JP2786568B2 - Structural members and their manufacturing methods - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hydrofoil of a high-speed passenger boat, offshore oil-related equipment, and other structural members which require high strength, high toughness and high corrosion resistance and require welding.

[0002]

2. Description of the Related Art Conventionally, the heat treatment of the above-mentioned structural member is usually performed by quenching and tempering, and after welding, a re-solution treatment and an aging treatment are performed.

[0003]

However, when the above-mentioned re-solution treatment is performed, the welded structural member is deformed by the residual stress or its own weight during the heat treatment. Restraint is required.
Further, even a structural member which does not include welding has much lower toughness as compared with a member provided with the heat treatment method of the present invention.

[0004] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a structural member capable of preventing deformation during heat treatment and significantly improving toughness, and a method of manufacturing the same.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present invention has prevented a deformation during heat treatment and further improved toughness, and a new structural member and a method of manufacturing the same. Was invented. That is,

(1) Carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to
5%, nickel: 3 to 5.5%, chromium: 14 to 17.
5%, molybdenum: 0.5% or less, niobium: 0.15-
0.45% and a balance substantially composed of iron, and an ε phase is precipitated in a matrix composed of an austenite phase of 6 to 30% by volume and a balance substantially composed of a martensite phase. Structural member with high toughness and small heat distortion.

(2) A hull, a propulsion device provided at the rear of the nuclear hull, and provided substantially below the hull in a horizontal direction, with a weight ratio of carbon: 0.07% or less, silicon: 1%
Hereafter, manganese: 1% or less, copper: 2.5 to 5%, nickel: 3 to 5.5%, chromium: 14 to 17.5%, molybdenum: 0.5% or less, niobium: 0.15 to 0 Stainless steel having a composition of .45% and a balance substantially composed of iron, and having a structure in which an ε phase is precipitated in a matrix including an austenite phase of 6 to 30% by volume and a balance substantially composed of a martensite phase. A ship equipped with a hydrofoil composed of:

(3) Carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to
5%, nickel: 3 to 5.5%, chromium: 14 to 17.
5%, molybdenum: 0.5% or less, niobium: 0.15-
A structure in which a first solution treatment is performed at 1010 to 1050 ° C on stainless steel of 0.45% and the balance substantially consisting of iron, and then the first aging treatment is performed at 520 ° C to 630 ° C. A method for manufacturing a structural member, further comprising performing a second solution treatment at 730 to 840 ° C. and then performing a second aging treatment at a temperature of 520 ° C. to 630 ° C. in the member manufacturing method.

(4) Carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to
5%, nickel: 3 to 5.5%, chromium: 14 to 17.
5%, molybdenum: 0.5% or less, niobium: 0.15-
A structure in which a first solution treatment is performed at 1010 to 1050 ° C on stainless steel of 0.45% and the balance substantially consisting of iron, and then the first aging treatment is performed at 520 ° C to 630 ° C. In the method of manufacturing a member, a structural member having an arbitrary shape is formed by welding, and then the second solution treatment is carried out in 7
After performing at 30 to 840 ° C, the second aging treatment is performed at 520 ° C.
A method for producing a structural member, which is performed at a temperature of 630 ° C. or lower.

(5) Carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to
5%, nickel: 3 to 5.5%, chromium: 14 to 17
%, Molybdenum: 0.5% or less, niobium: 0.15-
After performing a first solution treatment at 1010 to 1050 ° C. on stainless steel of 0.45% and the balance substantially consisting of iron, a first aging treatment is performed at 520 ° C. to 630 ° C. The temperature is raised at a rate of not more than ℃ / hour, a second solution treatment is performed at 730-840 ° C., and then cooled to room temperature at a cooling rate of not more than 100 ° C./hour in a furnace;
A method for producing a structural member, further comprising performing a second aging treatment at a temperature of 520 ° C. or more and 630 ° C. or less, and thereafter cooling to room temperature in a furnace at a cooling rate of 100 ° C./hour or less.

(6) Carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to
5%, nickel: 3 to 5.5%, chromium: 14 to 17.
5%, molybdenum: 0.5% or less, niobium: 0.15-
After performing a first solution treatment at 1010 to 1050 ° C. on stainless steel of 0.45% and the balance substantially consisting of iron, the first aging treatment is aged at 520 ° C. to 630 ° C. and welded As a structural member having an arbitrary shape, the temperature is further increased at a rate of 100 ° C./hour or less, a second solution treatment is performed at 730 to 840 ° C.
After cooling to room temperature at a cooling rate of 0 ° C./hour or less, the second
Aging treatment at 520 ° C. or more and 630 ° C. or less, and thereafter cooling to room temperature in a furnace at a cooling rate of 100 ° C./hour or less.

(7) Carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to
5%, nickel: 3 to 5.5%, chromium: 14 to 17.
5%, molybdenum: 0.5% or less, niobium: 0.15-
After performing a first solution treatment at 1010 to 1050 ° C. on stainless steel of 0.45% and the balance substantially composed of iron, the first aging treatment is aged at 520 ° C. to 630 ° C. The material is put in a container made of a plate of the above, and the temperature of the material together with the container is raised at a rate of 100 ° C./hour or less, a second solution treatment is performed at 730 to 840 ° C., and then in a furnace After cooling to room temperature at a cooling rate of 100 ° C./hour or less, the second aging treatment is performed at 520 ° C. to 630 ° C.
A method for producing a structural member, comprising the steps of: performing cooling in a furnace at a cooling rate of 100 ° C./hour or less;

(8) Carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to
5%, nickel: 3 to 5.5%, chromium: 14 to 17.
5%, molybdenum: 0.5% or less, niobium: 0.15-
After performing a first solution treatment at 1010 to 1050 ° C. on stainless steel of 0.45% and the balance substantially consisting of iron, the first aging treatment is aged at 520 ° C. to 630 ° C. and welded The material is put in a container made of a metal plate, and the material is heated together with the container at a rate of 100 ° C./hour or less to perform a second solution treatment. 730-840 ° C., and then cooled in the furnace to room temperature at a cooling rate of 100 ° C./hour or less,
A method for producing a structural member, further comprising performing a second aging treatment at a temperature of 520 ° C. or more and 630 ° C. or less, and thereafter cooling to room temperature in a furnace at a cooling rate of 100 ° C./hour or less.

(9) When the temperature of the raw material reaches 550 ° C. to 620 ° C. in the temperature raising step of the second solution treatment, the temperature is maintained for 30 minutes to 2 hours, and the temperature of each part of the raw material is made uniform. The method for producing a structural material according to any one of (5) to (8), wherein the temperature is raised to a second solution heat treatment temperature after waiting to perform.

(10) In the temperature lowering step of the second solution treatment, when the temperature of the material reaches 300 ° C. to 220 ° C., the temperature is maintained for 30 minutes to 2 hours, and the temperature of each part of the material becomes uniform. The method for producing a structural material according to any one of (5) to (8), wherein the temperature is lowered to room temperature after waiting.

(11) When the temperature of the material reaches 300 ° C. to 220 ° C. in the temperature lowering step of the second solution treatment, the temperature is kept at that temperature for 30 minutes to 2 hours, so that the temperature of each part of the material becomes uniform. The method for producing a structural material according to (9), wherein the temperature is lowered to room temperature after waiting.

[0017]

The present inventors have carefully selected the heat treatment conditions for the precipitation hardening type martensitic stainless steel, which is the object of the present invention, so that there is no deformation during the heat treatment and the welding has excellent material properties that cannot be obtained conventionally. A structural member was obtained. The reasons for limiting the present invention are described below. First,
The alloy composition targeted by the present invention is as follows.

(Carbon): If it exceeds 0.07%, the base martensite hardens and becomes hard and brittle. Therefore, 0.
07% or less.

(Silicon): Silicon is a deoxidizing agent,
It works effectively at 1% or less. If it exceeds 1%, embrittlement is caused, so the content is made 1% or less.

(Manganese): Manganese is also a deoxidizing agent,
It works effectively at 1% or less. If it exceeds 1%, the toughness is reduced, and the martensite of the base is destabilized.
The following is assumed.

(Copper): Copper is finely precipitated during aging as an intermetallic compound to improve the material strength. If the content is less than 2.5%, the effect is not sufficient, and if the content exceeds 5%, the toughness is reduced.

(Nickel): Nickel forms a solid solution with the matrix and forms an intermetallic compound together with copper. If the content of nickel is less than 3%, delta ferrite precipitates in the matrix and lowers toughness and ductility. On the other hand, 5.
If the content exceeds 5%, the residual austenite will be present in the matrix at room temperature, so that sufficient strength cannot be obtained. For this reason, it is set to 3 to 5.5%.

(Chromium): Chromium is an essential element for maintaining corrosion resistance, and is a main element of the present material. 14%
If it is less than this, sufficient corrosion resistance cannot be obtained. In addition, 17.5%
When the content exceeds 0.1%, delta ferrite is precipitated, so that the content is set to 14 to 17.5%.

(Molybdenum): Molybdenum is an element effective for pitting corrosion resistance. However, if the content exceeds 0.5%, embrittlement is caused, so the content is set to 0.5% or less.

(Niobium): Niobium has the effect of reducing the crystal grain size and improving the strength, ductility and toughness. 0.
If it is less than 15%, the effect is not sufficient, and if it exceeds 0.45%, a large amount of carbide is crystallized at the time of solidification, so that ductility and toughness are reduced. Therefore, 0.
15 to 0.45%. The balance is substantially reduced by iron, a basic element of stainless steel.

The structural member of the present invention has the following structure in addition to the above composition.

(Austenite phase): Generated in the martensite phase of the matrix as a reverse-transformed austenite phase. The austenitic phase itself has excellent toughness, thereby improving the toughness of the entire matrix. The toughness can be further improved by a composite effect of making the martensite grains finer by precipitating the particles. If the amount is less than 6% by volume, the toughness is not sufficiently improved, and if it exceeds 30%, the strength of the matrix becomes insufficient. Therefore, the austenite phase is 6 to 30% by volume.
Preferably, the content is 10 to 25% by volume.

(Martensite phase): This is a basic structure constituting the matrix of the member of the present invention, and gives basic properties of the matrix such as mechanical properties.

(Ε phase): Precipitates finely in the matrix of the member of the present invention to strengthen the precipitation of the member of the present invention.

Next, the heat treatment method of the present invention will be described. The first solution heat treatment and the aging treatment are usually heat treatment methods for the material of the present invention, and are JIS standard G4303.
The purpose is the same as that specified in the SUS630 heat treatment method. In this heat treatment, the solute atoms present in the steel are once dissolved in the matrix by solution treatment at 1010 to 1050 ° C., and micro segregation (component bias) is corrected, and then aging at 520 to 630 ° C. A copper-rich intermetallic compound (ε phase) is precipitated to obtain a high-strength material. In the present invention, the second solution treatment and the aging treatment are particularly important points, and these impart high toughness to the material and uniform mechanical properties and high toughness to the weld. In addition, the first
By controlling that the second solution heat treatment temperature is lower than the solution heat treatment temperature and controlling the rate of temperature rise and fall in the heat treatment, the deformation of the material due to the heat treatment can be kept extremely low.

The welding is performed after the first solution treatment and the aging treatment or after the first solution treatment. At this time, the molten metal portion and the heat-affected zone should be originally applied to this material. Since it is a part where no heat treatment is performed (molten metal part) or a part where all the heat treatments performed so far are canceled (heat affected zone), the required strength, toughness, and other various properties are impaired. It is necessary to perform heat treatment again.

Therefore, a second solution treatment is performed. Although this treatment is performed at 730 to 840 ° C., since this treatment can be performed while maintaining the strength of the material as compared with a normal solution treatment, even if this heat treatment is performed particularly on a large welded structural member. In addition, the amount of deformation is smaller than that of the first solution treatment, so that the product can be easily heat-treated. In the heat treatment of the present invention, in order to minimize the amount of deformation during the heat treatment, the solution treatment at a low temperature as described above is employed, and the temperature difference between the respective parts of the material is controlled by controlling the temperature during the heat treatment. And the deformation of the material can be made extremely low. The temperature control method in the present invention will be described later. In addition, the second solution treatment and the second aging can contribute to the material excellent toughness that cannot be obtained by ordinary heat treatment.

The as-welded weld is a heat-affected zone (HAZ)
A softening zone is formed. This is because aging precipitation progresses by being maintained at a high temperature by welding, and overaging softening (precipitation of an intermetallic compound proceeds, precipitates are coarsened and coarsened, and strength is reduced) occurs. In this case, during use, the weak heat-affected zone cracks and breaks earlier than the life of the member. In order to solve such a problem, a re-solution treatment is usually performed.
In this ordinary re-solution treatment, the temperature is the same as the first solution treatment temperature of the present invention. However, in this case, since the temperature is maintained at a high temperature as described above, the residual stress of welding and the stress due to its own weight cause the stress. Deformation occurs, making it difficult to produce a product shape.

In the solution treatment after welding of the present invention, that is, in the second solution treatment, since the solution treatment is performed at a heat treatment temperature considerably lower than the first solution treatment temperature, the first solution treatment is performed. The heat treatment can be performed with a smaller deformation amount than the treatment. In addition, since the solution treatment temperature exceeds the Ac3 transformation point (the temperature at which all of the transformation from the low-temperature phase martensite phase to the high-temperature phase austenite phase) occurs, most of the solute atoms form a solid solution, and are equivalent to the solution treatment. The effect can be obtained. However, since the solution treatment temperature is low,
Microsegregation remains because diffusion of solute atoms dissolved from the precipitate is not sufficient. This micro-segregation is rich in the austenite phase-forming elements copper and nickel, so that the average Ac1
Austenite transformation occurs at a temperature lower than the transformation temperature (referred to as reverse transformation austenite), which contributes to improvement in toughness.

Since the austenitic phase has excellent corrosion resistance and does not involve deterioration of the corrosion resistance at the boundary with the martensite phase, there is no problem in use in a corrosive environment such as seawater. If the second solution heat treatment temperature is higher than 840 ° C., a large structural member is significantly deformed during heat treatment, so a large restraining jig is required, and cost and time required for the increase in man-hours are increased. Leads to an increase. On the other hand, when the temperature is lower than 730 ° C., a sufficient solid solution of solute atoms required for the solution treatment cannot be performed.
Therefore, the second solution treatment temperature is set to 730 to 840.
° C.

In the second aging treatment, the quenched martensitic structure is turned into a tempered martensitic structure by the second solution treatment, and the solute atoms dissolved in the solid solution are mixed with a metal called an ε phase rich in copper and nickel. This is performed in order to precipitate as a compound and obtain an appropriate strength. In addition, as described above, reverse transformation austenite appears by this heat treatment, and high toughness can be obtained. If the aging treatment temperature exceeds 630 ° C., overaging softening occurs and the strength becomes low, so that necessary and sufficient strength cannot be obtained. Also, 52
At a temperature lower than 0 ° C., the aging precipitation is insufficient, resulting in an unnecessarily high strength and a decrease in ductility.

Next, the reason for limiting the temperature control method as the second point in the present invention will be described. Normally, in the heat treatment method of the material of the present invention, there is no regulation on the rate of temperature increase and temperature decrease in the solution treatment and the aging treatment, and the temperature is raised rapidly to save fuel cost, or water or oil. Cooling at a relatively high speed such as quenching or air cooling is applied. However, in the case of a structural member mainly targeted by the present invention, it is often a welded structure, and even if it is not a welded structure, it may be a thin large-sized structure. There was a problem that the shape could not be maintained. Therefore, in the present invention, as described above, in order to prevent deformation of the structural member in the second solution treatment, a heat treatment at a lower temperature than the conventional one is selected, and the rate of temperature rise and fall is specified. The deformation of the structural member can be prevented by minimizing the temperature difference between the parts. At this time, the rate of temperature rise and fall was 100
If the heat treatment is performed at a high rate exceeding ℃ / hour, the deformation accompanying the heat treatment becomes remarkable even at the second solution treatment temperature where the heating temperature is lower than the conventional one. Therefore, the rate of temperature rise and fall should be 100 ° C./hour or less.

When the material to be subjected to the heat treatment is directly placed in a heating furnace, if the material is large, the material is locally heated by radiant heat from the heating furnace. For this reason, the material is wrapped in a metal plate (referred to as a muffle) to prevent local heating of the material due to radiant heat, and the entire muffle is heated to reduce the temperature difference, thereby further preventing deformation of the material. . The use of this muffle not only prevents radiant heat during the heating process, but also prevents local cooling due to air blown from outside the furnace during cooling, minimizing the temperature difference between each part of the material. it can.

Further, in the present invention, by maintaining the temperature in the middle of the temperature rise and the high temperature, the temperature difference of each part caused by the temperature change up to that time is corrected, and the deformation due to the volume change accompanying the transformation of the structure. Can be minimized. In the temperature rising process, there is an Ac1 transformation point (a temperature at which a high-temperature austenite phase starts to appear from a low-temperature martensite phase) near 650 ° C., and volume transformation is caused by this transformation. At this time, if the temperature difference is large in each part of the material, a difference appears in the volume change between the transformed part and the non-transformed part, which becomes stress and is applied to the material itself, resulting in deformation. For this reason, the temperature is once stopped in the range of 550 to 620 ° C. below the transformation start temperature, and after the temperature of each part of the material becomes uniform, the temperature is raised in the subsequent process. At this time, the retention temperature is 550 ° C.
If the temperature is lower than the above, a temperature difference occurs in each part of the material while the temperature is raised to the transformation temperature, and the effect of maintaining the temperature may not be obtained. Further, when the temperature is maintained at a temperature exceeding 620 ° C., some components of the present invention exceed the Ac1 transformation point. Therefore, the retention temperature during heating is 5
50-620 ° C is preferred. In the temperature-falling process, there is an Ms point (a temperature at which a high-temperature austenite phase starts to appear at a low-temperature martensite phase) near 200 ° C., and volume expansion is caused by this transformation. At this time, when the temperature difference is large at each part of the material at the time of temperature decrease as well as at the time of temperature rise, a difference appears in the volume change between the transformed part and the non-transformed part, which becomes stress and is added to the material itself, As a result, deformation will occur. Therefore, the temperature of 3 which is higher than the transformation start temperature
The temperature is stopped once in the range of 00 to 220 ° C., and after the temperature of each part of the material becomes uniform, the temperature is lowered to the subsequent step. At this time, if the retention temperature is higher than 300 ° C., a temperature difference occurs in each part of the material while the temperature is lowered to the transformation temperature, and the effect of retaining may not be obtained. Further, if the temperature is kept at a temperature lower than 220 ° C., some of the components of the present invention may exceed the Ms transformation point, and the effect of the retention may not be obtained. Therefore, the holding temperature at the time of cooling is preferably 300 to 220 ° C.

[0040]

An embodiment of the present invention will be described below.

(Materials) The test materials were melted for the components shown in Table 1 in a 25-ton electric furnace, refined in a 30-ton ladle refining furnace, and used as an electrode for secondary melting by a downward pouring method. Then, remelting was performed in an electroslag remelting furnace (ESR furnace) to obtain a material for forging. Then, it was made into a plate material having a thickness of 65 mm by forging and subjected to a test. Heat treatment for the material is 10
After the first solution treatment at 40 ° C. for 1 hour, an aging treatment at 595 ° C. for 4 hours was performed. Hereinafter, the material subjected to this processing is referred to as the present material.

(Experiment 1) Table 2 shows the mechanical properties of the material thus obtained. The material 1 was processed into the shape shown in FIG.
Welding was performed to obtain a welded joint. Note that L _{1 in} FIG.
5 mm, L ₂ is 20 mm, L ₃ is 0.5 mm, θ ₁ is 5
° and θ ₂ are 20 °. The welded joint thus obtained was subjected to a second solution treatment and an aging treatment, followed by a reliability test, and the test results in Tables 4 and 5 were obtained. In the second solution treatment and aging treatment, rapid heating and air cooling are used without intentionally controlling the heating / cooling rate.

As is clear from Tables 4 and 5, the test material subjected to the method of the present invention can stably obtain high toughness as compared with the comparative heat treatment, and can be said to be an excellent heat treatment method.

(Experiment 2) A length of 500 mm and a width of 20 mm
The long sides of two plates of this material having a thickness of 0 mm and a thickness of 27 mm were joined together, and a beam current of 160 mmA and an acceleration voltage of 70 K
V, convergence current 1205 mmA, welding speed 200 mm / m
In the condition of in, electron beam welding is performed to make a welded joint,
The same solution treatment and aging treatment as in the above example were performed to perform a reliability test, and the test results in Table 6 were obtained.

(Experiment 3) Further, in order to alleviate the heat treatment distortion caused by heating and cooling during the heat treatment, the heating rate and the cooling rate in the second solution treatment and the aging treatment were controlled to the target of 50 ° C./hour. Meanwhile, the same heat treatment and welding as described above were performed on the material. The member thus obtained was subjected to the same mechanical test as described above. Table 7 shows the results. From Table 7, it can be seen that the toughness is much better than the conventional one, and that the same properties as those in Tables 4 and 6 can be obtained in practice.

(Experiment 4) Next, in order to reduce the heat treatment distortion even in a larger member, the material was length: 3 m, width: 5
Formed into a plate shape of 0 cm, thickness: 60 mm, frontage: 5 m8
0 cm, height: 4 m, depth: 25 m, placed in an oil-fired heating furnace, subjected to a second solution treatment and a second aging treatment,
The amount of deformation of the material before and after the heat treatment was measured. Table 8 shows the measurement results. The muffle in this table is a container made of a metal plate. In this experiment, as shown in FIG. 2, a muffle 2 made of JIS SUS 304 stainless steel and having a length of 2 m and a length of 15 m and a length of 15 m was used, a base 4 was provided in the muffle 2, and both sides were sandwiched by jigs 3 for holding test materials. Test material 1 was fixed.

The test material has a length of 3 as shown in FIG.
m, a width of 600 mm, and a thickness of 50 mm were used, and the amount of deformation was measured as the amount of displacement δ from 1a before the second solution treatment and aging treatment to 1b after the treatment in the plate thickness direction.

As is clear from the results shown in Table 8, the amount of deformation of the raw material due to the heat treatment can be suppressed to a very low level by applying the temperature control and the muffle during the heat treatment.

(Experiment 5) Finally, in order to confirm the effect of the above-mentioned muffle on the welded material, Table 3 was used for the present material.
TIG welding was carried out under the same welding conditions as in. Further, the welded plate was cut out to the same size as above, put into the muffle, charged into the oil-fired heating furnace, and heated at 790 ° C.
A second solution treatment for 3 hours and a second aging treatment at 570 ° C. for 4 hours were performed. In addition, the heating rate and the cooling rate of this heat treatment were both controlled so as to be 50 ° C./hour, and a sub-zero treatment was performed for cooling just after the second solution treatment.

As a result, the deformation caused by the heat treatment in the case where both welding and muffle treatment were performed by the method of the present invention was as small as that of Table 8 and excellent as shown in Table 9. It was confirmed that mechanical properties were obtained.

(Microstructure Observation) Further, the metal structure of this member was examined. The structures by an optical microscope are shown in FIGS. 4 (100 ×) and 5 (300 ×). As shown in FIGS. 4 and 5, only a martensite phase was found under an optical microscope.
When this member was further investigated by X-ray diffraction, it was confirmed that the material of the present invention contained 6% or more of the reverse transformed austenite phase (γ) as shown in Table 10. These reverse transformed austenite phases are finely formed on a part of the martensite lath. Further, when this member is observed with an electron microscope, fine ε-phase precipitation can be confirmed.

(Passenger Boat) An example of a high-speed passenger boat to which the structural member of the present invention is applied will be described with reference to FIGS.

In this passenger boat, wings 16 are provided on the front and rear portions of the hull 11 via wing columns 17 respectively. Hull 11
Is provided with a water pipe 20 communicating with the wing column 17 on the stern side. The pot-type suction port 15 is provided at the inlet end of the water pipe 20 of the wing column 17, and the jet is provided at the end of the hull 11 side. Each has a nozzle 21. The water flow is
Is accelerated by a pump 12 provided in the
2 is driven by a propulsion engine 13.

As shown in FIG. 7, this embodiment is of a catamaran type, and two wing supports 17 are provided at each of the front and rear portions of the ship.
Has been fixed. 8 and 9 show enlarged views of the wing 16 and the wing column 17 on the bow side and the stern side. The cross-sectional shapes of the wing 16 and the wing column 17 are substantially lens-shaped or streamlined. The rear part of the wing column 17 on the bow side is a rudder flap 18, and the high-speed passenger boat can be turned left and right by turning left and right respectively. The rear portions of the front and rear wings 16 are flaps 19, respectively, and rotate up and down to control the high-speed passenger boat up and down.

A structural member manufactured by the same method as in Experiment 5 is used as the wing 16 described above. According to this method, the structural member obtained is prevented from being deformed during the heat treatment and has excellent toughness. The use of this as the wing 16 provides the following advantages to the high-speed passenger boat.

(1) Since the blades are long, if the wings have an uneven deformation, the pitch changes in the middle of the wings, and the generated lift becomes uneven. In extreme cases, the lift is reversed. However, by using the wings of the present invention having excellent uniformity, the pitch and the lift become uniform, and the lift control, that is, the boat's vertical mobility is improved.

(2) Fluid resistance increases if the shape of the wing that reduces the fluid resistance as much as possible becomes non-uniform, but the wing according to the present invention can reduce the fluid resistance and propulsion efficiency. Can be turned.

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

[Table 3]

[0061]

[Table 4]

[0062]

[Table 5]

[0063]

[Table 6]

[0064]

[Table 7]

[0065]

[Table 8]

[0066]

[Table 9]

[0067]

[Table 10]

[0068]

According to the structural member and the method of manufacturing the same of the present invention, it is possible to heat-treat a large welded structural member after welding, which cannot be performed by a conventional heat-treating method, and to harden a welded portion after heat-treating. The thickness distribution became homogeneous, and in addition, it was possible to have excellent toughness that could not be obtained by conventional heat utilization methods. In addition, by applying the present invention, the deformation of the material during the heat treatment can be extremely reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a groove shape before welding of a TIG welding test piece.

FIG. 2 is a diagram illustrating a shape of a muffle example.

FIG. 3 is a diagram illustrating a deformation amount of a test piece.

FIG. 4 is a cross-sectional metal structure photograph by an optical microscope.

FIG. 5 is a cross-sectional metallographic photograph by a light microscope.

FIG. 6 is a schematic structural view of a hydrofoil.

FIG. 7 is a front view of a hydrofoil.

FIG. 8 is a perspective view of a bow wing.

FIG. 9 is a perspective view of a stern wing.

[Explanation of symbols]

 1 test material 16 hydrofoil

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shinsuke Oba 5-717-1 Fukadori-cho, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries, Ltd. Nagasaki Research Laboratory (72) Inventor Makoto Nakamura 2-5-2 Marunouchi, Chiyoda-ku, Tokyo No. 1 Inside Mitsubishi Heavy Industries, Ltd. (72) Inventor Hidetoshi Sueoka 1-1, Akunouracho, Nagasaki City, Nagasaki Prefecture Inside Mitsubishi Heavy Industries, Ltd. Nagasaki Shipyard (72) Inventor Fumikazu Sakai 1-1, Akunouracho, Nagasaki City, Nagasaki Prefecture No. Mitsubishi Heavy Industries, Ltd. Nagasaki Shipyard (72) Inventor Manabu Kimura 1-1, Akunouramachi, Nagasaki City, Nagasaki Prefecture Mitsubishi Heavy Industries, Ltd. Nagasaki Shipyard (56) References JP-A-63-53246 (JP, A) JP-A-61-147855 (JP, A) JP-A-51-49117 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C22C 38/00-38/60 C21D 6/00

Claims (11)

(57) [Claims] 1. Carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to 5 by weight
%, Nickel: 3 to 5.5%, chromium: 14 to 17.5
%, Molybdenum: 0.5% or less, niobium: 0.15-
0.45% and a balance substantially composed of iron, and an ε phase is precipitated in a matrix composed of an austenite phase of 6 to 30% by volume and a balance substantially composed of a martensite phase. Structural member with high toughness and small heat distortion. 2. A hull, a propulsion device provided at the rear of the hull, and provided substantially below the hull in a substantially horizontal orientation, the weight ratio of carbon: 0.07% or less, silicon: 1% or less, Manganese: 1% or less, Copper: 2.5 to 5%, Nickel: 3 to 5.5%, Chromium: 14 to 17.5%, Molybdenum: 0.5% or less, Niobium: 0.15 to 0.45 % And a balance substantially consisting of iron, and a stainless steel having a structure in which an austenite phase is 6 to 30% by volume and the remainder is substantially a martensite phase in which a ε phase is precipitated in a matrix. A ship with hydrofoils. 3. A weight ratio of carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to 5
%, Nickel: 3 to 5.5%, chromium: 14 to 17.5
%, Molybdenum: 0.5% or less, niobium: 0.15-
A structure in which a first solution treatment is performed at 1010 to 1050 ° C on stainless steel of 0.45% and the balance substantially consisting of iron, and then the first aging treatment is performed at 520 ° C to 630 ° C. A method for manufacturing a structural member, further comprising performing a second solution treatment at 730 to 840 ° C. and then performing a second aging treatment at a temperature of 520 ° C. to 630 ° C. in the member manufacturing method. 4. A weight ratio of carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to 5
%, Nickel: 3 to 5.5%, chromium: 14 to 17.5
%, Molybdenum: 0.5% or less, niobium: 0.15-
A structure in which a first solution treatment is performed at 1010 to 1050 ° C on stainless steel of 0.45% and the balance substantially consisting of iron, and then the first aging treatment is performed at 520 ° C to 630 ° C. In the method of manufacturing a member, a structural member having an arbitrary shape is formed by welding, and then the second solution treatment is carried out in 7
After performing at 30 to 840 ° C, the second aging treatment is performed at 520 ° C.
A method for producing a structural member, which is performed at a temperature of 630 ° C. or lower. 5. A weight ratio of carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to 5
%, Nickel: 3 to 5.5%, chromium: 14 to 17.5
%, Molybdenum: 0.5% or less, niobium: 0.15-
After performing a first solution treatment at 1010 to 1050 ° C. on stainless steel of 0.45% and the balance substantially consisting of iron, a first aging treatment is performed at 520 ° C. to 630 ° C. The temperature is raised at a rate of not more than ℃ / hour, a second solution treatment is performed at 730-840 ° C., and then cooled to room temperature at a cooling rate of not more than 100 ° C./hour in a furnace;
A method for producing a structural member, further comprising performing a second aging treatment at a temperature of 520 ° C. or more and 630 ° C. or less, and thereafter cooling to room temperature in a furnace at a cooling rate of 100 ° C./hour or less. 6. A weight ratio of carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to 5
%, Nickel: 3 to 5.5%, chromium: 14 to 17.5
%, Molybdenum: 0.5% or less, niobium: 0.15-
After performing a first solution treatment at 1010 to 1050 ° C. on stainless steel of 0.45% and the balance substantially consisting of iron, the first aging treatment is aged at 520 ° C. to 630 ° C. and welded As a structural member having an arbitrary shape, the temperature is further increased at a rate of 100 ° C./hour or less, a second solution treatment is performed at 730-840 ° C.
After cooling to room temperature at a cooling rate of 0 ° C./hour or less, the second
Aging treatment at 520 ° C. or more and 630 ° C. or less, and thereafter cooling to room temperature at a cooling rate of 100 ° C./hour or less in a furnace. 7. Carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to 5 by weight ratio
%, Nickel: 3 to 5.5%, chromium: 14 to 17.5
%, Molybdenum: 0.5% or less, niobium: 0.15-
After performing a first solution treatment at 1010 to 1050 ° C. on stainless steel of 0.45% and the balance substantially composed of iron, the first aging treatment is aged at 520 ° C. to 630 ° C. The material is put in a container made of a plate of the above, and the temperature of the material together with the container is raised at a rate of 100 ° C./hour or less, a second solution treatment is performed at 730 to 840 ° C., and then in a furnace After cooling to room temperature at a cooling rate of 100 ° C./hour or less, the second aging treatment is performed at 520 ° C. to 630 ° C.
A method for producing a structural member, comprising the steps of: performing cooling in a furnace at a cooling rate of 100 ° C./hour or less; 8. Carbon: 0.07% or less, silicon: 1% or less, manganese: 1% or less, copper: 2.5 to 5 by weight ratio
%, Nickel: 3 to 5.5%, chromium: 14 to 17.5
%, Molybdenum: 0.5% or less, niobium: 0.15-
After performing a first solution treatment at 1010 to 1050 ° C. on stainless steel of 0.45% and the balance substantially consisting of iron, the first aging treatment is aged at 520 ° C. to 630 ° C. and welded The material is put in a container made of a metal plate, and the material is heated together with the container at a rate of 100 ° C./hour or less to perform a second solution treatment. 730-840 ° C., and then cooled in the furnace to room temperature at a cooling rate of 100 ° C./hour or less,
Further, a method for producing a structural member, wherein a second aging treatment is performed at 520 ° C. or more and 630 ° C. or less, and then cooled to room temperature in a furnace at a cooling rate of 100 ° C./hour or less. 9. When the temperature of the material reaches 550.degree. C. to 620.degree. C. in the temperature raising step of the second solution treatment, the temperature is maintained for 30 minutes to 2 hours to equalize the temperature of each part of the material. The method for producing a structural material according to any one of claims 5 to 8, wherein the temperature is raised to a second solution heat treatment temperature after waiting. 10. When the temperature of the raw material reaches 300 ° C. to 220 ° C. in the temperature lowering step of the second solution treatment, the temperature is maintained for 30 minutes to 2 hours to equalize the temperature of each part of the raw material. The method for producing a structural material according to any one of claims 5 to 8, wherein the temperature is lowered to room temperature after waiting. 11. When the temperature of the raw material reaches 300.degree. C. to 220.degree. C. in the temperature lowering step of the second solution treatment, the temperature is maintained for 30 minutes to 2 hours to make the temperature of each part of the raw material uniform. The method for producing a structural material according to claim 9, wherein the temperature is lowered to room temperature after waiting.