JP2006175452A - COPPER-PLATED SOLID WIRE FOR Ar-CO2 MIXED GAS SHIELDED ARC WELDING - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper-plated solid wire for Ar-CO<SB>2</SB>mixed gas shielded arc welding having excellent welding workability such as less spatter generation and excellent wire feedability, less wear of a tip and excellent arc stability even when performing the welding for a long time, in particular, from a low-current range to a transition range. <P>SOLUTION: In the copper-plated solid wire for Ar-CO<SB>2</SB>mixed gas shielded arc welding, the wire has a composition consisting of, by mass, 0.02-0.10% C, 0.40-0.95% Si, 1.0-1.95% Mn, and 0.03-0.15% Ti, and the balance Fe with inevitable impurities, and contains lubricant of 0.5-2.5 g in total consisting of lubricating oil containing 0.005-0.50 g molybdenum disulfide and 0.008-0.15 g phosphatide per 10 kg of the wire, and the balance lubricating oil which is liquid at normal temperature on the surface of the wire. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a copper-plated solid wire for Ar—CO ₂ mixed gas shielded arc welding, and in particular, even when welding for a long time with a welding current from a low current region to a transition region, the spatter generation amount is small and the wire feedability is good. Further, the present invention relates to a copper-plated solid wire for Ar—CO ₂ mixed gas shielded arc welding, which has excellent welding workability, such as less wear of contact tips (hereinafter referred to as tips) and good arc stability.

The gas shielded arc welding method enables all-position welding and provides a highly reliable welded joint. Therefore, it is widely used in the manufacture of steel structures for transportation equipment such as large structures mainly composed of buildings, bridges, and chemical machinery and automobiles. The shielding gas, due in many cases to use the CO ₂ gas from the economy and defect tolerance, the use of CO ₂ gas amount of occurrence of spatter many cleaning welding point around the surface of the steel sheet (chisel or grinder Sputter removal work) and cleaning work of the shield nozzle at the tip of the welding torch (spatter removal) are required.

Therefore, in particular, in the case of welding using a robot, a mixed gas in which 5 to 25% by volume of CO ₂ gas is mixed with Ar is often used in order to suppress the generation of spatter. When this mixed gas is used, the droplet transfer form is sprayed in a high current region, and the amount of spatter generated is extremely small. However, in the low current region, the amount of spatter generated increases as in the case of welding using CO ₂ gas. Also, a relatively large amount of spatter is generated in the welding current in the transition region that is intermediate between the high current region and the low current region.

Therefore, as a technique for suppressing the amount of occurrence of a patch in a low current region, for example, Ar − using a pulse power source in Japanese Patent Application Laid-Open No. 9-99390 (Patent Document 1) and Japanese Patent Application Laid-Open No. 10-305389 (Patent Document 2). There is a proposal of a wire for CO ₂ mixed gas shielded arc welding.
However, with these technologies, the amount of spatter generated in the welding current from the low current region to the transition region is reduced. However, the pulse power source used is very expensive, and the amount of spatter generated by welding with a general welding power source is small. Wire is needed.

As a technique for suppressing the amount of spatter generated using an Ar—CO ₂ mixed gas, for example, Japanese Patent Application Laid-Open No. 8-132280 (Patent Document 3) and Japanese Patent Application Laid-Open No. 2000-246485 (Patent Document 4) describe a trace amount of Ca. There is a proposal of a welding wire containing K.
However, both of these technologies are intended to reduce spatter when welding is performed in a high current range, that is, when the droplet transition state is in the form of a spray. is not.

Also, when using a robot, welding work is performed by continuously feeding the wire from the conduit tube formed in a spiral shape inside the conduit cable and the tip of the welding torch connected by the feed roller of the wire feeder. However, it is used in a method of arc melting in an atmosphere of Ar—CO ₂ gas. In this case, the conduit cable is long and soft in order to facilitate the movement of the welding torch, and is adjusted up and down or in order to adjust the distance from the wire feeder to the welded part and to weld the narrow part. It is often used by bending left and right or winding it in a loop. When used in such a situation, the above-described welding wire increases the surface of the spiral conduit tube and the contact friction portion, increases the feeding resistance, and makes it difficult to feed the wire smoothly.

  On the other hand, recently, various studies have been made on wires in which the copper surface is not plated with copper. For example, in Japanese Patent Laid-Open No. 9-263679 (Patent Document 5) and Japanese Patent Laid-Open No. 2004-1061 (Patent Document 6). Discloses a welding wire in which the amount of spatter generated is reduced without copper plating. However, in these techniques, if the welding is carried out for a long time, the tip wear becomes severe and the arc becomes unstable, so it is necessary to frequently replace the tip.

JP-A-9-99390 JP-A-10-305389 JP-A-8-132280 JP 2000-246485 A JP-A-9-263679 JP 2004-1061 A

The present invention relates to a copper-plated solid wire for Ar—CO ₂ mixed gas shielded arc welding, and in particular, even when welding for a long time with a welding current from a low current region to a transition region, the spatter generation amount is small and the wire feedability is good. Furthermore, an object of the present invention is to provide a copper-plated solid wire for Ar—CO ₂ mixed gas shielded arc welding having excellent welding workability, such as less wear of the tip and good arc stability.

The gist of the present invention is that, in a copper-plated solid wire for Ar—CO ₂ mixed gas shielded arc welding, as a wire component, by mass%, C: 0.02 to 0.10%, Si: 0.40 to 0.95 %, Mn: 1.0 to 1.95%, Ti: 0.03 to 0.15%, the balance being Fe and inevitable impurities, and molybdenum disulfide per 10 kg of wire on the wire surface in an amount of 0.1%. 005 to 0.50 g, 0.008 to 0.15 g of phospholipid, and the balance is characterized by having a total of 0.5 to 2.5 g of a lubricant composed of lubricating oil that is liquid at room temperature.

Further, the arithmetic average roughness Ra of the surface roughness measured in the direction of 30 ° with respect to the longitudinal direction of the wire surface is 0.04 to 0.12 μm.
Further, the present invention is the copper-plated solid wire for Ar—CO ₂ mixed gas shielded arc welding characterized in that the wire surface lubricant contains 0.004 to 0.25 g of K per 10 kg of wire.

According to the copper-plated solid wire for Ar—CO ₂ mixed gas shielded arc welding of the present invention, even when welding with a welding current from a low current region to a transition region for a long time, the spatter generation amount is small and the wire feedability is low. This makes it possible to perform welding with excellent welding workability, such as good wear resistance and low arc wear.

In order to solve the above-mentioned problems, the present inventors have used a welding current from a low current region to a transition region (for example, a wire diameter of 1.2 mm, a shielding gas of about 150 to 280 A in the case of Ar-20% CO ₂ ), and a wire Various investigations were made on the components, the feed lubricant applied to the wire surface, and the wire surface condition. As a result, by limiting the content of C, Si, Mn and Ti in the wire component, the stability of the arc and the occurrence of spatter are suppressed, and by containing an appropriate amount of K in the lubricant, the droplets become fine particles. The arc is extremely stable.

  In addition, by applying appropriate amount of molybdenum disulfide, phospholipid and lubricating oil that is liquid at room temperature to the wire surface and limiting the wire surface roughness, transition from low current range using a soft and long conduit cable It has been found that even when welding is performed for a long time with the welding current in the region, the amount of spatter is small, the wire feedability is good, the tip wear is extremely small, and a stable arc can be obtained.

C in the wire component is added to suppress the amount of spatter generated. When C is less than 0.02 mass% (hereinafter referred to as “%”), the amount of spatter generated increases. On the other hand, when C exceeds 0.10%, a large amount of spatter is generated.
Si is added to stabilize the arc. When Si is less than 0.40%, the arc becomes unstable. If it exceeds 0.95%, the amount of spatter generated increases.

Mn is also added to stabilize the arc as with Si. If Mn is less than 1.0%, the arc becomes unstable. If it exceeds 1.95%, the amount of spatter generated increases.
Ti suppresses the generation of spatter by reducing the size of the droplets, particularly with a welding current in a low current range. If Ti is less than 0.03%, the effect is not obtained, and large spatters occur frequently. On the other hand, if Ti exceeds 0.15%, the amount of spatter generated increases.
A small amount of Ni, Mo, Cr, Al, Zr, V and Nb can be added to adjust the strength of the weld metal.

Lubricant applied to the surface of the wire is a total of lubricants made of lubricating oil containing 0.005 to 0.50 g of molybdenum disulfide and 0.008 to 0.15 g of phospholipid per 10 kg of wire, and the balance being liquid at room temperature. 0.5 to 2.5 g (hereinafter referred to as g / 10 kgW).
Molybdenum disulfide suppresses the feeding resistance in the conduit tube to improve the wire feeding property, and reduces the friction resistance between the tip inner wall and the wire surface to reduce the wear of the tip. If the molybdenum disulfide is less than 0.005 g / 10 kgW, the feeding resistance is increased in the conduit tube, the wire feeding performance becomes poor, the wear amount of the tip is increased, and the arc becomes unstable. Conversely, if molybdenum disulfide exceeds 0.50 g / 10 kgW, the arc becomes unstable and the amount of spatter generated increases. In addition, it is preferable that the particle diameter of molybdenum disulfide is 1.0 μm or less because the feeding resistance is reduced and the wire feeding property is improved.

  The phospholipid has an action of uniformly dispersing molybdenum disulfide on the surface of the wire by coexisting with a lubricating oil that is liquid at room temperature to be described later. When the phospholipid is less than 0.008 g / 10 kgW, molybdenum disulfide on the surface of the wire does not adhere uniformly, and there is a portion where the feeding resistance increases in the conduit tube, resulting in poor wire feeding performance and chip. As the amount of wear increases, the arc becomes unstable. Conversely, if the phospholipid exceeds 0.15 g / 10 kgW, the amount of spatter generated increases.

  The phospholipid referred to in the present invention means a substance mainly composed of a phospholipid such as lecithin (phosphatidylcon), phosphatidylethanolamine, phosphazinynicitol, and, for example, phospholipid obtained from soybean, egg yolk, and the like. There are powdery products containing about 95% of acid lipids, pastes containing about 65% of phospholipids and about 35% of vegetable oils such as soybean oil, and any of these can be used. The resulting lecithin is preferred.

  Lubricating oil, which is liquid at room temperature in the lubricant, has a coating on the wire surface, complements the lubricating action of molybdenum disulfide during wire feeding, and improves wire feeding properties. The lubricating oil may be animal or vegetable oil, mineral oil or synthetic oil. Palm oil, rapeseed oil, castor oil, pig oil, cow oil, fish oil, etc. can be used as animal and vegetable oils, and machine oil, turbine oil, spindle oil, etc. can be used as mineral oils. As the synthetic oil, hydrocarbon type, ester type, polyglycol type, polyphenol type, silicone type and fluorocarbon type can be used. In order to further improve the lubrication performance, lubricating agents such as various fatty acids and phosphorus, halogen, and sulfur extreme pressure additives may be added to the lubricating oil, and the oxidation of the lubricating oil is prevented. Additives (antioxidants) may be added.

  The lubricant contained on the wire surface is 0.5 to 2.5 g / 10 kgW in total of the molybdenum disulfide, lecithin, and lubricating oil that is liquid at room temperature. If the total amount of the lubricant is less than 0.5 g / 10 kgW, the feeding resistance increases in the conduit tube, the wire feeding performance becomes poor, and the amount of wear of the tip increases and the arc becomes unstable. . On the other hand, if it exceeds 2.5 g / 10 kgW, the wire slips at the feeding roller portion, and the arc becomes unstable.

  Copper plating on the wire surface reduces the frictional resistance in the conduit tube and improves the electrical conductivity at the tip of the tip to stabilize the arc. Furthermore, even when welding for a long time, the tip wear is extremely small and a stable arc can be maintained. However, when the calculated average roughness Ra of the surface roughness measured in the direction of 30 ° with respect to the longitudinal direction of the wire surface defined in JIS B0601-1994 exceeds 0.12 μm, the feeding resistance is caused by friction in the conduit tube. It becomes larger, the wire feedability becomes worse, and the arc becomes unstable.

  Further, if welding is performed for a long time due to the frictional resistance between the inner wall of the tip and the wire surface, the amount of wear of the tip increases and the arc becomes unstable. Copper plating improves the electrical conductivity, lubricity and wear resistance of the chip, and also has the effect of improving rust prevention. The plating thickness is preferably about 0.3 to 1.2 μm. Further, if the calculated average roughness Ra of the surface roughness measured in the direction of 30 ° with respect to the longitudinal direction of the wire surface is less than 0.04 μm, the wire slips at the feeding roller portion of the wire feeding device and the arc is generated. It becomes unstable.

Further, when K is included in the wire surface lubricant by 0.004 to 0.25 g / 10 kgW, the droplets become fine and the arc is extremely stable. If the K of the wire surface lubricant is less than 0.004 g / 10 kgW, the effect cannot be exhibited, and if it exceeds 0.25 g / 10 kgW, the amount of spatter generated increases.
The copper-plated solid wire for carbon dioxide shielded arc welding of the present invention controls the diameter reduction rate by applying copper plating to the wire surface of the wire element wire that has been temporarily drawn and then reducing the diameter by wet hole die drawing. Then, the target wire surface roughness is set, and the drawn lubricant is applied to the wire surface after finishing drawing or after finishing drawing.

Hereinafter, the effect of the present invention will be specifically described with reference to examples.
A spool-wound wire was manufactured by changing the components of the welding wire having a wire diameter of 1.2 mm shown in Table 1, the wire surface condition, and the amount of lubricant applied.

  For each prototype wire, wire feedability, tip wear, arc condition and spatter generation were investigated. The wire feedability, tip wear amount, and arc state were evaluated using the apparatus shown in FIG. In FIG. 1, the spool winding wire 2 set in the feeder 1 is pulled out by the feeding roller 3 and fed from the torch 5 at the tip thereof to the chip 6 through the conduit tube included in the conduit cable 4. Then, bead-on-plate welding is performed between the tip 6 and the steel plate 7. The conduit cable 4 was 6 m long and provided with a bend 8 formed with two 150 mm diameter loops to give a feeding resistance. The feeder 1 is provided with a detector (not shown) for the peripheral speed Vr (set wire speed) of the feed roller and an actual wire speed Vw detector 9.

  The slip rate SL of the wire feedability evaluation index is represented by SL = (Vr−Vw) / Vr × 100. Further, the reaction force that the wire receives from the conduit tube during wire feeding by the load cell 10 provided in the feeding roller portion was detected as the feeding resistance R. For welding, use a new conduit tube for each prototype wire and check the condition No. shown in Table 2. The welding was performed for 45 minutes under the welding conditions of 1 and the average value was obtained by measuring the slip rate SL and the feeding resistance R for 30 minutes from the start of welding to the end of welding for 15 minutes. When the slip rate SL was 10% or less and the feed resistance R was 6 kgf or less, it was determined that the wire feedability was good. Further, the wear amount of the tip was measured by using a new tip (inner diameter: 1.4 mm) for each prototype wire and measuring the inner diameter of the portion with the greatest wear after welding. The chip wear amount was evaluated as good when the wear amount was 0.05 mm or less.

  The amount of spatter generated was determined under the condition No. 1 shown in Table 2 by bead-on-plate welding using a copper collection box without replacing the conduit tube and tip after the wire feedability test and tip wear test were completed. And the spatter collected by welding five times under the welding conditions of No. 2 (one welding time of 1.5 min) was converted into the amount of generation per minute. The amount of spatter generated is 0.5 g / min or less, and the arc is stable and the workability is good. The results are summarized in Table 3.

  In Tables 1 and 3, wires No. 1 to 9 are examples of the present invention, and wires No. 10 to 18 are comparative examples. Test Nos. 1 to 9, which are examples of the present invention, have an appropriate wire component range, molybdenum disulfide that is a lubricant on the wire surface, phospholipid, adhesion amount of K, and the total amount of lubricant including lubricant and wire. Arithmetic average roughness Ra measured in the direction of 30 ° with respect to the longitudinal direction of the surface is appropriate, so the slip rate SL and feed resistance R are low, the wire feedability is good, the tip wear amount and the transition from the low current range The amount of spatter generated by the welding current in the region was small, the arc was stable, and the welding workability was good.

In the comparative example, the wire No. 10 had a large amount of spatter due to the low C of the wire component. Moreover, since Si was low, the arc was unstable. Further, since the calculated average roughness Ra of the surface roughness measured in the direction of 30 ° with respect to the longitudinal direction of the wire surface is low, the slip ratio SL is high and the wire feedability is also poor.
Since wire No. 11 has a high C of the wire component, large-scale sputtering occurred. Moreover, since Mn was low, the arc was unstable.

The wire No. 12 had a large amount of spatter due to the high Si of the wire component. In addition, since the calculated average roughness Ra of the surface roughness measured in the direction of 30 ° with respect to the longitudinal direction of the wire surface is high, the feeding resistance R is large, the wire feeding performance is poor, and the wear amount of the tip is increased, resulting in an arc. Became unstable.
The wire No. 13 had a large amount of spatter due to the high Mn of the wire component. Moreover, since K in the wire surface lubricant was small, the arc was somewhat unstable.

Wire No. 14 had a large amount of spatter due to its high Ti wire component. Further, since the wire surface lubricant molybdenum disulfide is small, the feeding resistance R is large, the wire feeding performance is poor, the wear amount of the tip is increased, and the arc becomes unstable.
The wire No. 15 had a large amount of spatter generated due to the low Ti of the wire component. Further, since the wire surface lubricant has a small amount of phospholipid (lecithin), the feeding resistance R is large, the wire feeding performance is poor, the wear amount of the tip is increased, and the arc becomes unstable.

Wire No. 16 had a large amount of molybdenum surface disulfide, molybdenum disulfide, so that the arc was unstable and the amount of spatter was increased. Further, since the total amount of the wire surface lubricant is small, the feeding resistance R is large, the wire feeding property is poor, the tip wear amount is increased, and the arc becomes unstable.
In wire No. 17, the amount of spatter generated increased because of the large amount of phospholipid (lecithin) as the wire surface lubricant. Further, since the copper surface was not plated with copper, the feed resistance R was large, the wire feedability was poor, the tip wear amount was increased, and the arc became unstable.
Since the total amount of the wire surface lubricant was large, the wire No. 18 had a high slip rate SL and poor wire feedability. Moreover, since there was much K in a wire surface lubricant, there was much spatter generation amount.

It is drawing which shows the apparatus of the wire feeding test in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Feeder 2 Spool winding wire 3 Feed roller 4 Conduit cable 5 Torch 6 Tip 7 Steel plate 8 Bending part of conduit cable 9 Wire actual speed detector 10 Load cell


Patent Applicant Nippon Steel & Sumikin Welding Industry Co., Ltd.
Attorney Attorney Shiina and others 1

Claims (3)

In the copper-plated solid wire for Ar—CO ₂ mixed gas shielded arc welding, the wire component is 0.02 to 0.10% by mass, Si: 0.40 to 0.95%, Mn: 1.0 to 1.95%, Ti: 0.03 to 0.15%, consisting of the balance Fe and inevitable impurities, and 0.005 to 0.50 g of molybdenum disulfide per 10 kg of wire on the wire surface, phospholipid 0.008 to 0.15 g, and the balance has a total of 0.5 to 2.5 g of a lubricant composed of a lubricating oil that is liquid at room temperature. Ar-CO ₂ mixed gas shielded copper-plated solid for arc welding Wire. _2. The Ar—CO ₂ mixed gas shielded arc according to claim 1, wherein the arithmetic average roughness Ra of the surface roughness measured in the direction of 30 ° with respect to the longitudinal direction of the wire surface is 0.04 to 0.12 μm. Copper plated solid wire for welding. According to claim 1 or 2 Ar-CO ₂ mixed gas shielded arc welding copper plating solid wire according to, characterized in that 0.004~0.25g containing wire 10kg per K on the wire surface lubricants.

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