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Method for preparing low-carbon stainless steel

A technology of stainless steel and molten steel, applied in the field of manufacturing low-carbon stainless steel, can solve the problems of poor decarburization conditions and low decarburization efficiency, and achieve the effect of complete decarburization and high decarburization efficiency

Active Publication Date: 2013-08-21
SHANXI TAIGANG STAINLESS STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, to reduce the carbon content in steel, the goal must be achieved by increasing the temperature of molten steel in the early stage and reducing Pco by vacuuming. However, VOD only decarburizes on the surface of the molten steel, and the molten steel at the bottom of the ladle needs to overcome the static pressure of the molten steel, so the conditions for decarburization are poor; from the comparison of dynamic conditions, VOD is more restricted than RH, and VOD is affected by the bottom of the ladle. Blowing flow rate, ladle space and slag volume in the upper part of molten steel are greatly affected, so the decarburization efficiency is low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0065] Ⅰ Pretreatment of hot metal

[0066] 73 tons of molten iron of the mass percentage of following composition are carried out pretreatment:

[0067] S 0.038%; P 0.087%; Si 0.36%; the rest is Fe and unavoidable impurities. The temperature of molten iron is 1320°C.

[0068] After the molten iron is pretreated by removing S, P and Si, the mass percentage of the composition of the molten iron meets the following requirements:

[0069] S 0.022%; P 0.005%; Si 0.03%; the rest is Fe and unavoidable impurities, and the temperature of molten iron after pretreatment is 1290°C.

[0070] Ⅱ K-OBM-S converter smelting

[0071] The pretreated molten iron is added to the K-OBM-S converter for smelting, and the converter is bottom-blown with N 2 Gas operation, adding lime to each ton of molten iron—100kg / t, lightly burned magnesium balls—25kg / t, coke—18kg / t, high-carbon ferrochrome (69.2% chromium)-25 kg / t, high-carbon ferromanganese ( 7.5% carbon, 76% manganese)-3.5 kg / t...

Embodiment 2

[0102] Ⅰ Pretreatment of hot metal

[0103] 75 tons of molten iron of the mass percentage of following composition is carried out pretreatment:

[0104] S 0.028%; P 0.073%; Si 0.034%;

[0105] The rest is Fe and unavoidable impurities, and the temperature of molten iron is 1290°C.

[0106] After the molten iron is pretreated by removing S, P and Si, the mass percentage of the composition of the molten iron meets the following requirements:

[0107] S 0.015%; P 0.004%; Si 0.025%; the rest is Fe and unavoidable impurities, and the temperature of molten iron after pretreatment is 1270°C.

[0108] Ⅱ K-OBM-S converter smelting

[0109] The pretreated molten iron is added to the K-OBM-S converter for smelting, and the converter is bottom-blown with N 2 gas operation,

[0110] Add lime to each ton of molten iron—100kg / t, lightly burned magnesium balls—25kg / t, coke—18kg / t, high-carbon ferrochromium (69.2% chromium)-25 kg / t, high-carbon ferromanganese (carbon 7.5 %,...

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Abstract

The invention relates to a method for preparing low-carbon stainless steel, which sequentially comprises the following steps of 1, pretreatment of molten iron; 2, K-OBM-S converter smelting; 3, primary LF ladle refining; and 4, molten steel circulating vacuum decarburization: a, a common steel hot tank is used in an RH workbench, b, a bottom argon tube blowing tube begins to vacuumize, c, the vacuum pressure is lowered and oxygen blowing is carried out for decarburization, and the decarburization value is 0.025-0.035%, d, when oxygen blowing is over, the vacuum value is lowered to 40mbar, e, the carbon content reaches the target value of 0.025-0.035%, and restoring operation is carried out at the RH workbench, and f, after fine tuning, wherein the molten steel comprises the following components by mass percent: 0.020-0.030 of C, 0.52-0.58 of Si, 2.40-2.80 of Mn, P less than or equal to 0.030, less than or equal to 0.015 of S, 16.00-16.40 of Cr, 6.00-6.20 of Ni, 2.05-2.25 of Cu, and the balance of Fe and inevitable impurities, and then the molten steel is output, and the temperature of the molten steel is 1540-1550 DEG C. The method for preparing low-carbon stainless steel has high decarburization efficiency, and the content of carbon in the finished product can be 0.03% after decarburization.

Description

[0001] technical field [0002] The invention relates to a method for manufacturing low-carbon stainless steel. [0003] Background technique [0004] Carbon is the most important alloying element in traditional martensitic stainless steel. The reasonable ratio of chromium and carbon in steel has produced three types of Fe-Cr-C martensitic stainless steel with high, medium and low carbon. The role of carbon is to expand the γ zone and improve the hardenability of steel. However, with the increase of carbon content in steel and the strength and hardness of martensitic stainless steel, the plasticity, toughness, corrosion resistance, cold formability and weldability of steel will decrease. The role of carbon in stainless steel, in addition to the important impact on martensitic stainless steel, for austenitic stainless steel, ferritic stainless steel and duplex stainless steel, it is generally believed that its disadvantages outweigh its advantages. [0005] Carbon can incr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/58C22C33/06
Inventor 张霞李建民赵大同李道明侯东涛
Owner SHANXI TAIGANG STAINLESS STEEL CO LTD
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