JP2017113762A - Laser welded shape steel made of stainless steel excellent in corrosion resistance and glare-proofness, and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser welded shape steel made of a stainless steel not having a temper color on the surface, and excellent in glare-proofness, concerning a laser welded shape steel having a corner joint part.SOLUTION: A laser welded shape steel made of a stainless steel, which is a welded shape steel in which an angular laser welded joint part is formed with a web member and a flange material, and which is excellent in glare-proofness is manufactured by adjusting 60-degree glossiness of a surface to be 75 or lower by immersing the welded shape steel after being welded into acid solution, by using a laser weld method for irradiating a laser beam as a weld method when welding the web member and the flange material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a welded shape steel in which a square weld joint is formed by laser welding using stainless steel as a raw material and a laser beam as a heat source.

In recent years, as a method of manufacturing a section steel such as a C-shaped steel used for a beam or the like constituting a building frame, a laser beam is applied to a corner joint formed by two members, a flange member and a web member. Laser welding methods are being studied.
For example, as can be seen in Patent Document 1, a groove having a certain angle is provided between the flange material and the web material, and the laser beam is irradiated at an angle parallel to the abutting surface.
In this method, the penetrating laser beam does not damage the surface of the member, but it is efficient because heating forms an oxide film on the surface of the flange material and web material around the weld and it is necessary to remove it. Cannot be manufactured.

In addition, among these welded steels, stainless steel with extremely high corrosion resistance is used as a bridge, road material, and building member in the beach area as seen in Patent Document 2 so that it is maintenance-free. Are considered.
In Patent Document 2, laser welding is applied for the purpose of suppressing deformation that occurs when welding stainless steel and requiring little correction.
However, when laser welding is performed on stainless steel in the atmosphere, an oxide film called a temper color is generated on the surface of the plate material corresponding to the vicinity of the weld or the back surface of the weld.

Japanese Utility Model Laid-Open No. 5-18783 Japanese Patent Laid-Open No. 11-123575

Since this temper color is a chromium oxide, the amount of chromium in the stainless steel is reduced, so that the corrosion resistance is lowered and the appearance is also deteriorated. Therefore, it is necessary to remove the temper color after welding.
When the temper collar near the weld is removed with a brush or the like, polishing eyes are generated. However, the polishing area and the non-polishing area have a non-uniform appearance, and a multi-pass polishing process is required to achieve a uniform appearance. , Productivity is very low.

  Also, when the welded steel is used as a member exposed to the exterior of the building, if the surface is very small, such as a mirror-polished surface, the reflection of sunlight will be severe, and the surface will have antiglare properties. Laser welded sections made of steel are desired.

  The present invention has been devised to solve such problems, and a laser comprising a stainless steel as a raw material and having a corner joint portion or a T-shaped joint portion, and both a corner joint portion and a T-shaped joint portion. An object of the present invention is to provide a laser welded shape steel that is anti-glare and has excellent corrosion resistance and appearance by suppressing the temper color on the surface of the flange material generated during welding.

In order to achieve the object, the laser welded shape steel of the present invention includes a corner joint portion or a T-shaped joint portion using a stainless steel plate and a flange material and a web material, and further includes both a corner joint portion and a T-shaped joint portion. The laser welded shape steel is characterized in that the 60 ° glossiness of the surface is 75 or less.
Moreover, as stainless steel, a component is C: 0.025 mass% or less, Si: 0.60 mass% or less, Mn: 1.00 mass% or less, P: 0.040 mass% or less, S: 0.020 mass %, Ni: 0.60 mass% or less, Cr: 16.00-35.00 mass%, Mo: 0.30-6.00 mass%, N: 0.025 mass% or less, ferritic stainless steel It is also a feature.
Furthermore, one or two of Nb: 0.10 to 1.00% by mass, Ti: 0.05 to 0.30% by mass, and Al: 0.01 to 0.50% by mass are added to the stainless steel. Ferritic stainless steel including the above can also be used.

  As a method of manufacturing the above-mentioned stainless steel laser welded shape steel, a flange member and a web material made of stainless steel plate are used as a corner joint part or a T-shaped joint part, and further, both a corner joint part and a T-shaped joint part are used. When the provided welded steel is manufactured, it is characterized by being immersed in an acidic solution after being welded using a laser welding method of irradiating a laser beam as a welding method.

The stainless steel laser welded shape steel according to the present invention has excellent corrosion resistance and antiglare properties because it suppresses the temper color and surface gloss generated at the time of welding on the flange material surface which is the back surface of the welded portion. Further, when ferritic stainless steel is used for the web material and the flange material, it is possible to realize a laser-welded steel made of stainless steel with reduced costs.
Further, the surface of the laser welded steel made of stainless steel can be realized by performing the step of immersing in acidic welding for a certain period of time once, so that it can be produced very efficiently as compared with multi-pass polishing.

The figure explaining the method of laser welding the welded shape steel including a corner joint part by one-pass irradiation from one side The figure explaining the method of carrying out laser welding of the welded shape steel containing a corner joint part and a T-shaped joint part by one-pass irradiation from one side Stainless steel laser welded section including corner joints Stainless steel laser welded section including square joint and T-shaped joint

  As shown in FIG. 1, a laser welded steel 1 made of stainless steel according to the present invention has a laser beam by one pass from one side of a corner joint formed by vertically pressing the end of a web material 3 against a flange material 2. 4 is produced by welding with irradiation. At this time, the irradiation angle θ of the laser beam 4 to the flange material 2 is set to 30 degrees or less. The reason for irradiating the laser beam at an inclination is to increase the penetration into the flange material 2 in order to ensure a certain bonding strength when the thickness of the flange material 2 is thicker than the thickness of the web material 3. .

In the laser shaped steel made of stainless steel manufactured by such a method, the present inventors have found that the temper collar is formed in the vicinity of the welded portion or in the region corresponding to the rear surface of the welded portion of the surface of the flange material depending on the surface temperature of the flange material. Although it occurs, it has been found that the temper color can be removed by dipping the manufactured stainless steel laser welded shape steel in an acidic solution, and it can also have antiglare properties.
When laser welding is performed using SUS304 having a plate thickness of 2.3 mm as a raw material by the method shown in FIG. 1, as shown in FIG. 3, in the manufactured laser welded steel 21 made of stainless steel, in the vicinity of the welded portion 24. The temper color is generated on the end face of the flange 22 and the region 25 corresponding to the back surface of the welded portion. After welding, the time for immersing the stainless steel laser welded shape steel in an acidic solution containing 8% by mass of hydrofluoric acid and 8% by mass of nitric acid was changed, and the flange material of the laser welded shape steel made of stainless steel 2 and the 60 degree glossiness of the surface of the web material 3 were compared with the antiglare level visually confirmed when exposed to sunlight outdoors. Moreover, the removal state of the temper color was also confirmed.

  As a result of confirming the experimental results, the surface condition satisfying the antiglare property was obtained during the immersion time in which the temper color was removed, and the 60 degree glossiness at that time was 75 or less. Therefore, as an index that can achieve both the antiglare property and the removal of the temper color, the 60 degree glossiness is set to 75 or less.

The material of the stainless steel laser welded shape steel of the present invention is not particularly limited as long as it is stainless steel, and austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, and the like can be used.
Of these, when ferritic stainless steel is used, the cost can be made relatively low, and the corrosion resistance can be maintained depending on the components. For this reason, it is possible to realize a laser welded section made of stainless steel with good quality and low cost.

In particular, when it is necessary to secure product cost and corrosion resistance, ferritic stainless steel including the following component ranges can be used.
C: 0.025% by mass or less C is an element useful for obtaining the strength of steel, but when it is contained in a large amount, it tends to lower the corrosion resistance. The C content is preferably 0.025% by mass or less.
Si: 0.60% by mass or less Si is an element useful as a deoxidizer and a heat source in the steel making process, but when it is contained in a large amount, it tends to harden the steel. The content of Si is preferably 0.60% by mass or less.
Mn: 1.00% by mass or less Mn is an element useful as a deoxidizing agent in the steel making process, but when included in a large amount, Mn tends to form an austenite phase. The Mn content is preferably 1.00% by mass or less.
P: 0.040% by mass or less P tends to lower the corrosion resistance. The P content is preferably 0.040% by mass or less.
S: 0.020% by mass or less S tends to lower the corrosion resistance. The content of S is preferably 0.020% by mass or less.
Ni: 0.60% by mass or less Ni is preferable in terms of the effect of suppressing the progress of corrosion and the effect of improving the toughness of ferritic stainless steel. The Ni content is preferably 0.60% by mass or less.
Cr: 16.00-35.00 mass%
Cr is an element useful for ensuring corrosion resistance. However, when it is contained in a large amount, Cr tends to decrease not only in high cost but also in workability. The content of Cr is preferably 16.00 to 35.00% by mass.
Mo: 0.30 to 6.00 mass%
Mo is an element useful for improving the corrosion resistance of stainless steel in the presence of Cr, but if it is contained in a large amount, it tends to reduce not only the cost but also the workability. The content of Mo is preferably 0.30 to 6.00 mass%.
N: 0.025% by mass or less N, when contained in a large amount like C, tends to lower the corrosion resistance. The N content is preferably 0.025% by mass or less.

The stainless steel laser welded shape steel of the present invention further includes Nb: 0.10 to 1.00% by mass, Ti: 0.05 to 0.30% by mass, Al: 0.01 to 0.50% by mass. Among them, ferritic stainless steel containing one or more types can be used for further improving the corrosion resistance.
Nb: 0.10 to 1.00% by mass
Nb has a strong affinity with C and N and is preferable in terms of suppressing the intergranular corrosion of ferritic stainless steel, but a large amount of Nb tends to inhibit toughness. The content of Nb is preferably 0.10 to 1.00% by mass.
Ti: 0.05 to 0.30 mass%
Ti is preferable because it has a strong affinity with C and N and suppresses intergranular corrosion of ferritic stainless steel, but a large amount of Ti tends to deteriorate the surface quality of the steel. As for content of Ti, 0.05-0.30 mass% is more preferable.
Al: 0.01 to 0.50 mass%
Al is an effective element for refining and casting as a deoxidizer, but if it is added excessively, it degrades the surface quality and lowers the weldability and low temperature toughness of steel. As for Al content, 0.01-0.50 mass% is more preferable.

The 60 degree glossiness on the surfaces of the web material and the flange material was measured as follows in accordance with JIS Z 8741-1997.
The glossiness is measured using a portable glossiness meter GMX-102 (Murakami Color Research Laboratory Co., Ltd.), and the measurement position of the glossiness is the position near the bead for the web material and the back surface of the welded portion for the flange material. And measured at three arbitrary locations apart in the length direction of the welded steel.

Example 1
It is an austenitic stainless steel plate (SUS304) with a plate thickness of 2.3 mm, 3.2 mm, and 4.5 mm, and the flange material is 100 mm wide × 5 m long, and the web material is 100 mm wide × 5 m long. A welded shape steel was manufactured by welding under the laser welding conditions shown in Table 1 by the method shown in FIG. The irradiation angle θ of the laser beam was 20 °. Subsequently, the welded stainless steel laser welded shape steel was immersed in an acidic solution containing 8% by mass of hydrofluoric acid and 8% by mass of nitric acid with the immersion time changed. For the laser welded steel immersed, observation of the removal state of the temper color and 60 degree glossiness of the surfaces of the flange material 2 and the web material 3 were measured. The gloss values shown in the following Tables 2 to 4 are the highest values among the measured values of the glossiness measured for the stainless steel laser welded shape steel manufactured under each condition.
The results of Example 1 are shown in Table 2.

As shown in Table 2, in the surface state without the temper color, the 60 ° gloss was 75 or less, and in that state, the antiglare property was also secured.
(Example 2)

  As the flange member 2 and the web member 3, a ferritic stainless steel plate containing Cr: 30%, Mo: 2%, Ti: 0.15%, Nb: 0.15%, Al: 0.09%, and the balance Fe is used. The other conditions were the same as in Example 1 including the step of welding by laser and the step of immersing in an acidic solution, and a laser-welded section was produced.

  Table 3 shows the results of measurement of the temper color state and 60 degree glossiness. In the surface state without the temper color, the 60 ° gloss was 75 or less, and in that state, the antiglare property was also secured.

(Example 3)
Using the material of Example 2 as the flange member 2 and the web member 3, a welded steel 1 having a corner joint portion and a T-joint portion shown in FIG. 2 was manufactured. The manufacturing conditions were the same as in Example 1 including the steps of laser welding and immersion in an acidic solution.

  Table 4 shows the result of measuring the temper color situation and 60 degree glossiness. In the surface state without the temper color, the 60 ° gloss was 75 or less, and in that state, the antiglare property was also secured.

DESCRIPTION OF SYMBOLS 1 Stainless steel laser welded shape steel including a square joint part 2 Flange material 3 Web material 4 Laser beam 11 Stainless steel laser welded shape steel 21 including a square joint part and a T-shaped joint part Stainless steel product including a square joint part Laser welded shape steel 22 Flange 23 Web 24 Welded portion 25 Region near the welded portion or the back surface of the welded portion 31 Stainless steel laser welded shape including a corner joint portion and a T-shaped joint portion 32 Flange 33 Web 34 Welded portion 35 Area θ near the weld or on the back of the weld θ Irradiation angle of the laser beam 4

Claims (6)

  A stainless steel laser welded shape steel comprising a stainless steel plate and having a square laser welded joint made of a web material and a flange material, and having a surface 60 ° glossiness of 75 or less.   The laser-welded section made of stainless steel according to claim 1, wherein the laser-welded section is a section having a square joint and a T-shaped joint as a laser-welded joint made of a web material and a flange material.   As stainless steel plate, C: 0.025 mass% or less, Si: 0.60 mass% or less, Mn: 1.00 mass% or less, P: 0.040 mass% or less, S: 0.020 mass% or less, Ni : 0.60% by mass or less, Cr: 16.00 to 35.00% by mass, Mo: 0.30 to 6.00% by mass, and N: 0.025% by mass or less. The laser-welded section made of stainless steel according to claim 1 or 2.   Further, Nb: 0.10 to 1.00% by mass, Ti: 0.05 to 0.30% by mass, Al: 0.01 to 0.50% by mass, including one or more kinds. 3. A laser-welded section made of stainless steel as described in 3.   When manufacturing a welded steel with a square welded joint formed of a web material and a flange material using a stainless steel plate, a laser welding method of irradiating a laser beam is used as the welding method, and it is immersed in an acidic solution after welding. A method for producing a stainless steel laser-welded section. When manufacturing welded steel with a square and T-shaped welded joint formed of a web material and a flange material using a stainless steel plate, a laser welding method of irradiating a laser beam is used as the welding method, and the steel is acidic after welding. A method for producing a laser-welded section made of stainless steel, which is immersed in a solution.

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