JPS5945748B2 - Damping steel plate for processing and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a split steel plate that has good formability and exhibits an extremely high vibration damping ability after forming, and a method for producing the same.

In recent years, vibration pollution and noise pollution from transportation facilities, machine factories, etc. have become a problem, and reductions in these vibrations and noises have been demanded from various fields, and various countermeasures are being considered.

In order to reduce such vibrations and noise, it is necessary to eliminate the vibration of the object that is the source of the sound, and to do this, it is necessary to design the machine so that its structure does not resonate. Although it is said to be the most effective countermeasure, the actual noise sources, vibrations, are complex and it is difficult to eliminate them.

Therefore, it has been desired to prevent vibration generation by using a material with high vibration damping ability in the noise generating portion.

Conventionally, Mn--Cu alloys have been commercially available as such allocation materials, but this alloy has the drawbacks of low Young's modulus and high manufacturing costs.

In addition, high Cr steel is also known as an alloy with high vibration damping ability, but it also has problems such as high cost and the fact that its vibration damping ability is significantly reduced by cold working. is limited to special uses.

In addition, flake graphite cast iron also exhibits high vibration damping capacity, but this is a material that is almost impossible to work with, further limiting its use.

On the other hand, against this background, a vibration damping steel plate was proposed, which is made of an inexpensive wrought iron material and has improved vibration damping ability by increasing its grain size. In a low distortion amplitude range (treble range) in which 10-5 or less, it is difficult to obtain high vibration damping ability, and there is a problem that the vibration damping ability is likely to decrease due to cold working.

Furthermore, by incorporating a large amount of inclusions such as oxides into iron-based materials to increase cleanliness, and by combining short-time annealing and cold working, micropores are created at the interface between the inclusions and the base iron. A method has also been proposed to improve the vibration damping ability of such materials, but such materials generally do not have very high vibration damping ability, tend to deteriorate over time, and have extremely poor workability due to their high cleanliness. There was a problem.

From the above-mentioned viewpoints, the present inventors aimed to produce a material that has good workability, does not deteriorate in vibration damping ability even with subsequent processing or aging, and has an extremely high vibration damping ability. As a result of the research, the following (a) to (f)
).

That is, (a) the sound insulation and vibration damping performance of a steel plate is expressed by the magnitude of the steel plate's internal friction δ Q-1 (where Q-1 = -, δ is the logarithmic damping rate) π, which is the strain amplitude It refers to the amount of energy lost per cycle, and the larger Q-1 is, the greater the rate of converting vibration energy into heat inside the steel plate, and the vibration damping effect can be improved.

In general, by reducing the solute carbon and nitrogen in iron to facilitate domain wall movement, it is possible to produce an alloy with high vibration damping ability due to magneto-mechanical static hysteresis loss. Friction is greatly affected by strain and internal stress, and even a small amount of cold working significantly reduces its vibration damping ability.

However, when there is a moderate amount of sulfide extended in the rolling direction in the steel and there are almost no C and N solid solution atoms in the steel, cold working (especially tensile deformation) Vibration damping ability is significantly improved.

Note that the above sulfide is preferably MnS-based, but MnS, Ti
A mixture of S, Nb5STaS, ZrS, or a compound containing 0□, A12, Fe, Si, etc. may be used.

However, it is desirable to have inclusions that are difficult to melt during the manufacturing process of steel sheets and easy to expand during hot rolling (A-type or B-type inclusions). The requirement that the iron be clean with extremely low C and N content must be intertwined with the presence of a specific second phase. For example, if the second phase is only TiC or AIN, the heat Most of it melts during heating during rolling, and if the second phase is only Al2O3 or TiN, it is difficult to expand it by rolling, and in either case, the effect of improving vibration damping ability is very low. to small things.

(b) In order to reduce C and N, which are penetrating solid solution elements in steel, it is sufficient to add strong carbonitrides to fix C and N, for example, AI, V, and Cr. The effect is not sufficient when adding Ti, Nb,
Ta and Zr exhibit excellent effects.

Moreover, among these, Ti is the most effective, and since it is easy to add and has a low cost, Ti alone is added only in an amount sufficient to fix C and N, that is, C (%
)/12+N(%)/14.

(In addition, the percentages related to the added elements are hereinafter referred to as weight percentages.) (c
) Even if Si, which improves strength, is added as necessary to steel that has improved vibration damping ability by making a sulfide phase exist in the steel and reducing penetrating solid solution elements, vibration damping will not be improved. Please do not have any negative impact on Noh.

(d) The vibration damping ability exhibited by such a sulfide phase does not deteriorate over time.

(e) Such a steel plate has good strain propagation during forming, so it is less likely to crack or break, and has good workability.

(f) When hot rolling such a steel material, if the tube heating temperature is lower than that in normal hot rolling, the vibration damping ability increases, and therefore the vibration damping effect increases.

Therefore, this invention was made based on the above knowledge, and the present invention was made based on the above-mentioned findings.
: 0.05-3.00%, S: 0.038-0.2
50%, Sol, Al: 0.20% or less, N: 0.
020% or less, and further contains 1.0% or less of 'l
'i, 1.0% or less Nb, 1.0% or less T
a.

Contains 1.0% or less of Zr, one or more of the following, the total amount of which satisfies the formula: Fe and unavoidable impurities: the remainder, and the composition is as follows. Or, in addition to this, these steel sheets are characterized by containing 3% or less of Si to impart excellent vibration allocation performance and good workability. Steel with a composition matching that of
℃ and then hot rolling, or furthermore, the steel plate obtained by this hot rolling is pickled, cold rolled at a rolling reduction of 20% or more, and then box annealed or continuous annealed. This method is characterized by obtaining a steel plate with good workability and excellent vibration damping performance.

Next, the reason why the amounts of each component of the steel plate of the present invention, the heating temperature of the slab during manufacturing the steel plate, and the rolling reduction ratio of cold rolling are limited as described above will be explained.

(a) C The lower the C content, the better, but the lower limit of 0.002% is the lower limit of the C content of steel that can be easily produced by top-blowing converters, bottom-blowing converters, vacuum degassing, etc. And so.

On the other hand, if the C content is high, the amount of carbides will increase, which will have a negative effect on workability, and it will also be necessary to add large amounts of 'ri, Nb, Ta, and Zr, resulting in high costs. , what happened to oso%?

(b) Mn The Mn component is the cheapest sulfide-forming element, and should be added in an appropriate amount depending on the manufacturing conditions of the steel sheet. However, if its content is less than 0.05%, it may be difficult to heat the slab during hot rolling, etc. Mn
S is easily dissolved, and the damping effect becomes small in this field.

On the other hand, if it exceeds 3.00%, melting in a converter becomes difficult, so the range is set to 0.05 to 300%.

In general, the lower the slab heating temperature during hot rolling, the smaller the amount of Mn. Therefore, a lower slab heating temperature is preferable in terms of cost and workability.

(d SS S component is important for forming sulfides, but if its content is less than 0.038%, the amount of sulfides produced is too small, so the allocation effect is small.

If the content is 0.038% or more, Mn
The surface area of MnS is more important than the volume fraction of S,
The more this is present, the better the allocation performance will be, but if its content is 0
．． If it exceeds 250%, especially if it exceeds 0.3%, processability will decrease, so the content of S component should be adjusted to 0.038 to 0.2.
It was set at 50%.

(d) Sol, Al 5ol, and AI are added to improve the yield of Ti1Nb, Ta, and Zr, and their content is 0.
．． If it exceeds 20%, it will adversely affect the processing method of the steel plate, so the content is set to 0.20% or less.

(e) N The smaller the N component, the better.

If the content exceeds 0.020%, Ti, Nb, T
It requires a large amount of a, and Zr, which not only increases the cost but also impairs the workability of the steel plate.

(f) Ti, Nb, Ta, Zr All of these components are strong carbonitride-forming elements.

That is, both TiC1TiN and NbC1NbN
, TaC, TaN, ZrC.

Since ZrN is formed, it is only necessary to add each of them preparatively to bind to C and N.

Therefore, the total amount must satisfy the formula: Therefore, it follows.

However, Ti in an amount exceeding 10%, Nb in an amount exceeding 1.0%, Ta in an amount exceeding 1.0%, and Zr in an amount exceeding 1.0% deteriorate the processing method of the steel plate and This is not preferable because it increases the cost.

In addition, when the amounts of Ti, Nb, Ta, and Zr are within the range of the above formula,
It also has the effect of stabilizing sulfides such as MnS, making it difficult for hot temperatures to occur even with a high S content.

(g) 5i Si is normally contained as an impurity element in an amount of 0.2% or less, and this component is added to increase the strength of the steel sheet.

The damping properties of the steel sheet of this invention depend only on the different phase of sulfide, and are completely independent of the Fe structure and grain size, so even if the above-mentioned components are added depending on the application, the damping properties will be lost. Never.

However, if Si exceeds 3%, the workability of the steel plate is adversely affected, so this value was set as the upper limit of the content.

(h3 Slab heating temperature during hot rolling The slab heating temperature during hot rolling is the normally adopted 1
200~1300℃ is fine, but this temperature is 950~118℃.
When the temperature drops to 0°C, the damping effect increases even more.

This is because the oxide is difficult to dissolve, but if the temperature is less than 950°C, rolling will occur in the α phase or α + γ phase, resulting in poor workability. The temperature was limited to a range of 950 to 1180°C.

In the case of producing a cold-rolled steel sheet, it is preferable that the slab heating temperature be within the above range.The annealing after cold rolling may be either continuous annealing or box annealing.

(i) Reduction ratio during cold rolling If the reduction ratio during cold rolling is less than 20%, the crystal grain size becomes abnormally large after annealing, which tends to cause surface roughness during cold working, resulting in poor quality of the processed product. Because it damages the surface quality,
The rolling reduction rate was limited to 20% or more.

It is not necessary to particularly perform hot rolling, cold rolling, and temper rolling after annealing.

Rolling is performed at an elongation rate of 0.3 to 5.0% when the flatness is poor, when the yield point needs to be increased, or when the user expects a distribution effect without performing much forming processing. .

The steel sheet for processing of this invention is generally rolled after casting to destroy the cast structure, so the sulfides formed in the steel are expanded and a damping effect is brought about. A similar distribution effect can be achieved with steel castings or seamless steel pipes if the amount of deformation is large.

Since welded steel pipes are manufactured from steel plates, it is natural that they have similar allocation effects.

Considering the various phenomena described above, the reason why the damping ability, that is, the damping ability of the steel sheet of the present invention is improved by cold working is due to the second effect of cold working.
It is presumed that this is due to the chord motion of dislocations formed in the iron in contact with the sulfide phase, and that damping properties are exhibited only when the amount of penetrating solid solution elements in the steel is extremely low. ,
This seems to be supported.

In addition, in manufacturing the steel plate of this invention, it is necessary to
If it is a thin steel plate below mmmm, Ti, Nb, and Ta are contained in the steel.
, and Zr, or even if their content is small, it is possible to remove C and N and impart crackability by decarburization or denitrification annealing in wet hydrogen. It is.

Next, the present invention will be explained using Examples and in comparison with Comparative Examples.

Example 1 Steel having the composition shown in Table 1 was melted in a vacuum furnace to form a steel ingot with a thickness and width of about 200 mrn and a length of 400 mm.

This was then hot forged at 950 to 1250°C to form a slab with a thickness of 50 mm, a width of 200 mm, and a length of 80 mm.

Thereafter, this was heated in a heating furnace at 1150°C for 1 hour, and rolling was immediately started, with a final finishing temperature of 840°C.
After hot rolling to a finished plate thickness of 3 mm, it was immediately milled below 400°C and cooled.

First, at this stage, the presence or absence of cracks at the edges of the hot rolled sheet was observed.

In addition, a test piece with a thickness of 1.0 mm, a width of 10 mm, and a length of 120 mm was taken from the hot-rolled plate, and (a) as it was taken, (b) immediately after being subjected to 2% tension processing or rolling processing, and
- The magnitude of internal friction Q-1 was measured for each of the pieces left at room temperature for one month.

Measurement of internal friction was carried out at a temperature of 23°C and at a frequency of approximately 28°C.
The test was conducted at 0 Hz using a capacitive drive type.

Note that the maximum strain amplitude at this time was in the range of 0.1 to 1×10 −5 .

As is clear from the observation results shown in Table 1, cracks in hot rolled sheets occur when Mn/S is 5.1 or less in Ti-free steel, but Mn/S is as low as 3.2 in Ti-added steel. It has not occurred in anything.

In addition, Fig. 1 shows sample //61 (general Al-killed steel),
Regarding sample A:5 (S-added steel), sample A67 ('l'i-added steel), and sample Al l (TiS-added steel), the magnitude of internal friction due to tensile processing and room temperature aging Q-
1, and it can be seen that sample washing 7 shows the maximum value when taken as is, but Q-1 hardly increases even after cold working.

In addition, in sample A6.5, Q-1 increases due to processing, but Q-1 becomes thick (decreased) due to aging for one month at room temperature.

On the other hand, with the steel of the present invention, the Q-1 value as obtained is not high, but by cold working, the Q-1 value is not high.
It is clear from FIG. 1 that this value increases rapidly and does not decrease even with aging.

FIG. 2 relates to Ti-added steels of samples //67 to 13, and shows the change in Q-1 depending on the S content.

The internal friction Q-1 is not large when collected as is, but it is 2
% by tensile or rolling processing, and did not decrease even after aging, and this Q
It can be seen that the increase in is greater in tensile processing.

As described above, the steel sheet of the present invention has a high vibration damping ability and is effective in reducing noise if the user performs forming processing after hot rolling or if it is temper rolled before shipping. That is clear.

Example 2 Steel with the same composition as Samples A6.1 to 13 shown in Table 1 was
A slab was prepared in the same manner as in Example 1, and then 125
After heat treatment at 0° C. or 1150° C. for 1 hour, a hot rolled sheet was prepared in the same manner as in Example 1.

Next, this was pickled, cold rolled to a thickness of 1.0 mm, and then recrystallized annealed at 700° C. for 5 hours.

Furthermore, this was subjected to 1% temper rolling.

From the cold-rolled steel sheet obtained in this way, with the same dimensions as in Example 1, (a) internal friction of the sample as-is (1% temper rolling and then left for more than 1 month). Q-1
Measurement, (b) Tensile test in the direction perpendicular to rolling (T direction) (JI
A conical cup test was conducted using a blank of 5Qm71Lφ.

It goes without saying that the larger the elongation in the tensile test and the smaller the conical cup value, the better the workability.

These results are shown in FIGS. 3 and 4.

First, as shown in Figure 3, the value of internal friction Q -1 is
When S > 0.038% and Ti was contained, the value was 2 x 10-3 or more, a very favorable value. On the other hand, ordinary carbon steel contains a large amount of S. However, Q-1 only showed a value of 2.XIO'' or less.

Furthermore, the results showed that Q-1 is larger when the hot-rolled slab heating temperature is 1150°C than when it is 1250°C.

Furthermore, as shown in FIG. 4, the processability tends to decrease as the amount of S increases, but it is clear that the amount of decrease is small when F゛Ti is added.

However, it can be seen that at 0.25% or more S, the elongation in the T direction decreases significantly even in Ti-added steel.

As described above, it can be seen that although the slab heating temperature does not have much influence on the workability of the material, it is better to limit the slab heating temperature to the range of the present invention in terms of the allocation property.

Example 3 Steel having the components shown in Table 2 was melted in a vacuum furnace to produce a 1O steel ingot with a thickness and width of about 200 mm and a length of 400 m1.

Next, this is hot forged at 950-1150℃,
Thickness 50mm, width 200mm.

Then, it was made into a slab with a length of 800 mm.

After heating this in a heating furnace at 1150° C. for 1 hour, rolling was immediately started, and the sheet was hot-rolled to a final finishing temperature of 840° C. and a finished plate thickness of 3 mm, followed by air cooling.

Next, these hot-rolled steel sheets were pickled, cold-rolled to a thickness of 1, 0, and further recrystallized annealed at 700° C. for 5 hours.

Thereafter, it was cooled to room temperature and then subjected to 1.0% temper rolling.

The internal friction was measured under the same conditions as in Example 1,
Both the hot-rolled sheet and cold-rolled steel sheet are subjected to 2% tensile processing,
Thereafter, each sample was left at room temperature for one month or more to age and then measured.

The results are shown in Table 2.

As is clear from Table 2, the internal friction Q-1 of samples 101.122 and 123, where the Ti equivalent is less than 0, has a small value of 1.0×10” or less for both hot-rolled sheets and cold-rolled sheets. Indicated.

In addition, sample A 121, in which the S content was less than 0.038%, exhibited a Q-1 value of 3 to 1.7×10”, which was smaller than the steel sheet of the present invention.

On the other hand, those with a Ti equivalent of more than 0 and an S content of more than 0.038% have 3.8 to 6.0 10-
It shows a large Q-1 value of 3, and it is clear that it is excellent as a vibration damping steel sheet material.

Example 4 Slabs having the components shown in Table 3 were produced by converter treatment, vacuum treatment, and continuous casting.

The slab dimensions were 230 mm thick and 1230 mm wide.

After heating this in a heating furnace to 1160℃, the final finishing temperature is 8
It was hot-rolled at 80°C to a finished size of 3.2 mm, and wound up at 620°C.

This was then pickled and used as a hot rolled sheet sample.

For comparison, a general low-carbon hot-rolled steel plate of the same thickness was also prepared.

For these prepared samples? Table 4 shows the JIS No. 5 tensile test results and crystal grain waste, and the internal friction after 2% tensile processing was performed in the same manner as in Example 1 and left at room temperature for one month. The value of Q-1 is also the fourth
Shown in the table.

As is clear from the results shown in Table 4, there is no major difference in the tensile test values and grain size, but the value of Q-1 is significantly larger for the steel sheet of the present invention than for the comparison steel sheet. .

Example 5 A hot rolled sheet similar to Example 4 was pickled and then cold rolled to LOmm thickness (reduction ratio: 68.8%), box annealed at 730°C for 4 hours, or box annealed at 750°C for 30 seconds. Continuous annealing was performed.

Next, each sample was subjected to about 0.5% temper rolling at room temperature, and after being left at room temperature for one month, the following tests were conducted.

First, a tensile test and grain size measurement were carried out in the same manner as in the case of the hot-rolled sheet in Example 4, and in addition, a conical cup test and an Erichsen test were carried out.

Internal friction Q-1 was measured (a) as-collected, and (b) after 2% tensile processing and after being left at room temperature for one day.

Further, cylindrical drawing was performed on a 33φ blank rather than a 66φ blank with a drawing ratio of 2, and the blank was hung with a thread and struck with a constant force with a hammer to evaluate the loudness of the impact sound.

This was carried out both immediately after molding and after being left at room temperature for one day after molding.

Table 5 shows the results. As is clear from the results shown in Table 5, there were no major differences between the inventive steel sheet and the comparison steel sheet in terms of mechanical test values and grain size; The impact sound was significantly larger than that of the comparison steel sheet, and the steel sheet of the present invention had a smaller impact sound, indicating that the steel sheet of the present invention has an extremely excellent distribution ability.

It has also been found that the effect of the steel sheet of the present invention is not reduced even if the surface is plated.

As described above, the present invention provides a steel plate that is similar to or better than conventional general steel plates in terms of mechanical properties and formability, and has significantly superior vibration damping ability after aging at room temperature. This brings about industrially useful effects, such as making it possible to take extremely effective measures to reduce noise and vibration from machines, equipment, etc.

[Brief explanation of drawings]

Figure 1 shows general A1 killed steel, S-added steel, Ti-added steel,
A diagram showing the change in internal friction Q-1 when subjected to tensile processing and room temperature aging for Ti-8 composite additive steel. Figure 2 shows the change in Q-1 due to S content for Ti-added steel. FIG. 3 is a diagram showing the relationship between S content and Q-1 in Ti-added steel and ordinary carbon steel, and FIG.
FIG. 2 is a diagram showing the relationship between S content, T-direction elongation, and conical cup value in i-added steel and ordinary carbon steel.

Claims (1)

[Claims] 1% by weight, C: 0.002-0.080%, Mn
:0.05~3,00%, S:0.038~0.250
%, Sol, Al: 0.20% or less, N: 0.020
% or less, and further contains 1.0% or less of Ti, 1.
Contains one or more of 0% or less Nb, 1.0% or less Ta, and 1.0% or less Zr, and the total amount thereof satisfies the formula: A vibration-damping steel plate for processing, characterized in that it has a composition consisting of: Fe and unavoidable impurities: the remainder. 2% by weight, C: 0.002-0.080%, Mn:
0.05-3.00%, S: 0.038-0.250%
, Sol, Al: 0.20% or less, N: 0.020%
Containing the following, further comprising 1.0% or less of Ti; 1.
Contains one or more of 0% or less Nb, 1.0% or less Ta, and 1.0% or less Zr1, and the total amount thereof satisfies the formula: A vibration-damping steel plate for processing, characterized in that it further contains 3% or less of Si, and has a composition consisting of: Fe and unavoidable impurities: the remainder. 3% by weight, C: 0.002-0.080%, Mn
:0.05~3.00%, S:0.038~0.250
%, Sol, AI: 0.20% or less, N: 0.020
% or less, and further contains 1.0% or less of Ti, 1.
Contains one or more of 0% or less Nb, 1.0% or less Ta, and 1.0% or less Zr, and the total amount thereof satisfies the formula: Fe and unavoidable impurities: After melting steel having a composition consisting of the following in a converter etc., continuous casting is performed to form a slab, and then this slab is
A method for producing a damping steel plate for processing, which comprises heating to 50 to 1180°C and then hot rolling. 4% by weight, C: 0.002-0.080%, Mn
:0.05~3.00%, S:0.038~0.250
%, Sol, Al: 0.20% or less, N: 0.0
20% or less, and further contains 1.0% or less of Ti,
1.0% or less Nb, 1.0% or less Ta, 1.0%
A steel containing one or more of the following Zr, the total amount of which satisfies the formula: Fe and unavoidable impurities: the remainder, and having a composition consisting of: After melting, it is made into a slab by continuous casting, and then this slab is
A steel plate obtained by hot rolling after heating to 50 to 1180°C,
After pickling and cold rolling at a rolling reduction of 20% or more,
A method for manufacturing a damping steel plate for processing, which is characterized by annealing.