This standard is applicable to the measurement of secondary recrystallization temperature of doped tungsten wire with diameter of φ0.1 (or smaller) ~ 0.35 mm. GB/T 4106-1983 Measurement method of secondary recrystallization temperature of tungsten wire GB/T4106-1983 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination method for secondaryrecrystallization temperature of tungsten wire
Determination method for secondaryrecrystallization temperature of tungsten wire This standard applies to 0.1 (or less) ~ 0.35mm doped tungsten wire_Determination of secondary recrystallization temperature 1 Method principle
UDC 669.27-426
GB 4106--83
When the primary and secondary recrystallization of doped tungsten wire begins and ends, the ultimate tensile strength changes suddenly. The primary recrystallization temperature can be determined by the annealing temperature corresponding to the mutation point.
2 Sample preparation
2.1 Cleaning
Boil and wash in a 20% sodium hydroxide solution, then rinse with water to remove the milk on the surface of the tungsten wire, make the surface of the tungsten wire bright, and then dry it.
2.2 Diameter measurement
Use the weighing method to calculate the diameter of the tungsten wire according to the following formula. D
Where: D is the diameter of the tungsten wire, mm,
MG—weight of 200mm long tungsten wire, mg.
The calculated value is accurate to the second decimal place. 2.3 Sample length
Generally 250mm.
3 Test equipment
3.1 Heating device
The heating device consists of a molybdenum electrode chuck, a copper conductive rod, a metal bell jar, etc. that directly heats the sample. The chuck size should be as small as possible and match the size of the heat-treated wire to reduce heat conduction losses. 3.2 Hydrogen supply system
Includes delivery pipelines, flow meters, control switches, purification equipment and testing instruments. Hydrogen is used as a protective gas for heat-treated wires, and its dew point must be lower than -45°C. 3.3 Recording instrument
Use 0.5-level precision current and voltage meters to record current and voltage values. Use a stopwatch to control the heating and insulation time. 3.4 Power supply and regulation
Use a stabilized power supply and use a thyristor voltage regulator to regulate the voltage and increase the temperature. 3.5 Tensile testing machine
The accuracy of the tensile indication is that the error does not exceed ±1%. National Bureau of Standards 1983-12-27 Issued
1984-12-01 Implementation
Test stepsbzxZ.net
4.1 Baking furnace
GB 4106--83
Use a pigeon wire of appropriate size, hold it on the head, put down the bell cover, and pass hydrogen to remove the air. Then heat the wire to a red hot state, keep it for several minutes, and remove the bare wire in the furnace.
4.2 Thermoelectric properties measurement
The sample is clamped in the straightening shop on the fire head 1, so that the length of the heated part is 100mm. Put down the cover, pass the purified hydrogen with a flow rate of 6" min, and turn on the power after the air is removed. The stabilizer works normally, and the temperature can be gradually increased and completely melted. Note the current () and voltage () corresponding to the preparation point. According to the values ​​of and, calculate the resistance of the corresponding point. The value is accurate to the "th decimal place. Then calculate R, with the following formula, and the value is accurate to the "th decimal place. Then according to the R'-T comparison table, the corresponding heating temperature (T) is obtained, and then the 7 relationship diagram is drawn (see Figure 1). R'=Ri
一=L=1R×10° when the unit size is unit size;
R——electric limit when the temperature is T, Q
D-tungsten wire diameter, cm:
L—length of the heated part of the sample, cm.
RT comparison table
R', $2.cm
4.3 Heat treatment
GB4.106-83
Figure 1 Schematic diagram of I-T relationship
Select appropriate current for heat treatment according to the /-T relationship. Sample heating lx is 100mm, hydrogen flow rate is 6Lmin, operation: proceed in sequence according to 4.2. Heat to the required current within 30s each time and keep for 1min. Then cool down and remove the sample after cooling. There are no less than three samples at each heat treatment temperature point.
4.4 Tensile
The tensile testing machine should be used at more than 10% of the tensile measurement range, and the sample should be pulled off at a slower speed. Record the tensile force value at the break. Calculate the tensile strength Us (expressed in g/mg200 or kgf/mm2). 5 Test results
5.1 Determination of secondary recrystallization temperature
Draw the 0T curve (see Figure 2) according to the temperature corresponding to (b2) when the curve begins to drop sharply and tends to relax.
The temperature corresponding to the arithmetic mean value (05, +062):2 is determined as the secondary recrystallization temperature T.
Figure 2 T curve schematic
Test report
Test The report should include the following:
This standard number:
Tungsten wire production name;
Tungsten wire brand;
Tungsten wire batch number;
Tungsten wire size,
Secondary recrystallization temperature T1 and T2.
Additional remarks:
GB4106-
This standard was proposed by the Ministry of Metallurgical Industry of the People's Republic of China. This standard was drafted by the Central Iron and Steel Research Institute. The main drafter of this standard was Peng Kaiyuan.
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