JP2015186817A - Gas shield arc welding wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas shield arc welding wire excellent in wire feedability and capable of acquiring a weld metal having a little diffusible hydrogen quantity.SOLUTION: A gas shield arc welding wire is characterized by containing 0.002 to 0.30 g of polytetrafluoroethylene in powder type at the room temperature, and 0.2 to 1.3 g of one or two kinds or more of chlorofluorocarbon, perfluoropolyether and fluoroester in liquid at the room temperature per 10 kg of the wire on the wire surface.

Description

  The present invention relates to a gas shielded arc welding wire, and more particularly to a gas shielded arc welding wire that can provide a weld metal having good wire feedability and a small amount of diffusible hydrogen.

  The gas shielded arc welding wire includes a solid wire and a flux-cored wire, and can be welded in all positions to obtain a highly reliable welded joint. Therefore, it is widely used in the manufacture of sheet steel structures for transportation equipment such as large structures mainly composed of shipbuilding, construction and bridges, and automobiles.

  Arc welding work using gas shielded arc welding wire is continuously welded from the conduit tube formed in a spiral inside the conduit cable and the tip of the welding torch connected to it by the feed roller of the wire feeder. It is used by the method of arc melting in the atmosphere of shielding gas while feeding the wire.

  In addition, the conduit cable is made of a long and soft material of 6 m or longer in order to facilitate the welding work, and is adjusted up and down or left and right to adjust the distance from the wire supply device to the welded part and to weld the narrow part. It is often used after being bent into a loop or wound in a loop to adjust its length. When used in such a situation, the welding wire increases the surface resistance in the spiral conduit tube and the contact friction part, increases the feeding resistance and increases the feeding resistance, and smoothly feeds the welding wire. It becomes difficult.

In addition, when a defect occurs in the welded joint, it has a great adverse effect on the welded structure, so it is important to prevent the welded joint from being defective. As a defect generated in the weld joint, there is a cold crack of the weld metal, and the main cause of the cold crack is diffusible hydrogen that has entered the weld metal. Sources of diffusible hydrogen include hydrogen groups in welding wire steel, hydrogen groups in the flux of welding flux-cored wires, and hydrogen groups in lubricating oil applied to smoothly feed the welding wire. is there. Therefore, it is particularly desirable to reduce the lubricating oil of the welding wire. However, if the amount of lubricating oil applied is small, the wire feedability may be poor and defects other than cold cracking such as poor fusion may occur. is there.

  Accordingly, there is a need for a welding wire that provides a weld metal that has good wire feedability and a small amount of diffusible hydrogen. Therefore, for example, in Japanese Patent Application Laid-Open No. 5-23731 (Patent Document 1), dry drawing is performed with a solid lubricant containing an appropriate amount of polytetrafluoroethylene, molybdenum disulfide, graphite, mica, sericite, and talc. A flux-cored wire having an appropriate amount of the lubricant is disclosed. The flux-cored wire described in Patent Document 1 is excellent in wire feedability, but has a mineral containing a hydrogen group in the lubricant, so that the amount of diffusible hydrogen in the weld metal is increased, particularly in high-tensile steel. When welding is performed, cold cracking may occur.

  Japanese Patent Laid-Open No. 6-277877 (Patent Document 2) discloses a wire in which 1 to 500 ppm of perfluoropolyether is applied to the wire surface. When welding is performed using the welding wire described in Patent Document 2, if the bending at the time of welding is small, the wire feedability is excellent and the arc is stable, but if the bending at the time of powder welding is large, the welding is performed. The surface of the welding wire is scraped into the conduit tube due to friction between the wire and the conduit tube, increasing the feeding resistance of the welding wire, making the wire feedability worse, making the arc unstable, and defects such as poor fusion. Is likely to occur.

  Furthermore, Japanese Patent Laid-Open No. 2001-150186 (Patent Document 3) discloses a flux-cored wire in which an organic compound is attached to the flux of a welding flux-cored wire to reduce diffusible hydrogen. Since the flux-cored wire for welding described in Patent Document 3 contains an organic compound in the flux, the amount of diffusible hydrogen in the weld metal is high, and particularly when high-tensile steel is welded, cold cracking may occur. is there. There is also a problem that the wire feedability is inferior.

JP-A-5-23731 JP-A-6-277877 JP 2001-150186 A

  An object of this invention is to provide the wire for gas shielded arc welding from which the weld metal with favorable wire feeding property and few diffusible hydrogen amounts is obtained.

  The gist of the present invention is that, in a gas shielded arc welding wire, 0.002 to 0.30 g of powdered polytetrafluoroethylene per 10 kg of wire on the wire surface, chlorofluorocarbon, perfluoro It exists in the wire for gas shielded arc welding characterized by having 0.2-1.3g of 1 type, or 2 or more types of a polyether and fluoroester.

  According to the gas shielded arc welding wire of the present invention, even when welding for a long time using a soft and long conduit cable, a weld metal having a good wire feeding property and a small amount of diffusible hydrogen is used. It is possible to provide a high-quality welded joint that can be obtained and has no weld defects.

It is a figure which shows the apparatus of the wire feeding property test in the Example of this invention.

In order to solve the above-mentioned problems, the present inventors have made various studies on a feed lubricant applied to the wire surface of a wire for gas shielded arc welding. As a result, by applying an appropriate amount of one or more kinds of polytetrafluoroethylene powdered at room temperature and chlorofluorocarbon, perfluoropolyether and fluoroester that are liquid at room temperature to the wire surface, It has been found that a weld metal having good wire feedability and a small amount of diffusible hydrogen can be obtained even when welding is performed for a long time using a soft and long conduit cable.

The lubricant applied to the wire surface is 0.002 to 0.30 g of powdered polytetrafluoroethylene at room temperature per 10 kg of wire, chlorofluorocarbon, perfluoropolyether and fluoro, which are liquid at room temperature. One type or two or more types of ester is 0.2 to 1.3 g (hereinafter referred to as g / 10 kgW).

  Polytetrafluoroethylene powdered at normal temperature suppresses the feeding resistance of the welding wire in the conduit tube and improves the wire feeding property. When polytetrafluoroethylene is less than 0.002 g / 10 kgW, the feeding resistance of the welding wire in the conduit tube increases, the wire feeding performance is poor, and the arc becomes unstable. On the other hand, when polytetrafluoroethylene exceeds 0.30 g / 10 kgW, the wire slips with the feeding roller, the arc becomes unstable, and the amount of spatter generated increases. Therefore, the polytetrafluoroethylene powdered at room temperature is 0.002 to 0.30 g / 10 kgW.

  A small amount of powdered polytetrafluoroethylene at room temperature accumulates in the conduit tube when it is welded for a long time by contact with the conduit tube, but this accumulated polytetrafluoroethylene is sent to the welding wire. It works to reduce the feeding resistance. Moreover, it is preferable that the particle diameter of polytetrafluoroethylene is 10 μm or less because the feeding resistance of the welding wire is reduced and the wire feeding property is improved.

One or more of chlorofluorocarbons, perfluoropolyethers, and fluoroesters that are liquid at room temperature form a film on the wire surface to improve wire feedability, and Tetrafluoroethylene is adhered to further improve the wire feedability. Further, since chlorofluorocarbon, perfluoropolyether and fluoroester do not contain hydrogen groups, the amount of diffusible hydrogen in the weld metal is not increased. If one or more of chlorofluorocarbon, perfluoropolyether and fluoroester, which are liquid at room temperature on the wire surface, is less than 0.2 g / 10 kgW, the welding wire is fed in the conduit tube. The feed resistance is large, the wire feedability is poor, and the arc is somewhat unstable.

On the other hand, if one or more of chlorofluorocarbon, perfluoropolyether and fluoroester on the surface of the wire exceeds 1.3 g / 10 kgW, the wire slips with the feed roller and the chlorofluorocarbon Bons, perfluoropolyethers and fluoroesters have high insulation resistance, poor electrical conductivity at the welding tip, and arc becomes unstable. Accordingly, one or more of chlorofluorocarbon, perfluoropolyether and fluoroester which are liquid at room temperature on the wire surface is 0.2 to 1.3 g / 10 kgW. In addition, the viscosity of chlorofluorocarbon, perfluoropolyether and fluoroester is preferably 10 to ²⁰⁰ mm ² / S at 40 ° C. in order to facilitate application to the surface of the welding wire.

The method for producing a wire for gas shielded arc welding according to the present invention comprises finishing and drawing a flux-cored wire or a solid wire to the product diameter, and adding powdered polytetrafluoroethylene at room temperature to a liquid at room temperature. Lubricants dispersed in one or more of certain chlorofluorocarbons, perfluoropolyethers and fluoroesters are applied to the wire surface to form spooled or pail-packed wires.

In addition, the flux-cored wire for gas shielded arc welding is made of a steel that has no seam in the steel outer shell obtained by welding the seam of the steel outer shell and a steel that is not welded in the seam of the steel outer shell Although it can be roughly classified into a wire having a seam in the outer skin, any cross-sectional shape wire can be used in the present invention.

Hereinafter, the effect of the present invention will be described in detail with reference to examples.
Gas shielded arc welding wire with a wire diameter of 1.2 mm shown in Table 1 (JIS Z3313 T591T1-1CA-N2M1-U, flux-cored wire for gas shielded arc welding that is seamless on a steel outer shell with a flux filling rate of 13%, and JIS Z3312 G59JA1UC3M1T (solid wire for gas shielded arc welding), one or two kinds of powdered polytetrafluoroethylene at room temperature and chlorofluorocarbon, perfluoropolyether and fluoroester liquid at room temperature The above-described coating amount was changed in various ways to make a spool winding wire. The powdery polytetrafluoroethylene having an average particle diameter of 3 μm was used. The viscosity of chlorofluorocarbon, perfluoropolyether and fluoroester was 20-60 mm ² / S at 40 ° C.

表１に示すワイヤＮｏ．１〜７は本発明例であり、Ｎｏ．８〜１２は比較例である。

Wire No. shown in Table 1 Nos. 1 to 7 are examples of the present invention. 8 to 12 are comparative examples.

  The wire feedability, arc stability, and diffusible hydrogen content of the weld metal were investigated for each prototype wire. The wire feedability was 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 welding tip 6 through a conduit tube included in the conduit cable 4. . Then, bead-on-plate welding is performed between the welding tip 6 and the steel plate 7. The conduit cable 4 was 6 m long and provided with a bend 8 formed with two 75 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 ratio 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. Welding is performed using a new conduit tube for each prototype wire under the welding conditions shown in Table 2 for 120 minutes, measuring the slip rate SL and the feeding resistance R for 20 minutes from the start of welding to the end of welding for 100 minutes, and calculating the average value. Asked. 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. The amount of diffusible hydrogen in the weld metal was measured according to the method for measuring the amount of hydrogen in the steel weld zone of JIS Z3118. The amount of diffusible hydrogen in the weld metal was considered good when it was 2.4 mL / 100 g or less. The results are summarized in Table 3.

表３に示すワイヤＮｏ．１〜７が本発明例、ワイヤＮｏ．８〜１２は比較例である。

Wire No. shown in Table 3 1-7 are examples of the present invention, wire Nos. 8 to 12 are comparative examples.

  In the present invention, the wire No. 1 to 7 are adhesions of one or more of polytetrafluoroethylene, which is a powdery lubricant at room temperature, and lubricants, chlorofluorocarbon, perfluoropolyether and fluoroester, which are liquid at room temperature. Since the amount was appropriate, the slip rate SL and the feed resistance R were low, the wire feedability was good, the arc was stable, the amount of diffusible hydrogen in the weld metal was small, and the results were extremely satisfactory.

  In the comparative example, the wire No. In No. 8, since the adhesion amount of the powdery lubricant polytetrafluoroethylene was small at room temperature, the feeding resistance R was high and the arc was somewhat unstable. Wire No. No. 9 had a large amount of powdered polytetrafluoroethylene adhering at room temperature, causing slippage in the feed roller, increasing the slip ratio SL, making the arc unstable, and increasing the amount of spatter generated. .

  Wire No. In No. 10, since the total adhesion amount of chlorofluorocarbon and fluoroester, which are liquid lubricants at room temperature, is small, the feeding resistance R is large, the wire feeding property is deteriorated, and the arc is somewhat unstable. Wire No. No. 11 has a large amount of adhesion of chlorofluorocarbon, perfluoropolyether and fluoroester, which are liquid lubricants at room temperature, and therefore has a high slip ratio SL, poor electrical conductivity at the welding tip, and arcing. It became unstable. Wire No. No. 12 used a synthetic ester containing a hydrogen group, so that the amount of diffusible hydrogen in the weld metal increased.

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


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

Claims (1)

In a gas shielded arc welding wire, 0.002 to 0.30 g of powdered polytetrafluoroethylene at room temperature per 10 kg of wire on the wire surface, chlorofluorocarbon, perfluoropolyether and liquid at room temperature A gas shielded arc welding wire having 0.2 to 1.3 g of one or more of fluoroesters.

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