Method for mounting and dismounting a product welding test piece during heat treatment of a spherical tank
By welding steel claws to the outside of the spherical tank wall and fixing the welded specimen with refractory materials and high-temperature sand, the problem of inconsistent heat treatment between the welded specimen and the spherical tank was solved, and synchronous heating and cooling and accurate performance evaluation were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROCHEMICAL CORP
- Filing Date
- 2023-12-20
- Publication Date
- 2026-06-30
AI Technical Summary
In the existing technology, it is difficult to keep the welded test piece of the product in close contact with the outside of the spherical tank during heat treatment, resulting in inconsistent heating and cooling rates, which affects the heat treatment effect. Furthermore, the performance is inconsistent when the design and owner's contract requirements are stringent, leading to inaccurate test conclusions.
The method involves welding steel claws to the outside of the spherical tank wall and hammering in flat wedges. The welded specimens are then fixed with refractory materials and high-temperature sand. They are then heat-treated together with the spherical tank, and the fixing device is removed after the heat treatment.
This enabled simultaneous heat treatment of the welded specimens and the spherical tank, ensuring consistent performance, meeting stringent design and owner contract requirements, and providing accurate performance evaluation.
Smart Images
Figure CN117867250B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of spherical tank heat treatment technology, specifically relating to a method for installing and disassembling a product welding specimen during spherical tank heat treatment. Background Technology
[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] With the continuous development of petrochemical construction, the number of storage tanks and spherical containers / tanks is also gradually increasing. Post-weld heat treatment of spherical tanks can eliminate residual welding stress, stabilize structural dimensions, and homogenize intergranular structure, thereby extending product service life and ensuring safe operation.
[0004] To verify the quality of the spherical tank after construction, it is necessary to verify various mechanical properties of the weld seams. GB12377-2014 stipulates that during the welding of the spherical tank, a product test plate of the same standard, grade, thickness, location, and bevel type as the material used in the tank must be used. This test plate must be obtained under the same conditions, environmental circumstances, and welding process, and after welding by a qualified welder. The test plate must undergo the same heat treatment process as the tank. During heat treatment, the test plate should be placed outside the high-temperature zone of the spherical shell, in close contact with the shell, and heat-treated together with the tank. Afterwards, test specimens are prepared using the test plate. Only when all standards are met can the next step be carried out.
[0005] There are no strict rules regarding how to fix the product welding test plate. Since the product welding test plate is a flat surface and the spherical tank is spherical, the contact between them is point contact. Improper fixing will affect the heat treatment effect of the product welding test piece. For example, the heating and cooling rates may not be synchronized with the overall spherical tank, and the temperature difference between the product welding test piece and other parts of the spherical tank during the isothermal period may be significant, leading to exceeding the minimum temperature range for heat treatment. Sometimes, the installation location required by the design and owner's contract is extremely stringent, causing a deviation between the performance of the product welding test piece and the performance of the spherical tank. This will result in inconsistent performance between the product welding test piece and the spherical tank, making the final test conclusions of all samples inaccurate. Summary of the Invention
[0006] To address the shortcomings of existing technologies, the present invention aims to provide a method for installing and disassembling product welding test pieces during heat treatment in a spherical tank, ensuring that the welding test plate remains in close contact with the outside of the spherical tank throughout the entire heat treatment process, and that the heating, cooling, and heat preservation of the welding test plate are synchronized with those of the spherical tank.
[0007] To achieve the above objectives, the technical solution of the present invention is as follows:
[0008] A method for installing and disassembling a product welding test piece during heat treatment in a spherical tank, comprising the following steps:
[0009] S1. Prepare the product welding test pieces for the spherical tank and mark the placement positions of the test pieces on the outside of the spherical tank wall.
[0010] S2. Weld steel claws at the marked positions and place the product welding test piece in.
[0011] S3. Drive a flat wedge between the steel claw and the product welding test piece, and fill the gaps in the other three directions on the outer periphery of the test piece with refractory material.
[0012] S4. Pour high-temperature sand into the gap above the specimen and compact it.
[0013] S5. Install the insulation steel belt along with the spherical tank, arrange the refractory material, and perform heat treatment.
[0014] S6. After heat treatment is completed, remove the insulation material, disassemble the test plate, and grind off the steel claws on the spherical tank.
[0015] Furthermore, the refractory material is a flexible refractory material.
[0016] The beneficial effects of this invention are as follows:
[0017] 1. This method utilizes locally sourced materials and self-processing, employing minimal costs and the simplest methods and equipment to ensure that the heat treatment effect of the specimen is consistent with the overall heat treatment of the spherical tank. This effectively guarantees that the performance of the welded specimen of the spherical tank can accurately reflect the performance of the spherical tank, thereby enabling accurate evaluation of the spherical tank's performance using the welded specimen.
[0018] 2. The fixing effect of the present invention is extremely strong, and it can be fixed in a vertical position on the outside of the equatorial zone. It will not fall off due to high temperature deformation or other factors during heat treatment, and can meet more stringent design and owner contract requirements. Attached Figure Description
[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0020] Figure 1 This is a schematic diagram of the fixing method of the product welding test plate in Example 1;
[0021] Figure 2 for Figure 1 AA view;
[0022] Figure 3This is a schematic diagram of the flat wedge shape used in Example 1;
[0023] Figure 4 This is the temperature change curve in Example 2.
[0024] Among them: 1. Product welding test piece, 2. Spherical tank wall, 3. Steel claw, 4. Steel claw fixing weld, 5. Flat wedge, 6. Refractory material, 7. High temperature sand, 8. Test piece weld, 9. Semi-grooved nut. Detailed Implementation
[0025] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0027] Example 1: A method for installing and disassembling a product welding test piece during heat treatment in a spherical tank, the specific steps of which are as follows.
[0028] S1. Prepare the product welding test piece 1 for the spherical tank, and mark the test piece placement position on the outside of the spherical tank wall 2.
[0029] The product welding test plates for the spherical tank are each 180mm×650mm in size and have the same thickness as the spherical tank wall. Two plates are used as a group. The bevel form is the same as the inner and outer bevel form of the spherical shell plate. The welding posture can be selected as flat welding (F) + overhead welding (O), horizontal welding (H) and vertical welding (V).
[0030] According to technical requirements, the product welding test plate is welded into product welding test piece 1, and steel stamp numbers are marked on welding test piece 1 according to the welder number and welding position form.
[0031] Mark the equatorial zone of the spherical tank wall 2 at 120° intervals (for 3 test plates), or mark the equatorial zone at 180° intervals (for 2 test pieces).
[0032] The equatorial zone refers to the steel plate strip around the tank at half its height, where the horizontal cross-sectional area is largest, which corresponds to the Earth's equator.
[0033] The commonly used placement location for the test plate is the high-temperature side of the outer surface of the spherical tank, i.e., the upper polar zone. However, fixing it outside the equatorial zone is more difficult than fixing it outside the upper polar zone. Furthermore, the old standard required fixing the welded specimen outside the equatorial zone of the spherical tank, so installing the test plate outside the equatorial zone still has technical significance. Moreover, if it can be successfully installed outside the equatorial zone, it can certainly be successfully installed in the upper polar zone, proving that the installation firmness can reach a high level. Therefore, in this embodiment, the outer equatorial zone is chosen as the specimen installation location.
[0034] S2. Weld steel claws 3 to the marked positions and place product welding test piece 1 inside, such as... Figure 1 , 2 As shown.
[0035] First, weld an L-shaped steel claw 3 below the marked position. The steel claw fixing weld 4 is located on the outside of the L-shaped steel claw 3. The L-shaped steel claw 3 and the spherical tank wall 2 form a groove to support the product welding test piece 1. After the product welding test piece 1 is placed stably, weld a steel claw 3 of the same shape at a symmetrical position above the marked position, but the direction of the steel claw 3 is opposite, so that the product welding test piece 1 is restricted between the L-shaped steel claw 3 and the spherical tank wall 2.
[0036] The space between the four steel claws 3 and the spherical tank wall 2 is slightly larger than the thickness of the product welding test piece 1, so that after the product welding test piece 1 is placed in it, the flat wedge 5 can still be driven in, so that the product welding test piece 1 is close to the spherical tank wall 2.
[0037] S3, a flat wedge 5 is driven into the space between the steel claw 3 and the specimen 1. The gaps on the outer periphery of the specimen, excluding the top, are then sealed with refractory material 6. Figure 1 As shown.
[0038] The four flat wedges 5 are driven in the same direction and driven in symmetrical order, for example, driven in the order of lower left, upper left, lower right, upper right, or driven in the order of lower left, lower right, upper left, upper right.
[0039] The sound of the impact is clear and crisp, like striking the tank, indicating that the product welding test piece 1 has adhered tightly to the tank wall 2.
[0040] The hardness of the flat wedge material is lower than that of the test plate.
[0041] Refractory material 6 is a flexible refractory material, preferably refractory aluminum silicate felt, and the gaps are sealed with a flat-nose screwdriver.
[0042] S4. Pour high-temperature sand 7 into the gap above the specimen and compact it with vibration. Figure 2 As shown.
[0043] When pouring high-temperature sand 7, gently tap the outer surface of the product welding test piece 1 with a small hammer to make it vibrate slightly, so that the sand particles fill the gaps from top to bottom until the sand particles fill the upper gap of the product welding test piece 1. Check the blockage in three directions again to confirm that the seal is good.
[0044] High-temperature sand 7 is fine-grained high-temperature sand, preferably corundum or quartz sand with a particle size of about 1 mm.
[0045] Ordinary yellow sand can also be sieved to remove powdery and lumpy components, leaving only gravel of suitable particle size.
[0046] If the particle size is too large, it will be difficult to effectively fill the gap between the product test plate and the spherical tank wall, affecting the heat transfer and fixation effect; if the particle size is too small, or even powdery, the thermal conductivity will be too poor, affecting the heat transfer.
[0047] S5. Install the insulation steel belt along with the spherical tank and lay the refractory material.
[0048] Preferably, the thickness of the refractory material at the test plate placement location is twice that of other locations.
[0049] Before installing the insulation steel strip, weld the semi-slotted nut 9 for fixing the temperature measurement on the side of the weld seam 8 of the product welding test piece 1, and install the thermocouple.
[0050] S6. After heat treatment is completed, remove the insulation material, disassemble the test plate, and grind off the steel claws on the spherical tank.
[0051] When the overall temperature of the spherical tank drops to room temperature, after removing the insulation material, first remove the refractory material 6 from the gaps on both sides and below the welded test piece 1 of the product, release the high-temperature sand 7 inside, and then knock the flat wedge 5 in the opposite direction. After the flat wedge 5 is loosened, remove the flat wedge 5 and use a grinding wheel to grind and remove the four steel claws 3 on the wall 2 of the spherical tank. After surface non-destructive testing, the welded parts of the steel claws 3 must not have any defects.
[0052] The purpose of tightly sealing the product welding specimen 1 with insulating material is to prevent leakage of high-temperature sand and to maintain heat. The function of high-temperature sand 7 is to conduct heat, so that the temperature of product welding specimen 1 and spherical tank wall 2 can quickly reach the same level. The high-temperature sand 7 is chemically stable and will not damage spherical tank wall 2 or product welding specimen 1 during heat treatment. It is also physically stable, with minimal thermal expansion, and will not deform during heat treatment, causing spherical tank wall 2 to separate from product welding specimen 1 or to expand the steel claws 3. If spherical tank wall 2 or product welding specimen 1 undergoes slight thermal deformation during heat treatment, the high-temperature sand 7 can flow and change shape to ensure that spherical tank wall 2 and product welding specimen 1 remain tightly adhered, ensuring the heat conduction effect. Similarly, the flexible refractory material can also deform to a certain extent according to the deformation of product welding specimen 1 and spherical tank wall 2 during heat treatment, maintaining a tight sealing effect even in high-temperature environments and preventing leakage of high-temperature sand.
[0053] Example 2: Temperature change curves of the spherical tank and welded specimen at different locations, measured using the method in Example 1.
[0054] Thermocouples were installed at multiple locations on the wall 2 of the spherical tank. Thermocouples on the welded specimen 1 were installed at the semi-grooved nut 9 position on the side of the weld seam 8. Temperature values collected at different time points during the heat treatment process are shown in Table 1. Representative positions 1 and 2 were selected, and temperature change curves were plotted against the temperature of the test plate. Figure 4 As shown.
[0055] Table 1
[0056]
[0057]
[0058] Table 2 and Figure 4 During the heating phase, the temperature of the welded specimen was slightly lower than that of the spherical tank. However, during the isothermal phase, the temperature of the welded specimen remained at the same level as that of the spherical tank.
[0059] During the cooling phase, the temperature of the welded specimen was slightly higher than that of the spherical tank, but both remained within the allowable temperature difference range specified in the design specifications and national standards, and were less than the 130℃ limit deviation for temperature rise and fall. Therefore, the welded specimen and the spherical tank underwent the same heat treatment process, and the performance of the welded specimen can reflect the performance of the spherical tank.
[0060] Based on prior thermal calculations of the spherical tank, the heat loss due to conduction during the heating process along the tank wall is negligible and does not affect the heat treatment effect; the heat loss is within acceptable limits. Applying the technical solution of this invention, as long as the welded specimen is in close contact with the spherical tank, the requirement for simultaneous heating of the specimen and the overall temperature of the spherical tank can be met.
[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for installing and disassembling a product welding test piece during heat treatment in a spherical tank, characterized in that, Including the following steps: S1. Prepare the product welding test piece for the spherical tank and mark the test piece placement position on the outside of the spherical tank wall; the outside of the equator is the test piece installation position; S2. Weld steel claws at the marked positions and place the product welding test piece inside. In S2, firstly, weld an L-shaped steel claw below the marked position. The steel claw fixing weld is located on the outside of the L-shaped steel claw. The L-shaped steel claw forms a groove with the spherical tank wall, which can support the product welding test piece. After the product welding test piece is placed securely, weld steel claws of the same shape at the symmetrical position above the marked position, but with the steel claws facing opposite directions, so that the product welding test piece is confined between the L-shaped steel claw and the spherical tank wall. S3. Drive a flat wedge between the steel claw and the product welding test piece, and fill the gaps in the other three directions on the outer periphery of the test piece with refractory material. S4. Pour high-temperature sand into the gap above the specimen and compact it with vibration; S5. Install the insulation steel belt along with the spherical tank, arrange the refractory material, and perform heat treatment; S6. After heat treatment is completed, remove the insulation material, disassemble the test plate, and grind off the steel claws on the spherical tank. In S3, the refractory material is a flexible refractory material.
2. The method for installing and disassembling the product welding test piece during heat treatment in a spherical tank as described in claim 1, characterized in that, In S1, the product welding test piece is welded from the product welding test plate. Each piece is 180mm×650mm in size and has the same thickness as the spherical tank wall. Two pieces are used as a group. The bevel form is the same as the inner and outer bevel form of the spherical shell plate. The welding postures include flat welding + overhead welding, horizontal welding and vertical welding.
3. The method for installing and disassembling the product welding test piece during heat treatment in a spherical tank as described in claim 1, characterized in that, In S3, multiple flat wedges are driven in the same direction and driven in symmetrical order until the sound of the impact is as clear as striking a can.
4. The method for installing and disassembling the product welding test piece during heat treatment in a spherical tank as described in claim 1, characterized in that, In S3, the refractory material includes refractory aluminum silicate felt, and the gaps are sealed with a flat-nose screwdriver.
5. The method for installing and disassembling the product welding test piece during heat treatment in a spherical tank as described in claim 1, characterized in that, In S4, when pouring high-temperature sand, use a small hammer to tap the outer surface of the product welding test piece to generate vibration until the sand particles fill the upper gap of the product welding test piece.
6. The method for installing and disassembling the product welding test piece during heat treatment in a spherical tank as described in claim 5, characterized in that, The high-temperature sand is fine-grained high-temperature sand.
7. The method for installing and disassembling a product welding specimen during heat treatment in a spherical tank as described in claim 6, characterized in that... The high-temperature sand is corundum or quartz sand with a particle size of 1 mm.
8. The method for installing and disassembling a product welding specimen during heat treatment in a spherical tank as described in claim 5, characterized in that, The high-temperature sand is yellow sand.
9. The method for installing and disassembling a product welding specimen during heat treatment in a spherical tank as described in claim 1, characterized in that, In S5, the thickness of the refractory material at the test plate placement location is twice that of other locations.