阅读说明：本技术 一种抗拉强度为800MPa级工程机械钢双丝埋弧焊接方法 (Double-wire submerged arc welding method for engineering mechanical steel with tensile strength of 800MPa ) 是由 牟文广 黄治军 黄静 陈浮 郑绍鹏 于 2021-08-26 设计创作，主要内容包括：一种抗拉强度为800MPa级工程机械钢采用双丝埋弧焊接方法：采用抗拉强度为800MPa级别工程机械钢；坡口采用双面V型对称坡口；材料匹配：采用埋弧焊丝；前焊丝直径为Ф2.4mm,后焊丝直径为Ф3.2mm；焊接工艺规范；焊接。本发明通过焊接材料匹配及采用双细焊丝进行埋弧焊接等技术,使焊接接头具有良好的低温韧性及塑性；焊接线能量无明显增大,并使接头的综合力学性能得到保证；能减少弧光及噪音,从而极大改善操作人员的工作环境。(A double-wire submerged arc welding method for engineering mechanical steel with the tensile strength of 800MPa comprises the following steps: engineering mechanical steel with the tensile strength of 800MPa is adopted; the groove adopts a double-sided V-shaped symmetrical groove; material matching: adopting a submerged arc welding wire; the diameter of the front welding wire is phi 2.4mm, and the diameter of the rear welding wire is phi 3.2 mm; the welding process is standard; and (6) welding. According to the invention, through the technologies of matching welding materials and adopting double thin welding wires to carry out submerged arc welding and the like, a welding joint has good low-temperature toughness and plasticity; the welding line energy is not obviously increased, and the comprehensive mechanical property of the joint is ensured; can reduce arc light and noise, thereby greatly improving the working environment of operators.)

1. A double-wire submerged arc welding method for engineering mechanical steel with 800 MPa-level tensile strength comprises the following steps:

1) the tensile strength of the engineering mechanical steel is 800MPa, and the mechanical properties are as follows: tensile strength Rm is more than or equal to 800MPa, elongation A is more than or equal to 14 percent, and the tensile strength Rm is-20 oCKV₂The impact work is more than or equal to 46J; adopting equal-thickness combination to carry out double-wire submerged arc welding;

2) the welding groove adopts a double-sided V-shaped symmetrical groove, the angle of the groove is 50-60 degrees, and the truncated edge is 3-5 mm;

3) matching welding materials: adopting a submerged arc welding wire; the tensile strength of the welding wire deposited metal is more than 820 MPa; the diameter of the front welding wire is phi 2.4mm, and the diameter of the rear welding wire is phi 3.2 mm;

4) the welding process is standardized: welding current of a front welding wire: 410-455A, welding voltage: 29-31V; welding current of a rear welding wire: 458-483A, welding voltage: 31-33V; the welding speed of the front welding wire and the welding speed of the rear welding wire are both 45-60 cm/min, the energy of the welding wire is 22-35 kJ/cm, and CHF105 is adopted as a welding flux;

5) and (3) welding:

a. preheating to a temperature not exceeding 160 ℃ before welding;

b. multilayer and multi-channel continuous welding is adopted, and the interlayer temperature is controlled to be 160-200 ℃; carrying out reverse side welding under the condition of not needing back chipping;

c. and (4) after welding, carrying out dehydrogenation treatment at 300-350 ℃ for 4 h.

2. The method for submerged arc welding of the engineering mechanical steel with the tensile strength of 800MPa by using the double wires as the claim 1, is characterized in that: the welding current of the front welding wire is 418-449A; the welding current of the back welding wire is 458-478A.

3. The method for submerged arc welding of the engineering mechanical steel with the tensile strength of 800MPa by using the double wires as the claim 1, is characterized in that: the welding speed of the front welding wire and the welding speed of the rear welding wire are both 48-56 cm/min, and the energy of the welding wire is 22-32 kJ/cm.

4. The method for submerged arc welding of the engineering mechanical steel with the tensile strength of 800MPa by using the double wires as the claim 1, is characterized in that: the deposited metal mechanical property tensile strength R of the front welding wire and the back welding wire_m820MPa or more, elongation A of 20% or more, and-20 ℃ KV₂The impact work is more than or equal to 128J.

Technical Field

The invention relates to a submerged-arc welding process for engineering mechanical steel, and particularly belongs to a double-wire submerged-arc welding method for engineering mechanical steel with the tensile strength of 800 MPa.

Background

With the development of engineering machinery to high parameters, the structural steel has higher and higher strength grade and higher yield ratio. The steel has a great quenching tendency during small-line energy welding during welding, a heat affected zone is easy to generate a great amount of hard and brittle martensite, and a welded joint is seriously embrittled; when welding with high heat input, the softening phenomenon is easily generated, and the strength of the welded joint is greatly reduced. And in severe cases, the toughness and plasticity of the welding joint are greatly reduced.

After retrieval:

the Chinese patent publication No. CN101733527 discloses a double-arc double-wire submerged arc welding process for steel for a wind tower, which is a process of bottoming the inner side of the wind tower by adopting CO2 gas protection and capping by adopting a double-arc double-wire welding process. The patent technology is a welding method adopting a composite welding technology. In the double-wire submerged arc welding process, two welding wires with the diameter of 4.0mm are adopted, the welding energy is more than 40kJ/cm, and the welding wire cannot replace the welding of steel for high-strength engineering machinery. If the technology is adopted in the field of the invention, the welding joint can generate serious softening phenomenon, so that the strength of the welding joint is influenced, and the plasticity and the toughness of the welding joint are even seriously reduced.

The Chinese patent publication No. CN102744498 discloses a 500 MPa-grade extra-thick bridge steel welding method, which adopts a symmetrical narrow-gap U-shaped groove, a gas shielded welding bottoming process, a double-wire submerged arc welding filling and cover surface welding process, wherein the CO2 gas shielded welding heat input is 20-30kJ/cm, and the double-wire submerged arc welding heat input is 40-50 kJ/cm. The process is suitable for welding steel grades with lower strength. When the high-strength engineering mechanical steel is welded by adopting the technology, the structure of a heat affected zone is changed due to the excessive welding line energy, and further, the strength and the toughness are reduced.

A Q420qD steel double-wire submerged-arc welding process is introduced in a novel bridge steel Q420Q double-wire submerged-arc welding technology application disclosed in welding 2011, No. 5P 32-35, the welding process is characterized in that welding materials are H08MnMoA, the diameter of a welding wire is phi 5mm, and the process is mainly used for thick bridge steel plates. The double-wire submerged arc welding process with the diameter of phi 5mm is mainly suitable for welding steel grades insensitive to heat input, high-strength steel is sensitive to heat input, the comprehensive performance of a joint is seriously reduced due to large heat input, and the double-wire submerged arc welding process cannot replace the double-wire submerged arc welding process.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a method for performing submerged arc welding by matching welding materials and adopting double thin welding wires, so that a welding joint has good low-temperature toughness and plasticity; the welding line energy does not need to be increased, and the comprehensive mechanical property of the joint is ensured; can reduce arc light and noise, thereby greatly improving the tensile strength of the working environment of operators to 800MPa grade engineering mechanical steel and adopting a double-wire submerged arc welding method.

The measures for realizing the aim are as follows:

a double-wire submerged arc welding method for engineering mechanical steel with 800 MPa-level tensile strength comprises the following steps:

1) the tensile strength of the engineering mechanical steel is 800MPa, and the mechanical properties are as follows: tensile strength Rm is more than or equal to 800MPa, elongation A is more than or equal to 14 percent, and the tensile strength Rm is-20 oCKV₂The impact work is more than or equal to 46J; adopting equal-thickness combination to carry out double-wire submerged arc welding;

2) the welding groove adopts a double-sided V-shaped symmetrical groove, the angle of the groove is 50-60 degrees, and the truncated edge is 3-5 mm;

3) matching welding materials: adopting a submerged arc welding wire; the tensile strength of the welding wire deposited metal is more than 820 MPa; the diameter of the front welding wire is phi 2.4mm, and the diameter of the rear welding wire is phi 3.2 mm;

4) the welding process is standardized: welding current of a front welding wire: 410-455A, welding voltage: 29-31V; welding current of a rear welding wire: 458-483A, welding voltage: 31-33V; the welding speed of the front welding wire and the welding speed of the rear welding wire are both 45-60 cm/min, the energy of the welding wire is 22-35 kJ/cm, and CHF105 is adopted as a welding flux;

5) and (3) welding:

a. preheating to a temperature not exceeding 160 ℃ before welding;

b. multilayer and multi-channel continuous welding is adopted, and the interlayer temperature is controlled to be 160-200 ℃; carrying out reverse side welding under the condition of not needing back chipping;

c. and (4) after welding, carrying out dehydrogenation treatment at 300-350 ℃ for 4 h.

Preferably: the welding current of the front welding wire is 418-449A; the welding current of the back welding wire is 458-478A.

Preferably: the welding speed of the front welding wire and the welding speed of the rear welding wire are both 48-56 cm/min, and the energy of the welding wire is 22-32 kJ/cm.

It is characterized in that: the deposited metal mechanical property tensile strength R of the front welding wire and the back welding wire_m820MPa or more, elongation A of 20% or more, and-20 ℃ KV₂The impact work is more than or equal to 128J.

Action and mechanism of the main process in the invention

The groove adopts a double-sided V-shaped symmetrical groove, the angle of the groove is 50-60 degrees, the truncated edge is 3-5 mm, the welding workload can be increased due to the overlarge angle of the groove, and the adjustment of the comprehensive performance of a heat affected zone is not facilitated due to the undersize angle of the groove. The main purpose of adopting the blunt edge is that under the process, when the back side is welded, under the condition of not back chipping, the good fusion of the front side and the back side can be ensured through the heat input of the front wire parameters.

The tensile strength of the metal deposited by the welding wire is more than 820 MPa; the diameter of the front welding wire is phi 2.4mm, the diameter of the rear welding wire is phi 3.2mm, and the tensile strength of a welding joint is not lower than that of a base metal because the welding wire with the tensile strength of welding wire deposited metal larger than 820MPa is adopted; the front wires are 2.4mm in diameter and mainly play a role in ensuring the penetration, and the rear wires are mainly used for filling and renting.

According to the invention, the welding speed of the front welding wire and the welding speed of the rear welding wire are both 45-60 cm/min, the welding line energy is 22-35 kJ/cm, preferably the welding speed of the front welding wire and the welding speed of the rear welding wire are both 48-56 cm/min, the welding line energy is 22-32 kJ/cm, and the flux adopts CHF105, so that the proper welding speed can well control the line energy and the good forming of the welding line, thereby ensuring the comprehensive performance of the welding joint.

The invention carries out dehydrogenation treatment at 300-350 ℃ for +4h after welding, and the dehydrogenation treatment can accelerate the escape of hydrogen in a welding seam and a heat affected zone and prevent high-strength steel from generating welding cracks.

Compared with the prior art, the invention ensures that a welding joint has good low-temperature toughness and plasticity by the technologies of matching welding materials, adopting double thin welding wires for submerged arc welding and the like; the welding line energy is not obviously increased, and the comprehensive mechanical property of the joint is ensured; can reduce arc light and noise, thereby greatly improving the working environment of operators.

Drawings

FIG. 1 is a schematic diagram of a groove structure of the present invention;

in the figure: the angle of the groove is 50-60 degrees; the thickness of the blunt edge is 3-5 mm.

Detailed Description

The present invention is described in detail below:

example 1

A double-wire submerged arc welding method for engineering mechanical steel with 800 MPa-level tensile strength comprises the following steps:

1) the tensile strength of the engineering mechanical steel is 800MPa, the test plate size is 600mm multiplied by 400mm multiplied by 20mm, and the mechanical properties of the experimental plate are as follows: tensile strength Rm is more than or equal to 800MPa, elongation A is more than or equal to 14 percent, and KV is at minus 20 DEG C₂The impact work is more than or equal to 46J; the thickness of the steel plate is 20mm, and double-wire submerged arc welding is carried out by adopting equal-thickness combination;

2) the welding groove adopts a double-sided V-shaped symmetrical groove, the angle of the groove is 60 degrees, and the truncated edge is 3 mm;

3) matching welding materials: adopting a submerged arc welding wire; the tensile strength of the welding wire deposited metal is 823 MPa; the diameter of the front welding wire is phi 2.4mm, and the diameter of the rear welding wire is phi 3.2 mm.

4) The welding process is standardized: welding current of a front welding wire: 410A, welding voltage: 30V; welding current of a rear welding wire: 458A, welding voltage: 31V; the welding speed of the front welding wire and the welding speed of the rear welding wire are both 60cm/min, the energy of the welding wire is 26kJ/cm, and CHF105 is adopted as a welding flux;

5) and (3) welding:

a. preheating to the temperature of 110 ℃ before welding;

b. multilayer and multi-channel continuous welding is adopted, and the interlayer temperature is controlled at 163 ℃; carrying out reverse side welding under the condition of not needing back chipping;

c. after welding, dehydrogenation treatment is carried out according to 305 ℃ for +4 h.

Through detection, the mechanical properties of the butt joint of the embodiment are as follows: tensile strength R_m825MPa, cold bending d =3a of the joint, 180 degrees of qualified products, and-20 ℃ KV of three-zone impact energy welding line of the joint₂Is 118J, and the impact power of a fusion line is-20 KV₂127J, heat affected zone (1 mm) -20 KV₂= 130J。

Example 2

A double-wire submerged arc welding method for engineering mechanical steel with 800 MPa-level tensile strength comprises the following steps:

1) the tensile strength of the engineering mechanical steel is 800MPa, the test plate size is 600mm multiplied by 400mm multiplied by 20mm, and the mechanical properties of the experimental plate are as follows: tensile strength Rm is more than or equal to 800MPa, elongation A is more than or equal to 14 percent, and KV is at minus 20 DEG C₂The impact work is more than or equal to 46J; the thickness of the steel plate is 26mm, and double-wire submerged arc welding is carried out by adopting equal-thickness combination;

2) the welding groove adopts a double-sided V-shaped symmetrical groove, the angle of the groove is 55 degrees, and the truncated edge is 4 mm;

3) matching welding materials: adopting a submerged arc welding wire; the tensile strength of the welding wire deposited metal is 825 MPa; the diameter of the front welding wire is phi 2.4mm, and the diameter of the rear welding wire is phi 3.2 mm.

4) The welding process is standardized: welding current of a front welding wire: 425A, welding voltage: 29.5V; welding current of a rear welding wire: 465A, welding voltage: 31.5V; the welding speed of the front welding wire and the welding speed of the rear welding wire are both 55cm/min, the energy of the welding wire is-30 kJ/cm, and CHF105 is adopted as a welding flux;

5) and (3) welding:

a. preheating to 125 ℃ before welding;

b. multilayer and multi-channel continuous welding is adopted, and the interlayer temperature is controlled at 170 ℃; carrying out reverse side welding under the condition of not needing back chipping;

c. after welding, dehydrogenation treatment is carried out according to the temperature of 320 ℃ for 4 h.

Through detection, the mechanical properties of the butt joint of the embodiment are as follows: tensile strength R_m815MPa, cold bending d =3a of the joint, 180 degrees of qualified products, three-zone impact energy welding line of the joint, 20 ℃ below zero KV₂Is 108J, and the impact power of a fusion line is-20 KV₂125J, heat affected zone (1 mm) -20 KV₂= 127J。

Example 3

A double-wire submerged arc welding method for engineering mechanical steel with 800 MPa-level tensile strength comprises the following steps:

1) adopting engineering mechanical steel with the tensile strength of 800MPa grade and the test plate size of 600mm multiplied by 400mm multiplied by 20mm, the mechanical properties of the experimental plate are as follows: tensile strength Rm is more than or equal to 800MPa, elongation A is more than or equal to 14 percent, and KV is at minus 20 DEG C₂The impact work is more than or equal to 46J; the thickness of the steel plate is 35mm, and double-wire submerged arc welding is carried out by adopting equal-thickness combination;

2) the welding groove adopts a double-sided V-shaped symmetrical groove, the angle of the groove is 50 degrees, and the truncated edge is 4 mm;

3) matching welding materials: adopting a submerged arc welding wire; the tensile strength of the welding wire deposited metal is 825 MPa; the diameter of the front welding wire is phi 2.4mm, and the diameter of the rear welding wire is phi 3.2 mm.

4) The welding process is standardized: welding current of a front welding wire: 450A, welding voltage: 29V; welding current of a rear welding wire: 475A, welding voltage: 32V; the welding speed of the front welding wire and the welding speed of the rear welding wire are both 55cm/min, the energy of the welding wire is within 31kJ/cm, and CHF105 is adopted as a welding flux;

5) and (3) welding:

a. preheating to 145 ℃ before welding;

b. multilayer and multi-channel continuous welding is adopted, and the interlayer temperature is controlled at 185 ℃; carrying out reverse side welding under the condition of not needing back chipping;

c. after welding, dehydrogenation treatment is carried out at 340 ℃ for 4 h.

Through detection, the mechanical properties of the butt joint of the embodiment are as follows: tensile strength R_m820MPa, cold bending d =3a of the joint, 180 degrees of qualified products, three-zone impact energy welding line of the joint, 20 ℃ below zero KV₂107J, weld line impact power of-20 KV₂123J, heat affected zone (1 mm) -20 KV₂= 123J。

Example 4

A double-wire submerged arc welding method for engineering mechanical steel with 800 MPa-level tensile strength comprises the following steps:

1) the tensile strength of the engineering mechanical steel is 800MPa, the test plate size is 600mm multiplied by 400mm multiplied by 20mm, and the mechanical properties of the experimental plate are as follows: tensile strength Rm is more than or equal to 800MPa, elongation A is more than or equal to 14 percent, and KV is at minus 20 DEG C₂The impact work is more than or equal to 46J; the thickness of the steel plate is 40mm, and double-wire submerged arc welding is carried out by adopting equal-thickness combination;

2) the welding groove adopts a double-sided V-shaped symmetrical groove, the angle of the groove is 55 degrees, and the truncated edge is 5 mm;

3) matching welding materials: adopting a submerged arc welding wire; the tensile strength of the welding wire deposited metal is 825 MPa; the diameter of the front welding wire is phi 2.4mm, and the diameter of the rear welding wire is phi 3.2 mm.

4) The welding process is standardized: welding current of a front welding wire: 450A, welding voltage: 30V; welding current of a rear welding wire: 480A, welding voltage: 31.5V; the welding speed of the front welding wire and the welding speed of the rear welding wire are both 60cm/min, the energy of the welding wire is-28 kJ/cm, and CHF105 is adopted as a welding flux;

5) and (3) welding:

a. preheating to 155 ℃ before welding;

b. multilayer and multi-channel continuous welding is adopted, and the interlayer temperature is controlled at 180 ℃; carrying out reverse side welding under the condition of not needing back chipping;

c. after welding, dehydrogenation treatment is carried out at 345 ℃ for 4 h.

Through detection, the mechanical properties of the butt joint of the embodiment are as follows: tensile strength R_m820MPa, cold bending d =3a of the joint, 180 degrees of qualified products, three-zone impact energy welding line of the joint, 20 ℃ below zero KV₂103J, fusion line impact power-20 KV₂120J, heat affected zone (1 mm) -20 KV₂= 113J。

Example 5

A double-wire submerged arc welding method for engineering mechanical steel with 800 MPa-level tensile strength comprises the following steps:

1) the tensile strength of the engineering mechanical steel is 800MPa, the test plate size is 600mm multiplied by 400mm multiplied by 20mm, and the mechanical properties of the experimental plate are as follows: tensile strength Rm is more than or equal to 800MPa, elongation A is more than or equal to 14 percent, and KV is at minus 20 DEG C₂The impact work is more than or equal to 46J; the thickness of the steel plate is 40mm, and double-wire submerged arc welding is carried out by adopting equal-thickness combination;

2) the welding groove adopts a double-sided V-shaped symmetrical groove, the angle of the groove is 55 degrees, and the truncated edge is 5 mm;

3) matching welding materials: adopting a submerged arc welding wire; the tensile strength of the welding wire deposited metal is 822 MPa; the diameter of the front welding wire is phi 2.4mm, and the diameter of the rear welding wire is phi 3.2 mm.

4) The welding process is standardized: welding current of a front welding wire: 455A, welding voltage: 31V; welding current of a rear welding wire: 480A, welding voltage: 31.5V; the welding speed of the front welding wire and the welding speed of the rear welding wire are both 52cm/min, the energy of the welding wire is within 33kJ/cm, and CHF105 is adopted as a welding flux;

5) and (3) welding:

a. preheating to 160 ℃ before welding;

b. multilayer and multi-channel continuous welding is adopted, and the interlayer temperature is controlled at 190 ℃; carrying out reverse side welding under the condition of not needing back chipping;

c. after welding, dehydrogenation treatment is carried out according to 350 ℃ for 4 h.

Through detection, the mechanical properties of the butt joint of the embodiment are as follows: tensile strength R_m820MPa, cold bending d =3a of the joint, 180 degrees of qualified products, three-zone impact energy welding line of the joint, 20 ℃ below zero KV₂Is 101J, and the impact power of a fusion line is-20 KV₂115J, heat affected zone (1 mm) -20 KV₂= 113J。

The present embodiments are merely preferred examples, and are not intended to limit the scope of the present invention.