JP2007092116A - Ferromagnetic net - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ferromagnetic net which can be used as a belt of a net conveyor or a sieve for separation or classification, has superior ferromagnetism and fatigue resistance, and has enhanced corrosion resistance to an alkaline solution. <P>SOLUTION: A stainless steel wire for the net comprises at least one element among, by mass%, 0.03% or less of C, 3.0-5.0% of Si, 1.5-3.0% of Mn, 8.2-12.0% of Ni, 15.0% or more but less than 20.0% of Cr, more than 1.0% but 3.0% or less of Mo, 1.0-3.0% of Cu and 0.1-0.5% of Nb, and the balance Fe with unavoidable impurities; and includes two phases of a ferrite phase in which fibrous ferrites with a width of 10 μm or less or fine granular ferrites are interspersed at an area rate of 55 to 85% per unit area in a section of an axial direction, and an austenite phase. The ferromagnetic net has a net shape formed by using the two-phase stainless steel wire, and is used for the belt of the net conveyor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention can be used as a belt for a net conveyor for conveyance during heating, cooling, freezing, washing, etc., or as a sieve for separating and classifying powders in the process of processing foods and pharmaceuticals, The present invention also relates to a ferromagnetic network having excellent ferromagnetism and fatigue resistance and enhanced corrosion resistance against an alkaline solution.

  Conventionally, in the food and pharmaceutical industries, sieves for powder material classification and sorting, separation of foreign substances, etc., and various processed products are transported, and processing such as heating, cooling, freezing and washing is performed continuously. As a member of an automatic line device for this purpose, a metal wire net is used as a belt for a net conveyor.

  For these separation and classification screen meshes or net conveyor belts, the materials and weaving configurations are selected according to the properties, characteristics, or processing method of the powder to be treated. For example, for the former sieve As the wire mesh, for example, a metal wire that is plain or twilled so as to have a desired mesh opening, and as the latter belt, a plurality of molded products obtained by bending a predetermined metal wire or belt material into a spiral shape or a crank shape. A metal net that is formed by continuously connecting the two is used.

  These nets have different configurations and forms depending on their purposes, but they are usually used from the viewpoint of fatigue breakage due to shocks and micro-vibrations generated by processing operations, wear on the workpiece and corrosion resistance. Stainless steel wires such as SUS304 and SUS316, which have high strength and excellent corrosion resistance, are used, and have been established as general materials for network bodies today.

  However, today's social environment requires an absolute guarantee for the quality of products. In the field of processed products, especially in the fields of pharmaceuticals and foods, a part of them is missing and the processed products (products) are not. Since it is a problem directly related to human life, there is a need for a higher quality and longer life net member.

  As a measure to solve such a problem, even if a part of it falls off and is mixed in the processed product, it is detected by a magnetic separator in the next process or removed by adsorption. For example, a wire mesh for sieving It has been proposed to use a magnetic material for the wire constituting the wire (for example, Patent Document 1). In this Patent Document 1, C: 0.01 to 0.05%, Si: 0.1 to 1.5%, Mn: 0.3 to 1.0%, Ni: 3 to 8%, Cr: 20 to A high corrosion resistance stainless steel wire containing 30%, Mo: 1.0 to 6.0%, remaining: Fe and inevitable impurities is used.

  In addition, as a magnetic wire mesh for sieving, a low C high Si system containing Ni: 5-8%, Cr: 15-20%, C ≦ 0.03%, Si: 2.0-5.0% A magnetic wire mesh for screening using a duplex stainless steel wire having a two-phase structure of an austenite phase and a ferrite phase has also been proposed, for example, in Patent Document 2.

Furthermore, for example, Patent Document 3 proposes the following two types of stainless steel wires A) and B) for a belt for a net conveyor.
A) Ni: 2.5 to 8%, Cr: 18 to 30%, Mo: 3.5% or less, N: 0 to 0.2%, and one or more of Cu, Ti, Nb Duplex stainless steel containing 0 to 1% in total.
B) Cr: 17% or more, Mo: 0 to 3%, C: 0.02% or less, N ≦ 0.02%, C + N ≦ 0.05%, and one or two of Cu, Ti and Nb Ferritic stainless steel containing 0 to 1% in total.

: JP-A-10-130788 : JP 2004-332109 A : JP 2002-120919

  By the way, when producing these magnetic nets for sieving, from the viewpoint of achieving uniform workability and network quality, for example, a soft wire subjected to solution heat treatment is used, and its strength is not sufficient. Further improvement in characteristics is desired in terms of the reduction of life due to changes in the mesh due to use and fatigue failure.

  In the above proposal, when using a duplex stainless steel having a two-phase structure of an austenite phase and a ferrite phase, for example, when used in a heat treatment process of food, the surface has strong burns and thermal corrosion. Therefore, in order to remove this, a washing treatment with a sodium hydroxide solution is usually performed. For example, a normal duplex stainless steel wire proposed by Reference 2 is inferior in corrosion resistance to the alkaline solution. There is a problem that the range of use is limited.

  The present invention is a belt for a net conveyor, or a sieve for separation / classification, which improves its resistance to fatigue and wear, prolongs the life until replacement, and fragments at the time of breakage are treated objects. As a net conveyor belt or separation / classification sieve that can be easily detected and recovered using a metal detector, etc., even when it is mixed in, and has improved corrosion resistance against sodium hydroxide and can always wash effectively It is an object to provide a ferromagnetic network to be used.

That is, the invention according to claim 1 is mass%, C ≦ 0.03%, Si: 3.0-5.0%, Mn: 1.5-3.0%, Ni: 8.2-12. 0.0%, Cr: 15.0 or more and less than 20.0%, and Mo: more than 1.0 and 3.0% or less, Cu: 1.0 to 3.0%, Nb: 0.1 to 0.5 % Of at least one kind, consisting of the balance Fe and inevitable impurities,
In addition, a two-phase stainless steel wire having a ferrite phase in which fine fibrous or granular ferrites having a width of 10 μm or less are scattered at an area ratio of 55 to 85% per unit area and an austenite phase in the axial cross section is used. It is a ferromagnetic net that is formed into a metal net and used as a belt for a net conveyor.

  Furthermore, in the invention according to claim 2, the duplex stainless steel wire has a tensile strength of 1200 to 1600 MPa and an elongation of 2 to 10%, and the wire mesh has a spiral or It is characterized by being formed by continuously joining molded bodies bent into a crank shape.

Moreover, the invention which concerns on Claim 3 is the mass%, C <= 0.03%, Si: 3.0-5.0%, Mn: 1.5-3.0%, Ni: 8.2-12 0.0%, Cr: 15.0 or more and less than 20.0%, and Mo: more than 1.0 and 3.0% or less, Cu: 1.0 to 3.0%, Nb: 0.1 to 0.5 % Of at least one kind, consisting of the balance Fe and inevitable impurities,
In addition, a two-phase stainless steel wire having a ferrite phase in which fine fibrous or granular ferrites having a width of 10 μm or less are scattered at an area ratio of 55 to 85% per unit area and an austenite phase in the axial cross section is used. This is a ferromagnetic network that is formed into a metal mesh and used as a screen for a separating / classifying device that separates and classifies separated objects and classified objects.

In the invention according to claim 4, the duplex stainless steel wire has a tensile strength of 900 to 1300 MPa and an elongation of 15 to 35%, and the wire mesh has the duplex stainless steel wire as a vertical line and a horizontal line. Further, the invention according to claim 5 is characterized in that the stainless steel wire has the following formula (A): 25.0 to 28.5%, (B): 30.0 to 35. Adjusted to 0.0%.
(A) = Ni + 0.65Cr + 0.98Mo + 1.05Mn + 0.35Si + 12.6C (B) = Cr + Ni + 3.3Mo

  The ferromagnetic network used as the belt for the net conveyor of the present invention is excellent in fatigue resistance, wear resistance, and corrosion resistance, is ferromagnetic, and has good corrosion resistance against sodium hydroxide. The ferromagnetic network used as the sieve according to the present invention is also excellent in fatigue resistance, wear resistance and corrosion resistance, and is ferromagnetic and has good corrosion resistance against sodium hydroxide. Long life is obtained in the process, it can withstand washing with sodium hydroxide, and even if the wire is dropped due to breakage, it has ferromagnetism, so it can be detected with a metal detector and efficiently recovered with a magnet Is possible. Further, by adopting the constitutions of claims 2 and 4, the strength and rigidity of the duplex stainless steel wire used as a belt for a net conveyor or as a sieve are suitable for the weaving. When the nickel equivalent (A) is set to 25.0 to 28.5% as in 5, the predetermined ferrite content is provided while suppressing transformation of austenite in the base metal into processing-induced martensite. Further, the index (B) for corrosion resistance is adjusted to 30.0 to 35.0%. This helps to improve the corrosion resistance of the wire, especially in an alkaline environment.

  The ferromagnetic network 1 according to the present invention is, for example, as a ferromagnetic network 1 of a belt 1A for a net conveyor as shown in FIG. 1 or a ferromagnetic network of a separating / classifying sieve 1B as shown in FIG. 1 can be formed. The belt 1A is a wire mesh 13 formed by using a duplex stainless steel wire 10. In the case shown in FIG. 1, the wire mesh 13 is formed of a molded body 11 ..., a connecting wire 12, and the like. Consists of. The molded body 11 is wound, for example, in a zigzag spiral in which triangles are continuous in the lateral direction, and the upper and lower folded portions 11a and 11b are provided with lateral holes 11c and 11d through which the connecting wire 12 passes in the lateral direction. Forming. The molded body 11 is arranged with the lateral holes 11d, 11c below or above the other molded body 11B positioned between the upper or lower lateral holes 11c, 11d of the molded body 11A and in the lateral direction. The connecting wire 12 is sequentially inserted into the adjacent lateral holes 11d, 11c, and so on, and the molded bodies 11 are continuously connected. The molded body 11 and the connecting wire 12 are secured to the side ends by welding or the like as appropriate.

  As shown in FIG. 3A, the belt 1A is formed by bending a long belt-shaped plate, and an upward U-shaped folded portion 11e and a downward U-shaped folded portion 11f are continuously arranged in the lateral direction. Form. Lateral holes 11g and 11h are drilled at the front ends of the upward U-shaped folded portion 11e and the downward U-shaped folded portion 11f of the molded body 11, respectively. Further, the folded portions 11f, 11e below or above the other molded body 11B are inserted between the upper or lower folded portions 11e, 11f of one molded body 11A, and the lateral holes 11g, 11h,. Further, by inserting the connecting wire 12, the wire mesh body 13 is formed in which the formed bodies 11 are continuously connected.

  In addition, as shown in FIG. 3 (B), a two-phase stainless steel wire 10 is formed with a U-shaped bent portion arranged side by side to form a crank-shaped formed body 11, and the other is formed. It can also be set as the wire net-like body 13 which connected the body 11A, 11B continuously by making it latch in order by a folding | turning part. Further, it can be formed in various types such as a chain provided on both sides and further forming a curved conveyor.

  Further, as shown in FIG. 2, the ferromagnetic mesh body 1 for sieving is composed of a wire mesh body 13 formed by plain weaving a duplex stainless steel wire 10 as vertical lines 21 and horizontal lines 22. In this embodiment, the metal mesh 13 is reinforced by reinforcing frames 23 on both side edges. The reinforcing frame 23 is formed of a reinforcing plate that is folded back with the metal mesh 13 firmly sandwiched between both side edges, and has a bent portion 23a that is folded back in a U-shape, thereby reinforcing and attaching the metal mesh 13. Easy going. The front and rear edges can also be reinforced. As the wire mesh 13 used as the sieving ferromagnetic mesh 13, various materials such as twill weave, tatami mat, knitted fabric, and crimped material can be used.

  In the duplex stainless steel wire rod 10, various specifications such as thickness, weaving configuration, mesh size, etc. are appropriately set according to the type, purpose of use, treatment conditions, etc. of the object to be treated by the wire mesh body 13. it can. For example, for separation / classification in the processing process of foods and pharmaceuticals, for example, a mesh body having a wire diameter of 0.02 to 1.6 mm and 2 to 500 mesh corresponding to the particle diameter of the powder to be processed is used. As the duplex stainless steel wire 10 used for the belt, for example, a wire having a wire diameter of about 0.6 mm to 14 mm can be used.

  The said duplex stainless steel wire 10 is the mass%, C <= 0.03%, Si: 3.0-5.0%, Mn: 1.5-3.0%, Ni: 8.2-12. 0%, Cr: 15.0 or more and less than 20.0%, Mo: more than 1.0 and 3.0% or less, Cu: 1.0 to 3.0%, Nb: 0.1 to 0.5% The material which consists of remainder Fe and an unavoidable impurity is used.

  As described above, the duplex stainless steel wire 10 is added with 3.0 to 5.0% (preferably 3.5 to 4.5%) of Si, which is a ferrite-forming element, in mass%, so that the ferrite is fine. In addition, by increasing the area ratio, ferromagnetism is provided. “Fine” means that the ferrite phase is in the form of fine fibers or granules having a width of 10 μm or less in the axial section, and increasing the area ratio means that the ferrite phase has an area ratio of 55 to 85% per unit area. To do. Further, Ni is added to the duplex stainless steel wire 10 by 8.2 to 12.0% (preferably 8.5 to 10.0%) by mass%. Thereby, in combination with other structures, the corrosion resistance to sodium hydroxide is remarkably improved as shown.

  FIG. 4 shows an axial section of the duplex stainless steel wire 10 of the ferromagnetic network 1 of the present invention as an example of the distribution state of the ferrite. This figure is a microphotograph at a magnification of 400 times, and it can be seen that it is a two-phase body consisting of a ferrite phase made of gray ferrite and an austenite phase made of white austenite. The ferrite phase extends along the longitudinal direction, and is a ferrite interspersed in fine fibrous or granular form having a width of 10 μm or less (preferably 3 μm or less, more preferably 1 μm or less), and is 55 to 55 per unit area. It can be seen that the area ratio of 85% is uniformly distributed over the entire surface. By adopting such a distribution state, as described above, the fatigue resistance, wear resistance, and magnetism of the ferromagnetic network 1 can be improved. The area ratio of the ferrite phase in the cross section is preferably 70 to 85%.

  The area ratio per unit area of the ferrite phase can be arbitrarily set within the range of 55 to 85% per unit area by selecting the components of the duplex stainless steel wire 10, the processing conditions, the manufacturing method, and the like. In addition, the measurement is performed by, for example, electrolytically corroding the measurement surface of the metal wire rod with a 10N KOH aqueous solution, and measuring the cross section directly or by image analysis using a 400 × microscope image. I decided to. The measurement is performed by measuring three arbitrary points with an area of 5 cm square in an imaging view of 400 times in an arbitrary axial cross section and obtaining an average value thereof. The area ratio of the present invention is defined by this average value.

  Further, for example, as shown in FIG. 4, the ferrite has a distributed state in which the ferrite is stretched or scattered along a certain direction, and the width dimension thereof is set to 10 μm or less. The measurement is carried out with respect to the length of the portion overlapping the ferrite on the perpendicular when an arbitrary perpendicular perpendicular to the orientation of the ferrite is drawn in the 400 times magnified photograph. For example, 20 points) are measured and indicated by the average value. In addition, by distributing fine ferrite with a directivity in the matrix phase in this way, more ferrite is uniformly present, variation in characteristics is suppressed, and wire characteristics are improved.

The amount of each element including Si and Ni described above in the present invention will be described.
C (carbon) can increase the strength, but tends to reduce the corrosion resistance by forming carbides and the like. Further, since it is a strong austenite-forming element, if it is contained in a large amount, the austenite state is stabilized and it becomes difficult to obtain a predetermined magnetism, so the object of the present invention cannot be achieved. Therefore, the upper limit is made 0.03%, more preferably 0.02% or less.

  As described above, Si (silicon) is a strong ferrite-forming element. In particular, addition of 3.0% or more increases the tensile strength, wear resistance, and elastic limit, and is also effective in improving corrosion resistance. However, if it exceeds 5.0%, the toughness is reduced. Therefore, in the present invention, it is 3.0 to 5.0%, more preferably 3.5 to 4.5%.

  Since Mn (manganese) is an austenite-forming element, it is effective in stabilizing austenite to increase corrosion resistance and lowering the transformation point, but if it is less than 1.5%, the effect cannot be obtained. If it exceeds 0.0%, not only the cost is increased, but also the workability is lowered, so the range is made 1.5 to 3.0%, more preferably 1.7 to 2.5%. To do.

  Ni (nickel) is also an austenite-forming element like Mn, and it is necessary to add 8.2% or more to provide corrosion resistance that can withstand alkaline solutions. However, if it exceeds 12.0%, the tensile strength and wear resistance are lowered, so the range is set to 8.2 to 12.0%, more preferably 8.5 to 10.0%.

  Cr (chromium) is a basic component of stainless steel, and it is at least 15.0% for improving corrosion resistance and pitting corrosion resistance, stabilizing ferrite for improving magnetic properties, and enhancing corrosion resistance in an alkaline solution. The above addition is necessary, but if it is 20.0% or more, the hardness and tensile strength are lowered, so the range is made 15.0 or more and less than 20.0%, more preferably 18.0 to 19.5%.

  In the present invention, in addition to the above elements, at least one of Mo: more than 1.0 and 3.0% or less, Cu: 1.0 to 3.0%, Nb: 0.1 to 0.5% The above is contained. All of these stabilize ferrite to increase magnetism, help strengthen the fabric, and improve corrosion resistance. In particular, the addition of Mo is effective for improving the corrosion resistance in an alkaline solution, but on the other hand, the cost is increased, so a large amount of addition is not preferred, and it should be made 1.0 to 2.5%. Moreover, Cu can increase the corrosion resistance and decrease the pitting corrosion sensitivity by making the corrosion potential noble. Preferably 1.0 to 2.0%, the effect is further improved by coexistence with the Mo. Nb is also contained in an amount of 0.1 to 0.5% for the purpose of stabilizing the ferrite, but these may be used alone or in combination of two or more thereof. In addition, iron and inevitable impurities are included as the balance other than the above.

Furthermore, among the stainless steels having the above-described compositions, it is preferable to set each value obtained by the following formula within the following range, particularly from the viewpoint of enhancing the corrosion resistance against the alkali-resistant solution. (A) = Ni + 0.65Cr + 0.98Mo + 1.05Mn + 0.35Si + 12.6C = 25.0-28.5%
(B) = Cr + Ni + 3.3Mo = 30.0-35.0%

In addition to adjusting the components (A) and (B), in order to improve the magnetic properties by increasing the amount of ferrite in the material base material, (C) is preferably satisfied.
(C) = (Ni + 30C + 0.5Mn) −0.37 (Cr + Mo + 1.5Si + 0.5Nb) = 0 to 3.0%

  Said (A) is nickel equivalent, and nickel equivalent shows the influence of each component element on austenite stability, and in particular, in the magnetic wire mesh of the present invention, it is intended to have a composite structure with ferrite. Since it is necessary to combine good weaving workability without corrosion such as mesh, corrosion resistance, wear resistance, and magnetic properties, it is possible to reduce the transformation of austenite in the base metal to work-induced martensite while suppressing the transformation of the specified ferrite. A composition with an amount is necessary, and if it is less than 25.0, its effect cannot be expected, while if it exceeds 28.5%, it is not preferable because it causes an increase in cost due to an increase in expensive component elements such as Ni. .

  Said (B) is an index about corrosion resistance, and this (B) formula can show the relation with the corrosion resistance of the wire, especially the relation of corrosion resistance in an alkaline environment. The higher the value, the better the characteristics. If it is less than 30%, the effect when used as an application of the present invention is not expected. On the other hand, if it exceeds 35%, the material price increases and the workability decreases. There is a problem of cost and workability such as incurring, and more preferably 30.0 to 33.0%.

  In addition, (C), when the value is 0 to 3.0%, for example, the amount of ferrite in the material base material is increased to easily improve the magnetic characteristics, and the width dimension of the ferrite in the cross section thereof Can be made fine. That is, when this value is increased to exceed 3%, in order to obtain 55 to 85% of the ferrite amount per unit area as described above, the processing condition setting such as the heat treatment temperature is complicated to achieve stable quality. On the other hand, when the negative value is less than 0%, the austenite is decreased, and the ferrites inside are easily bonded to form coarse linear or powdery ferrite. The proportion exposed above increases and causes corrosion resistance to decrease. More preferably, the content is 0.12 to 2.4%. Thus, by satisfying both (A), (B) to (A), (B), and (C), the structure stability, magnetic properties, and corrosion resistance are combined, and it is suitable for the above application.

  When the duplex stainless steel wire 10 is used for the separation / classification sieve ferromagnetic network 1, the tensile strength is ensured from the viewpoint of ensuring weaving workability, high opening accuracy, and opening stability. It is preferable to have 900 to 1300 MPa and an elongation of 15 to 35%. In other words, fine vibrations and impacts may be applied during separation and classification, and wire breakage is easily caused by tension load during weaving. Therefore, it is necessary to have the tensile strength and elongation as a characteristic to withstand these.

  For this reason, the temperature of the stainless steel base material having the adjusted content is adjusted after cold drawing (for example, wire drawing or cold rolling) at a processing rate of 50% or more (preferably 80 to 98%). By performing annealing (solution heat treatment) at a temperature of 800 to 1100 ° C. (preferably 900 to 1050 ° C.) for a time of about 1 second to 5 minutes, the properties are two phases with a tensile strength of 900 to 1300 MPa and an elongation of 15 to 35%. A stainless steel wire 10 is obtained.

  On the other hand, in the case of the ferromagnetic net 1 used as the belt for the net conveyor, the duplex stainless steel wire 10 may be a wire or a band as described above, and further, when the woven material is made, it is a spiral. It is necessary to receive large bending deformation by processing and processing for obtaining the crank-shaped molded body 11, and to ensure processing workability, strength to withstand the weight of the conveyed product, and resistance to temporal deformation during operation.

  For this reason, the temperature of the stainless steel base material having the adjusted content is adjusted after cold drawing (for example, wire drawing or cold rolling) at a processing rate of 50% or more (preferably 80 to 98%). After annealing (solution heat treatment) at 800 to 1100 ° C. (preferably 900 to 1050 ° C.) for about 1 second to 5 minutes, further, for example, cold drawing or cold rolling with a processing rate of 5 to 60% is performed. Apply.

  Thus, the tensile strength is 1200 to 1600 MPa and the elongation is 2 to 10%. If the tensile strength is 1200 MPa or less, a wire rod that is thicker than necessary is necessary to make up for insufficient strength, and if it exceeds 1600 MPa, workability during weaving is reduced. In addition, if the elongation is less than 2%, the material is too hard, so the probability that the wire is broken during processing increases and the yield decreases. The belt is stretched and cannot be used as it is.

  The ferromagnetic mesh body 1 used as a belt for a net conveyor and a sieve for separation / classification made of the above-mentioned duplex stainless steel wire has higher resistance to fatigue and wear than the conventionally used SUS304. . Therefore, the ferromagnetic net body 1 used as the belt and the sieve of the present invention can reduce the amount of reduction due to breakage and wear due to fatigue. As a result, it can be used for a long period of time, improving production efficiency and reducing running costs. Contribute.

  In addition, the ferromagnetic mesh body 1 is excellent in magnetism and fatigue resistance, and has improved corrosion resistance against sodium hydroxide. Therefore, it is suitable as a net for a belt for a conventional net conveyor or a sieve for separation / classification. Since it is possible to wash and remove the thermally corroded portion generated by the heat treatment as described above, it is preferable in terms of food hygiene.

Example 1
Three types of duplex stainless steel wire (soft wire) (wire diameter 0.15 mm) shown in Example materials 1 to 3 in Table 1 were prepared, and each was set in a plain weaving machine to form a 60 mesh plain weave wire mesh. Obtained. Each of the soft wires was subjected to a solution heat treatment at a temperature of 1050 ° C. after the wire drawing as a pretreatment, and a fine ferrite having a width of 0.5 μm was formed into particles in the axial section of the example material. The area ratio was 76 to 81%. The tensile strength was 1050 to 1100 MPa and the elongation was adjusted to 21 to 25%.

  As comparative example materials, samples of the comparative example materials 1 to 4 in Table 1 were prepared. The samples of these comparative example materials are those described in the above-mentioned patent documents. The comparative example material 1 is the material of the patent document 1, the comparative example material 2 is the material of the patent document 2, and the comparative example material 3 is the patent document. Comparative material 4 corresponds to SUS304 material.

(Test results)
As a ferromagnetic network for sieving, with respect to Examples and Comparative Examples, sample pieces cut out from each sample were used to evaluate fatigue resistance, wear resistance, corrosion resistance, and magnetism. .

(Evaluation of wear resistance)
Abrasion resistance is 60 kg (15 kg slant cylinder, 45 kg triangle) with a barrel grinder (vibrated by Tsukishima Kikai Co., Ltd.) and a grinding wheel (MORP 6 × 15 (oblique cylinder), MT15 × 10 (triangle)) manufactured by Morita Abrasives Co., Ltd.) Then, a sample piece (50 mm square) was put therein and polished for about 8 hours, and the reduction rate due to abrasion was determined. The results are shown in Table 2.

(Evaluation of corrosion resistance)
In order to evaluate the corrosion resistance against sodium hydroxide, the sample piece (30 mm square) was immersed in a boiled sodium hydroxide solution having a concentration of 20% for 24 hours, and the reduction rate due to corrosion was determined. The results are shown in Table 2.

(Evaluation of magnetism)
For confirmation of magnetism, a metal detector (manufacturer: Nissin Electronics Co., Ltd., model: MS-3115-25S-10) was used to measure the output voltage when a sample piece (10 mm square) was detected. The results are shown in Table 2.

(Evaluation of flexion frequency)
Using a bending test apparatus (manufactured in-house), grip both ends of the sample (10 x 120 mm), repeatedly bend with a tension of 2 kgf, a bend angle of ± 45 degrees, and a bend radius of 1.5 mm. Asked. The results are shown in Table 2.

(Example 2)
The soft wire of the duplex stainless steel having the composition of Example materials 1 and 2 in Table 1 was cold-drawn at a processing rate of 32% to obtain a wire material having a wire diameter of 1.6 mm. Its mechanical properties were a tensile strength of 1200-1500 MPa and an elongation of 4-7%. By connecting a molded body 11 formed by bending this wire into a crank shape having a U-shaped span length s of 80 mm and a width of 10 mm as shown in FIG. A belt was formed to obtain a ferromagnetic network. Comparative example products 2, 3, and 4 use comparative example materials 2, 3, and 4 shown in Table 1.

  For these belts, the results of testing the fatigue resistance test, the wear resistance test, the corrosion resistance test, and the magnetic test in accordance with the above-described ferromagnetic network for sieving are the same as those of the ferromagnetic mesh for sieving. Show. Even if the magnetic material for the sieving ferromagnetic network and the sieving ferromagnetic network are the same material, there are some fluctuations in the numerical values. I understand.

  The belt was also tested for fatigue resistance. In the fatigue resistance test, an endurance test apparatus (made in-house) was used to continuously rotate at an operating speed of 40 m / min and a tension of 48 kgf, and the time until failure was measured.

  As a result, the operation time until breakage was 70 hours for the comparative product 2, 20 hours for the comparative product 3, and 66 hours for the comparative product 4, whereas the working products 1 and 2 were 72 hours. 83 hours, which is longer than that of the comparative product.

  In addition, although the comparative example product 2 was equivalent to the example product and was good in terms of the wear resistance reduction rate, the example product 2 was excellent in the wear resistance reduction rate. The wear reduction rate of Comparative Examples 3 and 4 was 10.2 and 10.4%. As a result of the corrosion resistance test, the corrosion reduction rates of Comparative Examples 2 to 4 are 1.2%, 0.1% and 0.2% respectively (Comparative Examples 3 and 4 are lower than the actual data) However, since it is a basic problem of the present invention, it is unavoidable to make such a small difference from the difference of the components.) On the other hand, the corrosion reduction rate of the conveyor belt of the present invention is 0%, It was found that the resistance to sodium oxide was high. Further, as a result of the magnetic test, the detection voltage of the comparative product 2 was 16V, the comparative product 3 was 18V, and the comparative product 4 was 1V. It was 19 V, and it was found that the detection accuracy was high.

As is clear from these results, the ferromagnetic network used as the belt for the net conveyor of the present invention and the ferromagnetic network used as the separation / classification sieve are in terms of fatigue resistance, wear resistance, corrosion resistance, and magnetism. It has excellent performance as a whole, and helps to reduce running costs, improve production efficiency, maintain surface cleanliness by cleaning, and improve product safety.
Improves the collection accuracy of the wire.

It is a top view of the mesh body for conveyor belts by the wire shape | molded helically. It is a top view of an example of the plain weave net used for separation and classification. (A) is a top view which shows the other example of a belt, (B) is a top view which shows another example. It is sectional drawing which expands and illustrates the cross section of a duplex stainless steel wire to 400 time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ferromagnetic net | network 10 Duplex stainless steel wire 11 Forming body 12 Connecting wire 13 Metal mesh body 21 Vertical line 22 Horizontal line

Claims (5)

% By mass
C ≦ 0.03%,
Si: 3.0-5.0%,
Mn: 1.5-3.0%
Ni: 8.2 to 12.0%,
Cr: 15.0 or more and less than 20.0%,
And Mo: more than 1.0 and 3.0% or less,
Cu: 1.0-3.0%,
Nb: containing at least one of 0.1 to 0.5%,
It consists of the balance Fe and inevitable impurities,
In addition, a two-phase stainless steel wire having a ferrite phase in which fine fibrous or granular ferrites having a width of 10 μm or less are scattered at an area ratio of 55 to 85% per unit area and an austenite phase in the axial cross section is used. Ferromagnetic mesh that is formed into a metal mesh and used as a belt for a net conveyor.   The duplex stainless steel wire has a tensile strength of 1200 to 1600 MPa and an elongation of 2 to 10%, and the wire mesh is a continuous product formed by bending the duplex stainless steel wire into a spiral shape or a crank shape. The ferromagnetic network according to claim 1, wherein the ferromagnetic network is formed by joining together. % By mass, C ≦ 0.03%,
Si: 3.0-5.0%,
Mn: 1.5-3.0%
Ni: 8.2 to 12.0%,
Cr: 15.0 or more and less than 20.0%,
And Mo: more than 1.0 and 3.0% or less,
Cu: 1.0-3.0%,
Nb: containing at least one or more of 0.1 to 0.5%,
It consists of the balance Fe and inevitable impurities,
In addition, a two-phase stainless steel wire having a ferrite phase in which fine fibrous or granular ferrites having a width of 10 μm or less are scattered at an area ratio of 55 to 85% per unit area and an austenite phase in the axial cross section is used. A ferromagnetic network used as a screen for a separating / classifying device that is formed into a wire mesh and separates and classifies separated materials.   The duplex stainless steel wire has a tensile strength of 900 to 1300 MPa and an elongation of 15 to 35%, and the wire mesh is woven using the duplex stainless steel wire as a vertical line and a horizontal line. The ferromagnetic network according to claim 3. The duplex stainless steel wire is characterized in that (A) in the following formula is 25.0 to 28.5% and (B) is 30.0 to 35.0%. The ferromagnetic network according to any one of the above.
(A) = Ni + 0.65Cr + 0.98Mo + 1.05Mn + 0.35Si + 12.6C (B) = Cr + Ni + 3.3Mo