A heat treatment method of large-diameter X52QH hydrogen conveying pipeline pipe

Abstract

The application discloses a heat treatment method of large-diameter X52QH hydrogen transmission pipeline pipe, and the technological process is as follows: hot-rolled seamless steel pipe, heating in a quenching furnace, heat preservation in the quenching furnace, discharging, water quenching, heating in a tempering furnace, heat soaking in the tempering furnace, heat preservation in the tempering furnace, discharging, air cooling, sampling at head and tail ends, and detection and analysis. The hot-rolled X52QH hydrogen transmission pipeline seamless steel pipe adopts C+Mn+Cr+Mo+Ti alloying element combination, so that the carbon equivalent CE PCM of the steel is ≤0.19, and the seamless steel pipe is subjected to water quenching and tempering heat treatment, so that the mechanical properties of the steel pipe reach the following indexes: yield strength: 420MPa-450MPa; tensile strength: 525MPa-560MPa; yield strength ratio: ≤0.85; elongation: ≥35%; transverse impact value at 0℃: AKV≥350J / cm 2 ; grain size: ≥9 grades.

Description

Technical Field

[0001] This invention relates to the fields of ferrous metal smelting and metal pressure processing, and particularly to a heat treatment method for a large-diameter X52QH hydrogen pipeline. Background Technology

[0002] Hydrogen is considered one of the most important energy sources for widespread use in the 21st century, boasting advantages such as abundant reserves, high heat output from combustion, diverse manufacturing methods, high economic efficiency, and environmentally friendly combustion products. Currently, with finite fossil fuel resources gradually dwindling, the advantages of hydrogen energy are becoming increasingly prominent. Considering all factors, hydrogen energy possesses enormous application potential and can provide crucial support for the sustainable development of human society. However, current hydrogen transportation pipelines utilize low-strength pipeline steel to prevent hydrogen embrittlement.

[0003] Hydrogen energy, as an energy carrier, can effectively mitigate the greenhouse effect and ensure energy supply. Currently, there are approximately 3000 km of hydrogen pipelines worldwide, with a maximum service pressure of 10 MPa, mainly supplying hydrogen to the chemical or petroleum industries. The steel grade of these pipelines typically does not exceed X52. This invention aims to provide a heat treatment method for large-diameter X52QH hydrogen pipeline pipes. Summary of the Invention

[0004] The purpose of this invention is to provide a heat treatment method for large-diameter X52QH hydrogen pipeline pipes, which makes the steel pipes have excellent properties.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This invention discloses a heat treatment method for a large-diameter X52QH hydrogen pipeline, comprising:

[0007] 1) Hot-rolled X52QH seamless steel pipes for pipelines with qualified dimensional accuracy and appearance quality ensure that the carbon equivalent CE in the steel is within acceptable limits. PCM ≤0.19;

[0008] 2) The seamless steel pipe is placed into the quenching furnace and heated. The temperature of the heat preservation section of the seamless steel pipe is heated to 910±10℃ and held for 8 minutes before being taken out of the furnace.

[0009] 3) Seamless steel pipes undergo water quenching heat treatment after exiting the quenching furnace. The water spray volume from the nozzle inside the pipe end is 3600m³. 3 / h, the external water spraying capacity of the external spray pipe is 4000m³ / h. 3 / h, the external water spray starts 3 seconds after the internal water spray starts, and both the external and internal sprays last for 40-44 seconds. The radial wheel speed is 32-38 revolutions / minute, cooling the seamless steel pipe to below 100℃.

[0010] 4) Heat the seamless steel pipe to 640℃ for homogenization and heat preservation. The total time from heating to heat preservation should be controlled within 140-160 minutes, and the furnace temperature should be controlled within ±10℃.

[0011] 5) After the seamless steel pipe has undergone tempering heat treatment, it is air-cooled after being taken out of the furnace;

[0012] 6) Take 300mm samples from both ends of the heat-treated seamless steel pipe for mechanical property and microstructure analysis; if the chemical composition and mechanical properties are qualified, it is a finished product of X52QH seamless steel pipe for pipeline.

[0013] Furthermore, the chemical composition of the X52QH hydrogen pipeline by mass percentage is as follows: C 0.08-0.11%, Si 0.30-0.40%, Mn 1.0-1.15%, P ≤0.010%; S ≤0.003%, Cr 0.15-0.28%, Mo 0.1-0.15%, Ti 0.01-0.02%, with the remainder being Fe and unavoidable impurities.

[0014] Furthermore, the performance of the X52QH hydrogen pipeline is as follows: yield strength: 420MPa~450MPa; tensile strength: 525MPa~560MPa; yield ratio: ≤0.85; elongation: ≥35%; transverse impact value at 0℃: AKV≥350J / cm 2 Grain size: ≥9.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0016] The hot-rolled X52QH seamless steel pipe for hydrogen pipelines uses a combination of C+Mn+Cr+Mo+Ti alloying elements to produce seamless steel pipes with a wall thickness of 11mm for hydrogen pipelines, resulting in a high carbon equivalent (CE) content in the steel. PCM ≤0.19.

[0017] This steel pipe undergoes water quenching and tempering heat treatment, resulting in excellent performance across the board. Specific performance indicators are as follows: Yield strength: 420MPa~450MPa; Tensile strength: 525MPa~560MPa; Yield-to-tensile ratio: ≤0.85; Elongation: ≥35%; Transverse impact value at 0℃: AKV≥350J / cm 2 Grain size: ≥9. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] Figure 1 This is a microscopic tissue photograph of Example 1;

[0020] Figure 2 This is a microscopic tissue photograph of Example 2;

[0021] Figure 3 This is a microscopic tissue photograph of Example 3. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to Examples 1 to 3.

[0023] The hot-rolled X52QH seamless steel pipe for hydrogen pipelines is rolled to a qualified state, so that the carbon equivalent CEPCM in the steel is ≤0.19.

[0024] The production process sequence is as follows: hot-rolled seamless steel pipe → quenching furnace heating → quenching furnace heat preservation → unloading → water quenching → tempering furnace heating → tempering furnace homogenization → tempering furnace heat preservation → unloading → air cooling → sampling at the head and tail ends → testing and analysis.

[0025] The specific production process is briefly described below:

[0026] 1. The hot-rolled X52QH seamless steel pipe for hydrogen pipelines is rolled to a qualified state, so that the carbon equivalent CE in the steel is high. PCM ≤0.19.

[0027] 2. The seamless steel pipe is loaded into the quenching furnace. After passing through the heating section and the heat preservation section, the temperature of the seamless steel pipe in the heat preservation section is heated to 910℃ and held for 8 minutes.

[0028] 3. Seamless steel pipes undergo water quenching heat treatment after exiting the quenching furnace. The water spray volume from the nozzle inside the pipe end is 3600 ml. 3 / h, the external water spraying capacity of the external spray pipe is 4000m³ / h. 3 / h, the external water spray starts 3 seconds after the internal water spray starts, and both the external and internal spray last for 42 seconds. The radial wheel speed is 35 revolutions per minute, which cools the seamless steel pipe to below 100℃;

[0029] 4. Heat the seamless steel pipe to 640℃ for homogenization and heat preservation. The total time from heating to heat preservation should be controlled within 150 minutes, and the furnace temperature should be controlled within ±10℃.

[0030] 5. After the seamless steel pipe has undergone tempering heat treatment, it is air-cooled after being taken out of the furnace.

[0031] 6. Take 300mm samples from both ends of the heat-treated seamless steel pipe for mechanical property and microstructure analysis.

[0032] After heat treatment, seamless steel pipes with specifications of Ф457mm×11mm×12000mm (outer diameter of steel pipe × wall thickness of steel pipe × length of steel pipe) X52QH for hydrogen pipelines were sampled and subjected to chemical analysis. The chemical composition analysis results (weight percentage content) are shown in Table 1, the mechanical property test results are shown in Table 2, the metallographic property test results are shown in Table 3, and the microstructure photographs are shown in Table 4. Figures 1-3 As shown.

[0033] Table 1. Chemical composition analysis results of the tube blank (wt%)

[0034] Example 1 0.09 0.31 1.10 0.005 0.002 0.19 0.12 0.011 0.18 Example 2 0.10 0.31 1.09 0.008 0.003 0.24 0.13 0.012 0.18 Example 3 0.09 0.32 1.01 0.007 0.002 0.21 0.11 0.014 0.18

[0035] Table 2. Mechanical property test results of seamless steel pipes

[0036] Example 1 431 535 0.80 43 421，403，410 Example 2 441 530 0.83 41 391，403，402 Example 3 449 544 0.82 42 415，399，409

[0037] Table 3. Metallographic Performance Test Results of Seamless Steel Pipes (Grade)

[0038]

[0039] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A heat treatment method for a large-diameter X52QH hydrogen pipeline, characterized in that, include: 1) Hot-rolled X52QH seamless steel pipes for pipelines with qualified dimensional accuracy and appearance quality ensure that the carbon equivalent CE in the steel is within acceptable limits. PCM ≤0.19; 2) The seamless steel pipe is placed into the quenching furnace and heated. The temperature of the heat preservation section of the seamless steel pipe is heated to 910±10℃ and held for 8 minutes before being taken out of the furnace. 3) Seamless steel pipes undergo water quenching heat treatment after exiting the quenching furnace. The water spray volume of the nozzle inside the pipe end is 3600m³. 3 / h, the external water spraying capacity of the external spray pipe is 4000m³ / h. 3 / h, the external water spray starts 3 seconds after the internal water spray starts, and both the external and internal sprays last for 40-44 seconds. The radial wheel speed is 32-38 revolutions / minute, cooling the seamless steel pipe to below 100℃. 4) Heat the seamless steel pipe to 640℃ for homogenization and heat preservation. The total time from heating to heat preservation should be controlled within 140-160 minutes, and the furnace temperature should be controlled within ±10℃. 5) After the seamless steel pipe has undergone tempering heat treatment, it is air-cooled after being taken out of the furnace; 6) Take 300mm samples from both ends of the heat-treated seamless steel pipe for mechanical property and microstructure analysis; if the chemical composition and mechanical properties are qualified, it is a finished product of X52QH seamless steel pipe for pipeline. The chemical composition of the X52QH hydrogen pipeline by mass percentage is as follows: C 0.08-0.11%, Si 0.30-0.40%, Mn 1.0-1.15%, P≤0.010%; S≤0.003%, Cr 0.15-0.28%, Mo 0.1-0.15%, Ti 0.01-0.02%, with the remainder being Fe and unavoidable impurities. The performance of the X52QH hydrogen pipeline is as follows: yield strength: 420MPa~450MPa; tensile strength: 525MPa~560MPa; yield ratio: ≤0.85; elongation: ≥35%; transverse impact value at 0℃: AKV≥350J / cm 2 ; Grain size: ≥9.

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