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Nb-Ti microalloying steel suitable for large line energy welding and smelting method therefor

A technology of high-energy welding and micro-alloyed steel, applied in welding medium, welding equipment, welding equipment, etc., can solve the problems of reducing the toughness of the base metal, weakening the effect of pinning grain boundaries, difficult to control production, etc., to achieve the production process. Simple, wide range of ingredients, good toughness

Inactive Publication Date: 2007-05-16
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, pure Ti microalloying is not suitable for large input energy
In addition, the traditional TiN technology does not require desulfurization treatment, and TiN is easy to form composite particles with sulfide, which weakens the effect of pinning grain boundaries.
This is another disadvantage of the technique
[0005] Reducing the toughness of the base metal, not adapting to the requirements of large input energy and difficult to control in production are the main shortcomings of the existing technology

Method used

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  • Nb-Ti microalloying steel suitable for large line energy welding and smelting method therefor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Example 1, according to the composition requirements of the steel of the present invention, two furnaces of container steel were smelted. According to the requirements of Rel ≥ 490MPa container steel, the composition is selected as low C, high Mn series, and Mo, V, Ni alloys are added at the same time. The smelting process is LD+LF+VD, LF treatment is 20 minutes, VD treatment is 15 minutes, and the composition of VD is fine-tuned, adding Ti iron and Nb iron. This is followed by two-stage controlled rolling and accelerated cooling. Rolled into 24mm steel plate, 60KJ / cm, 90KJ / cm, 120KJ / cm welding tests were carried out. In addition, traditional steel plates produced by the same rolling process with different chemical components were subjected to welding tests of the same system, so as to compare the adaptability of the steel produced by the present invention and the traditional steel plate to high heat input welding. The data are shown in Tables 1-3.

[0029] Table 1, ...

Embodiment 2

[0036]Example 2, two furnaces of atmospheric corrosion resistant steel were smelted, and the components all met the requirements of the present invention. The components are low C, high Si and low Mn series, and more Cr, Ni and Cu elements are added according to the requirements of corrosion resistance, and the contents are all within the scope of the present invention. The first furnace adopts the smelting process of the present invention, that is, LD+LF+RH, LF slagging and S removal, refining for 18 minutes, RH treatment for 25 minutes, adjusting the composition, and adding Ti and Nb in RH. The second furnace adopts LD+RH, without desulfurization process, RH treatment for 25 minutes, including adjustment of alloy elements such as Ti and Nb are all carried out in RH. After smelting, use ordinary hot rolling method to roll into 10mm steel plate, conduct welding tests of 50KJ / cm and 70KJ / cm, and compare the performance of welding heat affected zone of the two steel plates. See...

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Abstract

The invention discloses an Nb-Ti microalloy steel for large line power welding, which comprises the following parts: 0.06%-0.12% C, 0.10%-0.50% Si, 0.40%-1.8% Mn, not more than 0.015% P, not more than 0.010% S, 0.020%-0.050% Nb, 0.006%-0.030% Ti, 0.0030%- 0.0100% N, one or more of not more than 0.40% Mo, not more than 0.06% V, not more than 1.0% Ni, not more than 1.0% Cr, and not more than 0.50% Cu and Fe and inevitable impurity, wherein the Ceq is C+Mn / 6+Si / 24+Ni / 40+Cr / 5+Mo / 4+V / 14<=0.45%; the [Ti%]T is not less than 2.667[N%]T-0.004667%. The smelting method comprises the following steps: predisposing molten iron; smelting through rotary furnace; removing S in the LF furnace; refining in the VD or RH; adding Ti and Nb in the VD or RH. The steel board possesses excellent flexibility in the welding heat influencing region when it is welded at 50-150KJ / cm.

Description

technical field [0001] The invention relates to a Nb-Ti micro-alloy steel which can be welded with large heat input and a smelting method thereof, belonging to the field of low-alloy steel manufacturing. Background technique [0002] During the welding process of the steel plate, due to the action of the welding heat cycle, the microstructure and properties of the welding heat-affected zone will change, especially the low-temperature toughness will be greatly reduced. When the welding line energy reaches 50-150KJ / cm, the toughness is generally less than half of the base metal. [0003] Before the present invention, there have been some public reports of steels for large heat input. For example, the patent applied by Kawasaki Iron and Steel Co., Ltd. "Steel for welding with high heat input of more than 500KJ / cm and its manufacturing method" (application number 96105716.8) and the patent declared by Wuhan Iron and Steel Company "Large input energy welding non-quenched and tem...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/14C22C33/04B23K31/12B23K35/22C21C7/04B22D11/115
Inventor 郝森付魁军李震吕东苏国阳及玉梅王东明翟晓丽
Owner ANGANG STEEL CO LTD
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