A kind of q345r steel plate with excellent performance under high temperature simulated post-weld heat treatment conditions and its manufacturing method

Abstract

The invention relates to a Q345R steel plate with excellent performance under high-temperature simulated post-weld heat treatment conditions. The steel plate comprises 0.16-0.20% of C, 0.25-0.45% of Si, 1.40-1.60% of Mn, 0-0.008% of P, 0-0.002% of S, 0.02-0.05% of Al, 0.02-0.05% of Nb, 0.01-0.05% of Ti, 0.10-0.30% of Ni, 0.10-0.30% of Cu and balance Fe and inevitable impurity elements, wherein thecarbon equivalent ceq is less than or equal to 0.45%. A large compression ratio design is adopted, and the main working procedures comprise smelting, two-stage rolling and normalizing heat treatment.The steel plate is in a normalizing delivery state, the delivery state surface Brinell hardness is less than or equal to 170 HB, the transverse impact energy on the 1 / 2 thickness portion of the steelplate obtained after high-temperature simulated post-weld heat treatment at -30 DEG C is larger than or equal to 100 J, the yield strength is larger than or equal to 325 Mpa, the tensile strength islarger than or equal to 500 Mpa, the elongation percentage after fracture A is larger than or equal to 25.0%, and the flaw detection of the steel plate can meet the requirements of I-grade NB / T47013.3standards.

Description

technical field

[0001] The invention belongs to the field of steel plate manufacturing, and in particular relates to a Q345R steel plate for boilers and pressure vessels with a thickness of 20-100 mm and excellent performance under high-temperature simulated post-weld heat treatment conditions and a manufacturing method thereof. Background technique

[0002] Q345R is the largest and most widely used steel plate for boilers and pressure vessels in my country. With the rapid development of economic construction and petrochemical industry manufacturing, the demand for Q345R steel plates in the market is increasing. The requirements for heat treatment performance are getting higher and higher, and the simulated post-weld heat treatment insulation temperature is increased from 580-635°C to 650°C. In recent years, since the same container equipment is designed to use two materials of Q345R and hydrogen chromium molybdenum steel at the same time, after the equipment is manufactured,...

Examples

Embodiment 1

[0041] The thickness of the steel plate in this embodiment is 20mm, and its chemical composition is calculated by weight percentage: its chemical composition is calculated by weight percentage: C: 0.165%, Si: 0.41%, Mn: 1.42%, P: 0.006%, S: 0.001 %, Al: 0.032%, Nb: 0.030%, Ti: 0.015%, Ni: 0.22%, Cu: 0.20%, the balance is Fe and unavoidable impurity elements, carbon equivalent Ceq: 0.435%, carbon equivalent calculation formula It is: Ceq=C+Mn / 6+(Cr+Mo+V) / 5+(Ni+Cu) / 15.

[0042] The manufacturing process of the steel plate is as follows:

[0043] The continuous casting slab with a section of 370mm is used as the blank, and the specific operation of the main process is as follows:

[0044] 1) Smelting process

[0045] Smelting raw materials are sequentially subjected to KR molten iron pretreatment, converter smelting, LF refining, RH vacuum degassing treatment and slab continuous casting process. Slagging treatment after converter smelting, calcium treatment after LF refining, ...

Embodiment 2

[0054] The thickness of the steel plate in this embodiment is 50mm, and its chemical composition is calculated by weight percentage: C: 0.16%, Si: 0.42%, Mn: 1.42%, P: 0.005%, S: 0.0008%, Al: 0.034%, Nb: 0.032%, Ti: 0.016%, Ni: 0.25%, Cu: 0.21%, the balance is Fe and unavoidable impurity elements, carbon equivalent Ceq: 0.44%, carbon equivalent calculation formula is: Ceq=C+Mn / 6 +(Cr+Mo+V) / 5+(Ni+Cu) / 15.

[0055] The manufacturing process of the steel plate is as follows:

[0056] The continuous casting slab with a section of 450mm is used as the blank, and the specific operation of the main process is as follows:

[0057] 1) Smelting process

[0058] Smelting raw materials are sequentially subjected to KR molten iron pretreatment, converter smelting, LF refining, RH vacuum degassing treatment and slab continuous casting process. Slagging treatment after converter smelting, calcium treatment after LF refining, RH vacuum treatment with a limit vacuum degree of 60Pa, a vacuum ...

Embodiment 3

[0067] The thickness of the steel plate in this embodiment is 100mm, and its chemical composition is calculated by weight percentage: C: 0.17%, Si: 0.45%, Mn: 1.45%, P: 0.005%, S: 0.0005%, Al: 0.035%, Nb: 0.035%, Ti: 0.014%, Ni: 0.23%, Cu: 0.22%, the balance is Fe and unavoidable impurity elements, carbon equivalent Ceq: 0.445%, carbon equivalent calculation formula is: Ceq=C+Mn / 6+ (Cr+Mo+V) / 5+(Ni+Cu) / 15.

[0068] The manufacturing process of the steel plate is as follows:

[0069] The continuous casting slab with a section of 450mm is used as the blank, and the specific operation of the main process is as follows:

[0070] 1) Smelting process

[0071] Smelting raw materials are sequentially subjected to KR molten iron pretreatment, converter smelting, LF refining, RH vacuum degassing treatment and slab continuous casting process. Slagging treatment after converter smelting, calcium treatment after LF refining, RH vacuum treatment with a limit vacuum degree of 60Pa, a vacuu...

technical field

[0001] The invention belongs to the field of steel plate manufacturing, and in particular relates to a Q345R steel plate for boilers and pressure vessels with a thickness of 20-100 mm and excellent performance under high-temperature simulated post-weld heat treatment conditions and a manufacturing method thereof. Background technique

[0002] Q345R is the largest and most widely used steel plate for boilers and pressure vessels in my country. With the rapid development of economic construction and petrochemical industry manufacturing, the demand for Q345R steel plates in the market is increasing. The requirements for heat treatment performance are getting higher and higher, and the simulated post-weld heat treatment insulation temperature is increased from 580-635°C to 650°C. In recent years, since the same container equipment is designed to use two materials of Q345R and hydrogen chromium molybdenum steel at the same time, after the equipment is manufactured,...

Examples

Embodiment 1

[0041] The thickness of the steel plate in this embodiment is 20mm, and its chemical composition is calculated by weight percentage: its chemical composition is calculated by weight percentage: C: 0.165%, Si: 0.41%, Mn: 1.42%, P: 0.006%, S: 0.001 %, Al: 0.032%, Nb: 0.030%, Ti: 0.015%, Ni: 0.22%, Cu: 0.20%, the balance is Fe and unavoidable impurity elements, carbon equivalent Ceq: 0.435%, carbon equivalent calculation formula It is: Ceq=C+Mn / 6+(Cr+Mo+V) / 5+(Ni+Cu) / 15.

[0042] The manufacturing process of the steel plate is as follows:

[0043] The continuous casting slab with a section of 370mm is used as the blank, and the specific operation of the main process is as follows:

[0044] 1) Smelting process

[0045] Smelting raw materials are sequentially subjected to KR molten iron pretreatment, converter smelting, LF refining, RH vacuum degassing treatment and slab continuous casting process. Slagging treatment after converter smelting, calcium treatment after LF refining, ...

Embodiment 2

[0054] The thickness of the steel plate in this embodiment is 50mm, and its chemical composition is calculated by weight percentage: C: 0.16%, Si: 0.42%, Mn: 1.42%, P: 0.005%, S: 0.0008%, Al: 0.034%, Nb: 0.032%, Ti: 0.016%, Ni: 0.25%, Cu: 0.21%, the balance is Fe and unavoidable impurity elements, carbon equivalent Ceq: 0.44%, carbon equivalent calculation formula is: Ceq=C+Mn / 6 +(Cr+Mo+V) / 5+(Ni+Cu) / 15.

[0055] The manufacturing process of the steel plate is as follows:

[0056] The continuous casting slab with a section of 450mm is used as the blank, and the specific operation of the main process is as follows:

[0057] 1) Smelting process

[0058] Smelting raw materials are sequentially subjected to KR molten iron pretreatment, converter smelting, LF refining, RH vacuum degassing treatment and slab continuous casting process. Slagging treatment after converter smelting, calcium treatment after LF refining, RH vacuum treatment with a limit vacuum degree of 60Pa, a vacuum ...

Embodiment 3

[0067] The thickness of the steel plate in this embodiment is 100mm, and its chemical composition is calculated by weight percentage: C: 0.17%, Si: 0.45%, Mn: 1.45%, P: 0.005%, S: 0.0005%, Al: 0.035%, Nb: 0.035%, Ti: 0.014%, Ni: 0.23%, Cu: 0.22%, the balance is Fe and unavoidable impurity elements, carbon equivalent Ceq: 0.445%, carbon equivalent calculation formula is: Ceq=C+Mn / 6+ (Cr+Mo+V) / 5+(Ni+Cu) / 15.

[0068] The manufacturing process of the steel plate is as follows:

[0069] The continuous casting slab with a section of 450mm is used as the blank, and the specific operation of the main process is as follows:

[0070] 1) Smelting process

[0071] Smelting raw materials are sequentially subjected to KR molten iron pretreatment, converter smelting, LF refining, RH vacuum degassing treatment and slab continuous casting process. Slagging treatment after converter smelting, calcium treatment after LF refining, RH vacuum treatment with a limit vacuum degree of 60Pa, a vacuu...

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