阅读说明：本技术 基于细丝气体保护焊接的低碳微合金钢焊接性评估方法 (Low-carbon microalloyed steel weldability assessment method based on filament gas shielded welding ) 是由 刘硕 于 2020-05-27 设计创作，主要内容包括：本发明涉及一种基于细丝气体保护焊接的低碳微合金钢焊接性评估方法,其步骤依次包括：选用试验板为低碳微合金钢板；选用直径为1.2mm的气体保护实芯焊丝；所述一对试验板进行平焊位置对接焊,其坡口形式为正面的一侧为带直边侧和钝边的第一V形坡口,正面的另一侧为带钝边的第二V形坡口,当钢板厚度t＞20mm时,第二V形坡口为双V形坡口；采用脉冲短路过渡模式进行单面焊双面成型根焊；采用熔化极气体保护焊接进行填充盖面焊接,热输入为1.0～2.0kJ/mm；观察和检测焊接接头裂纹倾向以评估材料工艺焊接性,并通过焊接接头力学性能检测以评估材料使用焊接性。本发明兼顾工艺焊接性和使用焊接性评估需求,对不同领域使用的低碳微合金钢焊接性评估具有普适性。(The invention relates to a low-carbon microalloyed steel weldability assessment method based on filament gas shielded welding, which sequentially comprises the following steps: selecting a test plate as a low-carbon microalloy steel plate; selecting a gas shielded solid welding wire with the diameter of 1.2 mm; the pair of test plates are subjected to butt welding at the flat welding positions, the groove form is that one side of the front surface of each test plate is a first V-shaped groove with a straight side and a truncated side, the other side of the front surface of each test plate is a second V-shaped groove with a truncated side, and when the thickness t of the steel plate is more than 20mm, the second V-shaped groove is a double V-shaped groove; adopting a pulse short circuit transition mode to carry out single-side welding and double-side forming root welding; performing filling cover surface welding by adopting gas metal arc welding, wherein the heat input is 1.0-2.0 kJ/mm; the crack tendency of the welding joint is observed and detected to evaluate the process weldability of the material, and the mechanical property detection of the welding joint is used to evaluate the service weldability of the material. The method gives consideration to both the requirements of process weldability and use weldability evaluation, and has universality for evaluation of the weldability of the low-carbon micro-alloy steel used in different fields.)

1. A low-carbon microalloy steel weldability assessment method based on filament gas shielded welding is characterized in that: the method comprises the following steps:

selecting a test plate as a low-carbon microalloy steel plate;

selecting a gas shielded solid welding wire with the diameter of 1.2 mm;

step three, butt welding the flat welding positions of the pair of test plates, wherein the groove form is as follows: one side of the front surface is provided with a first V-shaped groove with a straight edge and a blunt edge, the bevel surface of the first V-shaped groove forms an angle alpha with the central axis of the groove, the other side of the front surface is provided with a second V-shaped groove with a blunt edge, and the bevel surface of the second V-shaped groove forms an angle beta with the central axis of the groove₁Wherein α is 30 to 60 °, β₁35 ~ 55, test board truncated edge clearance an is 2 ~ 5mm, and test board truncated edge height b is 0.2 ~ 2.5mm, first V-arrangement groove height c₁2-5 mm; when the thickness t of the steel plate is more than 20mm, the bevel face of the second V-shaped groove forms an angle beta with the central axis of the groove₂The bevel face of the second V-shaped groove deflects outwards and forms an angle gamma with the central axis of the groove to form a double V-shaped groove, wherein the angle beta₂30-50 degrees, gamma 5-25 degrees, and a first V-shaped groove height c₂Is 2 ~ 7mm, and the downside V-arrangement groove height d and the steel sheet thickness t of two V-arrangement grooves satisfy the relational expression: t is 1/4 and d is 2/5;

step four, adopting a pulse short circuit transition mode to carry out single-side welding and double-side forming root welding on the test board, wherein: the welding protective gas is a mixed gas of argon and carbon dioxide, and the welding technological parameters are as follows: the welding current is 110-160A, the welding voltage is 13-18V, and the welding speed is 170-240 mm/min; in the welding process, an included angle delta formed by a welding gun and the straight side of the first V-shaped groove is 10-40 degrees along the width direction of the groove;

and step five, performing filling cover surface welding on the test plate in a consumable electrode gas shielded welding mode, wherein: the welding protective gas is mixed gas of argon and carbon dioxide, the welding heat input E is 1.0-2.0 kJ/mm, and the welding technological parameters are as follows: the welding current is 210-270A, the welding voltage is 19-28V, the welding speed is 200-300 mm/min, and the combination of the welding current, the welding voltage and the welding speed can be matched with the welding heat input value required by the test on the premise of ensuring the welding seam forming quality; the swing width of the welding gun is within 1-3 mm from the edge of the groove; in the welding process, an included angle delta formed by a welding gun and the straight side of the first V-shaped groove is 10-40 degrees along the width direction of the groove;

and step six, obtaining a welding joint after welding, observing and detecting the crack tendency of the welding joint to evaluate the technological weldability of the material, and evaluating the service weldability of the material through the mechanical property detection of the welding joint.

2. The method for evaluating the weldability of low carbon microalloyed steel based on filament gas shielded welding as claimed in claim 1, characterized in that: and in the sixth step, the mechanical property detection comprises the detection of the low-temperature impact and the fracture toughness of the coarse crystal area of the welding heat affected zone adjacent to the single-side straight-edge fusion line.

3. The method for evaluating weldability of low carbon micro alloy steel based on filament gas shielded welding according to claim 1 or 2, characterized in that: and fifthly, the swinging path of the welding gun is zigzag, the staying time of the welding gun at the straight side of the first V-shaped groove is 100-300 ms, and the staying time of the welding gun at the oblique side of the second V-shaped groove is 50-150 ms.

4. Filament gas based according to claim 1 or 2The method for evaluating the weldability of the low-carbon microalloyed steel for body-protecting welding is characterized by comprising the following steps of: the mixing ratio of the welding protective gas in the fourth step and the welding protective gas in the fifth step is Ar to CO₂The gas flow rate is 18-25L/min, wherein the gas flow rate is 80: 20.

Technical Field

The invention relates to a microalloyed steel welding technology, in particular to a low-carbon microalloyed steel weldability assessment method based on solid filament gas shielded welding.

Background

For an important engineering structure using low-carbon microalloy steel, welding is a key process of field installation and construction, the welding quality and efficiency also determine the quality and efficiency of an engineering project, and the quality of the field weldability of the low-carbon microalloy steel material directly influences the quality and safety service of a welded joint. Generally, the weldability of a material includes process weldability, which mainly refers to the ability to avoid welding defect problems (including various types of welding crack sensitivity) and obtain a continuous and complete welding joint during welding, and use weldability, which mainly refers to the use properties (including mechanical properties such as strength, plasticity, toughness and the like) of the welding joint.

Recently, foreign high-grade pipeline users put forward the evaluation requirements of pipeline steel pipe field weldability under a certain welding heat input condition, including process weldability and use weldability, particularly, the test position of the low-temperature impact and fracture toughness of a welded joint needs to be accurately positioned in a theoretically weakest welding heat affected zone coarse crystal zone (CGHAZ), so that the embrittlement tendency of the material under a certain welding heat input condition is systematically evaluated. Here, for low-carbon microalloy pipeline steel with a certain specification, welding heat input has important influence on solid-state phase change and microstructure evolution of a welding joint, and further influences integral embrittlement and service safety of the joint. Therefore, low carbon microalloyed pipeline steel tends to exhibit different weldability under different welding heat input conditions.

At present, many methods for evaluating weldability, i.e. weld crack sensitivity, of a steel material process are available, such as: the ISO 17642-2 standard provides a TEKKEN test for evaluating the cold crack sensitivity of a plate, which is similar to the oblique Y-shaped groove welding crack test method described in GB 4675.1, welding of a small-scale test welding line is carried out under a high constraint condition, so that the cold crack sensitivity of a material under a certain welding condition is evaluated, however, the constraint condition of the evaluation method is too harsh, and the test welding line is a single welding line in an irregular shape, so that high welding residual stress exists, and cold cracks are more favorably induced. GB/T13817 provides a rigidity restraint welding crack test method, which completely fixes a test steel plate on a bottom plate with a very large thickness, residual stress cannot be released in the welding process, cold cracks are easily induced in a joint area, the method is also conservative, and the welding joint form is also greatly different from the common joint form of a low-carbon microalloy steel structure, and has no direct field construction welding guidance function. An improved oblique Y-shaped groove welding crack sensitivity test specimen disclosed in Chinese patent 201611208203.5 and a manufacturing method thereof, and a constrained weld manufacturing method for an oblique Y-shaped groove welding crack test disclosed in Chinese patent 201510012348.7 can only solve the problem of indirect evaluation of weldability under certain conditions. The above-mentioned patent and non-patent documents both focus on indirect evaluation of process weldability, and have a certain referential significance for on-site welding construction of low-carbon microalloy steel structures, but have no direct guidance, and mainly the use weldability cannot be considered, and the design form of joints and implementation details of welding process methods are greatly different from the construction welding conditions of the mainstream low-carbon microalloy steel structures.

Chinese patent 201410516996.1 discloses a method for welding steel plates for ocean platforms, which adopts a general K-shaped groove form, if the implementation process of the welding process is properly controlled, a fusion line with certain straightness on one side can be obtained after welding, and the requirements of CGHAZ position impact and fracture toughness sampling are met, but the method aims at the specific product structure of a super-thick plate (such as 50-150 mm), has no universality in various industrial fields, and does not relate to the straightness guarantee measure of the fusion line with straight edges on one side, the straightness of the fusion line after welding is easily guaranteed when the steel plate is thick, and the straightness of the fusion line is easily damaged by a welding pool when the steel plate is thin. Chinese patent 201510385434.2 discloses a CTOD test method for a large thick plate welding repair joint, and chinese patent 201510605044.1 discloses a welding repair CTOD test method, both of which have certain characteristics of a single-side straight-edge weld line even when the plate thickness is thick, but both of which belong to repair processing measures after defects are found in a finished product welded part, and cannot meet the requirements of low-carbon microalloyed steel with universality in a certain welding heat input range for simultaneously evaluating technological weldability and using weldability.

Disclosure of Invention

The invention aims to provide a method for evaluating the weldability of low-carbon microalloy steel based on filament gas shielded welding, which is characterized in that under the condition of a certain range of heat input, a welding joint with a good straightness of a single-side fusion line is obtained by optimally designing the groove form of a single-side straight edge, constructing a welding process parameter combination, controlling the inclination angle of a welding gun and the quality of a welding process, and the welding joint is observed and detected to evaluate the process weldability and the use weldability of materials.

The invention is realized by the following steps:

a low-carbon microalloy steel weldability assessment method based on filament gas shielded welding comprises the following steps:

selecting a test plate as a low-carbon microalloy steel plate;

selecting a gas shielded solid welding wire with the diameter of 1.2 mm;

step three, butt welding the flat welding positions of the pair of test plates, wherein the groove form is as follows: one side of the front surface is provided with a first V-shaped groove with a straight edge and a blunt edge, the bevel surface of the first V-shaped groove forms an angle alpha with the central axis of the groove, the other side of the front surface is provided with a second V-shaped groove with a blunt edge, and the bevel surface of the second V-shaped groove forms an angle beta with the central axis of the groove₁Wherein α is 30 to 60 °, β₁35 ~ 55, test board truncated edge clearance an is 2 ~ 5mm, and test board truncated edge height b is 0.2 ~ 2.5mm, first V-arrangement groove height c₁2-5 mm; when the thickness t of the steel plate is more than 20mm, the bevel face of the second V-shaped groove forms an angle beta with the central axis of the groove₂The bevel face of the second V-shaped groove deflects outwards and forms an angle gamma with the central axis of the groove to form a double V-shaped groove, wherein the angle beta₂30-50 degrees, gamma 5-25 degrees, and a first V-shaped groove height c₂Is 2 ~ 7mm, and the downside V-arrangement groove height d and the steel sheet thickness t of two V-arrangement grooves satisfy the relational expression: t is 1/4 and d is 2/5;

step four, adopting a pulse short circuit transition mode to carry out single-side welding and double-side forming root welding on the test board, wherein: the welding protective gas is a mixed gas of argon and carbon dioxide, and the welding technological parameters are as follows: the welding current is 110-160A, the welding voltage is 13-18V, and the welding speed is 170-240 mm/min; in the welding process, an included angle delta formed by a welding gun and the straight side of the first V-shaped groove is 10-40 degrees along the width direction of the groove;

and step five, performing filling cover surface welding on the test plate in a consumable electrode gas shielded welding mode, wherein: the welding protective gas is mixed gas of argon and carbon dioxide, the welding heat input E is 1.0-2.0 kJ/mm, and the welding technological parameters are as follows: the welding current is 210-270A, the welding voltage is 19-28V, the welding speed is 200-300 mm/min, and the combination of the welding current, the welding voltage and the welding speed can be matched with the welding heat input value required by the test on the premise of ensuring the welding seam forming quality; the swing width of the welding gun is within 1-3 mm from the edge of the groove; in the welding process, an included angle delta formed by a welding gun and the straight side of the first V-shaped groove is 10-40 degrees along the width direction of the groove;

and step six, obtaining a welding joint after welding, observing and detecting the crack tendency of the welding joint to evaluate the technological weldability of the material, and evaluating the service weldability of the material through the mechanical property detection of the welding joint.

And in the sixth step, the mechanical property detection comprises the detection of the low-temperature impact and the fracture toughness of the coarse crystal area of the welding heat affected zone adjacent to the single-side straight-edge fusion line.

And fifthly, the swinging path of the welding gun is zigzag, the staying time of the welding gun at the straight side of the first V-shaped groove is 100-300 ms, and the staying time of the welding gun at the oblique side of the second V-shaped groove is 50-150 ms.

The mixing ratio of the welding protective gas in the fourth step and the welding protective gas in the fifth step is Ar to CO₂The gas flow rate is 18-25L/min, wherein the gas flow rate is 80: 20.

According to the low-carbon microalloy steel weldability evaluation method based on filament gas shielded welding, firstly, under the condition that the heat input is 1.0-2.0 kJ/mm, the welding method of the thin-diameter gas shielded solid welding wire has good representativeness in various industrial fields, and can provide direct guidance significance and important reference value. Secondly, by optimally designing a special welding joint groove form of the single-side straight edge, constructing and matching a scientific and reasonable welding process parameter combination (comprising welding current, welding voltage, welding speed and welding gun swinging mode), welding gun inclination angle and welding process quality control, a welding joint with a single-side fusion line with good straightness can be obtained, and proper welding gun swinging is combined, so that the welding joint forming quality of uniform spreading of a welding seam can be improved, heat after the welding joint enters a high-heat input range (1.5-2.0 kJ/mm) can be dispersed, welding defects are avoided, the proper groove width can meet the welding gun swinging requirement, and the straight edge fusion side quality is ensured.

The present invention can evaluate the technological weldability of the material by observing and detecting the crack tendency of the welded joint. Through the detection of mechanical properties of a welding joint, particularly the detection of low-temperature impact and fracture toughness of a coarse grain zone (CGHAZ) of a welding heat affected zone adjacent to a single-side straight-edge fusion line, and the straightness of the single-side straight-edge fusion line can ensure that 80% of impact toughness sampling notch grooves are positioned in the CGHAZ, the use weldability of the material under a certain heat input condition can be evaluated, namely the evaluation requirements of process weldability and use weldability are considered at the same time, and the method has universal applicability to the evaluation of the weldability of low-carbon microalloy steel used in different industries and fields in a given welding heat input range. Meanwhile, the characteristic of the single-side straight-edge fusion line ensures that the CGHAZ which is the weakest theoretically is positioned at the test position accurately in the impact toughness and fracture toughness sampling process, and compared with the actual welding condition of field installation construction, the invention has high safety margin and has important reference value for field safety construction and operation.

Compared with the prior art, the invention has the following beneficial effects: the method has universality, can simultaneously meet the evaluation requirements of the process weldability and the use weldability under the given heat input condition, and has the advantages of convenient implementation, flexible operation, low requirement on hardware equipment, low implementation cost and good reproducibility.

Drawings

FIG. 1 is a schematic structural diagram of a welding joint groove form with a steel plate thickness not more than 20mm according to the low-carbon micro-alloy steel weldability evaluation method based on filament gas shielded welding;

FIG. 2 is a schematic structural view of the present invention in the form of a weld joint groove having a steel plate thickness of more than 20 mm;

FIG. 3 is a schematic view of the inclination angle of the welding gun of the present invention in the direction along the width of the bevel;

FIG. 4 is a schematic diagram of a specific weld joint groove form employed by an embodiment of the present invention.

In the figure, 1 test panel, 2 welding torch.

Detailed Description

The invention is further described with reference to the following figures and specific examples.

Referring to fig. 1 to 3, a method for evaluating weldability of low-carbon microalloyed steel based on filament gas shielded welding mainly aims at the situation of 1.0 to 2.0kJ/mm welding heat input range commonly used for gas shielded welding of a consumable electrode, applies a gas shielded solid wire with the diameter of 1.2mm, combines the characteristics of a welding arc and a molten pool under a given heat input condition, constructs and matches a welding process parameter combination (including welding current, welding voltage, welding speed and welding gun swing mode), a welding gun inclination angle and welding process quality control, particularly a weld line straightness control technology and the like by optimally designing a groove form of a single-side straight-edge welding joint suitable for the welding condition, and obtains a welding joint with good quality defects, and comprises the following steps:

step one, selecting a test plate 1 as a low-carbon microalloy steel plate.

And step two, selecting a gas shielded solid welding wire with the diameter of 1.2 mm.

Step three, performing butt welding on the flat welding positions of the pair of test plates 1:

referring to fig. 1, when the thickness t of the steel plate is less than or equal to 20mm, the groove form is as follows: one side of the front surface is provided with a first V-shaped groove with a straight edge and a blunt edge, the bevel surface of the first V-shaped groove forms an angle alpha with the central axis of the groove, the other side of the front surface is provided with a second V-shaped groove with a blunt edge, and the bevel surface of the second V-shaped groove forms an angle beta with the central axis of the groove₁Wherein α is 30 to 60 °, β₁35 ~ 55, test board truncated edge clearance an is 2 ~ 5mm, and test board truncated edge height b is 0.2 ~ 2.5mm, first V-arrangement groove height c₁2-5 mm.

Referring to fig. 2, when the thickness t of the steel plate is more than 20mm, the groove form is as follows: one side of the front surface is a first V-shaped groove with a straight edge and a blunt edge, the bevel surface of the first V-shaped groove forms an angle alpha with the central axis of the groove, and the other side of the front surface is a second V-shaped groove with a blunt edgeThe second V-shaped groove is a double V-shaped groove, and the lower side bevel face of the double V-shaped groove forms an angle beta with the central axis of the groove₂The lower side bevel face of the double V-shaped groove is outwards deflected to be an upper side bevel face, and the upper side bevel face forms an angle gamma with the central axis of the groove, wherein alpha is 30-60 degrees, and beta is beta₂30 ~ 50 ═ gamma is 5 ~ 25 ═ gamma, and test board truncated edge clearance a is 2 ~ 5mm, and test board truncated edge height b is 0.2 ~ 2.5mm, first V-arrangement groove height c₂Is 2 ~ 7mm, and the downside V-arrangement groove height d and the steel sheet thickness t of second V-arrangement groove satisfy the relational expression: t is 1/4 and d is 2/5.

By adopting the optimally designed welding joint groove form, the single-side straight edge design requirement is ensured, meanwhile, the fusion penetration quality of a single-side welding double-side forming root welding seam is favorably ensured, the defect that the straight edge side is not fused during special pulse short circuit transition root welding is avoided, the back welding seam is easily controlled to be uniformly spread and formed, the proper welding joint groove width can meet the welding gun swing requirement under the given heat input condition, and the fusion quality of the straight edge side is ensured.

Fourthly, carrying out single-side welding and double-side forming root welding on the test board by adopting a pulse short circuit transition mode (such as STT, RMD, PST and the like), wherein the welding protective gas is a mixed gas of argon and carbon dioxide, and the mixing ratio is Ar: CO₂The gas flow rate is 18-25L/min, wherein the gas flow rate is 80: 20. The welding process parameters are as follows: the welding current is 110-160A, the welding voltage is 13-18V, and the welding speed is 170-240 mm/min. Considering the particularity of the root welding of the single-side welding and double-side forming, the numerical range requirement of heat input does not exist.

And step five, performing filling capping welding (note: the original book of filing is filling welding, please confirm whether the filling capping welding needs to be changed or not) on the test plate 1 in a consumable electrode gas shielded welding mode, wherein the welding shielding gas is a mixed gas of argon and carbon dioxide, and the mixing ratio is Ar: CO₂The gas flow rate is 18-25L/min, wherein the gas flow rate is 80: 20. According to the welding heat input E of 1.0-2.0 kJ/mm, the welding technological parameters comprise welding current, welding voltage, welding speed, welding gun swing mode and the like, wherein: the welding current is 210-270A, the welding voltage is 19-28V, the welding speed is 200-300 mm/minOn the premise of ensuring the forming quality of the welding seam, the combination of the welding current, the welding voltage and the welding speed can be matched with the welding heat input condition required by the test. The welding gun is adopted to swing to improve the spreading and forming quality of the welding seam, and meanwhile, the heat after the welding gun enters a higher heat input interval (1.5-2.0 kJ/mm) can be dispersed, so that the defects of welding beading, local insufficient welding and the like caused by the fact that a welding pool is not solidified in time are avoided. The swing path of the welding gun is in a zigzag shape, the swing width of the welding gun is within a range of 1-3 mm from the edge of the groove, the dwell time of the welding gun 2 on the straight side of the first V-shaped groove is 100-300 ms, and the dwell time of the welding gun 2 on the oblique side of the second V-shaped groove is 50-150 ms, as shown in figure 3. The optimized welding gun swinging mode can ensure the sufficient fusion of the edge of the groove of the welding joint and prevent the molten pool from destroying the straightness of the straight side after welding. In a lower heat input range (1.0-1.5 kJ/mm), if good fusion of the edge of the groove can be ensured, the welding gun can adopt swing-free straight-pull welding.

Referring to fig. 3, in view of the sensitivity of the straight-side lack of fusion defects in the form of single-side straight-side bevels, in step four and step five, the welding gun is tilted in such a manner that: in the width direction of the groove, the welding gun 2 forms an included angle δ of 10-40 ° with the straight side of the first V-shaped groove. If the inclination angle is too small, the probability of occurrence of non-fusion defects on the straight side increases, and if the inclination angle is too large, the weld gun position-induced molten pool shape will destroy the straightness of the weld line after welding and is not favorable for welding gun swing. Meanwhile, in order to ensure that the straightness of the fusion line on the single side of the welding joint is good, the position of the welding gun in the welding bead needs to be monitored in real time in the welding process, if the welding gun deviates from the original setting position due to the problems of groove machining and group pairing precision, the position of the welding gun needs to be adjusted rapidly and timely, otherwise, the probability of the occurrence of the non-fusion defect on the straight side is increased.

And step six, obtaining a welding joint after welding, observing and detecting the crack tendency of the welding joint to evaluate the technological weldability of the material, and evaluating the use weldability of the material by detecting the mechanical properties of the welding joint, particularly detecting the low-temperature impact and the fracture toughness of a coarse crystal area of a welding heat affected area adjacent to a single-side straight-edge fusion line.

Examples

The test plate 1 is made of typical X70 pipeline steel with the thickness t being 22mm, and the welding heat input is in the range of 1.0-2.0 kJ/mm and the diameter is 1.2mm based on a gas shielded solid welding wire with the welding shielding gas of 80% Ar and 20% CO₂And (4) carrying out weldability evaluation test on the mixed gas with the flow of the shielding gas of 18-25L/min. Referring to fig. 4, the specific weld joint groove form is: positive one side is the first V-arrangement groove of taking straight avris and blunt edge, and positive opposite side is the second V-arrangement groove of taking the blunt edge, and second V-arrangement groove is two V-arrangement grooves, wherein: alpha is 45 deg. and beta₂＝30°，γ＝10°，a＝2～4mm，b＝1.6mm±0.8mm，c₂＝2～3mm，d＝8mm。

Table 1 lists the specific welding process parameters, torch tilt angle and corresponding weld heat input values for the fill-cap welding step of examples 1-6, as follows:

table 2 lists the results of the defect inspection and evaluation of the straight-side CGHAZ impact toughness for examples 1-6, as follows:

as can be seen from tables 1 and 2, the X70 pipeline steel process shown in different examples has good weldability, no welding cracks or other welding defects, the impact toughness at the CGHAZ position of the straight side at minus 10 ℃ is higher than the general acceptance standard requirement, namely the minimum impact work requirement is 34J (refer to NB/T47016: mechanical property test of welding test pieces of pressure-bearing equipment products), and the impact toughness is in a certain descending trend along with the increase of welding heat input.

The low-carbon microalloy steel weldability assessment method based on filament gas shielded welding has the advantages that the process weldability of materials in the welding process and the use weldability of materials after welding are considered, the gas shielded solid welding wire can ensure the stability and the forming quality of the welding process within a given welding heat input range, the operability and the reproducibility are good, and the method has universality and universality for weldability assessment of low-carbon microalloy steel materials used in different industries and fields.

The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.