Application scope:
This method is applicable to the fatigue test of various types and materials of physical rails under bending load.
General provisions:
1. The rail bending fatigue test is to obtain the fatigue curve and fatigue limit of the rail under alternating stress.
2. During the test, the rails were simply supported on two bearings. The support distance was 1000 mm. The rail head was up and the concentrated load was applied to the midpoint of the span.
3. The radius of the tread of the indenter applying load is 420±5mm. The tread width (vertical to the length direction of the rail) should be greater than the width of the head and the hardness of the head is HRC50-60. The surface finish is not less than △ 4.
4. The rail stress is calculated according to the formula:
B=Pl/4W1
In the formula: P---load applied to the rail 1—the rail support distance W1—the section coefficient of the railhead 5, the load applied to the rail is alternating load, and the stress symmetry cycle coefficient.
6. The number of cycles of the test when the rail is broken shall be calculated from the time when the required load is reached.
7. The rail bending fatigue tester shall be periodically verified by the national measurement department. When checking with the static method, the allowable deviation of the dial of the tester shall not exceed 1%.
8. Rail bending fatigue test The mobile load should be calibrated.
Sample selection:
9. The physical rail specimens should meet the requirements of the first-class product standard. There are special requirements set by the other.
10. All samples shall be taken from the same rail, with no less than ten in each group.
11, the length of the sample is 1150 persons 50 mm.
12. There shall be no defects on the appearance of the specimen. Those who have conditions shall conduct inspections.
Tests and results:
13, the highest stress value to fatigue limit test stress value of not less than six.
14. The stress value of the first sample is taken to be 0.2}-0.4 times the ultimate strength of the rail steel. The subsequent stress shall be reduced or increased according to the number of cycles when the former stress causes the specimen to fracture, and its amplitude shall not exceed 3 kg. /mm z, the last two stress differences (ie close to the fatigue limit) shall not be greater than 1 kg/mm.
15. Determine the fatigue limit of the rail with a base of 2 million times.
16. It is not permissible to use specimens that have been tested but not fractured to retest under another stress.
17. The test data of the test specimens that have been stopped halfway during the test may only be used as a reference. They are indicated by appropriate symbols in the drawings.
18. The test result must be calibrated by the tester after calibration. The test data was organized by least squares method, and the fatigue curve diagram was plotted in Cartesian coordinates. The ordinate axis in the figure represents the stress (kg/mm), and the axis of abscissa represents the logarithm of the cycle number N (1gN). The fatigue limit is determined from the fatigue curve or the fatigue curve equation.
For specific details, please contact the Technical Department of Jinan Zhongchuang Industrial Test System Co., Ltd.
This method is applicable to the fatigue test of various types and materials of physical rails under bending load.
General provisions:
1. The rail bending fatigue test is to obtain the fatigue curve and fatigue limit of the rail under alternating stress.
2. During the test, the rails were simply supported on two bearings. The support distance was 1000 mm. The rail head was up and the concentrated load was applied to the midpoint of the span.
3. The radius of the tread of the indenter applying load is 420±5mm. The tread width (vertical to the length direction of the rail) should be greater than the width of the head and the hardness of the head is HRC50-60. The surface finish is not less than △ 4.
4. The rail stress is calculated according to the formula:
B=Pl/4W1
In the formula: P---load applied to the rail 1—the rail support distance W1—the section coefficient of the railhead 5, the load applied to the rail is alternating load, and the stress symmetry cycle coefficient.
6. The number of cycles of the test when the rail is broken shall be calculated from the time when the required load is reached.
7. The rail bending fatigue tester shall be periodically verified by the national measurement department. When checking with the static method, the allowable deviation of the dial of the tester shall not exceed 1%.
8. Rail bending fatigue test The mobile load should be calibrated.
Sample selection:
9. The physical rail specimens should meet the requirements of the first-class product standard. There are special requirements set by the other.
10. All samples shall be taken from the same rail, with no less than ten in each group.
11, the length of the sample is 1150 persons 50 mm.
12. There shall be no defects on the appearance of the specimen. Those who have conditions shall conduct inspections.
Tests and results:
13, the highest stress value to fatigue limit test stress value of not less than six.
14. The stress value of the first sample is taken to be 0.2}-0.4 times the ultimate strength of the rail steel. The subsequent stress shall be reduced or increased according to the number of cycles when the former stress causes the specimen to fracture, and its amplitude shall not exceed 3 kg. /mm z, the last two stress differences (ie close to the fatigue limit) shall not be greater than 1 kg/mm.
15. Determine the fatigue limit of the rail with a base of 2 million times.
16. It is not permissible to use specimens that have been tested but not fractured to retest under another stress.
17. The test data of the test specimens that have been stopped halfway during the test may only be used as a reference. They are indicated by appropriate symbols in the drawings.
18. The test result must be calibrated by the tester after calibration. The test data was organized by least squares method, and the fatigue curve diagram was plotted in Cartesian coordinates. The ordinate axis in the figure represents the stress (kg/mm), and the axis of abscissa represents the logarithm of the cycle number N (1gN). The fatigue limit is determined from the fatigue curve or the fatigue curve equation.
For specific details, please contact the Technical Department of Jinan Zhongchuang Industrial Test System Co., Ltd.
1. All natural granite of high precision machine tool bed, beam, shock absorption is higher.
2. Completely closed housing, outer circulation type cutting fluid additive, equipped with a box to collect debris, ensure a clean, neat machining site.
3. X.Y.Z three-axis use high precision imported linear guide rail super rectangle, load bearing capacity, high precision fast positioning.
4. Suitable for electronics, mobile phone fittings of high speed and high light cutting edge chamfering and medical device
CNC Stamp Engraving Machine,Laser Engraving Rubber Stamps,Stable Stamp CNC Engraving Machine,Precision CNC Engraver Machine
Jiangsu Changzhou Jinghua Numerical Control Equipment Co.,Ltd. , https://www.jkengraving.com