MXPA97003884A - Metal connucleo welding wire for welding galvanized steels - Google Patents

Abstract

The present invention relates to a welding wire with metal center that is used for galvanized and annealed steels of low percentage of coal and alloy, in covered arc welding, the welding wire with metal center consists of: a steel cladding With a low percentage of coal, and a composition of the center surrounded by a steel coating with a low percentage of carbon, the composition of the center includes, by total weight of the welding wire with a metal center, between approximately 0.05-0.20% Ti and between approximately 0.05-1.00% Nb, the composition of the center is, by total weight of the welding wire with metal center, between approximately 0.1-12.0%, where the welding wire provides, according to the welding, percentage of up to 100 cm / min. reduced arc ionization potential and spatter, as well as improved arc stability and protection, and where the welding wire produces, according to the weld, percentage up to 100 cm / min, the weld deposits have reduced blowholes and porosity, as well as surface tension of the melt solder bath in a wetting feature improves

Description

WELDING WIRE WITH METAL NUCLEUS FOR WELDING GALVANIZED STEELS BACKGROUND OF THE INVENTION The present invention relates in general to welding wires with a metal core, and more specifically to welding wires with a metal core that can be used for electrically welding and gas protection galvanized and galvanized steels and low alloy annealing and low carbon content at relatively high welding rates to produce improved weld deposit in overlapping or overlapping work pieces without a gap between them. In many applications of electric welding with gas protection, galvanized and galvanized steels and low carbon and low alloy annealing are welded in a single pass, high welding rate operations requiring weld deposits in joints without gaps with minimal hot cracks, minimal hole formation and essentially no porosity, minimal slag formation, good wetting characteristics and corrosion resistance, no embrittlement of liquid metal, higher impact resistance and a minimum tensile stress of approximately 85,000 psi.

Galvanized steels are formed by coating or depositing zinc on steel in hot dip, or hot galvanizing or electroplating processes. The galvanized metal is sometimes annealed to form a galvanized and annealed metal with improved properties, including reduction in the disintegration of the coating, which tends to occur during metal forming formations. However, when welding galvanized and galvanized and annealed metals, there is a tendency for zinc vapor to enter the molten solder crucible, resulting in a defective weld deposit. Specifically, the vaporized zinc coating of the metal surface tends to create turbulence in the shielding gas, thereby introducing atmospheric nitrogen and oxygen into the weld, resulting in nitrogen and oxygen contamination of the weld deposit, and increased human waste. In addition, the zinc vapor is not soluble in the molten steel, and any vapor that does not escape from the molten solder deposit prior to solidification, results in the formation of holes and pores in the weld deposit. The formation of holes and pores is particularly severe when welding joints without a gap between the work pieces, since there is a limited area for the steam to escape from the molten solder deposit. Galvanized metals are known for better resistance to corrosion, and are increasingly used in the automotive industry for automotive chassis, fenders, axles, support assemblies, grills and water radiators, among other parts, which often require gaskets. welding without gaps. These metals are generally low carbon and low alloy steels with good press forming characteristics. In some applications, the industry uses annealed, low-carbon, low-annealed galvanized steels with thicknesses ranging from approximately 0.030 to 0.250 inches, and a coating weight of approximately 45 gm / m2. Steel of relatively thin thickness often must be soldered in a single pass at high welding rates to prevent the welding arc from burning the metal. Assembly line operations also require a single pass, high welding regimes to improve productivity. Sometimes welding regimes of approximately 150 cm / min are required. However, at high welding rates, the molten solder deposit tends to cool relatively quickly, thereby reducing the time for the steam to escape from the solder deposit, which increases the formation of holes and porosity in the solder deposit . The rapidly cooled weld deposit formed in high welding rate applications also tends to result in poor weld deposit contour, or humectant characteristic. The high weld rates are also a source of turbulence in the shielding gas, which tends to increase the addition of atmospheric nitrogen and oxygen in the weld deposit, as discussed above. At present, galvanized steels are welded with self-protecting welding cables containing magnesium and barium. Magnesium displaces nitrogen and oxygen to reduce porosity. But magnesium also reacts with the zinc coating to cause embrittlement of the liquid metal, which is unacceptable for many industrial applications. These self-protected wires also produce excessive smoke, which is undesirable, and also produce excessive slag, which must be removed before applying coatings on the weld deposit. Slag formation also tends to prevent steam from escaping from the molten solder deposit, resulting in more holes and porosities, which are also increased when welding together without gaps. In addition, barium is considered toxic and creates an unacceptable health risk. JP Patent Application No. 61-21432 discusses a solid welding wire for gas protected arc welding galvanized steels. However, solid wires have an undesirably deep "finger" penetration, and reduced productivity compared to metallic core wires. In addition, the solid welding wire of JP Patent Application No. 61-21432 has a relatively high carbon content, which can reduce ductility and increase slag and sensitivity to hot cracking. This solid welding wire also has a relatively high titanium content, which increases slag formation, and includes aluminum, which increases splash and provides a poor wetting characteristic. The solid welding wire of JP Patent Application No. 61-21432, therefore tends to be expensive, and is not suitable for welding at high welding rates. JP Patent Application No. 1989-3833 discusses a solid welding wire for welding steel with electric arc and gas protection at high welding rates. JP Patent Application No. 1989-3833, however, teaches that it is undesirable to add aluminum, titanium, silica and other deoxidizing agents to the solid welding wire, because the deoxidizing agents increase the activity of the zinc in the molten solder deposit. , which results in the formation of holes. The solid welding wire of JP Patent Application No. 1989-3833 also produces slag, which possibly results in the essential removal of the deoxidizing agents from the welding wire. The solid welding wire of JP Patent Application 1989-3833 includes niobium and vanadium to reduce the formation of holes and pores in cases where the effectiveness of gas protection is reduced.

But the amounts of niobium and vanadium disclosed in Patent Application No. 1989-3833 result in increased hot cracking, and have an adverse effect on ductility. In addition, this solid wire has increased strength and hardening resulting in higher loads on the dies placed on the wire during welding wire fabrication, which increases production costs. In view of the above discussion, there is a demonstrated need for advancement in the technique of metal core electrodes. It is therefore an object of the present invention to provide a new metallic core electrode that overcomes the problems of the prior art. It is also an object of the present invention to provide a new metal-core electrode usable for electrically and gas-protected welding of galvanized and annealed and low-alloy galvanized and low alloy steels at relatively high welding rates to produce improved weld deposits in unions that do not have gaps. It is another object of the present invention to provide a new metal core electrode usable for electrically and gas-protected welding of galvanized and galvanized steels and annealed low carbon and low alloy of relatively thin thickness at relatively high welding rates. It is another object of the present invention to provide a new metal-core electrode usable for electrically and gas-protected welding of galvanized and galvanized steels and low carbon and low alloy anneables at welding rates up to 150 cm / min, where the deposit of welding has a reduced formation of holes and pores, no embrittlement of liquid metal or hot cracking, improvements in the wetting characteristics of the weld deposit, greater resistance to impact and ductility, and better resistance to corrosion, at deposit rates relatively high welding It is another object of the present invention to provide a new electrode with metal core for electrically and gas-protected welding of galvanized and annealed and galvanized low-alloy and low carbon steels, where the metallic core electrode produces a reduction in the ionization of the arc, reduces slag, and improves protection at relatively high weld deposit rates. Accordingly, the invention is directed to an electrode with a metallic core that can be used to electrically and gas-weld galvanized and galvanized and annealed steels. The metal core electrode includes a low carbon steel shield surrounding a core composition. In one embodiment, the protection of low carbon steel includes, for the total weight of the metal core electrode, approximately between 0.01 - 0.03% C, and the core composition includes, depending on the total weight of the metal core electrode, between approximately 0.05 - 0.20% Ti, and between approximately 0.05 - 1.00% Nb, where the metallic core electrode includes between approximately 0.40 - 0.50% Si. In one embodiment, the core composition includes Mn insofar as the metal core electrode includes between about 0.1-1.0% Mn, and iron powder. The composition of the core may also include, for the total weight of the metal-core electrode, between approximately 0.02-1.00% Cu, and in another embodiment between approximately 0.05. - 0.80% V. The core composition is, by the total weight of the metal core electrode, between about 0.001 - 12.0%, and in an alternative mode between about 5.0 - 7.0%. The electrode provides, at welding rates of up to 150 cm / min, a reduction in arc and slag ionization potential, and better arc stability and protection. The electrode produces, at welding rates up to 150 cm / min, welding deposits that have reduction in the holes and porosity, no embrittlement of liquid metal, a greater resistance to corrosion and ductility, and a reduction in the tension of the surface of the weld deposit, resulting in a better wetting characteristic when they are welded together without a gap. These and other objects, features and advantages of the present invention will be more apparent when considering the following Detailed Description of the Invention with the accompanying drawings, which may be out of proportion for ease of understanding, where similar structures and steps are referred to by numbers and corresponding indicators. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of an overlapped joint that essentially has no gap between overlapping plates. Figure 2 is an end view of the horizontal and vertical plates arranged in a T-configuration with a gap between them. DETAILED DESCRIPTION OF THE INVENTION The invention is directed to a new welding wire with a metallic core, or tubular welding electrode, comprising a shell of low carbon steel having a tubular core filled with a nuclear composition. The nuclear composition is about 0.001 - 12.0% of the total weight of the metallic core electrode. The low carbon steel shell includes minimal amounts of carbon to minimize slag and hot cracking. In the present metallic core welding wire, it was found that a carbon content greater than 0.06% has a tendency toward hot cracking of the weld deposit, as will be discussed later. In one embodiment, the low carbon steel shell includes, for the total weight of the metal core welding wire, between about 0.01-0.10% C, and in another embodiment between about 0.01-0.03% C. In one embodiment, the Core composition includes only niobium, or in combination with vanadium to prevent the formation of holes and pores. It is expected that tantalum will also have the same beneficial effect as niobium in preventing the formation of holes or pores when welding galvanized and annealed steels. Niobium and vanadium also reduce the surface tension of the solder deposit, which results in a better wetting characteristic, of the molten solder deposit and, consequently, provide a better solder deposit contour, which allows a higher soldering rate. welding deposit. In addition, niobium and vanadium increase the hardening of the weld deposit, which is necessary to increase the resistance to the weld deposit. In one embodiment, the nuclear composition includes, according to the total weight of the metal core welding wire, between about 0.05-1.00% Nb, and in another embodiment, between about 0.30-0.40% Nb. In the present metallic core welding wire, an amount of niobium greater than 0.73% seems to increase the tendency towards hot cracking. In an alternative embodiment, the nuclear composition includes between about 0.05-0.80% V, and in another embodiment between 0.05-020% V. Increased amounts of vanadium tend to increase hot cracking and decrease the ductility of the weld deposit. The nuclear composition can also include only titanium or a combination with niobium, or vanadium, or both to prevent the formation of holes or pores. Titanium is a denitrogenating agent that combines with the nitrogen introduced into the weld deposit and reduces porosity. Titanium also tends to reduce the surface tension in the weld deposit, allowing higher weld rates as discussed above, with respect to niobium and vanadium. Additionally, titanium has a low ionization energy, so that titanium tends to stabilize the electric arc. A more stable electric arc provides a more stable protective gas envelope, which results in a reduction in the amounts of atmospheric nitrogen and oxygen that are introduced into the molten solder tank. In one embodiment, the nuclear composition includes, according to the total weight of the metal core welding wire, between about 0.05 - 0.20% Ti, and in another embodiment, between about 0.10 - 0.20% Ti. Quantities of titanium greater than 0.15% tend to increase the formation of slag in the weld deposit, which is undesirable, because the slag tends to trap steam in the molten weld deposit, resulting in increased hole formation. Slag is also undesirable, because it must ultimately be removed from the weld deposit in many applications, which increases costs. Reducing the amount of titanium to less than 0.10% increases spatter, decreases bow stability, and reduces the wetting characteristics of the weld deposit. In another embodiment, the nuclear composition includes copper to prevent the formation of holes and pores, and reduce hot cracking. The presence of copper in the weld deposit also tends to reduce the embrittlement of the liquid metal by aligning with the zinc to minimize the segregation of zinc at the grain boundaries of the weld deposit. In addition, the copper in the metal core electrode results in the formation of a protective barrier on the surface of the weld deposit, which improves the corrosion resistance. In one embodiment, the nuclear composition includes, depending on the total weight of the metal core electrode, it results in the formation of a protective barrier on the surface of the weld deposit, which improves the corrosion resistance. In one embodiment, the nuclear composition includes, depending on the total weight of the metal core electrode, between about 0.02-1.00% Cu, and in another embodiment between about 0.40-0.60% Cu. Copper reduction tends to increase hot cracking and reduce corrosion resistance. The metal core welding wire of the present invention includes minimal amounts of silica and manganese, which are primarily deoxidizing agents to reduce the formation of holes, minimize hot cracking, and improve the wetting property of the weld deposit. The welding wire with metal core includes in the shell, or nuclear composition, or both, by total weight of the metal core welding wire, between approximately 0.1-1.0% Si, and in alternative mode between approximately 0.4-0.5% Si. The metal core weld also includes in the shell, or nuclear composition, or both, by the total weight of the metal core welding wire, between about 0.1-1.0% Mn, and in an alternative embodiment between 0.6 and 0.8% Mn. The nuclear composition can also include iron powder as a filler. In one embodiment, the metal core welding wire includes, by total weight of metal core welding wire, less than 0.50% nickel, less than 0.50% chromium, less than 0.50% molybdenum, and less than 0.50% of tungsten. The nuclear composition which is, by the total weight of the metallic core welding wire, between about 0.001-12.0%, and in an alternative embodiment between about 5.0 and 7.0%. The lower limit of the core composition is determined by the percentage of the total weight of the constituents of the core composition. Generally, the formation of holes tends to increase as the percentage of the core composition increases. The oxygen content of the solder deposit is significantly reduced by reducing the oxygen content of the solder wire, which results, among other advantages, in a higher resistance to the impact of the solder deposit. The oxygen content of the welding wire is reduced by using a low oxygen iron powder in the composition of the core, or by reducing the amount of iron powder filler material in the core composition, or by firing the wire in an inert atmosphere, as disclosed in copending United States Patent Application No., filed in, titled "Metal Core Welding Wire with Reduced Core Filling Percentage", assigned to the assignee of the present invention, and incorporated herein by reference. The compositions of the present invention are applicable to wires of metal core of any diameter, and in particular to wire diameters of between about 0.157 cm (0.030 - 0.062 inches). EXAMPLES Table I illustrates the metallic core wire compositions according to various exemplary embodiments of the present invention, and data relating to hole formation, hot cracking, ductility based on a U-bend Test, and a Weldability, as will be discussed later. An entry "-" in Table I indicates that no data was obtained for that particular test.

TABLE I PROOF 2. HOLES CRACKING IN CAUENTE BENDING IN U -60F CORE % CAUTION APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED APPROVED NO APPROVED NO APPROVED The Hole data in Table I was determined after visual inspection after making an overlapping joint weld of approximately 8.9 cm (3.5 inches) in length over overlapping galvanized and annealed steel plates with a thickness of 1.7 mm. The overlap was maintained at a minimum of 0.64 cm (0.25 inch) weld regimes. The steel plates were welded without any gap between them, placing weights on the upper steel plate. Figure 1 illustrates an overlapping plate layout without gap. The welding operation was carried out under the following conditions: 230 - 240 amperes; 24.4 volts; 0.045 wire with 1.90 cm (0.75 inch) electrode protrusion (ESO); minimum travel speed of 100 cm / min; gas protection of 92% Ar / 8% C02 flowing at 40-45 ft3 per hour; push angle of 20-27 degrees. The Hot Cracking data in Table I was determined by measuring hot cracks, after welding on both sides of a vertical plate initially welded with dots to a horizontal plate in a T-shaped configuration.

Figure 2 illustrates the horizontal and vertical plates, which were initially separated by a gap of at least about 0.20 cm (0.09 inches). The plates had a thickness of about 0.60 cm (0.25 inches), about 5.1 cm (2.00 inches) wide, and about 25.4 cm (10.0 inches) long. The surfaces of the plates were sanded, and the composition of the plate included approximately: C 0.04% Mn 0.24% Si 0.001%, and Al 0.07%. The welding operation was carried out under the following conditions: 220 - 240 amperes; 24 volts; 0.045 wire with ESO of 1.27 - 1.90 cm (0.25 - 0.75 inches); minimum travel speed of 40 cm / min; and gas protection 92% Ar / 8% C02 flowing at 40-45 ft3 per hour. The above Hot Cracking tests are considered a severe welding test. A crack of less than about 1.27 cm (0.5 inch) generally does not pose a problem in most applications where these metallic core welding wires are used. None of the exemplary metallic welding wire compositions of Table I is expected to result in hot cracking when used to weld overlapped galvanized steel and low carbon annealed joint. The unit of measurement for the Hot Cracking data in Table I is inches. The U-bend data in Table I were determined after visual inspection, after welding on two overlapping galvanized and annealed plates 1.7 mm thick, 5.1 cm (2 inches) wide, and 20.32 cm (8 inches) ) long without having gaps between them. The welded plates were then cut longitudinally to obtain a strip 5.1 cm (2 inches) wide with the weld disposed approximately in the center of the strip. The welded strip was then bent into a U in a radius of about 2.54 cm (1 inch) at a temperature of -60 degrees F. The bending was formed over the length of the weld, which was on the outer circumference of the bent strip. Cracks greater than approximately 0.159 cm (0.062 inches) are indicated in units of inches. The Weldability data in Table I were obtained by rating the following three categories: 1.) "Splash", 2.) "Welding Tank Wetting", and 3.) "Arc Stability" on a scale of 0 to 6, and adding the qualifications for each metallic core welding wire composition The lower rating is 0, and the highest is 6.

While the above written description of the invention allows anyone who knows the technique to make and use what is currently considered the best embodiment of the invention, those skilled in the art will appreciate and understand the existence of variations, combinations , modifications and equivalents within the spirit and scope of the specific exemplary modalities that are disclosed herein. Accordingly, the present invention will be limited not by the specific exemplary embodiments disclosed herein, but by all embodiments within the scope of the appended claims.

Claims (5)

1 . A metal-core welding wire that can be used for electro-welding and arc welding of galvanized and galvanized and low-carbon annealed steels, where the metal-core welding wire comprises: a low-carbon steel shell; and a core composition surrounded by the low carbon steel shell, where the core composition includes, according to the total weight of the metal core welding wire, between about 0.05 - 0.20% Ti, and between about 0.05 - 1.00% Nb , where the core composition is, by the total weight of the metal core welding wire, between about 2.5 - 12.0%; and a trace amount of Ni, where the welding wire provides, at weld rates of up to 100 cm / min, a reduction in splash and ionization potential of the arc, and greater protection and arc stability, and where the welding wire produces, at welding rates of up to 100 cm / min, weld deposits with a reduction in the formation of holes and porosity, and a reduction in the surface tension of the weld deposit, resulting in a better characteristic of humidification.

2. The metal core welding wire of claim 1, wherein the core composition includes, according to the total weight of the metal core core welding wire, between about 0.02-1.00% Cu.

3 . The metallic core welding wire of claim 1, further comprising between about 0.1-1.0% Si, and between about 0.1-1.0% Mn, wherein the low carbon steel shell includes, according to the total weight of the wire metal core welding, between about 0.01 - 0.03% C.

4. The metallic core welding wire of claim 1, wherein the nuclear composition includes, by the total weight of the metallic core welding wire, between about 0.05 - 0.80% V.

5. The metallic core welding wire of claim 1, further comprising between about 0.1-1.0% Si, and between about 0.1-1.0% Mn, where the low carbon steel shell includes, depending on the total weight of the metallic core welding wire, between approximately 0.01 - 0.03% C, and the composition of the core includes, according to the total weight of the metallic core welding wire, between 0.30-0.40% Nb, between about 0.10-0.20 Ti, and Fe powder, wherein the core composition is, according to the total weight of the metal core welding wire between about 5.0 -7.0%. 6 The metal core welding wire of claim 16, wherein the core composition includes, according to the total weight of the metal core welding wire, between about 0.40-0.60% Cu. SUMMARY A metal core welding wire that can be used to electrically weld and gas-protected, gap-free joints in galvanized and galvanized steels and low carbon and low alloy anneals. The metal core welding wire includes a low carbon steel shell surrounding a core composition. In one embodiment, the low carbon steel shell includes, depending on the total weight of the metal core welding wire, between about 0.01-0.03% C, and the core composition includes, based on the total weight of the core welding wire. metallic, between approximately 0.05 - 0.20% Ti, between approximately 0.05 -1.00% Nb, Fe powder, and Mn to the extent that the metal core welding wire includes between approximately 0.1 - 1.0% Mn, where the welding wire of metallic core includes between approximately 0.1 - 1.0% Si. The composition of the core is, according to the total weight of the metal core welding wire, between about 0.001 - 12.0%. The metal core welding wire provides, at welding rates of up to 150 cm / min, a reduction in splash and arc ionization potential, and increased arc stability and protection. The metallic core welding wire produces, at weld rates up to 150 cm / min, weld deposits with a reduction in the formation of porosity and holes, no embrittlement of liquid metal, and a reduction in the surface tension of the deposit of welding, which results in a better wetting characteristic.