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Treating agent and method for controlling primary carbide of high-carbon martensitic stainless steel through melt treatment

A technology of carbon martensite and treatment agent, which is applied in the field of carbide control of high-carbon martensitic stainless steel, and can solve the problems of inconspicuous aggregation and growth of carbides, inclusions, and unsuitability for clean production.

Active Publication Date: 2021-05-14
ZHONGBEI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The existing research results show that electroslag remelting and refining can significantly purify molten steel, reduce inclusions, and inhibit the heterogeneous nucleation of carbides to a certain extent, but the effect of inhibiting the aggregation and growth of carbides is not obvious
The rheological modification method is generally used in the production of cast iron and cast steel. This method may be able to improve the morphology of carbides, but at the same time precipitate a large number of inclusions, which is not suitable for clean production

Method used

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  • Treating agent and method for controlling primary carbide of high-carbon martensitic stainless steel through melt treatment
  • Treating agent and method for controlling primary carbide of high-carbon martensitic stainless steel through melt treatment
  • Treating agent and method for controlling primary carbide of high-carbon martensitic stainless steel through melt treatment

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Select 7Cr14 martensitic stainless steel (composition: C: 0.65% to 0.75%, Cr: 13.5 to 15.5%, Mn: 0.45 to 0.65%, Si: 0.25 to 0.45%, Mo: 0.35 to 0.45%, V: Mo: 0.35 ~0.45%), according to the method for controlling carbide of the present invention, implement the primary carbide of controlling 7Cr14 martensitic stainless steel, mainly comprise the following steps:

[0026] Using a 200kg intermediate frequency furnace to smelt 200kg molten steel in the atmosphere, taking into account the burning loss of alloy elements, the composition is controlled within the upper limit of the allowable range;

[0027] After completely melting and holding for 5 minutes, refine in the furnace. The weight percentage of each component of the refining slag system is: 30% CaO, 40% SiO 2 , 25%Al 2 o 3 , 5% MgO and other components.

[0028] After refining for 20 minutes, feed the wire and add a melt treatment agent. The composition of the melt treatment agent is: 40% rare earth ferrosilicon, 30...

Embodiment 2

[0032] Select 7Cr14 martensitic stainless steel (composition: C: 0.65% to 0.75%, Cr: 13.5 to 15.5%, Mn: 0.45 to 0.65%, Si: 0.25 to 0.45%, Mo: 0.35 to 0.45%, V: Mo: 0.35 ~0.45%), according to the method for controlling carbide of the present invention, implement the primary carbide of controlling 7Cr14 martensitic stainless steel, mainly comprise the following steps:

[0033] Using a 200kg intermediate frequency furnace to smelt 200kg molten steel in the atmosphere, taking into account the burning loss of alloy elements, the composition is controlled within the upper limit of the allowable range;

[0034] After completely melting and holding for 5 minutes, refine in the furnace. The weight percentage of each component of the refining slag system is: 10% CaO, 50% SiO 2, 25%Al 2 o 3 , 15% MgO and other components.

[0035] After refining for 20 minutes, feed the wire and add a melt treatment agent. The composition of the melt treatment agent is: 70% rare earth ferrosilicon, 20...

Embodiment 3

[0038] Select 7Cr14 martensitic stainless steel (composition: C: 0.65% to 0.75%, Cr: 13.5 to 15.5%, Mn: 0.45 to 0.65%, Si: 0.25 to 0.45%, Mo: 0.35 to 0.45%, V: Mo: 0.35 ~0.45%), according to the method for controlling carbide of the present invention, implement the primary carbide of controlling 7Cr14 martensitic stainless steel, mainly comprise the following steps:

[0039] Using a 200kg intermediate frequency furnace to smelt 200kg molten steel in the atmosphere, taking into account the burning loss of alloy elements, the composition is controlled within the upper limit of the allowable range;

[0040] After completely melting and holding for 5 minutes, refine in the furnace. The weight percentage of each component of the refining slag system is: 60% CaO, 15% SiO 2 , 10% Al 2 o 3 , 15% MgO and other components.

[0041] After refining for 20 minutes, feed the wire and add a melt treatment agent. The composition of the melt treatment agent is: 20% rare earth ferrosilicon, ...

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Abstract

The invention discloses a method for improving an as-cast structure of a high-carbon martensitic stainless steel casting blank through melt treatment so as to control primary carbides. The control method comprises the following steps of induction furnace or converter and electric furnace, LF refining, RH refining, wire feeding and adding of a proper amount of melt treating agent, and blank casting; LF refining is selectively carried out according to the refining process requirement of the steel grade, and if not, the next step is directly carried out; RH refining is selectively carried out according to the refining process requirements of steel types, and if not, the next step is directly carried out; after selective LF refining or RH refining, a proper amount of melt treating agent is added through wire feeding; and the casting blank is produced by adopting a corresponding casting method and normal process parameters according to the steel grade and the production process requirement. The method for improving the as-cast structure of the high-carbon martensitic stainless steel casting blank through the melt treatment can effectively refine the primary carbide of high-carbon martensitic stainless steel and improve the composition segregation of the casting blank at the same time, and a structure and composition basis are provided for further refining the carbide through plastic deformation and effectively strengthening the secondary carbide through tempering.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting, in particular to a high-carbon martensitic stainless steel carbide control technology, which improves the as-cast structure of a slab through melt treatment and achieves the purpose of refining the primary as-cast carbides. Background technique [0002] Martensitic stainless steel can change the properties of the material through heat treatment, and has huge market demand in the fields of aviation industry, heavy transportation, nuclear power, medical treatment, and knives. In order to meet the requirements of high strength and high corrosion resistance, high carbon and high chromium is an important development direction of martensitic stainless steel (carbon content not less than 0.4wt%). High-carbon martensitic stainless steel contains more than 10% Cr and a small amount of carbide-forming elements such as Mo, V, W, and Nb. The purpose is to precipitate fine secondary carbides a...

Claims

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Application Information

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IPC IPC(8): C21C7/00C21C7/076C21C7/10
CPCC21C7/0006C21C7/0056C21C7/076C21C7/10C21C2007/0018Y02P10/20
Inventor 闫志杰樊玮荟陈永安李大赵王睿康燕苗芳
Owner ZHONGBEI UNIV
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