GB/T 2902-1998 Platinum-rhodium 30-Platinum-rhodium 6 thermocouple wire
Some standard content:
GB/T2902—1998
This standard is equivalent to the B-type thermocouple indexing table in IEC584-1:1995 "Thermocouple Part 1: Indexing Table" and the B-type thermocouple tolerance in IEC584-2:1989 "Thermocouple Part 2: Tolerance". This standard is a revision of GB/T2902—1982 "Platinum 30-Platinum 6 Thermocouple Wire and Indexing Table". This standard has the following main differences from GB/T2902—1982 (hereinafter referred to as the original standard): 1 The original standard uses the IPTS-68 temperature scale, and this standard uses the ITS-90 temperature scale, so all thermoelectric potential values have been corrected.
2 The original standard contains the thermocouple indexing table. Since there is a national standard for thermocouple indexing tables, this standard no longer lists the thermocouple indexing table. However, this standard lists the thermoelectric potential values and tolerances of thermocouples at the main temperature points to facilitate the inspection of thermocouple wires. 3 The original standard only has thermocouple wires for industrial thermocouples, and this standard adds thermocouple wires for standard thermocouples. 4 The thermoelectric potential of a single pole to platinum is an important parameter of thermocouple wires. This standard provides the graduation table and graduation calculation formula of a single pole to platinum in Appendix A (Appendix to the standard).
5 This standard has made editorial and textual modifications to the original standard in accordance with the requirements of GB/T1.1-1993 and GB/T1.22--1993. From the date of implementation, this standard will replace GB/T2902-1982 at the same time. Appendix A of this standard is the appendix to the standard.
Appendix B of this standard is the appendix to the suggestion.
This standard is proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of the Technical Committee for Standardization of Instrument Functional Materials of the Ministry of Machinery Industry. This standard was drafted by Chongqing Instrument Material Research Institute and Kunming Precious Metals Research Institute of the Ministry of Machinery Industry, and Shanghai Alloy Co., Ltd., Sichuan Instrument Factory No. 1, Northwest Copper Processing Plant, Shenyang Alloy Co., Ltd. and other units participated in the drafting. The main drafters of this standard are: Zhang Zelin, Zou Jinbao, Chen Lixin, Xue Zhenghui, Zhou Jiesheng, Pu Min, Zhang Xiaohua. This standard is entrusted to the Technical Committee for Standardization of Instrument Functional Materials of the Ministry of Machinery Industry for interpretation. This standard was first issued in February 1982.
1 Scope
National Standard of the People's Republic of China
Platinum-30-Platinum-6 Thermocouple Wires
Platinum-30%Rhodium/
Platinum-6%Rhodium thermocouple wiresGB/T2902—1998
Replaces GB/T2902—1982
This standard specifies the specifications, technical requirements, test methods, inspection rules, supply methods, packaging and marking of Platinum-30-Platinum-6 thermocouple wires.
This standard is applicable to the manufacture of industrial Platinum-30-Platinum-6 thermocouples (Type B thermocouples) and standard Platinum-30-Platinum-6 thermocouples (hereinafter referred to as thermocouple wires).
2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T16839.1—1997 Thermocouple Part 1: Dividing table GB/T16839.21997 Thermocouple Part 2: Filling difference GB/T16701.1—1996 Thermocouple material test method Part 1: Thermoelectromotive force measurement method of precious metal thermocouple wire JB/T6819.2-1993 Instrument material terminology temperature measurement material 3 Definitions
The terms defined in JB/T6819.2 apply to this standard. 4 Product classification
4.1 Product name, code and nominal chemical composition are shown in Table 1. Table 1
Product Name
Platinum Germanium 30 Alloy Wire
Platinum 6 Alloy Wire
4.2 Even Wire Grade
Nominal Chemical Composition, %
Even wire is divided into standard grade, grade I and sub-grade according to different use requirements and thermoelectric properties. The classification conditions are specified by technical requirements. 4.3 The recommended upper limit of the use temperature of even wire is shown in Table 2. Table 2
Diameter of even wire, mm
Approved by the State Administration of Quality and Technical Supervision on December 11, 1998, upper limit of long-term use temperature, ℃
Upper limit of short-term use temperature, ℃
Implementation on July 1, 1999
4.4 Marking example
Product marking shall be expressed in the following format:
GB/T2902—1998
BP-I-GB/T2902—1998
4.5 For relevant physical parameters of the product, see Appendix B (suggestive appendix). 5 Technical requirements
5.1 Surface quality
Year of standard
Standard number
Tolerance level (standard, I, II)
Product code (BP, BN)
The surface of the even wire should be flat, smooth, free of oil, folds, cracks, burrs and interlayers. Small scratches and depressions and individual dark spots that do not exceed the diameter tolerance are allowed.
5.2 Size
The diameter and allowable deviation of the even wire should comply with the provisions of Table 3. The roundness of the even wire should not exceed the allowable deviation of the diameter. Table 3
5.3 Uneven thermal electromotive force
Allowable deviation
For each roll (reel) of even wire, when the reference end temperature is 0℃ and the measuring end temperature is 1200℃, the measured uneven thermal electromotive force shall not exceed the provisions of Table 4.
Product Name
Platinum 30 Alloy Wire
Platinum 6 Alloy Wire
5.4 Thermoelectric Force
Standard Grade
Uneven Thermoelectric Force, uv
5.4.1 For industrial thermocouples composed of thermocouple wires, when the reference end temperature is 0°C, the relationship between the measuring end temperature and the thermoelectric force shall comply with the provisions of the B-type thermocouple graduation table in GB/T16839.1 and the B-type thermocouple tolerance in GB/T16839.2. The thermoelectric force and tolerance of thermocouples at the main temperature points are shown in Table 5, and the thermoelectric force rate and the graduation table of monopole to platinum are shown in Appendix A (Appendix to the Standard). 5.4.2 For a standard thermocouple consisting of a wire, when the reference end temperature is 0°C and the measuring end temperature is 1100°C and 1500°C, the corresponding thermoelectric potential and tolerance are: 5780μV±25μV and 10099μV±40μV respectively. 2
Measuring end temperature
5.5 Stability
Thermoelectric potential
Nominal value
GB/T2902—1998
Thermoelectric potential range
1783~1801
2419~2443
3139~3169
3938~3976
4811~4857
5409~5459
5604~5656
5753~5807
6755~6817
7813~7883
891 7~8995
10056~10142
10690~10780
11216~11310
12383~12483||tt ||Thermal electromotive force range
1768~1816
2404~2458
3123~3185
3919~3995
4788 4880
5383~5485
5578~5682
5726~5834
6724~6848
7777~791 9
8877~9035
10012~10186
10644~10826
11169~11357
12334~12532
5.5.1 For industrial thermocouples made of wire, when used in air at 1500℃ for 200h, the change in thermoelectric potential before and after use at 1500℃ should not exceed 46μV (about 4℃).
5.5.2 For standard thermocouples made of wire, the stability is determined by the change in thermoelectric potential before and after annealing at 1500℃. For second-class standard thermocouples, the values should not exceed 6μV and 8μV respectively. 6 Test method
6.1 Surface quality
Surface quality is observed visually.
6.2 Dimension measurement
Use a micrometer with an accuracy of not less than 0.001mm to measure in two mutually perpendicular directions on the same cross section of the even wire. At least three different parts of each roll (disk) of even wire should be measured. 6.3 Uneven Thermoelectric Potential Test
After cleaning and annealing the sample taken from the head and tail of the same coil (disk) of thermocouple, tie one end of the sample and the measuring end of the standard thermocouple with a clean platinum wire of 0.2-0.3mm diameter and put them into the thermocouple calibration furnace. When the measuring end temperature is 1200℃±10℃ and the reference end temperature is 0℃, measure its thermoelectric potential with the same pole method. The maximum difference of the thermoelectric potential of the same coil (disk) of thermocouple is the value of uneven thermoelectric potential.
6.4 Thermoelectric Potential Measurement
6.4.1 Thermocouple for industrial thermocouple
The test is carried out according to the method specified in GB/T16701.1. The test temperature points are: 1100℃, 1300℃, 1500℃. 6.4.2 Thermocouple for standard thermocouple
The test is carried out according to the method specified in GB/T16701.1. After the thermocouple sample is prepared, the sample should be subjected to stability annealing at 1100℃±20℃ for 6h before bundling and thermoelectric potential measurement. The test temperature points are 1100℃ and 1500℃. 6.5 Stability test
6.5.1 After the thermoelectric potential of the industrial thermocouple wire is measured at 1500℃ according to the method specified in 6.4.1, the sample is placed in a high-temperature tubular electric furnace at 1500℃±10℃ for 200h. After being taken out, its thermoelectric potential value is measured again at 1500℃. The difference in thermoelectric potential before and after insulation at 1500℃ is 3
of the stability value of the industrial grade wire.
6.5.2 Standard thermocouple wire
GB/T2902—1998
After the thermoelectric potential of the sample is measured according to the method specified in 6.4.2, it is placed in the annealing furnace again and annealed at 1100℃±20℃ for 6h. Then the thermoelectric potential at 1500℃ is measured again. The difference in thermoelectric potential at 1500℃ before and after annealing is the stability value of the standard grade thermocouple wire. 7 Inspection rules
7.1 Inspection classification
Product inspection is divided into factory inspection and type inspection. 7.1.1 Factory inspection
The thermocouple wire shall be inspected by the quality inspection department of the manufacturer and shall be accompanied by a product quality certificate before it can be shipped. Factory inspection items:
a) Surface quality;
b) Dimensions,
c) Uneven thermoelectric potential;
d) Thermoelectric potential:
e) Stability (Industrial thermocouple wire is not subject to this inspection) 7.1.2 Type inspection
All test items specified in this standard shall be carried out. Type inspection shall generally be carried out in any of the following circumstances: a) Trial determination and identification of new products or old products for transfer to factory production b) After normal production, if there are major changes in raw materials and processes, c) During normal production, inspection shall be carried out at least once a year, d) When the product is resumed after long-term suspension of production, e) When there is a major difference between the factory inspection results and the last type inspection, f) When the national quality supervision agency proposes a requirement for type inspection. 7.2 Sampling rules
7.2.1 For factory inspection, approximately 1.1m samples shall be taken from the head and tail ends of each roll (reel) of even wire produced for inspection, and the surface quality and size shall be inspected for the entire roll (reel) of even wire.
7.2.2 For type inspection, at least 3 rolls (reels) of even wire with positive and negative poles shall be randomly selected from qualified products, of which 1.1m shall be taken from the head and tail ends of 1 roll (reel), and 5.5m shall be taken from the other end for uneven thermal electromotive force test, and approximately 1.1m samples shall be taken from the head and tail of each other roll (reel) of even wire for inspection. However, the surface quality and size shall be inspected for the entire roll (reel) of even wire. 7.3 Judgment rules
7.3.1 During factory inspection, if any one item fails, the roll (reel) product shall be judged as an unqualified product. 7.3.2 During type inspection, if any one item fails, double sampling shall be carried out for full re-inspection. If there is still one item that fails, the type inspection is judged to be unqualified.
8 Supply method, packaging and marking
8.1 Supply method
Even wire is supplied in a work-hardened state. Each roll (reel) of even wire should be wound with one wire, without joints in the middle, and its weight should not be less than 100g. If the user needs it, even wire less than 100g is allowed to be supplied. 8.2 Packaging
Even wire should be wound into rolls or on reels, with a diameter of about 100mm. Each roll of even wire should be tied at least twice, and the wire head on the reel should be firmly fixed and packed with moisture-proof material. 8.3 Marking
8.3.1 Each roll (reel) of even wire shall be marked with: a) manufacturer's name or trademark;
b) product name and mark,
c) product number
d) gross weight and net weight of each roll (reel) of even wire; e) year, month and day of production.
GB/T2902—1998
8.3.2 The product certificate of each roll (reel) of even wire shall be marked with: a) manufacturer's name or trademark,
b) product name;
c) product number;
d) this product complies with GB/T2902—1998; e) gross weight and net weight of each roll (reel);
f) year, month and day of production.
GB/T2902—1998
Appendix A
(Appendix to the standard)
Thermoelectric potential rate of Pt30-Pt6 thermocouple wire and monopole-to-Pt graduation table Thermoelectric potential rate of Pt30-Pt6 thermocouple at main temperature points (Seebeck coefficient 8) is shown in Table A1. A1
The graduation table of Pt30 (BP)-Pt (Pt-67) is shown in Table A2. Table A2
22 006
Graduation table of Pt30 (BP)-Pt (Pt-67)
Thermoelectric potential uv
20 799
The graduation table of Pt30 (BP)-Pt (Pt-67) is calculated by the following polynomial: E
(reference end temperature is 0℃)
14 024
Where the coefficient is
Temperature range
0℃~630.615℃
Cl=4.8227875687
C2=1.5651165709X10-2
cs=-2.2233797882×10-5
Ch-2.8333244074X10-8
cs=-2.0258940447×10-11
Ce-6.1488705096X10-15
GB/T2902—1998
The graduation table of platinum (Pt-67)-platinum 6 (BN) is shown in Table A3. Table A3
630.615℃~1768.1℃
Co=—7.9680432282X10
ci-6.3941110213X10
C2=—1. 7102421410×10-1
Cs-3.0555782527X10-4
Cq——3.2105744492×10-7
Cs=2.0909102 794X10-10
C=—8.2335825426×10-14
C=1.7822841515X10-17
cs=—1.6187074187X10-21
Platinum (Pt-67)-Platinum 6 (BN) Graduation Table
Thermoelectric potential v
Platinum (Pt-67)-Platinum 6 (BN) Graduation Table is calculated by the following polynomial: E
14 047
(reference end temperature is 0℃)
wherein the coefficient is
temperature range 0℃~630.615℃
Cl-5.0692957522
C2-9.7471235920×10-8
Ca=-2.0908004718×10-5
ch-2.6766414883X10-8
cs=-1.8564487523X10-1
Ce=5.5189670386×10-15
GB/T290 2—1998
Appendix BbzxZ.net
(Suggested Appendix)
630.615℃~1768.1℃
Co——4.0742263662X103
Cl=3.5369362743×10
C2=—8.6139109315×10-2
Ca-1.4770502362X10-4
cq-—1.5270399629X10-7
Cs=9.7993087805X10-11
Cg=—3.7820394393×10-14
C7-7.9252774328X10-18
Cg-—6.8079411578×10-22
Physical parameters of Pt30 alloy wire and Pt6 alloy wire, wire density, melting point, mass per meter, resistivity, temperature coefficient of resistance, tensile strength and elongation are shown in Table B1. Table B1
Density/cm
Melting point, ℃
Mass of wire per meter, g
Resistivity at 20℃, μQ·cm
Temperature coefficient of resistance (0℃~100℃), ×10-/℃Tensile strength, MPa
Elongation, %
Platinum 30 alloy wire
Platinum 6 alloy wire
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