ratio of the friction force to the normal force within a rubbing pair
[GB/T 17754-2012, 4.18]
3.10
methods of lubrication
the methods of providing lubricating medium for a rubbing pair
Note: They can be classified into gap lubrication, continuous lubrication, one-way lubrication, circulating lubrication, etc.
[GB/T 17754-2012, 6.47]
3.11
lubricant
a substance easy to shear that is introduced to reduce friction and control wear between two surfaces in relative motion
[GB/T 17754-2012, 6.48]
4 Principle
The specimen is mounted above the proving ring of the testing machine, with the load applied onto it. The specimen remains stationary and the proving ring rotates at a certain speed. See Figure 2.
Figure 2 Schematic diagram for the test
5 Apparatuses
5.1 Testing machine
5.1.1 Drive system, which is used to drive the circular ring to rotate at the given speed with a relative error of not greater than ±3%, and the radial runout of shaft at the mounting position of the circular ring is less than 0.01mm.
5.1.2 Loading system, which is used to apply normal force on the specimen and the circular ring with a relative error of not greater than ±2%.
5.1.3 The system to measure and record the friction moment with a relative error of not greater than ±3%.
5.1.4 The counter or timer for recording the number of revolutions of the circular ring, with a relative error of not greater than ±1%.
5.1.5 The specimen holder shall ensure that the specimen is free from axial movement after being mounted.
5.2 Balance and measuring tools
5.2.1 The error of the analytical balance shall not be greater than 0.1mg in measurement of the mass of specimen.
5.2.2 The error of the measuring tools shall not be greater than 0.02mm in measurement of the dimensions and scar width of the specimen.
Foreword II
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Apparatuses
6 Proving ring and specimen
7 Test conditions
8 Test procedures
9 Calculation and representation of results
10 Test report
