CN113118579A

CN113118579A - Fe-Cr-Al alloy welding material welding process on surface of metal plate

Info

Publication number: CN113118579A
Application number: CN202110263070.6A
Authority: CN
Inventors: 张有鹏; 杨晟; 席斌
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2021-03-10
Filing date: 2021-03-10
Publication date: 2021-07-16

Abstract

The invention relates to a Fe-Cr-Al alloy welding material welding process on the surface of a metal plate, which adopts laser welding to weld, wherein the power of the laser welding is 1450-1550, the welding speed is 16-20 mm/s, the wire feeding speed is 90-110 cm/min, and the defocusing amount is + 55-65 mm. According to the invention, the welding process parameters are changed to optimize the texture performance, so that the problem of cracking of the overlaying layer of the alloy welding material is effectively solved.

Description

Fe-Cr-Al alloy welding material welding process on surface of metal plate

Technical Field

The invention relates to the technical field of welding, in particular to a process for welding Fe-Cr-Al alloy welding materials on the surface of a metal plate.

Background

Since Fe-Cr-Al alloy has excellent Lead-bismuth corrosion resistance, it is considered to be a promising material for a Lead-cooled Fast Reactor (LFR), one of the fourth-generation nuclear reactors. However, because the ductility and toughness of the alloy are poor and the alloy is not a precedent for application in nuclear power products, a great deal of research work is needed on how to apply the alloy in actual products. At present, when the Fe-Cr-Al alloy material is applied, a surfacing layer of the Fe-Cr-Al alloy material is easy to crack when a bending test is carried out, which seriously hinders the popularization and the application of the Fe-Cr-Al alloy material.

Disclosure of Invention

The invention aims to solve the problem of cracking of a build-up welding layer after welding of Fe-Cr-Al alloy welding materials, and provides a Fe-Cr-Al alloy welding material welding process on the surface of a metal plate.

The purpose of the invention is realized by the following technical scheme:

a welding process for Fe-Cr-Al alloy welding materials on the surface of a metal plate adopts laser welding for welding, the power of the laser welding is 1450-1550, the welding speed is 16-20 mm/s, the wire feeding speed is 90-110 cm/min, and the defocusing amount is + 55-65 mm.

Preferably, the power of the laser welding is 1500W, the welding speed is 18mm/s, the wire feeding speed is 100cm/min, and the defocusing amount is +60 mm.

Preferably, the equipment adopted by the laser welding comprises a FANUC robot, an MFSC3000X single-module continuous fiber laser and a WF007A multifunctional automatic argon arc welding wire filling machine.

Preferably, the base material is a stainless steel plate, and the welding material is a Fe-Cr-Al alloy welding wire.

Preferably, the thickness of the stainless steel plate is 30-50 mm, and the diameter of the Fe-Cr-Al alloy welding wire is 1-1.4 mm.

Preferably, the thickness of the stainless steel plate is 40mm, and the diameter of the Fe-Cr-Al alloy welding wire is 1.2 mm.

Preferably, the chemical composition of the Fe-Cr-Al alloy welding wire is as follows: 0.10 wt.% Ni, 10.9 wt.% Cr, 4.68 wt.% Al, 0.020 wt.% C, 0.28 wt.% Si, 0.20 wt.% Mn, 0.21 wt.% Ti, 0.014 wt.% Cu, 0.38 wt.% Nb, and Ta, the balance being Fe, S <0.001 wt.%.

Preferably, during laser welding, argon is used as the shielding gas, and the flow rate is more than 25L/min.

Preferably, the build-up welding is carried out by laser welding, and the thickness of a single layer is below 1 mm.

After extensive and intensive research and a large number of experiments, the invention discovers that the problem of cracking of a surfacing layer after welding of the Fe-Cr-Al alloy welding material can be solved according to the welding process method adopted by the invention, and particularly when the power is 1500W, the welding speed is 18mm/s, the wire feeding speed is 100cm/min, and the defocusing amount is +60mm, the thickness of the surfacing layer is 0.6-0.7mm after PT detection by polishing, a fine grain region appears on the surface of a tissue, no air holes exist, the surfacing test plate can not crack after lateral bending, and the surfacing test plate can pass the lateral bending test.

Drawings

FIG. 1 is a photograph showing the formation of a weld by manual argon arc welding;

FIG. 2 is a liquid permeation diagram of a test plate of manual argon arc welding surfacing;

FIG. 3 is a diagram illustrating physical and chemical sampling of a manual argon arc welding bead welding test plate;

FIG. 4 is a pictorial view of a lateral bending test result of a manual argon arc weld stack sample;

FIG. 5 is a macro-microscopic metallographic photograph of a manual argon arc weld build-up weld specimen;

FIG. 6 is a weld forming photograph of a laser welding trial plate using a first set of data;

FIG. 7 is a side bend test result object diagram of a laser welding test panel using a first set of data;

FIG. 8 is a metallographic photograph of a laser welded panel using a first set of data;

FIG. 9 is a photograph of a laser welding trial plate illustrating weld formation using a second set of data;

FIG. 10 is a diagram of PT detection results of a laser welding trial plate using a second set of data;

FIG. 11 is a side bend test result object diagram of a laser welding test panel using a second set of data;

FIG. 12 is a macroscopic metallographic photograph of a laser welded plaque using a second set of data;

fig. 13 is a microscopic metallographic photograph of a laser welded plaque using a second set of data.

Detailed Description

The present application is directed to a method for solving the cracking problem of a weld overlay after welding of an Fe-Cr-Al alloy welding material, and the present invention will be described in detail with reference to the accompanying drawings and specific examples.

Base material: a 316L stainless steel plate with the thickness of 40 mm;

welding materials: the specific specification of the Fe-Cr-Al alloy welding wire with the diameter of 1.2mm is detailed in Table 1.

TABLE 1 weld material Specification

The chemical composition of the welding wire is analyzed by adopting ASTMA751, C and S are measured by adopting a carbon-sulfur analyzer (model CS600), other elements are measured by adopting an ICP-OES inductively coupled plasma emission spectrometer (model ICP725-ES), the chemical composition of the welding wire is obtained and is shown in Table 2, and the main chemical composition of the welding material is Fe-Cr-Al:

TABLE 2 Photosolder wire chemistry (Wt.%)

Ni	Cr	Al	C	Si	Mn	Fe	Ti	Cu	Nb+Ta	S
											0.10	10.9	4.68	0.020	0.28	0.20	Balance of	0.21	0.014	0.38	<0·001

The test equipment used:

argon arc welding equipment: a Japan Song lower IGBT control direct current TIG arc welding power YC400 TX;

laser welding equipment: a FANUC robot, an MFSC3000X (machine box type) single-module continuous fiber laser and a WF007A multifunctional automatic argon arc welding wire filling machine;

welding by adopting argon arc welding equipment

Manual argon arc welding is adopted for surfacing, specific welding parameters are detailed in a table 3, welding seam forming is shown in a table 1, 3 layers of surfacing are totally formed, the thickness of the surfacing layer is about 3mm, and the local stacking height is about 10mm (deposited metal chemical analysis sampling is carried out).

TABLE 3 welding parameters

And after welding, polishing and grinding the surface of the overlaying layer, carrying out liquid permeation detection, finding a long crack at the center of the test plate, polishing and removing the crack as shown in a test plate liquid permeation diagram of fig. 2, and finding that the crack penetrates through the whole overlaying layer and directly reaches the base metal. Aiming at the cracking phenomenon of a surfacing layer in a bending test, the judgment is caused by the characteristics of the material, a parameter test is firstly carried out, and then optimization is carried out after good forming parameters are obtained so as to improve the performance of the material.

Welding by laser welding

Argon arc welding surfacing has a serious surfacing layer cracking phenomenon, and after the research of the inventor, laser welding is adopted. The condition of using argon tungsten-arc welding to carry out a surfacing test on the material is investigated, the severe cracking phenomenon of the surfacing layer is known when the bending test is carried out, the judgment is caused by the characteristics of the material, a parameter test is carried out firstly, and the optimization is carried out after good forming parameters are obtained.

After preliminary tests are performed, the first set of welding parameters obtained for good forming is: the power is 1600-; the protective gas adopts argon, and the flow rate is more than 25L/min. The parameters are used for surfacing welding of the test plate, and a sample is taken for lateral bending test and metallographic examination, and the result proves that the effect of using the parameters is improved to a certain extent compared with argon tungsten-arc welding, but the improvement is still limited, and the phenomenon of cracking at multiple positions still exists.

The inventors have conducted extensive studies to find that the finer grain size is more favorable for welding, i.e. the welding wire with the smallest possible diameter (e.g. 0.2mm) is used, however, the diameter of the welding wire is limited by the wire feeding equipment, and therefore, the parameter adjustment can only consider how to obtain finer grains.

The inventors have studied intensively again, and the degree of grain growth depends on the residence time at high temperature, so the optimization of the parameters is directed to minimize the heat input, increase the welding speed to increase the cooling speed, and match it with a higher wire feeding speed to obtain a thinner overlay layer, etc.

Finally, through a large number of experiments, excellent welding process parameters are obtained: i.e. the second set of molding-stable parameters: the power is 1500W, the welding speed is 18mm/s, the wire feeding speed is 100cm/min, the defocusing amount is +60mm, and the set of parameters are used for surfacing the test plate to obtain good effects after a lateral bending test and a metallographic examination are carried out.

The following are specific test results of the above welding

(1) Dissecting manual argon arc welding surfacing test plate

Physical and chemical sampling is shown in FIG. 3, and the contents of the physical and chemical tests are shown in Table 4.

TABLE 4 contents of physical and chemical tests

The results of the undiluted deposited metal chemistry tests are shown in table 5.

TABLE 5 undiluted deposited metal chemistry (Wt.%)

C	Si	Mn	P	S	Ni	Cr	Mo
								0.018	0.30	0.22	0.012	0.003	0.11	9.37	0.029
V	Co	Cu	Ti	Nb	W	Al
								0.026	0.013	0.022	0.21	0.46	0.15	3.37

Build-up welding layer HV₁₀The hardness test results are shown in Table 6.

TABLE 6HV₁₀Test results

Region of parent material	185，188，181
		Heat affected zone	211，209，196
Build-up welding layer	265，216，200

The results of the weld overlay bending test and the side bending test are shown in fig. 4, both samples crack, and the macro-micro metallographic photograph is shown in fig. 5, so that the welding effect is poor. From the crack walk direction, the origin point of the crack is at the position of the weld line and extends upwards along the weld grain boundary. In the weld dilution zone near the crack origin, feathered upper bainite was found to be present, and brittleness of the structure and stress of the weld were the main causes of cracking. The upper bainite is mainly due to the chemical composition of the weld dilution zone and to the excessively low preheat and interlaminar temperatures. The weld structure was ferrite + granular brittle precipitates, and from the results of the bending test, it was found that the weld plasticity was poor, which was also the cause of such large expansion.

(2) Dissecting the laser welding test plate

The first group of parameter effect photographs are shown in FIG. 6, the side bending test results are shown in FIG. 7, the sample thickness is 10mm, the pressure head diameter is 40mm, the bending is 180 degrees, the metallographic photographs are shown in FIG. 8, the effect of using the group of parameters is improved to a certain extent compared with the argon tungsten-arc welding, but a plurality of cracking phenomena still exist. The weld overlay obtained from the first set of parameters is about 1mm thick, has coarse texture grains, and can observe air holes; after lateral bending, a plurality of cracks appear, and the cracking depth exceeds half of the thickness of the sample.

When the second set of data was laser welded, the weld surface forming effect was as shown in fig. 9, the PT test results were as shown in fig. 10, the side bending test results were as shown in fig. 11, the specimen thickness was 10mm, the indenter diameter was 40mm, the bend was 180 °, the macroscopic metallographic photograph was as shown in fig. 12, and the microscopic metallographic photograph was as shown in fig. 13. After the parameters are optimized, the thickness of the overlaying layer is 0.6-0.7mm after grinding and PT detection (no defect is found in PT), a fine grain area is formed on the surface of the structure, no air hole is found, and no crack is found after lateral bending. The welding process parameters adopted by the invention are as follows: the power is 1500W, the welding speed is 18mm/s, the wire feeding speed is 100cm/min, the defocusing amount is +60mm, the surfacing test plate is built by using the group of parameters, the surfacing test plate passes a lateral bending test, and the problem of cracking of a surfacing layer is solved by changing welding process parameters to control the grain size.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. A welding process for Fe-Cr-Al alloy welding materials on the surface of a metal plate is characterized in that laser welding is adopted for welding, the power of the laser welding is 1450-1550, the welding speed is 16-20 mm/s, the wire feeding speed is 90-110 cm/min, and the defocusing amount is + 55-65 mm.

2. The process of claim 1, wherein the laser welding power is 1500W, the welding speed is 18mm/s, the wire feeding speed is 100cm/min, and the defocusing amount is +60 mm.

3. The process of claim 2, wherein the equipment used for laser welding comprises a FANUC robot, an MFSC3000X single-module continuous fiber laser, and a WF007A multifunctional automatic argon arc welding filler wire machine.

4. The process of claim 1, wherein the base material is a stainless steel plate, and the welding material is a Fe-Cr-Al alloy welding wire.

5. The process of claim 4, wherein the thickness of the stainless steel plate is 30-50 mm, and the diameter of the Fe-Cr-Al alloy welding wire is 1-1.4 mm.

6. The process of claim 5, wherein the thickness of the stainless steel plate is 40mm, and the diameter of the Fe-Cr-Al alloy welding wire is 1.2 mm.

7. The process of claim 1, wherein the welding wire comprises the following chemical components: 0.10 wt.% Ni, 10.9 wt.% Cr, 4.68 wt.% Al, 0.020 wt.% C, 0.28 wt.% Si, 0.20 wt.% Mn, 0.21 wt.% Ti, 0.014 wt.% Cu, 0.38 wt.% Nb, and Ta, the balance being Fe, S <0.001 wt.%.

8. The process of claim 1, wherein the welding is performed by argon gas as a shielding gas.

9. The process of claim 8, wherein the flow rate of the shielding gas is greater than 25L/min.

10. The process for welding Fe-Cr-Al alloy welding materials on the surface of a metal plate according to claim 1, wherein laser welding is adopted for overlaying, and the thickness of a single layer is less than 1 mm.