JP5303908B2 - Member having excellent damping ability, method for producing the same, and steel sheet used as member having excellent damping ability - Google Patents

Description

  The present invention relates to a member having excellent damping ability, such as home appliances and automobile parts, such as oil pans, in which noise and vibration during use are desired and low noise and vibration are desired, and a method for manufacturing the same, and The present invention relates to a steel plate suitable for a member having excellent damping ability.

  2. Description of the Related Art With increasing social needs for reducing noise and vibration for automobile parts such as oil pans and home appliances, there has been a growing demand for low noise members and low vibration members. For example, for so-called low-noise members where noise such as oil pans for automobiles is a problem, a resin composite type damping metal having a viscoelastic resin interposed between two metal plates as described in Patent Document 1 The use of plates is under consideration. However, the use of such resin composite vibration-damping metal plates, etc., is due to high manufacturing costs, poor workability, and poor weldability, so that the parts themselves have excellent low noise performance and vibration reduction performance. Is desired. In order to reduce the noise and vibration of the member itself, it is common to increase the sound insulation performance and increase the rigidity by increasing the plate thickness, but the material cost will increase and the weight of the member will increase. .

Therefore, a steel plate that is less expensive than a resin composite vibration-damping metal plate or the like is used as the member material, and the damping of the vibration of the steel plate itself that constitutes the member is increased, that is, the member is configured using a steel plate having excellent damping capacity. Therefore, it is desired to increase the damping capacity of the member. Here, as a steel plate having excellent damping ability, a ferromagnetic-type damping steel plate using hysteresis of domain wall movement, for example, Patent Documents 2 to 4, include at least one of ferrite former elements such as Al, Si, and Cr. A high alloy steel sheet to which 1% or more of seed elements are added has been proposed. In such a steel sheet, vibration energy is lost by converting it into energy of domain wall motion, so that vibration is attenuated and noise is reduced.
Japanese Patent Laid-Open No. 10-86271 JP-A-4-99148 JP 52-73118 A JP 2002-294408 A

  However, the high alloy steel sheets described in Patent Documents 2 to 4 are hard, inferior in workability, and unsuitable for members such as oil pans manufactured by deep drawing.

  The present invention has been made in view of such circumstances, and a member excellent in damping ability that can reduce noise and reduce vibration using a steel plate that is easy to process, a method for manufacturing the same, and a member that has excellent damping ability. It aims at providing a suitable steel plate.

  As a result of intensive research on damping performance such as noise performance after processing of the steel sheet, the present inventors made the average crystal grain size of the steel sheet 30 μm or more after processing, and set the Vickers hardness of the hardest part after processing to 120 μm. It has been found that excellent damping performance can be obtained if the following is used.

The present invention has been made based on such findings,
(1) In a member manufactured by processing a steel plate, a member having an excellent damping ability is characterized in that the average crystal grain size of the steel plate is 30 μm or more, and the Vickers hardness of the hardest part is 120 or less. .
(2) If the average crystal grain size of the steel sheet is 50 μm or more, more excellent damping performance can be provided.
As a steel plate, for example,
(3) By mass%, C: 0.050% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 1.0% or less, N: 0.005% or less It is preferable to use a steel plate having a composition comprising the balance Fe and inevitable impurities.
(4) It is preferable that the steel sheet of (3) further contains B: 0.0001 to 0.0030% by mass%.

further,
(5) By mass%, C: 0.005% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 1.0% or less, N: 0.005% or less, Steel sheet containing Ti: 0.01-0.06%, B: 0.0001-0.0030%, having a composition consisting of the balance Fe and inevitable impurities,
Or
(6) By mass%, C: 0.005% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 0.004% or less, N: 0.005% or less It is preferable to use a steel plate having a composition comprising the balance Fe and inevitable impurities.

In the steel sheet, the crystal grain size can be 30 μm or more by heat treatment performed after processing into a desired shape, but the average grain size as a steel sheet before processing into a desired shape is 30 μm in advance. As described above, it is more preferable that the thickness is 50 μm or more, and it is preferable to use it as a member having excellent damping ability by heat treatment in a temperature range of 500 ° C. or higher after processing into a desired shape.
That is,
(7) By mass%, C: 0.050% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 1.0% or less, N: 0.005% or less Contained, steel sheet with the balance of Fe and unavoidable impurities, with an average crystal grain size of 30μm or more, and after processing to a desired shape, heat treatment in a temperature range of 500 ° C or higher has excellent damping capacity Steel plate, characterized in that it is used as a member
(8) A steel plate further containing, in mass%, B: 0.0001 to 0.0030% in the steel plate of (7),
Or
(9) By mass%, C: 0.005% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 1.0% or less, N: 0.005% or less, Ti: 0.01% to 0.06%, B: 0.0001% to 0.0030%, a steel plate having a composition composed of the balance Fe and inevitable impurities, and having an average particle size of 30 μm or more, and after processing into a desired shape, 500 It is a steel plate characterized by being used as a member excellent in damping capacity by heat treatment in a temperature range of not lower than ° C.

In the steel plates of (7) to (9) above,
(10) It is more preferable that the average crystal grain size is 50 μm or more.

The member excellent in damping capacity of the present invention is, for example,
(11) The steel plates of (7) to (10) described above can be produced by heat treatment in a temperature range of 500 ° C. or higher after processing into a desired shape.

Further, in the steel sheet having the component composition described in (7) above, when the amount of C and Al is reduced and excellent crystal grain growth is ensured, the heat treatment temperature applied after processing is set to 600 ° C. or higher. It is easy to secure an average crystal grain size of 30 μm or more in the heat treatment performed after processing. That is, when the heat treatment temperature to be applied after processing is set to 600 ° C. or higher, it is preferable to use the following steel plate (12).
(12) By mass%, C: 0.005% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 0.004% or less, N: 0.005% or less A steel sheet comprising: a composition comprising balance Fe and unavoidable impurities, wherein the steel sheet is heat-treated in a temperature range of 600 ° C. or higher after processing into a desired shape, and used as a member having excellent damping ability.

The member excellent in damping capacity of the present invention is, for example,
(13) The steel plate of (12) described above can be produced by heat treatment in a temperature range of 600 ° C. or higher after processing into a desired shape.

  According to the present invention, it has become possible to provide a member (hereinafter referred to as a high attenuation member) having excellent damping ability such as a low noise member suitable for an oil pan or the like. Further, the high damping member of the present invention can be applied to members other than oil pans that are severely processed in fields such as automobiles and home appliances and that require low noise performance and vibration reduction performance (damping performance).

  The point of the present invention is that, in a high damping member manufactured by processing a steel plate by press working or the like, the average grain size of the steel plate in a state manufactured in the member is set to 30 μm or more and the grain boundary is reduced and the hardest The Vickers hardness of the part is set to 120 or less to reduce residual stress and distortion in the crystal grains, to facilitate the domain wall movement in the steel sheet, and to convert the vibration energy into the domain wall movement energy, thereby reducing the vibration damping ability of the steel sheet. It has a high attenuation performance such as an improved low noise performance.

  When the average crystal grain size is less than 30 μm, there are many crystal grain boundaries that hinder domain wall movement, and thus excellent high damping performance cannot be obtained.

  On the other hand, if the Vickers hardness of the hardest part exceeds 120, the dislocation density in the crystal grains that hinders domain wall movement increases, so that excellent high damping performance cannot be obtained.

  As the steel sheet used in the present invention, a hot rolled steel sheet, a cold rolled steel sheet, or the like can be used. For example, JIS G 3131 SPHD or SPHE grade hot-rolled steel sheet or JIS G 3141 SPCD or SPCE grade cold-rolled steel sheet, which has been conventionally used for members that require severe deep drawing, can be used. In particular, in mass%, C: 0.050% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 1.0% or less, N: 0.005% or less A steel sheet is preferred for the following reasons.

  Since C: C forms carbides and inhibits grain growth, it cannot reduce grain boundaries that hinder domain wall movement. Therefore, the C content is 0.050 mass% or less. From the viewpoint of improving workability, the C content is preferably 0.005% by mass or less.

  Si: Si is a solid solution strengthening element, but excessive addition inhibits manufacturability and workability. Therefore, the Si content is less than 1.0% by mass. More preferably, it is 0.5 mass% or less, More preferably, it is 0.3 mass% or less.

  Mn: Mn is an element that forms sulfides and improves hot brittleness, and is a solid solution strengthening element. Therefore, the Mn content is preferably 0.05% by mass or more. On the other hand, if added in a large amount, the workability deteriorates and the cost increases. Therefore, the upper limit of the Mn amount is 0.5% by mass.

  P: P is a solid solution strengthening element, but if its amount exceeds 0.04% by mass, the workability deteriorates. Therefore, the upper limit of the P content is 0.04% by mass.

  If the S: S content exceeds 0.03% by mass, sulfides are formed and the grain growth is significantly hindered. Therefore, the amount of S is 0.03% by mass or less, preferably 0.01% by mass or less, more preferably 0.005% by mass or less, and still more preferably less than 0.003% by mass.

  Al: Al is a deoxidizing element, but excessive addition inhibits manufacturability and causes an increase in cost. Therefore, the Al content is preferably 1.0% by mass or less. Further, since it is an element that forms AlN and significantly inhibits grain growth, the Al content is more preferably 0.004% by mass or less.

  When the N: N amount exceeds 0.005 mass%, precipitates are formed and hinder grain growth. Therefore, the N content is 0.005% by mass or less, preferably 0.003% by mass or less.

  The balance other than the above elements is preferably Fe and inevitable impurities. In order to improve the aging property by reducing the solid solution N, 0.0001 to 0.0030 mass% of B may be further added. This is because if the amount of B is less than 0.0001% by mass, the effect of improving the aging resistance is small, and if it exceeds 0.0030% by mass, the castability deteriorates and the manufacturing cost increases. Further, from the viewpoint of further improving the deep drawability by fixing C and N as precipitates, the C amount is 0.005 mass% or less, and the Si, Mn, P, S, Al, N amount as the above range, Furthermore, while adding 0.01 to 0.06 mass% of Ti, 0.0001 to 0.0030 mass% of B may be added from the viewpoint of improving secondary work brittleness. This is because when the Ti content is less than 0.01% by mass, the soft and slow aging property is insufficient, and when the Ti content exceeds 0.06% by mass, the cost increases. When the B content is less than 0.0001% by mass, This is because the next processing brittleness is not sufficient, and if the B content exceeds 0.0030 mass%, the castability deteriorates and the cost increases.

  The high damping member of the present invention can be produced by processing a steel sheet satisfying the above-mentioned standards and composition into a desired shape and then heat-treating it in a temperature range of 500 ° C. or higher. This heat treatment is considered to be due to the fact that grain growth occurs and grain boundaries are reduced, residual stress and strain in the crystal grains are reduced, and domain wall movement is facilitated.

  As the steel sheet used in the present invention, the average crystal grain size is set to 30 μm in advance, that is, as the steel sheet before being processed into a desired shape, regardless of the heat treatment conditions after processing, the average crystal grain size is 30 μm or more. Can be ensured.

  Also, by reducing the amount of C and Al, specifically, as described above, C ≦ 0.005 mass%, Al ≦ 0.004 mass% to ensure excellent crystal grain growth, after processing into the desired shape It is preferable that the heat treatment to be performed is 600 ° C. or higher because the average crystal grain size can be 30 μm or more, or even 50 μm or more in the heat treatment stage. That is, in mass%, C: 0.005% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 0.004% or less, N: 0.005% or less In addition, it is preferable to have a composition composed of the remaining Fe and inevitable impurities and heat-treat in a temperature range of 600 ° C. or higher after processing into a desired shape to obtain a high attenuation member.

  In the above, since the energy cost is remarkably increased when the temperature of the heat treatment performed after processing into a desired shape exceeds 910 ° C., the heat treatment is desirably performed at 910 ° C. or less. In the present invention, brittleness can be improved by heat treatment after processing. However, since excessive coarsening may cause brittleness problems, the average crystal grain size is preferably 2000 μm or less.

  The method for manufacturing a high damping member according to the present invention is particularly effective for a member manufactured by deep drawing or bending. From the viewpoint of production cost, the steel sheet to be used is preferably a hot rolled steel sheet having a thickness of about 1.6 to 6.0 mm.

  Here, an example of the manufacturing method of the hot-rolled steel plate used for this invention is shown. In addition, the manufacturing method of this hot-rolled steel plate is not limited to this illustration. That is, the hot-rolled steel sheet used in the present invention is a steel having the above components heated at a heating temperature of less than 1200 ° C, hot-rolled at a finishing temperature of 700 ° C or higher, and wound at a winding temperature of 560 ° C or higher. It is manufactured by removing the scale by picking and pickling. If the heating temperature is less than 1000 ° C, it will be difficult to secure a finishing temperature of 700 ° C or higher. If the heating temperature is 1200 ° C or higher, trace impurities will form a solid solution and precipitate finely during winding to inhibit grain growth during heat treatment. Therefore, the heating temperature is preferably 1000 ° C. or higher and lower than 1200 ° C. More preferably, it is 1000 ° C. or higher and 1150 ° C. or lower. The reason why the finishing temperature is set to 700 ° C. or more is that the plate shape tends to deteriorate at a lower temperature. The reason why the coiling temperature is set to 560 ° C. or more is that at a temperature lower than that, fine precipitates such as AlN are generated during the heat treatment performed after the processing, and the grain growth is easily inhibited.

  In addition, the hot-rolled steel sheet after the above winding or after further scale removal is to further increase the crystal of the hot-rolled steel sheet to an average crystal grain size of 30 μm or more, or even 50 μm or more. It is preferable to perform annealing. This is because if the annealing temperature in the annealing is less than 650 ° C., the effect on the grain growth is small, and if it exceeds 900 ° C., the effect tends to be saturated, which only increases the cost. By controlling the annealing temperature in the annealing, it is easy to set the average crystal grain size of the hot-rolled sheet to a desired value. Here, it is preferable to remove the scale by pickling after the annealing. In addition, when the atmosphere is adjusted to a non-oxidizing atmosphere using the hot-rolled steel sheet after removing the scale and annealing is performed under conditions that do not cause a problem of scale generation, pickling after annealing can be omitted.

  Further, when the thickness is less than 1.6 mm, which is difficult to manufacture by hot rolling, or particularly when the surface is required to be beautiful, it is preferable to use a cold-rolled steel sheet, although the manufacturing cost increases. Although the cold-rolled steel sheet used in the present invention is not particularly limited, the hot-rolled steel sheet having the above components and manufactured by the above manufacturing method is used as a base material, and rolled at a cold rolling rate of 80% or less. And it can manufacture by annealing at the annealing temperature of 800 degreeC or more. Here, the cold rolling rate is set to 80% or less and the annealing temperature is set to 800 ° C. or less. When the cold rolling rate exceeds 80% or the annealing temperature is less than 800 ° C., a fine grain structure is formed after annealing. This is because it is difficult to obtain a particle size of 30 μm or more after the heat treatment performed after the processing. In addition, what is necessary is just to set a cold rolling rate suitably according to desired plate | board thickness in the range of 80% or less. In addition, if the annealing temperature exceeds 900 ° C., it tends to be difficult to manufacture and the manufacturing cost is extremely increased.

  Since the high attenuation member of the present invention is manufactured by simply heat-treating a steel plate, it can be welded to other members or baked without any problems.

  Steel slabs having components within the scope of the present invention shown in Table 1 are reheated to a heating temperature of 1100 ° C, hot-rolled at a finishing temperature of 930 ° C, wound up at a winding temperature of 600 ° C, and pickled A hot rolled steel sheet equivalent to SPHE with a thickness of 3.6 mm was manufactured. Further, a part of the obtained hot-rolled steel sheet was subjected to hot-rolled sheet annealing at 700 ° C. for 1 hour. In addition, the structure was observed in the thickness direction cross section in the rolling direction of the as-rolled steel sheet not subjected to hot-rolled sheet annealing and the steel sheet after hot-rolled sheet annealing, and the average crystal grain size was determined by the cutting method described in JIS G 0551. The average crystal grain size of the hot-rolled steel sheet was 25 μm, and the average crystal grain size of the steel sheet after hot-rolled sheet annealing was 43 μm.

And in order to simulate the processing conditions as a high damping member (low noise member in this example), a 66 mmφ disc was punched from the hot rolled steel plate and the hot rolled steel plate, and a 33 mmφ flat bottom punch was used. Drawing was performed (drawing ratio: 2), and cup-shaped samples No. 1 to 9 were produced. Then, the cup-shaped samples No. 1 to 9 were heat-treated under the conditions shown in Table 2, and based on JIS A 1409, the cup-shaped samples were within the range of 2.0 to 2.5 Nrms with an impact hammer (PCB PIEZOTRONICS, model number 086B01). The reverberation time T ₆₀ when struck with an excitation force was measured, and the loss factor η was calculated from the following equation based on the attenuation rate method.
η = 2.2 / (T ₆₀・ f ₀ )
Here, f ₀ is the natural frequency of the cup-shaped sample and is 3.5 kHz.

  In addition, the cup-shaped sample after the reverberation time measurement was cut so as to be plane symmetric in the cup height direction (drawing direction), and about one half of the cut sample, which is symmetric in the cup height direction, Observation of the structure of the cut surface and measurement of Vickers hardness at a test force of 4.9 N (500 g) were carried out in the direction of the cup edge at equal intervals from the top of the cup at a pitch of 10 mm. Of the measured locations (5 locations), the portion with the highest hardness was defined as the Vickers hardness of the hardest portion of the cup-shaped sample. The average of the crystal grain sizes at these five observed positions was obtained and used as the average crystal grain size of the cup-shaped sample.

  The results are shown in Table 2. Samples Nos. 4, 5, and 8 and 9 heat-treated by the method of the present invention have an average crystal grain size of 30 μm or more, a Vickers hardness of 120 or less, a loss factor η of 0.001 or more, a high damping capacity, and a low noise It turns out that it is excellent in performance. In particular, it can be seen that Samples Nos. 5 and 9 having an average crystal grain size of 50 μm or more have a higher loss factor η and have a higher noise reduction performance and a lower noise performance.

  The steel slab having the chemical composition shown in Table 3 was reheated to a heating temperature of 1100 ° C, hot-rolled at a finishing temperature of 910 ° C, wound up at a winding temperature of 700 ° C, pickled and washed to a thickness of 3.2. mm hot rolled steel sheet was produced. A part of the obtained hot-rolled steel sheet was subjected to hot-rolled sheet annealing at 800 ° C. for 2 hours. And like Example 1, the sample processed into a cup-shaped sample and not subjected to hot-rolled sheet annealing was subjected to heat treatment at 850 ° C. for 3 hours, and the sample subjected to hot-rolled sheet annealing was subjected to 500 ° C. for 3 hours. The sample Nos. 10 to 17 were prepared by performing the heat treatment, and the average crystal grain size, Vickers hardness, and loss factor η were measured. Note that the average crystal grain size of the hot-rolled steel sheet before processing was determined in the same manner as in Example 1.

The results are shown in Table 3 . In the case of using the specimen No.10~15 and 18 to 21, it can be seen that the loss factor η is high, and low noise can be realized with a high damping capacity. On the other hand, sample Nos. 16 and 17 to which 5.6% Al was added in order to improve vibration damping had only 30% and 31% elongation of the hot-rolled steel sheet, respectively. It was not possible to process the sample.

The Ca-up like sample No.1 and mosquito-up like sample No.4 prepared in Example 1, Paste a strain gauge on the inside (the position of 5mm from the cup edge) of the cup, as shown in FIG. 1 The impact force (PCB PIEZOTRONICS, model number 086B01) was used to change the excitation force, hit the outside of the cup and vibrate, and the maximum amount of strain at each excitation force was measured.

The results are shown in Table 4 and FIG . Ca-up like sample No.4, compared to mosquito-up like sample No.1, be tapped excitation force comparable small maximum distortion amount found to have excellent low vibration characteristics.

  Steel slab having the chemical composition shown in Table 5 is reheated to a temperature of 1100 ° C, hot-rolled at a finishing temperature of 910 ° C, wound up at a winding temperature of 700 ° C, pickled and washed with a thickness of 3.6 mm The hot rolled steel sheet was manufactured. The hot-rolled steel sheet was cold-rolled to 1.0 mm, annealed at 700 ° C or 850 ° C for 1 minute, and temper rolled at 1%. From this cold-rolled steel sheet, it was processed into a cup-shaped sample in the same manner as in Example 1, and subjected to a heat treatment at 500 ° C. for 3 hours to prepare Sample No. 22 and 23, and the average crystal grain size, Vickers hardness and loss factor η Was measured. For the cold rolled steel sheet before processing, the average crystal grain size was determined in the same manner as in Example 1.

  The results are shown in Table 5. No. 23, which is an example of the present invention, has a high loss coefficient and a high damping capacity, but No. 22 having a low annealing temperature and a small crystal grain size has a low loss coefficient.

It is a figure which shows the cup-shaped sample which affixed the strain gauge. It is a figure which shows the relationship between an exciting force and the largest distortion amount.

Claims (7)

In mass%, C: 0.050% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 1.0% or less, N: 0.005% or less, B: 0.0001 In a member manufactured by heat-treating a steel plate having a composition comprising ~ 0.0030% and the balance Fe and inevitable impurities , the average crystal grain size of the steel plate is 30 μm or more and the Vickers hardness of the hardest part is A member excellent in damping ability having a loss coefficient η of 0.001 or more, characterized by being 120 or less. In mass%, C: 0.005% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 1.0% or less, N: 0.005% or less, Ti: 0.01 In a member produced by processing a steel sheet having a composition comprising -0.06%, B: 0.0001-0.0030%, the balance Fe and inevitable impurities , and heat-treated , the average grain size of the steel sheet is 30 μm or more, A member excellent in damping ability having a loss coefficient η of 0.001 or more, characterized in that the Vickers hardness of the hardest part is 120 or less. 3. The member having excellent damping capacity according to claim 1, wherein the steel sheet has an average crystal grain size of 50 μm or more. In mass%, C: 0.050% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 1.0% or less, N: 0.005% or less , B: 0.0001 It is a steel sheet containing ~ 0.0030% , having a composition composed of the balance Fe and inevitable impurities, and having an average crystal grain size of 30 μm or more, and heat-treated in a temperature range of 500 ° C. or more after processing into a desired shape A steel sheet characterized by being used as a member excellent in damping capacity having a loss coefficient η of 0.001 or more . In mass%, C: 0.005% or less, Si: less than 1.0%, Mn: 0.05 to 0.5%, P: 0.04% or less, S: 0.03% or less, Al: 1.0% or less, N: 0.005% or less, Ti: 0.01 -0.06%, B: 0.0001-0.0030%, having a composition composed of the balance Fe and inevitable impurities, and having an average crystal grain size of 30 μm or more, 500 ° C. or higher after processing into a desired shape A steel sheet characterized by being used as a member excellent in damping ability having a loss coefficient η of 0.001 or more when heat-treated in the above temperature range. 6. The steel sheet according to claim 4, wherein the average crystal grain size is 50 μm or more. A steel sheet according to any one of claims 4 to 6 , after being processed into a desired shape, heat-treated in a temperature range of 500 ° C or higher, a member having an excellent damping ability having a loss coefficient η of 0.001 or higher Production method.