TB/T 3541.3-2018 English PDF (TB/T3541.3-2018)

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TB/T 3541.3-2018: Disk brakes for rolling stock. Part 3: Composite brake pads
TB/T 3541.3-2018
TB
RAILWAY INDUSTRY STANDARD OF
THE PEOPLE’S REPUBLIC OF CHINA
ICS 45.060
S 33
Replacing TB/T 3344-2014, TB/T 3118-2005
Disk brakes for rolling stock - Part 3: Composite brake pads
ISSUED ON: DECEMBER 25, 2018
IMPLEMENTED ON: JULY 01, 2019
Issued by: National Railway Administration
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Technical requirements ... 7
5 Inspection method ... 10
6 Inspection rules ... 12
7 Marking, packaging, transportation and storage ... 14
Appendix A (Normative) Structure and size of brake pads ... 16
Appendix B (Normative) Permissible range of friction coefficient of brake pads ... 20
Appendix C (Normative) Brake pad dovetail inspection gauge ... 23
Appendix D (Normative) Brake friction and wear performance test ... 25
References ... 33
Disk brakes for rolling stock - Part 3: Composite brake pads
1 Scope
This Part of TB/T 3541 specifies the terms and definitions, technical requirements,
inspection methods, inspection rules, marking, packaging, transportation and storage of
composite brake pads for locomotives and rolling stock (hereinafter referred to as brake
pads).
This Part applies to composite brake pads for rolling stocks, which have a maximum
operating speed of no more than 200 km/h and an axle weight of no more than 21 t, or
a maximum operating speed of no more than 120 km/h and an axle weight of no more
than 30 t (hereinafter referred to as rolling stock brake pads); it also applies to the
composite brake pads for railway vehicles, which have a maximum operating speed of
no more than 160 km/h and an axle weight of no more than 18 t (hereinafter referred to
as railway vehicle brake pads).
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB/T 1033.1 Plastics - Methods for determining the density of non-cellular plastics
- Part 1: Immersion method, liquid pycnometer method and titration method (GB/T
1033.1-2008, ISO 1183-1:2004, IDT)
GB/T 1041 Plastics - Determination of compressive properties (GB/T 1041-2008,
ISO 604:2002, IDT)
GB/T 1043.1 Plastics - Determination of Charpy impact properties - Part 1: Non-
instrumented impact test (GB/T 1043.1- 2008, ISO 179-1:2000, IDT)
GB/T 2918 Plastics - Standard atmospheres for conditioning and testing (GB/T
2918-1998, ISO 291:1997, IDT)
GB/T 3398.1 Plastics - Determination of hardness - Part 1: Ball indentation method
(GB/T 3398.1-2008, ISO 2039-1:2001, IDT)
GB/T 3398.2 Plastics - Determination of hardness - Part 2: Rockwell hardness
(GB/T 3398.2-2008, ISO 2039-2:1987, IDT)
4 Technical requirements
4.1 Structure and dimensions
4.1.1 The brake pad consists of a steel back and a friction body; the friction body
consists of a bonding material, a reinforcing material, a friction material.
4.1.2 The structure and dimensions of the brake pad shall comply with the provisions
of Appendix A.
4.2 Appearance
4.2.1 The steel back shall not have cracks or other defects that may cause the brake pad
to break during use.
4.2.2 The friction surface shall be flat. The friction body shall not have inclusions,
cracks, blistering, bulging, delamination, looseness, warping and other defects.
4.2.3 The friction body and the steel back shall be firmly bonded.
4.3 Usage requirements
Under normal use conditions, the following requirements shall be met:
a) The brake pad shall maintain its brake friction performance in accordance with
the requirements specified in this standard.
b) The brake pad shall not break; it shall not produce deformation that affects
disassembly. The friction body shall not fall off; there shall be no peeling or
falling pieces exceeding 10% of the friction area. The friction surface shall not
have defects such as bulges and ablation.
c) The brake pad shall not cause groove wear or plow-shaped wear on the friction
surface of the brake disc. The brake pad's friction surface shall not produce metal
inlays that cause damage to the above-mentioned brake disc or affect the brake
friction and wear performance.
d) The brake pad shall not cause hot spots, thermal peeling, thermal cracks that may
cause the brake disc to break on the friction surface of the brake disc.
4.4 Physical and mechanical properties of friction body
The physical and mechanical properties of the brake pad's friction body shall comply
with the provisions of Table 1.
exceed ±15% of the average friction coefficient, in the normal temperature dry state
and the same braking conditions.
4.5.3.3 The average friction coefficient of the continuous emergency braking stop, or
the average friction coefficient of the stop condition immediately after continuous
braking, shall not exceed ±15% of the average friction coefficient in the normal
temperature dry state and the same braking conditions.
4.5.4 Instantaneous friction coefficient of continuous braking
The instantaneous friction coefficient after 2 minutes of braking shall be within the
range of 0.25 ~ 0.5; the difference between the maximum and minimum values shall
not exceed 0.15.
4.5.5 Static friction coefficient
The static friction coefficient of the rolling stock brake pads shall not be less than 0.35;
the static friction coefficient of the railway vehicle brake pads shall not be less than
0.33.
4.5.6 Wear
The wear of rolling stock brake pads shall not exceed 0.8 cm3/MJ; the wear of railway
vehicle brake pads shall not exceed 1.0 cm3/MJ.
4.5.7 Brake pad status
When various prescribed procedure tests are carried out on a 1:1 brake power test bench,
the brake pads shall be able to withstand a temperature of 400 °C measured on the brake
disc; the brake pads shall not produce transverse through cracks or visible metal inlays;
the friction material shall not burn, melt or leave deposits on the brake disc, nor shall it
produce other defects specified in 4.3.
4.6 Materials and manufacturing
4.6.1 The friction body shall not be made of asbestos, lead, zinc or their compounds, or
other materials that may endanger human health, or materials that may release harmful
dust, fibers, particles or gases during use. The friction body shall not contain asbestos
components; the content of lead, zinc and other components shall not exceed the limit
values specified in GB 5085.3-2007.
4.6.2 The friction body shall not use or contain materials, components and impurities
that may damage the brake disc or increase the wear of the brake disc.
4.6.3 The various components that constitute the friction body of the brake pad shall be
evenly distributed.
Rockwell hardness shall be tested by the method specified in GB/T 3398.2. For
materials with a hardness greater than 100 HRX, the R scale shall be selected. For
materials with a hardness less than 30 HRR, a non-standard X scale is used, that is, the
indenter uses a polished steel ball with a diameter of 19 mm ± 0.015 mm and a Vickers
hardness of not less than 7 MN/mm2.
5.3.3.3 The distance between adjacent indentation edges or between the indentation
edge and the specimen edge shall not be less than 10 mm.
5.3.3.4 Test 5 points on any surface of each specimen; take the average value of the test
results at each point as the pad hardness value.
5.3.3.5 If the specimen has an indentation crack during the test, the test data is invalid.
5.3.4 Impact strength
The test is carried out in accordance with the provisions of GB/T 1043.1. Use a notched
specimen, which has a span of 40 mm and uses the thickness direction as the impact
loading direction.
5.3.5 Compression strength and compression modulus
The test is carried out in accordance with the provisions of GB/T 1041. The test speed
is 1 mm/min; the speed tolerance is ±20%.
5.4 Braking friction and wear performance
5.4.1 The braking friction and wear performance test shall be carried out on a 1:1
braking power test bench, according to the procedure specified in Appendix D.
5.4.2 The brake pads used for the test shall be unused real objects; the reduced-scale
specimens shall not be used for the test.
5.4.3 The test under humidification conditions shall be carried out using a water spray
device.
5.5 Hazardous substances
5.5.1 The content of asbestos in the brake pads shall be tested according to the method
specified in GB/T 23263-2009.
5.5.2 The content of lead and zinc in the brake pads shall be tested according to the
method specified in GB 5085.3-2007.
6 Inspection rules
6.1 Inspection classification and inspection items
6.3.1 Type inspection shall be carried out in the following cases:
a) Before the new product is finalized or produced for the first time;
b) When the structure, main components, formula or manufacturing process of the
brake pad changes, which may affect the product performance;
c) When the production of composite brake pads and brake shoes is resumed after
all products have been discontinued for 2 years;
d) When the production location is changed;
e) When the product performance and quality consistency cannot be proved after 5
years of continuous production.
6.3.2 When inspecting the brake friction and wear performance, if one of the test results
does not meet the requirements of this standard, it can be re-inspected with double
quantity of samples. If the re-inspection result is still unqualified, the brake friction and
wear performance is unqualified.
7 Marking, packaging, transportation and storage
7.1 Marking
The back of the brake pad shall have a permanent mark; the handwriting shall be clear,
which shall still be recognizable when the brake pad is used to the end of its use. The
content of the mark is as follows:
a) Brake pad model;
b) Name or code of the manufacturer;
c) Year and month of manufacture or batch number.
7.2 Packaging
7.2.1 The brake pads shall be packaged and moisture-proof. The following marks shall
be on the packaging box:
a) Name and model of the brake pad;
b) Name of the manufacturer;
c) Transportation requirement mark.
7.2.2 The packaging box shall contain the product certificate and the inspection report
required by the user.