DIFFERENT-STRENGTH STEEL WELDING COMPONENT WITH ALUMINUM OR ALUMINUM-ALLOY PLATING AND METHOD FOR MANUFACTURING SAME

Abstract

Disclosed is a different-strength steel welding component with an aluminum or aluminum-alloy plating formed by means of butt welding of a high-strength steel plate and a low-strength steel plate, and each of the high-strength steel plate and the low-strength steel plate comprises a base body and at least one pure aluminum or aluminum-alloy plating on a surface of the base body. The tensile strength of a welding seam of the welding component after hot stamping is greater than the tensile strength of a low-strength steel base metal, and the elongation is greater than 4%, such that application requirements of the welding component in the field of automobile hot stamping are met. The present disclosure also relates to a method for manufacturing a different-strength steel welding component with an aluminum or aluminum-alloy plating and a welding wire used in the method.

Claims

1. A method for manufacturing a differential-strength steel welded component with an aluminum or aluminum alloy clad layer, comprising the following steps: 1) Taking two straight steel plates for use as steel plates to be welded, wherein the steel plate to be welded comprises a substrate and at least one clad layer on a surface thereof, wherein the clad layer comprises an intermetallic compound alloy layer in contact with the substrate and a metal alloy layer thereon, wherein the clad layer in a to-be-welded zone of the steel plate to be welded is not removed or thinned; wherein the two steel plates to be welded are a high-strength steel plate and a low-strength steel plate respectively, wherein the high-strength steel plate has a tensile strength of from 1300 MPa to 1700 MPa after hot stamping, and the low-strength steel plate has a tensile strength of from 400 MPa to 700 MPa after hot stamping; 2) Presetting a butt gap between the two steel plates to be welded at 0.2-0.5 mm; 3) Integrating the two steel plates to be welded by welding using a laser filler wire welding process or a gas shielded welding process, wherein the laser filler wire welding process uses a laser spot having a diameter of from 1.2 mm to 2.0 mm, a defocus distance of from −3 mm to 0 mm, a laser power controlled at from 4 kW to 6 kW, a welding speed controlled at from 40 mm/s to 120 mm/s, a welding wire having a diameter of from 0.8 mm to 1.4 mm, and a wire feeding speed of from 50 mm/s to 100 mm/s; wherein 99.99% high-purity argon with a flow rate of 10-25 L/min is used as a shielding gas; wherein a gas feeding pipe is 60-120 degrees relative to a welding direction and delivers the shielding gas uniformly and stably to a welding area; the gas shielded welding process is a gas metal arc welding process; wherein, preferably, the gas metal arc welding process uses a welding current of 110-130 A, a welding voltage of 18-25 V, a welding speed of 300-800 mm/min, a welding wire having a diameter of 0.8-1.4 mm, wherein 60-80% argon+20-40% carbon dioxide with a flow rate of 10-25 L/min is used as a shielding gas; wherein a gas feeding direction is 60-120 degrees relative to a welding direction.

2. The method for manufacturing a differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 1, wherein the substrate of the high-strength steel plate has a composition based on weight percentage of C: 0.08-0.8%, Si: 0.05-1.0%, Mn: 0.1-5%, P<0.3%, S<0.1%, Al<0.3%, Ti<0.5%, B: 0.0005-0.1%, Cr: 0.01-3%, and a balance of Fe and other unavoidable impurities.

3. The method for manufacturing a differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 1, wherein the substrate of the high-strength steel plate has a composition based on weight percentage of C: 0.1-0.6%, Si: 0.07-0.7%, Mn: 0.3-4%, P<0.2%, S<0.08%, Al<0.2%, Ti<0.4%, B: 0.0005-0.08%, Cr: 0.01-2%, and a balance of Fe and other unavoidable impurities.

4. The method for manufacturing a differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 1, wherein the substrate of the high-strength steel plate has a composition based on weight percentage of C: 0.15-0.5%, Si: 0.1-0.5%, Mn: 0.5-3%, P<0.1%, S<0.05%, Al<0.1%, Ti<0.2%, B: 0.0005-0.08%, Cr: 0.01-1%, and a balance of Fe and other unavoidable impurities.

5. The method for manufacturing a differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 1, wherein the substrate of the low-strength steel plate has a composition based on weight percentage of C: 0.03-0.1%, Si: 0-0.3%, Mn: 0.5-2.0%, P<0.03%, S<0.01%, Al<0.1%, Cr: 0-0.1%, Ti: 0-0.05%, and a balance of Fe and other unavoidable impurities.

6. The method for manufacturing a differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 1, wherein the clad layer is pure aluminum or aluminum alloy, wherein the aluminum alloy has a composition based on weight percentage of Si: 5-11%, Fe: 0-4%, and a balance of Al.

7. The method for manufacturing a differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 1, wherein the substrate of each of the high-strength steel plate and the low-strength steel plate has a thickness of 0.5-3 mm.

8. The method for manufacturing a differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 1, wherein the welding wire has a composition based on weight percentage of C 0.1-0.25%, Si 0.2-0.4%, Mn 1.2-2%, P<0.03%, S<0.006%, Al<0.06%, Ti 0.02-0.08%, Cr 0.05-0.2%, and a balance of Fe and unavoidable impurities; wherein the welding wire has a diameter of 0.8-1.4 mm.

9. A differential-strength steel welded component with an aluminum or aluminum alloy clad layer manufactured by the method of claim 1.

10. A differential-strength steel welded component with an aluminum or aluminum alloy clad layer, formed by butt welding of a high-strength steel plate and a low-strength steel plate, wherein the high-strength steel plate has a tensile strength of 1300-1700 MPa after hot stamping, and the low-strength steel plate has a tensile strength of 400-700 MPa after hot stamping; wherein the high-strength steel plate and the low-strength steel plate each comprise a substrate and at least one pure aluminum or aluminum alloy clad layer on a surface thereof; wherein the clad layer comprises an intermetallic compound alloy layer in contact with the substrate and a metal alloy layer thereon; wherein the substrate of the high-strength steel plate has a composition based on weight percentage of C: 0.08-0.8%, Si: 0.05-1.0%, Mn: 0.1-5%, P<0.3%, S<0.1%, Al<0.3%, Ti<0.5%, B: 0.0005-0.1%, Cr: 0.01-3%, and a balance of Fe and unavoidable impurities; wherein the substrate of the low-strength steel plate has a composition based on weight percentage of C: 0.03-0.1%, Si: 0-0.3%, Mn: 0.5-2.0%, P<0.03%, S<0.01%, Al<0.1%, Cr: 0-0.1%, Ti: 0-0.05%, and a balance of Fe and unavoidable impurities; wherein a welding wire used to weld the high-strength steel plate and the low-strength steel plate has a composition based on weight percentage of C 0.1-0.25%, Si 0.2-0.4%, Mn 1.2-2%, P<0.03%, S<0.006%, Al<0.06%, Ti 0.02-0.08%, Cr 0.05-0.2%, and a balance of Fe and unavoidable impurities; wherein the welding wire has a diameter of 0.8-1.4 mm.

11. The differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 10, wherein a welding line of the differential-strength steel welded component has a tensile strength that is greater than the strength of the low-strength steel base material; when a welding joint is fractured under a tensile load, the fracture occurs in the low-strength steel base material; and the welding joint has an elongation of greater than 4%.

12. The differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 10, wherein the substrate of the high-strength steel plate has a composition based on weight percentage of C: 0.1-0.6%, Si: 0.07-0.7%, Mn: 0.3-4%, P<0.2%, S<0.08%, Al<0.2%, Ti<0.4%, B: 0.0005-0.08%, Cr: 0.01-2%, and a balance of Fe and unavoidable impurities.

13. The differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 10, wherein the substrate of the low-strength steel plate has a composition based on weight percentage of C: 0.06-0.1%, Si: 0.06-0.2%, Mn: 0.5-1.5%, P<0.1%, S<0.05%, Al: 0.02-0.08%, Cr: 0.02-0.1%, Ti: 0.002-0.045%, and a balance of Fe and other unavoidable impurities.

14. The differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 9, wherein the differential-strength steel welded component is an A-pillar, a B-pillar or a center tunnel of an automobile.

15. A welding wire for use in the method for manufacturing a differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 1, wherein the welding wire has a composition based on weight percentage of C 0.1-0.25%, Si 0.2-0.4%, Mn 1.2-2%, P<0.03%, S<0.006%, Al<0.06%, Ti 0.02-0.08%, Cr 0.05-0.2%, and a balance of Fe and unavoidable impurities; wherein the welding wire has a diameter of 0.8-1.4 mm.

16. The differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 12, wherein the substrate of the high-strength steel plate has a composition based on weight percentage of C: 0.1-0.6%, Si: 0.07-0.7%, Mn: 0.3-4%, P<0.2%, S<0.08%, Al: 0.04-0.1%, Ti: 0.01-0.3%, B: 0.0005-0.08%, Cr: 0.1-1.0%, and a balance of Fe and unavoidable impurities.

17. The differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 12, wherein the substrate of the high-strength steel plate has a composition based on weight percentage of C: 0.15-0.5%, Si: 0.1-0.5%, Mn: 0.5-3%, P<0.1%, S<0.05%, Al: 0.04-0.09%, Ti: 0.02-0.2%, B: 0.003-0.08%, Cr: 0.1-0.8%, and a balance of Fe and unavoidable impurities.

18. The differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 10, wherein the substrate of the low-strength steel plate has a composition based on weight percentage of C: 0.06-0.1%, Si: 0.06-0.2%, Mn: 0.5-1.5%, P<0.03%, S<0.005%, Al: 0.02-0.08%, Cr: 0.02-0.1%, Ti: 0.002-0.045%, and a balance of Fe and other unavoidable impurities.

19. The differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 10, wherein the differential-strength steel welded component is an A-pillar, a B-pillar or a center tunnel of an automobile.

20. The differential-strength steel welded component with an aluminum or aluminum alloy clad layer according to claim 10, wherein the clad layer is an aluminum alloy and the aluminum alloy has a composition based on weight percentage of Si: 5-11%, Fe: 0-4%, and a balance of Al.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] FIG. 1 shows tensile curves of the welding joints in the Examples according to the present disclosure.

[0063] FIG. 2 shows the samples in which the welding joints fractured under tension in the Examples according to the present disclosure.

[0064] FIG. 3 is a metallographic diagram of a welding joint in Example 1 according to the present disclosure.

[0065] FIG. 4 is a metallographic diagram of a welding joint in Example 2 according to the present disclosure.

[0066] FIG. 5 is a metallographic diagram of a welding joint in Example 3 according to the present disclosure.

[0067] FIG. 6 shows the hardness distribution of the welding joint in Example 1 according to the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0068] The disclosure will be further illustrated with reference to the following Examples and accompanying drawings.

Example 1

[0069] A high-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.75 mm) and a low-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.8 mm) were used for tailor welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.3 mm. The welding wire developed by the invention was used. A laser power of 4.5 kW, a spot diameter of 2 mm, a defocus distance of −2 mm, a welding speed of 80 mm/s, a welding wire diameter of 1.2 mm, and a wire feeding speed of 70 mm/s were employed. The composition of the welding wire is shown in Table 3. High-purity argon was used as a shielding gas. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 120 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 930° C. for 4 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4; the tensile curve of the welding joint is shown in FIG. 1; the fractured position is shown in FIG. 2; the metallographic phase of the joint is shown in FIG. 3; and the hardness of the joint is shown in FIG. 6.

Example 2

[0070] A high-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.8 mm) and a low-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.8 mm) were used for welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.4 mm. The welding wire developed by the invention was used. A laser power of 4.5 kW, a spot diameter of 2 mm, a defocus distance of −3 m, a welding speed of 80 mm/s, a welding wire diameter of 1.2 mm, and a wire feeding speed of 80 mm/s were employed. The composition of the welding wire is shown in Table 3. High-purity argon was used as a shielding gas. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 60 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 930° C. for 4 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4; the tensile curve of the welding joint is shown in FIG. 1; the fractured position is shown in FIG. 2; and the metallographic phase of the joint is shown in FIG. 4.

Example 3

[0071] A high-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.5 mm) and a low-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.5 mm) were used for welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.25 mm. The welding wire developed by the invention was used. A laser power of 4 kW, a spot diameter of 2 mm, a defocus distance of −1 mm, a welding speed of 60 mm/s, a welding wire diameter of 1.2 mm, and a wire feeding speed of 60 mm/s were employed. The composition of the welding wire is shown in Table 3. High-purity argon was used as a shielding gas. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 120 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 930° C. for 4 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4; the tensile curve of the welding joint is shown in FIG. 1; the fractured position is shown in FIG. 2; and the metallographic phase of the joint is shown in FIG. 5.

Example 4

[0072] A high-strength hot formed steel plate with no clad layer (t=1.4 mm) and a low-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.8 mm) were used for tailor welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.3 mm. The welding wire developed by the invention was used. A laser power of 4.5 kW, a spot diameter of 2 mm, a defocus distance of −2 mm, a welding speed of 80 mm/s, a welding wire diameter of 1.2 mm, and a wire feeding speed of 70 mm/s were employed. The composition of the welding wire is shown in Table 3. High-purity argon was used as a shielding gas. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 90 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 950° C. for 3 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4.

Example 5

[0073] A high-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.2 mm) and a low-strength hot formed steel plate with no clad layer (t=1.4 mm) were used for tailor welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.3 mm. The welding wire developed by the invention was used. A laser power of 4.5 kW, a spot diameter of 1.4 mm, a defocus distance of −1 mm, a welding speed of 75 mm/s, a welding wire diameter of 1.0 mm, and a wire feeding speed of 100 mm/s were employed. The composition of the welding wire is shown in Table 3. High-purity argon was used as a shielding gas. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 90 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 950° C. for 3 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4.

Example 6

[0074] A high-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.75 mm) and a low-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.4 mm) were used for tailor welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.3 mm. The welding wire developed by the invention was used. A laser power of 5.5 kW, a spot diameter of 1.4 mm, a defocus distance of −2 mm, a welding speed of 120 mm/s, a welding wire diameter of 1.2 mm, and a wire feeding speed of 70 mm/s were employed. The composition of the welding wire is shown in Table 3. High-purity argon was used as a shielding gas. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 90 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 950° C. for 3 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4.

Example 7

[0075] A high-strength hot formed steel plate with no clad layer (t=1.8 mm) and a low-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.4 mm) were used for tailor welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.3 mm. The welding wire developed by the invention was used. A laser power of 4.5 kW, a spot diameter of 2 mm, a defocus distance of −2 mm, a welding speed of 100 mm/s, a welding wire diameter of 1.2 mm, and a wire feeding speed of 50 mm/s were employed. The composition of the welding wire is shown in Table 3. High-purity argon was used as a shielding gas. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 90 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 950° C. for 3 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4.

Example 8

[0076] A high-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.5 mm) and a low-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.4 mm) were used for tailor welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.3 mm. The welding wire developed by the invention was used. A laser power of 4.5 kW, a spot diameter of 2.0 mm, a defocus distance of −1 mm, a welding speed of 80 mm/s, a welding wire diameter of 1.2 mm, and a wire feeding speed of 80 mm/s were employed. The composition of the welding wire is shown in Table 3. High-purity argon was used as a shielding gas. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 90 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 950° C. for 3 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4.

Example 9

[0077] A high-strength hot formed steel plate with no clad layer (t=1.4 mm) and a low-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.2 mm) were used for tailor welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.3 mm. The welding wire developed by the invention was used. A laser power of 5 kW, a spot diameter of 2 mm, a defocus distance of −1 mm, a welding speed of 120 mm/s, a welding wire diameter of 1.2 mm, and a wire feeding speed of 50 mm/s were employed. The composition of the welding wire is shown in Table 3. High-purity argon was used as a shielding gas. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 90 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 950° C. for 2.5 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4.

Example 10

[0078] A high-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.2 mm) and a low-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.8 mm) were used for tailor welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.3 mm. The welding wire developed by the invention was used. A laser power of 4.5 kW, a spot diameter of 1.4 mm, a defocus distance of −1 mm, a welding speed of 80 mm/s, a welding wire diameter of 1.0 mm, and a wire feeding speed of 100 mm/s were employed. The composition of the welding wire is shown in Table 3. High-purity argon was used as a shielding gas. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 90 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 950° C. for 4 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4.

Example 11

[0079] A high-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.2 mm) and a low-strength hot formed steel plate with an aluminum-silicon clad layer (t=1.8 mm), which were the same as those used in Example 10, were used for tailor welding. The chemical compositions of the plates are shown in Tables 1 and 2. The steel plates were flat, and their surfaces were clean and free of oil and water stains. The to-be-welded edges of the high-strength and low-strength blanks were prepared by laser cutting. Before welding, the butt gap was preset at 0.3 mm. The same welding wire as that used in Example 10 was used. A welding current of 120 A, a welding voltage of 22 V, a welding speed of 500 mm/min, a preset gap of 0.5 mm between the plates to be tailor welded, and a welding wire diameter of 1.0 mm were employed. The shielding gas was 80% argon+20% carbon dioxide. The gas flow rate was 15 L/min. The gas feeding direction was at an angle of 90 degrees relative to the welding direction. After tailor welded using the welding process described above, the blanks were heated at 950° C. for 4 minutes and cooled in a water-passing mold for 10 seconds. The mechanical properties of the welding joint are shown in Table 4.

TABLE-US-00001 TABLE 1 High-strength steel plate composition weight percentage (wt %) Ex. C Si Mn P S Al Ti B Cr 1 0.15 0.10 2.90 0.059 0.038 0.09 0.090 0.0031 0.15 2 0.25 0.23 1.19 0.015 0.001 0.04 0.030 0.0040 0.27 3 0.49 0.50 2.51 0.024 0.04 0.08 0.027 0.0052 0.51 4 0.39 0.36 3.00 0.044 0.03 0.07 0.05 0.0062 0.71 5 0.50 0.48 0.50 0.081 0.02 0.05 0.20 0.0071 0.20 6 0.15 0.10 2.90 0.059 0.038 0.09 0.090 0.0031 0.15 7 0.25 0.23 1.19 0.015 0.001 0.04 0.030 0.0040 0.27 8 0.49 0.50 2.51 0.024 0.04 0.08 0.027 0.0052 0.51 9 0.39 0.36 3.00 0.044 0.03 0.07 0.05 0.0062 0.71 10 0.50 0.48 0.50 0.081 0.02 0.05 0.20 0.0071 0.20

TABLE-US-00002 TABLE 2 Low-strength steel plate composition weight percentage (wt %) Ex. C Si Mn P S Al Cr Ti 1 0.073 0.079 1.42 0.011 0.0018 0.031 0.076 0.002 2 0.06 0.199 0.76 0.015 0.004 0.046 0.028 0.004 3 0.065 0.185 0.81 0.024 0.005 0.071 0.051 0.007 4 0.095 0.065 0.5 0.01 0.001 0.053 0.095 0.045 5 0.073 0.079 1.42 0.011 0.0018 0.031 0.076 0.002 6 0.06 0.199 0.76 0.015 0.004 0.046 0.028 0.004 7 0.065 0.185 0.81 0.024 0.005 0.071 0.051 0.007 8 0.095 0.065 0.5 0.01 0.001 0.053 0.095 0.045 9 0.06 0.199 0.76 0.015 0.004 0.046 0.028 0.004 10 0.065 0.185 0.81 0.024 0.005 0.071 0.051 0.007

TABLE-US-00003 TABLE 3 Welding wire composition weight percentage (wt %) Ex. C Si Mn P S Al Cr Ti 1 0.22 0.25 1.24 0.0087 0.002 0.0454 0.169 0.028 2 0.15 0.35 1.87 0.008 0.0018 0.0367 0.105 0.075 3 0.18 0.39 1.53 0.024 0.0010 0.057 0.082 0.051 4 0.12 0.29 1.67 0.03 0.0012 0.045 0.189 0.067 5 0.19 0.21 1.78 0.0062 0.005 0.030 0.052 0.058 6 0.22 0.25 1.24 0.0087 0.002 0.0454 0.169 0.028 7 0.15 0.35 1.87 0.008 0.0018 0.0367 0.105 0.075 8 0.18 0.39 1.53 0.024 0.0010 0.057 0.082 0.051 9 0.12 0.29 1.67 0.03 0.0012 0.045 0.189 0.067 10 0.19 0.21 1.78 0.0062 0.005 0.030 0.052 0.058

TABLE-US-00004 TABLE 4 Mechanical properties of tailor welded plates after hot stamping Tensile Tensile strength strength of high- of low- strength strength steel base steel base Joint Joint material material elongation corrosion Ex. (MPa) (MPa) (%) Fracture position resistance** 1 1451 677 12.2 Low-strength steel Passed base material 2 1531 570 10.7 Low-strength steel Passed base material 3 1357 550 11.4 Low-strength steel Passed base material 4 1589 643 11.5 Low-strength steel Passed base material 5 1675 675 12.7 Low-strength steel Passed base material 6 1470 563 9.6 Low-strength steel Passed base material 7 1527 541 10.2 Low-strength steel Passed base material 8 1384 633 11.8 Low-strength steel Passed base material 9 1540 568 11.7 Low-strength steel Passed base material 10 1648 545 12.3 Low-strength steel Passed base material 11 1630 554 11.7 Low-strength steel Passed base material *Standard tensile samples having a nominal width of 12.5 mm and an original gauge length of 50 mm were used to measure the tensile strength and elongation; **The corrosion resistance test was performed according to DIN50021, DIN50017, and DIN50014 standards.