High-temperature bolt steel BG25Cr2MoVA and preparation method thereof

Abstract

The invention discloses high-temperature bolt steel BG25Cr2MoVA and a preparation method thereof. The high-temperature bolt steel BG25Cr2MoVA comprises the following components of, by weight, 0.23-0.27% of C, 0.20-0.35% of Si, 0.54-0.62% of Mn, 0-0.015% of P, 0-0.012% of S, 1.64-1.72% of Cr, 0.28-0.32% of Mo, 0.20-0.24% of V, 0-0.15% of Ni, 0-0.15% of Cu, 0.020-0.040% of Alt, and the balance Fe and inevitable impurities. The high-temperature bolt steel BG25Cr2MoVA is high in steel purity degree, resistant to high temperature and fatigue, and stable in mechanical property. The preparation method is simple and practical, and the technology is stable.

Description

technical field

[0001] The invention relates to the technical field of steel preparation, and in particular provides a steel BG25Cr2MoVA for high-temperature bolts and a preparation method thereof. Background technique

[0002] The commissioning of large-capacity and high-parameter generating units has promoted the great development of China's power system. Therefore, the demand for steel for high-temperature bolts of turbines is also increasing. The quality of bolt steel is related to the operation stability of supercritical million-unit units. , the requirements for product quality are getting higher and higher. At present, steel for high-temperature bolts of turbines produced by various steel mills is mostly produced by die casting, with low yield, high cost, small output, slow production rhythm, and the use situation is not optimistic. The above question:

[0003] (1) The smelting rhythm of electric furnace continuous casting is fast, the ratio of molten iron is small, ...

Examples

Embodiment 1

[0030] Steel BG25Cr2MoVA for high temperature bolts, by weight percentage, includes the following components: C: 0.23%, Si: 0.35%, Mn: 0.54%, P≤0.015%, S≤0.012%, Cr: 1.72%, Mo: 0.28%, V: 0.20%, Ni≤0.15%, Cu≤0.15%, Alt: 0.040%, the balance is iron and unavoidable impurities.

[0031] The preparation method of steel BG25Cr2MoVA for this high temperature bolt is as follows:

[0032] Blast furnace molten iron undergoes pretreatment in turn→electric furnace smelting→refining furnace LF→vacuum degassing VD→medium billet continuous casting 235mm×265mm continuous casting slab→walking heating furnace heating→high pressure water descaling→rough rolling mill rolling→continuous rolling unit →slow cooling→annealing→finishing→flaw detection→inspection to obtain steel,

[0033] Among them, the electric furnace smelting adopts 50t electric furnace smelting, and the carbon reaches the target content requirement of 0.23%, and then the steel is deoxidized and alloyed;

[0034] The refining fur...

Embodiment 2

[0039] High temperature bolt steel BG25Cr2MoVA, by weight percentage, includes the following components: C: 0.27%, Si: 0.20%, Mn: 0.62%, P≤0.015%, S≤0.012%, Cr: 1.64%, Mo: 0.32%, V: 0.24%, Ni≤0.15%, Cu≤0.15%, Alt: 0.020%, the balance is iron and unavoidable impurities.

[0040] The preparation method of steel BG25Cr2MoVA for this high temperature bolt is as follows:

[0041] Blast furnace molten iron undergoes pretreatment in turn→electric furnace smelting→refining furnace LF→vacuum degassing VD→medium billet continuous casting 235mm×265mm continuous casting slab→walking heating furnace heating→high pressure water descaling→rough rolling mill rolling→continuous rolling unit →slow cooling→annealing→finishing→flaw detection→inspection to obtain steel,

[0042] Among them, the electric furnace smelting adopts 50t electric furnace smelting, and the carbon reaches the target content requirement of 0.27%, and then the steel is deoxidized and alloyed;

[0043] The refining furnace ...

Embodiment 3

[0048] High temperature bolt steel BG25Cr2MoVA, by weight percentage, includes the following components: C: 0.25%, Si: 0.25%, Mn: 0.58%, P≤0.012%, S≤0.010%, Cr: 1.68%, Mo: 0.30%, V: 0.22%, Ni≤0.10%, Cu≤0.10%, Alt: 0.030%, the balance is iron and unavoidable impurities.

[0049] The preparation method of steel BG25Cr2MoVA for this high temperature bolt is as follows:

[0050] Blast furnace molten iron undergoes pretreatment in turn→electric furnace smelting→refining furnace LF→vacuum degassing VD→medium billet continuous casting 235mm×265mm continuous casting slab→walking heating furnace heating→high pressure water descaling→rough rolling mill rolling→continuous rolling unit →slow cooling→annealing→finishing→flaw detection→inspection to obtain steel,

[0051] Among them, the electric furnace smelting adopts 50t electric furnace smelting, and the carbon reaches the target content requirement of 0.25%, and then the steel is deoxidized and alloyed;

[0052] The refining furnace ...

technical field

[0001] The invention relates to the technical field of steel preparation, and in particular provides a steel BG25Cr2MoVA for high-temperature bolts and a preparation method thereof. Background technique

[0002] The commissioning of large-capacity and high-parameter generating units has promoted the great development of China's power system. Therefore, the demand for steel for high-temperature bolts of turbines is also increasing. The quality of bolt steel is related to the operation stability of supercritical million-unit units. , the requirements for product quality are getting higher and higher. At present, steel for high-temperature bolts of turbines produced by various steel mills is mostly produced by die casting, with low yield, high cost, small output, slow production rhythm, and the use situation is not optimistic. The above question:

[0003] (1) The smelting rhythm of electric furnace continuous casting is fast, the ratio of molten iron is small, ...

Examples

Embodiment 1

[0030] Steel BG25Cr2MoVA for high temperature bolts, by weight percentage, includes the following components: C: 0.23%, Si: 0.35%, Mn: 0.54%, P≤0.015%, S≤0.012%, Cr: 1.72%, Mo: 0.28%, V: 0.20%, Ni≤0.15%, Cu≤0.15%, Alt: 0.040%, the balance is iron and unavoidable impurities.

[0031] The preparation method of steel BG25Cr2MoVA for this high temperature bolt is as follows:

[0032] Blast furnace molten iron undergoes pretreatment in turn→electric furnace smelting→refining furnace LF→vacuum degassing VD→medium billet continuous casting 235mm×265mm continuous casting slab→walking heating furnace heating→high pressure water descaling→rough rolling mill rolling→continuous rolling unit →slow cooling→annealing→finishing→flaw detection→inspection to obtain steel,

[0033] Among them, the electric furnace smelting adopts 50t electric furnace smelting, and the carbon reaches the target content requirement of 0.23%, and then the steel is deoxidized and alloyed;

[0034] The refining fur...

Embodiment 2

[0039] High temperature bolt steel BG25Cr2MoVA, by weight percentage, includes the following components: C: 0.27%, Si: 0.20%, Mn: 0.62%, P≤0.015%, S≤0.012%, Cr: 1.64%, Mo: 0.32%, V: 0.24%, Ni≤0.15%, Cu≤0.15%, Alt: 0.020%, the balance is iron and unavoidable impurities.

[0040] The preparation method of steel BG25Cr2MoVA for this high temperature bolt is as follows:

[0041] Blast furnace molten iron undergoes pretreatment in turn→electric furnace smelting→refining furnace LF→vacuum degassing VD→medium billet continuous casting 235mm×265mm continuous casting slab→walking heating furnace heating→high pressure water descaling→rough rolling mill rolling→continuous rolling unit →slow cooling→annealing→finishing→flaw detection→inspection to obtain steel,

[0042] Among them, the electric furnace smelting adopts 50t electric furnace smelting, and the carbon reaches the target content requirement of 0.27%, and then the steel is deoxidized and alloyed;

[0043] The refining furnace ...

Embodiment 3

[0048] High temperature bolt steel BG25Cr2MoVA, by weight percentage, includes the following components: C: 0.25%, Si: 0.25%, Mn: 0.58%, P≤0.012%, S≤0.010%, Cr: 1.68%, Mo: 0.30%, V: 0.22%, Ni≤0.10%, Cu≤0.10%, Alt: 0.030%, the balance is iron and unavoidable impurities.

[0049] The preparation method of steel BG25Cr2MoVA for this high temperature bolt is as follows:

[0050] Blast furnace molten iron undergoes pretreatment in turn→electric furnace smelting→refining furnace LF→vacuum degassing VD→medium billet continuous casting 235mm×265mm continuous casting slab→walking heating furnace heating→high pressure water descaling→rough rolling mill rolling→continuous rolling unit →slow cooling→annealing→finishing→flaw detection→inspection to obtain steel,

[0051] Among them, the electric furnace smelting adopts 50t electric furnace smelting, and the carbon reaches the target content requirement of 0.25%, and then the steel is deoxidized and alloyed;

[0052] The refining furnace ...