A kind of 500mpa level niobium-containing threaded steel bar and its manufacturing method

A technology of threaded steel bar and manufacturing method, which is applied to 500MPa grade niobium-containing threaded steel bar and its manufacturing field, can solve the problems of insufficient strengthening effect and high production difficulty, and achieves reducing the difficulty of production operation, reducing the addition of precious alloy elements, and saving alloy costs. Effect

Active Publication Date: 2020-02-07
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] Aiming at the deficiencies in the prior art, the present invention provides a 500MPa grade niobium-containing threaded steel bar and its manufacturing method, which solves the problems of insufficient strengthening effect of niobium in the current niobium-containing steel bar or the difficulty of production by controlled rolling and controlled cooling technology, and reduces the Under the conditions of alloy cost and simplified rolling process, microstructure refinement and strength improvement of niobium-containing rebar are realized

Method used

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  • A kind of 500mpa level niobium-containing threaded steel bar and its manufacturing method
  • A kind of 500mpa level niobium-containing threaded steel bar and its manufacturing method
  • A kind of 500mpa level niobium-containing threaded steel bar and its manufacturing method

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Effect test

Embodiment 1

[0049] A kind of 500MPa level niobium-containing threaded steel bar, its chemical composition and the mass fraction of each composition are shown in Table 1, the precipitates of the Nb-containing compound contained in it, and the RE-containing compound (in this embodiment, RE selects La) and / or See Table 2 for the number of inclusions containing Ti compounds.

[0050] A method for manufacturing 500MPa grade niobium-containing rebar, comprising the following steps:

[0051] Step 1, molten steel smelting

[0052] The molten iron is smelted into molten steel in a converter. When the tapping temperature is 1660°C, the mass fraction of carbon is 0.13%, the mass fraction of oxygen is 0.04%, the mass fraction of sulfur is 0.03%, and the mass fraction of phosphorus is 0.02%. Add silicon and manganese in the process of ~3 / 4, and adjust the content of C, Si, and Mn elements in molten steel after tapping to obtain molten steel;

[0053] Step 2: Inclusion Control

[0054] According to ...

Embodiment 2

[0065] A 500MPa level niobium-containing threaded steel bar, the chemical composition and the mass fraction of each composition are shown in Table 1, the precipitates of the Nb-containing compound contained in it, and the RE-containing compound (in this embodiment, RE selects Y) and / or See Table 2 for the number of inclusions containing Ti compounds.

[0066] A method for manufacturing 500MPa grade niobium-containing rebar, comprising the following steps:

[0067] Step 1, molten steel smelting

[0068] Melt molten iron and steel scrap (by mass ratio, molten iron:scrap = 5:1) into molten steel in a converter, tapping temperature 1670°C, carbon mass fraction 0.08%, oxygen mass fraction 0.06%, sulfur mass fraction 0.036% , when the mass fraction of phosphorus is 0.01%, silico-manganese is added in the process of tapping 1 / 3 to 3 / 4, and after tapping, the content of C, Si and Mn element components in molten steel is adjusted to obtain molten steel;

[0069] Step 2: Inclusion Con...

Embodiment 3

[0079] A kind of 500MPa level niobium-containing threaded steel bar, its chemical composition and the mass fraction of each composition are shown in Table 1, the precipitates of the Nb-containing compound contained in it, and the RE-containing compound (in this embodiment, RE selects Ce) and / or See Table 2 for the number of inclusions containing Ti compounds.

[0080] A method for manufacturing 500MPa grade niobium-containing rebar, comprising the following steps:

[0081] Step 1, molten steel smelting

[0082] Melt molten iron and steel scrap (by mass ratio, molten iron:scrap = 1:2) into molten steel in an electric furnace, tapping temperature 1640°C, carbon mass fraction 0.12%, oxygen mass fraction 0.05%, sulfur mass fraction 0.03% , when the mass fraction of phosphorus is 0.036%, silico-manganese is added in the process of tapping 1 / 3 to 3 / 4, and after tapping, the content of C, Si, and Mn element components in molten steel is adjusted to obtain molten steel;

[0083] Ste...

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Abstract

A 500 MPa niobium-containing ribbed reinforcing bar and a manufacturing method therefor, relating to the field of ribbed reinforcing bar production. The reinforcing bar comprises: C: 0.20-0.25%; Si: 0.5-0.8%; Mn: 1.2-1.6%; P: 0.01-0.04%; S: 0.01-0.04%; Ti: 0.005-0.02%; RE: 0.001-0.01%; Nb: 0.015-0.035%; O: 0.003-0.01%; N: 0.003-0.01%; and the balance of Fe and inevitable impurities. In the reinforcing bar, the number of precipitates containing a Nb compound and having an equivalent diameter of 0.003-0.03 μm is 50-500 / μm 2; the total number of inclusions containing a RE compound and / or a Ti compound and having an equivalent diameter of 0.03-3 μm is 2000-4000 / mm 2. The manufacturing method comprises: smelting, inclusion control, continuous casting, continuously cast billet heating, and reinforcing bar rolling. The method implements the low-cost and high-quality production of 500 MPa ribbed reinforcing bars.

Description

technical field [0001] The invention belongs to the technical field of threaded steel bar production, in particular to a 500MPa niobium-containing threaded bar and a manufacturing method thereof. Background technique [0002] Rebar is an important raw material in construction, transportation, engineering and other fields. It has the largest output and widest application in steel products. The promotion and application of high-strength steel bars can reduce the amount of steel used and optimize the design of building structures, which is of great significance for promoting energy saving and emission reduction and eliminating backward production capacity. At present, the application of hot-rolled threaded steel bars in my country is mainly 400MPa grade, and the amount of 500MPa grade steel bars is relatively small, which still needs to be further promoted and applied. For a long time, the production of high-strength steel bars has been dominated by vanadium microalloying tech...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/14C22C38/12C21D8/08
CPCC21D8/08C21D2211/005C21D2211/009C22C38/005C22C38/02C22C38/04C22C38/12C22C38/14Y02P10/20
Inventor 王超袁国康健李振垒王国栋
Owner NORTHEASTERN UNIV LIAONING
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