JP2740074B2 - High tensile strength column material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high tensile strength column material,
More specifically, the tensile strength is 490 N (50 kgf / m
The present invention relates to a high tensile strength column member comprising a high tensile strength cast steel having a welded portion to which m ² ) or more beam members are welded and having a carbon equivalent of 0.44 or more.

[0002]

^2. Description of the Related Art In recent years, as a column material supplied for building construction, a high tensile strength column material having an extremely high tensile strength of 780 N (80 kgf / mm ² ) class has been used. Since this high tensile strength column material contains a considerable amount of chemical components such as Ni, Cr, and Mo, the carbon equivalent Ceq (weight) calculated based on the following formula (i) (for example, see JIS G 5102). %) Was as high as 0.44 or more, and the weldability was very poor. Ceq = C + Mn / 6 + Si / 24 + Ni / 40 + Cr / 5 + Mo / 4 + V / 14 (i) In the formula (i), C, Mn, Si, Ni, Cr, M
o and V indicate the content (% by weight) of each chemical component in the high tensile strength column material, respectively. The high tensile strength column member has a welded portion formed in, for example, a flange shape, and the welded portion has a beam having a tensile strength of 490 N or more (specifically, JIS standard: SM490 (former SM50)). )
And the like, a beam material made of a rolled steel material for a welding structure. By the simple welding of the beam to the high tensile strength column material, the carbon equivalent of the high tensile strength column material is extremely high at 0.44 or more as described above. Since the metal structure is a cast structure with coarse crystal grains, weldability is always a problem, for example, welding cracks such as toe cracks are likely to occur at welding locations (including heat affected zones). Therefore, conventionally, in order to prevent the occurrence of the welding crack or the like, an appropriate pre-heat treatment (for example, 10
(Preheating to 0 to 250 ° C.). Also,
Since a large internal stress (residual stress) is generated at the welding location, an appropriate post-heat treatment (for example, a process of post-heating to 500 to 650 ° C.) is performed at the welding site to remove the internal stress. Was.

[0003]

However, in order to carry out the pre-heat treatment and the post-heat treatment at the welding site, a gas burner for heating the welding point is arranged near the welding point, or the gas is burned. Usually, it is necessary to perform troublesome work, such as wrapping a heating element to be heated around the welded part, or wrapping a heat insulating material around the welded place so that heat does not escape, which has to rely on manual labor. There was a problem that sex was extremely bad. Further, since the place where the processing is performed is usually a place where the height from the ground is several tens of meters and a dangerous work is forced, the workability is further improved from the viewpoint of poor working environment. There was a problem of getting worse. The present invention has been made in view of such a situation, and an object thereof is to provide means capable of solving the above-described workability problem when welding the beam material to the high tensile strength column material. It is in.

[0004]

The high tensile strength column material according to the present invention has a welded portion to which a beam having a tensile strength of 490 N or more is welded, and is made of a high tensile strength cast steel having a carbon equivalent of 0.44 or more. A tensile strength column material, and on the surface of the to-be-welded part, a carbon-equivalent portion having a carbon equivalent of 0.40 or less and a tensile strength of 490 N or more is provided in advance, and at the time of attaching the bulky portion. It is characterized in that a heat treatment for removing generated internal stress has been performed in advance.

[0005]

According to the present invention, the high tensile strength column material of the present invention
When the beam material is welded, the welded portion is pre-attached to the welded portion (that is, a welded portion having a carbon equivalent of 0.40 or less and having good weldability), and Since the heat treatment is performed in advance, at the welding site,
Weldability is good, and only the welding of the portion of the thickened portion and the beam material having a small residual stress is required to be performed,
Pre-heating and post-heating work conventionally required at a welding site becomes unnecessary. In addition, both the work of providing the thickened portion and the work of performing the heat treatment can be easily performed in a place having a favorable working environment (for example, a welding factory) before shipping the high tensile strength column material. Further, the material of the fleshed portion has a tensile strength of 490.
Since the steel material is limited to N or more, the mechanical strength of the beam joint part, while partially including the material of the flesh portion different from the beam material or the column material, the beam material or the column It becomes comparable to the mechanical strength of the material, and the strength of the beam joint does not become insufficient.

[0006]

Therefore, by using the high tensile strength column material according to the present invention, the problem of workability, which has been a problem in the past, can be solved without generating a new problem. The object of the invention will be achieved.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows, for example, a high tensile strength column made of a centrifugal cast steel tube obtained by centrifugally casting a high tensile strength cast steel having a tensile strength of 780 N class. As shown in FIG. 2, a material 1 is provided with a welded portion 2 to be welded (specifically, a welded portion 2 formed in a flange shape). Incidentally, the formation of the welded portion 2 is as follows.
In the process of the centrifugal casting, it is performed simultaneously with the formation of the steel pipe.

Since the high tensile strength column material contains a considerable amount of chemical components such as Ni, Cr and Mo, the above formula (i) is used.
Of carbon equivalent Ceq (% by weight) calculated based on
4 or more, which is very high, and the weldability is very poor.

Therefore, in the high tensile strength column material of the present invention, on the surface of the to-be-welded portion 2, a fleshy portion 3 made of a steel material having a carbon equivalent of 0.40 or less and a tensile strength of 490N or more is provided in advance. I have.

[0010] Specifically, in the factory (for example, a welding factory) where the working environment is good, the overlaid portion 3 is built-up welding using a welding rod made of the steel material (more specifically, MIG).
It is provided by performing overlay welding (automatic welding).

Further, in a factory having a good working environment, a heat treatment for removing internal stress generated at the time of attaching the fleshy portion 3 is also performed. In the case where the heat treatment is simple, the heat treatment is performed by heating the welded portion of the high tensile strength column material with a gas burner and maintaining the temperature. When strict heat treatment is required, the heat treatment is performed using a heat treatment furnace. For example, when a heat treatment furnace set to a furnace temperature suitable for the heat treatment is provided, the high tensile strength column material in a state of several pieces is charged into the heat treatment furnace,
It is carried out by holding it in the furnace for an appropriate time. Also,
When the number of treatments of the high tensile strength column material is particularly large, continuous treatment using a tunnel-type continuous furnace may be considered.

Next, another embodiment will be described. In the above embodiment, the thickened portion 3 is provided by welding and overlaying the steel material. However, the steel material (that is, the carbon equivalent is 0.40 or less and the tensile strength is 4
Spraying a thermal spray material consisting of 90N or more steel material)
Various types of filling methods, such as welding a ring made of the above steel material (that is, a steel material having a carbon equivalent of 0.40 or less and a tensile strength of 490 N or more) are considered. In addition, the said flesh part 3
After the formation, the machined portion 2 is appropriately machined as necessary.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a high tensile strength column material according to the present invention.

FIG. 2 is a side view showing a beam-column joint using the high tensile strength column material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Beam material 2 Welded part 3 Filled part

Claims (1)

(57) [Claims] 1. A high tensile strength column member comprising a high tensile strength cast steel having a welded portion (2) to which a beam (1) having a tensile strength of 490 N or more is welded, and having a carbon equivalent of 0.44 or more. On the surface of the to-be-welded part (2), a thickened part (3) made of a steel material having a carbon equivalent of 0.40 or less and a tensile strength of 490N or more is provided in advance, and the thickened part (3) is provided. High tensile strength column material that has been heat-treated in advance to remove internal stress that sometimes occurs.