JPWO2014083587A1 - Manufacturing method of sinter cake support stand and overlay welding method in sinter cake support stand - Google Patents

Abstract

A process of preheating the stand material, a process of overlay welding the weld metal on each side of the side wall thinning part formed by thinning the upper edge and both side surfaces of the stand material, and an outer periphery of the thinning part A step of overlay welding the weld metal on each side along the surface, a step of overlay welding the weld metal around the entire end surface of the stand material, and a step of gradually cooling the stand material subjected to the overlay welding It is characterized by.

Description

  The present invention relates to a method for producing a sinter cake support stand (hereinafter referred to as “stand” as appropriate) used in a sinter cake support sintering method for producing a sintered ore to be used in a iron making process in an ironworks, and overlay welding in the stand. Regarding the method.

  Conventionally, in the production of sintered ore by a downward suction type sintering machine, the cross section is used as a method for improving the productivity by preventing the deterioration of the air permeability due to the sintering cake itself being compressed by its own weight. However, there is a method in which a plate-like support member (stand) having a trapezoidal shape and having a height of 200 to 400 mm is vertically arranged so as to be embedded in the raw material packed layer and arranged in parallel with the traveling direction of the sintering pallet. For example, Patent Document 1 discloses a method of improving the shape and arrangement of the stand and improving the air permeability and the excavation property.

  Patent Document 2 discloses a technique for extending the life of a stand by using special cast steel as an appropriate material for the stand.

  Further, Patent Document 3 discloses a method for further extending the life of the stand by performing wear-resistant overlay welding on the ridge line portion and / or the side surface portion of the upper blade portion of the stand.

Japanese Patent Laid-Open No. 9-4981 JP-A-9-41098 JP 2002-13876 A

  In the process of sintering the sintering raw material layer in the sintering machine pallet, as the deterioration form of the stand disposed in the sintering layer, in addition to the generation and progression of cracks due to the thermal cycle due to operation, the raw material There is corrosion and wear caused by rubbing with sintered ore in a high-temperature oxidation / sulfurization atmosphere for firing and discharging.

  However, in the method of Patent Document 3, sufficient corrosion resistance cannot be expected in the built-up portion. Moreover, it cannot be said that it has both wear resistance and corrosion resistance particularly in a high temperature atmosphere.

  Then, this invention is made | formed in view of the said subject, and it aims at providing the manufacturing method of the stand excellent in abrasion resistance and corrosion resistance also in a high temperature atmosphere, and the overlay welding method in a stand.

  In order to solve the above problems, a method for producing a sinter cake support stand according to the present invention is provided on a sintering pallet of a downward suction type sintering machine, and has a substantially trapezoidal shape that supports the sinter cake during the production of sintered ore. A sinter cake support stand comprising a main body portion and a pedestal portion for mounting on a sintered pallet, the upper edge and both side surfaces of the main body portion of a stand material having a base material of martensitic stainless cast steel Forming a thinned portion by reducing the thickness, a step of preheating the stand material at a temperature of 150 ° C. or higher, a step of overlay welding a weld metal for each side of the reduced thickness portion formed on the side surface, The process of overlay welding the weld metal on each side along the outer periphery of the thinned part, the process of overlay welding the weld metal to the entire end surface of the stand material, and the stand material subjected to overlay welding are gradually performed. Cooling process And wherein the Mukoto.

  Here, it is preferable that the welding conditions for overlay welding the weld metal are a current of 280 to 300 A, a voltage of 28 to 30 V, and a welding speed of 30 to 40 cm / min. It is more preferable to include a step of applying post-heat to the stand material after the step of overlay welding the weld metal on the entire periphery of the end surface of the stand material and before the step of gradually cooling the stand material.

  The stand manufactured in this manner is reinforced by overlay welding at the portion that comes into contact with the sinter cake, and thus has excellent wear resistance and corrosion resistance in a high temperature atmosphere. In particular, in the conventional overlaying method, a stand that uses martensitic stainless cast steel as a base material is prone to cracking of the stand, but in the present invention, the cracking of the stand is prevented by preheating, setting of overlaying conditions, and slow cooling. It is also possible to suppress the occurrence.

  Further, the present invention is provided on a sintering pallet of a downward suction type sintering machine, a substantially trapezoidal main body portion that supports a sinter cake at the time of sinter ore production, and a pedestal portion for attaching to the sintering pallet A build-up welding method in a sinter cake support stand in which a thinned portion is formed by thinning the upper edge portion and both side surfaces of a main body portion of a stand material having a base material made of martensitic stainless cast steel. , The process of overlay welding the weld metal on each side of the reduced thickness portion formed on the side surface, the process of overlay welding the weld metal on each side along the outer periphery of the reduced thickness section, and the entire end surface of the stand material And a process of overlay welding a weld metal to the weld cake welding method in the sinter cake support stand.

  In this case, it is preferable that in the step of overlay welding the weld metal on each side of the thinned portion formed on the side surface, further overlaying is performed for each row from below the thinned portion.

  According to the method for manufacturing a stand according to the present invention, the portion in contact with the sinter cake is reinforced by overlay welding, so that a stand excellent in wear resistance and corrosion resistance can be manufactured even in a high temperature atmosphere. The life of the stand can be extended by extending the replacement period.

It is a flowchart which shows the welding procedure of a stand. It is a front view which shows the stand raw material before overlay welding. It is a front view which shows the stand raw material which carried out build-up welding to the side wall thinning part. It is a front view which shows the stand raw material which carried out overlay welding to the side wall thinning part outer periphery. It is a top view which shows the stand raw material which carried out overlay welding to the end surface perimeter.

  Hereinafter, the stand manufacturing method and overlay welding method according to the present invention will be described with reference to the drawings.

  FIG. 1 is a flowchart showing a stand welding procedure, and FIG. 2 is a front view showing a stand material before overlay welding.

  The stand is a member that is mounted on the sintering pallet and supports the sinter cake in order to ensure the air permeability of the sintering raw material layer in the sintering pallet when the sintered ore is produced by the downward suction type sintering machine.

  The stand is manufactured by performing overlay welding on a stand material 1 made of martensitic stainless cast steel as a base material, and is composed of a main body portion 2 that supports a sinter cake and a pedestal portion that is attached to a pallet truck. Yes. The stand material 1 is preferably a martensite system from the viewpoint of wear resistance. However, in order to suppress cracking at a high temperature, a ferrite-type and austenite-type duplex steel material may be used, and a coin overlay layer may be formed on the surface layer.

  In manufacturing the stand, first, the stand material 1 is inspected before overlay welding is performed (step S100). In the inspection, the presence or absence of nests or cracks in the stand material 1 is confirmed by visual inspection, the presence or absence of cracks by a penetration depth test, and the presence or absence of distortion at a predetermined location.

  Moreover, the dimension of the side wall thinning part 3 formed in the main body part 2 is also confirmed. The main body 2 supports the sinter cake in order to maintain the air permeability of the lower layer of the sintering raw material layer, so that the upper edge portion that is in contact with the sinter cake, that is, the upper side portion and both oblique sides of the substantially isosceles trapezoid shape Need to be reinforced. Therefore, the side wall thinning portion 3 is formed by skin-cutting the upper edge portion and both surfaces of the main body portion 2 (front surface and back surface in FIG. 2). By welding the weld metal to the side wall thinning portion 3, the stand becomes excellent in wear resistance and corrosion resistance even in a high temperature atmosphere.

  Here, when the side wall thinning portion 3 is set to “T” mm, the weld metal is built up to a thickness of 1.5 T to 4 Tmm in the build-up welding step (step S104) to the side wall thinning portion 3 described later. It is preferable to weld. This is because if it is less than 1.5 Tmm, it is difficult to obtain an effect of wear resistance and may cause distortion, and if it exceeds 4 Tmm, the stand material 1 may be cracked.

  Note that the side wall thinning portion 3 is provided with a level difference between the left side and the right side in the figure because the sinter cake advances from the left side to the right side in the figure, so Because it is possible to increase the wear resistance and corrosion resistance of the stand by forming a step so that the build-up part on the side increases and making the build-up part on the side in contact with the sintered mass more It is.

  After the above inspection, pre-heating is applied to the stand material 1 (step S102). Preheating is performed by heating the stand material 1 at a temperature of 150 to 250 ° C. Preheating at a temperature lower than 150 ° C increases the possibility of cracking of the stand. If preheating at a temperature exceeding 250 ° C, the weld metal may become a material and the stand may be deformed. is there. Therefore, it is preferable to control the temperature by measuring the temperature of the central portion of the stand material 1 using a contact thermometer or a temperature choke so that the preheating temperature falls within the above temperature range.

  After preheating the stand material 1, build-up welding of the side wall thinning portion 3 is performed (step S104). The build-up welding of the side wall thinning portion 3 is further performed 8 to 10 times (in 8 to 10 passes) for each row from the lower side of the stand material 1, and the side wall build-up weld portion 4 as shown in FIG. Form. At this time, it is preferable to perform overlay welding by applying a copper plate to the upper portion of the stand material 1 so that the metal to be overlayed does not melt. If the build-up amount per pass is increased too much, the molten metal will fall. Moreover, when the build-up layer per pass is thinned, the crystal becomes finer and the thermal shock resistance is improved. On the other hand, too many passes will hinder productivity. Therefore, a film is formed in 8 to 10 times.

  Further, the welding heat input affects the wear resistance and corrosion resistance of the stand after manufacture. If the welding heat input is small, the effects of wear resistance and corrosion resistance cannot be expected. If the welding heat input is large, the thermal stress increases and the occurrence rate of cracks in the stand increases. Therefore, it is preferable that the welding conditions defining the welding heat input are: current: 280-300 A, voltage: 28-30 V, welding speed: 30-40 cm / min.

  The weld metal to be overlay welded is a wire in which alloy powder is packed in a tube, and welding is performed at a temperature of 500 ° C. or less during welding. The reason for setting the temperature during welding to 500 ° C. or less is to prevent softening of the built-up portion. Also in this case, it is preferable to control the temperature by measuring the temperature of the central portion of the stand material 1 using a contact thermometer or a temperature choke.

  When build-up welding of the side wall thinning portion 3 on one surface is performed, build-up welding of the side wall thinning portion 3 on the opposite surface is performed in the same procedure (step S106).

  After performing the build-up welding of the side wall thinning portions 3 on both sides, the outer circumference of the side wall thinning portion 3, that is, both oblique sides of the stand material 1 having a substantially trapezoidal shape, is built up in one layer, and FIG. As shown, the side surface peripheral welded portion 5 is formed (step S108). At this time, it is preferable to perform overlay welding by applying a copper plate to the oblique side portion of the stand material 1 so that the metal to be overlayed does not melt. Similarly, the outer periphery of the opposite side thinned portion 3 is also welded to form the side outer peripheral welded portion 5 (step S110).

  After performing build-up welding of the side wall thinning portion 3, build-up is performed on a portion that is not welded (the upper edge of the upper side of the main body 2 and the upper edge of both oblique sides), that is, the entire end surface of the stand material 1. Welding is carried out (step S112), and as shown in FIG. 5, end face build-up welds 6, 7, and 8 are formed in the order of end face build-up weld part 6, end face build-up weld part 7, end face build-up weld part 8. To do. Also at this time, overlay welding is performed by applying a copper plate to the side surface welded portion 4 or the side surface outer surface welded portion 5 that has already been welded so that the metal to be built up does not melt away. preferable.

  After the build-up welding is performed on the stand material 1 to form the side-surface build-up weld portion 4, the side surface outer-surface build-up weld portion 5 and the end-face build-up weld portions 6, 7, and 8, the post-heat is applied to the stand material 1 ( Step S114). The post-heating is performed by heating the stand material 1 after overlay welding at a temperature of 250 ° C. or higher. By performing the post-heating, the stand is not easily broken and durability can be improved. In addition, when the temperature of the stand raw material after build-up welding is 250 degreeC or more, it is good also as omitting the process of applying post-heating.

  Thereafter, the stand material 1 is gradually cooled (step S116), and the shape of the overlaid metal hanging portion is adjusted by a grinder process or the like, and the stand material 1 is inspected for cracking, distortion inspection, and overlaying. After the dimensional inspection of the place, the stand is completed.

  The stand manufactured by the procedure as described above has excellent wear resistance and corrosion resistance, and it is possible to extend the life of the stand by extending the replacement period of the stand.

  As mentioned above, although the manufacturing method of the stand which concerns on this invention, and the overlay welding method in a stand were demonstrated based on embodiment, this invention is not limited to this, The objective of this invention can be achieved and Various design changes can be made without departing from the scope of the invention, and they are all included in the scope of the present invention.

  INDUSTRIAL APPLICATION This invention can be utilized as a manufacturing method of the support stand used for the sinter cake support sintering method which manufactures the sintered ore used for the iron making process in a steelworks.

DESCRIPTION OF SYMBOLS 1 Stand material 2 Main-body part 3 Side surface thinning part 4 Side surface build-up weld part 5 Side outer periphery build-up weld part 6, 7, 8 End face build-up weld part

Claims (5)

A sinter cake support stand provided on a sintering pallet of a downward suction type sintering machine, and comprising a substantially trapezoidal main body for supporting a sinter cake during the production of sinter ore and a pedestal for attaching to the sintering pallet A manufacturing method of
Forming a thinned portion by thinning the upper edge portion and both side surfaces of the main body portion of the stand material using the martensitic stainless cast steel as a base material;
A step of preheating the stand material at a temperature of 150 ° C. or higher;
A process of overlay welding a weld metal for each side of the thinned portion formed on the side surface;
A process of overlay welding the weld metal on each side along the outer periphery of the thinned portion;
A process of overlay welding a weld metal around the entire end surface of the stand material;
And a step of slowly cooling the stand material subjected to overlay welding. A method for manufacturing a sinter cake support stand. The welding conditions for overlay welding the weld metal are as follows: current is 280 to 300 A, voltage is 28 to 30 V, and welding speed is 30 to 40 cm / min. Of manufacturing a sinter cake support stand. After the process of overlay welding weld metal to the entire circumference of the end surface of the stand material, before the process of gradually cooling the stand material,
The method for manufacturing a sinter cake support stand according to claim 1, further comprising a step of applying post-heat to the stand material. A martensite system, which is disposed on a sintering pallet of a lower suction type sintering machine and has a substantially trapezoidal main body for supporting a sinter cake during the production of sintered ore and a pedestal for attaching to the sintering pallet. It is a build-up welding method in a sinter cake support stand in which a thinned portion is formed by reducing the thickness of the upper edge and both sides of the main body of a stand material made of stainless cast steel as a base material,
A process of overlay welding a weld metal for each side of the thinned portion formed on the side surface;
A process of overlay welding the weld metal on each side along the outer periphery of the thinned portion;
A build-up welding method for a sinter cake support stand, comprising a step of overlay welding a weld metal on the entire periphery of the end surface of the stand material. In the process of overlay welding the weld metal for each side of the thinned portion formed on the side surface,
The build-up welding method for a sinter cake support stand according to claim 4, wherein the build-up is further performed for each row from below the thinned portion.

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