SH/T 0402-1992 Determination of Tensile Strength of Paraffin Wax

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Card type: Test method

1. Method number / full title / English name / replacement relationship

• Standard number: SH/T 0402-92 (confirmed in 2004)
• Chinese name: Determination of Tensile Strength of Paraffin Wax
• English name: not provided in the available source
• Replacement relationship: replaces ZB E42 005-87
• Adoption relationship: equivalent adoption of the American Society for Testing and Materials standard ASTM D1320-73(83) "Determination of Tensile Strength of Paraffin Wax"
• Approval/implementation: approved by China Petrochemical Corporation 1992-05-20, implemented on 1992-05-20

2. Scope of application and non-applicability

• This standard specifies the method for determining the tensile strength of paraffin wax.
• It is applicable to the determination of the tensile strength of paraffin wax. Its scope of application is paraffin wax with a melting point (determined by the GB/T 2539 method) of 49 to 66℃ (the source source-text extraction is "49[unreadable separator]669C", requires confirmation against the source standard (source-text extraction)), and an elongation not exceeding 3.2 mm.
• It may also be used for other types of paraffin wax, such as blended wax or paraffin wax with a melting point exceeding 66℃, but the elongation of these paraffin waxes should be the same as the above requirements, and there should be no excessive shrinkage during mold cooling.
• The results determined for certain mixtures of paraffin wax and microcrystalline wax cannot be compared with the results of determining crystalline wax by this standard.

3. Method principle

• Tensile strength is the axial stress required to break the cross-section of a representative wax specimen of a specific shape.
• For each sample, a group of six wax specimens is used; the sample is poured into a special mold with a cross-section of 1.6 cm² (the source source-text extraction is "1. 6c.2", requires confirmation against the source standard (source-text extraction)), kept at room temperature 22.8℃±1℃ and relative humidity 50%±5% for 2 h. The tensile strength of the specimen is measured at a loading rate of 89 N/s and expressed in kPa.
• Factors such as the test method and loading rate, the shape of the wax specimen and the size of its cross-section, the preparation method of the wax specimen, the treatment of the wax specimen, the surface condition of the wax specimen, and the internal strain of the wax specimen will all affect the magnitude and accuracy of the test results and must be carefully controlled.

4. Reagents and materials (purity / preparation)

• 5.1 Isooctane: analytical reagent.
• 5.2 Release agent: No. 200 polydimethylsiloxane (1000 mm²/s, 25℃), prepared as a 2% (V/V) isooctane solution.

5. Instruments and equipment

• 6.1 Testing machine: any general-purpose testing machine may be used. To ensure measurement accuracy, it is preferable to use a testing machine with multiple ranges and a maximum load range less than 500 N. The machine is required to be accurate to 1% of the lowest load of the applied force, the applied load must be constant and uniform, the direction of the resultant tensile load must coincide with the longitudinal centerline of the specimen, and it must be capable of rapid and accurate adjustment; the structure of the testing machine must ensure that standard weights can be used to calibrate the entire range used.
• 6.2 Cover plate: rectangular H63 brass structure, length × width × thickness is 57 mm×38 mm×6.4 mm, a brass cover plate is placed on each mold.
• 6.3 Mold: structure is shown in Figure 1, the cross-sectional area of the mold is 1.6 cm² (the source source-text extraction is ".6crnz", requires confirmation against the source standard (source-text extraction)). Figure 1 labels: 4— assembly hole; 2,5— locating pin, 1Cr18Ni9Ti; 3,6— inserted into the locating hole.
• 6.4 Specimen clamp: used to fix the wax specimen on the testing machine, of the general-purpose semi-positioning type, see Figure 2. Correct installation is to install the general-purpose semi-fixed frame shaft between the wax specimen support and the testing machine support. The specimen clamp is divided into upper and lower parts, made of LY 12 hard aluminum (No. 12 forged aluminum). Figure 2 labels: 1— tensile machine connector; 2— general-purpose adjustable center point.
• 6.5 Cooling rack: a base plate for placing the mold, structure as shown in Figure 3.
• 6.6 Base plate: made of 1Cr18Ni9Ti stainless steel narrow strip, width equal to the length of the mold, length equal to 6 times the mold width plus 89 mm, specific dimensions see Figure 3.
• 6.7 Mold spacer: used to evenly separate the molds on the base plate, made of oak, cross-section 12.7 mm×12.7 mm, length equal to the length of the mold.
• 6.8 Water bath: used to treat wax specimens, can be kept constant at 22.8℃±0.3℃ (the source source-text extraction is "22.8℃[unreadable sign]0.390", requires confirmation against the source standard (source-text extraction)), the size of the bath is not specified, but it must be able to hold all wax specimens and be equipped with a floating frame so that all wax specimens can be immersed in water; the bath material is preferably stainless steel.
• 6.9 Thermostatic oven: can maintain a constant temperature up to 100℃±3℃.
• 6.10 Thermometer: for the water bath, use an internal-scale secondary standard thermometer, temperature measurement range -2 to 52℃ (the source source-text extraction is "[unreadable sign]2[unreadable separator]5290", requires confirmation against the source standard (source-text extraction)), minimum division value 0.1℃; the thermometer for stirring paraffin wax is an immersion type, temperature measurement range 0 to 150℃, minimum division value 1.0℃.
• 6.11 Laboratory: should be able to maintain room temperature at 22.8℃±1℃ and relative humidity 50%±5%. Note: For control analysis or research work, the laboratory temperature and relative humidity may be specified separately. However, during the test, the temperature must be maintained not exceeding ±1℃ and the relative humidity not exceeding ±5%; results obtained under different conditions cannot be compared with each other.
• Figure 3 Cooling rack labels: 1— cover plate, 57 mm×38 mm×6.4 mm, H63 brass; 2— mold spacer, 12.7 mm×12.7 mm×121 mm, oak; 3— base plate, 527 mm×121 mm×(thickness source source-text extraction is "M mm", requires confirmation against the source standard (source-text extraction)), 1Cr18Ni9Ti stainless steel.

6. Recommended operating conditions

• Mold placement environment: room temperature 22.8℃±1℃, relative humidity 50%±5%, placed for 2 h±10 min.
• Water bath treatment of wax specimens: 22.8℃±0.3℃ (the source source-text extraction is "22.8℃[unreadable sign][unreadable characters]3℃", requires confirmation against the source standard (source-text extraction)), 15 min.
• Loading rate: 89 N/s.
• Melting wax: heat in thermostatic oven at 100℃±3℃ for 2 h; adjust to 82℃ and hold for 1.5 h; heating rate on electric hot plate 5.6℃/min±1.0℃/min to 110℃±1℃.
• Sample pouring temperature: 110℃±1℃.
• Laboratory: room temperature 22.8℃±1℃, relative humidity 50%±5%.

7. Sampling and specimen preparation

• 7.4.1 Sampling: select a sample sufficient to pour six wax specimens (about 200 g) as one group; these six wax specimens should be taken from different parts of the sample. If the sample is less than 0.45 kg (the source source-text extraction is "0.45 tonnes [source unit uncertain]", requires confirmation against the source standard (source-text extraction)), then the entire sample must be melted; if it is more than 0.45 kg, quartering must be used to obtain a representative sample.
• 7.4.2 Melting wax: place the samples for the six wax specimens to be determined into a clean glass beaker, cover with a clean watch glass, and place in a thermostatic oven already adjusted to 100℃±3℃ and heat for 2 h to melt. Then adjust the thermostatic oven temperature to 82℃ and hold for 1.5 h so that the sample temperature drops to 82℃; at this point remove the beaker from the thermostatic oven, slowly pour the sample into a second clean beaker, and finally leave about 20 mL of sample in the first beaker. Then place the sample in the second beaker on an electric hot plate with an asbestos pad and heat it, stirring slowly with a thermometer during heating, adjusting the heating rate to 5.6℃/min±1.0℃/min until 110℃±1℃. Note: If necessary, reheat the wax at the above heating rate so that the sample temperature reaches 110℃, and filter using industrial filter paper in a funnel with a diameter of 125 mm and a stem of 10 (unit not provided in the available source, requires confirmation against the source standard (source-text extraction)) long.
• While stirring very slowly, carefully adjust the sample temperature to 110℃±1℃, then quickly use a thermometer as a pouring tool to pour the wax into six molds previously placed on the cooling rack, filling as much as possible without overflowing. After pouring the sample, the mold assembly on the base plate must never be disturbed in any way. Record the ambient temperature and relative humidity at the time of pouring. Under conditions of room temperature 22.8℃±1℃ and relative humidity 50%±5%, after 2 h±10 min, carefully remove the specimen from the mold, and before mounting on the testing machine, first immerse it in a water bath at 22.8℃±0.3℃ for 15 min, placing the specimen under the floating frame so that it is completely immersed in water.
• 7.3 Mold preparation: carefully scrape off any wax adhering inside the mold, then wipe clean with a lint-free cloth. Apply a thin layer of release agent to the inside of the mold and to the surfaces of the brass cover plate and stainless steel base plate; use a cotton swab soaked in release agent to apply a very thin layer, then allow the solvent to evaporate. Assemble the mold and wooden spacers on the base plate as shown in Figure 3, and place the brass cover plate at the middle position of the mold. The long end of the cover plate should be perpendicular to the long end of the mold. The cooling rack and mold assembly must be placed on a surface free from vibration. A set of prepared molds should be placed on the cooling rack for at least 1 h before use.

8. Analytical procedure

• 7.1 Calibration: carefully calibrate the tensile strength testing machine so that the direction of the resultant tensile load coincides with the longitudinal centerline of the wax specimen. Calibrate at least once every three months using standard weights with certification certificates; during calibration, select at least four standard weights that conform to the operating range. When selecting standard weights, increase the weight equally to cover the operating range.
• 7.2 Washing glassware: the glassware used in this test should be stored separately and used only for this test. The apparatus must be washed clean to avoid errors caused by contamination. After washing, the apparatus may be heated and dried at a temperature slightly above 100℃.
• 7.5 Mount the specimen firmly and evenly on the specimen clamp, and ensure that this specimen clamp makes good contact with the connectors of the testing machine. The specimen clamp should remain movable to ensure that the direction of the resultant tensile load applied coincides with the axial centerline of the specimen. Once the specimen is fixed, immediately apply the load at a loading rate of 89 N/s to the standard cross-section 1.6 cm² of the tensile machine mold. Record the applied load at the instant the specimen breaks into two halves, as well as the condition of the fracture site.
• 7.6 Immediately determine the tensile strength of the remaining five wax samples according to clause 7.5. Record the average ambient temperature and relative humidity during the test.
• 7.7 Take the average of six tensile test results as the testing machine reading (N). Any test result exceeding the average by 44 N (the source text source-text extraction is “44N”, requires confirmation against the source standard (source-text extraction)) shall be discarded. Record the average of the remaining test results as the analysis result for that sample. If more than two results among the six samples have been removed, then all six test results of this group of samples shall be invalidated.

9. Qualitative and Quantitative and Calculation Formulas

• 8.1 Report the average load value calculated per square meter of cross-sectional area, accurate to 100 Pa (the source text source-text extraction is “100a0”, requires confirmation against the source standard (source-text extraction)).
• 8.2 Report whether the main shape of the fracture is neat or irregular. Report the distance from the fracture of 6 samples to the center of the sample. The distance from the fracture to the center is required not to exceed 3.2 mm (the source text source-text extraction is “3.2nvno”, requires confirmation against the source standard (source-text extraction)).
• 8.3 Report the temperature and relative humidity at the time of pouring the sample mold and at the time of the tensile strength test. If they are not 22.8℃ and 50%, the results obtained do not meet the requirements of this standard.
• Calculation formula: not provided in the available source.

10. Precision

Judge the reliability of the test results according to the following provisions (95% confidence level).

• 9.1 Repeatability: the difference between two test results obtained by the same operator under constant operating conditions, on the same testing machine, for the same sample shall not exceed the following values.
  • Range 1.05×10³～3.10×10³ kPa (the source text source-text extraction is “1.05 x 103[unreadable separator]3.10 x 103”, requires confirmation against the source standard (source-text extraction)), repeatability 1.3×10² kPa (the source text source-text extraction is “1.3 x lWkP.”, requires confirmation against the source standard (source-text extraction)).
• 9.2 Reproducibility: the difference between two results obtained by different operators in different laboratories using the same type of testing machine for the same sample shall not exceed the following values.
  • Range 1.03×10³～3.10×10³ kPa (the source text source-text extraction is “1.03 x 1[garbled exponent and separator]3.10 x 1[garbled exponent]kPa”, requires confirmation against the source standard (source-text extraction)), reproducibility 3.5×10² kPa (the source text source-text extraction is “3.5 x 1[garbled exponent]kPa”, requires confirmation against the source standard (source-text extraction)).

11. Report

• 8.1 Report the average load value calculated per square meter of cross-sectional area, accurate to 100 Pa (requires confirmation against the source standard (source-text extraction)).
• 8.2 Report whether the main shape of the fracture is neat or irregular; report the distance from the fracture of 6 samples to the center of the sample, requiring the distance from the fracture to the center not to exceed 3.2 mm (requires confirmation against the source standard (source-text extraction)).
• 8.3 Report the temperature and relative humidity at the time of pouring the sample mold and at the time of the tensile strength test. If they are not 22.8℃ and 50%, the results obtained do not meet the requirements of this standard.
• 7.6 Record the average ambient temperature and relative humidity during the test.
• 7.4.2 Record the ambient temperature and relative humidity during sample injection.

12. Referenced Documents

• GB/T 2539 Determination of Melting Point of Paraffin Wax (Cooling Curve)

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick Reference Q&A