Method for smelting large energy input welded pipeline steel

A technology of large heat input welding and smelting methods, applied in the field of pipeline steel smelting, can solve the problems of smelting process details and deoxidation alloying control methods that have not been reported publicly, complex smelting and deoxidation alloying processes, etc., to reduce production costs , Improve the quality pass rate, improve the effect of strength and toughness

Inactive Publication Date: 2010-05-12
WUHAN UNIV OF SCI & TECH
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  • Summary
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AI Technical Summary

Problems solved by technology

The main factor restricting the application of oxide metallurgy technology is its complex smelting and deoxidation alloying process. Although there are high-g

Method used

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Examples

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Embodiment 1

[0013] A method for smelting pipeline steel welded with large heat input: Weak deoxidation with barium-silicon alloy, ferrosilicon alloy and ferromanganese alloy in the process of tapping the converter-LF furnace white slag-RH vacuum carbon deoxidation-LF refining deep desulfurization-titanium Alloying iron and boron-iron-calcium treatment of molten steel-low superheat casting, that is, pipeline steel slabs welded with large input energy. In the smelting process of this embodiment: control the acid-soluble aluminum content in molten steel at 0.0015% to 0.0020% during weak deoxidation; control the dissolved oxygen content in molten steel at 0.0015% to 0.0020% during RH vacuum carbon deoxidation; Medium titanium / aluminum mass ratio ≥10.

[0014] The main chemical components of the pipeline steel obtained by the method described in this example are: w(C) 0.04%~0.06%, w(S)≤0.003%, w(P)≤0.003%, w(Si)0.2%~ 0.4%, w(Mn)1.8%~2.0%, w(N)≤0.005%, w(B)0.001%~0.0015%, w(Ti)0.020%~0.025%, w...

Embodiment 2

[0016] A method of smelting pipeline steel welded with large heat input: Weak deoxidation with silicon-barium alloy, silicon-manganese alloy and ferromanganese alloy in the process of tapping the converter-LF furnace white slag-RH vacuum carbon deoxidation-LF refining deep desulfurization-titanium Alloying iron and boron-iron-calcium treatment of molten steel-low superheat casting, that is, pipeline steel slabs welded with large input energy. In the smelting process of this embodiment: control the acid-soluble aluminum content in molten steel at 0.0010% to 0.0015% during weak deoxidation; control the dissolved oxygen content in molten steel at 0.0020% to 0.0030% during RH vacuum carbon deoxidation; Medium titanium / aluminum mass ratio ≥10.

[0017] The main chemical components of the pipeline steel obtained by the method are: w(C)0.04%~0.06%, w(S)≤0.003%, w(P)≤0.003%, w(Si)0.2%~0.4%, w(Mn)1.8%~2.0%, w(N)≤0.005%, w(B)0.001%~0.0015%, w(Ti)0.015%~0.020%, w(O)0.0020%~0.0030%, w( ...

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Abstract

The invention relates to a method for smelting large energy input welded pipeline steel. The technical scheme thereof comprises the following steps: in the process of tapping from a converter, using more than two of silicon barium alloy, manganese silicon alloy, ferro-manganese alloy and ferro-silicon alloy to carry out the procedures of weak deoxidation, LF white slag generation in the converter, RH vacuum carbon deoxidation, LF refining deep desulphurization, ferrotitanium and ferroboron alloying, steel liquid calcium processing and low degree of superheat casting. When the procedure of the weak deoxidation, the content of acid-dissolved-aluminum is less than 0.0020 percent in the steel liquid; the content of dissolved oxygen is 0.0015-0.030 percent in the steel liquid during the procedure of the RH vacuum carbon deoxidation; before casting, the mass ratio of titanium to aluminum is greater than and equal to 10. The invention uses a deoxidation alloying process of the vacuum carbon deoxidation and an added ferrotitanium final deoxidation, strictly controls the content of the aluminum, the titanium and the oxygen in the steel liquid, so that Ti2O3 impurities with 0.2-2 microns can be fully separated out in the steel liquid during the process of solidifying, the oxides doped in the pipeline steel welding heat-affected zone can induce acicular ferrite so as to achieve the purposes of refining the components of the welding heat-affected zone and improving the strength and the toughness of the welding heat-affected zone.

Description

technical field [0001] The invention relates to the technical field of pipeline steel production. In particular, the invention relates to a method for smelting pipeline steel welded by large heat input. Background technique [0002] Due to the local remelting of the weld metal during steel welding, the grains near the fusion line will be coarsened to form a coarse-grained heat-affected zone (CGHAZ) during the post-weld cooling process, and the coarse-grained structure will lead to a decrease in local strength and toughness (Tian Zhiling. TMCP Research on Fracture Toughness of Steel Local Brittle Zone [J]. Iron and Steel Research Journal, 1998, 10(4): 50~53). Therefore, the heat-affected zone (HAZ) of welding becomes the weak area of ​​steel components. In recent years, as high-grade pipeline steels such as X100~X120 are welded by single-sided submerged arc welding, gas-electric welding or electroslag welding, which greatly improves welding efficiency, the welding line ener...

Claims

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Application Information

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IPC IPC(8): C22C33/04C21C5/28C21C7/076C21C7/10C21C7/068C21C7/064C21C7/06
CPCY02P10/20
Inventor 薛正良齐江华
Owner WUHAN UNIV OF SCI & TECH
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