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CN-121976115-A - Hot rolling production method of low-cost pure hydrogen conveying pipeline steel L360MH

CN121976115ACN 121976115 ACN121976115 ACN 121976115ACN-121976115-A

Abstract

The invention discloses a hot rolling production method of low-cost pure hydrogen conveying pipeline steel L360MH, which adopts a low-carbon equivalent design, remarkably improves weldability and hydrogen embrittlement resistance, forms a high-density nano-grade carbonitride precipitated phase by adding Ti/Nb composite microalloying refined grains, effectively acts as a hydrogen trap to inhibit hydrogen diffusion, strictly controls the contents of P (less than or equal to 0.013 percent) and S (less than or equal to 0.0015 percent) at the same time, reduces impurity segregation, reduces Hydrogen Induced Cracking (HIC) sensitivity, obtains fine and uniform ferrite+a small amount of pearlite structure (ferrite grain size is more than or equal to 9 grade) through a controlled rolling and cooling (TMCP) process, endows steel with excellent low-temperature toughness (-10 ℃ impact power is more than or equal to 200J) and high hydrogen embrittlement resistance by high-proportion small-angle grain boundaries and uniform precipitated phase inhibition crack propagation, ensures structural uniformity, and meets the mechanical requirements of pure hydrogen conveying.

Inventors

  • TIAN YUHAI
  • ZHOU MENGCHENG
  • KANG XU
  • SU CHENG
  • CAO YAN
  • DONG LEI
  • WANG SHAOBING
  • YUAN XIAOMING
  • HAN JUN
  • WEI HUIHUI
  • ZHANG XINFANG

Assignees

  • 内蒙古包钢钢联股份有限公司

Dates

Publication Date
20260505
Application Date
20260318

Claims (7)

  1. 1. A hot rolling production method of low-cost pure hydrogen conveying pipeline steel L360MH is characterized by comprising the following steps: (1) The alloy component is designed to be low-carbon and niobium-titanium, and the Ti/Nb composite microalloying refined crystal grain is met, so that the standard requirement of performance is met; (2) The phosphorus content of the molten iron is required to be less than or equal to 0.130 percent, the sulfur content is less than or equal to 0.050 percent, the silicon content is between 0.20 percent and 0.60 percent, and the temperature of the molten iron is more than or equal to 1350 ℃; (3) Tapping at the end point of the converter, wherein the tapping temperature of the converter is not less than 1620 ℃, and the tapping temperature of the converter is not less than 1600 ℃ to ensure that the ingredients and the temperature coordinate tapping; (4) Slagging and desulfurizing in an LF furnace, and adding aluminum iron, silicon iron, ferromanganese and ferroniobium alloy to adjust to a target component range; (5) The RH procedure is controlled according to the treatment mode, the vacuum degree is required to be less than or equal to 2.6mbar, the vacuum time is kept to be more than or equal to 20min, the RH vacuum treatment period is ensured to be more than or equal to 10min, ferrotitanium alloy is added to adjust components to a target range during the RH vacuum treatment period, the calcium treatment is carried out after the RH vacuum treatment is finished, and the soft blowing time is ensured to be more than or equal to 15min after the calcium treatment; (6) The casting machine adopts constant pulling speed control, and the pulling speed range is 1.0-1.5m/min; (7) The heating temperature of a heating furnace in the rolling process is 1170-1200 ℃, the cold charging time is 170-280min, the soaking temperature is 1160-1190 ℃ and the cold charging soaking time is 30-60min; (8) The initial rolling temperature of the finish rolling in the rolling process is 980-1050 ℃, and the final rolling temperature of the finish rolling is 830+/-15 ℃; (9) The cooling temperature in the rolling process is 560+/-20 ℃; The low-cost pure hydrogen conveying pipeline steel L360MH comprises the chemical components of ：C 0.04-0.06%,Si 0.10-0.15%,Mn 0.90-1.00%,P≤0.013%,S≤0.0015%,Alt 0.025-0.045%,Nb 0.025-0.035%,Ti 0.005-0.015%, by mass percent and the balance of Fe and impurities.
  2. 2. The method for hot rolling of low cost pure hydrogen transportation pipeline steel L360MH according to claim 1, wherein P, S content and gas control are P≤0.013%, S≤0.0015%, O≤0.0020%, N≤0.0050% and H≤0.0002%.
  3. 3. The hot rolling production method of the low-cost pure hydrogen transportation pipeline steel L360MH according to claim 1, wherein A, B, C, D inclusions are respectively less than or equal to 1.5 grades, and Ds inclusions are respectively less than or equal to 2.0 grades.
  4. 4. The hot rolling production method of the low-cost pure hydrogen transportation pipeline steel L360MH according to claim 1, wherein fine and uniform ferrite and a small amount of pearlite structure are obtained, and the grain size is more than or equal to 9 grades.
  5. 5. The hot rolling production method of the low-cost pure hydrogen transportation pipeline steel L360MH according to claim 1, wherein the low-cost pure hydrogen transportation pipeline steel L360MH comprises the following chemical components in percentage by mass of ：C 0.05%,Si 0.10%,Mn 1.00%,P 0.008%,S 0.0008%,Alt 0.036%,Nb 0.029%,Ti 0.011%,O 19ppm,N 35ppm,H 0.7ppm, and the balance of Fe and impurities.
  6. 6. The hot rolling production method of the low-cost pure hydrogen conveying pipeline steel L360MH, according to claim 5, characterized in that the hydrogen pressure and the nitrogen pressure are 6.3MPa, the pure hydrogen and pure nitrogen test boxes have volumes of more than or equal to 4000mL, the slow stretching rate is 5X 10 -6 /s, the test result is that the reduction of area loss value of a base metal in a hydrogen environment is 26.9% and the reduction of area loss value of a weld joint is 32.9% compared with that of the base metal in a nitrogen environment.
  7. 7. The hot rolling production method of the low-cost pure hydrogen conveying pipeline steel L360MH, which is characterized in that the average K value of the base metal fracture toughness in a hydrogen environment is 110.7 MPa.m 1/2 , the average K value of the weld joint fracture toughness is 88.2 MPa.m 1/2 , the average K value of the heat affected zone fracture toughness is 93.8 MPa.m 1/2 , and all the requirements of GB/T46599-2025 are met and are not less than 55 MPa.m 1/2 .

Description

Hot rolling production method of low-cost pure hydrogen conveying pipeline steel L360MH Technical Field The invention belongs to the technical field of metallurgy, and particularly relates to a hot rolling production method of low-cost pure hydrogen conveying pipeline steel L360 MH. Background The inner Mongolia autonomous region has abundant wind and light resources, the hydrogen production potential of renewable energy sources is larger, the hydrogen transmission pipeline is a key link for the coordinated development of the large-scale development and the absorption of the linked hydrogen energy, and is an important connection network of green hydrogen infrastructure and related line stations, storage peak shaving facilities and connection and disconnection facilities. The powerful construction of the green hydrogen pipeline has important significance for promoting the high-quality development of the green hydrogen industry of the autonomous region, and the boosting autonomous region is used for constructing a clean, low-carbon, safe and efficient modern energy system. The hydrogen energy industry is vigorously developed. The hydrogen production scale is leading nationwide, ten thousand tons of photovoltaic hydrogen production projects are built nationwide, hydrogen energy infrastructures are gradually perfected, green hydrogen traffic and green hydrogen to green ammonia application scenes play an exemplary leading role nationwide, hydrogen metallurgy and locomotive test demonstration are carried out, and green hydrogen coupling coal chemical industry and green hydrogen to green methanol application scenes are continuously built. The hydrogen delivery pipeline is tested first. The Ulan inspection cloth-Yanshan petrochemical hydrogen transmission pipeline demonstration project is incorporated into the oil gas 'one net nationwide', and is the first hydrogen transmission pipeline crossing province areas, large scale and long distance in China. And on day 11 and 22, the inner Mongolia seal issues 'the development planning of the green hydrogen pipeline construction of the inner Mongolia autonomous region'. It is pointed out that the total mileage of hydrogen pipelines on a global scale has exceeded 6000 km, with the operating hydrogen pipelines in the united states having reached 2600 km. In contrast, the total mileage of the existing hydrogen transmission pipeline in China is about 400 km, the pipeline is only about hundred km, the upstream and downstream large-scale development of the green hydrogen industry chain cannot be supported, and a large-scale long-distance hydrogen transmission pipeline needs to be constructed. The current construction reaches the pure hydrogen pipeline transportation engineering from the maoqi to the Baotou, the transportation mileage is about 200 km, the design transportation pressure is 6.3MPa, the pipeline specification D457 multiplied by 12mm, and the current brand L360MH has accumulated to be more than 1.8 ten thousand tons. Through retrieval, the document with the Chinese patent application number of CN 118756036A discloses 360MPa grade pipeline steel for a low-proportion hydrogen-doped conveying pipeline and a preparation method thereof, and the method is applicable to C：0.03～0.06％、Si：0.10～0.30％、Mn：0.90～1.15％ 、Nb：0.020～0.050％ 、Ti：0.010～0.030％ 、Als：0.020～0.040％ 、P≤0 .010％ 、S≤0 .0015％ 、H≤2ppm、O≤30ppm、N≤50ppm, , wherein the balance of Fe and unavoidable impurities, the mechanical properties of the steel are 400-500 MPa of yield strength, 500-600 MPa of tensile strength and 35-45% of elongation A50. The literature is mainly characterized by the conventional mechanical properties and hydrogen compatibility of low-proportion hydrogen-doped L360M grade pipeline steel, and the patent is mainly aimed at low-grade pure hydrogen conveying pipeline steel L360MH, so as to prepare coiled plates meeting the requirements of hydrogen energy development. Through searching, the document with the Chinese patent application number of CN 119876785A discloses a high-grade hydrogen transmission pipeline steel and a preparation method thereof, the method is suitable for C：0.02～0.04％、Si：0.20～0.30％、Mn：1.20～1.30％、P≤0.010％,S≤0.0010％,Alt：0.015～0.055％,N：≤0.0020％,O：≤0.0010％,H：≤0.0001％,Cr：0.90～1.00％,Mo：0.40～0.50％,Ti：0.020～0.030％,Nb：0.05～0.07％,Ni≤0.40～0.50％,, the balance of Fe and unavoidable impurities, CSR=0, CLR=0 and CTR=0 under A solution, slow stretching IRA and IEL are less than or equal to 20 percent, and under a pure hydrogen environment of 6.3 MPa, the step-type compact tensile sample KIH is more than or equal to 100 MPa.m1/2, and the fatigue life is more than or equal to 50 ten thousand times. The disadvantage of this document is that although the overall properties are excellent and the hydrogen compatibility properties are good, the relative manufacturing cost increases, which is unfavorable for long-term development. Through searching, the document of Chinese patent application No. CN 1179876