KR20090083869A - Solid wire for carbonic acid gas welding - Google Patents

Abstract

A carbon dioxide gas welding solid wire is provided to obtain welding metal whereof mechanical performance like intensity and toughness etc. is excellent. A carbon dioxide gas welding solid wire contains C: 0.10 mass % through 0.03, Si: 1.00 mass % through 0.67, Mn: 2.50 mass % through 1.81, S: 0.018 mass % through 0.006, Ti: 0.150 mass % through 0.100, B: 0.0070 mass % through 0.0015, and Cu containing plating powder: 0.45 mass % through 0.10. The remnant is Fe and the inevitable impurity. The parameter PBS and PMT indicated as formulas satisfying PBS<=10, and PMT<=32.

Description

Solid wire for carbon dioxide gas welding {SOLID WIRE FOR CARBONIC ACID GAS WELDING}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a solid wire for carbon dioxide welding, wherein mild steel or high strength steel of 490 to 520 N / mm2 class is used for carbon dioxide shield arc welding. It relates to a solid wire for carbonic acid shield arc welding that can be obtained.

In recent years, the field of construction steel, the gas-shielded arc welding method that the CO ₂ in the shielding gas is mainly used because of its high efficiency Castle advantage. In the past, this gas shielded arc welding method was almost a human semi-automatic welding method. However, in order to further reduce the cost due to the increase in labor and the welding efficiency by the unmanned operation at night or on holiday, the automatic welding by the robot is also prevalent. On the other hand, in terms of welding quality, in order to improve the performance of welded joints, focusing on the improvement of vibration resistance, the upper limit on the temperature between heat input and pass during welding was revised by JASS6 amendment in 1997 and revision of Building Standard Act 1999. Management is prescribed. Due to this trend, welding wires are also allowed to heat up to 40 kJ / cm for 490N / mm2 grade carbon steel, up to 350 ° C between passes, and up to 30kJ / cm for up to 250 ° C for 520N / mm2 grade carbon steel sheets and to 250 ° C between passes. As it can be done, a wire corresponding to temperature between high heat input and high pass was developed, and in 1999, it was JIS standardized as 540 N / mm 2 class = YGW18. Since then, the 540N / mm <2> grade wire | wire which obtains the mechanical performance which is superior in the heat input and high pass temperature compared with the conventional wire is rapidly spread | diffused so far. Moreover, although this 540N / mm <2> wire spread | spreaded early in semi-automatic welding which is difficult to manage heat input and interpass temperature, in recent years, 540N / mm <2> wire is increasingly applied also to fully automatic welding by robot welding.

In the conventional high current / high pass temperature-corresponding wire for carbon dioxide gas welding, in general, it contains more deoxidation components such as Si, Mn, Ti, and Mo, B, Cr, Al, Nb, V, Ni etc. is added as needed. Thereby, the hardenability of steel is raised and the strength is raised by combining the improvement of toughness by refinement | miniaturization of a crystal grain, and the action of precipitation hardening and solid solution hardening.

However, these conventional wires are not all designed in consideration of use for welding by a robot. In the conventional high current / high pass temperature-corresponding wire, there is a drawback that the amount of slag generation is excessive and the peelability is bad. Because slag is insulative, deposited slag impairs arc stability and is a direct cause of defects such as insufficient penetration and slag incorporation. In addition, if the slag does not spontaneously detach to some extent, even if the welding robot tries to re-arc while slowing the start position, the arc start error continues to occur, and the welding robot stops by determining an error. Although the welding robot exhibits its greatest advantage by unmanned welding, it is necessary to deposit slag in a short time and cause instability of the arc in order to require high frequency of human slag removal work or to recover from an arc start error. The advantage cannot be exhibited, such as the slag removal of an arc start part. Therefore, in order to solve this problem, it has sufficient mechanical performance required for 490N / mm2 grade steel under conditions of maximum heat input of 40 kJ / cm and maximum interpass temperature of 350 deg. C, less slag generation, good peelability, and continuous stacking height. A large high efficiency welding wire was desired.

In response to such a demand, wires disclosed in Japanese Patent Laid-Open No. 2006-88187, Japanese Patent Laid-Open No. 2006-305605, and Japanese Patent Laid-Open No. 2006-150437 have been developed as wires having improved slag peelability. Further, wires having improved slag peelability and reduced slag generation amount are disclosed in Japanese Patent Laid-Open No. 2004-122170 and Japanese Patent Laid-Open No. 2006-26643.

However, the recent evolution of robot welding technology is remarkable. For this reason, the narrow improvement of 30 degree of improvement angle is implement | achieved. That is, while the angle of improvement is 35 ° as a standard, the number of passes is reduced and the welding time is shortened due to the reduction of the improvement area, the amount of weld wire used is reduced, the thermal strain is reduced, the strength and toughness due to the decrease in the temperature rise between the passes, and the like. For the purpose of improving the mechanical performance of the weld metal, the narrow improvement of about 30 ° can be realized. As described above, when the improvement angle becomes smaller, the torch nozzle is more likely to interfere with the improvement surface, and therefore, the distance from the tip of the chip to the improvement bottom and the so-called wire protrusion length are often increased, resulting in poor welding due to a decrease in arc force. It has been found that this is likely to occur. In addition, there is a tendency that the protruding length is deteriorated, the gas shielding property is deteriorated, nitrogen is mixed in the weld metal from the atmosphere, and the toughness is lowered.

Conventionally, there has not been disclosed a technique for preventing the penetration failure from the welding wire surface. In addition, there are no welding wires excellent in mechanical performance such as strength and toughness while realizing the conventional excellent slag peeling and minimizing slag amount. Therefore, development of the optimum welding wire which prevents a penetration failure, is excellent in mechanical performance, and can cope with narrow improvement construction in multilayer welding by a robot is desired.

This invention is made | formed in view of such a problem, and an object of this invention is to provide the solid wire for carbonic acid gas welding by which sufficient penetration is obtained even in narrow improvement construction and the welding metal which is excellent in mechanical performance, such as strength and toughness, is obtained.

The solid wire for carbonic acid gas welding which concerns on this invention is C: 0.03-0.10 mass%, Si: 0.67-1.00 mass%, Mn: 1.81-2.50 mass%, S: 0.006--0.018 mass%, Ti: 0.100- 0.150 mass%, B: 0.0015-0.0070 mass%, Cu: 0.10-0.45 mass% or less including plating powder, remainder is Fe and an unavoidable impurity, and the parameter P represented by following formula (1) and (2) _BS and P _MT satisfy P _BS ≤ 10 and P _MT ≤ 32, and are regulated to be P: 0.02% by mass or less, Nb: 0.04% by mass or less, V: 0.04% by mass or less, and Al: 0.04% by mass or less.

P _BS = [B] × [S] × 10 ⁵

P _MT = [Mn] × [Ti] × 10 ²

Here, [] means content (mass%) in the wire of the element.

In this solid wire for carbon dioxide gas welding, it is preferable to contain at least 1 type selected from the group which consists of Mo: 0.25 mass% or less, Cr: 0.25 mass% or less, and Ni: 0.25 mass% or less. In addition, the wire surface of the MoS ₂ is preferably present from 0.01 to 1.00g per wire 10㎏.

MEANS TO SOLVE THE PROBLEM The present inventors discovered the following fact as a result of studying the relationship between the wire protrusion length, the transition form of a volume, and the penetration depth. In the constant amount of wire supply, when the protruding length is increased, the electrical resistance between the wire tip and the conduction point in the chip becomes high, so that it is easy to melt due to the temperature rise, so that the welding current supplied from the welder decreases, while the welding Voltage rises. Under the conditions of decreasing the welding current and increasing the welding voltage, the volume at which the wire tip melts and falls to the welding portion has a small arc reaction force and a long transition space (arc length), so that a large particle full globule It is easy to become transition. The directivity of the arc is weakened, and the area of the concentric circular volume drop region around the wire is enlarged. In addition, the transition period is also long, the arc force applied to the base material is weakened, and the penetration depth becomes shallow. In order to avoid this phenomenon, the inventors have found that it is most effective to prevent complete globule volume transition, and in order to do so, it is necessary to suppress a factor that greatly increases the volume. It is Ti that most affects the size of the volume, and the smaller the Ti content in the wire, the more the volume growth is suppressed, the shorter the transition is, the more the arc concentration is increased, the area of the volume drop area is reduced, and the penetration Deepens.

1 is a graph showing the relationship between the Ti content, the wire protrusion length and the penetration depth by taking the wire protrusion length (mm) on the horizontal axis and the penetration depth (mm) on the vertical axis. However, the wire supply amount is 10 m / min. As shown in FIG. 1, the penetration depth decreases as the wire projection length is longer, but when the wire projection length is the same, the penetration depth increases as the Ti content decreases.

In addition, Ti oxide is a slag source, and by reducing the amount of Ti than before, the problem caused by slag deposition can be reduced.

On the other hand, Ti has a strong affinity with nitrogen, prevents the occurrence of blow holes by combining with nitrogen at the time of shield failure, and prevents metal embrittlement. Since reducing Ti causes problems of blow hole generation and metal embrittlement, optimization of the content of Mn and B is required to improve the penetration depth due to the reduction of Ti and to offset the problem of blow hole generation and metal embrittlement. It was done.

The reason for component addition and the reason for composition limitation of the solid wire for carbonic acid gas welding of this invention are demonstrated below.

"C: 0.03-0.10 mass%"

C is an important additional element for securing strength, but if it is less than 0.03% by mass, necessary strength cannot be secured at the time of heat input between high heat input and high pass. For this reason, C is 0.03 mass% or more, Preferably you may be 0.05 mass% or more. On the other hand, when C is excessively added, hot cracking occurs easily. Moreover, when C is excessively added, the amount of sputter generation also increases due to the CO explosion phenomenon in the arc atmosphere, and the arc stability deteriorates. Moreover, when there is much C content, the intensity | strength of a weld metal will become excessive and toughness will fall inversely. When C content exceeds 0.1 mass%, since these effects become remarkable, an upper limit is made into 0.1 mass%.

`` Si: 0.67 to 1.00 mass% ''

Si is mainly added to secure strength and to prevent pore defects caused by deoxidation. In addition, addition of Si increases the amount of slag, but improves slag peelability. These effects are effective at Si content of 0.67 mass% or more. If Si content is less than 0.67 mass%, slag peelability is bad and an arc will become unstable. The minimum with more preferable Si is 0.75 mass%. On the other hand, when Si is excessively added exceeding 1.00 mass%, the amount of slag will increase excessively, arc stability will deteriorate, and toughness value will fall. For this reason, the upper limit of Si is made into 1.00 mass%.

`` Mn: 1.81-2.50 mass% ''

Mn has the effect of deoxidizing the weld metal, increasing the strength of the weld metal, and obtaining the weld metal having high toughness. In the robot system with a narrow improvement countermeasure, the maximum wire protrusion length is set long, and blow holes and deterioration of toughness are likely to occur due to poor shielding. can do. For this purpose, Mn content needs to be added at least 1.81 mass% or more. On the other hand, when Mn content exceeds 2.50 mass%, slag amount increases and slag peelability falls. As a result, the arc stability also deteriorates. In addition, as described later, the upper limit of Mn can be further lowered depending on the relationship with the Ti amount.

`` S: 0.006-0.018 mass% ''

The addition of S reduces the surface tension of the molten paper, and reduces the physical irregularities during solidification to smooth the surface of the weld metal. Thereby, slag peelability can be improved. When S is less than 0.006 mass%, such an effect does not appear, and arc stability deteriorates due to poor peelability. On the other hand, even if S is added exceeding 0.018 mass%, the effect of improving the surface shape of a weld metal becomes saturated, and high temperature cracking generate | occur | produces easily. In addition, the slag forms a particle, prevents melting due to the arc, causes partial arc instability, and also reduces toughness. Therefore, the upper limit of S is 0.018 mass%. Moreover, as mentioned later, the upper limit of S is suppressed lower by the relationship with B amount.

`` Ti: 0.100 to 0.150 mass% ''

Ti has the effect of improving the arc stability in the high current region. Generally, there are many wires which add about 0.20 mass% of Ti. One of the characteristics of the wire composition of this invention is that Ti content is lower than a general thing. If Ti is less than 0.100 mass%, arc stability deteriorates and the amount of sputter generation increases. Therefore, Ti should be added 0.100 mass% or more. In addition, when the Ti content is increased, the penetration depth decreases due to the above-described variation in the volume transition form, and the penetration failure easily occurs when the wire protrusion length is long. When Ti content exceeds 0.150 mass%, it will become a full globule volume transition and a penetration defect will arise, and therefore an upper limit shall be 0.150 mass%. In addition, as described later, the upper limit of the Ti content is further lowered depending on the relationship with the Mn content. In the case of robot welding, since the optimum voltage and the welding speed can always be optimally set, the arc stability does not deteriorate even if the Ti content is lowered.

"B: 0.0015-0.0070 mass%"

B has the effect of improving the strength and toughness by miniaturization of the crystal grains of the weld metal by addition of a small amount. When B content is less than 0.0015 mass%, the improvement effect of the strength and toughness of a weld metal does not appear, and these mechanical characteristics become inadequate. For this reason, B shall be 0.0015 mass% as a lower limit. On the other hand, when B is excessively added exceeding 0.0070 mass%, hot cracking will generate easily. Therefore, B content makes 0.0070 mass% an upper limit. Moreover, the upper limit of B content is suppressed still more by relationship with S amount.

`` Cu: 0.10 to 0.45 mass% ''

Cu becomes easy to generate a high temperature crack by excessive addition, and changes the property of slag and deteriorates peelability. As a result, arc stability deteriorates. It is not necessary to actively add Cu to the wire element, and most of it is added as Cu powder in the copper plating applied to the wire surface in order to improve the electrical conductivity, rust resistance, freshness, and designability. At a plating amount equal to or less than the amount of Cu converted to 0.1% by mass, the film thickness of the plated film is excessively thin, resulting in poor electrical conductivity, resulting in arc instability, and increased sputtering. On the other hand, when Cu content exceeds 0.45 mass%, since high temperature crack and slag peelability become a problem, the upper limit of Cu shall be 0.45 mass%. On the other hand, Cu is taken as the sum total of the thing contained in a wire rod and the copper plating part.

_{"P BS ≤10 (P BS = [} B] × [S] × 10 5) "

Both B and S are elements that cause high temperature cracks, and the content of B and S must be separately defined, and it is necessary to prevent high temperature cracks by regulating both elements in association with each other. That is, since hot cracking tends to occur in the welding process of narrow improvement, it is necessary to care about crack prevention more than before, and it is necessary to regulate these content of B and S independently, and to mutually regulate. .

2 is a graph showing the relationship between the occurrence of cracking and the like and the S and B content by taking the S content on the horizontal axis and the B content on the vertical axis. As shown in Fig. 2, as a result of experimental studies by the inventors of the present invention, in the range of P _BS > 10, although both B and S are in the prescribed range in the present invention, since both elements are in a high content range, there is no cracking. I figured this out. Therefore, when the correlation parameter P _BS is defined as [B] × [S] × 10 ⁵ ([B], [S] represents B content (mass%) and S content (mass%) in the wire, respectively). The P _BS needs to be 10 or less.

`` P _MT ≤32 (P _MT = [Mn] × [Ti] × 10 ² ) ''

Mn and Ti are the main generating elements of slag, and in addition to defining the contents of Mn and Ti individually, it is necessary to prevent excessive slag generation by regulating both elements to have correlation with each other.

3 is a graph showing the relationship between the amount of slag and these Mn and Ti contents by taking Mn content on the horizontal axis and Ti content on the vertical axis. As shown in Fig. 3, in the range of P _MT > 32, even if both Mn and Ti are within the prescribed range of the present invention, since both elements have a high content, the amount of slag generated increases and the slag peelability deteriorates. The inventors found out that the stability of the deteriorated. Moreover, when slag amount increases, it is necessary to remove slag frequently, and operation efficiency will fall. Therefore, when the correlation parameter P _MT is defined as [Mn] × [Ti] × 10 ² ([Mn], [Ti] represents Mn content (mass%) and Ti content (mass%) in the wire, respectively). It is necessary to make P _MT 32 or less.

`` P: 0.020 mass% or less ''

P is one of the main elements causing hot cracking, and it is not necessary to actively add P. Therefore, the upper limit of P is set to 0.020 mass% as an upper limit in which high temperature cracking does not become a problem.

"Nb: 0.04 mass% or less, V: 0.04 mass% or less, Al: 0.04 mass% or less"

Nb, V, and Al reduce the toughness of the weld metal under low heat input welding conditions. For this reason, it should be avoided that these elements are actively added, and as an upper limit of the allowable range which can ignore toughness deterioration, the upper limit of these elements shall be 0.04 mass%, respectively.

"Mo: 0.25 mass% or less, Cr: 0.25 mass% or less, Ni: 0.25 mass%"

Since Mo, Cr, and Ni improve the hardenability of a weld metal and raise strength, it is preferable to add actively. These Mo, Cr, and Ni can maintain moderate strength even at higher heat input and interpass temperatures. Although addition of these elements does not need to provide especially a minimum, the effect becomes remarkable when adding at least 1 mass of 0.05 mass% or more of Mo, Cr, and Ni. On the other hand, when these elements are added exceeding 0.25 mass%, the microstructure of a weld metal will martensite, and toughness will fall. Therefore, when adding these elements, you may be 0.25 mass% or less, respectively.

"MoS _{2 on} wire surface: 0.01 to 1.00 g per 10 kg of wire"

Wire feedability greatly affects slag peelability. The stable supply of the wire makes the formation of the molten pool more stable, the thickness of the produced slag becomes uniform, and the deformation of the heat shrinkage acts uniformly, thereby easily peeling off the entire surface. MoS ₂ on the surface of the wire lowers the fusion at the feed point between the chip and the wire, leading to an improvement in wire supplyability. As a conventional wire supplying improvement means, there is a method of overoxidizing depending on the grain boundary of the wire surface. However, this method has a drawback that the amount of O is excessive and the amount of slag increases. On the other hand, the coating of MoS ₂ is compared to the third improvement means, because they do not increase the amount of slag is suitable as the wire feed means improvement of the wire of the present invention. This effect is effective by attaching 0.01 g or more of MoS ₂ per 10 kg of wire. On the other hand, if MoS ₂ is attached in excess of 1.00 g per 10 kg of wire, deposition in the supply system starts, and conversely, poor supply due to blockage of MoS ₂ occurs, affecting slag properties, and exfoliation properties. Lowers. As a result, arc stability deteriorates. Therefore, it is preferable to have 0.01-1.00 g of MoS ₂ per 10 kg of wire on the wire surface.

(Example)

EMBODIMENT OF THE INVENTION Hereinafter, in order to demonstrate the effect of this invention, the result of having carried out the welding test about the wire of the Example and the wire of the comparative example which departs from the scope of this invention is demonstrated. 4 (a) to 4 (c) are diagrams showing a welded test body shape and an improved shape. Fig. 4 (a) is a cross-sectional view showing an enlarged portion, Fig. 4 (b) is a front view of the test body, and Fig. 4 (c) is a side view. The diaphragm 1 is arrange | positioned with the surface perpendicular, the annular steel pipe 3 is arrange | positioned so that the axis may be horizontal, and the cross section of the annular steel pipe 3 may face the diaphragm 1. The cross section of the annular steel pipe 3 is rounded, and a Le-shaped improvement is formed between the diaphragm 1. Moreover, the cylindrical backing strip 2 is arrange | positioned at the inner surface of the annular steel pipe 3. And this improved part was main-welded by the welding torch 4.

Table 1 below shows the welding conditions. In addition, Table 2 below shows the combination of the steel sheets of the diaphragm 1, the steel pipe 3 and the support 2, and Table 3 shows the composition (mass) of the diaphragm 1, the steel pipe 3 and the support 2 %). The welding test body shown in FIG. 4 was welded using the robot welding system for steel-frame construction marketed under the welding conditions shown in Table 1. FIG. In addition, the diaphragm 1 and the steel pipe 3 are blast furnace materials, whereas the support 2 is a commercially available converter material, and the support 2 has a high nitrogen content and weldability. Will fall. Although the improvement angle is generally 35 ° and the root gap is 7 mm, in this welding test, the improvement angle is 30 ° and the root gap is a narrow improvement construction of 5 mm. And the peelability of slag after completion | finish of welding was computed by digital image processing, the slag amount was measured, and the tensile test and the Charpy impact test were done as an index of the strength and toughness of the weld metal. In addition, the stability of the arc under welding and the amount of sputter generation were recorded. In addition, the lack of penetration and the occurrence of hot cracking were examined by an ultrasonic flaw test.

Table 4 below shows the wire compositions (mass%) of the examples and the comparative examples. In addition, Table 5 below shows the test results of the welding test. On the other hand, in the composition of Table 4, "<0. ***" shows that the analysis result of a composition is a value less than the lower limit of general analysis precision, and does not contain industrially.

The evaluation method of each characteristic shown in Table 5 is as follows. About the peelability evaluation method of slag, evaluation of peelability and slag amount was measured only on condition 1 (refer Table 2) in which the plate | board thickness of a steel pipe is thin. In addition, it was confirmed that the welding wire having good slag peelability under condition 1 was similarly good under condition 2 as well. When the welding start point entered the welding of the final pass, 100 mm front and rear and 200 mm in total were photographed around the point returned 90 ° from the wire (see Figs. 4 (b) and (c)). Next, the bead appearance photograph was binarized into (a) the part where the slag naturally peeled off, and (b) the part with the slag attached, and the distribution was calculated | required. The sum total of each pixel was computed by image analysis software, and slag peeling rate (%) was calculated | required by (a) / ((a) + (b)) * 10O. It was judged that slag peelability was favorable that the slag peeling rate is 15% or more.

Next, about the amount of slag, all the slag was collect | recovered and the weight was measured including the thing which peeled naturally after bead appearance photographing. The slag amount was made into favorable thing that this slag amount is 12 g or less.

In the tensile test and the Charpy impact test of the weld metal, in condition 2 (see Table 2), A2 (parallel diameter 6 mm) and standard test piece (10 mm angle) of JIS Z3111 are shown in FIGS. 5 and 6, respectively. It was taken from the site and provided for testing. In addition, the tensile test made 20 degreeC of room temperature, and the Charpy impact test made 0 degreeC and 3 bone averages an evaluation value. Tensile strength was 490 N / mm <2> or more, and the Charpy impact test made the average 70J or more pass.

Arc stability is based on the evaluation of the action during welding, and it was judged that the case where the slag prevented the generation of an arc and was not disturbed was especially favorable. Moreover, even if the dizziness of the arc resulting from the wire supply failure was made, it was set as the failure.

Sputter generation amount collect | recovers the sputter | spatter adhering to a shield nozzle after completion | finish of welding on condition 1 (refer Table 2), and weighs it. The sputter generation amount was determined to be 6 g or less.

Welding machine Steel frame welding robot Welding power supply, polarity DC motor, reverse polarity Shield gas CO ₂ , flow rate 25 liters / min Wire diameter 1.2 mm Heat 40kJ / cm max Interpass temperature 350 ℃ max posture Downward Wire extrusion length 27 to 35 mm Slag removal Condition 1: no, condition 2: no Sputter with nozzle removal and cleaning Condition 1: no, condition 2: no

Diaphragm Steel pipe Stand Condition 1 (thin plate) SN490C Plate Thickness 25mm × 450mm Angle STKN490B thickness 16 mm x outer diameter 350 mm SN490A thickness 9mm X outer diameter 334mm Condition 2 (thick plate) SN490C Plate Thickness 75mm × 800mm Angle STKN490B thickness 60mm X outer diameter 700mm SN490A thickness 9mm X outer diameter 640mm

As shown in Table 5, in Examples 1 to 18 of the present invention, since the composition range of each component is within the range defined by the present invention, the peelability of slag, the amount of slag, the strength of the weld metal, the toughness, the stability of the arc, Low sputterability, penetration performance and crack resistance are all good, and excellent welding workability and excellent mechanical properties of the weld metal are obtained.

On the other hand, Comparative Examples 19 to 50 departed from the scope of the present invention, but in Comparative Example 19, C was too low, and the strength of the weld metal was insufficient. In Comparative Example 20, C was excessive, hot cracking occurred in the weld metal, excessive strength, and low toughness. Moreover, since many sputters and the arc stability were bad, continuous weldability also deteriorated. In Comparative Example 21, Si was too low, the strength of the weld metal was insufficient, the slag peelability was also poor, the arc was unstable due to the interference of the slag, and the continuous weldability was deteriorated. In addition, blowholes also occurred due to lack of deoxidation. In Comparative Example 22, the Si was excessive, the toughness of the weld metal was insufficient, the amount of slag was excessively hindered, the arc was unstable, and the continuous weldability was deteriorated. In Comparative Example 23, Mn was too low, toughness was low, and blow holes were also generated due to lack of deoxidation. In Comparative Example 24, Mn was excessive, the slag amount was large, and the peelability was also bad. In addition, interruption of slag caused arc instability, resulting in deterioration of continuous weldability. In Comparative Example 25, since Ti was excessively large, the amount of sputtering was generated, the arc stability was poor, and the shield nozzle was easily clogged, so that continuous weldability was deteriorated. In Comparative Examples 26 and 27, since Ti was excessive and the volume shift became a full globule shift, a large number of poor penetration occurred. In Comparative Example 28, each of the components of Mn and Ti satisfies the prescribed range, but because the parameter P _MT became too large, the amount of slag was large and the peelability was also bad. In addition, interruption of slag caused arc instability, resulting in deterioration of continuous weldability. In Comparative Example 29, S was excessively low, the peelability of slag was bad, the arc was unstable due to the interference of the slag, and the continuous weldability was deteriorated. In Comparative Example 30, S was excessive, low toughness and high temperature cracking also occurred. Although slag had good peelability, what adhered was granulated, and the thickness increased, and the stability of the arc was impaired. As a result, continuous weldability deteriorated.

In Comparative Example 31, each component of S and B satisfied the prescribed range of the present invention, but because the parameter P _BS was excessively large, crack resistance was impaired and cracking occurred. In Comparative Example 32, P was excessive, low toughness and high temperature cracking also occurred. In Comparative Example 33, Cu was too small and the thickness of the copper plating layer was thin, resulting in poor energization, resulting in a large number of microfusions, unstable arcing, and increased sputtering. In Comparative Example 34, Cu was excessive, hot cracking occurred, slag peelability was bad, and the arc was unstable due to the interference of slag, resulting in deterioration of continuous weldability. Comparative Example 35 lacked B and lacked strength and toughness. In Comparative Example 36, B was excessive and hot cracking occurred.

In Comparative Example 37, each element of Mn, Ti, B, and S satisfies the prescribed range of the present invention alone, but the parameters P _MT and P _BS exceed the prescribed range of the present invention. For this reason, the amount of slag was large and the slag peelability was also bad. In addition, the arc became unstable due to the interference of the slag, resulting in deterioration of continuous weldability and high temperature cracking. Nb, V, and Al were excessive in Comparative Examples 38 to 40, respectively, and the toughness decreased. In Comparative Examples 41 to 43, the Mo, Cr, and Ni were respectively excessive, and the strength was improved, but the strength was excessive, and conversely, the toughness decreased. Comparative Example 44 is MoS ₂ The amount of deposition was excessive and MoS ₂ was clogged with supply systems such as conduit liners and the wire supply became very unstable. As a result, the arc stability was impaired, the slag distribution became nonuniform, adversely affected, and the slag peelability was lowered. As a result, continuous weldability deteriorated by the interference of slag.

In Comparative Example 45, Ti is excessive, S is excessive, and B is no addition. For this reason, since a solution transition became full globule by Ti excess, many penetration defects generate | occur | produced. Moreover, slag peelability was also bad because S is too small. Moreover, the arc became unstable due to the interference of the slag, and the continuous weldability was deteriorated. In addition, since B was not added, strength and toughness were insufficient. In Comparative Example 46, Ti is excessive and S and Mn are excessive. Due to the excess of Ti, the volume transition becomes a full globule transition, and a large number of defects in penetration occurred. Moreover, since S was underexposure, peelability was also bad. The slag interfered and the arc became unstable and the continuous weldability deteriorated. Since Mn is too small, strength and toughness were insufficient, and blowholes also occurred due to lack of deoxidation. In Comparative Example 47, C is excessive, Mn is insufficient, and Ti and B are not added. For this reason, Mn deficiency and B no addition resulted in lack of strength and toughness, and blowholes also occurred due to deoxidation deficiency. The high temperature crack generate | occur | produced by C excess, and also Ti addition did not increase, there were many sputter | spatters, and arc stability was bad.

In Comparative Example 48, Ti, P _MT and Mo are excessive, and Si and S are insufficient. For this reason, since the volume transition became full globule transition by Ti excess, many penetration defects generate | occur | produced. In addition, slag peelability was also bad because Si and S were excessively small. The interruption of the slag caused the arc to become unstable, resulting in deterioration of continuous weldability. In addition, the toughness was insufficient due to the excess of Mo. In addition, blowholes also occurred due to lack of deoxidation due to lack of Si. In Comparative Example 49, Si and S are excessive, Ti is insufficient, and B is additive. Toughness fell and the intensity | strength was low by B no addition. Since Si and S were excessive, the amount of slag was large, and granulation was performed to impair the arc stability. As a result, continuous weldability deteriorated. In addition, a large number of sputters occurred due to the lack of Ti. Since S is excessive, high temperature cracking also occurred. In Comparative Example 50, Si was insufficient, B was excessive, and P _BS was excessively large. Due to the lack of Si, the strength of the weld metal was insufficient, the slag peelability was poor, and the arc became unstable due to the interference of the slag, resulting in deterioration of the continuous weldability. Blow holes also occurred due to lack of deoxidation due to lack of Si. In addition, since _PBS was excessively large, high temperature cracking also occurred.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the influence which Ti amount and wire protrusion length in a wire component have on penetration depth.

2 is a view showing the range of B and S in the present claim.

3 is a view showing the range of Mn and Ti in the present claim.

It is a figure which shows a weld test body shape and an improved shape.

It is a figure which shows the sampling position of a weld metal tensile test piece.

It is a figure which shows the sampling position of a weld metal Charpy impact test piece.

Claims (3)

Solid wire for carbon dioxide welding, C: 0.03 to 0.10 mass%, Si: 0.67 to 1.00 mass%, Mn: 1.81 to 2.50 mass%, S: 0.006 to 0.018 mass%, Ti: 0.100 to 0.150 mass%, B: 0.0015 to 0.0070 mass%, plating powder Cu containing 0.10 to 0.45% by mass, Remainder is Fe and inevitable impurities, The parameters P _BS and P _MT represented by the following formula satisfy P _BS ≤10 and P _MT ≤32, Solid wire for carbonic acid gas welding regulated by P: 0.02 mass% or less, Nb: 0.04 mass% or less, V: 0.04 mass% or less, Al: 0.04 mass% or less. P _BS = [B] × [S] × 10 ⁵ P _MT = [Mn] × [Ti] × 10 ² (Where [] means the content (mass%) in the wire of the element) The method of claim 1, The solid wire for carbonic acid gas welding containing 1 or more types chosen from the group which consists of Mo: 0.25 mass% or less, Cr: 0.25 mass% or less, and Ni: 0.25 mass% or less. The method according to claim 1 or 2, The MoS ₂ on the wire surface, the wire O.01 to 1.00g present solid wires for carbon dioxide gas welding, which per 10㎏.

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