JPH0148339B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing an endless belt for a belt conveyor, and more particularly, the present invention relates to a method for manufacturing an endless belt for a belt conveyor, and more particularly, the present invention relates to a method for manufacturing an endless belt for a belt conveyor. Concerning a method of manufacturing a conveyor belt. Stainless steel conveyor belts have excellent properties such as corrosion resistance, heat resistance, oil resistance, and abrasion resistance, so they are used not only for conveying general objects but also for oven conveyors, frozen conveyors, press conveyors, calendar conveyors, etc. As a conveyor belt that involves heat treatment and processing of objects,
Widely used in food processing industry, general chemical industry, machinery industry, electrical industry and other fields. No matter the application, this stainless steel conveyor belt is continuously tensioned between rollers, such as between the head and tail drums or between the drive end pulley and the tension pulley. passed on. For this reason, it is necessary to form an endless stainless steel plate or steel strip by strongly joining the ends thereof. As for this joining, joining by rivets and joining by welding are known. Since riveting has the problem of impairing the surface flatness of the belt and causing stress concentration due to repeated application of stress through rotation, it is desirable to join by welding if possible. Conventionally known stainless steel conveyor belts are work-hardened stainless steels made of austenitic stainless steel such as SUS301 or SUS304 and hardened by cold rolling, or work-hardened stainless steels made by the same applicant. A typical example is a belt manufactured from martensitic stainless steel described in Japanese Patent Publication No. 51-31085. The former work-hardened stainless steel belt cannot be formed into a high-strength belt by welding joints. This is because when endlessly joined by welding, the welded part becomes soft due to heat input, and the strength becomes lower than the strength of the material. Furthermore, when this belt is applied to a conveyor that undergoes a heating and cooling cycle, such as an oven conveyor, it causes a change in shape. This is because the steel of this belt has a two-phase structure consisting of a deformation-induced martensite phase and an austenite phase. This also makes it difficult to carry out the known process of heat-pressing a rubber belt to the backside of the belt to prevent it from meandering. This is because the belt is deformed into a wave shape during heating during this process. Furthermore, even if this belt is joined by riveting instead of welding, the tensile strength is at most 110Kg/mm ² and the hardness is 350Hv.
However, the design of the conveyor is restricted and its applications are limited. The latter belt made of martensitic stainless steel described in Japanese Patent Publication No. 51-31085 has the same strength as the material even if a welded joint is used. Since the joint becomes an endless belt and substantially no deformation occurs due to heating and cooling, the former problem can be avoided. The chemical composition values of the steel of this belt are C: 0.03~0.06wt.%, Si: 0.5~
1.0wt.%, N; 0.03wt.% or less, Ni; 3 to 10wt.
%, Cr; 10-18wt.%, and preferably Ti;
(Cwt.%+Nwt.%)×5 to 16. However, like the previous belt, this belt also has a tensile strength of at most 110 Kg/mm ² and a hardness of about 380 Hv. Therefore, this conveyor belt can only be applied to conveyor belts that have such mechanical properties within an acceptable range. The purpose of the present invention is to overcome the application limits of the previously known stainless steel conveyor belts as described above. Another object of the present invention is that the strength and hardness of the welded part of a conveyor belt formed endlessly by welded joints are lower than those of the non-welded part, and are substantially equivalent to those of the non-welded part. Therefore, both welded and non-welded parts have higher strength and hardness than conventional stainless steel conveyor belts, and also have excellent fatigue strength and other useful properties of stainless steel. Obtaining an endless conveyor belt of welded joints with properties,
Furthermore, it is important to manufacture this with good manufacturability. The method for producing an endless conveyor belt made of stainless steel according to the present invention includes C of 0.07wt.% or less, N of 0.03wt.% or less, 0.5~
2.5wt.% Si, 4.0wt.% or less Mn, 5.0~9.0wt.%
Ni, 12.0~17.0wt.% Cr, 0.5~2.5wt.%
Cu, 0.2 to 1.0wt.% Ti, 1.0wt.% or less Al, provided that the A value according to the following formula is less than 41.0, A = 17 × (Cwt.%/Tiwt.%) + 0.70 × (Mnwt. %)＋1×(Niw
t.%) + 0.60 x (Crwt.%) + 0.76 x (Cuwt.%) - 0.63 x (Alwt.%) + 20.871 Stainless steel with the balance being Fe and impurity elements inevitably mixed in during manufacturing. The sheet or strip is solution-treated in the process of manufacturing the sheet or strip, and optionally subsequently temper-rolled at a rolling reduction of less than 50% to reduce the structure of the steel to substantially martensitic. The obtained sheet or strip having a substantially martensitic structure is cut into a predetermined size, and the ends of the cut sheets or strips are joined by welding to form an endless belt of a predetermined size. It is characterized by forming an endless belt and subjecting the entire obtained endless belt to an aging treatment. The endless belt obtained by the method of the present invention has a metal structure in which one or more selected from the above alloying elements and compounds thereof are precipitated in the martensitic phase in both the welded and non-welded parts. Both welded and non-welded parts of this endless belt have a tensile strength of 140Kg/mm2 ^or more, a hardness of 430Hv or more, and a fatigue strength of 50Kg/mm2.
^mm2 or more. More preferably, the endless belt obtained by the method of the present invention has a tensile strength of the non-welded part.
160Kg/mm2 or ^more , the tensile strength of the welded part is at least 90% of that of the non-welded part, and the hardness of the non-welded part is
At 480Hv or higher, the hardness of the welded part is at least 90% of that of the non-welded part, and the fatigue strength of the non-welded part is
At 57Kg/mm2 or ^more , the fatigue strength of the welded part is at least 90% of that of the non-welded part. It is understood that the stainless steel conveyor belt according to the present invention has surprisingly high performance when compared with known conveyor belts having a maximum tensile strength of 110 Kg/mm ² and a maximum hardness of about 380 Hv. It will be. Moreover, this performance is achieved through welded joints rather than riveted joints. The conveyor belt according to the present invention should also sufficiently satisfy other properties desired for a conveyor belt, such as proof stress and other properties, as shown in the Examples below. To explain more specifically the manufacturing method of the endless conveyor belt of the present invention, first, in the steel welding process, C of 0.07wt.% or less, N of 0.03wt.% or less, 0.5~
2.5wt.% Si, 4.0wt.% or less Mn, 5.0~9.0wt.%
Ni, 12.0~17.0wt.% Cr, 0.5~2.5wt.%
Cu, 0.2 to 1.0wt.% Ti, 1.0wt.% or less Al, provided that the A value according to the following formula is less than 41.0, A = 17 × (Cwt.%/Tiwt.%) + 0.70 × (Mnwt. %)＋1×(Niw
t.%) + 0.60 x (Crwt.%) + 0.76 x (Cuwt.%) - 0.63 x (Alwt.%) + 20.871. A specified steel plate or steel strip is produced on the steel strip manufacturing line, but in the final process, this steel plate or steel strip is subjected to solution treatment to make the steel structure substantially martensitic, and during the solution treatment If the austenite phase still remains, this steel plate or steel strip is further temper-rolled (cold rolled) at a cold rolling reduction of 50% or less to transform this phase into a strain-induced martensitic phase. The obtained steel plate or steel strip having a substantially martensitic structure is cut into belt pieces having predetermined long dimensions, and the ends of the belt pieces are joined by welding to form an endless belt having a predetermined shape and size. It can be advantageously manufactured through the following steps: forming a belt and subjecting the resulting endless belt to an aging treatment as a whole. As a modified method, a steel plate or steel strip having a martensitic structure that has been solution-treated and, if necessary, further cold-rolled, or a belt piece obtained by cutting the same, may be subjected to an aging treatment. In this case, after welding, the welded portion is subjected to aging treatment. In these processes, the solution treatment can be combined with the annealing treatment after cold rolling, and the solution treatment temperature can be in the temperature range of 900 to 1050°C. Cooling from this temperature to room temperature may be done by air cooling or water cooling. Aging treatment preferably at 425-550℃
Temperature range of 450-525℃ for 10-300 minutes, preferably
Preferably, the treatment is held for 10 to 60 minutes. In the case of aging treatment after welding, it is preferable to perform the aging treatment after the welded part is hammered, for example, with a hammer or the like. Instead of this hammer processing, -20℃
A sub-zero process of cooling for about 30 minutes may be performed below, or a further process of hammering may be added after the sub-zero process. In addition, in the process of manufacturing steel plates or steel strips, if temper rolling is performed after solution treatment (annealing treatment), the rolling reduction during temper rolling is
If it exceeds 50%, it will cause deterioration of the toughness of the conveyor belt, so it is preferable to keep it below 50%. This skin pass rolling generally has higher strength than as-annealed belts, so it is a useful process for obtaining conveyor belts with higher tensile strength. The butt welding method for welding the belt pieces can be carried out by methods known to those skilled in the art, such as electric welding, gas welding or other suitable methods. The conveyor belt of the present invention includes, for example, the first to sixth conveyor belts.
It is suitable for various conveyors or article processing or processing equipment as shown in the figure. In each illustrated example, a conveyor belt 1 according to the invention
is stretched endlessly between the drive pulley 2 and the tension pulley 3, and is used to adjust the tension device attached to the tension pulley 3, such as a spring tension device, gravity weight device, or pneumatic or hydraulic tension device. Therefore, the relative distance between the drive pulley 2 and this tension pulley 3 is expanded or contracted, thereby adjusting the tension applied to the conveyor belt. The conveyor shown in FIG. 1 has a long traveling distance and has an inflection section, and shows an example in which the conveyor belt 1 needs to be stretched under high tension. FIG. 2 shows a calender device in which a workpiece is passed between two sets of upper and lower conveyor belts, and the workpiece is shaped and polished at the same time by the clamping pressure and heating of the upper and lower belts. At this time, clamping pressure is applied by the carrier roller 4, and heating is performed by the heating means 5. The apparatus of FIG. 2 is useful for manufacturing plywood, rolling or shaping synthetic resins, manufacturing tiles and fireproof boards, and the like. FIG. 3 shows a conveyor for conveying heavy weight or acutely angled metal parts 6 and the like. FIG. 4 shows a conveyor with a furnace 7 on its running path. FIG. 5 shows a conveyor equipped with a liquid tank 8 on its travel path. This liquid tank 8 is a chemical liquid, cooling water, or the like. FIG. 6 shows a conveyor equipped with hot air supply means 9. In the case of this FIG. 6, the conveyor belt 1 according to the present invention
A large number of holes are drilled in the hole so that the hot air directly contacts the object to be treated. These illustrated conveyors and article processing devices are examples to which the conveyor belt of the present invention can be suitably applied, but in addition to these,
Various application examples can be considered by utilizing the inherent properties of stainless steel such as heat resistance, corrosion resistance, and beautiful surface of the conveyor belt of the present invention, as well as high tensile strength and hardness not found in conventional stainless steel belts. . Examples include vibration application devices for automobile driving tests, moving walkways, and belt flakers. The conveyor belt of the present invention applied as described above has a special structure in which the stainless steel of the belt metal has a specific chemical composition value as described above, and the non-welded part and the welded part of this belt are substantially equal. It is characterized by having a unique metal structure. Taking only the chemical composition values of the stainless steel of the conveyor belt according to the present invention, several of the present inventors have published Japanese Patent Application No. 51-131610 (Japanese Unexamined Patent Publication No. 53-57114) and Japanese Patent Application No. 51- No. 131611 (Japanese Unexamined Patent Publication No. 53-57115)
There are some similarities in the chemical composition values of stainless steel for springs described in the specification of . However, what is described in these specifications is the spring material,
A new stainless steel invention has been disclosed that has the properties required for springs. Therefore, the C value is different from the steel for the conveyor of the present invention, and in the above spring material, it is necessary to limit the Cr equivalent/Ni equivalent and H value, which are not required in the present invention, to a specific range. It was essential, and the A value was also specified by another formula. Using the common knowledge of those skilled in the art, it would be unexpected to weld a spring material. That is, it is unprecedented that a spring component is fixed or processed by welding. Therefore, even in the above-mentioned inventions of spring materials, no consideration was given to the weldability thereof, nor was this mentioned in their specifications. The conveyor according to the present invention is an endless belt having welded joints, and unlike the above-mentioned spring material, the chemical composition value of steel is also taken into consideration for the purpose of welding, and in terms of its metallographic structure, there are welded and non-welded parts. The department has an equivalent organization. Moreover, the present invention was made with the aim of satisfying various requirements that could not be met with conventional stainless steel conveyor belts. For this purpose, the chemical composition of the steel of the conveyor belt of the present invention and its content are: C up to 0.07wt.%, N up to 0.03wt.%, 0.5~
2.5wt.% Si, 4.0wt.% or less Mn, 5.0~9.0wt.%
Ni, 12.0~17.0wt.% Cr, 0.5~2.5wt.%
Cu, 0.2 to 1.0wt.% Ti, 1.0wt.% or less Al, provided that the A value according to the following formula is less than 41.0, A = 17 × (Cwt.%/Tiwt.%) + 0.70 × (Mnwt. %)＋1×(Niwt.
%)+0.60×(Crwt.%)+0.76×(Cuwt.%)−0.63×(Alwt.%)+20.871. The reasons for this identification are summarized below. C: About 0.07% or less. If C is too high, the strength of the martensitic phase increases, which requires a lot of effort in rolling, etc. when manufacturing steel plates or steel strips, and also causes a large amount of retained austenite to be present in the welded part due to redissolution of C during welding. Therefore, a sufficient martensitic structure cannot be obtained through post-treatment, and sufficient welded joint strength as a conveyor belt cannot be obtained. For this reason, C was set at 0.07% or less. Furthermore, if the C content is increased, it is necessary to increase the amount of Ti added for precipitation strengthening, and adding a large amount of Ti will harm the surface texture. Furthermore, it impairs the fluidity of molten metal during welding, and the formation of Ti oxide makes it difficult to obtain a good weld bead. This is also one of the factors that made the C content less than 0.07%. N: About 0.03% or less. N has a strong affinity with Ti, which is a precipitation strengthening element.
If it is made too high, large inclusions are formed in TiN, which causes a decrease in toughness, and also becomes a starting point for fatigue failure due to repeated bending stress for conveyor belts in use. Therefore, N is 0.03%
The following was made. Si; about 0.5-2.5%. Si is one of the elements that causes precipitation hardening, and if it is less than 0.5%, the effect is small, and in order to fulfill the function of a high-strength conveyor belt, it is necessary to increase the amount of Ti added, which reduces the adverse effects of Ti addition. arise. In addition, Si is necessary to improve the fluidity of molten metal during welding, and if it is less than 0.5%, the fluidity decreases, so the surface bead is likely to undercut during welding, reducing welding strength. For this reason, the lower limit was set at 0.5%. Moreover, since no effect on increasing strength was observed even if the amount was added in excess of 2.5%, the content was limited to 2.5%. Furthermore, increasing the Si content promotes the formation of the δ-ferrite phase, which reduces the rupture life due to repeated bending stress, which is a factor that shortens the life of the conveyor belt, and reduces the joint strength due to the increased amount of δ-ferrite in the weld. cause This is also one of the reasons why the upper limit of Si was set at 2.5%. Cr; about 12.0-17.0%. Cr requires an amount of at least 12.0% to obtain the corrosion resistance inherent in stainless steel;
When the amount of Cr added is high, the δ-ferrite phase is generated and retained austenite is generated, making it virtually difficult to obtain a martensitic structure, making it impossible to satisfy the function as a conveyor belt, and causing the δ-ferrite phase to form in the welded part. In particular, the amount produced increases, leading to a decrease in the strength of the welded part, making it impossible to achieve the object of the present invention. Therefore, the maximum amount of Cr is 17.0
Up to %. About Ni: 5.0-9.0%. In order to suppress the formation of δ ferrite, which causes a decrease in strength, it is necessary to increase the content of Ni along with an increase in the amount of Cr.
In order to lower the temperature, it is necessary to maintain low Ti under conditions that do not generate the δ ferrite phase. However, if it is too low, the precipitation hardening phenomenon will be reduced, making it impossible to obtain sufficient strength as a conveyor belt.
For this reason, the minimum value was set at 5.0%. On the other hand, if it is too high, a large amount of retained austenite phase will be generated, making it substantially difficult to obtain a martensitic structure, resulting in a decrease in strength, making it impossible to achieve the object of the present invention. Furthermore, it becomes necessary to perform intense cold working, and it becomes a two-phase structure of deformation-induced martensite and austenite, and when used as a conveyor belt that is repeatedly heated and cooled, the belt shape deteriorates and becomes unusable. For this reason, the maximum amount was set at 9.0%. Ti; about 0.2-1.0%. Ti is an element that exhibits precipitation hardening, and if it is less than 0.2%, its effect is small, so it was set to a minimum of 0.2%. In addition, if the amount exceeds 1.0%, surface skin deterioration,
This causes problems with the fluidity of molten metal during welding, the weld bead, etc., and also reduces toughness. In particular, a decrease in toughness may cause problems such as rupture after fatigue cracks occur due to long-term use in conveyor belts operated at high speeds used in automobile tire running tests, etc. That is, due to the decrease in notch toughness, a phenomenon occurs in which the conveyor belt breaks at the same time as cracks occur. For this reason, it was set to a maximum of 1.0%. Al: About 1.0% or less. Al can be used as a precipitation strengthening element like Ti, and can be added by partially replacing it, but the upper limit was set at 1.0% due to the relationship with toughness. Cu; about 0.5-2.5%. Cu is one of the elements that exhibits precipitation hardening.
The amount of addition is determined by the amount of Si and Ti, but
The effect is small below 0.5%. Further, even if added in excess of 2.5%, the effect is small relative to the amount added and it impairs hot workability during the production of steel plates or steel strips, so the content was set at 2.5% or less. Regarding Mn; 4.0% or less. Like Ni, Mn contributes to suppressing δ-ferrite and can be partially substituted in place of Ni. However, from the viewpoint of component balance such as suppressing effect on δ-ferrite phase and generation of retained austenite phase, substitution is recommended. The possible upper limit is 4.0%, so we set the upper limit to 4.0%. A value: less than 41.0. C, Ti, Mn, Ni, Cr, Cu, and Al are contained within the above ranges, but if the A value according to the above formula is
Adjust each component so that it is less than 41.0. The constants for the component values were laboratory confirmed during the development of the conveyor belt in accordance with the present invention. This A value
In the case of 41.0 or more, a large amount of austenite phase remains in the solution treatment state, the welded part after welding, and the heat affected zone, as shown in the examples below. The retained austenite phase in the solution-treated state can be easily converted to martensite by slight cold rolling, but the retained austenite phase in the weld zone is difficult to convert into martensite on an industrial scale, and the subsequent aging process is difficult. It cannot be strengthened sufficiently even by treatment. For this reason, during use as a conveyor belt, the belt breaks at the welded part, shortens the life of the belt, and the object of the present invention cannot be achieved. Furthermore, as the A value increases, it is necessary to perform strong cold working, and a two-phase structure of deformation-induced martensite and austenite phase develops.
Conveyor belts that are repeatedly heated and cooled may become deformed, or the shape of the belt may deteriorate when a rubber belt is heat-pressed and attached to the back of the belt to prevent meandering. Therefore, the A value according to the above formula needs to be less than 41.0. The conveyor belt of the welded joint of the present invention is made of stainless steel containing a specific amount of the components specified based on the above reasons, and both the non-welded and welded parts are made of martensite. It is characterized by having a metallic structure in which intermetallic compounds of alloying elements are precipitated in the phase. Such a structure can be easily obtained by the manufacturing method according to the present invention. Thus, the present invention provides a high strength welded joint stainless steel conveyor belt never before seen before. The conveyor belt according to the present invention also has sufficiently reliable fatigue strength in conveyors subjected to semi-permanent repeated bending stress, and does not undergo substantial changes in its steel structure even when subjected to repeated heat cycles. , there is no problem of deterioration of the function as a conveyor belt, such as deterioration of flatness or deterioration of toughness or rigidity. The present invention will be specifically explained below based on Examples. Table 1 shows the chemical composition values (% by weight) and A values of the conveyor belt steel materials used in the test.
In Table 1, Samples No. N-1 to N-6 are examples of the present invention,
N-7 and 8 are comparative examples other than those specified in the present invention, M
-1 is an example within the composition range of Japanese Patent Publication No. 51-31085 by the same applicant, and SUS301 and SUS304 steel belts are commercially available examples. Table 2 shows the mechanical properties of the inventive examples and comparative examples before and after aging treatment (manufacturing conditions and treatment conditions will be detailed later). Table 3 shows the mechanical properties of the welded parts of the inventive examples and comparative examples (welding conditions will be described later). In addition, Fig. 8 shows the hardness changes of the present invention example and the comparative example of the welded part shown in Fig. 7, and Figs. 9 to 12 show the non-welded part and the welded part (hatch part). The proof stress, tensile strength, spring limit value, and fatigue strength of the present invention example and comparative example are shown in graphs.

【table】

【table】

【table】

[Table] From these Tables 2 to 3 and Figures 8 to 12, it will be understood that the conveyor belt according to the present invention has extremely superior conveyor belt characteristics as compared to the comparative example and the conventional example. The manufacturing conditions, test conditions, and various characteristics of each of the examples will be individually explained below. In the examples shown in Table 2, the invention examples N-1 to
6 and Comparative Examples N-7 and 8 are the annealed material (solution treatment state) and the cold rolled material that was further cold rolled by 20% before the aging treatment and at 480°C.
Comparative example M-1 is annealed and aged at 450°C for 1 hour.
SUS301 and SUS304 steel belt materials are commercially available and are aged at 400°C for 1 hour. As shown in Table 2, the examples of the present invention exhibit mechanical properties equivalent to those of other comparative examples before aging even in the solution-treated or temper-rolled state. However, the properties of the examples of the present invention after aging treatment are significantly better than those of M-1, SUS301, and SUS304. For example, when comparing the tensile strength of these conventional examples, it is around 115 Kg/mm ² at most, whereas the examples of the present invention have a tensile strength of 150 Kg/mm ² or more for solution-treated materials, and 175 Kg/mm ² or more for temper-rolled materials. shows a high value of Comparative Examples N-7 and N-8 have A values outside the specifications of the present invention, but in the solution treatment state, the strength is low even after aging treatment. In addition, after temper rolling, they show mechanical properties equivalent to those of the present invention examples both before and after aging treatment, but in this case, a large amount of austenite phase remains in the heat affected zone after welding, so it is easy to After post-treatment, it is difficult to easily convert to martensite, and as shown in Table 3, the strength of these welded joints is low. That is, as is clear from Table 3 showing the test values of welded parts, compared to the yield strength, tensile strength, and spring limit value kb of Invention Examples N-1 to N-6, these N-7,
8 shows a low value and does not achieve the purpose of the present invention. All of the properties in Table 3 are the properties after TIG welding and after aging treatment in which the welded part was hammered. In addition, M-1, which is within the composition range of low carbon martensitic stainless steel for steel belts shown in Japanese Patent Publication No. 51-31085 by the same applicant, is also A.
In terms of values only, this A value is less than 41.0, which meets the requirements of the present invention. However, this steel is not a precipitation hardening type steel, and its strength and hardness after aging treatment are very low compared to the examples of the present invention, as shown in Table 2. FIG. 8 shows the change in hardness of the welded portion of the conveyor belt as shown in FIG. 7. In FIG. 7, 10 is a welded part, 11 is a heat affected zone, and 12 is a non-welded part. ● mark A in FIG. 8 is the present invention example N-2,
After TIG welding the end of the belt material, which is a steel strip (20% temper rolled) with a thickness of 1.0 mm, width of 1000 mm, and length of 25 m, the welded part is hammered, and then the belt material is tested using a belt physical testing machine equipped with a heating furnace. The welded part was cut out from the belt that was formed by attaching the belt to a heating furnace set at 480°C, rotating the belt at low speed, and aging the entire length for approximately one hour. Circle B is Invention Example N-2. After TIG welding a steel strip with the same dimensions as A, the vicinity including the welded part was placed in a liquid phase whose temperature was adjusted to -25°C with alcohol and dry ice for 30 minutes. It was cut from a belt formed by immersion and sub-zero treatment, and then aging treatment in the same manner as A. ▲ mark C is invention example N-5, which was cut out from a steel strip (annealed material) with the same dimensions as A that was subjected to TIG welding and then subjected to aging treatment in the same manner as A. □ mark D is Comparative Example M-1, which was prepared by the same method as the inventive example. However, welding
Aging treatment was performed at 450°C for 1 hour using TIG welding without post-treatment. △ mark E is a comparative example SUS304 steel belt, which was created by the same method as the example of the present invention.
However, welding was TIG welding, post-treatment was hammer processing, and aging treatment was performed at 400℃ for 1 hour. As can be seen from FIG. 8, specimens with an A value of around 39.0 or less, such as Example N-5 of the present invention, exhibit high hardness even when subjected to aging treatment while welded. Also like N-2,
Even if the A value is around 40.0 to 41.0, it will show high hardness and be superior to conventional stainless steel belts if you apply a slight hammering or sub-zero treatment for about 30 minutes at -25℃ or below as a simple post-processing. It has good mechanical properties. Figures 9 to 12 show examples N-2 and N-5 of the present invention.
and shows the mechanical properties of the non-welded part and the welded part (hatch part) of the conventional steel belt M-1 and SUS304 steel belt. The belt used in the test was the same as that used in FIG. 8, and the non-welded and welded parts were cut out and used in the test. However, the 20% temper-rolled N-2 material is A shown in Figure 8, and the annealed N-2 material has a plate thickness of 1.0 mm.
The end of the belt material, which is a steel strip (annealed material) with a width of 1000 mm and a length of 25 m, is subjected to TIG welding and then hammered, and then installed in a belt physical testing machine equipped with a heating furnace.
The belt was set at 480°C, the belt was rotated at a low speed, and the entire length was aged for approximately one hour.The non-welded and welded parts were cut out and used for testing. Note that in FIGS. 9 to 12, hatched values indicate welded portions, and non-hatched values indicate non-welded portions. As can be seen from these Figures 9 to 12, the characteristics of the invention examples N-2 and N-5 are the same as those of the comparative examples M-1 and
Compared to SUS304 steel belt, both non-welded and welded parts have yield strength, tensile strength, spring limit value kb,
It exhibits high values such as fatigue strength, and has properties not available with conventional products. In addition, as in N-5, A
If the value is around 39.0 or less, similar to the hardness behavior shown in Figure 8, after welding, even without post-treatment such as hammering or sub-zero, it has excellent mechanical properties with only aging treatment. .

[Brief explanation of drawings]

1 to 6 are schematic cross-sectional views showing examples of conveyors using the conveyor belt of the present invention, and FIG. 1 shows a long tension conveyor, and FIG.
The figure shows a calendar conveyor, Figure 3 shows a conveyor for conveying heavy objects or objects with sharp edges, Figure 4 shows a conveyor for heat treatment, and Figure 5 shows a conveyor for liquid treatment.
FIG. 6 shows an example of a conveyor for hot air treatment. 7th
The figure is a sectional view of a welded portion of the conveyor belt of the present invention. FIG. 8 is a diagram showing changes in hardness of a welded part. 9 to 12 are graphs showing the properties of the non-welded portion and welded portion of the conveyor belt of the present invention in comparison with a comparative product and a conventional product.
The figure shows proof stress, Fig. 10 shows tensile strength, Fig. 11 shows spring limit value, and Fig. 12 shows fatigue strength. DESCRIPTION OF SYMBOLS 1... Conveyor belt, 2... Drive pulley, 3... Tension pulley, 5... Heating means, 7... Furnace, 8... Processing liquid, 9... Hot air supply means.

Claims (1)

[Claims] 1. A method for manufacturing an endless metal conveyor belt, comprising: 0.07 wt.% or less of C, 0.03 wt.% or less of N, 0.5 to 0.5 wt.
2.5wt.% Si, 4.0wt.% or less Mn, 5.0~9.0wt.%
Ni, 12.0~17.0wt.% Cr, 0.5~2.5wt.%
Cu, 0.2 to 1.0wt.% Ti, 1.0wt.% or less Al, provided that the A value according to the following formula is less than 41.0, A = 17 × (Cwt.%/Tiwt.%) + 0.70 × (Mnwt. %)＋1×(Niw
t.%) + 0.60 x (Crwt.%) + 0.76 x (Cuwt.%) - 0.63 x (Alwt.%) + 20.871 Stainless steel with the balance being Fe and impurity elements inevitably mixed in during manufacturing. The sheet or strip is solution-treated in the process of manufacturing the sheet or strip, and optionally subsequently temper-rolled at a rolling reduction of less than 50% to reduce the structure of the steel to substantially martensitic. The obtained sheet or strip having a substantially martensitic structure is cut into a predetermined size, and the ends of the cut sheets or strips are joined by welding to form an endless belt of a predetermined size. A method for manufacturing a metal conveyor belt, which comprises forming a metal conveyor belt, and subjecting the entire obtained endless belt to an aging treatment. 2. The method for manufacturing an endless metal belt according to claim 1, wherein the solution treatment includes an annealing treatment after cold rolling. 3. Solution treatment is applied to sheets or strips of 900
A method for manufacturing an endless metal belt according to claim 1, which comprises heating to a temperature of ~1050°C and then cooling in air or water. 4 Aging treatment is performed at a temperature range of 425-550℃ for 10-300℃.
A method for manufacturing an endless metal belt according to claim 1, which is a treatment of holding for a minute.