PL200121B1 - Activator feeder used in thermochemical treatment processes of stainless steel - Google Patents

Abstract

An activator dosing device for thermochemical treatment of stainless steels, comprising a housing with a cover and an activator container, is characterized in that the tubular housing (1) contains a container (2) inside which an activator reservoir (3) is located, open at the top. The container (2) is attached to a vertical adjustment rod (7), and the tubular housing (1) ends with a flange that is releasably connected to the head flange (9) by a fastener (8). The head (9) is equipped with two openings: one opening to which a connector (11) is attached, and the other opening in the upper part of the head, located on its vertical axis, with the upper part of the head body (9) connected by a thread to an adjustment nut (12).

Description

Description of the invention

The subject of the invention is an activator dosing device in the processes of thermo-chemical treatment of stainless steels carried out in retorts for the conduct of thermo-chemical treatment processes of secretion-hardened stainless steels in gas atmospheres.

Gas nitriding, due to the possibility of processing objects with complex shapes and a large number of internal surfaces, is one of the most advantageous methods of increasing the tribological wear resistance of precipitation-hardened stainless steels used, among others, for rotors of radial compressors. During the nitriding process, the production of a nitrided layer with appropriate operational parameters requires continuous activation of the surface of an element made of precipitation-hardened stainless steel. For gas nitriding processes, usually carried out in retorts, the most appropriate method seems to be the continuous activation of the surface during the process with hydrogen chloride, resulting from the dissociation of ammonium chloride. Dosing of ammonium chloride in these processes consists in placing a certain amount of ammonium chloride in the solid state at the bottom of the retort, which, after starting the process, evaporates in the initial stage of the nitriding process. This method does not ensure a constant and continuous supply of ammonium chloride to the working space of the retort, ammonium chloride dissociates very quickly, often before reaching the temperature appropriate for the nitriding process and causes clogging of the outlet pipes.

From the patent description SU 545695 a powder chrome retort is known. In the process, the activator is ammonium halide, which is introduced into the retort chamber and remains at the process temperature without the possibility of changing this temperature. The device's retort is filled with argon and heated to the chrome-plating temperature. The front cover of the retort opens and the chrome elements are poured through it. The device (retort) tilts at an angle of 30-40 °, which causes the displacement of the chromating agent. The retort rotates in the furnace around its axis in a horizontal position. The activator is introduced via the feed line into a stationary, non-sliding container. It is known from the patent description SU 1154374 for a powder chrome retort, where the source of chromium atoms is a granulate containing chromium compounds with the addition of an activator in the form of ammonium halides. The addition of this granulate consists in filling the auxiliary chamber, and then tilting the retort by a certain angle from the horizontal position, when the granules are poured into the main chamber of the retort under the influence of gravity. Dissociation of the activator-containing granules takes place in the main chamber of the retort at a constant temperature of the chrome plating process.

An activator metering device for the thermo-chemical treatment of stainless steels according to the invention consists of a tubular housing, a container which is detachably attached to a vertical control rod. Inside the container is an activator reservoir, open at the top, in which the activator is placed. The tubular housing is detachably connected with the head flange by means of a fastener. The head is equipped with two holes, one hole to which a pipe stub for supplying the processing atmosphere is attached, and another hole in the upper part of the head, located in its vertical axis, through which the control bar is led out. The upper part of the head body is threaded with an adjusting nut. The container consists of a base, a top cover, which are circular and at least three stirrups connecting them, two of which are arranged opposite to each other in the axial plane of the container, and the others are circumferentially spaced between them. The top cover has through holes for better circulation of the activator. In another embodiment, the container is in the form of a cylinder with an open side surface. Preferably, the container has through-holes on the top cover and on the side surface for better circulation of the activator. The container is detachably attached to a vertical adjustment bar. Preferably, the container is attached to the rod by a thread or by a hook. Ammonium chloride vapors are transferred by the ammonia flowing through the head to the retort, and their partial pressure, for a constant ammonia flow rate, depends on the container temperature. The container does not have its own heating and its temperature depends on the temperature in the retort nitriding chamber and the distance between the container and the nitriding chamber. Setting the position of the container at the appropriate temperature and height is achieved by shifting the control bar in the direction of the vertical axis and securing it against changing its position by tightening the adjusting nut on the head body. The position of the container is set once during the nitriding process at a temperature that ensures adequate ammonium chloride evaporation, based on the temperature distribution in the inlet pipe, determined experimentally.

PL 200 121 B1

The device according to the invention is shown in the exemplary embodiments and in the drawings, in which fig. 1 shows the dispensing device in a vertical section, fig. 2 - detail - a container for a reservoir with an activator in a perspective view, fig. 3 - another version of a container in a perspective view. 4 - perspective view of another version of the container, Fig. 5 - perspective view of another version of the container, Fig. 6 - vertical section of the dispensing device mounted in a retort.

P r z k ł a d 1

The device consists of a tubular housing 1, a container 2 inside which a reservoir 3 of ammonium chloride is placed. The container 2 has the shape of a cylinder and consists of a base 4, a top cover 5 and three stirrups 6 connecting them, the ends of which are welded to the base 4 and the top cover 5. The two stirrups are positioned opposite to each other in the axial plane of the container 2, and the third is located between them around the perimeter. The container 2 is attached to the vertical adjustment rod 7 by means of a thread. The ammonium chloride reservoir 3 has the shape of an open cylinder. The tubular casing 1 ends with a flange, which is detachably connected with the flange of the head 9 by means of a fastener 8 and sealed with a gasket 10. The head 9 has two holes, one hole with the stub 11 for a flexible conduit supplying ammonia, the other hole is in the upper part of the head body 9 along its vertical axis. Through this second opening, the control rod 7 is led out. The head body 9 is threaded to the outside and equipped with an adjusting nut 12 and a gasket 13. Ammonium chloride vapors are transferred by ammonia flowing through the head to the retort, and their partial pressure, for a constant velocity the ammonia flow depends on the temperature of the container 2. The container 2 has no heating of its own and its temperature depends on the temperature in the retort nitriding chamber and the distance of the container 2 from the nitriding chamber. Setting the position of the container 2 at the appropriate temperature and height is achieved by shifting the control rod 7 in the direction of the vertical axis and securing it against changing its position by tightening the adjustment nut 12 on the head body 9. The container position is set once during the nitriding process at the temperature ensuring adequate evaporation of ammonium chloride, based on the temperature distribution in the inlet pipe, determined experimentally.

During the nitriding of precipitation-hardened stainless steel OH14N5CuNb in an ammonia atmosphere at 570 ° C for 6 hours, by placing the container 2 with ammonium chloride in the temperature zone of 300 ° C and flowing through the ammonia tank 3 at a rate of 40 l / h, a partial pressure of chloride is obtained ammonia of 100Pa. As a result of the action of ammonium chloride on the steel surface, the oxides on this surface are reduced, which made it possible to create a 0.1 mm thick nitrided layer.

P r z k ł a d 2

Device as in example 1, except that the container 2 has the form of a cylinder and consists of a base 4, a top cover 5 and four stirrups 6 connecting them, the ends of which are welded to the base 4 and the top cover 5. The two stirrups are arranged opposite to each other in the axial plane of the container 2, the other two being circumferentially therebetween. The top cover 5 has through-holes on its surface for better circulation of ammonium chloride vapors.

The principle of operation of the device as in example 1.

P r z k ł a d 3

Device as in example 1, except that the container 2 is in the form of a cylinder, the side surface of which is open for at least half of the circumference of its bases, and has through-holes on the top cover 5 and on the side surface for better circulation of ammonium chloride vapors. The container 2 is connected to the regulating rod 7 by means of a catch.

The principle of operation of the device as in example 1.

List of designations

1. Tubular housing

2. Container

3. Activator reservoir

4. Base of the container

5. Top cover of the container

6. Stirrups

7. Regulating rod

8. Buckle

9. Head

10. Gasket

PL 200 121 B1

11. Pipe connection for the lastical pipe

12. Seculasynna nut

13. Gasket

14. Collective retorts

15. Coverage

Claims (7)

Patent claims 1. Office for dernjącn aPrePair pore cnemicnnia cnmicnnial stainless steel newicistinc -kud-nc cover p-jcmaik as skywst-y, characterized by the fact that in yuy-wcj-kud-wic (1) starting , wcwaątyn ktcycu- umicannn-ac jcat nki-yaik (3) sktywst-ys, ktwsrtc -d gdyc, prnc nnym p-jcmaik (2) prncm-n-insac jcat e-pi-a-wcg- pręts rcuulsncjacu- (7 ), nsś rur-ws -kud-ws (1) nsk-ńnn-as jcat k-stringrncm, ktdrc jcat p-lnn-ac r-nątnaic ns pm-ną nspiasnns (8) n k-stringrncm depth-winc (9 ), prnc nncm gw-wins (9) wcp-asż-as jcat in dws -tw-rc, jcdca -twdr, d- ktCrcg- prncm-n-insert jcat kyCcicc (11), second -twdr in the improvement of the depth of So, uactu-insert in jcj -and pi-a-wcj, prnc oncm strain k-rpuau-loosen (9) p-connect-ys jcat ns pm-n uwiatu n with rcuulsotia gland (12). 2. UrząCdenie wwddjg zesta. d, with changes, j ρ ^ ΓηηίΡ p2) nnkdewópy j jsa z | npkdtapw 04), p-krcwc udracj (5) -rsn c- asj ^ ic trncoe joining jc atrncmi-a (6), n ktdrcoe dws r- nmicanon-ac aą asprnctujk- aickic w plsancncźaic -ai-wcj p-jcmaiks (2), nsś pn-atsc r-nmicancn-ac aą as -kw-dnic p-intermediate aimi. 3. UryąCdedie of the waters of desire. 1, znnmieenn the fact that ppjmηik (22 mm ppktap wwlca, kkc ^ rr ^^ o p-wicrnceais k-cnas jcat -twsrts. 4. Consumption of waters by zaptr. 4, change of mt ^ m, that ppimtik 0 ^ 2 mm on the top cover C 0 () and as p-wicrnceyi k-cnation prncl-t-wc -tw-rc. 5. UrzeCdediewódług cold. fzzamieenetym, ż ppjmηik (2) przemηkcwópyj jca depiokyr wcu- pręts rcuulsccjyc- (7) r-connectorsic. 6. UrzeCdedevo dong with me _! ż ppiąmηik (2) przemηkcwópyj jca depiokyr wcu- pręts rcuulsccjyc- (7) prnc pm-cc uwiatu. 7. UrzeCdediewódług ζ ^^ Λςzamieenatym, ż ppjąmηik (2) przemηkcwópyj jca depiokyr wcu- pręts rcuulsccjycu- (7) prnc p-m-cc nscncpu.