Smelting process for improving near-surface flaw detection defects of shaft rudder system steel

A near-surface, shaft-rudder system technology, applied in the field of steel, can solve problems such as restricting the development of shaft-rudder systems and ship parts, and achieve the effects of improving the qualified rate of flaw detection, reducing the scrap rate and improving economic benefits.

Inactive Publication Date: 2020-01-10
石钢京诚装备技术有限公司
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Problems solved by technology

Therefore, the defects of near-surface flaw detection have restricted th

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  • Smelting process for improving near-surface flaw detection defects of shaft rudder system steel
  • Smelting process for improving near-surface flaw detection defects of shaft rudder system steel
  • Smelting process for improving near-surface flaw detection defects of shaft rudder system steel

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[0038] A smelting process for improving near-surface flaw detection defects of shaft and rudder steel, comprising the following steps:

[0039] 1) Converter tapping carbon ≥ 0.06%, tapping phosphorus ≤ 0.012%; converter tapping temperature 1610-1660°C.

[0040] Add steel core aluminum 150-280 kg during the tapping process; add lime 600-800 kg; add pre-melted slag 300-500 kg; feed aluminum wire 150-200 meters after tapping.

[0041] 2) SiC deoxidation for refining, 400-600 kg; refining white slag time: 43-60 minutes;

[0042] 3) Holding time under high vacuum: 25-30 minutes. During the vacuum holding period, it is necessary to observe that the molten steel surface is obviously exposed to ensure the vacuum degassing effect.

[0043] 4) After the VD is broken, feed 250-300 meters of manganese nitride wire; feed 40-80 meters of calcium wire. VD soft blowing time: 25-30 minutes;

[0044] 5) When pouring molten steel, the superheat of the hanging bag: 105-120°C; add 100-200 kg of...

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Abstract

The invention relates to a smelting process for improving near-surface flaw detection defects of shaft rudder system steel. The smelting process comprises the following steps of: (1) tapping by a converter; (2) refining; (3) high vacuumizing; (4) feeding wires after VD is broken; (5) pouring molten steel; (6) baking a draft tube; (7) pouring molten steel in a tundish; (8) pouring molten steel; (9)baking a steel ingot heat insulation cap opening; (10) pouring tundish molten steel; and (11) ending pouring of the tundish. By improving the smelting and pouring processes, the near-surface flaw detection defects of forgings such as marine propeller shafts, intermediate shafts and rudders are reduced, the near-surface flaw detection percent of pass is greatly improved, the rejection rate is reduced, and the economic benefit is remarkably improved.

Description

technical field [0001] The invention relates to the technical field of iron and steel, in particular to a smelting process for improving near-surface flaw detection defects of shaft and rudder steel. Background technique [0002] With the development of the shipbuilding industry and the intensification of competition, the internal quality requirements of large forgings such as marine propeller shafts and intermediate shafts are becoming increasingly stringent. Products that could meet the requirements before have become difficult to meet the needs of customers with the development of the times. At the same time, due to the shaft and rudder forgings, they are made of carbon-manganese series steel. This type of steel is prone to segregation and often becomes a weak point, resulting in failure of flaw detection. [0003] For a long time, the production of carbon-manganese steel forgings for shaft and rudder system adopts converter primary refining, ladle refining and vacuum d...

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Application Information

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IPC IPC(8): C21C7/06C21C7/10C21C7/00C21C7/064
CPCC21C7/0006C21C7/005C21C7/0056C21C7/06C21C7/0645C21C7/10
Inventor 张玉亭刘宪民
Owner 石钢京诚装备技术有限公司
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