A gas shielded welding wire and welding method for welding E47BCA and E47

Abstract

The invention discloses a gas shielded welding wire for welding E47BCA and E47 and a welding method, wherein the chemical composition and mass percentage of the gas shielded welding wire are: C≤0.05%, Si≤0.40%, 1.3%≤Mn≤1.5%, 1.5%≤Ni≤2.5%, 1.5%≤Cu≤2.0%, 0.5%≤Ti≤1.0%, 2.0%≤Mo≤2.5%, P≤0.015%, S≤0.015%, and the balance is Fe; the welding method adopts a low preheating temperature of 80 DEG C and a high welding speed; the gas shielded welding wire cladding metal of the invention has excellent mechanical properties and good corrosion resistance; the welding parameters adopted by the method cooperate with the groove form and the gas shielded welding wire, reduce the preheating temperature, reduce the filling amount, significantly improve the production efficiency, reduce the cost, reduce the occurrence of welding defects, and have extremely high protection for the performance of the welding heat affected zone, effectively ensuring the crack arrest performance of the welding joint.

Description

Technical Field

[0001] The invention relates to a gas shielded welding wire and a welding method for welding crack arrest steel and ordinary ship plates, and in particular to a gas shielded welding wire and a welding method for welding E47BCA and E47. Background Art

[0002] In the actual application of container ship production, there is not only welding between crack arrest steel and crack arrest steel, but also welding between some crack arrest steel and ordinary ship plates. When welding E47BCA and E47, two steels with different compositions and processes, the transition of weld metal and the strength and low-temperature toughness of the weld after welding cannot be effectively guaranteed. In addition, the control of current, voltage, welding speed and preheating temperature during the welding process is relatively strict, which increases the cost of construction and production. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a gas shielded welding wire suitable for welding E47BCA and E47 and capable of improving the tensile strength of the welded joint. Another purpose of the present invention is to provide a welding method for the above-mentioned gas shielded welding wire.

[0004] Technical solution: The gas shielded welding wire for welding E47BCA and E47 described in the present invention has the following chemical compositions and mass percentages: C≤0.05%, Si≤0.40%, 1.3%≤Mn≤1.5%, 1.5%≤Ni≤2.5%, 1.5%≤Cu≤2.0%, 0.5%≤Ti≤1.0%, 2.0%≤Mo≤2.5%, P≤0.015%, S≤0.015%, and the remainder is Fe. The mechanical properties of the cladding metal are as follows: tensile strength is 625MPa, yield strength is 540MPa; impact energy Akv at -40°C is: 111J, 108J, 114J.

[0005] The C content has a great influence on the strength and toughness of the weld. When the C content is low, the weld strength is low, the ferrite proportion increases, and the weld toughness improves; when the C content is high, the weld strength is high, the pearlite proportion increases, and the weld toughness decreases.

[0006] Mn can play a deoxidizing role, which can prevent the formation of iron carbide inclusions that cause hot cracks, promote the refinement of ferrite grains and carbides, and thus improve the strength and toughness of the weld.

[0007] Ti can react with N in austenite to form TiN particles. TiN has a very low solubility and will form very fine dispersions in the weld, which can effectively prevent grain growth and become the nucleation core of acicular ferrite, thereby greatly improving the toughness of the weld.

[0008] Mo is a strong solid solution strengthening element. It can improve the strength of the weld and delay the transformation temperature of austenite to inhibit the formation of proeutectoid ferrite and side plate ferrite, and promote the formation of intracrystalline acicular ferrite, thereby improving the low-temperature toughness of the weld. In addition, Mo will inhibit the reduction in strength during reheating caused by subsequent welds during multi-layer and multi-pass welding, and also has an inhibitory effect on the deterioration of toughness. Since large structures use thick plates, welding is performed by multi-layer and multi-pass welding in this case. In multi-layer and multi-pass welding, the weld metal formed in the weld before the subsequent weld will be reheated by the subsequent welding weld, so the weld metal formed in the previous weld will soften. The strength range of the weld metal can be adjusted by controlling the Mo content.

[0009] Cu is an important metal element that improves corrosion resistance.

[0010] Ni is added to the weld metal as a strengthening element to improve the strength of the weld metal through grain refinement and solid solution strengthening. At the same time, its addition can also reduce the toughness-brittleness transition temperature of the weld metal. In addition, the Ni element has good corrosion resistance to acids.

[0011] A welding method for welding E47BCA and E47 using the above-mentioned gas shielded welding wire comprises the following steps:

[0012] (1) The butt joint groove adopts a symmetrical V-shaped groove with a groove angle of 40°±2°, a groove gap of 8mm, and a pad on the back;

[0013] (2) Remove the oil and rust stains on both sides of the weld of E47BCA steel plate and E47 steel plate, so that both sides of the weld are in a pollution-free state before welding;

[0014] (3) The preheating temperature is 80°C, and the interlayer temperature is kept below 200°C;

[0015] (4) Perform base welding: base welding current 160-170A, arc voltage 24-25V, welding speed 10-11cm / min;

[0016] (5) Performing filling welding: the welding current of the filling welding is 190-200A, the arc voltage is 24-25V, and the welding speed is 18-19cm / min;

[0017] (6) Perform cover welding: The welding current of cover welding is 190-200A, the arc voltage is 24-25V, and the welding speed is 16-17cm / min.

[0018] Furthermore, the protective gas is pure CO 2 .

[0019] Furthermore, the welding current is direct current.

[0020] Furthermore, the liner is a ceramic liner.

[0021] Furthermore, the base welding in step (4) adopts a single-sided welding and double-sided forming welding technique.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0023] 1. The gas shielded welding wire of the present invention has excellent mechanical properties and good corrosion resistance;

[0024] 2. The welding parameters adopted by this method are matched with the groove form and gas shielded welding wire, which reduces the preheating temperature, reduces the filling amount, significantly improves the production efficiency and reduces the cost;

[0025] 3. The welding wire and welding method adopted in the present invention reduce the occurrence of welding defects, and have extremely high protection for the performance of the welding heat affected zone, effectively ensuring the crack arrest performance of the welded joint. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below.

[0027] The ship plate crack arrest steel is a 90mm thick E47BCA steel plate, and its chemical composition is: C: 0.045, Mn: 1.60, Ni: 0.35, Nb: 0.005%, Ti: 0.005%, Al: 0.015%, Cr: 0.015%, Cu: 0.10%, Si: 0.16%, P: 0.008%, S: 0.004%, and the balance is Fe and other inevitable impurities. The mechanical properties of the E47BCA1 steel plate are: tensile strength is 580MPa, yield strength is 470MPa; impact energy Akv at -40°C is: 134J, 122J, 124J.

[0028] The non-crack arresting common ship plate is a 90 mm thick E47 steel plate, and the chemical composition of the E47 steel plate is: C: 0.06%, Si: 0.60%, Mn: 1.55%, Cr: 0.2%, Ni: 0.15%, P: 0.015%, S: 0.005%. The mechanical properties of the E47 steel plate are: tensile strength of 540MPa, yield strength of 430MPa, and impact energy Akv of 120, 112, and 118 at -40°C.

[0029] Example 1

[0030] The diameter of the gas shielded welding wire used in welding E47BCA steel and E47 steel in this embodiment is Φ1.2 mm. The composition of the gas shielded welding wire is shown in Table 1. The shielding gas is pure CO 2 , the welding method is as follows:

[0031] (1) The welding groove is prepared by carbon arc gouging. The groove type is a symmetrical V-shaped groove with a groove angle of 40°, an installation gap of 8 mm, no blunt edge is reserved, and a ceramic liner is installed on the back. The welding technique adopts single-sided welding and double-sided forming;

[0032] (2) E47BCA steel plate and E47 steel plate need to use a grinder or other grinding methods to remove oil and rust stains on both sides of the weld, so that both sides of the weld are in a pollution-free state before welding;

[0033] (3) The preheating temperature is 80°C, and the interlayer temperature is kept below 200°C;

[0034] (4) When laying the base: welding current is 165A; arc voltage is 24V; welding speed is 9cm / min;

[0035] (5) During filling: welding current is 195A; arc voltage is 24V; welding speed is 18cm / min;

[0036] (6) When covering: welding current is 195A; arc voltage is 24V; welding speed is 16cm / min.

[0037] Analysis of the microstructure and mechanical properties of the metal after welding in this embodiment: The weld metal structure is austenite + ferrite. After testing, no solidification cracks and reheating cracks were generated. The mechanical properties of the completed welding are shown in Table 2.

[0038] Example 2

[0039] The composition of the welding wire used in Example 2 is shown in Table 1. The welding method is basically the same as that in Example 1, except that the process parameters used are different, which are as follows: when making the base: the welding current is 170A; the arc voltage is 24V; the welding speed is 8.5cm / min; when filling: the welding current is 205A; the arc voltage is 24V; the welding speed is 17cm / min; when covering: the welding current is 205A; the arc voltage is 24V; the welding speed is 15cm / min.

[0040] Analysis of the microstructure and mechanical properties of the metal after welding in this embodiment: The weld metal structure is austenite + ferrite. After testing, no solidification cracks and reheating cracks are generated; the mechanical properties of the completed welding are shown in Table 2.

[0041] Example 3

[0042] The composition of the welding wire used in Example 3 is shown in Table 1. The welding method is basically the same as that in Example 1, except that the process parameters used are different, which are as follows: when making the base: the welding current is 170A; the arc voltage is 24V; the welding speed is 8.7cm / min; when filling: the welding current is 200A; the arc voltage is 24V; the welding speed is 17.3cm / min; when covering: the welding current is 200A; the arc voltage is 24V; the welding speed is 15.3cm / min.

[0043] Analysis of the microstructure and mechanical properties of the metal after welding in this embodiment: The weld metal structure is austenite + ferrite. After testing, no solidification cracks and reheating cracks are generated; the mechanical properties of the completed welding are shown in Table 2.

[0044] Example 4

[0045] The composition of the welding wire used in Example 4 is shown in Table 1. The welding method is basically the same as that in Example 1, except that the process parameters used are different, which are as follows: when making the base: the welding current is 170A; the arc voltage is 24V; the welding speed is 10.6cm / min; when filling: the welding current is 190A; the arc voltage is 25V; the welding speed is 18.2cm / min; when covering: the welding current is 200A; the arc voltage is 24V; the welding speed is 16.5cm / min.

[0046] Analysis of the microstructure and mechanical properties of the metal after welding in this embodiment: The weld metal structure is austenite + ferrite. After testing, no solidification cracks and reheating cracks are generated; the mechanical properties of the completed welding are shown in Table 2.

[0047] Example 5

[0048] The composition of the welding wire used in Example 5 is shown in Table 1. The welding method is basically the same as that in Example 1, except that the process parameters used are different, which are as follows: when making the base: the welding current is 170A; the arc voltage is 24V; the welding speed is 10.7cm / min; when filling: the welding current is 200A; the arc voltage is 24V; the welding speed is 18.8cm / min; when covering: the welding current is 200A; the arc voltage is 24V; the welding speed is 17cm / min.

[0049] Analysis of the microstructure and mechanical properties of the metal after welding in this embodiment: The weld metal structure is austenite + ferrite. After testing, no solidification cracks and reheating cracks are generated; the mechanical properties of the completed welding are shown in Table 2.

[0050] The main chemical components and mass percentages of the gas shielded welding wires of Examples 1-5 are shown in Table 1 below, with the remainder being iron.

[0051] Example C Si Mn Ni Cu Ti Mo P S Example 1 0.05 0.39 1.40 1.63 1.74 0.53 2.11 0.010 0.010 Example 2 0.05 0.37 1.35 1.89 1.69 0.65 2.08 0.009 0.010 Example 3 0.04 0.38 1.37 2.02 1.73 0.51 2.13 0.010 0.010 Example 4 0.05 0.33 1.45 2.22 1.89 0.77 2.32 0.010 0.010 Example 5 0.05 0.38 1.31 2.39 1.93 0.81 2.45 0.010 0.010

[0052] Table 1

[0053] The performance of the E47BCA and E47 welded joints obtained by the above method is shown in Table 2; wherein WM refers to the molten metal of the gas shielded welding wire (i.e. the weld); HAZ refers to the heat affected zone, which is 2mm outside the fusion line; FL refers to the fusion line.

[0054]

[0055]

[0056] Table 2.

Claims

1. A welding method for gas shielded welding wire for welding E47BCA steel plate and E47 steel plate, characterized in that: The chemical composition and mass percentage of the gas shielded welding wire are: C≤0.05%, Si≤0.40%, 1.3%≤Mn≤1.5%, 1.5%≤Ni≤2.5%, 1.5%≤Cu≤2.0%, 0.5%≤Ti≤1.0%, 2.0%≤Mo≤2.5%, P≤0.015%, S≤0.015%, and the balance is Fe; the chemical composition of the E47BCA steel plate is: C: 0.045%, Mn: 1.60%, Ni: 0.35%, Nb: 0.005%, Ti: 0.005%, Al: 0.015%, Cr: 0.015%, Cu: 0.10%, Si: 0.16%, P: 0.008%, S: 0.004%, the balance is Fe and other inevitable impurities; the chemical composition of the E47 steel plate is: C: 0.06%, Si: 0.60%, Mn: 1.55%, Cr: 0.2%, Ni: 0.15%, P: 0.015%, S: 0.005%; the welding method using the above-mentioned gas shielded welding wire includes the following steps: (1) The butt joint groove adopts a symmetrical V-shaped groove with a groove angle of 40°±2°, a groove gap of 8mm, and a pad on the back; (2) Remove the oil and rust stains on both sides of the weld between E47BCA steel plate and E47 steel plate; (3) The preheating temperature is 80°C, and the interlayer temperature is kept below 200°C; (4) Perform base welding: base welding current 160~170A, arc voltage 24~25V, welding speed 10~11cm / min; (5) Perform filling welding: the welding current of filling welding is 190~200A, the arc voltage is 24~25V, and the welding speed is 18~19cm / min; (6) Perform cover welding: The welding current of cover welding is 190~200A, the arc voltage is 24~25V, and the welding speed is 16~17cm / min.

2. The welding method according to claim 1, characterized in that: The protective gas is pure CO2.

3. The welding method according to claim 1, characterized in that: The welding current is direct current.

4. The welding method according to claim 1, characterized in that: The liner is a ceramic liner.

5. The welding method according to claim 1, characterized in that: In step (4), the base welding adopts a single-sided welding and double-sided forming welding technique.

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