CN101380704A - Solid wire for gas-shielded arc welding - Google Patents

Abstract

To provide a solid wire for gas-shielded arc welding which can provide stable bead formation and a welded joint having low high temperature crack sensitivity, and excellent fatigue strength, tensile strength and toughness, even in high speed welding at >=1.0 m/min in the welding of a steel sheet having a sheet thickness of 0.6 to 10 mm. The solid wire comprises, by mass, 0.02 to 0.15% C, 0.50 to 1.50% Si, 1.00 to 3.00% Mn, <=0.025% P and 0.020 to 0.150% S, and further comprising one or two kinds selected from 0.005 to 0.5% Nb, 0.005 to 0.5% V, 0.010 to 0.5% Al, 0.005 to 0.5% Cr, 0.005 to 0.5% Ni and 0.0010 to 0.0100% B, and the balance Fe with inevitable impurities.

Description

The solid core welding wire that is used for gas shielded arc welding

The application is to be on June 15th, 2006 applying date, and application number is 200610092535.1, and denomination of invention is divided an application for the application of " solid core welding wire that is used for gas shielded arc welding ".

Technical field

The present invention relates to be used for the solid core welding wire of the gas shielded arc welding of for example zero carbon steel of automobile sheet metal uniform thickness 0.6～10mm for example and high-strength steel sheet.

Background technology

The gas shielded arc welding welded structure must have higher quality, and its production must provide work more completely to save and higher efficient.In auto industry, for example use the welding full automation of welding robot to be pulled to the foreground, in present commodity production line, weld with about 1.0m/ minute speed.Need welding more expeditiously under higher speed.

The sheet metal structure has and the corresponding to important technology chance of global environment problem.In them, in auto industry, in order to reduce weight, thereby improve fuel efficiency, press for and reduce the specification (reduction size) of using high-strength steel sheet.But, although the load stress on the welding point increases, because compare with common base metal, the fatigue strength of welding point does not increase, the welded articles that obtains equates with conventional mild steel, so can not show the original fatigue strength of high-strength steel sheet material.

When using the conventional fillers metal material when surpassing 1.3m/ minute weld at a high speed, will form for example irregular bead such as undercutting bead and bulge bead in order further to improve welding efficiency.In addition, because the extruding precision of workpiece changes, so the root gap of weld of lap-fillet welds point (rootopening) often changes, if carry out the welding of high speed on greater than the root gap of 1.9mm, will take place for example to grill thoroughly and weld defect such as perforation.Therefore, need even when high-speed welding, also can stably produce the welding material of the wide bead of bead and generation energy cross-over connection root gap strongly.

In open (JP-A) the 05-305476 communique of Japanese unexamined patent, can find the conventional solid core welding wire of the steel-sheet gas shielded arc welding that is used to have 6mm or littler thickness.This solid core welding wire will improve welding processing and the welding quality with the thick thin slice of 1.0m/ minute or higher high-speed welding 6mm, the carbon (C) that contains 0.02～0.10 quality %, 0.8 the silicon of～1.2 quality % (Si), 1.0 the manganese of～1.8 quality % (Mn), 0.020 quality % or lower phosphorus (P), 0.020 the sulphur of～0.100 quality % (S), 0.005 quality % or lower aluminium (Al), 0.0070 quality % or lower oxygen (O) and 0.00790 quality % or lower nitrogen (N), surplus is iron (Fe) and unavoidable impurities, and wherein Mn is 1.2～1.8 with the ratio (Mn/Si) of Si.This technology forms property by the bead that adds a large amount of sulphur and improve in the high-speed welding with the surface tension of regulating motlten metal.

The sheet metal that uses conventional welding material high-speed welding to make underlying metal often produces the projection welding road, does not even cause irregular bead.Because the stress of toe place of welding is concentrated, such projection welding road usually causes fatigue strength to reduce.Therefore, must weld with the speed of welding lower than routine techniques.Therefore, be applied even more extensively in these structures, Welding Structure that high-fatigue strength can be provided and the welding material of keeping satisfied welding efficiency need be provided in order to make high strength steel.

The welding material of giving compression stress to welding point is commonly used to improve the fatigue strength of contact.Particularly, can reduce residual stress by reducing Ms (martensite start) point (after this being called " Ma Shi point (Ms point) "), so that just can utilize transformation to expand at low temperature.For example, JP-A 11-138290 communique proposes a kind of utilization and has the typical predetermined composition of C, Cr, Ni, Si, Mn, Mo and Nb content with the welding material of Ma Shi point control at 250 ℃～170 ℃.

But above-mentioned routine techniques has following shortcoming.The sulphur of describing in the JP-A 05-305476 communique (S) that is added in the solid core welding wire is a kind of element of taking certain amount just to change interfacial tension and molten metal flow and can realize high-speed welding significantly.But sulphur impels fire check.In the weld metal of the filling metal material that uses compound 20 .02% or more sulphur, this trend (impelling fire check) is tangible.Especially, when on greater than the root gap of the variation of 1.0mm with 1.0m/ minute or higher when welding at a high speed, fire check takes place more frequently.

Since along with the increase of sulfur content, the sulfide chap, so sulphur not only causes fire check, and the intensity and the toughness of attenuating material.According to the G of Japanese Industrial Standards (JIS) 4804 sulfur-bearing shear-steel materials, a kind of cutting steel by containing a large amount of sulphur (SUM 24L contains the sulphur of 0.26～0.35 quality %), has improved machinability.But in needing the intensity of certain level, toughness and other mechanical weld metal, sulfur content generally minimizes to 0.03% or lower, and this is because the existence of sulphur is very harmful to them.Therefore, the solid core welding wire of describing in the JP-A 05-305476 communique shows higher a little fire check sensitiveness and lower intensity and toughness than common welding wire.

The welding material of describing in the JP-A 11-138290 communique contains the alloying metal of mass expensive, and for example Cr and Ni show the calenderability of going on business when as solid core welding wire, are the welding materials of very expensive (expensive).Because this welding material has high viscosity,, welds on the needed high-speed welding this welding material so can not being applied to sheet metal.It also can prevent to increase the droplet transfer of splash (welding slag).Like this, this material has poor application to actual welding wire.

Summary of the invention

In these cases; an object of the present invention is to provide a kind of solid core welding wire that is used for gas shielded arc welding; even in 1.0m/ minute or higher high-speed welding, also can stably form bead; and in steel-sheet welding, can produce the welding point of fatigue strength, tensile strength and toughness with low fire check sensitiveness and excellence with 0.6～10mm thickness.

Particularly, a first aspect of the present invention provides a kind of solid core welding wire that is used for gas shielded arc welding, based on the gross mass of described solid core welding wire, contain silicon (Si), 1.00～3.00 quality % of carbon (C), 0.50～1.50 quality % of 0.03～0.15 quality % manganese (Mn), 0.020～0.150 quality % sulphur (S) and be selected from least a in the group of forming by the cerium (Ce) of the lanthanum (La) of the zirconium (Zr) of the titanium (Ti) of 0.01～0.20 quality %, 0.01～0.20 quality %, 0.01～0.05 quality % and 0.01～0.05 quality %; Surplus is iron and unavoidable impurities, and wherein phosphorus (P) is 0.025 quality % or lower as the content of unavoidable impurities, and " A " value of determining according to following equation 1 is 100 or bigger;

Equation 1

$A=\frac{\left[\mathrm{Mn}\right]+20\&times;\left[\mathrm{Ti}\right]+25\&times;\left[\mathrm{Zr}\right]+50\&times;\left[\mathrm{La}\right]+50\&times;\left[\mathrm{Ce}\right]}{\left[S\right]}$

Wherein [Mn], [Ti], [Zr], [La], [Ce] and [S] represent Mn, Ti, Zr, La, Ce and the S content (quality %) of welding wire respectively.

Based on the gross mass of described solid core welding wire, solid core welding wire of the present invention has specific sulphur (S) content of 0.020～0.150 quality %, and this makes motlten metal seldom flow to the back, flows to width more.Described solid core welding wire also has manganese (Mn) content of 1.00～3.00 quality %.This makes the MnS crystallization, thereby described solid core welding wire has the eutectic temperature of rising and the fire check sensitiveness of reduction.In addition, solid core welding wire contains at least a in the group of being made up of the Ti that tends to form sulfide, Zr, La and Ce of being selected from of appropriate amount.This causes forming the sulfide that contains these elements, has high fusing point, and sulphur content is dispersed in the matrix phase.Thereby prevent to form sulfide at crystal boundary.In addition, in solid core welding wire, " A " value of determining according to equation 1 is set at 100 or bigger, thereby can stably form bead in high-speed welding, even in the welding of high-strength steel sheet, also can obtain having the fire check sensitiveness of reduction and the welding point of the fatigue strength of excellence.

Solid core welding wire can have 1.50 quality % or higher manganese (Mn) content.This can reduce fire check sensitiveness significantly.

Solid core welding wire also has 0.040 quality % or higher sulphur (S) content.This can more stably form bead in high-speed welding, improve fatigue strength.

The present invention further provides a kind of solid core welding wire that is used for gas shielded arc welding in second aspect, based on the gross mass of described solid core welding wire, contain the carbon (C) of 0.02～0.15 quality %, 0.50 the silicon of～1.50 quality % (Si), 1.00 the manganese of～3.00 quality % (Mn), 0.020 the sulphur of～0.150 quality % (S), 0.005 the niobium of～0.5 quality % (Nb), with the vanadium (V) that is selected from by 0.005～0.5 quality %, 0.010 the aluminium of～0.5 quality % (Al), 0.005 the chromium of～0.5 quality % (Cr), 0.005 the nickel of～0.5 quality % (Ni), at least a in the group of forming with the boron (B) of 0.0010～0.0100 quality %; Surplus is iron and unavoidable impurities, and wherein phosphorus (P) is 0.025 quality % or lower as the content of unavoidable impurities.

Because the content of sulphur and other alloying element is regulated suitably, so solid core welding wire of the present invention even also can stably form bead in high-speed welding can produce the welding point of fire check sensitiveness with reduction and excellent fatigue strength, tensile strength and toughness in the welding of high-strength steel sheet.

In addition, the present invention provides a kind of method of carrying out gas shielded arc welding in the third aspect, comprises using the above-mentioned solid core welding wire welding that is used for gas shielded arc welding to have the step of the high-strength steel sheet of 0.6～10mm thickness.

According to the present invention, even in high-speed welding, also can stably form bead, even in the welding of high-strength steel sheet, also can obtain having the welded contact of the fire check sensitiveness and excellent fatigue strength, tensile strength and the toughness of reduction with 0.6～10mm thickness.

The present invention can form the few wide suitable bead with excellent electro-deposition coating of welding slag.This advantage is remarkable especially in the sheet metal with 0.6～10mm thickness welds with 1.0m/ minute or higher high speed.Therefore, in the steel-sheet high-speed welding, can form and have stable shaped bead, can obtain having the welding point of excellent fatigue strength.In addition, fire check sensitiveness can be reduced, suitable intensity and toughness can be guaranteed.

From the following description of the preferred version of reference accompanying drawing, will obviously see other purposes of the present invention, characteristics and advantage.

Description of drawings

Fig. 1 is the figure of toe that takes the welding of pin welding point; With

Fig. 2 A is the sectional view of expression test pieces sample position, and Fig. 2 B is a plane of representing how to prepare the test pieces of fishbone cracking test.

The specific embodiment

For after reaching the studying in great detail of described purpose, the inventor finds to take place following phenomenon in the steel-sheet welding with 0.6～10mm thickness: the reduction of the fire check that the formation of irregular bead, sulphur are induced and the fatigue strength of weld metal, intensity and toughness.

Motlten metal on the fusion weld pool surface of rule bead is drawn into the low temperature part from high-temperature part to the back, and the surface tension gradient that suction intensity and temperature difference produce and the length of fusion weldpool are proportional.In 1.0m/ minute or higher high-speed welding, the fusion weldpool prolongs on the sealing wire direction, and molten metal flow speed uprises significantly.This is one of factor that produces irregular bead such as undercutting bead and bulge bead for example.

The original scope of the solidification temperature of weld metal is considerably narrow, but even the trace sulphur also work to widen the solidification temperature scope.In this stage, along with the curing of matrix phase, sulphur is enriched in the residual melt in the dendrite array (dendritic array), because the eutectic of residual melt solidifies, the final stage crystallization of solidifying at matrix phase sulfide.The eutectic temperature of Fe-FeS is more much lower than the fusing point of iron.In the final stage of solidifying, emanate out at the crystal boundary place this low melting point liquid phase and compound produce fire check.

Along with the increase of sulfur content, sulphur not only produces fire check, and makes the sulfide chap, thereby reduces the percentage elongation and the toughness of material.For example according to the steel such as sulfur-bearing shear-steel of the G of Japanese Industrial Standards (JIS) 4804, a kind of cutting steel has improved machinability (SUM 24L contains the sulphur of 0.26～0.35 quality %) by containing a large amount of sulphur.But in the weld metal that needs the percentage elongation of certain level, toughness and other mechanical performance, sulfur content generally minimizes to 0.03% or lower, and this is because the existence of sulphur is very harmful to them.

In addition, can to make the fatigue limit of underlying metal than ordinary steel low for the fatigue limit of the welding point of high strength steel.This mainly is to be produced by the stress raisers that the welding toe takes place.Fig. 1 is the figure that takes the welding toe of pin welding point.In joint shown in Figure 1, underlying metal (following sheet) 1a and another kind of underlying metal (top sheet) 1b upwards weld below oblique.The inventor finds that stress concentrates the shape of promptly welding toe along with the shape of the crossing part in the surface of underlying metal 1a and the surface of bead 2 to change significantly, can increase the fatigue strength of welding point greater than 0.3mm by making toe diameter ρ.But, protruding because bead becomes easily in the high-speed welding of high-strength steel sheet, so toe diameter ρ diminishes, can not show the original fatigue strength of high-strength steel sheet fully.

Sulphur (S) is the element that reduces the surface tension of motlten metal and change the surface tension gradient that produces owing to temperature difference.Therefore, the inventor has successfully made motlten metal seldom flow to the back direction and flow to width morely by regulating and stipulate the content of sulphur and other element.Like this, they have found even also can produce in high-speed welding has the composition that prevents the bead that acts on to undercutting and bulge.Particularly, based on the gross mass of welding wire,, can make motlten metal seldom flow to the back direction and flow to width morely by sulfur content being set in 0.020～0.150 quality %.In the high-speed welding of high-strength steel sheet, this can make toe diameter ρ shown in Figure 1 is 0.3mm or fatigue strength bigger and the improvement welding point.

As above-mentioned, the adding of sulphur increases fire check sensitiveness.Can reduce the fire check sensitiveness that sulphur is induced by improving eutectic temperature.This can form by the element that sulphur is had a high affinity that adds appropriate amount has dystectic compound, realizes thereby sulphur content is dispersed in the matrix phase.Particularly, based on the gross mass of welding wire, manganese (Mn) content is set in 1.00～3.00 quality %, crystallization goes out MnS, thereby improves eutectic temperature.By at least a sulphur further can being dispersed in the matrix phase among Ti, the Zr, La and the Ce that add appropriate amount, this is because these elements play formation sulfide, thereby forms the effect of the high melting compound of sulfur-bearing.This can prevent basically at crystal boundary place formation sulfide.

In addition, making " A " value of determining according to following equation 2 by the content of regulating alloy compositions is 100 or bigger, even in the welding of high-strength steel sheet, also can obtain the stable shaped of bead, fire check sensitiveness reduces, and can obtain the welding point of fatigue strength excellence:

Equation 2

$A=\frac{\left[\mathrm{Mn}\right]+20\&times;\left[\mathrm{Ti}\right]+25\&times;\left[\mathrm{Zr}\right]+50\&times;\left[\mathrm{La}\right]+50\&times;\left[\mathrm{Ce}\right]}{\left[S\right]}$

Wherein, [Mn], [Ti], [Zr], [La], [Ce] and [S] represent Mn, Ti, Zr, La, Ce and the S content (quality %) of welding wire respectively.

Consider these discoveries, the inventor has realized the solid core welding wire that is used for gas shielded arc welding as the present invention's first scheme.This solid core welding wire even in the high-speed welding of the gas shielded arc welding of high-strength steel sheet, also can produce and have stable shaped bead and form welding point with low fire check sensitiveness and excellent fatigue strength with 0.6～10mm thickness.

As above-mentioned, along with the increase of sulfur content, fire check sensitiveness increases.At first, reduce fire check sensitiveness by preventing to form the low-melting compound FeS of main generation fire check.According to this technology, by add sulphur is had affinity element with the rising eutectic temperature, thereby the sulfide that forms is dispersed in the matrix phase, stop to form low-melting compound FeS.As second kind of solution, the element that has high hardenability by adding reduces fire check sensitiveness to disperse FeS equably thereby prevent to emanate, and this is to be lowered because of the size as the crystal grain that solidifies result's formation, thereby the surface area of crystal boundary increases.Based on these, the inventor finds that the effective content that must show these elements reduces fire check sensitiveness.

Consider these discoveries, the inventor has realized the solid core welding wire that is used for gas shielded arc welding as alternative plan of the present invention.This solid core welding wire even also can produce the bead of dimensionally stable in high-speed welding can produce the welding point that has low fire check sensitiveness and show excellent fatigability, tensile strength and toughness in the welding of high-strength steel sheet.

(1) making sulfur content is 0.020～0.150 quality %, and it is less that motlten metal is flowed on the direction overleaf, and it is more to flow on width.

(2) Mn content is set at 1.00～3.00 quality %, the MnS crystallization is gone out, improve eutectic temperature, thereby reduce crack sensitivity.

(3) by sneaking at least a in following: the chromium (Cr) of the vanadium (V) of the niobium of 0.005～0.50 quality % (Nb), 0.005～0.5 quality %, the aluminium (Al) of 0.010～0.5 quality %, 0.005～0.5 quality %, the nickel (Ni) of 0.005～0.5 quality % and the boron (B) of 0.001～0.010 quality %, increase hardenability, make crystal grain thinner.Sneak into these elements of appropriate amount, make the structure that forms as the curing result thinner, thereby increase the surface area of crystal boundary.Prevent FeS liquid phase segregation, make its dispersion, this has reduced fire check sensitiveness.Forming the FeS liquid phase on the crystal boundary and in the dendrite array, cause cracking.Because these elements make crystal boundary thinner, thereby expand when improving toughness and alleviating welding and shrink the stress of the FeS liquid phase that produces when solidifying and concentrate, so these elements also play the effect that reduces fire check sensitiveness.

(4) other element of listing in (3) prevents to form welding slag.That is, they promote to form suitable bead, and the welding slag of bead is less.Thereby these elements of appropriate amount can reduce fire check sensitiveness and guarantee suitable intensity and toughness, do not damage the advantage of such element.

The reason of stipulating the composition of welding wire of the present invention is explained as follows.Composition as the solid core welding wire that is used for gas shielded arc welding of the present invention's first scheme is at first described.

Carbon content: 0.03～0.15 quality %

Carbon (C) is the element of guaranteeing that the intensity of weld metal is required and quickening deoxidation effectively.But, based on the gross mass of welding wire, if carbon content less than 0.03 quality %, weld metal has inadequate intensity.On the contrary, if carbon content surpasses 0.15 quality %, weld metal has the toughness of reduction and the fire check sensitiveness of increase.Therefore, based on the gross mass of welding wire, carbon content is set at 0.03～0.15 quality %.

Silicone content: 0.50～1.50 quality %

Silicon (Si) be promote deoxidation to heavens, to improve hardness of steel needed and play the element of the conforming effect of improvement bead.But, based on the gross mass of welding wire, if silicone content can not obtain these advantages less than 0.50 quality %.On the contrary, if silicone content surpasses 1.50 quality %, the release property of drop and the toughness of weld metal are undermined.Therefore, based on the gross mass of welding wire, silicone content is set in 0.50～1.50 quality % here.

Manganese content: 1.00～3.00 quality %

Manganese (Mn) is the element that promotes deoxidation effectively and work the mechanical performance effect that improves weld metal as silicon.It also rises and the MnS crystallization is gone out and improves eutectic temperature, thereby reduces the effect of fire check sensitiveness.But, based on the gross mass of welding wire, if manganese content less than 1.00 quality %, fire check sensitiveness increases.On the contrary, if the manganese content of weld metal is high excessively, surpass 3.00 quality %, toughness lowers.Thereby,, manganese content is set in 1.00～3.00 quality % based on the gross mass of welding wire.Preferred settings is at 1.50 quality % or higher.

Sulfur content: 0.020～0.150 quality %

The effect of sulphur (S) landing low melt metallic surface tension force, when adding suitable amount, the fatigue strength that works to improve the bead and the uniformity between the underlying metal of welding toe place and improve welding point.But, based on the gross mass of welding wire, if sulfur content can not obtain these advantages less than 0.020 quality %.On the contrary, if when sulfur content surpasses 0.150 quality %, even regulate the content of other element, also fire check will take place.Therefore, based on the gross mass of welding wire, sulfur content is set at 0.020～0.150 quality %.Preferred settings more preferably is set in 0.060 quality % or higher at 0.040 quality % or higher.

" be selected from the group of forming by the cerium (Ce) of the lanthanum (La) of the zirconium (Zr) of the titanium (Ti) of 0.01～0.20 quality %, 0.01～0.20 quality %, 0.01～0.05 quality % and 0.01～0.05 quality % at least a "

Titanium (Ti), zirconium (Zr), lanthanum (La) and cerium (Ce) are easy fault sulphurs, thereby form the element of high fusion sulfide.Add at least a sulphur content can being dispersed in the matrix phase in these elements.But, even when being added in these elements two or more in this solid core welding wire, based on the gross mass of welding wire, if the content of every kind of element can not obtain these advantages less than 0.01 quality %.On the contrary, if Ti content or zirconium content surpass 0.20 quality %, the drop chap, the droplet transfer is disturbed, and forms welding slag excessively, thus the infringement welding processing.Therefore, if add, based on the gross mass of welding wire, the content of Ti and/or Zr is set in 0.01～0.20 quality %.If the content of lanthanum or cerium surpasses 0.05 quality %, the sulfide chap, steel-making output reduces, thereby increases cost.Therefore, if add, based on the gross mass of welding wire, the content of La and/or Ce is set in 0.01～0.05 quality %.

Phosphorus content: 0.025 quality % or lower

Phosphorus (P) pollutes steel as unavoidable impurities.It is the element that increases fire check sensitiveness, preferably reduces its content.But, based on the gross mass of welding wire, 0.025 quality % or more the phosphorus of low content be inappreciable.Therefore, based on the gross mass of welding wire, P content is controlled at 0.025 quality % or lower.

" A ": 100 or bigger

According to the present invention, " A " value of determining according to following equation 3 is defined as 100 or bigger.In equation 3, [Mn], [Ti], [Zr], [La], [Ce] and [S] represent Mn, Ti, Zr, La, Ce and the S content (quality %) of welding wire respectively.If " A " value is less than 100, fire check sensitiveness increases.On the contrary, based on the gross mass of welding wire, making " A " value by adjusting Mn, Ti, Zr, La, Ce and S content is 100 or bigger, can crystallization go out MnS, thereby the raising eutectic temperature is at the final stage of solidifying prevent to emanate out at the crystal boundary place low melt liquid phase and compound.In addition, can form and contain high fusion sulfide at least a among Ti, Zr, La and the Ce.Therefore, can reduce fire check sensitiveness significantly.Stipulate the coefficient of following equation 3 according to the result of crazing-resistance test, the trend that these coefficients may be formed the sulfide of each element significantly influences.

Equation 3

$A=\frac{\left[\mathrm{Mn}\right]+20\&times;\left[\mathrm{Ti}\right]+25\&times;\left[\mathrm{Zr}\right]+50\&times;\left[\mathrm{La}\right]+50\&times;\left[\mathrm{Ce}\right]}{\left[S\right]}$

Except phosphorus (P), the unavoidable impurities that solid core welding wire of the present invention contains comprises for example Cu, Al, Ni, Cr, Mo and B.

The explained later regulation is as the reason of the composition of the welding wire that is used for gas shielded arc welding of alternative plan of the present invention.

Carbon content: 0.02～0.15 quality %

Carbon (C) is the needed element of intensity of guaranteeing weld metal, and is effective as deoxidant element.If carbon content is less than 0.02 quality %, the intensity of weld metal is insufficient.On the contrary, if carbon content surpasses 0.15 quality %, the toughness of weld metal reduces, and fire check sensitiveness increases.But adding excessive carbon can damage the drop release property and produce a large amount of sputters.This causes the welding processing damaged and a large amount of welding slags.Therefore, carbon content is set at 0.02～0.15 quality % here.

Silicone content: 0.50～1.50 quality %

Silicon (Si) also is the conforming element that promotes deoxidation to heavens, improves hardness of steel and improvement bead.If silicone content is less than 0.50 quality %, these advantages are inadequate, and bead has poor uniformity, have the toe shape of damage, usually cause stress to be concentrated and the fatigue strength reduction.Silicone content is preferably 0.60% or bigger.On the contrary, if silicone content surpasses 1.50 quality %, the fusion weldpool has too high viscosity (flow resistance), and this usually causes bulge bead (humping bead) in high-speed welding.But excessive silicon damages the drop release property and produces a large amount of sputters.This causes the welding processing of difference and a large amount of welding slags.Silicone content is 1.20 quality % or lower more preferably.

Manganese content: 1.00～3.00 quality %

Manganese (Mn) is useful and play the element of mechanical performance effect of improvement weld metal as deoxidant element as silicon.As the result of MnS crystallization, it also plays the raising eutectic temperature, thereby reduces the effect of fire check sensitiveness.If manganese content is less than 1.00 quality %, fire check sensitiveness increases, and weld metal has inadequate intensity.On the contrary, if manganese content surpasses 3.00 quality %, the fusion weldpool has too high viscosity (flow resistance), usually causes bulge bead and a large amount of welding slags in high-speed welding.Therefore, manganese content is set in 1.00～3.00 quality %.More preferably in the scope of 1.00～2.00 quality %.

Phosphorus content: 0.025 quality % or lower

Phosphorus (P) is the element that increases fire check sensitiveness.Even can not form high fusion phosphorus compound because add alloy element, so preferably phosphorus content is minimized.But the phosphorus of 0.025 quality % content is inappreciable.

Sulfur content: 0.020～0.150 quality %

The effect of sulphur (S) landing low melt metallic surface tension force, when adding suitable amount, the fatigue strength that works to improve the bead and the uniformity between the underlying metal of welding toe place and improve welding point.But under the situation that does not add following specific element, a large amount of sulphur can make in crystal grain and the sulfide chap that forms at the crystal boundary place, thereby reduces the intensity and the toughness of weld metal.Add 0.020 quality % or more the sulphur of high-load can obtain above-mentioned advantage.On the contrary, if sulfur content surpasses 0.150 quality %, even regulate the content of other element, also fire check will take place, intensity and toughness reduce significantly.Therefore, sulfur content is set at 0.020～0.150 quality %.More preferably be set in 0.040～0.150 quality %, further preferably set at 0.050～0.150 quality %.

Content of niobium: 0.005～0.50 quality %

Niobium (Nb) has affinity to sulphur, forms sulfide easily.The niobium of appropriate level works to prevent that the FeS that produces fire check from forming.In addition, thereby hardenability makes the thinner element of crystal grain because niobium is improvement, so its landing low-heat crack sensitivity and the effect of guaranteeing suitable intensity and toughness.But if content of niobium can not obtain these advantages less than 0.005 quality %, and fire check sensitiveness increases.Content of niobium is 0.02 quality % or more more preferably.On the contrary, if content of niobium surpasses 0.50 quality %, these advantages also no longer increase, and emanate at the crystal boundary place with in the dendrite array during curing, and fire check sensitiveness is increased.Excessive niobium increases the production cost of solid core welding wire, increases the viscosity (flow resistance) of fusion weldpool, produces the bulge bead, increases sputter in high-speed welding.

" be selected from the group of forming by the nickel (Ni) of the chromium (Cr) of the aluminium (Al) of the vanadium (V) of 0.005～0.5 quality %, 0.010～0.5 quality %, 0.005～0.5 quality % and 0.005～0.5 quality % at least a "

Vanadium (V), aluminium (Al), chromium (Cr) and nickel (Ni) are to increase hardenability and rise to make the crystal grain that welds the weld metal that forms thinner, guarantee suitable intensity and toughness and the element that reduces the effect of fire check sensitiveness.In order to show these advantages, each content of V, Cr and Ni is necessary for 0.005 quality % or higher, and Al content is necessary for 0.010 quality % or higher.More preferably, each content of V, Cr and Ni is necessary for 0.02 quality % or higher, and Al content is necessary for 0.030 quality % or higher.On the contrary, these elements surpass the production cost of the content increase solid core welding wire of 0.5 quality % separately, increase the viscosity (flow resistance) of fusion weldpool, and this produces the bulge bead in high-speed welding and the sputter amount increases.

Boron content: 0.001～0.010 quality %

Boron (B) is to increase hardenability and work to make the element that the crystal grain that welds the weld metal that forms is thinner, guarantee suitable intensity and toughness and reduction fire check sensitiveness.In order to show these advantages, boron content is necessary for 0.001 quality %.On the contrary, because if boron content surpasses 0.010 quality %, fire check sensitiveness increases, so the upper limit of boron content is set at 0.010 quality % or lower.Therefore, boron content is set at 0.001～0.010 quality %.

Welding method of the present invention

The solid core welding wire of first and second schemes is used to have the steel-sheet gas shielded arc welding of 0.6～10mm thickness according to the present invention.Preferred welding method and welding condition are as follows.The gas-shielded arc welding method here can be any welding method, for example CO ₂Welding, metal active gas (MAG) welding, Metallic Inert Gas (MIG) welding and Wolfram Inert Gas (TIG) welding.Can be typically according to the thickness of processor type, workpiece and shape set welding condition such as power output or electric current and speed of welding for example.MAG pulse welding, MIG pulse welding or TIG pulse welding are more effective.According to the part of welding, the purpose welding point can be the joint of any appropriate, for example banjo fixing butt jointing (butt joint) or lap joint (lap joint).The present invention goes for any joint.

Pulse machine

In the steel-sheet welding, preferably use pulse machine to be fuming here to guarantee high-speed welding and arc stability and reduction.Impulsive condition can be but be not limited to the peak current of 350～600A, the base current of 30～100A that a peak (end that the beginning of rising from pulse descends to pulse through constant peak) is 0.8～5.0 millisecond.Can weld under these conditions in the present invention.

0.6 the sheet metal that～10mm is thick

If steel-sheet thickness is less than 0.6mm, because arc force penetrates sheet metal and scorification, so be difficult to carry out the reversed polarity arc welding of rule.On the contrary, if thickness surpasses 10mm, because because thermal expansion and thermal contraction and restraining force increases, thereby too big stress is applied on the weld metal and the fusion weldpool more promptly cool off, so the danger of fire check increase.In addition, the fusion weldpool that forms in the welding of using welding wire of the present invention has low viscosity (flow resistance), and when carrying out T shape horizontal fillet welding in big leg length single track, last leg is sagging.Therefore, the sheet metal thickness of welding is preferably 0.6～10mm.With the steel-sheet intensitometer of welding, the present invention can be applied to the sheet metal of wide region, from the zero carbon steel of rule to the high strength sheet metal.Do not limit the steel-sheet intensity upper limit especially.

Test case 1

With reference to several embodiment, the outer Comparative Examples of the contrast scope of the invention is explained advantage of the present invention in more detail.The test case 1 relevant with the solid core welding wire of the present invention's first scheme at first described.

In test case 1, use the solid core welding wire of composition to carry out gas shielded arc welding with following table 1.Estimate bead formation property of high-speed welding, mechanical performance, toe diameter ρ, fire check sensitiveness and the welding processing of weld metal.The surplus of the composition of the solid core welding wire in the table 1 is iron and unavoidable impurities.

Table 1

Table 2

The method of assess performance is described below.

The mechanicalness of weld metal

Determine the mechanicalness of weld metal according to the impact test method that is used for welding point of tensile test method of stipulating among the Z of Japanese Industrial Standards (JIS) 3121 that is used for butt welded joint and JIS Z 3121 regulations.In these tests, has 560N/mm ²Or higher tensile strength and in but Bei Shi impact test, have 100 J under-20 ℃ the probe temperature or higher endergonic sample is evaluated as " well ", have less than 560N/mm ²Tensile strength or be evaluated as " defective " at the endergonic sample that in but Bei Shi impact test, has under-20 ℃ the probe temperature less than 100 J.

The bead of high-speed welding formation property

The bead of following evaluation high-speed welding formation property.The lap joint sample of high-strength steel sheet with the composition of table 2 and 2.3mm thickness with the welding current of 200～300 A and 1.3～1.5m/ minute speed of welding, uses the Ar of 80 volume % and the CO of 20 volume % on the toe opening of 1.0mm ₂Gaseous mixture make protection gas, carry out MAG pulse welding.Do not show undercutting, bulge bead, burn and penetrate and can be evaluated as " well " at the sample of lap gap in whole welding, the sample of defectives such as having for example undercutting, bulge bead, burn or penetrate is evaluated as " defective ".

Welding processing

Use high-speed camera to observe arc stability and the systematicness of droplet transfer, determine the quantity of discrete sputter, estimate welding processing.In this program, use the Ar of 80 volume % and the CO of 20 volume % ₂Gaseous mixture make protection gas, under the welding current of 200～300A, carry out no pulse MAG welding.The sample that stable electric arc is provided, has the droplet transfer of high rule and produces a small amount of sputter is evaluated as " well ", and at least one is that the sample that differs from is evaluated as " defective " in arc stability, droplet transfer systematicness and the sputter quantity.

The fire check sensitiveness of weld metal

Fire check sensitiveness with the evaluation of result weld metal of fishbone cracking test and crater crack test.The method of carrying out fishbone cracking test is at first described.Fig. 2 A is the sectional view of the position of expression sampling and testing sheet, and Fig. 2 B is a plane of representing how to prepare the test pieces of fishbone cracking test.With reference to Fig. 2 A, the thickness of the two-layer 20mm of having and comprise SM490A mild steel and make the high-strength steel sheet 11 of underlying metal and use the liner metal 13 that comprises SM490A mild steel docks welding with 45 ° oblique angles.The welding point that obtains is mechanically cut into the thickness of 5mm, thereby obtain being used for the test pieces 14 of fishbone cracking test, it has the width of 175mm, the length of 250mm and the thickness of 5mm.

Shown in Fig. 2 B, form slit 15 at regular intervals at the two ends on the long limit of test pieces 14.Slit 15 has the length of variation, is increased to another side from minor face, and the thermal deformation (thermal stress) that is applied on the motlten metal changes continuously with the length of otch.Particularly, at the minor face that slit 15 has little length, thermal deformation is big, and at another minor face that slit 15 has big length, thermal deformation is little.Test pieces 14 is placed on the copper coin 16 of thickness of the length of width with 750mm, 500mm and 25mm, carries out the TIG welding under the condition of following table 3, wherein the test board box moves.In this program, the plate end that has shorter length at otch applies static arc about 5 seconds, thus fusion plate end and make the thermal deformation of plate end, the curing crackle (fire check) of contractions/curing deformation generation when the plate end induces cooling procedure fully.Then, on welding direction 17, weld to the other end that otch has length from the plate end that crackle takes place.How far begin to prolong (how long) according to crackle from the plate end of test pieces 14 and estimate heat-resisting crackle.The length correspondence of crackle thermal deformation, the instant heating crack sensitivity.Particularly, after welding, carry out colour of solution, be determined in the bead 12 crack length that forms, determine the ratio (crackle than) of crack length and test pieces length.Crackle than be 5% or littler sample be evaluated as " well ", crackle is evaluated as " defective " than the sample that surpasses 5%.

Table 3

Welding method	Bead on the TIG plate (bead-on-plate)
		Protective gas	100%Ar, 20 liters/minute
Welding current	200A
		Speed of welding	30cm/ minute

In the crater crack test of using SM490A low-carbon (LC) metal, use 80 volume %Ar and 20 volume %CO ₂Gaseous mixture make protection gas, under the welding current of 200～300A, on the v-depression at the dark 5mm and the 90 ° of oblique angles that tilt, form long three of about 70mm intermittently with no pulse MAG welding under the same conditions and weld beads.Determine the lip-deep crackle total length of each weld bond.Determine the length of crack length and weld bond or the ratio of diameter, the mean value of the ratio of three weld bonds of use is as index.Average crack ratio be 15% or littler sample be evaluated as " well ", average crack ratio surpasses 15% sample and is evaluated as " defective ".

Toe diameter ρ

For convenience's sake, as the assessment of indices toe diameter ρ of the fatigue strength of welding point, because along with toe diameter ρ increases, stress is concentrated and is slowed down, and fatigue strength improves.Particularly, use 80 volume %Ar and 20 volume %CO ₂Gaseous mixture make protection gas, under the speed of welding of the average welding current of 200～300A and 1.3～1.5m/ minute, according to taking the pin welding automatically, the overlap joint with high-strength steel sheet of the composition of table 2 and 2.9mm thickness carries out MAG pulse welding.Measure toe diameter ρ shown in Figure 1 then.Toe diameter ρ is that 0.3mm or bigger sample are evaluated as " well ", and toe diameter ρ is evaluated as " defective " less than the sample of 0.3mm.The result of above-mentioned evaluation is illustrated in the following table 4.

Table 4

Table 4 shows that the solid core welding wire according to embodiments of the invention 1～20 all has excellent result in all evaluations.On the contrary, it is poor forming in mechanical performance, toe diameter ρ, fire check sensitiveness and the welding processing of property, weld metal at least one at the solid core welding wire of the Comparative Examples outside the scope of the invention 21～40 at the bead of high-speed welding.Particularly, because the solid core welding wire of Comparative Examples 21 has the carbon content less than prescribed limit of the present invention, so it shows inadequate weld metal intensity.Because the carbon content of the solid core welding wire of Comparative Examples 22 surpasses the scope of the present invention's regulation, so it shows the toughness of inadequate weld metal.In addition, because this solid core welding wire has " A " value less than prescribed limit of the present invention, it has the fire check sensitiveness of increase.

Because the solid core welding wire of Comparative Examples 23 has the silicone content less than prescribed limit of the present invention, so weld metal shows inadequate intensity.This solid core welding wire also shows the bead of going on business and forms property and have little toe diameter ρ in high-speed welding.On the contrary, the solid core welding wire of Comparative Examples 24 has the silicone content above prescribed limit of the present invention, thereby shows the toughness of inadequate weld metal, thick drop and the sputter of increase.The solid core welding wire of Comparative Examples 25 has less than the manganese content of prescribed limit of the present invention with less than " A " value of prescribed limit of the present invention, thereby shows the intensity of inadequate weld metal and the fire check sensitiveness of increase.On the contrary, the solid core welding wire of Comparative Examples 26 has the manganese content above prescribed limit of the present invention, thereby shows the toughness of inadequate weld metal.

The solid core welding wire of Comparative Examples 27 has the phosphorus content above prescribed limit of the present invention, thereby shows the fire check sensitiveness of increase.Although the solid core welding wire of Comparative Examples 28 has low fire check sensitiveness, it has the sulfur content less than prescribed limit of the present invention, thereby shows the bead formation property and the little toe diameter ρ of the difference in the high-speed welding.On the contrary, though the content of other element in the solid core welding wire of Comparative Examples 29 in prescribed limit of the present invention, but it has above the sulfur content of prescribed limit of the present invention with less than " A " value of prescribed limit of the present invention, thereby show high fire check sensitiveness.Comparative Examples 30,32,34 and each solid core welding wire of 35 all have " A " value less than prescribed limit of the present invention, thereby show high fire check sensitiveness.

The solid core welding wire of Comparative Examples 31 has the Ti content above prescribed limit of the present invention, thereby shows the welding slag of the sputter and the increase of thick drop, increase.Equally, the solid core welding wire of Comparative Examples 33 has the zirconium content above prescribed limit of the present invention, thereby shows the welding slag of the sputter and the increase of thick drop, increase.Comparative Examples 36,37 and 38 solid core welding wire do not contain any one among Ti, Zr, La and the Ce, and each all has " A " value less than prescribed limit of the present invention, thereby shows high fire check sensitiveness.Comparative Examples 39 and 40 solid core welding wire do not contain Ti, Zr, La and Ce, have the sulfur content above prescribed limit of the present invention, thereby show high fire check sensitiveness.

Test example 2

The test example 2 that explained later alternative plan of the present invention is relevant.In this test example, use to have the welding wire welding sheet metal of forming shown in the following table 5.Estimate bead formation property of high-speed welding, mechanical performance, toe diameter ρ, coating, fire check sensitiveness and the welding processing of weld metal.The surplus of the solid core welding wire of table 5 is iron and unavoidable impurities.

Table 5

Table 6

C	Si	Mn	P	S	Surplus
						0.04	0.02	1.35	0.013	0.003	Iron and unavoidable impurities

The method of assess performance is then described.

The mechanical performance of weld metal

Determine the mechanical performance of weld metal according to the impact test method that is used for welding point of tensile test method of stipulating among the JIS Z of Japanese Industrial Standards 3121 that is used for butt welded joint and JIS Z 3128 regulations.In these tests, has 560N/mm ²Or higher tensile strength and in the Charpy impact test, have 100 J under-20 ℃ the probe temperature or higher endergonic sample is evaluated as " well ", have less than 560N/mm ²Tensile strength or be evaluated as " defective " at the endergonic sample that in the Charpy impact test, has less than 100 J under-20 ℃ the probe temperature.

The bead of high-speed welding formation property

The bead of following evaluation high-speed welding formation property.The sample lap joint of high-strength steel sheet with the composition of table 6 and 2.9mm thickness uses 80 volume %Ar and 20 volume %CO under the speed of welding the welding current of 250A and 1.5m/ minute on the toe opening of 1.0mm ₂Gaseous mixture make protection gas, carry out MAG pulse welding.Do not show such as undercutting (undercut), bulge bead, burn and defective such as penetrate and can be evaluated as " well " by the sample of lap gap in whole welding, the sample with defective is evaluated as " defective ".

Welding processing

Use high-speed camera to observe arc stability and the systematicness of droplet transfer (droplet transfer), determine the quantity of discrete sputter, estimate welding processing.In this program, use 80 volume %Ar and 20 volume %CO ₂Gaseous mixture make protection gas, under the speed of welding of the welding current of 250A and 1.0m/ minute, carry out the MAG welding of no pulse.The sample that stable electric arc is provided, has high droplet transfer systematicness and produces a small amount of sputter is evaluated as " well ", and the sample of at least one difference is evaluated as " defective " in arc stability, droplet transfer systematicness and the sputter quantity.

Coating

In the electro-deposition application step after welding, estimate coating according to the danger of peeling off the coating layering that causes because of welding slag.Determine this danger based on the welding slag area that the welding back forms on the bead surface.In this program, use 80 volume %Ar and 20 volume %CO ₂Gaseous mixture make protection gas, under the speed of welding of the welding current of 250A and 1.0m/ minute, carry out the MAG welding of no pulse.The ratio of welding slag area and bead surface area is evaluated as " well " less than 10% sample, this ratio be 10% or bigger sample be evaluated as " defective ".

Fishbone cracking test

Fire check sensitiveness with the evaluation of result weld metal of fishbone cracking test and the test of the crater crack mentioned later.

The position of test pieces sampling is shown in Fig. 2 A.With reference to Fig. 2 A, the two-layer mild steel SM490A with 20mm thickness that makes underlying metal 11 uses the liner metal 13 that comprises mild steel SM490A, docks welding with 45 ° oblique angles.The welding point that obtains is mechanically cut into the thickness of 5mm, thereby obtain being used for the test pieces 14 of fishbone cracking test, it has the width of 175mm, the length of 250mm and the thickness of 5mm.

Then, shown in Fig. 2 B, form slit 15 at regular intervals at two two ends of growing limits of test pieces 14.Slit 15 has the length of variation, increases from the minor face to the another side, so that be applied to thermal deformation (thermal stress) on the motlten metal with the length variations of slit.Particularly, at the minor face that slit 15 has little length, thermal deformation is big, and at another minor face that slit 15 has big length, thermal deformation is little.With test pieces 14 be placed on width with 750mm, 500mm length and, on the copper coin 16 of the thickness of 25mm, under the condition of following table 7, carry out the TIG welding, wherein the test board box moves.In this program, thereby apply fusion plate end and make the thermal deformation of plate end, the curing crackle (fire check) of contractions/curing deformation generation when the plate end induces cooling procedure fully in static arc about 5 seconds by the plate end that has shorter length at slit.Then, on welding direction 17, weld to the other end that slit has length from the plate end that crackle takes place.How far begin to prolong (how long) according to crackle from the plate end of test pieces 14 and estimate heat-resisting crackle.The length correspondence of crackle thermal deformation, the instant heating crack sensitivity.Particularly, after welding, carry out colour of solution, be determined at the crack length that forms in the bead 12, determine the ratio (crackle ratio) of crack length and test pieces length.Crackle than be 5% or littler sample be evaluated as " well ", crackle is evaluated as " defective " than the sample that surpasses 5%.

Table 7

Welding method	Bead on the TIG plate
		Protective gas	100%Ar, 20 liters/minute
Welding current	200A
		Speed of welding	30cm/ minute

The crater crack test

Use the SM490A sheet metal, on the v-depression at the dark 5mm and the 90 ° of oblique angles that tilt,, form three long welding beads of about 70mm intermittently under the same conditions with the MAG welding.Determine the lip-deep crackle total length of each weld bond.Determine the length of crack length and weld bond or the ratio of diameter, the mean value of this ratio of three weld bonds of use is as index.Average crack than be 15% or littler sample be evaluated as " well ", average crack is evaluated as " defective " than the sample that surpasses 15%.

Toe diameter ρ

For convenience's sake, measure the index of toe diameter ρ as the fatigue strength of welding point, because along with toe diameter ρ increases, stress is concentrated and is slowed down, and fatigue strength improves.Particularly, use 80 volume %Ar and 20 volume %CO ₂Gaseous mixture make protection gas, under the speed of welding of the welding current of 250 A and 1.5m/ minute, take the pin welding according to level, the overlap joint (lap joint) of the high-strength steel sheet of composition with table 6 and 2.9mm thickness is carried out MAG pulse welding.Measure toe diameter ρ shown in Figure 1 then.Toe diameter ρ is that 0.3mm or bigger sample are evaluated as " well ", and toe diameter ρ is evaluated as " defective " less than the sample of 0.3mm.The result of above-mentioned evaluation is illustrated in the following table 8.

Table 8

These results show that the solid core welding wire of embodiment 1～25 has the composition in the prescribed limit of the present invention, all are excellent in all evaluations.On the contrary, the solid core welding wire of Comparative Examples 26～50 has the outer composition of prescribed limit of the present invention, and it is poor forming in mechanical performance, toe diameter ρ, fire check sensitiveness, coating and the welding processing of property, weld metal at least one at the bead of high-speed welding.

Particularly, table 8 shows that the solid core welding wire of the embodiment 1～25 with the composition in the prescribed limit of the present invention all is excellent in all evaluations.On the contrary, the solid core welding wire of Comparative Examples 26～50 has the outer composition of prescribed limit of the present invention, and it is poor forming in mechanical performance, toe diameter ρ, coating, fire check sensitiveness and the welding processing of property, weld metal at least one at the bead of high-speed welding.

Though the solid core welding wire of Comparative Examples 26～30 does not contain any among Cr, Ni, Nb, V, A1 and the B or contains any their content separately in these elements less than the scope of the present invention's regulation, thereby weld metal shows fire check sensitiveness and the inadequate intensity and the toughness of increase.The solid core welding wire of Comparative Examples 31 has too high carbon content, thereby shows the toughness of inadequate weld metal and the fire check sensitiveness of increase.It also shows the sputter of thick drop, increase and produces a large amount of welding slags of the coating of difference.The solid core welding wire of Comparative Examples 32 has too high manganese content, produces the bulge bead and can not form normal bead thereby show in the toughness, high-speed welding of inadequate weld metal.It also produces a large amount of welding slags, the coating that performance is gone on business.The solid core welding wire of Comparative Examples 33 has too high silicone content, thereby shows the toughness of inadequate weld metal, thick drop and the sputter of increase.It also produces a large amount of welding slags, thus the coating that performance is gone on business.The solid core welding wire of Comparative Examples 34 has too high phosphorus content, shows high fire check sensitiveness.

Comparative Examples 35 and 36 solid core welding wire have too low sulfur content, although show low fire check sensitiveness, the bead that performance is gone on business in high-speed welding forms property and little toe diameter.At least a content in the solid core welding wire of Comparative Examples 37～40 among Cr, Ni, V and the Al is too high, from but expensive, in high-speed welding, produce the bulge bead.They also show thick drop and a large amount of sputters.The solid core welding wire of Comparative Examples 41 has too high content of niobium, thereby shows high fire check sensitiveness, is expensive, produces the bulge bead in high-speed welding.They also show thick drop and produce a large amount of sputters.The solid core welding wire of Comparative Examples 42 has too high boron content, thereby shows high fire check sensitiveness.The solid core welding wire of Comparative Examples 43 has too high boron and content of vanadium, thereby shows high fire check sensitiveness, is expensive, produces the bulge bead in high-speed welding.It also shows thick drop and a large amount of sputters.

The solid core welding wire of Comparative Examples 44 has too high silicone content and too low manganese content, thereby shows inadequate weld metal intensity, thick drop and the sputter of increase.In high-speed welding, also cause producing bulge bead and a large amount of welding slags, coating that performance is gone on business and high fire check sensitiveness.The solid core welding wire of Comparative Examples 45 has too high sulfur content, thereby weld metal shows inadequate intensity and toughness and high fire check sensitiveness.The solid core welding wire of Comparative Examples 46 has too low carbon and manganese content, thereby weld metal shows inadequate intensity and high fire check sensitiveness.The solid core welding wire of Comparative Examples 47 has too high carbon content and too low silicone content, thereby weld metal has the fire check sensitiveness of inadequate toughness and increase.It also shows the bead uniformity of going on business, little toe diameter, thick drop, the sputter of increase and a large amount of welding slags of generation, the coating that performance is gone on business.The solid core welding wire of Comparative Examples 48 has too low silicone content and too high phosphorus content, thereby weld metal shows inadequate intensity, the bead uniformity of difference, little toe diameter and high fire check sensitiveness.

The solid core welding wire of Comparative Examples 49 has too high carbon and manganese content, thereby weld metal shows the toughness of undue intensity and difference.In high-speed welding, also produce the bulge bead, thereby can not form normal bead, show the sputter of thick drop, increase, a large amount of welding slags, the coating of difference and high fire check sensitiveness.The solid core welding wire of Comparative Examples 50 has too low carbon content and too high phosphorus content, thereby shows inadequate weld metal intensity and high fire check sensitiveness.

Claims (1)

1. solid core welding wire that is used for gas shielded arc welding, described solid core welding wire comprises:

Based on the gross mass of described welding wire,

The carbon of 02～0.15 quality % (C);

The silicon of 50～1.50 quality % (Si);

1.00 the manganese of～3.00 quality % (Mn);

The sulphur of 020～0.150 quality % (S);

The niobium of 005～0.5 quality % (Nb); With

Be selected from least a in the group of forming by the boron (B) of the nickel (Ni) of the chromium (Cr) of the aluminium (Al) of the vanadium (V) of 0.005～0.5 quality %, 0.010～0.5 quality %, 0.005～0.5 quality %, 0.005～0.5 quality % and 0.0010～0.0100 quality %;

Surplus is iron and unavoidable impurities,

Wherein the content as the phosphorus (P) of unavoidable impurities is 0.025 quality % or lower.

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