This standard is applicable to the overall or partial stress relief of welding stress of metal equipment and the stress relief of pipeline welds in construction projects such as refineries, natural gas purification plants, long-distance pipelines, and oil and gas gathering pipelines. SY/T 4083-1995 Electrothermal Stress Relief Welding Process SpecificationSY/T4083-1995 Standard download decompression password: www.bzxz.net

Standard of the Petroleum and Natural Gas Industry of the People's Republic of China Technical rules for electric heat method of eliminating welding stressSY/T 4083--95Editor: Infrastructure Engineering Bureau of China National Petroleum CorporationApproval department: Petroleum Industry Press of China National Petroleum CorporationBeijing, 1995Technical process of eliminating welding stress by electric heat methodInspection of control and detection instrumentsSelection of temperature control equipmentSelection of control equipment:Selection of supporting components for control equipment.Operation requirements Points·
Electric heater selection and use
Electric heater power calculation:
Electric heater selection
Electric heater construction points·
Heat insulation
Temperature control
General provisions·
Temperature rise control·
Temperature drop control·
Constant temperature time
Electric heating method stress elimination quality inspection
Delivery materials
Appendix A
Appendix B
Thermal calculation
Explanation of terms used in this standard
Additional explanation
Technical specification for stress relief welding by electrothermal method
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China National Petroleum Corporation Document
(95) CNPC Technical Supervision No. 315
Notice on the approval and release of two oil and gas industry standards, including "Classification of Locations for Electrical Installations in Petroleum Facilities" To all relevant units:
Two oil and gas industry standards, including "Classification of Locations for Electrical Installations in Petroleum Facilities" (draft), have been reviewed and approved by the Municipal Government: They are now approved as oil and gas industry standards and can be released. The numbers and names of the various standards are as follows: SYT 002595
SY 7 T 408395
Classification of Locations for Electrical Installations in Petroleum Facilities (replacing SY1 25--87
Technical Specification for Electrothermal Welding Stress Relief
The above standard shall be implemented from November 15, 1995. China National Petroleum Corporation
May 1995 258
1 General Provisions
1.01 In order to reduce or eliminate the residual stress of the weld after welding, prevent cracks and stress corrosion in the weld zone, ensure the safety and reliability of the operation of the device, and obtain the best economic benefits: this standard is specially formulated.
1.0.2 This standard is applicable to the overall or partial welding stress relief treatment (hereinafter referred to as stress relief treatment) of on-site metal equipment in construction projects such as refineries, natural gas purification plants, long-distance pipelines, and oil-gathering pipelines, as well as the stress relief treatment of pipeline welds. 1.0.3 Stress relief treatment by electrothermal method shall be carried out in accordance with the working procedures. Art line reverse control. 1.0.4 Before using the electric heating method for stress relief treatment, all welding work should be completed and the welds must pass the non-destructive inspection and pass the inspection. The equipment must also pass the overall inspection and pass the stress relief treatment before it can be carried out.
1.05 For on-site welding equipment, the fan welds of the tower body and the pipeline welds, the external heat electric heating method should be used for local stress relief treatment. For the overall relief treatment of spherical storage tanks and tower bodies, the internal heat electric heating method should be used. The layout height of the internal heat electric heater is 12 degrees higher than the height of the inner space of the spherical tank. The layout height of the vertical integral stress relief electric heater of the tower body should not be higher than 23 degrees of the tower body. 1.0.6 During the stress relief test of the spherical tank, it should be carried out in accordance with GB94-86 "Construction and Acceptance Code for Spherical Storage Tanks" and GB1233790 "Steel Spherical Storage Tanks". Adjust the village legs.
1.0.7 Before the horizontal local stress relief treatment of the tower body, effective measures must be taken to ensure that the tower body meets the straightness requirements of installation after stress relief treatment. 1.0.8 Before the overall sliding stress relief treatment of spherical storage tanks and large tower bodies, there must be a construction plan or measures. And a weak heat moisturizing structure diagram should be used. 1.0.9 The stress relief treatment of the equipment should be approved by the relevant departments and the construction unit.
1.0.10 It is strictly forbidden to carry out overall stress relief treatment of spherical storage tanks and large tower bodies in strong winds and snowy weather.
1.01 For new materials, the tempering and tumbling properties of the material should be understood before stress relief treatment and the welding process should be evaluated.
1.0.12 After stress relief treatment, a hardness test should be carried out; when the hardness test fails, the pipe The equipment should be treated again immediately, and the equipment can be treated locally. The number of repeated treatments shall not exceed times. bzxZ.net
1.0.13 When using the electric heating method to treat stress, in addition to complying with this process specification, it shall also meet the design requirements.
When using the electric heating method to treat, in addition to complying with this process specification, it shall also comply with the current national standards.
Other people are strictly prohibited from working at the stress treatment site. 2.0.1
Regulations,
2 Electrothermal method to eliminate welding stress process
When using the electric heating method to treat stress, its process flow shall comply with Figure 2.0.1 2.02 According to the requirements of the process flow, after the treatment, the hardness of the treated workpiece shall be checked, and the stress measurement test shall be carried out if necessary. 2.0.3 The "Collate Handover Materials" item in the process flow (see Figure 2.01) can use a table format for the pipeline's results report, but the overall fire protection treatment results of spherical storage tanks and large towers cannot be reported in a table format. A special report sheet should be prepared in accordance with relevant regulations and designs as well as Party A's requirements. The solid sheet should have a record curve and a hardness test report. t||Our device changes the warp
controls the output
electric fresh connection
electric heater
temperature connection
automatically records the most
installed computer
programming and
heating enclosure
power supply voltage repair
201 Electric heating method to remove the brand stress process diagram to adjust the materials
3 Inspection of control and testing instruments
30.1 In addition to being calibrated and qualified according to the regulations of the measurement department, the instruments of the control equipment should also be inspected once a year, or calibrated before large-scale construction. The accuracy of the calibration instrument should be higher than that of the calibrated instrument. 3.0.2 The calibration of testing instruments including hardness testers, portable temperature detectors, etc. should be carried out in accordance with Article 3.0.1
3.0.3 Thermocouples should be tested and identified before being put into installation and operation: they can only be put into installation and operation after they pass the test
4 Selection of temperature control equipment
4.1 Selection of control equipment
4.1.1 For automatic control of fire treatment, it is advisable to use control equipment with thyristor output in programmable input mode.
4.1.2 The total capacity of the selected control equipment should be greater than or equal to the calculated total electric heating power.
4.1.3 Automatic control of fire treatment should use a large-capacity device for control. If it cannot meet the power requirements, manual compensation can be used: but the compensated power shall not be greater than 30% of the total power.
4.1.4 When programmable control equipment cannot be used under certain conditions: electric unit combination automation instrument can be used for control. ||t t||4.2 Selection of supporting components for control equipment
4.2.1 The graduation of the thermocouple should be consistent with that of the secondary instrument. 4.2.2 Thermocouples should be armored thermocouples with a diameter of less than 41mm: When using programmable control equipment, armored thermocouples should be selected. 4.2.3 The material of the temperature compensation wire should match the material of the thermocouple: When using programmable control equipment, shielded compensation wires should be used for compensation wires. 4.2.4 The number of points of the temperature recorder should meet the number of wet points of the workpiece. 4.3 Key points of operation
The computer program of the control equipment should be programmed according to the treatment process curve. 4.3.2
After the program is compiled, the output current and voltage values ​​of each channel should be adjusted to make it consistent with the current and voltage of the electric heater.
4.3.3 Before using the recording instrument, the zero-degree baseline should be adjusted. 4.3.4 When the spherical tank and tower body are subjected to overall heat treatment, the temperature measuring points should be evenly arranged -6
on the shell surface + the distance between adjacent measuring points should be within 45°: when the rear part of the tower skin pipeline is subjected to heat treatment, the temperature measuring points are arranged at the bottom of the tower or pipeline welding braid and two points and are 120° apart.
45 The thermocouple shall not be fixed on the workpiece by the tying method, but shall be fixed by welding instrument fusion welding or special thermocouple steel card: spot welding shall be used when fixing the steel card. After the heat treatment is completed, the lower steel card ear shall not damage the parent material. 4.3.6 The wiring spacing of the thermocouple terminal shall be greater than 5mm, and the cold end of the thermocouple and the compensation wire shall be excited by the heat source.
4.3.7 The wiring of the compensation wire shall be in good contact to prevent contact resistance. 4.3.8 When laying the compensation conductor, the net distance from the power line should be greater than 100mm. 5.1.1
5 Selection and use of electric heaters
5.1 Calculation of electric heater power
The dynamic elasticity of the electric heater shall comply with Appendix A. The electric power of the local stress treatment of the equipment can be estimated according to the standard evaluation of 5-7 square meters before heating. 5.2 Selection of electric heaters
5.2.1 The overall stress treatment of spherical storage tanks and large towers should use the internal heating method, and the dismantling heating method should be used:
5.2.2 The on-site fan-out treatment of pipelines and towers should use the external heating method, and crawler-type high-aluminum porcelain electric heaters should be used
Local stress treatment at the elbows and flanges of pipelines: rope-shaped electric heating towers should be used for local welding point treatment, and magnetic plate-shaped electric heaters should be used. The length of the pipeline with a belt-type electric heater is calculated according to the formula (5.2.5) L = D yuan + 20
Type: Length of the belt-type electric heater (;
D--pipeline diameter (mm);
5.2.6 Heating width: The heating width of the pipeline and tower body should be based on the center of the weld: each side should not be less than three times the width of the weld. 5.3 Key points for the construction of electric heaters
When the heater is installed on the same side of the thermocouple, the center of the heater should be aligned with the weld. 5.3.3 Steel belts or No. 8 iron wires should be used to fix the pipeline heater, and the bundling should be tight and firm to prevent loosening after heating.
5.3.4 For the circumferential weld of the tower body, multiple groups of heaters should be selected to meet its circumference, but the distance between the two groups should not be greater than the wall thickness. Five times. 5.3.5 The rigidity of the steel structure support of the internal heating method fixed frame type heating element shall meet the requirement of no deformation after heating.
The connection of the internal heating method electric heater shall meet the following requirements: 5.3.6.1
The branch line connecting the electric heater should be made of round steel, and its diameter shall not be less than the main line of each group of electric heaters. When round steel is used, its diameter shall not be less than the main line. The branch line shall be insulated with high aluminum porcelain sleeve. When the round steel is connected, the welding must be firm, and the main
lap length shall not be less than times the diameter. 5.3.6.4
When the output power supply is connected to the main line of the heater, the main line head shall be tinned. When the power cord and the main line are connected. Use staples to clamp, and the number of staples per joint shall not be less than three.
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