This standard specifies the method for determining the diffusible hydrogen content in the deposited metal by glycerol replacement method, gas chromatography and mercury replacement method. When the diffusible hydrogen content in the deposited metal determined by the glycerol replacement method is less than 2mL/100g, gas chromatography must be used for determination. The glycerol replacement method and gas chromatography in this standard are applicable to manual arc welding, submerged arc welding and gas shielded welding. The mercury replacement method is only used for manual arc welding. GB/T 3965-1995 Determination of diffusible hydrogen in deposited metal GB/T3965-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods for determination of diffusible hydrogen in deposited metal
Methods for determination of diffusible hydrogen in deposited metalSubject content and scope of application
GB/T3965---1995
Replaces GB3965--83
This standard specifies the methods for determining the diffusible hydrogen content in deposited metal by glycerol replacement method, gas chromatography and mercury replacement method. When the diffusible hydrogen content in the deposited metal determined by the glycerol replacement method is less than 2mL/100g, the gas chromatograph must be used for determination. The glycerol replacement method and gas chromatography in this standard are applicable to manual arc welding, submerged arc welding and gas shielded welding. The mercury replacement method is only applicable to manual arc welding.
2 Sample preparation
2.1 Test plate preparation
2.1.1 The material of the test plate, arc starter plate and lead-out plate can be carbon structural steel or low alloy steel. 2.1.2 The test plate, arc-starting plate and lead-out plate are pre-treated for dehydrogenation. The heating temperature is 400-650℃ and the temperature is kept for about 1 hour. The temperature is kept at 250±10℃ for about 6 hours.
2.1.3 The size of the test plate, arc-starting plate and lead-out plate is selected from Table 1 according to different welding methods and measurement methods. When conducting the hydrogen content test in the welding material standard, the size of the test plate No. 2, No. 4 or No. 5 should be used. 2.1.4 The entire surface of the test plate, arc-starting plate and lead-out plate should be processed to ensure smoothness and cleanliness. Table 1 Test plate and lead plate, lead plate size
Welding method
Manual arc welding
Submerged arc welding
Gas shielded welding
Manual electric welding
Submerged arc welding
Gas shielded welding
Manual arc welding
Submerged arc welding
Gas shielded welding
Manual electric arc welding
Submerged arc welding
Gas shielded welding
Manual arc welding
Test plate size
Approved by the State Administration of Technical Supervision on July 12, 1995 72
Lead plate, lead plate size
Thickness T Width W ||tt| |Determination method
Gas chromatography
Glycerol substitution method
Mercury substitution method
Order
Glycerol method, chromatography:
Arc starter plate
Mercury method:
Arc starter plate
Lead-out plate
Lead-out plate
1996-05-01 implementation
2.2 Preparation of welding materials
2.2.1 Manual arc welding
GB/T3965—1995
2.2.1.1 The diameter of the welding rod is 4mm. For welding rods with an efficiency of more than 130%, a diameter of 3.2mm should be used. 2.2.1.2 The welding rods shall be dried according to the conditions recommended by the manufacturer. During drying, the welding rods shall not touch each other and shall not be mixed with other welding rods. 2.2.1.3 The welding rod taken out of the oven should be used immediately. 2.2.2 Submerged arc welding
2.2.2.1 The diameter of the welding wire is 4mm.
2.2.2.2 The flux should be dried according to the conditions recommended by the manufacturer, and the stacking thickness should be less than 15mm. 2.2.2.3 The flux taken out of the oven should be used immediately, and the used flux should not be reused. 2.2.3 Gas shielded welding
2.2.3.1 The diameter of the welding wire is 1.6mm or 1.2mm. 2.2.3.2 The shielding gas should meet the requirements of the relevant standards. 2.3 Preparation of test specimens
Short arc and linear welds are used during welding. If the weld breaks during welding, the test piece shall be scrapped. 2.3.1 Preparation of samples for glycerol replacement method and chromatography method 2.3.1.1 Before welding, the arc-starting plate, test plate and lead-out plate are arranged in the length direction and fixed with copper clamps. Welding is carried out according to Figure 1. Each sample in the middle must be marked and weighed (accurate to 0.1g). e
Initiating arc plate
Welding method
Manual arc welding
Submerged arc welding
Gas shielded welding
Figure 1 Test piece
Lead-out plate
Weld length L on arc-starting and lead-out plates
2.3.1.2 Welding is carried out at room temperature. Each welding method is carried out according to the conditions specified in 2.4. 2.3.1.3 After welding, place the test piece in ice water for swing cooling within 2 seconds. Take it out immediately after cooling for 10 seconds. Remove the arc-starting plate and lead-out plate mechanically, remove the spatter and slag, clean and blow dry with acetone, and put the test pieces into their respective collectors according to the procedures specified in 3.1 and 3.2 according to different measurement methods.
2.3.1.4 Each group consists of four test pieces.
2.3.2 Preparation of mercury test pieces
2.3.2.1 Before welding, the arc-starting plate, test plate and lead-out plate are arranged in the length direction, fixed with copper clamps, and welded according to Figure 2. 73
GB/T3965-1995
Figure 2 Test piece combination and size
2.3.2.2 The total length of the middle test plate is 30mm, which can be divided into four specimens of 7.5mm each (see Figure 2) or two specimens of 15mm each, or one specimen of 15mm and two specimens of 7.5mm. Three optional combinations are recommended: a. Analyze No. 1 and No. 4 specimens (2×7.5mm) together, and analyze No. 2 and No. 3 specimens (2×7.5mm) together; b. Analyze No. 1 and No. 4 specimens (2×7.5mm) together, and analyze the middle specimen (15mm) separately; analyze two specimens (each 15mm) separately. c.
Each middle specimen must be marked and weighed (accurate to 0.01g). 2.4 Welding Specifications
2.4.1 Manual Arc Welding
2.4.1.1 The type of current and polarity selection shall be in accordance with the specifications, and AC and DC dual-purpose electrodes shall be used for AC welding. The welding current shall be 15A lower than the maximum current recommended by the manufacturer.
2.4.1.2 Weld at the speed of melting a 120130mm electrode into a 100mm weld. 2.4.2 Buried Arc Welding
2.4.2.1 The polarity selection shall be in accordance with the specifications, and AC and DC dual-purpose flux shall be used for AC welding. The welding current is about 600~~630A, the arc voltage is 28~30V, and the welding speed is 55~60cm/min. 2.4.2.2 The extension length of the welding wire and the accumulation height of the flux layer are both 30mm. 2.4.3 Gas Shielded Welding
2.4.3.1 Use DC reverse connection.
2.4.3.2 Welding current: $1.2mm260~290A, 1.6mm330~360A. 74
GB/T 3965—1995
Arc voltage: l.2mm27~31V, 91.6mm26~30V. Welding speed: (33±3) cm/min.
2.4.3.3 Distance between the end of the conductive nozzle and the specimen: 19±3mm. 2.4.3.4 Flow rate of shielding gas: 15~20L/min. 2.4.3.5 Clean the wire feed wheel before welding, and remove the residual gas and moisture in the welding torch and the gas guide tube by repeated ventilation. Cleaning can be omitted during continuous welding.
3 Hydrogen content determination method
3.1 Glycerol displacement method
3.1.1 Test equipment
The equipment for determining hydrogen content using the glycerol displacement method should have the following performance: 3.1.1.1 The composition of the test equipment is shown in Figure 3. 3.1.1.2 The shape and size of the collector are shown in Figure 4. The scale on the collector is divided into two parts: 0.02mL and 0.05mL. 0
Figure 3 Schematic diagram of measuring equipment
1-Constant temperature collection box; 2-sample; 3-collector; 4-thermometer; 5-mercury contact thermometer; 6-Constant temperature glycerine bath; 7: Collector support plate; 8-Constant temperature controller 9-Heating resistance wire 75
3.1.2 Measurement procedure
GB/T3965-1995
Minimum scale
Minimum scale
Unit: mm
Figure 4 Collector shape and size (approximately)
3.1.2.1 Place the sample prepared in 2 into the collector filled with glycerine. From the completion of welding the sample to the placement in the collector, it should be completed within 90s.
3.1.2.2 During the process of collecting diffusible hydrogen, the glycerine temperature must be maintained at 45±1℃. 3.1.2.3 After 72 hours, collect the bubbles adsorbed on the wall of the collector tube and the sample and read the gas volume accurately. 3.2 Gas chromatography
3.2.1 Test equipment
The equipment used to determine the hydrogen content by gas chromatography should have the following performance: 3.2.1.1 The collector must be able to remain sealed for a long time and be able to be reliably connected to the gas chromatograph. 3.2.1.2 The gas chromatograph should have the flow path shown in Figure 5, and the measurement accuracy should be 0.01mL. 76
Calibration H, inlet
Calibration H, outlet
GB/T3965—1995
Collector interface
Figure 5 Gas chromatography determination flow chart
1—pressure regulating valve; 2—pressure gauge; 3—stop cock, 4—pressure check valve; 5—H. Measuring tube; 6—detector, 7—molecular sieve; 8—flow meter; 9—dehydration tube 3.2.2 Determination procedure
3.2.2.1 Place the sample prepared according to 2 into the collector and pass Ar gas for 30s to replace the air in the collector. From the completion of welding of the sample to the placement in the collector, it should be completed within 120s.
3.2.2.2 Place the collector containing the sample in a 45℃ constant temperature box and store it for 72h to collect the diffused hydrogen gas. 3.2.2.3 After 72 hours, connect the collector to a pre-calibrated gas chromatograph to determine the amount of hydrogen. 3.3 Mercury displacement method
3.3.1 Test equipment
The equipment for determining hydrogen content using the mercury displacement method should have the following performance: 3.3.1.1 Mercury is used as the collecting medium.
3.3.1.2 The test piece can be placed in a vacuum for a short time to remove the external gas adsorbed on the surface of the sample. 3.3.1.3 The measurement accuracy at normal temperature and pressure is at least 0.05mL. 3.3.1.4 See Figure 6 for a schematic diagram of the collector.
3.3.2 Determination procedure
GB/T3965—1995
Sealing surfacewww.bzxz.net
4Inner diameter precision tube
Thick whole tube inner diameter 22, outer diameter 46
Figure 6 Schematic diagram of mercury method diffused hydrogen collector
Conical center 29
Unit: mm
3.3.2.1 Place the sample prepared in 2 in a low-temperature liquid tank (about -70℃) for storage, and break the lead plate and the lead plate in a cold state. When breaking, the sample stays outside the tank for no more than 10 seconds. 3.3.2.2 When transferring the sample from the low-temperature tank to the outer tube of the collector, first clean it in acetone for 3~~5s, blow dry it for about 20s, and immediately place it in the joint of the outer tube of the collector. Use a magnet to attract the sample and send it to the last position of the collector measurement part through the collector joint. This operation should be completed within 5s.
The total time from sample cleaning to the end of the operation should not exceed 60s. 3.3.2.3 The sample is kept at low pressure and 25±5℃ for 72h. Before measuring the final volume of hydrogen, record the accurate temperature and pressure of hydrogen. Take out the sample, clean it, blow it dry and weigh it (accurate to 0.01g). The added mass is equivalent to the mass of the molten metal. 3.3.2.4 Accurately read the gas volume (mL). 4 Calculation of hydrogen content
4.1 Expression of hydrogen content
The measurement result can be expressed as the hydrogen content per unit mass of deposited metal (mL/100g). Calculation of hydrogen content According to 4.2, calculate the measured value of each sample separately. Each group of four samples has an arithmetic mean value, which is the measured value of the group of samples.
4.2 Calculation of Diffusible Hydrogen Content (HDM) of Molten Metal 4.2.1 Glycerol Replacement Method
GB/T3965--1995
(HcL > 2mL/100g)
（1）
Wherein: HpM—
-Diffusible Hydrogen Content of Deposited Metal (Hydrogen Content when the value measured by glycerol method is converted into the value measured by gas chromatography), mL/100g; HcL—--Diffusible Hydrogen Content of Molten Metal measured by glycerol replacement method, mL/100g. pVTp
pow × 100
HGL V.
Wherein V is
The collected gas volume is converted into the volume of gas per 100g of deposited metal under standard conditions, mL; the collected gas volume, mL;
Welded metal mass (mass of sample after welding minus mass of sample before welding), g: accurate to 0.01g; 273, K;
(273+t), K;
Temperature in constant temperature collection box, °C;
-101, kPa;
Laboratory pressure, kPa.
4.2.2 Gas chromatography
Where: Hcc
Vee ×100
HpM = Hcc - V. =
Hydrogen content per unit mass of deposited metal determined by gas chromatography, mL/100g; Hydrogen content determined by gas chromatography is converted into volume under standard conditions, mL. 4.2.3 Mercury displacement method
After 72 hours, convert the measured hydrogen volume into the volume under standard conditions (0℃, 101kPa atmospheric pressure), and divide the volume by 1/100 of the mass of the deposited metal (the difference between the mass of the sample before and after welding). This is the diffusible hydrogen content, in mL/100g of deposited metal. 5 Use classification and record items
5.1 Hydrogen test in welding material standards
The hydrogen test in welding material standards shall be carried out according to 2 and 3, and the following items must be recorded: 5.1.1 Welding method.
5.1.2 Hydrogen measurement method.
5.1.3 Temperature and humidity of the welding environment.
5.1.4 Type of test plate.
5.1.5 Record the electrode model, brand, diameter, drying conditions, welding current, arc voltage, power source type and polarity during manual arc welding. 5.1.6 For submerged arc welding, record the type, brand, wire diameter, flux drying conditions, power source type and polarity of the welding wire and flux. 5.1.7 For gas shielded welding, record the type, brand, diameter, shielding gas composition and inner diameter of the wire guide nozzle. 5.2 Other hydrogen measurement tests
When conducting hydrogen measurement different from that specified in 2 and 3, in addition to recording the items in 5.1, the different parts must also be recorded. Additional notes:
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of Harbin Welding Research Institute of the Ministry of Machinery Industry. This standard was drafted by Harbin Welding Research Institute of the Ministry of Machinery Industry. The drafters of this standard are Li Chunfan and Chen Mo.2 Calculate the measured value of each sample respectively. Each group of four samples has its arithmetic mean value as the measured value of the group of samples.
4.2 Calculation of diffusible hydrogen content of molten metal (HDM) 4.2.1 Glycerol displacement method
GB/T3965--1995
(HcL > 2mL/100g)
（1）
Wherein: HpM—
-diffusible hydrogen content of deposited metal (the hydrogen content when the measured value of glycerol method is converted into the measured value of gas chromatography), mL/100g; HcL—--diffusible hydrogen content of molten metal measured by glycerol displacement method, mL/100g. pVTp
pow × 100
HGL V.
Wherein V is
The collected gas volume is converted into the volume of gas per 100g of deposited metal under standard conditions, mL; the collected gas volume, mL;
Welded metal mass (mass of sample after welding minus mass of sample before welding), g: accurate to 0.01g; 273, K;
(273+t), K;
Temperature in constant temperature collection box, °C;
-101, kPa;
Laboratory pressure, kPa.
4.2.2 Gas chromatography
Where: Hcc
Vee ×100
HpM = Hcc - V. =
Hydrogen content per unit mass of deposited metal determined by gas chromatography, mL/100g; Hydrogen content determined by gas chromatography is converted into volume under standard conditions, mL. 4.2.3 Mercury displacement method
After 72 hours, convert the measured hydrogen volume into the volume under standard conditions (0℃, 101kPa atmospheric pressure), and divide the volume by 1/100 of the mass of the deposited metal (the difference between the mass of the sample before and after welding). This is the diffusible hydrogen content, in mL/100g of deposited metal. 5 Use classification and record items
5.1 Hydrogen test in welding material standards
The hydrogen test in welding material standards shall be carried out according to 2 and 3, and the following items must be recorded: 5.1.1 Welding method.
5.1.2 Hydrogen measurement method.
5.1.3 Temperature and humidity of the welding environment.
5.1.4 Type of test plate.
5.1.5 Record the electrode model, brand, diameter, drying conditions, welding current, arc voltage, power source type and polarity during manual arc welding. 5.1.6 For submerged arc welding, record the type, brand, wire diameter, flux drying conditions, power source type and polarity of the welding wire and flux. 5.1.7 For gas shielded welding, record the type, brand, diameter, shielding gas composition and inner diameter of the wire guide nozzle. 5.2 Other hydrogen measurement tests
When conducting hydrogen measurement different from that specified in 2 and 3, in addition to recording the items in 5.1, the different parts must also be recorded. Additional notes:
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of Harbin Welding Research Institute of the Ministry of Machinery Industry. This standard was drafted by Harbin Welding Research Institute of the Ministry of Machinery Industry. The drafters of this standard are Li Chunfan and Chen Mo.2 Calculate the measured value of each sample respectively. Each group of four samples has its arithmetic mean value as the measured value of the group of samples.
4.2 Calculation of diffusible hydrogen content of molten metal (HDM) 4.2.1 Glycerol displacement method
GB/T3965--1995
(HcL > 2mL/100g)
（1）
Wherein: HpM—
-diffusible hydrogen content of deposited metal (the hydrogen content when the measured value of glycerol method is converted into the measured value of gas chromatography), mL/100g; HcL—--diffusible hydrogen content of molten metal measured by glycerol displacement method, mL/100g. pVTp
pow × 100
HGL V.
Wherein V is
The collected gas volume is converted into the volume of gas per 100g of deposited metal under standard conditions, mL; the collected gas volume, mL;
Welded metal mass (mass of sample after welding minus mass of sample before welding), g: accurate to 0.01g; 273, K;
(273+t), K;
Temperature in constant temperature collection box, °C;
-101, kPa;
Laboratory pressure, kPa.
4.2.2 Gas chromatography
Where: Hcc
Vee ×100
HpM = Hcc - V. =
Hydrogen content per unit mass of deposited metal determined by gas chromatography, mL/100g; Hydrogen content determined by gas chromatography is converted into volume under standard conditions, mL. 4.2.3 Mercury displacement method
After 72 hours, convert the measured hydrogen volume into the volume under standard conditions (0℃, 101kPa atmospheric pressure), and divide the volume by 1/100 of the mass of the deposited metal (the difference between the mass of the sample before and after welding). This is the diffusible hydrogen content, in mL/100g of deposited metal. 5 Use classification and record items
5.1 Hydrogen test in welding material standards
The hydrogen test in welding material standards shall be carried out according to 2 and 3, and the following items must be recorded: 5.1.1 Welding method.
5.1.2 Hydrogen measurement method.
5.1.3 Temperature and humidity of the welding environment.
5.1.4 Type of test plate.
5.1.5 Record the electrode model, brand, diameter, drying conditions, welding current, arc voltage, power source type and polarity during manual arc welding. 5.1.6 For submerged arc welding, record the type, brand, wire diameter, flux drying conditions, power source type and polarity of the welding wire and flux. 5.1.7 For gas shielded welding, record the type, brand, diameter, shielding gas composition and inner diameter of the wire guide nozzle. 5.2 Other hydrogen measurement tests
When conducting hydrogen measurement different from that specified in 2 and 3, in addition to recording the items in 5.1, the different parts must also be recorded. Additional notes:
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China. This standard is under the jurisdiction of Harbin Welding Research Institute of the Ministry of Machinery Industry. This standard was drafted by Harbin Welding Research Institute of the Ministry of Machinery Industry. The drafters of this standard are Li Chunfan and Chen Mo.
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