Steel for hydrogen transmission pipeline and production method thereof

Abstract

The invention discloses steel for a hydrogen transmission pipeline and a production method of the steel, and belongs to the technical field of ferrous metallurgy, the steel comprises the following chemical components in percentage by mass: 0.03%-0.05% of C, 0.15%-0.35% of Si, 0.7%-1.30% of Mn, less than or equal to 0.015% of P, less than or equal to 0.0010% of S, 0.010%-0.030% of Nb, 0.035%-0.055% of V, 0.008%-0.030% of Ti, 0.15%-0.35% of Cr, 0.30%-0.50% of Ni, 0.050%-0.150% of Mo, 0.10%-0.20% of Cu, 0.010%-0.050% of Al, less than or equal to 0.00050% of B, less than or equal to 0.0060% of N, less than or equal to 0.0002% of According to the production method, high-purity low-carbon phosphorus-sulfur molten steel is obtained through a converter, refining and continuous casting, alloy steel mainly comprising acicular ferrite is obtained through a hot mechanical rolling technology, and the hydrogen conveying requirement of products is met.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of steel and its production method, specifically relates to a kind of steel for hydrogen pipeline and its production method, belong to steel metallurgy technical field. BACKGROUND

[0002] There are few hydrogen pipelines in the world, and the existing hydrogen pipelines are mainly used for transporting chemical hydrogen raw materials. The first hydrogen pipeline was built in the Ruhr industrial area of Germany in 1938, with a total length of about 208 km, a pipe diameter of 150-300 mm and a design pressure of 2.5 MPa. The existing hydrogen pipeline network system in the world includes the United States, Germany, the United Kingdom, Canada, Italy and other countries, with a total length of about 6000 km.

[0003] In 1875, Johnson first proposed hydrogen embrittlement. Since the atomic number of hydrogen is very small, many characterization methods cannot capture the specific location of its existence. However, for nearly a century, researchers have been constantly exploring the hydrogen embrittlement behavior and mechanism in metals and have proposed several possible hydrogen embrittlement mechanisms. The widely accepted theory is hydrogen pressure theory, hydrogen-induced weak bond theory and hydrogen-promoted local plastic deformation theory. This view believes that hydrogen atoms recombine and aggregate at defects, and combine to form hydrogen molecules. After hydrogen atoms combine to form hydrogen molecules, the hydrogen concentration in the trap decreases. Under the influence of concentration gradient, hydrogen atoms in the lattice gap around the trap will continue to move to the trap position. More hydrogen atoms will produce more hydrogen molecules. When the local pressure exceeds the yield stress, cracks will nucleate, and the stress concentration at the tip will accelerate the propagation of cracks, eventually leading to HIC disqualification. How to improve the strength of steel plate without changing the microstructure type and improve the hydrogen embrittlement resistance is a problem to be solved for hydrogen pipeline steel plate.

[0004] The current patent CN118460928A high-strength level hydrogen pipeline steel plate and its rolling method and application improves the tensile strength of the steel plate to 560-589 MPa by optimizing the design of the alloy and the rolling process. While improving the strength level of the hot-rolled plate, the number and uniformity of hydrogen traps are significantly improved, and the hydrogen embrittlement resistance is improved. However, its tensile strength still needs to be improved. The patent CN116408349A low-cost yield strength 360 MPa grade hydrogen-doped gas pipeline hot-rolled plate coil industrial manufacturing method does not add V, Cu, Cr, Ni to the composition, and the composition is not optimized. The performance is poor.

[0005] Therefore, a suitable alloy design method for hydrogen environment is developed, and a reliable manufacturing step is provided to meet the requirements of hydrogen-induced crack resistance of the product and overcome the above technical problems. The hydrogen pipeline steel and its production method become a technical problem to be solved by the person skilled in the art. SUMMARY

[0006] The technical problem solved by the present application is to overcome the defects of the prior art and provide a hydrogen pipeline steel and a production method thereof.

[0007] To solve the above technical problem, the present application provides a hydrogen pipeline steel, which has the following chemical components in percentage by mass: C: 0.03% to 0.05%, Si: 0.15% to 0.35%, Mn: 0.7% to 1.30%, P≤0.015%, S≤0.0010%, Nb: 0.010% to 0.030%, V: 0.035% to 0.055%, Ti: 0.008% to 0.030%, Cr: 0.15% to 0.35%, Ni: 0.30% to 0.50%, Mo: 0.050% to 0.150%, Cu: 0.10% to 0.20%, Al: 0.010% to 0.050%, B≤0.00050%, N≤0.0060%, H≤0.0002%, and the balance of Fe and inevitable impurities, and the sum of the above components is 100%.

[0008] The further defined technical solution of the present application is:

[0009] Further, the hydrogen pipeline steel has the following chemical components in percentage by mass: C: 0.04% to 0.05%, Si: 0.25% to 0.35%, Mn: 0.9% to 1.30%, P≤0.015%, S≤0.0010%, Nb: 0.020% to 0.030%, V: 0.045% to 0.055%, Ti: 0.010% to 0.030%, Cr: 0.25% to 0.35%, Ni: 0.40% to 0.50%, Mo: 0.10% to 0.15%, Cu: 0.10% to 0.20%, Al: 0.010% to 0.050%, B≤0.00050%, N≤0.0060%, H≤0.0002%, and the balance of Fe and inevitable impurities, and the sum of the above components is 100%.

[0010] The chemical composition of the aforementioned hydrogen transmission pipeline steel is as follows in terms of mass percentage: C: 0.03%-0.04%, Si: 0.15%-0.25%, Mn: 0.7%-1.10%, P≤0.013%, S≤0.0010%, Nb: 0.010%-0.020%, V: 0.035%-0.045%, Ti: 0.008%-0.020%, Cr: 0.15%-0.25%, Ni: 0.30%-0.40%, Mo: 0.05%-0.10%, Cu: 0.10%-0.15%, Al: 0.010%-0.040%, B≤0.00050%, N≤0.0060%, H≤0.0002%, the balance being Fe and inevitable impurities, and the sum of the above components being 100%.

[0011] The application also designs a production method of the hydrogen transmission pipeline steel, specifically including the following steps:

[0012] S1, after desulfurization, the molten iron is sent to a converter for smelting, top and bottom combined blowing smelting is adopted, the oxygen gun oxygen supply flow is 14500-15500 Nm 3 / h, and the bottom stirring flow is set to 100-150 Nm 3 / h;

[0013] S2, the smelting period is 35-45 min, the converter tapping temperature is 1660-1700 DEG C, and the temperature composition meets the requirements to perform the converter tapping operation;

[0014] S3, the molten steel is sent to an LF for refining for the first time, a power slag is provided for alloying treatment, and after the alloying treatment, the RH is used for vacuum treatment, the high vacuum degree holding time is 20-30 min, the vacuum fine stirring is 10-20 min, and after the temperature meets the requirements, the continuous casting is used for pouring;

[0015] S4, full-process argon protection pouring is adopted, the pouring speed is 0.6-1.3 m / min, the pouring superheat is 10-20 DEG C, a water spraying cooling zone is adopted to ensure uniform and stable cooling;

[0016] S5, after the billet surface inspection is qualified, the billet is sent to a heating furnace for heating, the heating temperature is 1180-1260 DEG C, a two-stage rolling process is adopted, the second opening temperature is 800-900 DEG C, the final rolling temperature is 770-830 DEG C, the water entry temperature is 750-800 DEG C, and the red return is 400-600 DEG C;

[0017] S6, the cooled steel plate is subjected to stack cooling, shearing, marking and warehousing.

[0018] The application is further limited by the technical scheme:

[0019] In the aforementioned production method of the hydrogen transmission pipeline steel, the produced steel plate has a thickness of 5-50 mm.

[0020] The production method of the aforementioned hydrogen delivery pipeline steel produces a product steel grade of X60M to X70M, and the performance meets the requirements of the API standard.

[0021] The beneficial effects of the present application are:

[0022] (1) The present application adopts a BOF-LF-RH smelting process, reduces the harmful gas content of the molten steel, improves the cleanliness of the molten steel, reduces the influence of the impurity element content in the intergranular gap on the HIC performance, and improves the hydrogen-induced cracking resistance;

[0023] (2) The present application optimizes the alloying elements, controls Cr: 0.15-0.35%, Ni: 0.30%-0.50%, Mo: 0.050%-0.150%, Cu: 0.10%-0.20%, improves the use of chromium-nickel-molybdenum-copper alloy, and ensures the strength of the steel plate through alloy strengthening. Because of the use of alloying elements, the stability of acicular ferrite during the transformation of the structure is ensured, the intergranular structure strengthening is strengthened, the possibility of hydrogen-induced cracking at the intergranular gap is avoided, and the stability of the HIC performance of the product is improved;

[0024] (3) The use of ultra-low carbon design is beneficial to improving low-temperature toughness, improving welding performance and cold bending forming. The low-carbon design reduces the proportion of hard structures, which is beneficial to improving the stability of the HIC and SSC performance of the product. The combined use of niobium, vanadium and titanium can realize dual reinforcement of fine grain and precipitation strengthening, ensure the stability of the product strength and the stability of the structure grain, and greatly improve the HIC and SSC performance through the combined use of grain stability. Aluminum elements not only effectively remove free oxygen elements in the molten steel, but also can precipitate micron-level AlN particles in the austenite zone, pin the grain boundary, further refine the austenite grain, and the tightly combined grain structure can improve the HIC and SSC performance. Through the Ni-Mo-Cr-Cu alloying design, the use of valuable alloys Nb and V is reduced. The combined use not only improves the hardenability, but also expands the austenite zone to improve the low-temperature toughness, and forms a Cr2O3 passivation film / dense Cu2O / CuO oxide film to improve the acid and corrosion resistance of the product.

[0025] (4) The present application adopts top and bottom combined blowing smelting during converter smelting, and the oxygen gun oxygen supply flow is 14500-15500 Nm 3 / h, the bottom stirring flow is set to 100-150 Nm 3 / h, the stability of the converter oxygen supply intensity and the bottom stirring effect is improved, the decarburization capacity of the converter is improved, the converter tapping temperature is increased to 1660-1700℃, and the purpose of reducing carbon and sulfur is achieved.

[0026] (5) The rolling process adopts high temperature 1180-1260℃ heating and low temperature 770-830℃ rolling process, which effectively improves the rolling pass reduction rate, improves the influence of the microstructure gap on the HIC performance through large reduction technology, stabilizes the mechanical properties of the product, and makes the transverse tensile properties, yield strength reach 490MPa, tensile strength reach 623MPa, elongation rate is 45%, and the yield strength ratio is 84. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The near-surface metallographic structure diagram of the hydrogen pipeline steel in embodiment 1 of the present application. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0029] Embodiment 1

[0030] The hydrogen pipeline steel provided in the embodiment has the following chemical components in percentage by mass: C: 0.043%, Si: 0.31%, Mn: 0.97%, P: 0.013%, S: 0.0008%, Nb: 0.028%, V: 0.049%, Ti: 0.017%, Cr: 0.29%, Ni: 0.43%, Mo: 0.14%, Cu: 0.16%, Al: 0.028%, B: 0.00020%, N: 0.0036%, H: 0.0001%, and the balance of Fe and inevitable impurities, and the sum of the above components is 100%.

[0031] The production method of the hydrogen pipeline steel described above, and the steel plate thickness is 32mm, specifically includes the following steps:

[0032] S1, after the molten iron is desulfurized, it is sent to a converter for smelting, top and bottom combined blowing smelting is adopted, the oxygen gun oxygen supply flow is 14900Nm 3 / h, the bottom stirring flow is set to 140Nm 3 / h;

[0033] S2, the smelting cycle is 39min, the converter tapping temperature is 1675℃, and the temperature composition meets the requirements for converter tapping operation;

[0034] S3, the molten steel is sent to LF for refining at the first time, the electric slag is provided for alloying treatment, after the alloying treatment, the RH is sent for vacuum treatment, the high vacuum degree holding time is 27 min, the vacuum refining stirring time is 13 min, after the temperature meets the requirements, the continuous casting is sent for pouring;

[0035] S4, the whole process is protected by argon, the pouring speed is 0.8 m / min, the pouring superheat is 17 DEG C, the water cooling zone is used to ensure the uniform and stable cooling;

[0036] S5, after the billet surface inspection is qualified, the billet is sent to the heating furnace for heating, the heating temperature is 1230 DEG C, the two-stage rolling process is used, the second opening temperature is 878 DEG C, the final rolling temperature is 830 DEG C, the water inlet temperature is 790 DEG C, and the red return temperature is 570 DEG C;

[0037] S6, the cooled steel plate is subjected to stack cooling, shearing, marking and warehousing.

[0038] The thickness 1 / 4 metallographic structure of the steel plate produced in example 1 is as shown in Figure 1 .

[0039] Example 2

[0040] The steel provided in the embodiment is used for hydrogen transmission pipeline, and the chemical components of the steel are as follows in terms of mass percentage: C: 0.038%, Si: 0.19%, Mn: 0.89%, P: 0.011%, S: 0.0009%, Nb: 0.030%, V: 0.039%, Ti: 0.019%, Cr: 0.17%, Ni: 0.37%, Mo: 0.09%, Cu: 0.13%, Al: 0.038%, B: 0.00010%, N: 0.0044%, H: 0.0001%, and the balance is Fe and inevitable impurities, and the sum of the above components is 100%.

[0041] The production method of the hydrogen transmission pipeline steel is as follows:

[0042] S1, after the molten iron is desulfurized, the molten iron is sent to the converter for smelting, the top and bottom combined blowing smelting is used, the oxygen gun oxygen supply flow is 15000 Nm 3 / h, and the bottom stirring flow is set to 140 Nm 3 / h;

[0043] S2, the smelting cycle is 41 min, the converter tapping temperature is 1680 DEG C, and the temperature composition meets the requirements for the converter tapping operation;

[0044] S3, the molten steel is sent to LF for refining at the first time, the electric slag is provided for alloying treatment, after the alloying treatment, the RH is sent for vacuum treatment, the high vacuum degree holding time is 27 min, the vacuum refining stirring time is 13 min, after the temperature meets the requirements, the continuous casting is sent for pouring;

[0045] S4, adopt argon protection pouring throughout the process, pouring speed 0.9m / min, pouring superheat 19℃, use water spray cooling zone to ensure uniform and stable cooling;

[0046] S5. After the billet passes the surface inspection, it is sent to the heating furnace for heating at a temperature of 1190°C. A two-stage rolling process is adopted, with a second rolling temperature of 890°C, a final rolling temperature of 790°C, a water entry temperature of 790°C, and a return to redness of 580°C.

[0047] S6. The cooled steel plates are stacked, sheared, marked and stored.

[0048] The mechanical properties of the steel plates produced in Examples 1-2 were tested using existing technology, as shown in Tables 1 and 2.

[0049] Table 1 Transverse and longitudinal tensile properties

[0050] Example Direction Yield strength (MPa) Tensile strength (MPa) Elongation (%) Yield strength ratio Example 1 Transverse 470 560 43 84 Example 2 Transverse 490 623 45 79

[0051] Table 2 Low temperature impact toughness at -20℃, -20℃ DWTT performance, HIC and SSCC test data

[0052] Example Impact average (-20°C) DWTT (-20°C) Hardness HIC Example 1 432J 95 216 Pass Example 2 415J 96 209 Pass

[0053] The present invention obtains high-purity low-carbon, phosphorus-sulfur molten steel through converter, refining and continuous casting, and adopts thermomechanical rolling technology to obtain alloy steel mainly composed of acicular ferrite, which has good performance and meets the hydrogen transport requirements of the product.

[0054] In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection required by the present invention.

Claims

1. A steel for hydrogen pipeline, characterized in that: The chemical composition of the steel is as follows in mass percentage: C: 0.03%~0.05%, Si: 0.15%~0.35%, Mn: 0.7%~1.30%, P≤0.015%, S≤0.0010%, Nb: 0.010%~0.030%, V: 0.035%~0.055%, Ti: 0.008%~0.030%, Cr: 0.15%~0.35%, Ni: 0.30%~0.50%, Mo: 0.050%~0.150%, Cu: 0.10%~0.20%, Al: 0.010%~0.050%, B≤0.00050%, N≤0.0060%, H≤0.0002%, the balance is Fe and unavoidable impurities, and the sum of the above components is 100%.

2. The steel for hydrogen pipeline according to claim 1, characterized in that: The chemical composition of the steel is as follows in mass percentage: C: 0.04%~0.05%, Si: 0.25%~0.35%, Mn: 0.9%~1.30%, P≤0.015%, S≤0.0010%, Nb: 0.020%~0.030%, V: 0.045%~0.055%, Ti: 0.010%~0.030%, Cr: 0.25%~0.35%, Ni: 0.40%~0.50%, Mo: 0.10%~0.15%, Cu: 0.10%~0.20%, Al: 0.010%~0.050%, B≤0.00050%, N≤0.0060%, H≤0.0002%, the remainder is Fe and unavoidable impurities, and the sum of the above components is 100%.

3. The steel for hydrogen pipeline according to claim 1, characterized in that: The chemical composition of the steel is as follows in mass percentage: C: 0.03%~0.04%, Si: 0.15%~0.25%, Mn: 0.7%~1.10%, P≤0.013%, S≤0.0010%, Nb: 0.010%~0.020%, V: 0.035%~0.045%, Ti: 0.008%~0.020%, Cr: 0.15%~0.25%, Ni: 0.30%~0.40%, Mo: 0.05%~0.10%, Cu: 0.10%~0.15%, Al: 0.010%~0.040%, B≤0.00050%, N≤0.0060%, H≤0.0002%, the balance is Fe and unavoidable impurities, and the sum of the above components is 100%.

4. A method for producing steel for hydrogen pipelines according to any one of claims 1 to 3, characterized in that: The specific steps include: S1. After desulfurization, the molten iron is sent to the converter for smelting. Top and bottom combined blowing is adopted. The oxygen flow rate of the oxygen lance is 14500~15500Nm 3 / h, bottom stirring flow rate is set to 100~150Nm 3 / h; S2, smelting cycle 35 ~ 45min, converter tapping temperature is 1660 ~ 1700 ℃, temperature composition meets the requirements for converter tapping operation; S3. The molten steel is immediately sent to LF for refining, and then electrochemical slag is alloyed. After alloying, it is sent to RH for vacuum treatment. The high vacuum degree is maintained for 20 to 30 minutes, and vacuum fine stirring is performed for 10 to 20 minutes. After the temperature meets the requirements, it is sent to continuous casting for pouring. S4, use argon protection for the entire pouring process, pouring speed 0.6 ~ 1.3m / min, pouring superheat 10 ~ 20 ℃, use water spray cooling zone to ensure uniform and stable cooling; S5. After the billet passes the surface inspection, it is sent to the heating furnace for heating at a temperature of 1180-1260°C. A two-stage rolling process is adopted, with a second rolling temperature of 800-900°C, a final rolling temperature of 770-830°C, a water entry temperature of 750-800°C, and a return to redness of 400-600°C. S6. The cooled steel plates are stacked, sheared, marked and stored.

5. The method for producing steel for hydrogen pipeline according to claim 4, characterized in that: The thickness of the produced steel plates is 5 to 50 mm.

6. The method for producing steel for hydrogen pipeline according to claim 4, characterized in that: The product steel grade is X60M~X70M, and its performance meets API standard requirements.

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