JPH05329506A - Production of vibration damping structure having high toughness - Google Patents

Abstract

PURPOSE:To provide the process for production of the structure having excellent toughness and vibration damping performance. CONSTITUTION:An ingot or slab having a compsn. contg. <=0.005% C, <=0.04% Si, <=0.20% Mn, <=0.10% A and <=0.004% N is heated to 1050 to 1250 deg.C and is hot rolled at >=750 deg.C finishing temp. to a thick steel plate. The structure consisting of the thick steel plate is produced by subjecting the steel plate to stress relief annealing at 750 to 930 deg.C. Then, the vibration damping structure having the high toughness is economically produced. The objective structure is effective for preventing the noise and vibration of traffic organs, factories and construction site.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a vibration damping structure having high toughness.

[0002]

2. Description of the Related Art In recent years, the influence of noise from transportation such as automobiles, railroads and vehicles, noise from factories and construction sites, or vibrations on nearby residents has become large every day, and has become a major social problem.

As one means for solving the problem, research and development of a vibration absorbing material in which the material itself has a vibration absorbing ability has been advanced, and a vibration damping material having a high vibration absorbing property and suitable for an application is used for a vehicle,
It is used as a structural material for ships, industrial machines, iron bridges and the like, and with further expansion of applications, not only a damping material using a conventional thin plate as a skin plate but also a damping structure using a thick plate is required.

[0004]

By the way, in such a structure, welding and working are generally carried out in manufacturing, but since this lowers the toughness, the stress relief annealing is necessary for the structure made of a thick plate. ..

In the conventional resin sandwich type vibration-damping steel plate, it is impossible to perform heat treatment after welding because the resin is heated to a high temperature to be deteriorated and the resin is peeled off by working. Therefore, there is a strong demand for a method of manufacturing a structure that can withstand this heat treatment.

The present invention has been made in view of the above problems,
Provided is a method for manufacturing a structure that can be surely subjected to stress relief annealing and has excellent toughness and vibration damping performance.

[0007]

The present invention, in% by weight, is C: 0.005% or less Si: 0.04% or less Mn: 0.20% or less Al: 0.10% or less N: 0.004 % Or less, and a steel slab or a slab having a composition of the balance iron and unavoidable impurity elements is heated to 1050 to 1250 ° C. and hot rolled at a finishing temperature of 750 ° C. or higher to form a thick steel plate. , A structure made of the thick steel plate at 750 to 930 ° C.
It is a method of manufacturing a vibration damping structure having high toughness, which is subjected to stress relief annealing at.

[0008]

The operation of the present invention will be described in detail below.

The thick steel plate that constitutes the vibration damping structure is required to have high toughness and high vibration damping performance after the structure is manufactured. The present inventor has conducted various studies in order to satisfy both of the above, and newly obtained the following findings to achieve the present invention.

That is, with respect to the former high toughness, stress relief annealing is effective for eliminating the residual stress when the structure is processed and welded. Regarding the damping performance of the latter,
It was found that it is important to coarsen ferrite crystal grains by stress relief annealing to secure high toughness after manufacturing the structure.

The disorder of the magnetic domain (spike magnetic domain) generated at the grain boundary due to the coarsening of the crystal grain is reduced, the magnetic domain / domain wall structure is arranged in order, and the domain wall is easily moved. It was found that when the members of the structure are deformed, the magnetic domain walls easily move to absorb the vibration energy and attenuate the vibration, thereby improving the vibration damping performance.

Further, it is necessary to coarsen the crystal grains to the limit,
It was found that the structure has high toughness and high vibration damping performance after being stress-relieved and annealed.

In order to further coarsen the crystal grains to the limit, by reducing various constituent elements such as C, Si, Mn, and N to the limit, stress relief annealing can be performed to remove strain in the constituent members of the structure. A large ferrite grain growth can be achieved. As a result, the vibration damping performance is improved.

Next, the stress relief annealing is carried out after the structure is manufactured by welding and bending to remove the residual stress sufficiently, and at the same time, the grain size of the crystal grains is increased during the heating process and the holding process at the maximum temperature of this heat treatment. This is for coarsening and improving the vibration damping performance. For this purpose, it is necessary to perform stress relief annealing in an appropriate temperature range.

In FIG. 1, 0.003% C-0.03% Si-
The effect of stress relief annealing temperature on the loss factor in 0.13% Mn-0.0032% N steel is shown. The stress relieving annealing temperature needs to be 750 ° C. or higher for coarsening the crystal grains, and if annealing is performed at higher than 930 ° C., the crystal grains are rather refined due to the transformation and the loss factor is lowered. Therefore, the temperature range is set to 750 to 950 ° C.

Next, the reasons for limiting the components will be described.

C is an element that makes the movement of the domain wall difficult and reduces the vibration damping performance, and it is necessary to suppress it as much as 0.0.
The upper limit is 05%.

Si is an element that makes it difficult to move the domain wall and lowers the vibration damping performance. Since it is necessary to suppress it as much as possible, the upper limit is 0.04%.

Mn is an element that lowers the vibration damping performance, and it is necessary to suppress it as much as possible, so the upper limit is 0.20%.

Al is an element necessary for deoxidation, but 0.1
If added over 0%, the toughness decreases, so the upper limit is made 0.10%.

N makes it difficult to move the domain wall,
It is an element that lowers the vibration damping performance, and it is necessary to suppress it as much as possible, so 0.004% is made the upper limit.

In addition, P, S and the like may be contained as an unavoidable impurity element, but the smaller the content of these elements, the better the toughness.

In melting this steel, an electric furnace,
Any of the converters may be used. When making a steel plate,
When the heating temperature of hot rolling is less than 1050 ° C or the rolling finishing temperature is less than 750 ° C, the vibration damping performance is lowered due to the refinement of crystal grains. Also, heating above 1250 ° C
In order to increase the fuel cost and the maintenance cost of the furnace, the heating temperature is set to 1050 to 1250 ° C and the rolling finishing temperature is set to 750 ° C or higher.

The stress relief annealing after the structure is manufactured by welding and bending is sufficient to remove the residual stress, and at the same time, the heat treatment is performed to coarsen the crystal grains and enhance the vibration damping performance. So that the temperature is in the range of 750 to 930 ° C.

[0025]

EXAMPLES Of the chemical components shown in Table 1, 1-3 are examples of the present invention, and 4-13 are comparative examples. Steel was melted by a converter, made into a slab, and then heated and rolled as shown in Table 1 to manufacture thick steel plates. Further, a thick steel plate was welded to produce an H-shaped structure, and then stress relief annealing was performed if necessary.

Table 1 also shows the loss factor of the above structure and the Charpy impact test value.

In Examples 1 to 3 of the invention, heating, rolling, and stress relief annealing for reducing the vibration damping performance-inhibiting elements such as C and N, and for coarsening the crystal grains to the limit are appropriate. It has a high loss coefficient, good vibration damping performance, and high toughness.

Next, as comparative examples, Example 4 has a high C content, Example 5 has a high Si content, Example 6 has a high Mn content, and a low loss coefficient.
Example 7 has a high Al content, a low loss coefficient, and a low toughness. Example 8
Has a high N, Example 9 has a low heating temperature, and Example 10 has a low rolling finish temperature and a low loss coefficient. Since Example 11 has no heat treatment, it has a low loss coefficient and low toughness. Example 12 has a low annealing temperature, and Example 13 has a high stress relief annealing temperature and a low loss coefficient.

[0029]

[Table 1]

[0030]

As described above, according to the present invention, by appropriately reducing the vibration damping performance inhibiting element and performing the appropriate heating, rolling and stress relief annealing in order to coarsen the crystal grains to the limit, It is possible to economically manufacture a vibration damping structure having high toughness, and has a great effect on preventing noise and vibration in transportation facilities, factories and construction sites.

[Brief description of drawings]

FIG. 1 is a drawing showing the effect of stress relief annealing temperature on loss factor.

Claims (1)

[Claims] 1. By weight%, C: 0.005% or less Si: 0.04% or less Mn: 0.20% or less Al: 0.10% or less N: 0.004% or less, and the balance iron And a steel slab or a slab having a composition consisting of unavoidable impurity elements are heated to 1050 to 1250 ° C., and hot rolled at a finishing temperature of 750 ° C. or higher to form a thick steel plate, and a structure made of the thick steel plate. 750-930 ° C
Of manufacturing a vibration-damping structure having high toughness in which stress-relief annealing is performed at high temperature.