Welding process suitable for producing high-performance armor steel welding seam

Abstract

The invention relates to a welding process suitable for producing high-performance armor steel weld joints, which comprises the following steps: (1) 500-grade armor steel is adopted as a base material, and the thickness T of an armor steel plate is 6-8.5 mm; (2) a non-beveled edge type, namely a square beveled edge, is adopted, a square section interlayer of 309S austenitic stainless steel or 2205 duplex stainless steel is placed between the two armored steel plates, and no gap is reserved; and (3) preheating is not carried out before welding, two times of single-pass penetration fusion welding is carried out at the butt joint positions of the two sides of the interlayer and the base metal, specifically, penetration fusion argon arc welding is adopted for welding, the welding current ranges from 450 A to 520 A, the arc voltage ranges from 15 V to 20 V, the welding speed ranges from 28 cm / min to 40 cm / min, the welding heat input ranges from 10 kJ / cm to 22 kJ / cm, and welding is completed through two passes. The armor steel welding joint formed by the invention obtains comprehensive mechanics matched with base metal.

Description

Technical Field

[0001] The present invention relates to a welding process suitable for producing high-performance armor steel welds. Background Art

[0002] Currently, the welding and connection of armored vehicles mainly use traditional fusion welding techniques, such as manual arc welding, flux-cored arc welding, and tungsten inert gas welding. However, due to the ultra-high strength and hardness of armor steel, combined with the residual stress caused during the welding process and the introduced hydrogen element, cold cracks are very likely to occur. In order to prevent the cold crack defects that are extremely easy to form during the welding of armor steel, welding wires with a much lower strength level than the base material are used during the welding of armor steel, such as austenitic stainless steel welding wires and low-hydrogen ferritic welding wires. Although the low matching strength can ensure that no cold cracks occur during the welding of armor steel, the hardness and strength of the weld will be greatly reduced. Such a reduction will not only affect the load-bearing capacity of the armored vehicle, but will also greatly affect the armor-piercing performance of the weld of the armored vehicle, and bullets can easily penetrate through the weld.

[0003] Therefore, it is necessary to specifically develop a technical solution for producing high-performance armor steel welds, so that the welds of armor steel can not only have good crack resistance, but also have high hardness and excellent armor-piercing performance. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention proposes a welding process suitable for producing high-performance armor steel welds. The armor steel welded joint formed by this welding process obtains comprehensive mechanical properties matching those of the base material, and at the same time ensures no cold cracks are generated.

[0005] The technical solution for the present invention to solve the above technical problems is as follows: Provide a welding process suitable for producing high-performance armor steel welds, including the following steps: (1) The base material uses 500-level armor steel, and the thickness T of the armor steel plate is 6 mm - 8.5 mm; (2) Adopt a non-groove type, that is, a square groove, and place a 309S austenitic stainless steel or 2205 duplex stainless steel square-section interlayer between two armor steel plates without leaving a gap; (3) Do not preheat before welding, and perform two single-pass deep penetration weldings from the places where the interlayer is butt-jointed with the base material on both sides, specifically: Use deep penetration argon arc welding for welding, the welding current is 450 A - 520 A, the arc voltage is 15 V - 20 V, the welding speed is 28 cm / min - 40 cm / min, the welding heat input is 10 kJ / cm - 22 kJ / cm, and complete the welding with two passes.

[0006] The further limited technical solution of the present invention is: Preferably, the armor steel in the step (1) comprises the following components by mass fraction: C: ≤0.32%, Mn: ≤0.80%, Si: ≤0.50%, S: ≤0.005%, P: ≤0.025%, Ni: ≤0.50%, Cr: ≤1.2, Mo: ≤0.30%, B: ≤0.002%, and the balance is Fe and inevitable impurities.

[0007] Preferably, the yield strength of the base armor steel is ≥1300 MPa, the tensile strength is ≥1640 MPa, the elongation is ≥10%, and the impact energy KV at -40°C 2 ≥16 J.

[0008] Preferably, the 309S austenitic stainless steel sandwich layer in the step (2) comprises the following components by mass fraction: C: ≤0.08%, Mn: ≤2.0%, Si: ≤1.0%, S: ≤0.03%, P: ≤0.045%, Ni: 12%-15%, Cr: 22%-24%, and the balance is Fe and inevitable impurities.

[0009] Preferably, the 2205 duplex stainless steel sandwich layer in the step (2) comprises the following components by mass fraction: C: ≤0.03%, Mn: ≤2.0%, Si: ≤1.0%, S: ≤0.02%, P: ≤0.03%, Ni: 4.5%-6.5%, Cr: 22%-23%, Mo: 3.0%-3.5%, N: 0.14%-0.20%, and the balance is Fe and inevitable impurities.

[0010] Preferably, after the welding in the step (3) is completed, the weld forms a duplex structure of martensite and austenite, and the impact energy KV of the welded joint at -40°C 2 ≥16 J, the tensile strength of the welded joint is ≥1040 Mpa, the hardness of the weld is ≥450 Hv, the longitudinal surface bend d = 4a of the welded joint is qualified at 180°, and there are no cold crack defects in the weld. Beneficial effects

[0011] The present invention adopts a welding process of deep penetration welding combined with a square-section sandwich layer to perform arc welding on 500-grade armor steel. The impact energy KV2 of the weld at -40°C is ≥16 J, comparable to that of the 500-grade armor steel base material. The tensile strength of the welded joint is ≥1040 Mpa, exceeding 700-800 MPa of the traditional welding process. The hardness of the weld is ≥450 Hv, comparable to that of the 500-grade armor steel base material. The longitudinal surface bend d = 4a of the welded joint is qualified at 180°, and no cold cracks are generated in the weld. The crack resistance is better than that of the same-matching-strength welding wire. The welded joint formed by this welding process has obtained good comprehensive mechanical properties and is suitable for welding 500-grade armor steel with a thickness of 6 mm - 8.5 mm. Description of the drawings

[0012] Figure 1 It is the schematic diagram of the assembly and alignment form before welding and the macroscopic cross-section after welding; Figure 2 It is the actual macroscopic cross-section metallographic diagram after welding is completed. Specific implementation mode Embodiment

[0013] This embodiment provides a welding process applicable to the production of high-performance armor steel welds, including the following steps: The base material uses a 500-level armor steel welding test plate with a yield strength ≥ 1300 MPa, a tensile strength ≥ 1640 MPa, an elongation ≥ 180%, and a -40°C impact energy KV 2 ≥ 16 J, and the size of the test plate is 500 mm (length) × 200 mm (width) × 6 mm (thickness). The square-section sandwich selects 2205 duplex stainless steel, and the size of the sandwich is 500 mm (length) × 10 mm (width) × 6 mm (thickness). This 2205 stainless steel square-section sandwich includes the following components by mass fraction: C: ≤ 0.03%, Mn: ≤ 2.0%, Si: ≤ 1.0%, S: ≤ 0.02%, P: ≤ 0.03%, Ni: 4.5% - 6.5%, Cr: 22% - 23%, Mo: 3.0% - 3.5%, N: 0.14% - 0.20%, and the balance is Fe and unavoidable impurities; The groove type is the I-shaped alignment method without groove opening, without root face, and there is no gap in the groove assembly. Before welding, the square-section sandwich of 2205 duplex stainless steel and the 500-level armor steel base material are spot-welded together; Do not preheat before welding. Before welding, mill the edges and remove dirt from the surfaces of the base material and the sandwich. Use deep penetration argon arc welding, with a welding current of 450 A, an arc voltage of 15 V, a welding speed of 40 cm / min, a welding heat input of 10 kJ / cm, and complete the welding with 2 passes of deep penetration welding. Embodiment

[0014] This embodiment provides a welding process applicable to the production of high-performance armor steel welds, including the following steps: The base material uses a 500-level armor steel welding test plate with a yield strength ≥ 1300 MPa, a tensile strength ≥ 1640 MPa, an elongation ≥ 180%, and a -40°C impact energy KV 2 ≥ 16 J, and the size of the test plate is 500 mm (length) × 200 mm (width) × 8.5 mm (thickness).

[0015] The square-section sandwich is made of 309S austenitic stainless steel, with the sandwich size being 500 mm (length) × 10 mm (width) × 8.5 mm (thickness). The 2205 stainless steel square-section sandwich comprises the following components by weight percentage: C: ≤0.08%, Mn: ≤2.0%, Si: ≤1.0%, S: ≤0.03%, P: ≤0.045%, Ni: 12% - 15%, Cr: 22% - 24%, and the balance is Fe and inevitable impurities; The groove type is the I-shaped butt joint method without groove opening, without root face, and there is no gap in groove assembly. Before welding, the square-section sandwich and the 500-grade armor steel base material are spot welded together; No preheating is required before welding. Before welding, the surfaces of the base material and the sandwich are milled and decontaminated. Deep penetration argon arc welding is used, with a welding current of 520 A, an arc voltage of 20 V, a welding speed of 28 cm / min, and a welding heat input of 22 kJ / cm. The welding is completed with 2 passes of deep penetration welding.

[0016] After welding the 500-grade armor steel by the welding method of the above Examples 1 - 2, the mechanical properties of the welded joint are detected. The hardness, impact, tensile, and bending properties of the welded joint are shown in Table 1 and Table 2: Table 1: Impact performance table of the welded joint Table 2: Tensile and side bend performance table of the welded joint It can be seen that the comprehensive mechanical properties of the welded joints obtained in Examples 1 - 2 are excellent. The impact energy KV of the weld at -40 °C 2 ≥16 J, the tensile strength Rm: ≥1040 MPa, the weld hardness ≥450 Hv, and the longitudinal surface bend of the welded joint d = 4a, 180° is qualified. Moreover, the process implementation method provided by this patent is simple and highly applicable.

[0017] In addition to the above embodiments, the present invention may have other implementation manners. Any technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. A welding process suitable for producing high performance armor steel welds, characterized in that: The following steps are involved: (1) The base material is 500 grade armor steel, and the thickness T of the armor steel plate is 6mm-8.5mm; (2) A square groove is used, in which a square cross-section interlayer of 309S austenitic stainless steel or 2205 duplex stainless steel is placed between two armor plates without leaving any gap; (3) Without preheating before welding, two single-pass deep penetration welding is performed from the place where the two sides of the interlayer are connected to the base material. Specifically, deep penetration argon arc welding is used for welding, the welding current is 450A-520A, the arc voltage is 15V-20V, the welding speed is 28cm / min-40cm / min, the welding heat input is 10kJ / cm-22kJ / cm, and the welding is completed in two passes.

2. A welding process suitable for producing high-performance armor steel welds according to claim 1, characterized in that: The armor steel in step (1) comprises the following components by mass fraction: C: ≤0.32%, Mn: ≤0.80%, Si: ≤0.50%, S: ≤0.005%, P: ≤0.025%, Ni: ≤0.50%, Cr: ≤1.2, Mo: ≤0.30%, B: ≤0.002%, the balance is Fe and unavoidable impurities.

3. A welding process suitable for producing high-performance armor steel welds according to claim 1, characterized in that: The yield strength of the parent armor steel is ≥1300MPa, the tensile strength is ≥1640MPa, the elongation is ≥10%, and the impact energy KV2 at -40°C is ≥16J.

4. A welding process suitable for producing high-performance armor steel welds according to claim 1, characterized in that: In step (2), the 309S austenitic stainless steel interlayer comprises the following components by mass fraction: C: ≤0.08%, Mn: ≤2.0%, Si: ≤1.0%, S: ≤0.03%, P: ≤0.045%, Ni: 12%-15%, Cr: 22%-24%, the balance is Fe and unavoidable impurities.

5. A welding process suitable for producing high-performance armor steel welds according to claim 1, characterized in that: The 2205 duplex stainless steel interlayer in step (2) comprises the following components by mass fraction: C: ≤0.03%, Mn: ≤2.0%, Si: ≤1.0%, S: ≤0.02%, P: ≤0.03%, Ni: 4.5%-6.5%, Cr: 22%-23%, Mo: 3.0%-3.5%, N: 0.14%~0.20%, the balance is Fe and unavoidable impurities.

6. A welding process suitable for producing high-performance armor steel welds according to claim 1, characterized in that: After the welding in step (3) is completed, the weld forms a dual-phase structure of martensite and austenite, the low-temperature impact energy of the weld joint at -40°C KV2≥16J, the tensile strength of the weld joint≥1040Mpa, the weld hardness≥450Hv, the longitudinal surface bending d=4a of the weld joint, 180° is qualified, and the weld has no cold crack defects.

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