CN113969343A - Method for improving performance of high-strength steel laser tailor-welded joint - Google Patents
Method for improving performance of high-strength steel laser tailor-welded joint Download PDFInfo
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- CN113969343A CN113969343A CN202010720760.5A CN202010720760A CN113969343A CN 113969343 A CN113969343 A CN 113969343A CN 202010720760 A CN202010720760 A CN 202010720760A CN 113969343 A CN113969343 A CN 113969343A
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- heating
- strength steel
- laser tailor
- welded joint
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 55
- 239000010959 steel Substances 0.000 title claims abstract description 55
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000010438 heat treatment Methods 0.000 claims abstract description 80
- 238000003466 welding Methods 0.000 claims abstract description 41
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 11
- 239000011159 matrix material Substances 0.000 claims abstract description 10
- 238000001816 cooling Methods 0.000 claims abstract description 9
- 230000007246 mechanism Effects 0.000 claims description 7
- 150000003839 salts Chemical class 0.000 claims description 7
- 239000007788 liquid Substances 0.000 claims description 5
- 230000000694 effects Effects 0.000 claims description 4
- 238000010791 quenching Methods 0.000 claims description 3
- 238000005192 partition Methods 0.000 claims description 2
- 239000000758 substrate Substances 0.000 claims description 2
- 210000001503 joint Anatomy 0.000 abstract 1
- 238000004519 manufacturing process Methods 0.000 description 10
- 230000008569 process Effects 0.000 description 7
- 239000000463 material Substances 0.000 description 4
- 238000009864 tensile test Methods 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 229910000617 Mangalloy Inorganic materials 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 239000010953 base metal Substances 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910000797 Ultra-high-strength steel Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 125000000118 dimethyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
- C21D1/44—Methods of heating in heat-treatment baths
- C21D1/46—Salt baths
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
- C21D1/44—Methods of heating in heat-treatment baths
- C21D1/50—Oil baths
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/20—Bonding
- B23K26/21—Bonding by welding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/70—Auxiliary operations or equipment
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
The invention belongs to the field of welding, and discloses a method for improving the performance of a laser tailor-welded joint of a high-strength steel plate, wherein a high-strength steel matrix contains a residual austenite structure with the volume fraction of 5-40%; after the joint is subjected to laser tailor-welding in a butt joint mode, cooling the joint in an air environment, and then heating the joint; the heating temperature is 100-300 ℃, the heating time is 3 seconds-20 minutes, and the lower the heating temperature is, the longer the corresponding heating time is; the postweld heat treatment method can greatly improve the strength and the elongation of the joint.
Description
Technical Field
The invention relates to the field of welding of high-strength steel plates, in particular to a welding method of a high-strength steel plate containing an austenite structure.
Background
In the automobile manufacturing industry, the requirements of reducing the weight of an automobile, realizing energy conservation and emission reduction, improving the collision safety of the automobile and the like promote the application requirement of steel with higher strength and higher toughness in the automobile body manufacturing to increase. In order to simultaneously improve the strength and toughness of the steel plate, a relatively large amount of alloying elements are generally added, a relatively complicated heat treatment process is used to obtain a single-phase, dual-phase or multi-phase structure containing retained austenite, and the retained austenite is used to induce martensite nucleation under the action of plastic deformation, so that the strength and toughness of the steel plate are simultaneously improved. The third generation high strength steel is developed rapidly, comprises Q & P (quenching distribution) steel, medium manganese steel, TBF (transformation induced plasticity bainite ferrite) steel and the like, and has wide application prospect.
However, in the welding process of the material, the phase change of the welding seam and the original structure of the heat affected zone occurs under the action of heat, the remelting of alloy elements occurs segregation, and the large thermal temperature gradient causes the uneven distribution of the structure and the stress. For ultrahigh-strength steel and third-generation high-strength steel, the original matrix structure and the stress state are changed, so that the mechanical property of a welded joint is weakened, and the requirements of a subsequent production process and safety on the strength of the joint cannot be met. Therefore, improving the strength and toughness of the welded joint is a key factor in determining the scale application of high-strength steel.
Patent publication No. CN108356417A (hereinafter referred to as patent document 1) and patent publication No. CN108296638B (hereinafter referred to as patent document 2) each provide a method of laser splicing and post-weld heat treatment of steel sheets.
Patent document 1 describes a method for improving joint plasticity by butt laser welding and postweld heat treatment of manganese steel sheets with high product of strength and elongation, wherein the heat treatment process comprises the steps of placing a workpiece in a heating furnace at 650-750 ℃, keeping the temperature thoroughly for 5 +/-2 min, and keeping the temperature for 10-3 h. Patent document 2 describes a method of arc welding and post-welding annealing of a dual-phase high-strength steel, wherein the annealing temperature is 550 to 720 ℃, and the holding time is 60 to 186 min. The above heat treatment method requires a high heating temperature, and therefore, patent document 1 also describes limitations such as "spraying the surface of the welded sample plate with an oxidation preventing treatment before heat treatment" and "using a vacuum heat treatment furnace" to prevent the quality of the sample from being damaged by the high-temperature treatment for a long time. Further, patent document 1 proposes the effect of heat treatment in that "the martensite structure in the weld zone is decomposed and reverse transformed to form an austenite structure and a ferrite structure" and "the hardness in the weld zone is reduced" to improve the weld joint performance.
In actual production and manufacturing, particularly in automobile production, it is generally required to simplify the processes and man-hours and improve the production efficiency. Patent documents 1 and 2 have disadvantages such as high heat treatment temperature requirements and strict process requirements, and it is difficult to meet the demand for efficient production.
Disclosure of Invention
In order to improve the welding quality of the high-strength steel plate containing the austenitic structure, the invention provides a welding method of the high-strength steel plate, and the technical scheme provided by the invention is as follows: butt-jointing two workpieces and performing laser welding, wherein the two workpieces comprise at least one high-strength steel, the matrix structure of the high-strength steel contains austenite, the thickness of the high-strength steel is less than 3.0mm, and after the workpieces are subjected to laser tailor-welding, the workpieces are subjected to heating treatment at the heating temperature of 100-300 ℃ for 3 seconds-30 minutes.
In a preferred embodiment, the relationship between the heating time T and the heating temperature T is as follows: t is 26342E (-0.029T), wherein T is in units of s and T is in units of C, and the heating time is calculated as the time suitable for achieving the best effect at the corresponding temperature, and the specific time can be adjusted within the range of +/-20% on the basis.
In another preferred embodiment, the high strength steel matrix contains an austenite structure volume fraction of 5% to 40%.
In another preferred example, the tensile strength of the high-strength steel matrix material is greater than 600 MPa.
In another preferred embodiment, the high strength steel substrate is a quench and partition steel (Q & P).
In another preferred example, after the laser tailor-welding is completed, the laser tailor-welding is cooled in an air environment and then is subjected to heating treatment, and the cooling time is less than 12 hours.
In another preferred example, the heating treatment process is implemented by conveying the workpiece into a heating environment by using a motion mechanism, and removing the workpiece into an air environment for natural cooling after reaching the heating time.
In another preferred example, the heating treatment mode is heating by a liquid medium, and the whole workpiece or a welding area is immersed in oil or salt in a heating temperature range; the oil is used for conventional heat treatment oil bath, and the salt is used for low-temperature salt bath.
In another preferred example, the heating treatment mode is heating by an air medium, and the whole workpiece is conveyed to a heating furnace for heating.
The invention has the beneficial effects that: the method improves the welding quality of the laser tailor-welding containing the high-strength steel with the austenitic structure, and in addition, the heating treatment process can realize continuous batch treatment of the welded parts, so that the production efficiency is greatly improved.
Drawings
FIG. 1 is a QP980 steel laser tailor welded component with joint tensile failure without subsequent heat treatment.
FIG. 2 is a schematic illustration of a laser tailor welded workpiece.
FIG. 3 is a schematic view showing the heating process of the welded workpiece as a whole by moving the welded workpiece into and out of the heating furnace through the conveyor.
FIG. 4 shows tensile failure of the joint after the laser tailor-welded QP980 steel workpiece was placed in a 100 ℃ oil bath furnace and heated for 20 minutes.
FIG. 5 shows tensile failure of the joint after the laser tailor-welded QP980 steel workpiece was heated in a 250 ℃ oil bath furnace for 15 seconds.
FIG. 6 is a drawing of a joint at tensile failure after placing a QP980 steel laser tailor welded part in a 250 deg.C oil bath furnace heated for 10 seconds.
Reference numerals: 1-welding a workpiece by high-strength steel laser tailor welding; 11-high strength steel plate; 12-butt welding seam of high-strength steel; 2-a conveyor belt mechanism; and 3, heating the furnace.
Detailed Description
The present invention will be described in detail below with reference to fig. 1 to 6, and the technical solutions in the embodiments of the present invention will be clearly and completely described, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
Comparative example 1
Two high-strength steel plates containing an austenite matrix structure and having the thickness of 1.0mm and the tensile strength of 1037MPa are butted together, the two high-strength steel plates are welded together by laser welding to form a welded workpiece, a standard tensile test sample is manufactured by cutting the sample and tested, as shown in figure 1, a tensile test result shows that a tensile fracture phenomenon exists in a welding seam area of the welded workpiece, and a welded joint is weak.
Example 1
As shown in the figure 2-3, two Q & P980 high-strength steel plates 11 which are 1.0mm in thickness and 1037MPa in tensile strength and contain austenite matrix structures are butted together, the two high-strength steel plates are welded together by laser welding to form a welding workpiece 1, after cooling for 1 hour in an air environment, the welding workpiece 1 is placed on a conveyor belt mechanism 2, the single welding workpiece 1 is placed at intervals, the conveyor belt mechanism 2 moves at a certain speed, the welding workpiece is sent into the range of a heating furnace 3, the temperature of the heating furnace is 300 ℃, and the time from the welding workpiece 1 to the heating furnace is 3s to 30 minutes. Wherein, the conveying speed of the conveyor belt mechanism 2 can be adjusted to change the time range of the welding workpiece in the heating furnace 3; in addition, the heating temperature of the heating device 3 can be adjusted to change the temperature range of the welding workpiece; the inside of the heating furnace 3 is an air or liquid (such as a certain oil bath or salt bath) environment. When the heating medium is liquid, the horizontal plane of the position of the feeding and discharging part of the conveying mechanism 2 is higher than the position of the feeding and discharging part in the heating furnace 3, so that the normal existence of the liquid environment is ensured.
When the temperature is 100 ℃, the heating mode is oil bath, specifically dimethyl silicone oil, the welded workpiece is heated for 20 minutes, and then the standard tensile sample piece is cut after cooling, as shown in fig. 4, the tensile test result shows that the sample piece is broken in the base metal area, which indicates that the joint performance is improved after the heating treatment, and the welded joint is changed into the base metal breakage.
Example 2
In this example, similar to example 1, the heating time was 18.7s calculated according to the formula T26342 × e (-0.029 × T) at 250 ℃ of the oil bath heating temperature, and after actual heating for 15s, a standard tensile sample was taken, and as shown in fig. 5, the tensile test results show that the sample was broken in the base material region, indicating that the joint performance was improved after the above-described heating treatment, and the transition from the weld breakage to the base material breakage was achieved. When the actual heating time is reduced to 10s, the test result of stretching the sample is shown in fig. 6, and the sample still has fracture at the welding seam, which is similar to the performance of the sample without heating treatment, and shows that the heating time is short at this moment, and the performance of the welding seam area is not improved to the level exceeding that of the base material.
Although the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. Therefore, the protection scope of the present invention is subject to the scope defined by the appended claims.
Claims (9)
1. The method for improving the performance of the laser tailor-welded joint of the high-strength steel is characterized by butt-jointing two workpieces and performing laser welding, wherein the two workpieces comprise at least one high-strength steel, the matrix structure of the high-strength steel contains austenite, the thickness of the high-strength steel is less than 3.0mm, and after the workpieces are subjected to laser tailor-welding, the workpieces are subjected to heating treatment at the heating temperature of 100-300 ℃ for 3 seconds-30 minutes.
2. The method for improving the performance of the high-strength steel laser tailor welded joint according to claim 1, wherein the relationship between the heating time T and the heating temperature T is as follows: t is 26342E (-0.029T), wherein T is in units of s and T is in units of C, and the heating time is calculated as the time suitable for achieving the best effect at the corresponding temperature, and the specific time can be adjusted within the range of +/-20% on the basis.
3. The method for improving the performance of a laser tailor-welded joint of high-strength steel according to claim 1, wherein the high-strength steel matrix contains an austenite structure volume fraction of 5% to 40%.
4. The method for improving the performance of the high-strength steel laser tailor welded joint according to claim 1, wherein the tensile strength of the high-strength steel matrix material is greater than 600 MPa.
5. The method of improving the performance of a laser tailor welded joint of high strength steel according to claim 1, wherein said high strength steel substrate is quench and partition steel (Q & P).
6. The method for improving the performance of the laser tailor-welded joint of the high-strength steel according to claim 1, wherein the laser tailor-welding is performed after cooling in an air environment and then heating treatment is performed, and the cooling time is less than 12 hours.
7. The method for improving the performance of the high-strength steel laser tailor-welded joint according to claim 1, wherein the heating process is performed by using a moving mechanism to convey the workpiece into a heating environment, and after the heating time is reached, the workpiece is removed to an air environment to be naturally cooled.
8. The method for improving the performance of the high-strength steel laser tailor-welded joint according to claim 1, wherein the heating treatment means is heating by a liquid medium, immersing the whole workpiece or the welding area in oil or salt in a heating temperature range; the oil is used for conventional heat treatment oil bath, and the salt is used for low-temperature salt bath.
9. The method for improving the performance of the high-strength steel laser tailor-welded joint according to claim 1, wherein the heating treatment means is heating by an air medium, and the workpiece is integrally conveyed to a heating furnace for heating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010720760.5A CN113969343A (en) | 2020-07-24 | 2020-07-24 | Method for improving performance of high-strength steel laser tailor-welded joint |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010720760.5A CN113969343A (en) | 2020-07-24 | 2020-07-24 | Method for improving performance of high-strength steel laser tailor-welded joint |
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| CN113969343A true CN113969343A (en) | 2022-01-25 |
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| CN202010720760.5A Pending CN113969343A (en) | 2020-07-24 | 2020-07-24 | Method for improving performance of high-strength steel laser tailor-welded joint |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2022738C1 (en) * | 1991-04-03 | 1994-11-15 | Центральный научно-исследовательский институт конструкционных материалов "Прометей" | Heterogeneous steel welding method |
| JP2010059451A (en) * | 2008-09-02 | 2010-03-18 | Sumitomo Metal Ind Ltd | Welded joint and manufacturing method therefor |
-
2020
- 2020-07-24 CN CN202010720760.5A patent/CN113969343A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2022738C1 (en) * | 1991-04-03 | 1994-11-15 | Центральный научно-исследовательский институт конструкционных материалов "Прометей" | Heterogeneous steel welding method |
| JP2010059451A (en) * | 2008-09-02 | 2010-03-18 | Sumitomo Metal Ind Ltd | Welded joint and manufacturing method therefor |
Non-Patent Citations (2)
| Title |
|---|
| 王佳佳 等: ""回火工艺对9Ni钢焊接接头显微组织的影响"", 《热加工工艺》 * |
| 肖仁鑫 等: ""退火和激光冲击处理对Q460高强钢焊接接头残余应力及力学性能的影响"", 《热加工工艺》 * |
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Application publication date: 20220125 |
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