Low-silicon aluminum-containing steel and production method thereof

Abstract

The invention relates to a production method of low-silicon aluminum-containing steel. The method is characterized in that: in converter terminal-point molten steel, the content of C is no lower than 0.05at%, the content of P is no lower than 0.020at%, and a tapping temperature is 1630-1670 DEG C. High-carbon ferromanganese and aluminum-manganese-titanium deoxidizing agents are added, and a refining target is that [Al]=0.060-0.080at%. In the LF refining furnace, component fine tuning is carried out, wherein addition amounts of medium-carbon ferromanganese and aluminum wires are determined according to alloy elements of the converter molten steel. Wire feeding treatment is carried out by using Ca-Fe wires, wherein a requirement on molten steel before calcium treatment is that [Al]=0.045-0.060at%. The Ca-Fe wires are vertically fed, wherein a feeding speed is no lower than 2.1m / s, and a [Ca] / [Al] mass ratio is 0.08-0.12. During continuous casting production, a superheat degree is controlled at 25-35 DEG C, and a casting speed is controlled within a range of 2.2-2.6m / min. When casting is started, 10 Ca-Fe wires are added in a middle-ladle T-port. When a large ladle begins casting, 3-5 Ca-Fe wires are added into the middle-ladle at the 1 and 6 flow stoppers. The method provided by the invention is advantaged in that: under a premise that a technical route is not changed, outlet flocculation blocking during continuous casting of the steel is avoided with a specific technology, and a control target of low silicon content is satisfied.

Description

technical field [0001] The invention relates to a production method of low-silicon and aluminum-containing steel, which belongs to the field of metallurgy and metal materials. Background technique [0002] SWRCH22A is a low-silicon and aluminum-containing cold heading steel. The wire rod produced by this steel is a common raw material for the production of screws and nuts in the fastener manufacturing industry. Its chemical composition is shown in Table 1. [0003] Table 1 chemical composition (mass percentage) [0004] [0005] At present, when most domestic steel mills produce SWRCH22A, they adopt the process route of converter smelting-LF ladle furnace refining-billet continuous casting. However, during continuous casting, nodules often occur at nozzles and flocculate dead nozzles, which makes it impossible to realize continuous casting production. Affected the smooth production of this steel type, some steel mills have given up the production of this steel type affec...

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Problems solved by technology

[0005] At present, when most domestic steel mills produce SWRCH22A, they adopt the process route of converter smelting-LF ladle furnace refining-billet continuous casting. However, during continuous casting, nodules often occur at nozzles and flocculate dead nozzles, which makes it impossible to realize continuous casting production. It has affected the smooth production of this steel type, and some steel mills have given up the production of this steel type due to its influence

[0006] The reason is that SWRCH22A is a low-silicon and aluminum-containing cold heading steel, which requires Al in the steel 全 ≥0.025% (mass percentage), due to the strong reduction of Al, so a large amount of it is Al 2 o 3 The form exists in steel, a large amount of Al 2 o 3 The existence of the presence of the billet continuous casting machine caused the flocculation of the nozzle

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