阅读说明：本技术 一种与高Mn、高Nb抗裂纹缺陷的镍基焊带配套使用的焊剂及焊接方法 (Welding flux matched with nickel-based welding strip with high Mn content and high Nb content and capable of preventing crack defects and welding method ) 是由 徐锴 冯伟 邹力维 曹宇堃 胡晓波 张庆素 魏涛 韩宇 刘满雨 陈绍维 吉荣亮 于 2019-10-08 设计创作，主要内容包括：一种与高Mn、高Nb抗裂纹缺陷的镍基焊带配套使用的焊剂及焊接方法,本发明一种与高Mn、高Nb抗裂纹缺陷的镍基焊带配套使用的焊剂及焊接方法。本发明的目的是为了提供一种与高Mn、高Nb抗裂纹缺陷的镍基焊带配套使用的焊剂及焊接方法。本发明焊剂是由CaF<Sub>2</Sub>、SiO<Sub>2</Sub>、Al<Sub>2</Sub>O<Sub>3</Sub>、CaO、MgO、Cr<Sub>2</Sub>O<Sub>3</Sub>、铁合金或NaF、S和P组成。焊接的方法为：焊接电流950-1100A,焊接电压28V,焊接速度180mm/min,堆焊层厚度30mm。本发明攻克了同类产品裂纹敏感性高的问题,提出了高Mn、高Nb新型合金成分,解决了工程应用大厚度热裂纹问题。本发明应用于核电焊接领域。(The invention discloses a welding flux and a welding method matched with a nickel-based welding strip with high Mn and high Nb crack resistance defects. The invention aims to provide a welding flux matched with a nickel-based welding strip with high Mn and Nb cracking resistance and a welding method. The flux of the invention is made of CaF 2 、SiO 2 、Al 2 O 3 、CaO、MgO、Cr 2 O 3 Iron alloy or NaF, S and P. The welding method comprises the following steps: the welding current is 950-1100A, the welding voltage is 28V, the welding speed is 180mm/min, and the thickness of the overlaying layer is 30 mm. The invention solves the problem of high crack sensitivity of similar products, provides novel alloy components with high Mn and high Nb, and solves the problem of large-thickness thermal cracking in engineering application. The invention is applied to the field of nuclear power welding.)

1. The flux is matched with a nickel-based welding strip with high Mn content and high Nb content and crack resistance, and is characterized in that the flux consists of 25-50 parts of CaF (calcium fluoride) by mass₂5-20 parts of SiO₂10-40 parts of Al₂O₃8-20 parts of CaO, 4-15 parts of MgO and Cr₂O₃Not more than 5 parts, not more than 8 parts of ferroalloy, not more than 0.015 part of S and not more than 0.02 part of P.

2. The flux according to claim 1, wherein the flux comprises 38-45 parts by weight of CaF₂7-14 parts of SiO₂12-35 parts of Al₂O₃11-18 parts of CaO, 4-12 parts of MgO and 1-4 parts of Cr₂O₃Less than or equal to 8 parts of ferroalloy, less than or equal to 0.015 part of S and less than or equal to 0.02 part of P.

3. The welding flux used in combination with the high-Mn high-Nb anti-crack defect nickel-based welding strip as claimed in claim 1, wherein the high-Mn high-Nb anti-crack defect nickel-based welding strip comprises, by weight, C less than or equal to 0.04%, Si less than or equal to 0.50%, Mn less than or equal to 5.0%, S less than or equal to 0.015%, P less than or equal to 0.020%, Cr: 28.0-31.5%, Fe: 7.0 to 12.0 percent of Nb, less than or equal to 2.5 percent of Nb, less than or equal to 0.30 percent of Cu, less than or equal to 0.50 percent of Al, less than or equal to 0.50 percent of Ti, less than or equal to 0.05 percent of Mo, less than or equal to 0.02 percent of Co and the balance of nickel.

4. The flux is matched with a nickel-based welding strip with high Mn content and high Nb content and crack resistance, and is characterized in that the flux consists of 25-50 parts of CaF (calcium fluoride) by mass₂5-20 parts of SiO₂10-40 parts of Al₂O₃8-20 parts of CaO, 4-15 parts of MgO and Cr₂O₃Not more than 5 parts, not more than 5 parts of NaF, not more than 0.015 part of S and not more than 0.02 part of P.

5. The flux according to claim 3, wherein the flux comprises 38-45 parts by weight of CaF₂7-14 parts of SiO₂12-35 parts of Al₂O₃11-18 parts of CaO, 4-12 parts of MgO and 1-4 parts of Cr₂O₃NaF is less than or equal to 5 parts, S is less than or equal to 0.015 part and P is less than or equal to 0.02 part.

6. The welding flux used in combination with the high-Mn high-Nb anti-crack defect nickel-based welding strip as claimed in claim 3, wherein the high-Mn high-Nb anti-crack defect nickel-based welding strip comprises, by weight, C less than or equal to 0.04%, Si less than or equal to 0.50%, Mn less than or equal to 5.0%, S less than or equal to 0.015%, P less than or equal to 0.020%, Cr: 28.0-31.5%, Fe: 7.0 to 12.0 percent of Nb, less than or equal to 2.5 percent of Nb, less than or equal to 0.30 percent of Cu, less than or equal to 0.50 percent of Al, less than or equal to 0.50 percent of Ti, less than or equal to 0.05 percent of Mo, less than or equal to 0.02 percent of Co and the balance of nickel.

7. The method for welding by utilizing the nickel-based welding strip with high Mn and high Nb crack defects and the matched welding flux is characterized in that the nickel-based welding strip with high Mn and high Nb crack defects and the matched welding flux are subjected to surfacing by adopting a strip submerged arc surfacing technology to obtain surfacing metal; wherein the submerged arc welding process parameters are as follows: the welding current is 950-1100A, the welding voltage is 28V, the welding speed is 180mm/min, and the thickness of the overlaying layer is 30 mm.

8. The method for welding by using the nickel-based welding strip with high Mn and high Nb content and the matched flux according to claim 7, which is characterized in that the surfacing metals comprise the following components in parts by weight: less than or equal to 0.30 portion of C, less than or equal to 0.30 portion of Si, 3.5 to 5.0 portions of Mn, less than or equal to 0.003 portion of S, less than or equal to 0.005 portion of P, 28.5 to 31.0 portions of Cr, 7.0 to 8.0 portions of Fe, 1.5 to 2.5 portions of Nb, less than or equal to 0.30 portion of Cu, less than or equal to 0.20 portion of Al, less than or equal to 0.10 portion of Ti, less than or equal to 0.05 portion of Mo, less than or equal to 0.02 portion of Co, and less than or equal to 0.358 portion of.

Technical Field

The invention relates to a welding flux matched with a nickel-based welding strip with high Mn content and high Nb content and a welding method.

Background

Along with the development of nuclear power industry, the surface of one side of a tube plate of a steam generator of a pressurized water reactor nuclear power station needs large-area surfacing of nickel-based alloy, wherein a strip surfacing material is the most common method, the surfacing efficiency is high, and the welding mode comprises the following steps: strip electroslag surfacing and submerged arc surfacing, but the submerged arc type welding flux has wide application. According to the requirements of nuclear power technology and corrosion medium, materials of the welding strip are gradually developed from INCONEL 600 to INCONEL 690, the surfacing materials of the steam generator tube plate in the third-generation nuclear power technology are all made of INCONEL 690 materials, the INCONEL 690 is subjected to EQNiCrFe-7A, the EQNiCrFe-7A is used more, but problems such as DDC cracks and the like are not solved, the welding strip is developed to EQNiCrFe-14 at present, but crack sensitivity is larger, the problem of large-thickness surfacing crack sensitivity is solved by adding alloy elements such as Mn and Nb with crack defects through system test research, corresponding submerged arc type welding flux is not developed or is not mature at present, and the development of novel welding flux becomes more important and can meet the actual needs of engineering.

Disclosure of Invention

The invention aims to provide a welding flux matched with a nickel-based welding strip with high Mn and Nb cracking resistance and a welding method.

The flux matched with the nickel-based solder strip with high Mn content and high Nb content and capable of resisting crack defects is prepared from 25-50 parts by mass of CaF₂5-20 parts of SiO₂10-40 parts of Al₂O₃8-20 parts of CaO, 4-15 parts of MgO and Cr₂O₃Not more than 5 parts, not more than 8 parts of ferroalloy, not more than 0.015 part of S and not more than 0.02 part of P.

The flux matched with the nickel-based solder strip with high Mn content and high Nb content and capable of resisting crack defects is prepared from 25-50 parts by mass of CaF₂5-20 parts of SiO₂10-40 parts of Al₂O₃8-20 parts of CaO, 4-15 parts of MgO and Cr₂O₃Not more than 5 parts, not more than 5 parts of NaF, not more than 0.015 part of S and not more than 0.02 part of P.

The method for welding by using the nickel-based welding strip with high Mn and high Nb crack defects and the matched welding flux comprises the following steps: carrying out surfacing by using a nickel-based welding strip with high Mn and high Nb and anti-crack defects and a matched welding flux by adopting a strip submerged arc surfacing technology to obtain surfacing metal; wherein the submerged arc welding process parameters are as follows: the welding current is 950-1100A, the welding voltage is 28V, the welding speed is 180mm/min, and the thickness of the overlaying layer is 30 mm.

The invention provides a novel submerged arc type sintered flux matched with a welding strip, which has reasonable component design, can ensure the crack sensitivity of a surfacing layer and has wider welding process parameters. Effective impurity element control, reasonable alkalinity design, solving the problem that the multilayer welding process performance is easy to have slag sticking and undercut phenomena.

CaF₂: the main functions are slagging, desulfurizing and dehydrogenating. Because of the higher viscosity of the nickel-based alloy, the spreading property of the surfacing metal is generally required to be increased, the tendency of undercut and the like is reduced, and CaF₂Too low, weldingThe slag removal performance of the agent is reduced, the viscosity of slag is increased, the forming is poor, and the undercut phenomenon occurs in the lapping process, so that the amount is desirably high, but the forming of surfacing metal is reduced too much, the arc form is not obvious, and simultaneously excessive impurity elements are brought in, so that the nickel-based crack sensitivity is increased.

SiO₂: the main functions are slag removal and improvement of technological properties, but when the content is excessive, the oxidability is enhanced, the burning loss of the alloy elements of the surfacing layer is increased, the mechanical property and the corrosion property of surfacing metal are reduced, and meanwhile, excessive SiO is used₂It will also lead to increased silicon content in the weld metal and increased crack sensitivity of the weld metal, for which SiO is the cause₂The content is preferably controlled to 5-15%.

Al₂O₃The main function is slag removal, the slag belongs to neutral oxide, the weld bead forming can be improved, when the content is too low, the melting point and viscosity of the slag are low, the coverage is poor, the corrugation of the weld bead is thick, when the content is too high, the melting point of the slag is increased, the high-temperature retention time of the weld bead is short, the spreading performance is poor, the undercut phenomenon of the weld bead is easy to occur, and the corrugation is thick.

CaO: the main effect is slagging, the effect of adjustment basicity, the effect of stable electric arc prevents to splash and has certain benefit, and CaO has the effect of taking off S simultaneously, can improve the purity of nickel base build-up welding metal, but the too high welding seam shaping that can influence of content, and the slagging difficulty.

MgO: the method mainly comprises slagging and improving the alkalinity of molten slag, but MgO has higher melting point and is added too high, the solidification temperature of the molten slag is increased too much, the fluidity of the slag is inhibited, and when the addition amount exceeds 15 percent, the welding bead forming becomes poor and the slag removal is difficult.

Cr₂O₃The method improves the weld forming and has certain benefits for slag removal.

NaF: the wettability of the surfacing metal is increased, and undercut is prevented.

Alloying agent (iron alloy): the main functions are deoxidation and alloy burning loss supplement, and a certain amount of alloy is added to reduce the nickel base crack sensitivity and improve the mechanical property of the metal.

The invention summarizes the nickel-based alloy welding which is mature at presentOn the basis of the welding material, the influence of each alloy element on the mechanical property, the corrosion resistance and the crack resistance of the nickel-based alloy welding material is comprehensively considered, and the alloy components are optimized, so that the performance of the nickel-based alloy welding material is guaranteed to reach the standard, the nickel-based alloy has higher welding hot crack sensitivity in the welding process, cracks are easy to generate in an arc pit, an intercrystalline liquid film is the most main metallurgical factor for initiating the solidification cracks of a single-phase structure of the nickel-based alloy, the internal components are uneven or a molten pool is not clean, C, S, P, Si and other elements form low-melting-point eutectic crystals in the molten pool, the impurity segregation phenomenon is serious in the crystallization process, and in order to prevent the generation of the welding hot cracks, the contents of S, P and other impurities are required to be. First, flux impurity elements C, SiO are tightly controlled₂S, P content. Powder and alloy with low content of S, P and other impurity elements are selected as raw materials for preparing the welding flux, and the content of alloying elements such as Nb, Ti, Mn, Mo and the like is adjusted to reduce the sensitivity of deposited metal crystal cracks and DDC. The flux developed for the purpose needs to ensure various mechanical properties and crack sensitivity of the surfacing metal and have good welding process performance, particularly multilayer welding process performance, the viscosity of a nickel-based material is high, and slag adhesion is easy to occur in the process of welding multilayer welding.

The nickel-based submerged arc surfacing flux disclosed by the invention is matched with a novel nickel-based high-Mn high-Nb welding strip, is suitable for surfacing of important structural components such as a reactor pressure vessel, a steam generator tube plate surfacing and the like, has excellent deslagging performance, better weld bead spreading performance, no undercut phenomenon, no slag adhesion during multilayer welding and easiness in deslagging, and solves key indexes such as crystal cracks, DDC cracks and the like of a nickel-based material surfacing layer. The welding flux has low impurity content, reduces harmful impurities brought by raw materials as much as possible, reduces S, P content in the welding flux, and ensures the purity of weld metal. The addition of CaO and ferroalloy further increases the S, P removal effect of the weld deposit metal. The optimal component proportion is found through controlling Mn and Nb alloy elements of the welding strip, the problem of high crack sensitivity of similar products is solved, the technical index of the content of S + Si is provided, the problem of large-thickness hot cracks in engineering application is solved, and other performance indexes are qualified.

Detailed Description