JPH0788644A - Method for welding joint core of square steel tube without need of backing strip - Google Patents

Abstract

PURPOSE:To form a uniform, high quality and high precision joint material by improving a butt welding means, automatically assembling a column beam joint material by an economic means and forming a welded joint with a large penetration. CONSTITUTION:One of the opening ends of a core 2 which is beveled at the outside of the end edge is placed on a diaphragm 1 with a hole provided with a required diameter in the center, and both are tack-welded 4. Simultaneously, the abutting faces of the core inner walls are welded by CO2 arc welding, and a layer welding joint 5 is formed. Then, the core is rotated by a 180-degree, the other opening end face of the core 2 is placed on the other diaphragm 6, and both are tack-welded. A welding means is inserted from the center hole of the diaphragm 1; and after the abutting faces of the inner walls are formed into a one layer welding joint 5 by CO2 arc welding, the abutting part between the diaphragm and the outer circumference of the end face of the core 2 is subjected to laminating welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The welding method according to the present invention is used for assembling a dice-type rectangular steel pipe and a diaphragm at the time of assembling a bracket-type structure of a "column beam joint" forming a joint between a steel pipe column and a beam material. Butt welding, that is, a method of welding a square steel pipe joint core that does not require a backing metal.

[0002]

[Prior Art] The "column beam joint part" has the axial force of each member.
Since the bending moment and shear stress are concentrated, the joint material is designed to have sufficient proof strength and rigidity.
It must be configured to ensure safety against local damage to the column peripheral wall caused by the strength of beam-welded joints, shear strength of joint panels, bending stress of beams, and the like.

[0003] The column beam joint material is roughly classified into a fastener joint using bolts / high-strength bolts and the like, and a weld joint, depending on the joining method. In a structure using a steel pipe column, the member cross section is a closed type fastener. Welding is generally adopted because joining is not easy, and the factory-welded bracket-type column beam joint material has been evaluated in terms of workability and reliability, as it meets the above conditions. Widely used from.

By the way, of the above-mentioned bracket type column beam joint members, in order to form a beam penetrating type through diaphragm joint member, conventionally, a rectangular steel pipe column is short in the longitudinal axis direction and perpendicular to the longitudinal axis. After forming a dice-shaped member (hereinafter referred to as a core) 2 by cutting in the direction, the outer circumference of each opening end face is groove-processed, and a backing metal is temporarily welded along the inside of each core end face without gaps. After forming the root gap, the diaphragm 1 is placed on the root gap, and a joint is formed in the weld pocket formed between the groove-processed portion 3 of the core end surface and the surface of the diaphragm. Was being assembled.

Of the above-mentioned assembling processes, the butt main welding process between the core 2 and the diaphragm 1 has recently been made, and automation has become possible almost in the factory based on the remarkable progress of welding robot technology. Uniform product quality,
It has become possible to improve precision and improve machining efficiency. However, the step of temporarily welding the backing plate to the end surface of the core, which is a preliminary work of the above-described main welding, is difficult to unconditionally automate.

That is, if there is a gap between the backing plate and the inner peripheral surface of the core 2, "leakage" of the weld metal occurs during the main welding between the core 2 and the diaphragm 1, and the fillet weld joint Although the quality of the core is adversely affected, the tolerance of the core 2 cross-section molding standard is so small that even if a backing metal of the same shape is applied to the inside of the end surface of the core, the backing metal does not adhere to the inner peripheral surface of the core. There is a problem. Therefore, it is necessary to use a hammer or a vise to manually perform temporary welding while aligning the backing plate with the inner peripheral surface of the core.This type of work does not adapt to automation, and man-hours and labor costs increase at present. is there.

Along with this, in the conventional method, (1) the backing plate is made to protrude from the end face of the core by 5 mm to 10 mm and temporarily welded to form a root gap at the end edge of the core. It is difficult for the end surface of the backing plate to be placed on the same plane in the attachment welding, and a gap is formed between the end surface of the backing plate and the surface of the diaphragm 1, which adversely affects the quality of the welded joint. Or, the assembling accuracy of the joint material is lowered. (2) In particular, welding defects are likely to occur at the corner R portion. (3) Since the welding pocket is large, the heat capacity of the molten metal is large, and in addition to that much welding material is used,
The local strain due to the heating of the base material is naturally large.

(4) After the welded joint is formed, the gap between the backing metal and the inner peripheral surface of the core becomes a crack in the welded joint, which adversely affects the strength of the joint. (5) When ultrasonic flaw detection is performed on the welded joint, the backing metal may appear as a pseudo echo, which may make the determination difficult. Including problems such as. Therefore, recently, for the purpose of automatically assembling members of this type, a butt welding method has been proposed which does not require a backing metal for joining the core and the diaphragm.

For example, when butt-welding a core whose outer end face is grooved at a predetermined angle to a diaphragm, a gap of 2 to 5 mm is provided from the inner end face of the core while sensing the inner surface shape of the core to form a diaphragm face. Dielectric beads formed by padding are used instead of the conventional backing metal, and the appropriate root face and root gap are formed by assembling and positioning the core end surface with the groove surface on the outside at the above-mentioned location. Has developed a dielectric bead method characterized by continuously performing carbon dioxide arc welding or layered welding such as inner gas welding.

The above-mentioned construction method improves on the above-mentioned problems inherent in the conventional method for assembling and welding the joint material, and the function of the backing plate at the time of butt welding is substituted by the dielectric beads preliminarily built up on the diaphragm. Since the welding pocket formed at the butt part is carbon dioxide gas welded or inner gas welded, the inner surface shape of the core is sensed and the dielectric bead is built up. Gaps and root faces are obtained, and welding quality is stable. With the positioner, it is possible to maintain and control the proper welding posture, complete welded layered welding, and no welding defects occur.

Since no backing metal is used, a false echo does not occur during ultrasonic flaw detection, and defects can be easily detected. Welding amount is 70-80% compared to the conventional method (with backing plate)
Therefore, the welding material is saved and the welding distortion of the diaphragm is reduced. Compared with the conventional construction method with backing metal, the cost can be reduced significantly. It has become a thing.

However, even in the above method, the work for (a) overlay welding the dielectric bead to the diaphragm in conformity with the shape of the inner wall of the core takes a relatively long time and is not efficient. (B) The consumption of welding materials for that is not small. (C) The welded joint inside the core is easily undercut. Etc. Problems have not been resolved.

[0013]

SUMMARY OF THE INVENTION The object of the method of the present invention is to solve the above problems and to provide a reliable welded joint in the welding and assembling of a square steel pipe joint core which does not require a backing metal. To provide a welding method of a joint core suitable for automatic assembly processing.

[0014]

In order to achieve the above-mentioned object, the method of the present invention has the respective constituents described below. (1) When butt-welding a dice-type square steel pipe whose outer end face is grooved at a predetermined angle to a diaphragm having a required hole in the center, the end face of the steel pipe is brought into contact with the diaphragm and a temporary gap between them is provided. Welding welding, and installing the diaphragm horizontally, after forming the one-layer weld joint by welding the entire circumference of the diaphragm butt portion of the steel pipe end surface from the inside of the steel pipe by carbon dioxide arc welding, reverse the work material, Place the symmetrical end surface on another diaphragm and temporarily weld them together, insert the welding means from the diaphragm central opening, and weld the entire circumference of the diaphragm abutting part on the inner end surface of the steel pipe by carbon dioxide arc welding to further weld. After forming a joint, and then scraping off the tack welded part, set one of the butt groove faces on the outside of the steel pipe to face upward and set the part outside the steel pipe. Butt welding is performed from the side by carbon dioxide arc welding, and one of the other outer groove faces is set upward in sequence, and the welding is continuously repeated to complete the entire circumference of the diaphragm butted portion on the outer circumference of the steel pipe. A method for welding rectangular steel pipe joint cores, which does not require a backing metal, which comprises forming a butt-welded joint on the surface.

[0015]

[Operation] On the first diaphragm having a hole of the required diameter L at the center, the opening of the core (dice type square steel pipe) with the groove on the outer circumference of the end face is placed, and they are positioned with respect to each other and temporarily Attach and weld. (Usually) Welding means is inserted inward from the core opening on the opposite side, the welding electrode is moved with the inner wall surface of the core as a guide (or by automatic control), and CO ₂ ( Carbon dioxide) arc welding for further fillet welding. The second diaphragm is placed on the other end (opposite side) of the core opening, and the same processing as described in the above paragraph is repeated, and the central hole (diameter = diameter) of the first diaphragm attached to the core by the processing in the above paragraph is repeated. Insert the welding means from L) inside and use the inner wall surface of the core as a guide (or by automatic control)
The electrode is moved, and the entire inner circumference of the butt portion between the core and the second diaphragm is further welded by CO ₂ arc welding.

[0016] While removing the tack welded portion described in paragraphs (1) and (2), while rotating the core while keeping the core central axis almost horizontal, the butt welding pocket formed by performing the groove processing on the outer periphery of the core end surface is directed upward. Continuous laminated fillet welding is performed including the corner R portion. The above-mentioned welding can be performed on each side or simultaneously on both sides. Thus, it is possible to form a joint member for a square steel pipe provided with a butt-welded joint for inner and outer surface welding, which has good penetration and has few welding defects.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the above-mentioned method of the present invention will be described with reference to the drawings. However, each requirement of the embodiment described below is within the range of the technical level known in the art at the time of filing the present invention. Since various modifications can be made by those skilled in the art, the gist of the present invention should not be construed in a limited manner based on only the specific configuration described in the present embodiment without showing any special reason. Now
A preferred or typical embodiment of the method of the present invention will be described below.

FIG. 1 shows a sectional structure of the first step of the butt welding process of the diaphragm 1 and the core 2 opening end surface of the joint member formed by the method of the present invention. In the figure, the material of the diaphragm 1 is, for example, SS400, SM490A, and the plate thickness t is 12 to
32mm. In the center of diaphragm 1, diameter L is about 200
Provide a hole of mmφ. Since the hole is a space used for inserting the welding means from the hole to filletly weld the inner surface abutting portion between the core 2 and the opposing diaphragm 1, the hole diameter L needs to be different depending on the core diameter. There is. The material of the core 2 is, for example, SS400, SM490A, the plate thickness t is 12 to 32 mm,
The core diameter is 300-600 mm. Reference numeral 3 denotes an opening end face groove portion of the core 2, which is a groove portion of about 35 ° in the present embodiment.
This portion may have a 45 ° groove. The root face provided on the end face is 2-3 mm.

(A) The root face is placed on the surface of the diaphragm 1 by metal touch, and at this time, the core 2 and the diaphragm 1 are positioned relative to each other. Four
Is a temporary welding for fixing the relative position between the abutting portion of the core 2 and the diaphragm 1 and is usually spot welding. (B) 5 shows a single layer fillet welded joint of the butt inner surface of the core end surface and the diaphragm. The fillet joint 5 is formed continuously over the entire circumference by upward welding CO ₂ arc welding by inserting welding means through the core opening, moving the inner wall of the core as a guide. Of course, the butt welding may be inert gas arc welding.

FIG. 2 shows a schematic sectional view of the second step. (C) The workpiece shown in FIG. 1 is rotated 180 ° so that the other opening end face of the core faces downward and is placed on the diaphragm 6. Place with a metal touch, and tack weld them together as in (A) above. (D) Welding means is inserted through the central hole of the diaphragm 1 having a diameter of 200 mm, and the butt portion between the core and the diaphragm 6 is welded upward with the inner wall of the core 2 as a guide, as in the case of (B). At the time of welding, if it is difficult for the gas nozzle to reach the corner of the inner wall of the core with the central hole of the 200 mm diameter diaphragm, expand the central hole to the required diameter.

FIG. 3 shows a schematic cross-sectional view of the third step. (E) Each tack welding 4 part is removed by gouging. (F) The center axis of the core is held horizontally and hung on an automatic copy welding device to maintain a proper welding posture, while continuously welding from the outside of the core to the welding pocket formed in the abutting portion to form a stacking corner. The meat welded joint 7 is formed. The fillet welding may be performed on each of the diaphragms 1 and 6 separately or simultaneously.

(G) As described above, after the relative position of each material is determined and set in the automatic copying welding device, the welding formed on the butt portion from the outside of the core while maintaining the proper welding posture by the positioner. The gas shield type automatic arc welding in which the inert gas in MIG welding is replaced with carbon dioxide gas is applied to the pocket, and the butt (automatic) laminated welding in which the corners of the core are also continuous is performed so that there is no defect in fillet welding. A joint is obtained.

[0023]

Since the method of the present invention is as described above, it is possible to provide a high-quality and stable product by accommodating any of the steps to automation, eliminating the problems inherent in the conventional manufacturing method. it can. By implementing this method, the backing metal is not used, so the steel material cost is not incurred.

High efficiency can be maintained without the need to manually attach the backing plate and the construction cost. Since the core and the diaphragm are metal-touched, the assembly dimensional accuracy is significantly improved. Welding inside the core can be automated. Since it is a welding process with no root gap, the welding pocket is narrow and the amount of welding is reduced to 60% compared to conventional products.
Therefore, welding materials are reduced. The amount of welding is smaller than that of the conventional method (with backing plate), the distortion of the diaphragm due to welding is small, and the welding time is short.

Welding defects are less likely to occur at the corner R portion. Since there is no backing metal, pseudo echo does not occur when inspecting welded joints for defects, and defects can be detected and judged very easily. According to the method of the present invention, welding man-hours, working man-hours, and assembling man-hours can be significantly reduced as compared with the conventional beam-through / through-diaphragm type molding, and the number of work-in-process days from order receipt to shipment can be shortened. be able to. Moreover, it is possible to provide an epoch-making construction method that facilitates automatic assembly and further improves the mounting accuracy.

[Brief description of drawings]

FIG. 1 shows a cross section of a first step of butt welding of a diaphragm and a core end surface of a joint member formed by the method of the present invention.

FIG. 2 shows a cross section of a second step of molding a joint material by the method of the present invention.

FIG. 3 shows a cross section of a third step of forming a joint member by the method of the present invention.

[Explanation of symbols]

 1,6 Diaphragm 2 Core 3 Beveled part 4 Temporary welding 5 Inner layer single layer butt weld joint 7 Laminated butt weld joint.

Claims (1)

[Claims] 1. When butt-welding a dice-type rectangular steel pipe whose outer end face is grooved to a predetermined angle to a diaphragm having a required hole in the central portion thereof, the end face of the steel pipe is brought into contact with the diaphragm so that the space between them is increased. Temporarily welded, while installing the diaphragm horizontally, after forming a further welded joint by welding carbon dioxide gas arc welding the entire circumference of the diaphragm butt portion of the steel pipe end surface from the inside of the steel pipe, reverse the work piece, Place the symmetrical end surface of the steel pipe on another diaphragm and temporarily weld them together, insert the welding means from the diaphragm central opening, and weld the entire circumference of the diaphragm abutting part of the inner end surface of the steel pipe by carbon dioxide arc welding. After forming a one-layer welded joint, and then scraping off the tack welding point, set one of the butt groove surfaces on the outer side of the steel pipe to face upward. Butt welding is performed from the outside of the steel pipe by carbon dioxide arc welding, and one of the other outer groove faces is sequentially set upward, and the welding is repeated continuously to complete the entire butt of the diaphragm on the outer periphery of the steel pipe. A welding method for a rectangular steel pipe joint core which does not require a backing metal, which is formed by forming a butt-welded joint on the circumference.