CN112404671A

CN112404671A - Solid welding wire for FCB (flux cored arc welding) method high heat input submerged arc welding and preparation method and application thereof

Info

Publication number: CN112404671A
Application number: CN202011229265.0A
Authority: CN
Inventors: 朱伏先; 李素坤; 朱雨; 庄焱磊
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-11-06
Filing date: 2020-11-06
Publication date: 2021-02-26
Anticipated expiration: 2040-11-06
Also published as: CN112404671B

Abstract

The invention discloses a solid welding wire for FCB (flux cored arc welding) method high heat input submerged arc welding and a preparation method and application thereof, belonging to the technical field of welding materials. The welding wire comprises the following chemical components (wt.%): 0.06-0.09% of C, 0.12-0.28% of Si, 1.52-2.0% of Mn, 0.0001-0.3% of A, and the balance of Fe and inevitable impurities; wherein: the element A is one or more of Mg, Ca, Zr, RE and B. The solid welding wire also comprises Ti, Ni and Cu (or Ti and V) in chemical components. The welding wire disclosed by the invention can ensure that a welding joint has the strength and the low-temperature impact toughness matched with those of a base metal after welding with the online energy of 60-300 kJ/cm. The welding wire is suitable for FCB method of structural steel plate with thickness less than 40mm and large heat input welding of other submerged arc welding machines.

Description

Solid welding wire for FCB (flux cored arc welding) method high heat input submerged arc welding and preparation method and application thereof

Technical Field

The invention relates to the technical field of welding materials, in particular to a solid welding wire for FCB (flux cored arc welding) high heat input submerged arc welding, and a preparation method and application thereof.

Background

In recent years, with the rapid rise of manufacturing industries such as shipbuilding, ocean engineering, high-rise buildings, bridges, engineering machinery and the like, in order to improve welding construction efficiency and reduce cost in the industries which use medium-thickness steel plates in large quantities, large-line energy welding methods such as gas electric vertical welding, FCB method submerged arc automatic welding, electroslag welding and the like are gradually adopted in response to the development trend of increasing the size and the span of members. The FCB (Flux copper Backing) method is a one-side welding and two-side forming welding method which comprises the steps of uniformly paving a Backing welding agent with the thickness of 4-6 mm on a plate-shaped copper plate, tightly attaching the Backing welding agent to the back of a steel plate by using an inflating hose jacking device, stacking a surface welding agent on the front of a groove, welding from the front and forming a back welding line, wherein the welding forming schematic diagram is shown in figure 1, and the configuration modes of electrodes and three welding wires are shown in figure 2. The FCB method is mainly applied to plate splicing welding of a plane section assembly line of a ship, when the FCB method is used for plate splicing welding of steel plates with the thickness of 10-40 mm, single-side welding and double-side forming can be achieved, workpieces do not need to be turned over, and compared with double-side submerged arc automatic welding, efficiency can be improved by 3-5 times. The heat input energy during the FCB welding can reach more than 200kJ/cm usually, when welding is carried out under such high heat input energy, the grains of weld metal are easy to grow seriously, and the single-pass welding has lower post-welding cooling rate than the multi-pass welding, so that the abnormal coarse-grained structures such as side plate bar ferrite, Wei-shi structures, upper bainite and the like are easy to form in the subsequent phase transformation process of the base material welding heat affected zone structure, the strength and toughness of a welding joint are seriously deteriorated, the probability of generating welding cracks is obviously increased, and the safe use of the whole component is affected. Because the current domestic structural steel and the welding materials matched with the steel can only bear the energy of a welding line below 50kJ/cm, the large-area popularization and application of high-efficiency welding methods such as FCB submerged arc welding and the like are severely restricted, and the potential of more than 20 FCB submerged arc automatic welding production lines introduced by domestic shipbuilding enterprises from abroad can not be fully exerted to date. Therefore, research and development of the steel for high heat input welding capable of bearing heat input of more than 50kJ/cm and the matched welding material thereof have attracted wide attention of domestic enterprises.

Chinese invention patent ZL201310135074.1 discloses a steel plate smelting method for improving high heat input welding performance; CN104004962A discloses 'a normalized steel plate for welding high heat input ocean engineering and its manufacturing method'; CN111500821A discloses 'a method for preparing steel for composite cored wire and large heat input welding'. With the support of the patent technologies, for over 10 years, part of domestic steel enterprises break through the long-term technical blockade abroad, and can manufacture TMCP-state EH40 and EH36 ship steel plates with welding linear energy of more than 500kJ/cm and thickness of 70mm and normalized EH36N ocean engineering steel plates with linear energy of more than 300kJ/cm and thickness of more than 80 mm. These steel sheets for shipbuilding for high heat input welding have been approved by multinational classification societies such as ABS, DNV, BV, KR, CCS, etc. and have been used for the construction of polar vessels, large FPSO (floating production storage vessel on the sea), etc. Unfortunately, at present, many welding material production enterprises in China still do not have the supply capacity of the welding material matched with the steel for high heat input welding, for example, FCB method high heat input submerged arc automatic welding solid welding wires and welding flux used by shipbuilding enterprises are almost all imported from japan enterprises at high price (about 2.5-3.0 ten thousand yuan/ton), and in order to get rid of the passive situation of long-term manmade, domestic steel enterprises, welding material manufacturers, shipbuilding enterprises, higher schools and scientific research institutes need to take the hands together to cooperate, and the localization process of the welding material matched with the steel for high heat input welding is promoted together.

Disclosure of Invention

The invention aims to provide a solid welding wire for FCB (flux cored arc welding) method large-linear-energy submerged arc welding, and a preparation method and application thereof.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the solid welding wire for FCB method large linear energy submerged arc welding comprises the following chemical components in percentage by weight:

0.06-0.09% of C, 0.12-0.28% of Si, 1.52-2.0% of Mn, 0.0001-0.3% of A, and the balance of Fe and inevitable impurities; wherein: the element A is one or more of Mg, Ca, Zr, RE and B.

The solid welding wire further comprises Ti, Ni and Cu in chemical components, wherein in the case, the content of Ti is 0.008-0.035 wt.%, the content of Ni is 0.05-0.8 wt.%, and the content of Cu is 0.05-0.8 wt.%.

Or the chemical components of the solid welding wire also contain Ti and V (Ni and Cu are not contained), wherein: the Ti content is 0.008-0.035 wt.%, and the V content is 0.01-0.06 wt.%.

When the chemical composition of the solid welding wire contains one or more of Mg, Ca, Zr, RE and B, the contents of the elements in percentage by weight are as follows: 0.0001-0.005% of Mg, 0.0001-0.008% of Ca, 0.0001-0.02% of Zr, 0.0001-0.02% of RE and 0.0001-0.002% of B; RE is rare earth element containing Ce or La.

The solid welding wire can further contain 0.001-0.03 wt.% of Al element in the chemical components.

The impurity requirements of the solid welding wire are as follows: p is less than or equal to 0.015 wt.%, S is less than or equal to 0.005 wt.%, N is less than or equal to 0.007 wt.%, and O is less than or equal to 0.006 wt.%.

The preparation method of the solid welding wire for FCB method large linear energy submerged arc welding comprises the following steps:

(1) adopting a converter smelting-LF furnace refining-continuous casting process to prepare a 130 x 130mm or 150 x 150mm continuous casting square billet according to the chemical components of the solid welding wire;

(2) placing the continuous casting square billets in a stacking mode for more than 24 hours, heating the continuous casting square billets to 1050-1150 ℃ through a stepping heating furnace, enabling the casting billets to be in the furnace for not less than 3.5 hours, then rolling the continuous casting square billets through a high-speed wire rod rolling mill, and controlling the rough rolling start temperature to 1020-1080 ℃ and the finish rolling start temperature to 900-950 ℃;

(3) after finish rolling, adopting a time-interval water cooling mode, controlling the spinning temperature to be 850-890 ℃, and finally preparing a welding wire steel wire rod with the diameter of 6-8 mm through stelmor delayed cooling, coil collection and other procedures;

(4) and preparing the welding wire steel wire rod into the solid welding wire.

In the step (1), when the molten steel reaches the LF furnace for refining, after the oxygen content is controlled to be less than or equal to 100ppm by adding ferromanganese or ferrosilicon and other weak deoxidation modes, adding Ti, then adding one or more of Mg, Ca, Zr, RE or B, controlling the adding interval time of each element to be less than or equal to 10min, and finally carrying out slag making, desulfurization and alloying in the LF furnace; and after the LF furnace refining is finished, controlling the mass percent of FeO and MnO in the slag to be less than or equal to 1.5%.

In the step (4), after the solid welding wire steel wire rod is sequentially subjected to the processes of shelling, acid washing, borax coating, rough drawing, tempering, fine drawing, copper plating and coiling, a finished solid welding wire with the diameter of 4-7 mm is manufactured and coiled into a coil with the inner diameter of 300-630 mm.

The solid welding wire is used for FCB method large linear energy submerged arc welding of structural steel plates with the thickness of less than 40mm, and the specific process is as follows: adopting imported or domestic welding flux, and welding the hot-rolled thick steel plate of the structural steel with the yield strength of 345-420 MPa by adopting an FCB method or other submerged arc welding methods within the range of welding heat input of 60-300 kJ/cm.

The weld metal mechanical properties that can be achieved are as follows: the yield strength is 450-560 MPa, the tensile strength is 470-680 MPa, the elongation is 20-28%, the 0 ℃ impact absorption energy is 163-207J, the-20 ℃ impact absorption energy is 116-143J, and the-40 ℃ impact absorption energy is 98-125J, and all indexes meet the relevant requirements of national standards such as GB 712-2011 structural steel for ships and ocean engineering, GB/T1591-2018 low-alloy high-strength structural steel and the like.

The design mechanism and the beneficial effects of the invention are as follows:

1. the manufacturing process of the welding wire steel wire rod takes common C-Mn steel as basic steel, adopts oxide Metallurgy (Oxides Metallurgy) technology, selects a proper alloy adding method through reasonable chemical composition design, utilizes chemical reaction in the metallurgical process to lead inclusions in the steel to be micronized and spheroidized and form high-melting-point composite inclusions with controllable chemical structure, and can effectively inhibit the coarsening of weld metal grains in the welding process by means of the composite inclusions and also induce and generate a large amount of fine acicular ferrite with large-angle grain orientation in the austenite/ferrite phase transition process of the weld metal, thereby ensuring that a welding joint has the strength and the low-temperature impact toughness matched with a base metal.

2. The welding wire is suitable for the FCB method of structural steel plates with the thickness of less than 40mm and the high heat input welding of other submerged arc welding machines in the manufacturing fields of ships, maritime works, buildings, bridges and the like.

3. The finished welding wire with the diameter of 4-7 mm is mainly suitable for large linear energy submerged arc welding of AH/DH/EH36, AH/DH/EH40, AH/DH/EH420 ship building steel plates and FCB (flux cored arc welding) method high-strength structural steel plates with low alloy and same strength grade within the range of heat input of 60-300 kJ/cm, and is also suitable for single-wire, double-wire and multi-wire submerged arc welding of the steel plates within the range of heat input of 60-300 kJ/cm.

Drawings

FIG. 1 is a schematic illustration of FCB process weld formation;

FIG. 2 is an FCB process welding electrode configuration;

FIG. 3 is a macroscopic metallographic photograph of a welded joint of an EH36 shipbuilding steel plate welded by an FCB method; wherein: (a) example 1 wire welding; (b) comparative example 1 wire welding.

FIG. 4 is a macroscopic metallographic photograph of a welded joint of a Q420C structural steel plate welded by an FCB method; wherein: (a) example 1 wire welding; (b) comparative example 1 wire welding.

Detailed Description

The invention is described in detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only, and the present invention is not limited to these examples, and any technical solutions formed by equivalent changes or equivalent substitutions should fall within the scope of the claims of the present invention.

Example 1

The method comprises the steps of adopting a converter smelting-LF furnace refining-continuous casting process, adopting an oxide metallurgy process when molten steel reaches the LF furnace refining, controlling the oxygen content to reach 45ppm through weak deoxidation of silicon and manganese, sequentially adding Ti, Mg, Al, Ca and B elements, adding the elements at intervals of 8min, then carrying out slagging, desulfurization and alloying in the LF furnace, and after the LF furnace refining is finished, feeding the molten steel into a continuous casting process to cast a 150 x 150mm square billet. The casting blank comprises the following chemical components in percentage by mass: 0.08% of C, 0.21% of Si, 1.57% of Mn, 0.010% of P, 0.003% of S, 0.22% of Ni, 0.20% of Cu, 0.015% of Ti, 0.003% of Mg, 0.003% of Ca and 0.003% of Al_T0.02%, 0.002%, 0.004%, 0.003%, and the balance of Fe and inevitable impurities.

And (2) stacking and placing the continuous casting square billets for about 24 hours, heating the continuous casting square billets to 1100 ℃ through a stepping heating furnace, keeping the casting billets in the furnace for 4.5 hours, then rolling the continuous casting square billets through a high-speed wire rod rolling mill, controlling the rough rolling starting temperature to 1050 ℃ and the finish rolling starting temperature to 920 ℃, adopting a section type water cooling mode after finish rolling, controlling the spinning temperature to 870 ℃, and finally preparing the wire rod steel wire rods with the diameters of 6.5mm and 8.0mm through processes of stelmor delayed cooling, coil collection and the like. The tensile mechanical properties of the two welding wire steel wire rods are shown in table 1.

TABLE 1 tensile mechanical properties of FCB method high heat input submerged arc welding wire steel wire rod

Wire rod diameter/mm	Rel/MPa	Rm/MPa	YR	A/％
					8.0	398	510	0.78	29
6.5	411	519	0.79	28

The obtained two specifications of wire rods are made into a welding wire with the diameter of 8mm by conventional processes of shelling, acid washing, borax coating, rough drawing, tempering, fine drawing, copper plating, coiling and the like, and the welding wire with the diameter of 6.4mm is coiled into a coil with the inner diameter of 630 mm; making a wire rod with the diameter of 6.5mm into a welding wire with the diameter of 4.8mm and winding the welding wire into a coil with the inner diameter of 630 mm; considering the requirement of double-wire submerged arc high-linear energy welding, partial wire rods with the diameters of 6.5mm are respectively manufactured into welding wires with the diameters of 4.0mm and 5.0mm and wound into coils with the inner diameters of 300 mm.

Comparative example 1

The process is also produced by adopting the converter smelting-LF furnace refining-continuous casting process, and only when the molten steel reaches the LF furnace for refining, the oxide metallurgical process is not adopted, namely, the deoxidation, slagging, desulfurization and alloying are carried out according to the traditional process, the alloy addition sequence is not required to be controlled, the oxygen content is not required to be controlled to be less than or equal to 100ppm, and special alloy elements such as Mg, RE, Zr, B and the like are not required to be added. After the refining, the alloy is continuously cast into a 150X 150mm square billet, and the chemical components of the alloy comprise, by mass, 0.09% of C, 0.10% of Si, 1.96% of Mn, 0.008% of P, 0.005% of S, 0.28% of Ni, 0.19% of Cu, 0.02% of Al, 0.005% of N, 0.003% of O, 0.016% of Ti, 0.003% of Ca and the balance of Fe and inevitable impurities.

And (2) stacking and placing the continuous casting square billets for about 24 hours, heating the continuous casting square billets to 1100 ℃ through a stepping heating furnace, keeping the time of the casting billets in the furnace for 4.5 hours, then rolling the continuous casting square billets through a high-speed wire rod rolling mill, controlling the rough rolling initial rolling temperature 1050 ℃ and the finish rolling initial rolling temperature 920 ℃, cooling the continuous casting square billets with water after finish rolling, controlling the spinning temperature 870 ℃, and finally preparing the wire rod steel wire rods with the diameters of 6.5mm and 8.0mm through stelmor delayed cooling, coil collection and other procedures. Tensile mechanical properties of two comparative example 1 wire-wound steel wire rods are shown in table 2.

TABLE 2 tensile mechanical properties of FCB submerged arc welding wire steel wire rod in comparative example 1

Wire rod diameter/mm	Rel/MPa	Rm/MPa	YR	A/％
					8.0	410	508	0.81	27
6.5	423	518	0.82	26

The obtained two specifications of wire rods are made into a welding wire with the diameter of 8mm by conventional processes of shelling, acid washing, borax coating, rough drawing, tempering, fine drawing, copper plating, coiling and the like, and the welding wire with the diameter of 6.4mm is coiled into a coil with the inner diameter of 630 mm; a wire rod of 6.5mm diameter was made into a wire of 4.8mm diameter and wound into a coil of 630mm inner diameter.

Example 2

Welding wires with the diameter of 4.8mm obtained in example 1 and comparative example 1 are respectively placed in an L pole and a T1 pole of an FCB method submerged arc automatic welding machine, a welding wire with the diameter of 6.4mm is placed in a T2 pole, a domestic 34mm thick EH36 shipbuilding steel plate is adopted to match with imported flux NSH-1RM/NSM-50M of Nissan iron (strain), FCB method large linear energy submerged arc welding comparative tests of the welding wires of example 1 and comparative example 1 are carried out under the parameter conditions shown in Table 3 as reference, meanwhile, the comparative tests of the welding wires of example 1 and the imported Y-DL welding wires of Nissan iron (strain) are carried out under the same parameter conditions shown in Table 3, the measured mechanical property data of the welding joints of the group are shown in Table 4, and the macro metallographic photograph of the welding joints of example 1 and comparative example 1 is shown in FIG. 3. As can be seen from the data in Table 4, the cold bending property of the metal after welding of the comparative example welding wire is unqualified; and the single value and the average value of the low-temperature impact energy at the temperature of-40 ℃ all can not reach more than 34J required by the GB 712-2011 standard of structural steel for ships and ocean engineering. And the mechanical property indexes of the weld metal after the welding wire is welded in the embodiment 1 all meet the GB 712-2011 standard requirement, and the single value and the average value of the-40 ℃ low-temperature impact energy all far exceed the standard specification of more than or equal to 34J, thereby reaching the level of the Japanese Nippon iron (Co.) import Y-DL welding wire. Therefore, the FCB method high-heat-input submerged arc welding solid welding wire has the alternative import condition, and is expected to be popularized and applied in a large area as soon as possible under the tripod force cooperation of people in the fields of domestic ships and ocean engineering manufacturing.

TABLE 3 FCB high heat input submerged arc welding EH36 boat deck test parameters

TABLE 4 mechanical properties of large heat input submerged arc welding EH36 ship plate weld joint by FCB method

Example 3

The welding wire with the diameter of 4.8mm obtained in example 1 and comparative example 1 is used as the first two wires (L pole and T1 pole) of the FCB submerged arc welding machine, the welding wire with the diameter of 6.4mm is used as the rear wire (T2 pole) of the FCB submerged arc welding machine, a Q420C steel plate with the thickness of 30mm used for the current building of a deep channel immersed tube is matched with a domestic TGF-55E/TGF-B welding flux, a comparison test of FCB method large-line energy submerged arc welding is carried out under the parameter conditions shown in Table 5, the mechanical property of a welding joint is shown in Table 6, and a macroscopic metallographic photograph of the welding joint is shown in FIG. 4. It can be easily found from the data in table 6 that when the welding wire in example 1 is matched with a domestic flux and used for welding a low-alloy high-strength structural steel thick plate with the yield strength of 420MPa, the toughness performance of a welding joint is still reasonably matched, all mechanical properties meet the standard requirements of GB/T1591-2018 'Low-alloy high-strength structural steel', and the cold bending performance of the metal welded by the welding wire in comparative example 1 is unqualified, and the single value and the mean value of the-20 ℃ low-temperature impact energy do not meet the standard requirements of GB/T1591-2018. Therefore, the efficient FCB method submerged arc welding mode and the high heat input welding solid welding wire are matched with the domestic welding flux, and are expected to be popularized and applied in the fields of building, bridge, engineering machinery manufacturing and the like which use a large amount of low-alloy high-strength structural steel thick plates.

TABLE 5 FCB Large Heat input submerged arc welding Q420C Steel plate test parameters

TABLE 6 FCB method high heat input submerged arc welding Q420C steel plate weld joint mechanical properties

Example 4

The welding wires with the diameters of 4.0mm and 5.0mm manufactured in the embodiment 1 are respectively used as a front wire (L pole) and a rear wire (T1 pole) of a twin-wire submerged arc welding machine to be matched with a domestic TGF-55E welding flux, a domestic 30mm thick Q420C steel plate is adopted to carry out twin-wire submerged arc automatic welding under the parameter conditions shown in the table 7, the measured mechanical properties of a welding joint are shown in the table 8, and the test result of the table 8 shows that the welding wire has good comprehensive mechanical properties even when the welding wire is used for the twin-wire or multi-wire large-linear-energy submerged arc welding of a low-alloy high-strength structural steel plate, and each mechanical property of a welding seam metal can meet the standard requirements of GB 159T 1-2018.

TABLE 7 test parameters of the welding wire of the examples for twin wire submerged arc welding of Q420C steel sheet

TABLE 8 example 1 weld wire for twin wire submerged arc welding Q420C Steel plate weld joint mechanical properties

Example 5:

the difference from the embodiment 1 is that: the casting blank of the embodiment comprises the following chemical components in percentage by mass: 0.085% of C, 0.20% of Si, 1.98% of Mn, 0.015% of P, 0.003% of S, 0.03% of V, 0.015% of Ti, 0.007% of Zr, 0.0025% of Ca, 0.0015% of B, 0.003% of N, 0.0025% of O and the balance of Fe and inevitable impurities.

Example 6:

the difference from the embodiment 1 is that: the casting blank of the embodiment comprises the following chemical components in percentage by mass: 0.086 percent of C, 0.23 percent of Si, 1.57 percent of Mn, 0.010 percent of P, 0.002 percent of S, 0.05 percent of V, and Al_T0.02%, Ti 0.013%, Ce 0.005%, B0.001%, N0.004%, O0.002%, and the balance Fe and inevitable impurities.

Example 7:

the welding wires with the diameters of 4.0mm and 5.0mm prepared in the examples 5-6 are respectively used as a front wire (L pole) and a rear wire (T1 pole) of a double-wire submerged arc welding machine to be matched with a domestic TGF-55E welding flux, domestic 30mm thick Q420C steel plate is adopted to carry out double-wire submerged arc automatic welding under the parameter conditions shown in the table 7, the measured mechanical properties of a welding joint are shown in the table 9, and the mechanical properties of the welding seam metal can be seen to all meet the standard requirements of GB/T1591-2018. Therefore, the welding wire has strong chemical component adaptability and wider process window, and is beneficial to realizing batch manufacturing and large-area popularization and application under the condition of the domestic existing equipment.

TABLE 9 examples 5-6 weld wires for weld joint mechanical properties of twin wire submerged arc welding Q420C steel plates

Claims

1. A solid welding wire for FCB method large heat input submerged arc welding is characterized in that: the solid welding wire comprises the following chemical components in percentage by weight:

2. The solid wire for large heat input submerged arc welding by the FCB process according to claim 1, wherein: the solid welding wire further comprises Ti, Ni and Cu in chemical components, wherein the content of Ti is 0.008-0.035 wt.%, the content of Ni is 0.05-0.8 wt.%, and the content of Cu is 0.05-0.8 wt.%.

3. The solid wire for large heat input submerged arc welding by the FCB process according to claim 1, wherein: the solid welding wire further comprises Ti and V in chemical components, wherein the content of Ti is 0.008-0.035 wt.%, and the content of V is 0.01-0.06 wt.%.

4. The solid wire for large heat input submerged arc welding by the FCB process according to claim 1, wherein: when the solid welding wire comprises one or more of Mg, Ca, Zr, RE and B in chemical components, the weight percentage of each element is as follows: 0.0001-0.005% of Mg, 0.0001-0.008% of Ca, 0.0001-0.02% of Zr, 0.0001-0.02% of RE and 0.0001-0.002% of B; RE is rare earth element containing Ce or La.

5. The solid wire for large heat input submerged arc welding by the FCB process according to claim 1, wherein: the solid welding wire can further contain 0.001-0.03 wt.% of Al element in the chemical components.

6. The solid wire for large heat input submerged arc welding by the FCB process according to any one of claims 1 to 5, wherein: the impurity requirements of the solid welding wire are as follows: p is less than or equal to 0.015 wt.%, S is less than or equal to 0.005 wt.%, N is less than or equal to 0.007 wt.%, and O is less than or equal to 0.006 wt.%.

7. The method for producing a solid wire for high heat input submerged arc welding by the FCB process according to any one of claims 1 to 5, wherein: the method comprises the following steps:

(4) and preparing the welding wire steel wire rod into the solid welding wire.

8. The method of manufacturing a solid wire for high heat input submerged arc welding by the FCB process according to claim 7, wherein: in the step (1), when molten steel reaches an LF furnace for refining, adding Ti element after controlling the oxygen content to be less than or equal to 100ppm by adding ferromanganese or ferrosilicon and other weak deoxidation modes, then adding one or more of Mg, Ca, Zr, RE or B elements, controlling the adding interval time of each element to be less than or equal to 10min, and finally carrying out slag forming, desulfurization and alloying of the LF furnace; and after the LF furnace refining is finished, controlling the mass percent of FeO and MnO in the slag to be less than or equal to 1.5%.

9. The method of manufacturing a solid wire for high heat input submerged arc welding by the FCB process according to claim 7, wherein: in the step (4), the solid welding wire steel wire rod is sequentially subjected to the processes of shelling, acid washing, borax coating, rough drawing, tempering, fine drawing, copper plating and coiling to prepare a finished solid welding wire with the diameter of 4-7 mm, and the finished solid welding wire is coiled into a coil with the inner diameter of 300-630 mm.

10. Use of a solid wire according to any one of claims 1 to 5 for high heat input submerged arc welding in the FCB process, wherein: the solid welding wire is used for FCB method large linear energy submerged arc welding of a steel plate with a structure of which the thickness is less than 40mm, and the specific process is as follows: adopting imported or domestic welding flux, and welding the hot-rolled thick steel plate of the structural steel with the yield strength of 345-420 MPa by adopting an FCB method or other submerged arc welding methods within the range of welding heat input of 60-300 kJ/cm.