Manufacturing method of X52QS long-distance conveying seamless line pipe with high toughness and H2S corrosion resistance at extremely cold temperature

Abstract

The invention discloses a manufacturing method of an X52QS long-distance conveying seamless line pipe with high toughness and H2S corrosion resistance at an extremely cold temperature, and belongs to the technical field of ferrous metal pressure processing. The steel comprises the following chemical components in percentage by weight: 0.6 to 0.12 percent of C, 0.20 to 0.40 percent of Si, 0.80 to 1.20 percent of Mn, 0.02 to 0.04 percent of V, 0.005 to 0.020 percent of Ti, 0.015 to 0.040 percent of Al, less than or equal to 0.018 percent of P, less than or equal to 0.003 percent of S and the balance of Fe and impurity elements. The invention further discloses a specific manufacturing process. According to the invention, ultra-low carbon is matched with a proper Mn element, and a small amount of microalloying element V is added, and through quenching and tempering heat treatment, the technical requirements of H2S corrosion resistant X52QS seamless pipeline steel pipe for long-distance transportation at extremely cold temperature are met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ferrous metal pressure processing, and particularly relates to a manufacturing method of high-toughness H2S corrosion-resistant X52QS long-distance conveying seamless pipeline pipe under extremely cold temperature. BACKGROUND

[0002] Under the background of the continuous development of the global economy, the demand for energy is showing a sustained upward trend. As extremely critical energy resources, the long-distance transportation of oil and natural gas is self-evident. Many oil and natural gas contain H2S with strong corrosive properties, which can easily cause acid corrosion to the pipeline during the conveying process. At present, the pipeline pipe that can adapt to extremely cold temperature environment and has high toughness and resistance to hydrogen sulfide corrosion is mostly made of hot-rolled plate coil steel. In comparison, seamless pipe has obvious advantages in thick-walled pipe manufacturing, high-strength pipe production, medium-high alloy material processing, corrosion-resistant pipe manufacturing, and small-batch customized production, and can better meet the actual needs of specific pipeline engineering projects. Therefore, the pipeline pipe must have the ability to maintain high toughness in extremely cold environments and resist hydrogen sulfide corrosion. However, in reality, pipeline pipe corrosion, cracking and other problems occur frequently during long-distance conveying, which not only greatly increases the maintenance cost of the pipeline, but also poses a serious threat to the safety and stability of energy transportation. Therefore, it is urgent to develop a new manufacturing method, which has very important practical significance for meeting the growing demand for long-distance conveying of X52QS seamless pipeline pipe resistant to hydrogen sulfide in extremely cold environments in the energy field. SUMMARY

[0003] The application aims to provide a manufacturing method of high-toughness H2S corrosion-resistant X52QS long-distance conveying seamless pipeline pipe under extremely cold temperature, which uses low-C steel with appropriate Mn elements, adds a small amount of micro-alloying elements V and Ti, and produces the seamless pipeline pipe that meets the demand for high-toughness H2S corrosion-resistant X52QS long-distance conveying under extremely cold temperature through quenching + tempering heat treatment.

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

[0005] The application discloses a manufacturing method of high-toughness H2S corrosion-resistant X52QS long-distance conveying seamless pipeline pipe under extremely low temperature, and the chemical composition of the seamless pipeline pipe is as follows: C: 0.06-0.12%, Si: 0.20-0.40%, Mn: 0.80-1.20%, V: 0.02-0.04%, Ti: 0.005-0.020%, Al: 0.005-0.040%, P: ≤0.018%, S: ≤0.003%, and the rest is Fe and impurity elements; the manufacturing method comprises the following steps: adopting the continuously-cast round pipe blank of the high-toughness H2S corrosion-resistant X52QS long-distance conveying seamless pipeline pipe under extremely low temperature which meets the above component requirements, and performing the following manufacturing process: ring furnace heating, piercing machine piercing, PQF hot continuous rolling, pipe removing, sizing, cold bed cooling, saw cutting, straightening, quenching and tempering heat treatment, flaw detection, water pressure and packaging and warehousing; and the specific steps are as follows:

[0006] The continuously-cast round pipe blank meeting the component requirements is heated in the ring furnace, and the heating temperature of each section of the ring furnace is as follows: 900-1000 DEG C for the first heating section, 1000-1100 DEG C for the second heating section, 1100-1250 DEG C for the third heating section, 1250-1280 DEG C for the fourth heating section, 1250-1280 DEG C for the fifth heating section and 1250-1280 DEG C for the sixth heating section, and the holding time is 5±0.5 hours;

[0007] After the round pipe blank is heated in the ring furnace, the round pipe blank is sent to the plug-type piercing machine to perform piercing, and the piercing temperature is 1200-1250 DEG C; the rough steel pipe formed by piercing is transferred to the φ460 PQF continuous rolling mill to perform rolling, and the rolling temperature is 950-1200 DEG C;

[0008] The steel pipe of the required specification which is formed by hot continuous rolling is subjected to quenching + tempering heat treatment process: firstly, quenching treatment is performed, the quenching temperature is set to be 910 DEG C ± 10 DEG C, and after the steel pipe reaches the temperature, the pure holding time is kept for more than 10 minutes; the quenching process adopts the mode of internal spraying and external spraying, and the cooling medium is water; after the quenching process is completed, the tempering stage is entered, the tempering temperature is controlled to be 630 DEG C ± 10 DEG C, the steel pipe is kept for pure holding for 10-20 minutes after reaching the tempering temperature, and finally, the furnace is discharged to perform air cooling.

[0009] Further, the chemical composition of the seamless pipeline pipe is as follows: C: 0.06%, Si: 0.20%, Mn: 0.80%, V: 0.02%, Ti: 0.005%, Al: 0.005%, P: 0.018%, S: 0.003%, and the rest is Fe and impurity elements.

[0010] Further, the seamless pipeline pipe has the following chemical composition in percentage by mass: C: 0.08%, Si: 0.25%, Mn: 0.90%, V: 0.03%, Ti: 0.008%, Al: 0.015%, P: 0.016%, S: 0.002%, and the rest is Fe and impurities.

[0011] Further, the seamless pipeline pipe has the following chemical composition in percentage by mass: C: 0.09%, Si: 0.30%, Mn: 1.00%, V: 0.02%, Ti: 0.011%, Al: 0.025%, P: 0.014%, S: 0.003%, and the rest is Fe and impurities.

[0012] Further, the seamless pipeline pipe has the following chemical composition in percentage by mass: C: 0.10%, Si: 0.35%, Mn: 1.10%, V: 0.03%, Ti: 0.015%, Al: 0.035%, P: 0.018%, S: 0.002%, and the rest is Fe and impurities.

[0013] Further, the seamless pipeline pipe has the following chemical composition in percentage by mass: C: 0.12%, Si: 0.40%, Mn: 1.20%, V: 0.04%, Ti: 0.020%, Al: 0.040%, P: 0.010%, S: 0.003%, and the rest is Fe and impurities.

[0014] Further, the impact energy of the steel grade-45℃ transverse full-size sample reaches 160J or above.

[0015] Compared with the prior art, the present application has the following beneficial technical effects:

[0016] In the steel material, C-Mn is the most effective and economic element combination to improve the strength. At the same time, low carbon content is a key measure to control the low-temperature toughness of the pipeline pipe, and the carbon content is negatively correlated with the low-temperature impact toughness, that is, the lower the carbon content, the better the low-temperature impact toughness. Therefore, appropriately reducing the carbon content and matching a certain amount of manganese and adding a small amount of micro-alloying elements V and Ti can effectively balance the impact toughness in the low-temperature environment. V-Ti micro-alloying can significantly optimize the performance of the steel, V can precipitate carbonitride in the steel, effectively pin the dislocation, hinder the grain growth, and improve the strength. Ti can refine the grain of the casting blank, improve the organization of the steel, and the two are synergistic, which not only enhances the strength, but also improves the toughness and welding performance. The hot-rolled steel pipe adopts a quenching and tempering heat treatment process, and a good matching effect of high strength and toughness is obtained. DETAILED DESCRIPTION

[0017] The present application will be described in detail below through specific embodiments.

[0018] The φ390mm round pipe blank satisfying the chemical composition requirement of the application is rolled into a steel pipe with a specification of φ355.6mm*15.88mm, and then quenched and tempered.

[0019] The production process flow is as follows: ring furnace heating→piercing machine piercing→PQF hot rolling→tube removal→sizing→cold bed cooling→saw cutting→straightening→quenching and tempering heat treatment→flaw detection→water pressure→packing into warehouse.

[0020] The specific production process flow is briefly described as follows:

[0021] 1. The heating temperature of the φ390mm continuous casting round pipe blank in the ring furnace is as follows: 900-1000℃ for the first heating section, 1000-1100℃ for the second heating section, 1100-1250℃ for the third heating section, 1250-1280℃ for the fourth heating section, 1250-1280℃ for the fifth heating section, and 1250-1280℃ for the sixth heating section. The holding time is 5±0.5 hours.

[0022] 2. The continuous casting round pipe blank heated in the ring furnace is pierced in the ring-type piercing machine, and the piercing temperature is 1200-1250℃.

[0023] 3. The pierced rough pipe is blown with an appropriate amount of borax to ensure that the borax is evenly lubricated on the entire inner surface of the steel pipe without caking. The rough pipe after borax blowing is moved to the φ460mm PQF continuous rolling pipe unit for rolling, and the rolling temperature is controlled to be 950-1200℃. The center line of the rolling mill is kept aligned during the hot continuous rolling process, the hole types of each rack are reasonably distributed, and the EMS online size monitoring system is used to ensure the size precision requirements of the steel pipe. The rough pipe after hot continuous rolling is subjected to sizing in the sizing machine to reach the required finished pipe size.

[0024] 4. The finished steel pipe after the sizing machine is naturally cooled on the cold bed, and then sawn into the required steel pipe length.

[0025] 5. The steel pipe of the required specification after hot rolling is subjected to quenching and tempering heat treatment, the quenching temperature is set to be 910℃±10℃, the pure holding time is maintained for more than 10 minutes, the quenching is performed by the inner spraying and outer spraying method, and the cooling medium is water. After quenching, the pipe is subjected to tempering in the tempering furnace, the tempering temperature is controlled to be 630℃±10℃, the pure holding time is 15 minutes, and then the pipe is taken out of the furnace for air cooling, flaw detection, water pressure, chamfering, and material physical and chemical property detection before being packed into the warehouse.

[0026] The chemical composition, tensile strength, and -45℃ low-temperature impact of five different embodiments of the φ355.6mm*15.88mm seamless pipe line pipe for X52QS long-distance transportation under extremely cold temperature and high toughness and H2S corrosion resistance produced by the above process are tested, and the actual test data are shown in Tables (1) and (2).

[0027] Table 1 Chemical composition of 5 examples (wt%)

[0028]

[0029] Table 2 Tensile impact performance of 4 examples

[0030]

[0031]

[0032] Results and discussion: From the table (1), (2) can be seen, 5 examples of finished chemical composition meet the requirements of the present application, through quenching + tempering treatment, φ355.6x15.88 H2S corrosion resistance X52QS seamless line pipe of 5 tensile properties can meet the API 5L standard for X52QS provisions, the composition design of steel is reasonable, only on the basis of low C-Mn steel to add a small amount of micro-alloying elements V-Ti can meet the requirements, the cost of steel is economic and reasonable, especially-45℃ transverse full-size sample impact energy reached 160J above, shear area ratio is 100%, the X52QS low temperature toughness of the present application is good, can meet the performance requirements of high toughness anti-sulfur hydrogen corrosion X52QS long distance conveying seamless line pipe under extremely cold temperature conditions.

[0033] The above-described examples are only preferred ways of the present application, and are not intended to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A method for manufacturing X52QS long-distance transportation seamless pipeline with high toughness and H2S corrosion resistance at extremely cold temperatures, characterized by: The chemical composition of the seamless line pipe by mass percentage is: C: 0.06-0.12%, Si: 0.20-0.40%, Mn: 0.80-1.20%, V: 0.02-0.04%, Ti: 0.005-0.020%, Al: 0.005-0.040%, P: ≤0.018%, S: ≤0.003%, and the rest is Fe and impurity elements; The manufacturing method includes: The continuously cast round tube billet that meets the composition requirements is heated in a ring furnace. The ring furnace is divided into 6 sections, and the heating temperature of each section is as follows: heating section 1: 900℃~1000℃, heating section 2: 1000℃-1100℃, heating section 3: 1100℃-1250℃, heating section 4: 1250℃-1280℃, heating section 5: 1250℃-1280℃, heating section 6: 1250℃-1280℃, and the holding time is 5±0.5 hours; After the round tube billet is heated in the annular furnace, it is sent to the mushroom-type piercing machine for piercing at a temperature of 1200℃~1250℃. The rough steel tube formed by piercing is transferred to the φ460PQF continuous rolling mill for rolling at a temperature of 950℃~1200℃. The steel pipes produced by hot rolling to the required specifications are subjected to quenching + tempering heat treatment process: first, quenching treatment is carried out, and the quenching temperature is set to 910℃±10℃. After the steel pipe reaches this temperature, it is kept at this temperature for more than 10 minutes; the quenching process adopts the method of internal spraying and external showering, and the cooling medium is water; after quenching is completed, it enters the tempering stage, and the tempering temperature is controlled at 630℃±10℃. After the steel pipe reaches the tempering temperature, it is kept at this temperature for 10-20 minutes, and finally it is taken out of the furnace for air cooling.

2. The method for manufacturing X52QS long-distance transportation seamless line pipe with high toughness and H2S corrosion resistance under extremely cold temperatures according to claim 1 is characterized in that: The chemical composition of the seamless line pipe in mass percentage is: C: 0.06%, Si: 0.20%, Mn: 0.80%, V: 0.02%, Ti: 0.005%, Al: 0.005%, P: 0.018%, S: 0.003%, and the rest is Fe and impurity elements.

3. The method for manufacturing X52QS long-distance transportation seamless line pipe with high toughness and H2S corrosion resistance under extreme cold temperatures according to claim 1, characterized in that: The chemical composition of the seamless line pipe in mass percentage is: C: 0.08%, Si: 0.25%, Mn: 0.90%, V: 0.03%, Ti: 0.008%, Al: 0.015%, P: 0.016%, S: 0.002%, and the rest is Fe and impurity elements.

4. The method for manufacturing X52QS long-distance transportation seamless line pipe with high toughness and H2S corrosion resistance under extreme cold temperatures according to claim 1 is characterized in that: The chemical composition of the seamless line pipe in mass percentage is: C: 0.09%, Si: 0.30%, Mn: 1.00%, V: 0.02%, Ti: 0.011%, Al: 0.025%, P: 0.014%, S: 0.003%, and the rest is Fe and impurity elements.

5. The method for manufacturing X52QS long-distance transportation seamless line pipe with high toughness and H2S corrosion resistance under extreme cold temperatures according to claim 1 is characterized in that: The chemical composition of the seamless line pipe in mass percentage is: C: 0.10%, Si: 0.35%, Mn: 1.10%, V: 0.03%, Ti: 0.015%, Al: 0.035%, P: 0.018%, S: 0.002%, and the rest is Fe and impurity elements.

6. The method for manufacturing X52QS long-distance transportation seamless line pipe with high toughness and H2S corrosion resistance under extreme cold temperatures according to claim 1, characterized in that: The chemical composition of the seamless line pipe in mass percentage is: C: 0.12%, Si: 0.40%, Mn: 1.20%, V: 0.04%, Ti: 0.020%, Al: 0.040%, P: 0.010%, S: 0.003%, and the rest is Fe and impurity elements.

7. The method for manufacturing X52QS long-distance transportation seamless line pipe with high toughness and H2S corrosion resistance under extreme cold temperatures according to any one of claims 1 to 6, characterized in that: The impact energy of the full-size transverse specimens of the steel grade at -45℃ reached more than 160J.

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