Smelting method to improve the purity of TDS2205 duplex stainless steel

A technology of TDS2205 and duplex stainless steel, which is applied in the field of stainless steel manufacturing, can solve the problems of unfavorable corrosion resistance of finished products, affecting the thermal processing and service performance of TDS2205 duplex stainless steel, unfavorable thermal processing of billets, etc., and achieve the goal of improving the purity of steel Effect

Active Publication Date: 2017-09-01
SHANXI TAIGANG STAINLESS STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] TDS2205 duplex stainless steel requires that the C content in the steel is ≤0.03%. When using AOD to produce this variety, the conventional method uses FeSi to reduce Cr, Ni, Mo and other metals and remove oxygen in the steel. However, due to the limited deoxidation ability of Si, the oxygen content of the finished product As high as 30ppm ~ 50ppm, which is not conducive to the thermal processing of the billet in the later stage, and is not conducive to ensuring better corrosion resistance of the finished product
Even if low-aluminum FeSi with low aluminum content is used as a deoxidizer, since it contains 0.5% to 1.5% Al, when the oxygen content is high, Al will be generated in the steel 2 o 3 Inclusions also affect the thermal processing and performance of TDS2205 duplex stainless steel

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] This embodiment provides a smelting method for improving the purity of TDS2205 duplex stainless steel. The process flow is: "Electric Furnace-AOD-LF-Continuous Casting", which specifically includes the following contents:

[0029] 1. The electric furnace uses stainless steel scrap (77.4%), ferrochrome (19.2%), and nickel plate (3.4%) as raw materials. The tapping composition of the electric furnace is: C: 1.95%, Si: 0.11%, Mn: 0.13%, P: 0.019%, S: 0.026%, Cr: 23.62%, Ni: 3.82%, N: 0.0132%.

[0030] 2. AOD is smelted by conventional methods. During the reduction period, low-aluminum FeSi is used to reduce the metal in the slag. The composition of AOD tapping is: C: 0.0225%, Si: 0.577%, Mn: 1.12%, P: 0.018%, S: 0.0029%, Cr: 22.60%, Ni: 5.59%, Mo: 3.18%, N: 0.1670%. The tapping temperature is 1660°C, and the tapping volume is 193 tons.

[0031] 3. After AOD taps the slag, the thickness of the slag layer is 140mm.

[0032] 4. Add 560kg of CaO and 406kg of CaF after the l...

Embodiment 2

[0039] This embodiment provides a smelting method for improving the purity of TDS2205 duplex stainless steel. The process flow is: "electric furnace-AOD-LF-continuous casting", which specifically includes the following content: in the semi-hot charging process, the weight ratio is: 40%-60% of molten iron, 20%-40% of ferrochrome, 10%-30% of scrap steel;

[0040] 1. The electric furnace uses converter dephosphorized hot metal (54.7%), ferrochromium (33.4%), and scrap steel (11.9%) as raw materials. The steel composition of the electric furnace is: C: 2.57%, Si: 0.17%, Mn: 0.08%, P : 0.017%, S: 0.017%, Cr: 21.11%, Ni: 3.82%, N: 0.31%.

[0041] 2. AOD is smelted by conventional methods. During the reduction period, low-aluminum FeSi is used to reduce the metal in the slag. The composition of AOD tapping is: C: 0.0215%, Si: 0.501%, Mn: 1.17%, P: 0.016%, S: 0.0059%, Cr: 22.62%, Ni: 5.54%, Mo: 3.14%, N 0.1580%. The tapping temperature is 1648°C, and the tapping volume is 192 tons. ...

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Abstract

The invention discloses a smelting process for improving purity of TDS2205 duplex stainless steel. The method comprises the following operations: slagging off after AOD (argon oxygen decarburization) tapping, wherein a slag layer is 70-200 mm in thickness; adding CaO after a ladle enters an LF station to ensure LF slag binary basicity is > / =4; adding CaF2 accounting for 0.2%-0.025% of weight of molten steel; after an LF is electrified to melt slag, adding 0.1%-0.2% of aluminum powder and 0.010%-0.025% of aluminum blocks to slag surface; after adjusting molten steel temperature to a suitable valve dependent on the rhythm of production, feeding a Ca line of 0.5-0.7 kg / t steel into the steel; then slightly stirring under 50-150 NL / min flow for 20 min; after slight stirring, standing for 20 min before casting, wherein the whole casting process is under protection. The use of the process enables oxygen content in the molten steel to be controlled to 10 ppm to 15 ppm, type B inclusions in the steel are of grade < / =0.5, and the purity of the steel is evidently improved.

Description

Technical field [0001] The invention relates to a smelting method for improving the purity of TDS2205 duplex stainless steel, and belongs to the field of stainless steel manufacturing. Background technique [0002] TDS2205 has high strength (its yield strength is generally twice that of austenitic stainless steel) due to its high Cr, Mo and N content, and the coexistence of austenite and ferrite in the room temperature structure at a ratio of about 1:1. , good resistance to Cl-pitting corrosion, stress corrosion resistance and welding performance and other outstanding advantages, it is widely used in petrochemical, salt production, hydraulic engineering, shipbuilding, civil and other fields. Compared with ordinary austenitic stainless steel and super austenitic stainless steel, the Ni content in the steel is significantly reduced, and the manufacturing cost is reduced. It is a high-performance, resource-saving steel type. Compared with ordinary 2205 duplex stainless steel, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C7/06
CPCC21C7/0006C21C7/06
Inventor 李亮李国平裴明德
Owner SHANXI TAIGANG STAINLESS STEEL CO LTD
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