• Follow us
Home > Knowledge > Content
Technical conditions for the manufacturing and acceptance of elastic cushioning pads under iron gaskets.
Jan 30, 2018

1 scope

Technical requirements, test methods, inspection rules, marking and packing and storage and transportation of the elastic gaskets under iron gasket are provided in this technical condition.

The technical conditions are applicable to the elastic gasket under the wj-8 elastic iron gasket (hereinafter referred to as the elastic plate).

Normative reference documents.

The terms and conditions in the following documents shall be subject to the terms of this technical condition.

All dated reference documents, its all subsequent modification single (not including errata content) or revision shall not apply to the technical conditions, however, according to the technical conditions to reach an agreement of the parties are encouraged to study whether can use the latest version of these documents.

The latest version of a reference document which is not dated is applicable to this technical condition.

GB/T 10654

The determination of tensile strength and elongation of high polymer porous elastic materials.

GB/T10653

Porous elastic material of high polymer - determination of compression permanent deformation.

GB/T3512

Vulcanized rubber or thermoplastic rubber hot air accelerated aging and heat resistance test.

GB/T2626

Rubber gasket under railway concrete sleeper.

GB/T1690

Test method for abrasion resistance of vulcanized rubber.

ASTMD1044

Test method for wear resistance of plastic surface.

GB/T1043

Test method for impact test of rigid plastic beam.

GB/T 2828.1

Count sampling inspection procedure part 1: sampling plan for batch inspection by the receiving quality limit (AQL).

3 technical requirements

3.1 raw materials

The gasket is the elastomer gasket of the microporous foaming structure, and the physical properties of the raw material should be in accordance with the relevant regulations.

3.2 dimensional accuracy

The type size of the washboard shall conform to the requirements of the design drawing.

3.3 appearance

3.3.1 the plate should be smooth and trim, and there is no shortage of corners.

The margin is not greater than 1mm.

3.3.2 one or two surfaces of the pad can be trimmed, polished or retained to remove the worn appearance.

3.3.3 the lack of glue area caused by impurities, bubbles, water lines and sulks in two working faces is not greater than 6mm2,

The depth shall not be greater than 0.5mm, and each working face shall not exceed three.

3.4 physical properties

The physical properties of the pads shall be in accordance with the provisions of table 1.

Table 1 physical and mechanical properties of elastic gaskets.

The serial number

project

unit

indicators

1

The tensile strength

Before the aging

MPa

≥ 4.0

After aging

MPa

≥ 3.4

2

Pull out the elongation.

Before the aging

%

≥200

After aging

%

≥170

3

Compression permanent deformation

%

≤ 20

4

Working resistance

Ω

≥ 109

5

Oil-resistant volume expansion rate.

(46# engine oil, 72 hours later)

%

≤ 5

6

Surface Taber abrasion.

Mg/1000turn

≤ 6

7

Low temperature impact strength(-70℃,4 h)

KJ/m2

≥ 30

3.5 the static stiffness

The static stiffness of type A gaskets should be 35 (plus or minus 5) KN/mm;

The static stiffness of type B gaskets should be 25 (-5 ~ 0) KN/mm.

3.6 dynamic stiffness ratio.

The dynamic stiffness ratio should not be greater than 1.5.

3.7 fatigue performance

After 3 million fatigue tests, the pad shall not crack, the permanent deformation shall not be greater than 10%, and the change rate of static rigidity shall not exceed 20%.

4 test methods

4.1 raw material test

The raw material test of the washboard is carried out according to relevant regulations.

4.2 dimensional accuracy check.

The dimension precision of the pad is checked by universal measuring tool.

4.3 appearance inspection

The surface of the washboard is inspected with visual and universal gauges.

4.4 physical performance test.

4.4.1 tensile strength and tensile elongation test.

The tensile strength and elongation test of the gasket were carried out according to GB/T 10654.

Each block

Six samples were tested, three of which were tested for pre-aging performance, and three were tested for post-aging performance.

Aging test shall be conducted in accordance with GB/T 3512, aging condition is: 100 + 2 ℃, 96 h.

4.4.2 compression permanent deformation test.

The compression permanent deformation test of the pad is carried out according to GB/T10653.

Six samples were taken for each of the pads, which were divided into two groups for testing.

Test conditions for: 70 + / - 1 ℃, 22 h, 30% compression,

4.4.3 work resistance test.

The working resistance test of the pad is carried out in accordance with the provisions of TB/T2626.

4.4.4 oil-proof test.

The oil resistance test of the gasket is carried out according to GB/T1690.

Test medium for 46 # engine oil, test conditions for 23 + 2 ℃, soaked in oil 72 h.

4.4.5 surface abrasion test.

The surface Taher abrasion test of the pad was carried out according to ASTM D1044.

4.4.6 low temperature impact strength test.

Intercept from the plate, sample length is 15 mm, 12 mm width, thickness of plate thickness, samples at 70 ℃ in dry ice and ethanol mixed solution of 4 h state regulation.

The impact strength test was carried out according to the provisions of GB/T1043, and the test support line was 70mm across, and the extraction and testing work from the low temperature state should be completed within 15s.

4.5 static stiffness test.

The static stiffness test of the pad is carried out according to appendix A.

4.6 dynamic stiffness ratio test.

The static stiffness test was carried out after the static stiffness test was completed and the dynamic stiffness test was carried out according to the provisions of appendix B.

The stiffness ratio.

4.7 fatigue test.

The fatigue performance test of the pad is carried out according to appendix C.

5 inspection rules

Washboard inspection is divided into factory inspection and type inspection.

The factory inspection shall not be more than 10,000 units, inspection.

The contents are 5.1 ~ 5.4.

In case of any of the following situations, the gasket shall be inspected in type 5.1 ~ 5.6.

A) when the factory goes into production for the first time;

B) changes in materials, designs, structures or processes;

C) normal production per year;

D) when the production is resumed after six months;

E) when the user disagrees.

5.1 dimensional accuracy

Plate size accuracy should meet the requirements of article 3.2, according to GB/T2828.1 inspection rules, ordinal sampling, inspection level Ⅰ, breakdown receive quality limit (AQL) of 2.5.

5.2 appearance

The appearance of the washboard shall meet the requirements of 3.3, and the inspection rules shall be according to GB.

T 2828.1, a sampling inspection level Ⅰ, receiving quality limit (AQL) of 4.0.

5.3 physical properties

Each of the three pads were randomly selected for each test, and the test results should meet the requirements of 3.4.

5.4 the static stiffness

The static stiffness of the pad shall meet the requirements of 3.5. The inspection rule shall be sampled at the same time as GB/T2828.1.

Test level s-1, receiving quality limit (AQL) is 2.5.

5.5 dynamic stiffness ratio.

The test results should meet the requirement of 3.6.

5.6 fatigue performance

The test results should meet the requirements of 3.7.

6 service life

The service life of the pad is not less than 8 years or the total weight is not less than 600 million tons.

7 logo and packaging

7.1 elastic gaskets shall have obvious permanent plant marks, product marks and year marks of manufacture.

7.2 elastic gasket (box) is firmly packed and weighs no more than 30kg.

The package shall not be damaged during normal transportation. Each bag (box) shall be accompanied by a factory inspection certificate.

7.3 the packaging of the elastic gasket shall be marked with packaging, and the packing mark shall include the following contents:

A) product name;

B) specifications and models;

C) the number;

D) weight;

E) manufacturer's name;

F) manufacture batch number;

G) date of manufacture.

8 storage and transportation

The elastic gasket shall be stored in a clean, ventilated, non-direct sunlight, away from heat source and chemical reagent contamination.

The storage period is one year.

During the storage period, the performance indexes of the elastic gasket shall not be lower than the technical conditions.

In the process of transportation, the elastic plate is strictly prohibited to contact with the chemical drugs such as oil and organic solvents, and should prevent exposure.

Appendix A test of static rigidity of elastic cushion.


A. are above 1

The test method for determining the static stiffness of elastic cushion is described in this appendix.

A.2 symbols and definitions.

F1 -- the minimum load applied to the measured elastic cushion, 20 kN;

F2 - maximum load applied to the measured elastic cushion, 70 kN;

D1 -- displacement of the measured elastic cushion in the loading to F1, mm;

D2 -- the displacement of the measured elastic cushion in loading to F2, mm;

KSTA -- static stiffness, kN/mm.

A. 3 original reason

The displacement of the elastic cushion under load is measured by applying vertical load to the elastic cushion.

A. 4 equipment

A. 4.1 testing machine

Adopt 200kN or 300kN universal material testing machine.

The accuracy is 500N, and the value of the indicator is not greater than l %.

A.4.2 the force port is loaded with 6 gantry plates.

1) the static rigidity test of the elastic cushion under the orbit shall have the same width as the width of 60kg/m rail rail, and the length of the elastic cushion shall be no less than the loading steel plate with the length of the elastic cushion and the thickness not less than 25mm.

It can also be used to replace the loading steel plate of 60kg/m short rail with length greater than the length of the elastic cushion.

2) the static rigidity test of the elastic cushion under the iron pad adopts the loading steel plate with the same width and length as the iron plate, and the thickness is no less than 40mm.

A.4.3 support plate.

1) the static rigidity test of the elastic cushion under the rail adopts the flat steel plate with the same width and length as the measured elastic cushion.

2) the static rigidity test of the elastic cushion under the iron cushion is not less than the width and length of the elastic cushion.

A. 4.4 emery cloth

The grain size of sand is 45-751lm.

A.4.5 displacement tester.

A percentage table or other displacement meter that can measure the vertical displacement of the measured elastic cushion and the measurement accuracy of 0.0 LMM.

A.5 test steps

Test temperature is 20 + / - 5 ℃

Before experiment, experiment with all components and equipment in 20 + / - 5 ℃ environment let stand for at least 24 h.

Laid test rig test machine, placed order: bearing plate, emery cloth, elastic pad to be tested, emery cloth, load, the steel plate (or short rail), to ensure that the loading plate (or short rail) placed on the measured elastic cushion on the work area.

The displacement of the loading steel plate (or short rail) is determined by two displacement tester at the Angle of the steel plate (or short rail).

Preloading 140kN, unloading, stopping 10s, loading 140kN again, unloading, and then formally testing.

At the beginning of the formal test, the two displacement testers were set to zero and then loaded uniformly at a speed of 2 ~ 3 kN/s.

When the load is added to F1 and F2, each stop for l min, and the displacement D1 and D2 of loading steel plate (or short rail) are recorded respectively.

The average value of D1 and D2 is calculated three times.

The static stiffness is calculated with the following formula.

KSTA = (F2 - F1)/(- D1, D2)

A.6 test report

The test report shall include at least the following:

A) the name, model and description of the elastic cushion;

B) sample source;

C) name and address of the laboratory;

D) test method;

E) date of completion of the test;

F) test results;

G) testers and technical leaders.

Appendix B dynamic stiffness test of elastic cushion.

B. are above 1

The test method for determining dynamic stiffness of elastic cushion is described in this appendix.

B.2 symbols and definitions.

Fl -- the minimum load applied to the measured elastic cushion, 20kN;

F2 - maximum load applied to the measured elastic cushion, 70kN;

F alpha 1 -- the actual minimum load applied to the measured elastic cushion, kN;

F alpha 2 -- the actual maximum load applied to the measured elastic cushion, kN;

D1 -- the minimum displacement of the elastic cushion, mm;

D2 -- the maximum displacement of the elastic cushion measured, mm;

KDYN -- dynamic stiffness, kN/mm.

B. three principles

The maximum and minimum displacement on the surface of the elastic cushion is measured by applying the periodic vertical load to the elastic cushion at constant frequency.

B. 4 equipment

B. 4.1 testing machine

The test machine can produce 95kN load at (7-9)Hz frequency.

B.4.2 loading steel plates.

1) the dynamic stiffness test of the elastic cushion under the orbit shall have the same width as the width of 60kg/m rail rail, and the length of the elastic cushion shall not be less than the loading steel plate with the length of the elastic cushion and the thickness not less than 25mm.

It can also be used to replace the loading steel plate of 60kg/m short rail with length greater than the length of the elastic cushion.

2) the dynamic stiffness test of the elastic cushion under the iron gasket adopts the loading steel plate with the same width and length as the iron plate, and the thickness is no less than 40mm.

B.4.3 support plate.

1) the dynamic stiffness test of the elastic cushion under the rail adopts the flat steel plate with the same width and length as the measured elastic cushion.

2) the dynamic stiffness test of elastic cushion under the iron cushion is not less than the width and length of the elastic cushion.

B. 4.4 emery cloth

The grain size of sand is 45-75 mu m.

B.4.5 displacement tester.

The device can measure the vertical displacement and measurement accuracy of the measured elastic cushion under the (7-9)Hz frequency.

B.4.6 load measuring instrument.

The instrument can be used to measure the load and measurement accuracy of + 0.3kn at (7-9)Hz frequency.

B.4.7 recording equipment.

At sampling frequency 50 Hz can be used to record and print out the displacement and load of the equipment.

B.5 test procedures

Test temperature is 20 + / - 5 ℃

Before experiment, experiment with all components and equipment in 20 + / - 5 ℃ environment let stand for at least 24 h.

The test equipment is placed on the test machine, and the order is: supporting steel plate, sand cloth, elastic cushion, emery cloth, loading steel plate (or short rail).

Ensure that the loading plate (or short rail) is placed on the area where the elastic cushion is measured.

Load cycle load 20kN ~ 70kN, loading frequency (8 + + 1)Hz, load cycle 1000 times.

In the last 100 load cycles, the displacement of the actual loading and loading of the steel plate (or short rail) in 10 cycles is recorded.

Calculate the average value of F alpha 1, F alpha 2, D1 and D2.

The dynamic stiffness is calculated with the following formula.

KDYN = alpha 2 - alpha 1 F (F)/(- D1, D2)

B.6 test report

The test report shall include at least the following:

A) the name, model and description of the elastic cushion;

B) sample source;

C) name and address of the laboratory;

D) test method;

E) date of completion of the test;

F) test results;

G) testers and technical leaders.

Appendix C test of static stiffness of the system node.

C. are above 1

This appendix describes the test method of static stiffness of the fastener system.

C.2 symbols and definitions.

Fl -- the minimum load applied to the steel rails of the tested system is taken as 5kN;

F2 -- maximum load applied to the steel rail of the tested system, 55kN;

F alpha 1 -- the actual minimum load applied to the steel rail of the tested system, kN:

F alpha 2 -- the actual maximum load applied to the steel rail of the measured system, kN;

DS1 -- the displacement of the steel rail at slow loading to the body 1, mm;

DS2 -- the displacement of the rail during the slow loading to lu2, mm;

D1 -- minimum displacement of rail in dynamic load, mm;

D2 -- maximum displacement of rail in dynamic load, mm;

KSAT -- node static stiffness, kN/mm.

KDYN -- node dynamic stiffness, kN/mm.

C. 3 principle

1) static stiffness:

To the assembly of rail fastening system through testing machine (single support rail assembly) applied perpendicular to the sleeper or no ballastless track unit load levels, determination of rails under the action of load displacement.

2) dynamic stiffness:

Assembly via the tester at a constant frequency of rail fastening system (single support rail assembly) applied perpendicular to the sleeper or no ballastless track unit level cyclic loading, determination of rail under the load of minimum and maximum displacement.

C. 4 equipment

C. 4.1 testing machine

The test machine can produce 95kN load and static load up to 150kN load at (7-9)Hz frequency.

C.4.2 displacement tester.

The instrument can be used to measure the vertical displacement and measurement accuracy of the system at the (7-9)Hz frequency.

C.4.3 load measuring instrument.

The instrument can be used to measure the load and measurement accuracy of + 0.3kn at (7-9)Hz frequency.

C.4.4 recording equipment.

When sampling frequency is 50Hz, it can do digital recording and print out the displacement and load of the equipment.

C.5 test steps

C. 5.1 test environment temperature is 20 + / - 5 ℃.

C. 5.2 before the test, the use of all parts and devices in 20 + / - 5 ℃ environment let stand for at least 24 h.

C.5.3 the entire fasteners system shall be installed in the sleeper or ballastless track unit with a length of about 500mm in support of the flat level.

C.5.4 assembly static stiffness test.

Preloading 100kN, unloading;

Stop 10s, load 100kN again, uninstall, and then formally test.

At the beginning of the formal test, the displacement of the tester is zero, then at a speed of 2 ~ 3 kn/s uniform load, when load to F1 and F2 at each stop lmin, and record the load displacement of rail Dsl, Ds2.

The average value of DS1 and DS2 was calculated three times.

The static stiffness is calculated with the following formula.

KSTA = (F2 - F1)/(DS1 DS2 -)

C.5.5 assembly dynamic stiffness test.

Apply cyclic loading F1 ~ F2, load frequency (8 + + 1)Hz, and load cycle 1000 times.

In the last 100 load cycles, the actual load and displacement of 10 cycles are recorded.

Then, the average value of F alpha 1, F alpha 2, D1 and D2 (mean maximum displacement) is calculated.

The dynamic stiffness is calculated with the following formula:

KDYN = alpha 2 - alpha 1 F (F)/(- D1, D2)

C.6 test report

The test report shall include at least the following:

A) the name, model and description of the system of the test coupler;

B) sample source;

C) name and address of the laboratory;

D) test method;

E) date of completion of the test;

F) test results;

G) testers and technical leaders.