A method for manufacturing a super low carbon l360qh seamless steel pipe for hydrogen transport

Abstract

The application discloses a manufacturing method of a super-low-carbon L360QH seamless steel pipe for hydrogen transmission, and the chemical composition of the seamless steel pipe in percentage by mass is as follows: C 0.05-0.07%, Si 0.25-0.35%, Mn 1.15-1.22%, P≤0.010%, S≤0.003%, Cr 0.18-0.28%, Mo 0.10-0.15%, V 0.02-0.04%, Ti 0.01-0.02%, and the rest is Fe and inevitable impurities; the manufacturing method comprises the following steps: heating of a pipe blank, piercing, continuous rolling, sizing, cooling, sawing, heat treatment, flaw detection, water pressure, artificial inspection and detection analysis. The steel pipe manufactured by the method has excellent performances.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ferrous metallurgy and metal pressure processing, in particular to a manufacturing method of a super-low-carbon L360QH seamless steel pipe for hydrogen transportation. BACKGROUND

[0002] Hydrogen energy has the outstanding advantages of convenient storage and transportation, diverse sources, and clean and environmental protection, and is an important part of future energy structure. Many countries have made the development of hydrogen energy an important energy strategy. Hydrogen transportation is an important link in the utilization of hydrogen energy, and safe and efficient hydrogen transportation technology is a prerequisite for large-scale commercial development of hydrogen energy. The present application relates to a super-low-carbon L360QH seamless steel pipe for hydrogen transportation, which realizes economic reliability, stable performance, perfect pipeline pipe high-end product serialization, improves product market competitiveness, and creates good economic benefits for the company. SUMMARY

[0003] The purpose of the present application is to provide a manufacturing method of a super-low-carbon L360QH seamless steel pipe for hydrogen transportation, which has excellent performance.

[0004] To solve the above technical problems, the present application adopts the following technical solutions:

[0005] The manufacturing method of the super-low-carbon L360QH seamless steel pipe for hydrogen transportation comprises the following steps:

[0006] The manufacturing method comprises the following steps:

[0007] 1. Producing a L360QH seamless steel pipe blank for hydrogen transportation with qualified chemical composition and quality, so that the carbon equivalent CEpcm in the steel is ≤0.19;

[0008] 2. The pipe blank is loaded into a ring heating furnace and heated through three stages of preheating, heating and soaking, the preheating temperature is 650-900℃, the heating temperature is 900-1180℃, and the soaking temperature is 1200-1240℃;

[0009] 3. The pipe blank is sent out of the ring heating furnace and sent into a piercing mill for piercing, the consistency of the piercing mill body and the front and rear rolling center lines is ensured, and the temperature after piercing is ≥1130℃;

[0010] 4) The perforated pipe is sent to a Ф460mm PQF hot continuous rolling mill to ensure that the temperature of the pipe before entering the rolling mill is ≥950℃;

[0011] 5) According to the different wall thickness of the pipe, the sizing mill set selects different numbers of racks to size, and the temperature of the pipe after sizing is ≥850℃;

[0012] 6) The pipe after the sizing mill set is air-cooled on a cooling bed, and after air-cooling to room temperature, it is sawn, inspected, and manually inspected;

[0013] 7) The hot-rolled seamless pipe with qualified appearance size is subjected to quenching and tempering heat treatment, the temperature of the heating furnace holding section is 920±10℃, the holding time is 5-10 minutes, the heating temperature of the tempering furnace is 680±10℃, the holding time is 5-10 minutes, and then the pipe is discharged and air-cooled;

[0014] 8) After heat treatment, the pipe is straightened, inspected, water-pressured, and sampled for related test experiments. The sample is subjected to detection and analysis of chemical composition and mechanical properties.

[0015] Further, the chemical composition of the seamless pipe in mass percentage is: C 0.061%, Si 0.27%, Mn 1.17%, P 0.011%, S 0.002%, Cr 0.20%, Mo 0.12%, V 0.03%, Ti 0.013%, and the rest is Fe and unavoidable impurities.

[0016] Further, the chemical composition of the seamless pipe in mass percentage is: C 0.057%, Si 0.28%, Mn 1.19%, P 0.013%, S 0.002%, Cr 0.21%, Mo 0.13%, V 0.03%, Ti 0.011%, and the rest is Fe and unavoidable impurities.

[0017] Further, the chemical composition of the seamless pipe in mass percentage is: C 0.063%, Si 0.29%, Mn 1.20%, P 0.010%, S 0.003%, Cr 0.21%, Mo 0.11%, V 0.03%, Ti 0.012%, and the rest is Fe and unavoidable impurities.

[0018] Further, the yield ratio of the manufactured seamless pipe satisfies ≤0.6.

[0019] Compared with the prior art, the beneficial technical effects of the present application are:

[0020] The chemical composition adopts C+Mn+Cr+Mo+V+Ti alloying system, which realizes solid solution strengthening and fine grain strengthening combination, improves the strength and impact toughness of the material, and realizes low-carbon production of the L360QH seamless steel pipe for hydrogen transmission through the ultra-low carbon alloying design and offline normalizing process, and the product performance meets the requirements of GB / T9711 standard, and the carbon equivalent CEPcm in the steel is ≤0.19.

[0021] The production through the product heat treatment process realizes excellent performance of the steel pipe, and the specific performance meets the indexes as follows:

[0022] Yield strength: 380-410 MPa; tensile strength: 500-530 MPa; yield strength ratio: ≤0.60; elongation: ≥40%; transverse impact value at 0℃: A KV ≥200 J / cm 2 Shear area ratio: ≥85%; grain size: ≥9.0 levels. BRIEF DESCRIPTION OF DRAWINGS

[0023] The application will be further described in combination with the drawings.

[0024] Figure 1 It is the microstructure photo of example 1;

[0025] Figure 2 It is the microstructure photo of example 2;

[0026] Figure 3 It is the microstructure photo of example 3. DETAILED DESCRIPTION

[0027] The application will be further described in combination with examples 1-3.

[0028] The chemical composition and quality of the L360QH seamless steel pipe blank for hydrogen transmission meet the requirements, and the carbon equivalent CEPcm in the steel is ≤0.19.

[0029] The production process sequence is as follows: pipe blank heating, piercing, continuous rolling, sizing, cooling, sawing, heat treatment, flaw detection, water pressure, manual inspection and detection analysis.

[0030] The specific production process sequence is briefly described as follows:

[0031] 1. The chemical composition and quality of the L360QH seamless steel pipe blank for hydrogen transmission meet the requirements, and the carbon equivalent CEPcm in the steel is ≤0.19.

[0032] 2. The pipe blank is loaded into the annular heating furnace, and is heated through three sections of preheating section, heating section and soaking section, the preheating section temperature is 650-900℃, the heating section temperature is 900-1180℃, and the soaking section temperature is 1200-1240℃.

[0033] 3. The circular billet is sent into the annular heating furnace, and then into the piercing mill to ensure the consistency of the piercing mill body and the rolling center line of the front and rear stands, and the temperature after piercing is ≥1130℃.

[0034] 4. The pierced hollow billet is sent into the Ф460mm PQF hot continuous rolling mill to ensure that the temperature of the hollow billet before entering the continuous rolling mill is ≥950℃.

[0035] 5. According to the different wall thicknesses of the steel pipes, different numbers of stands are selected for sizing to ensure that the temperature of the steel pipe after sizing is ≥850℃.

[0036] 6. After the steel pipe exits the sizing mill, it is air-cooled on the cooling bed until room temperature, and then sawn, inspected, and artificially inspected.

[0037] 7. The hot-rolled seamless steel pipe with qualified appearance size is subjected to quenching and tempering heat treatment, the temperature of the heating furnace holding section is 920±10℃, the holding time is 5-10 minutes, the heating temperature of the tempering furnace is 680±10℃, the holding time is 5-10 minutes, and then the pipe is discharged and air-cooled.

[0038] 8. After heat treatment, the seamless steel pipe is subjected to straightening, inspection, water pressure, sampling, and related tests. The sampling is subjected to chemical composition and mechanical property detection and analysis.

[0039] The offline normalizing process is used to produce the L360QH seamless steel pipe for hydrogen transportation with the specification of Ф273.1mm×7.1mm×12000mm (Example 1), Ф406.4mm×12.7mm×12000mm (Example 2), and Ф457mm×9.5mm×11500mm (Example 3), and the sampling inspection is carried out. The chemical composition test results (weight percentage content) are shown in Table 2, the mechanical property test results are shown in Table 3, the metallographic property test results are shown in Table 4, and the microstructure photos are shown in Figures 1-3 .

[0040] Table 2 Chemical composition test results of L360QH pipe billet (wt%)

[0041] C Si Mn P S Cr Mo V Ti CE pcm ]] Example 0.061 0.27 1.17 0.011 0.002 0.20 0.12 0.03 0.013 0.115 Example 0.057 0.28 1.19 0.013 0.002 0.21 0.13 0.03 0.011 0.119 Example 0.063 0.29 1.20 0.010 0.003 0.21 0.11 0.03 0.012 0.118

[0042] Table 3 Mechanical property test results of L360QH seamless steel pipe

[0043]

[0044] Table 4 Metallographic property test results of L360QH seamless steel pipe (grade)

[0045]

[0046] The above described embodiments are only to illustrate the preferred modes of the present application, and are not intended to limit the scope of the present application. Any modification and improvement made by those skilled in the art to the technical solutions of the present application without departing from the design spirit of the present application shall fall within the protection scope of the present application.

Claims

1. A method of manufacturing a super low carbon L360QH seamless steel pipe for hydrogen transport, characterized by: The seamless steel pipe has the following chemical composition in percentage by mass: C 0.05-0.063%, Si 0.25-0.35%, Mn 1.15-1.22%, P≤0.010%, S≤0.003%, Cr 0.18-0.28%, Mo 0.10-0.13%, V 0.02-0.04%, Ti 0.01-0.02%, and the rest is Fe and inevitable impurities; The manufacturing method comprises: 1) producing a seamless steel pipe blank for hydrogen transportation with qualified chemical composition and mass, so that the carbon equivalent in the steel is less than or equal to 0.19; 2) loading the pipe blank into an annular heating furnace, and heating through three sections of preheating section, heating section and soaking section, the preheating section temperature is 650-900℃, the heating section temperature is 900-1180℃, and the soaking section temperature is 1200-1240℃; 3) sending the pipe blank out of the annular heating furnace and into a piercer for piercing, ensuring that the piercing machine body and the front and rear stations are consistent in rolling center line, and ensuring that the temperature after piercing is greater than or equal to 1130℃; 4) sending the pierced pipe into a Φ460mm PQF hot continuous rolling mill for continuous rolling, ensuring that the temperature of the pipe before entering the continuous rolling mill is greater than or equal to 950℃; 5) selecting different rack numbers for the pipe according to the different wall thicknesses of the pipe, and ensuring that the temperature of the pipe after sizing is greater than or equal to 850℃; 6) after the pipe comes out of the sizing mill, the pipe is air-cooled on a cooling bed until room temperature, and then sawing, flaw detection and manual inspection are performed; 7) performing quenching and tempering heat treatment on the hot-rolled seamless steel pipe with qualified appearance size, the temperature of the heating furnace holding section is 920±10℃, the holding time is 5-10 minutes, the heating temperature of the tempering furnace is 680±10℃, the holding time is 5-10 minutes, and then the pipe is taken out of the furnace and air-cooled; 8) after the heat treatment, the pipe is straightened, detected, water-pressured, sampled and subjected to relevant tests; the sampling is subjected to detection and analysis of chemical composition and mechanical properties.

2. The method of producing a super low carbon L360QH seamless steel pipe for hydrogen transport according to claim 1, characterized by: The seamless steel pipe has the following chemical composition in percentage by mass: C 0.063%, Si 0.29%, Mn 1.20%, P 0.010%, S 0.003%, Cr 0.21%, Mo 0.11%, V 0.03%, Ti 0.012%, and the rest is Fe and inevitable impurities.

3. The method of producing a super low carbon L360QH seamless steel pipe for hydrogen transport according to claim 1, characterized by: The yield ratio of the manufactured seamless steel pipe satisfies less than or equal to 0.6.

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