阅读说明：本技术 一种用于核电安全壳钢焊接的低合金钢焊条及其制备 (Low alloy steel welding rod for welding nuclear power containment steel and preparation thereof ) 是由 苏东东 公茂涛 刘鑫 张敏娟 吴宝鑫 林永祥 于 2019-09-18 设计创作，主要内容包括：本发明涉及一种用于核电安全壳钢焊接的低合金钢焊条及其制备,焊条由焊芯以及裹覆在焊芯表面的药皮组成,所述药皮由粉料组分与粘结剂混合而成,所述粉料组分包括以焊芯重量百分比计算的以下成分：大理石10～16％,萤石7～13％,电解锰1～4％,金红石1～4％,石英1～4％,硅铁1～3％,镍粉≤1％,钼铁≤1％,铁粉9～14％,石墨≤0.2％,纯碱0.1～0.5％,所述粘结剂为粉料组分总重量的15-25％。与现有技术相比,本发明制备的用于核电安全壳钢焊接的低合金钢焊条具备工艺性能优良、力学性能与母材匹配等优点,填补了该材料国内市场空白。(The invention relates to a low alloy steel welding rod for welding nuclear power containment steel and a preparation method thereof, wherein the welding rod consists of a core wire and a coating wrapped on the surface of the core wire, the coating is formed by mixing a powder component and a binder, and the powder component comprises the following components in percentage by weight of the core wire: 10-16% of marble, 7-13% of fluorite, 1-4% of electrolytic manganese, 1-4% of rutile, 1-4% of quartz, 1-3% of ferrosilicon, less than or equal to 1% of nickel powder, less than or equal to 1% of ferromolybdenum, 9-14% of iron powder, less than or equal to 0.2% of graphite, 0.1-0.5% of soda ash, and 15-25% of binder based on the total weight of the powder components. Compared with the prior art, the low alloy steel welding rod for welding the nuclear power containment steel, prepared by the invention, has the advantages of excellent technological properties, matching of mechanical properties with parent metal and the like, and fills the blank of the material in domestic market.)

1. The low alloy steel welding rod for welding nuclear power containment steel is characterized by comprising a core wire and a coating wrapped on the surface of the core wire, wherein the coating is formed by mixing a powder component and a binder, and the powder component comprises the following components in percentage by weight of the core wire: 10-16% of marble, 7-13% of fluorite, 1-4% of electrolytic manganese, 1-4% of rutile, 1-4% of quartz, 1-3% of ferrosilicon, less than or equal to 1% of nickel powder, less than or equal to 1% of ferromolybdenum, 9-14% of iron powder, less than or equal to 0.2% of graphite, 0.1-0.5% of soda ash, and 15-25% of binder based on the total weight of the powder components.

2. The low alloy steel welding rod for welding nuclear power containment steel according to claim 1, wherein the binder is water glass.

3. The low alloy steel welding rod for welding nuclear power containment steel according to claim 2, characterized in that the binder is sodium water glass, potassium water glass or potassium sodium water glass.

4. The low alloy steel electrode for nuclear power containment steel welding of claim 1, wherein the core wire comprises the following components in weight percent: less than or equal to 0.12 percent of C, 0.10-0.80 percent of Mn, less than or equal to 0.006 percent of (As + P), less than or equal to 0.008 percent of S, less than or equal to 0.10 percent of Si, and the balance of Fe.

5. The low alloy steel welding rod for nuclear power containment steel welding of claim 1, characterized in that CaCO in marble₃More than or equal to 97 wt%; in fluorite, CaF₂More than or equal to 95 wt%; in electrolytic manganese, Mn is more than or equal to 99.7 wt%; in rutile, TiO₂More than or equal to 95 wt%; in quartz, SiO₂More than or equal to 97 wt%; in the ferrosilicon, the Si content is 42-48 wt%; in the nickel powder, Ni is more than or equal to 99 wt%; in the ferromolybdenum, Mo is more than or equal to 55 wt%, C is less than or equal to 0.20 wt%, and Si is less than or equal to 2.0 wt%; in the iron powder, Fe is more than or equal to 98 wt%, C is less than or equal to 0.06 wt%, and Mn is less than or equal to 0.5 wt%; in the graphite, C is more than or equal to 97 wt%; na in soda ash₂CO₃≥99wt％。

6. The method for preparing a low alloy steel welding electrode for nuclear power containment steel welding according to any one of claims 1 to 5, characterized by comprising the following steps:

(1) uniformly mixing the powder components, adding a binder, and mixing to obtain a coating;

(2) and (3) coating the surface of the core wire with the coating prepared in the step (1), and baking to obtain the low alloy steel welding rod.

7. The method for preparing the low alloy steel welding rod for welding the nuclear power containment steel as claimed in claim 6, wherein the baking treatment process comprises two procedures of low-temperature baking and high-temperature baking.

8. The preparation method of the low alloy steel welding rod for welding the nuclear power containment steel according to claim 7, characterized in that the low-temperature baking is carried out at 80-120 ℃ for 1-3 h;

the high-temperature baking temperature is 220-350 ℃, and the time is 0.5-1.5 h.

Technical Field

The invention belongs to the technical field of welding materials, and relates to a low alloy steel welding rod for welding nuclear power containment steel and a preparation method thereof.

Background

A steel Containment Vessel (CV) is an important device in a passive safety system unique to an AP1000 nuclear power unit, a CAP1400 nuclear power unit and the like, and is an inner layer shielding structure of an AP1000 nuclear power station reactor factory building. The whole steel containment vessel consists of a cylindrical barrel in the middle and an upper elliptical seal head and a lower elliptical seal head (respectively called as a bottom seal head and an upper seal head). The maximum diameter of the steel containment vessel of the AP1000 nuclear power station is 39.624 meters, the total height is 65.633 meters, the thickness is 4.4 centimeters, the volume is about 7 ten-thousand cubic meters, and the total weight is about 3600 tons. The steel containment vessel is complex in stress, large in service temperature difference and long in design life, and the welding material for the containment vessel is required to have high strength and good impact toughness. In order to ensure the use safety of the containment, the westinghouse company selects a SA-738Gr.B steel plate as a base material for the AP1000 containment, and the welding materials recommended by the design are as follows: E9018-G welding rod, but the welding material in the equipment manufacturer is tested again and the welding rod of the mark can not meet the design requirement. At present, no electric welding rod for nuclear power containment vessel is disclosed in China.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a low alloy steel welding rod for welding nuclear power containment steel and a preparation method thereof.

The purpose of the invention can be realized by the following technical scheme:

one of the technical schemes of the invention is to provide a low alloy steel welding rod for welding nuclear power containment steel, which consists of a core wire and a coating wrapped on the surface of the core wire, wherein the coating is formed by mixing a powder component and a binder, and the powder component comprises the following components in percentage by weight of the core wire: 10-16% of marble, 7-13% of fluorite, 1-4% of electrolytic manganese, 1-4% of rutile, 1-4% of quartz, 1-3% of ferrosilicon, less than or equal to 1% of nickel powder, less than or equal to 1% of ferromolybdenum, 9-14% of iron powder, less than or equal to 0.2% of graphite, 0.1-0.5% of soda ash, and 15-25% of binder based on the total weight of the powder components.

Further, the binder is water glass.

Further, the binder is sodium water glass, potassium water glass or potassium sodium water glass.

Further, the core wire comprises the following components in percentage by weight: c is less than or equal to 0.12 percent, Mn is 0.10-0.80 percent, (As + P) (which means the total amount of As and P) is less than or equal to 0.006 percent, S is less than or equal to 0.008 percent, Si is less than or equal to 0.10 percent, and the balance is Fe.

Further, in marble, CaCO₃More than or equal to 97 wt%; in fluorite, CaF₂More than or equal to 95 wt%; in electrolytic manganese, Mn is more than or equal to 99.7 wt%; in rutile, TiO₂More than or equal to 95 wt%; in quartz, SiO₂More than or equal to 97 wt%; in the ferrosilicon, the Si content is 42-48 wt%; in the nickel powder, Ni is more than or equal to 99 wt%; in the ferromolybdenum, Mo is more than or equal to 55 wt%, C is less than or equal to 0.20 wt%, and Si is less than or equal to 2.0 wt%; in the iron powder, Fe is more than or equal to 98 wt%, C is less than or equal to 0.06 wt%, and Mn is less than or equal to 0.5 wt%; in the graphite, C is more than or equal to 97 wt%; na in soda ash₂CO₃≥99wt％。

The second technical scheme of the invention is to provide a preparation method of a low alloy steel welding rod for welding nuclear power containment steel, which comprises the following steps:

(1) uniformly mixing the powder components, adding a binder, and mixing to obtain a coating;

(2) and (3) coating the surface of the core wire with the coating prepared in the step (1), and baking to obtain the low alloy steel welding rod.

Further, the baking treatment process comprises two procedures of low-temperature baking and high-temperature baking.

Further, the low-temperature baking temperature is 80-120 ℃, and the time is 1-3 h;

the high-temperature baking temperature is 220-350 ℃, and the time is 0.5-1.5 h.

The main functions of the components in the coating are as follows:

and (3) marble: the method is mainly used for slagging and gas making, and welding seams are protected from being oxidized and nitrided by air; the melting point, viscosity, surface tension and interfacial tension of the slag can be adjusted.

Fluorite: the surface tension of the liquid metal and the melting point of the slag can be reduced, the fluidity of the slag can be improved, the weld joint is attractive in appearance, the pore sensitivity of the weld joint is reduced, and the diffusible hydrogen content of the deposited metal can be reduced. The proper proportion of marble and fluorite is the key, and the stability of electric arc, the covering of slag and the slagging are better when the proportion is proper.

Electrolytic manganese: manganese element is mainly transited to the welding seam, so that the strength of the welding seam is improved; secondly, the desulfurization and deoxidation functions are realized.

Rutile: the main functions are arc stabilization and slag forming, low-melting-point short slag is formed, the melting point, viscosity, surface tension and fluidity of the slag can be adjusted, the weld forming is improved, and splashing is reduced.

Quartz: mainly improves the fluidity of slag and improves the processing property of the welding rod.

Silicon iron: mainly plays a role in deoxidation.

Nickel powder: mainly plays a role in improving the impact toughness of the weld metal.

Ferromolybdenum: mainly improves the strength of the welding seam at room temperature and high temperature.

Iron powder: mainly plays a role in improving the technological performance of the welding rod.

Graphite: mainly improves the technological property of the welding rod.

Soda ash: the main function of the welding rod is to increase the smoothness and improve the press coating property of the welding rod, and the excessive addition amount is unfavorable for the press coating of the welding rod, so the addition amount is controlled.

Water glass: mainly as a binder, the water glass is beneficial to the stability of electric arc and is suitable for the press coating of the formula.

Core wire: H08E is adopted to control the content of impurities, wherein S is less than or equal to 0.008 wt% and (As + P) is less than or equal to 0.006 wt%. The lower impurity content is beneficial to improving the impact toughness of the deposited metal.

Compared with the prior art, the low-alloy welding rod prepared by the invention has excellent technological properties, matched mechanical properties with parent metal, meets the requirements of AWS A5.5E 9018-G, and is suitable for welding steel containment vessels in passive safety system nuclear power units such as AP1000, CAP1400 and the like.

Detailed Description

The present invention will be described in detail with reference to specific examples. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.