US2109711A - Gas case-hardening furnace - Google Patents

Gas case-hardening furnace Download PDF

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US2109711A
US2109711A US100054A US10005436A US2109711A US 2109711 A US2109711 A US 2109711A US 100054 A US100054 A US 100054A US 10005436 A US10005436 A US 10005436A US 2109711 A US2109711 A US 2109711A
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gas
gas case
hardening furnace
furnace
cementing
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US100054A
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Saives Leon
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/767—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material with forced gas circulation; Reheating thereof
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases

Definitions

  • An object of the invention resides in the provislon of means for ensuring rapid diflusion of the freshgases entering the furnace by' whirling the gases into the muflle chamber of 'the i'urnace.
  • Another object of the invention is to provide means onthe outside of the iurnace which will force fresh gases into the mufile, chamber in such 10 a manner that the added gases are more thdroughly mixed with the gases already i the furnace to thus obtain substantially the same temperature and* chemical composition throughout the iurnace,
  • the single figure is a transverse section of 'a muflle furnace furnished with a device for the diffusion of fresh gas.
  • the improvement relates to the gas inlets and has for eiect the rendering certain of :the diflusion of the fresh gas by energetic stirring inside the furnace.
  • This device assures uniform distribution of the chemical composition and of the temperature.
  • the characteristic of this device resides in the fact that no stirring fan is introduced into the 3 iurnace because the oonstruction ot such fans iscomplicated and the working detective; especially at high temperatures when case-hardening with ca rbon.
  • the cementing gas arrives at l into the chamber 2 which provides a housing for a centrifugal 'ran 3.
  • the fan has a radial projecting action' but there is no r'dial o'utlet in the chanber 2 40 and the gas can escape only by way of an axial cone 4 terminated by a connecting piece 4 opening at a suitable place into the cementing mume 5.
  • the gas by action of the fan receives a gyratory movement but the speed of motion in the direction of the axis ofthe fan.'is not substantially increased.
  • the shaft 6 ot the fan' which leaves the chamber 2 through a stumng box 'l is guided in bearings 8 and 9 and driven by amotor -Il by means of a flexible coupling lfl.
  • a muille chamber means for introducing cementing gas into the' muflle chamber comprising a centrifugal fan having a, gas supply communicating therej 45 with, means for' rotating the Ian, a housing'forthe fan having a downwardly extending conei shaped portion with the apex thereof communicating with said muille chamber, whereby'the gas is moved into the chanber by whirling the molecules of the same in the cone-shaped housingand ison serves;

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Furnace Details (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)

Description

Patented Mar. l, 1938 UNITED STAT'ES PATENT oFFc;
2,o9,7`- GAS CASE-HARDENING'FURNACE Leon Saives, Billancou't, -Francej'assignor to Louis Renault, Blllancourt, France Application September 9, 1936, Serial No. 100954 France July 16', 1036 V 1Claim. (crees-is 7 W The present invention relates to improvements in gas case-hardening i'urnaces.
An object of the invention resides in the provislon of means for ensuring rapid diflusion of the freshgases entering the furnace by' whirling the gases into the muflle chamber of 'the i'urnace. Another object of the invention is to provide means onthe outside of the iurnace which will force fresh gases into the mufile, chamber in such 10 a manner that the added gases are more thdroughly mixed with the gases already i the furnace to thus obtain substantially the same temperature and* chemical composition throughout the iurnace,
In order to `allow of ready comprehension of the invention, it will be -more particularly described with reference to the attached drawin in which:
The single figure is a transverse section of 'a muflle furnace furnished with a device for the diffusion of fresh gas.
The improvement relates to the gas inlets and has for eiect the rendering certain of :the diflusion of the fresh gas by energetic stirring inside the furnace.
This device assures uniform distribution of the chemical composition and of the temperature.
The characteristic of this device resides in the fact that no stirring fan is introduced into the 3 iurnace because the oonstruction ot such fans iscomplicated and the working detective; especially at high temperatures when case-hardening with ca rbon.
The drawing shows one example of construction. e
The cementing gas arrives at l into the chamber 2 which provides a housing for a centrifugal 'ran 3. The fan has a radial projecting action' but there is no r'dial o'utlet in the chanber 2 40 and the gas can escape only by way of an axial cone 4 terminated by a connecting piece 4 opening at a suitable place into the cementing mume 5. The gas by action of the fan receives a gyratory movement but the speed of motion in the direction of the axis ofthe fan.'is not substantially increased. The shaft 6 ot the fan' which leaves the chamber 2 through a stumng box 'l is guided in bearings 8 and 9 and driven by amotor -Il by means of a flexible coupling lfl. The
-5o cementing muille i is housed inthe inside' of a iurnace represented by its refractory iining fl! and insulating lining ll. The mume rests on` roller-s ll allowing its !ree expanson; The ob- ;leci-.s to be case-hardened IS are put on tables I! which 'are pushed end to end into the mume i.
' *the connecting piece 4 i I Upon entering the muflle 5,-the gas gives rise 1.',
`3 which is outside o! theurnace and remains The method of 'working is as followsz in the first place theflow ot cementing gas in 1 is adjusted to suit requirements. By reason of the rotation of the tan 3 the gas'is animatedby'an intense gyratorymovement; By 'application of the theorem of kinetic moment, and 'since thegyrat- .ing gas is confined in the cone 4, the moment oi the quantity of movement is constant, and the speed of rotation of a molecule of gas is inversely proportional to its distance from the axis of the cone.
As, the gasdescends in the cone 4 its speed 'of rotation increases andbecomes very' great in to a vortex with vertical axis which fills the. whole section of the, mome. `Moreover, in the axis of this cyclone there is produced a vacuum which sucks up the gas from below to above along the axis while the gas whirls in descending near the walls of themuflle. v
This *energetic stirring assured the ho'nogeneity of distribution of the temperature 'and of the chemical composition; even in the vicinity 'oi the gas inlet connectiom There is thus avoided the dissociation or energetic cracking to which the new cementing ga's would give rise ifit were not first diluted in' a great mass oi' gas already in equilibrium with the temperature. e
It thus results that the cmenting is much' V more constant and. more regular.
Owing to the arrangement oi' the stirring Ian cool, 'its construction is easy and its working cer- 35 tain. The therm'al eflliency 'is excellent.
Finally, the cementing is very regular andretains all its eflicacy in the concave parts and bores of the objects treated.` I
^ I claim:
In a gas case-hardening furnace a muille chamber, means for introducing cementing gas into the' muflle chamber comprisinga centrifugal fan having a, gas supply communicating therej 45 with, means for' rotating the Ian, a housing'forthe fan having a downwardly extending conei shaped portion with the apex thereof communicating with said muille chamber, whereby'the gas is moved into the chanber by whirling the molecules of the same in the cone-shaped housingand ison serves;
US100054A 1936-07-16 1936-09-09 Gas case-hardening furnace Expired - Lifetime US2109711A (en)

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FR2109711X 1936-07-16

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2438923A (en) * 1943-02-11 1948-04-06 Fed Telephone & Radio Corp Method and means for making selenium elements
US2656170A (en) * 1951-11-16 1953-10-20 Selas Corp Of America Method and apparatus for heating objects
US3245672A (en) * 1961-05-23 1966-04-12 Huettenwerk Oberhausen Ag Furnace for the heat-treatment of billets, blooms and the like

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2438923A (en) * 1943-02-11 1948-04-06 Fed Telephone & Radio Corp Method and means for making selenium elements
US2656170A (en) * 1951-11-16 1953-10-20 Selas Corp Of America Method and apparatus for heating objects
US3245672A (en) * 1961-05-23 1966-04-12 Huettenwerk Oberhausen Ag Furnace for the heat-treatment of billets, blooms and the like

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