Flexural strength is a measure of the maximum load that a material can withstand when it is bent by an external force. Its value is the magnitude of the normal stress on the cross section when the sample is bent and broken. GB 3074.1-1982 Determination of Flexural Strength of Graphite Electrodes GB3074.1-1982 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Method for the determination of the flexure strengthof graphite electrodes
1 Definition
621.35.035.2
661.666.2
GB 3074.1—82
Flexural strength is a measure of the maximum load that a material can withstand when it is bent by an external force. Its value is the magnitude of the normal stress on the cross section when the specimen is bent and fractured.
2 Instruments and equipment
2.1 Material testing machine: range 0～5000N, accuracy 2.5N. 2.2 Four-point method is used for loading. For electrodes with a diameter greater than or equal to 300mm, the spacing between the upper indenters is 40mm, the radius of curvature of the indenter is 5mm, the spacing between the lower indenters is 120mm, and the radius of curvature of the indenter is 3mm. For electrodes with a diameter less than 300mm, the spacing between the upper pressure heads is 35mm, the radius of curvature of the pressure heads is 5mm, the spacing between the lower pressure heads is 105mm, and the radius of curvature of the pressure heads is 3mm. The lower support plate is supported by steel balls. As shown in the figure. 4120(B105）
440（B35）
A20(B10 2
2.3 Vernier caliper: Measuring range 0～200mm, accuracy 0.02mm. 3 Sample
Upper support platebzxz.net
Upper pressure head
Lower pressure head
Working support plate
Supporting steel speed
3.1 Size: For electrodes with a diameter greater than or equal to 300mm, the sample size is 20mm in diameter and 160mm in length; for electrodes with a diameter less than 300mm, the sample size is 10mm in diameter and 120mm in length. The processing accuracy is ±0.1mm. 3.2 Requirements: Half line is not more than 0.1mm/100mm, and the smoothness reaches √6. There are no visible cracks or flaws on the surface of the sample. 3.3 Sampling position: Take a piece of bad material parallel to the extrusion direction at the center of the end of the electrode to be tested and process it into a sample. 3.4 Quantity: Take 6 electrodes per furnace (two electrodes in the middle and two ends of the furnace core). Issued by the General Administration of Standards of the People's Republic of China on May 10, 1982
Implementation on March 1, 1983
4 Test steps
GB 3074.1—82
4.1 The sample must be baked in a drying oven at 110℃ for 2h, stored in a desiccator, and cooled to room temperature for use. 4.2 Measure the sample size with a vernier caliper and record the data. 4.3 Align the center of the sample with the center of the upper pressure head spacing, and make the axial directions of the upper and lower pressure heads perpendicular to the sample axis. 4.4 Adjust the no-load speed of the testing machine to 1.5mm/min, then load until the sample breaks, and record the maximum load. 5 Calculation formula
The sample flexural strength o (kg/cm2) is calculated according to the following formula: accurate to one decimal place.
Formula: o-
6 Test report
-Flexural strength, kg/cm2,
Maximum load, kg;
-Distance between pressure head and fulcrum, cm,
Specimen diameter, cm.
The test report should include the following contents:
Sample number, specification and source.
Specimen flexural strength and its average value.
Additional remarks:
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by Shanghai Carbon Factory. The main drafter of this standard was Yang Shugen.
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