US2056175A - Method of heat treatment in carbonaceous atmospheres - Google Patents
Method of heat treatment in carbonaceous atmospheres Download PDFInfo
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- US2056175A US2056175A US696020A US69602033A US2056175A US 2056175 A US2056175 A US 2056175A US 696020 A US696020 A US 696020A US 69602033 A US69602033 A US 69602033A US 2056175 A US2056175 A US 2056175A
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- Prior art keywords
- carburizing
- oxygen
- carbon
- carbonaceous
- compounds
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- 238000000034 method Methods 0.000 title description 17
- 238000010438 heat treatment Methods 0.000 title description 12
- 238000005255 carburizing Methods 0.000 description 31
- 150000001875 compounds Chemical class 0.000 description 31
- 239000000203 mixture Substances 0.000 description 27
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 24
- 239000001301 oxygen Substances 0.000 description 24
- 229910052760 oxygen Inorganic materials 0.000 description 24
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 22
- 229910052799 carbon Inorganic materials 0.000 description 20
- 229910052751 metal Inorganic materials 0.000 description 20
- 239000002184 metal Substances 0.000 description 20
- 239000004071 soot Substances 0.000 description 13
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 12
- 239000007789 gas Substances 0.000 description 11
- 239000001257 hydrogen Substances 0.000 description 10
- 229910052739 hydrogen Inorganic materials 0.000 description 10
- 230000015556 catabolic process Effects 0.000 description 9
- 239000007788 liquid Substances 0.000 description 9
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 9
- 125000004432 carbon atom Chemical group C* 0.000 description 8
- 239000001760 fusel oil Substances 0.000 description 8
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 6
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 6
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 6
- 229910002091 carbon monoxide Inorganic materials 0.000 description 6
- 239000003575 carbonaceous material Substances 0.000 description 6
- HYBBIBNJHNGZAN-UHFFFAOYSA-N furfural Chemical compound O=CC1=CC=CO1 HYBBIBNJHNGZAN-UHFFFAOYSA-N 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 125000004429 atom Chemical group 0.000 description 5
- 150000002431 hydrogen Chemical class 0.000 description 5
- 125000004430 oxygen atom Chemical group O* 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- XXJWXESWEXIICW-UHFFFAOYSA-N diethylene glycol monoethyl ether Chemical compound CCOCCOCCO XXJWXESWEXIICW-UHFFFAOYSA-N 0.000 description 4
- 229940075557 diethylene glycol monoethyl ether Drugs 0.000 description 4
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 4
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 description 3
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 description 3
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 description 3
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 3
- 239000005642 Oleic acid Substances 0.000 description 3
- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-UHFFFAOYSA-N 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- PHTQWCKDNZKARW-UHFFFAOYSA-N isoamylol Chemical compound CC(C)CCO PHTQWCKDNZKARW-UHFFFAOYSA-N 0.000 description 3
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-UHFFFAOYSA-N 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid Chemical compound CCCCCCCC\C=C/CCCCCCCC(O)=O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- AMQJEAYHLZJPGS-UHFFFAOYSA-N N-Pentanol Chemical group CCCCCO AMQJEAYHLZJPGS-UHFFFAOYSA-N 0.000 description 2
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 2
- 239000001273 butane Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 229940093499 ethyl acetate Drugs 0.000 description 2
- 235000019439 ethyl acetate Nutrition 0.000 description 2
- IPCSVZSSVZVIGE-UHFFFAOYSA-N hexadecanoic acid Chemical compound CCCCCCCCCCCCCCCC(O)=O IPCSVZSSVZVIGE-UHFFFAOYSA-N 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 2
- LQNUZADURLCDLV-UHFFFAOYSA-N nitrobenzene Chemical compound [O-][N+](=O)C1=CC=CC=C1 LQNUZADURLCDLV-UHFFFAOYSA-N 0.000 description 2
- 238000006116 polymerization reaction Methods 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- RTBFRGCFXZNCOE-UHFFFAOYSA-N 1-methylsulfonylpiperidin-4-one Chemical compound CS(=O)(=O)N1CCC(=O)CC1 RTBFRGCFXZNCOE-UHFFFAOYSA-N 0.000 description 1
- ZNQVEEAIQZEUHB-UHFFFAOYSA-N 2-ethoxyethanol Chemical compound CCOCCO ZNQVEEAIQZEUHB-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 238000006711 Chan reduction reaction Methods 0.000 description 1
- 239000004386 Erythritol Substances 0.000 description 1
- UNXHWFMMPAWVPI-UHFFFAOYSA-N Erythritol Natural products OCC(O)C(O)CO UNXHWFMMPAWVPI-UHFFFAOYSA-N 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- OYHQOLUKZRVURQ-HZJYTTRNSA-N Linoleic acid Chemical compound CCCCC\C=C/C\C=C/CCCCCCCC(O)=O OYHQOLUKZRVURQ-HZJYTTRNSA-N 0.000 description 1
- 235000021314 Palmitic acid Nutrition 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- 230000001464 adherent effect Effects 0.000 description 1
- JFCQEDHGNNZCLN-UHFFFAOYSA-N anhydrous glutaric acid Natural products OC(=O)CCCC(O)=O JFCQEDHGNNZCLN-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- LDHQCZJRKDOVOX-NSCUHMNNSA-N crotonic acid Chemical compound C\C=C\C(O)=O LDHQCZJRKDOVOX-NSCUHMNNSA-N 0.000 description 1
- 150000001923 cyclic compounds Chemical class 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- UNXHWFMMPAWVPI-ZXZARUISSA-N erythritol Chemical compound OC[C@H](O)[C@H](O)CO UNXHWFMMPAWVPI-ZXZARUISSA-N 0.000 description 1
- 229940009714 erythritol Drugs 0.000 description 1
- 235000019414 erythritol Nutrition 0.000 description 1
- UKFXDFUAPNAMPJ-UHFFFAOYSA-N ethylmalonic acid Chemical compound CCC(C(O)=O)C(O)=O UKFXDFUAPNAMPJ-UHFFFAOYSA-N 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 229960004232 linoleic acid Drugs 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- WQEPLUUGTLDZJY-UHFFFAOYSA-N n-Pentadecanoic acid Natural products CCCCCCCCCCCCCCC(O)=O WQEPLUUGTLDZJY-UHFFFAOYSA-N 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- CXWXQJXEFPUFDZ-UHFFFAOYSA-N tetralin Chemical compound C1=CC=C2CCCCC2=C1 CXWXQJXEFPUFDZ-UHFFFAOYSA-N 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
- LDHQCZJRKDOVOX-UHFFFAOYSA-N trans-crotonic acid Natural products CC=CC(O)=O LDHQCZJRKDOVOX-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- C23C8/08—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 only one element being applied
- C23C8/20—Carburising
- C23C8/22—Carburising of ferrous surfaces
-
- 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
- C21D1/76—Adjusting the composition of the atmosphere
Definitions
- Our invention relates to a method of heattreatment of iron, steel, and the like, in a carbonaceous atmosphere.
- the heat treatment may be rapid, without substantial deposit on the work or within the treating system of soot, or of tarry or hard carbonaceous material.
- the apparatus for mixing. is expensive, difiicult to adjust, and will not maintain the critical ratio of gas and air without frequent readjustment. If too much air, or oxygen in other form, is added, the carburizing efiiciency is low, whereas, if too little air is added, soot is deposited. Aside from the difficulty of obtaining the correct proportions of the gases, there is always present the danger of the proportions becoming such that the mixture is explosive;
- Liquid compounds such as benzene and tetrahydronaphthalene, used in carburizing prior to our invention, have also proved unsatisfactory. In general, their use has resulted in heavy deposits of carbon or tar on the work which, in 5 some cases, is so tenacious as to require sandblasting for removal. In addition, the deposited coating is usually so impervious to the carburizing gas that the work is poorly carburized, due to scant and non-uniform transfer of carbon to 10 the work. Theoretically, it would appear that these compounds would afford a high concentration of nascent carbon, but such is not actually the case as their pyrolytic decompositionis not a simple one. On the contrary, the products of 15 decomposition of such compounds polymerize, as evidenced by the formation of naphthalene and tar during the carburizing process.
- Fusel oil a mixture of iso-butylcarbinol, having the molecular formula has proved satisfactory, aflording rapid carburization and freedom from tarry deposits or excess soot.
- the molecule of each of these compounds contains oxygen.
- the products of the pyrolytic breakdown of fusel oil and of the other compounds selected in accordance with our invention are substantially solely the gases carbon monoxide, methane and hydrogen.
- the oxygen combines in the last stage of the pyrolytic breakdown of the fusel oil with the carbon (which latter would otherwise be deposited as soot) forming carbon monoxide which, in turn, yields nascent carbon which enters into the carburizing reaction, the carbon combining with or going into the iron or steel under treatment.
- the liberated oxygen combines with another carbon monoxide molecule, forming carbon dioxide which, in turn, reacts with any carbon that may have been deposited on the Work, again forming carbon monoxide, so keeping the surface 'of the metal clean and receptive to carburizing.
- benzene whose molecular formula is We have found that cyclic compounds, when having an uninterrupted loop of carbon atoms in series, are unsuited for jcarburizing because they polymerize, forming tarry compounds which are deposited on the work and preclude satisfactory caburizing.
- our carburizing agent consists of a compound, or mixture of compounds, of oxygen, carbon and hydrogen whose molecule has a ring sequence, or a chain sequence, of carbon atoms not more than five in number unless interrupted or bridged, as in furfural, by at least one oxygen atom.
- the carburlzing compound should be liquid at ordinary room temperatures, at atmospheric'pressura'because of the greater sin!- plicity of controlling the rate of feed.
- the carburlzing compound should be liquid at ordinary room temperatures, at atmospheric'pressura'because of the greater sin!- plicity of controlling the rate of feed.
- citric acid many solids as citric acid, crotonic acid, ethyl malonic acid, glutaric acid, maleic acid, etc., come a hydrocarbon, lacking or deficient in oxygen,-
- a compound of oxygen, carbon and hydrogen for example, hexane and/or pentane; whose molecules contain no oxygen, may be mixed with erythritol and/or glycerol to form a suitable carburizing mixture, liquid under atmospheric conditions.
- fusel oil carbitol or diethyleneglycol because of their cheapness, low vapor pressure, low boiling point, and high flash temperature.
- the'vapor pressure of the liquid selected should not materially exceed about mm. of mercury at 20", nor should the flash point be less than about 100 C. Otherwise, there is some danger from inflammable vapors external to the furnace.
- furnaces While various types of furnaces may be used for carburizing or heat-treating metals by compounds of the class comprised by our invention, it is preferable or desirable to use a furnace of the type in which the carbonaceous atmosphere is forcibly circulated and forcibly stirred in contact with the work, as by a fan.
- the carbonaceous liquid is fed to a furnace passage or chamber in the form of fine mist or spray at suitably high pressure, for example, of the order of 2500 pounds per square inch, as by an atomiz'ing nozzle.
- the temperature in accordance with usual practice, is maintained at about 1700 F.
- nitrobenzene or bone oil produces excessive deposits on the surface of the work and in the furnace, and we hereby disclaim their use for carburizing or heat-treatment.
- the method of heat-treating metal which comprises heating the metal in a chamber to heat-treating temperature, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous products of definite compositions, and providing said products in said atmosphere by pyrolytically breaking. down a compound, or mixture of compounds, consisting of stoichiometric composition of carbon, oxygen and hydrogen, characterized by a sequence of carbon atoms-not more than five in number unless bridged or interrupted by an atom of oxygen,
- the method of carburizing metal which comprises heating the metal in a chamber to carburizing temperature, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous products of definite compositions,
- the method of carburizing metal which comprises heating the metal in a chamber to'carburizing temperature, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous products of definite compositions, and providing said products in said chamber by pyrolytically breaking down a mixture of isobutylcarbinol and secondary butylcarbinol.
- the method of carburizing metal which comprises heating the metal in a chamber to carburizing temperature, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous products of definite compositions,
- the method of carburizing metal which comprises heating the metal in a chamber to carburizing temperature, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous products of definite compositions,
- the method of heat-treating metal which comprises heating the metal in a chamber, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous prodnets of definite compositions, and providing said products in said chamber by pyrolytically breaking down a compound, or mixture of compounds, selected from the group consisting of fusel oil, diethyleneglycol, diethyleneglycolmonoethylether,
Description
Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE DIETHOD OF HEAT TREATMENT IN CARBONACEOUS ATMOSPHERES Pennsylvania No Drawing.
10 Claims.
. Our invention relates to a method of heattreatment of iron, steel, and the like, in a carbonaceous atmosphere.
In accordance with our invention at elevated temperature, is in contact in a chamber with an atmosphere consisting substantially of the gaseous products carbon monoxide, methane and hydrogen derived from a compound, or mixture of compounds, consisting of those stoichiometric compositions of carbon, oxygen and hydrogen, preferably liquid at usual atmospheric temperatures and pressures, which have the here inafter described relations of carbon atoms to oxygen atoms, and which by pyrolytic breakdown yield the aforesaid gaseous products.
In accordance with our method the heat treatment may be rapid, without substantial deposit on the work or within the treating system of soot, or of tarry or hard carbonaceous material.
Our invention further resides in the methods having the characteristics and features hereinafter described and claimed.
Carburizing with compounds such as methane (CH4), ethane -(CH3CH3*), propane (CH 3CH2CH3) butane, and their derivatives, is unsatisfactory because of excessive deposit of soot, orfree carbon, on the work. Attempts have been made to overcome this disadvantage by mixing air with these gases but, in practice, it has been found dificult to obtain and maintain the proper proportions. The apparatus for mixing. is expensive, difiicult to adjust, and will not maintain the critical ratio of gas and air without frequent readjustment. If too much air, or oxygen in other form, is added, the carburizing efiiciency is low, whereas, if too little air is added, soot is deposited. Aside from the difficulty of obtaining the correct proportions of the gases, there is always present the danger of the proportions becoming such that the mixture is explosive;
the metal, 7
Application October 31, 1933, Serial No. 696,020
Liquid compounds, such as benzene and tetrahydronaphthalene, used in carburizing prior to our invention, have also proved unsatisfactory. In general, their use has resulted in heavy deposits of carbon or tar on the work which, in 5 some cases, is so tenacious as to require sandblasting for removal. In addition, the deposited coating is usually so impervious to the carburizing gas that the work is poorly carburized, due to scant and non-uniform transfer of carbon to 10 the work. Theoretically, it would appear that these compounds would afford a high concentration of nascent carbon, but such is not actually the case as their pyrolytic decompositionis not a simple one. On the contrary, the products of 15 decomposition of such compounds polymerize, as evidenced by the formation of naphthalene and tar during the carburizing process.
After extensive research, we have found that high carburizing eificiency and freedom from 20 hard or tarry deposits is readily obtainable by using hydrocarbon compounds which contain oxygen and, provided that if in the molecule there are more than five carbon atoms, there shall not be more than five carbon atoms in series unless interrupted or bridged by an oxygen atom.
Fusel oil, a mixture of iso-butylcarbinol, having the molecular formula has proved satisfactory, aflording rapid carburization and freedom from tarry deposits or excess soot. As shown by their formulae, the molecule of each of these compounds contains oxygen. The products of the pyrolytic breakdown of fusel oil and of the other compounds selected in accordance with our invention are substantially solely the gases carbon monoxide, methane and hydrogen. Presumably, the oxygen combines in the last stage of the pyrolytic breakdown of the fusel oil with the carbon (which latter would otherwise be deposited as soot) forming carbon monoxide which, in turn, yields nascent carbon which enters into the carburizing reaction, the carbon combining with or going into the iron or steel under treatment. The liberated oxygen combines with another carbon monoxide molecule, forming carbon dioxide which, in turn, reacts with any carbon that may have been deposited on the Work, again forming carbon monoxide, so keeping the surface 'of the metal clean and receptive to carburizing.
Since the oxygen is in the molecule of the components of the carburizing mixture, its proportion is definitely fixed by chemical laws, or
stoichiometrically, avoiding the difficulty, en-
countered in gas carburizing with propane, butane, or the like, of need continuously to add the proper amount of air or oxygen and, in accordance with our invention, polymerization does not .HHHHHHHHHHHHHHHHH A A A A A A A A Though both fusel oil and oleic acid contain oxygen, fusel oil, made up of short carbon chain compounds, is well suited. for our carburizing method, whereas oleic acid, having a long carbon chain uninterrupted by one or more atoms of oxygen, lacks the advantages of our materials. Use of oleic acid, as above stated, results in formation of heavy carbon cake on the work. In addition, its time of pyrolytic breakdown is too slow. It is necessary or desirable that the carburizing gas be rapidly circulated or forcibly stirred for efficient and uniform carbirrizing. It is, therefore, quite essential, fronina practical standpoint, to utilize the compound whose time of pyrolytic breakdown is short. Linolic acid (CmHazOz) and palmitic acid (C1eH32O2) are also unsuited because having long carbon chans uninterrupted by an oxygen atom.
Diethyleneglycol, ethylacetate and ethyleneglycolmonoethylether, which are liquids at atmospheric pressure and ordinary temperatures, we
have also found to be well suited for carburizing;
all contain oxygen, ensuring freedom from excessive soot deposits. The molecular formulae for these compounds are I Diethyleneglycolmonoethylether, commercially known as Carbitol, a liquid at ordinary atmospheric pressure and temperature, has also been found well suited for carburizing. As shown by molecular formula,
from the closed chain or cyclic type, such as, for
example, benzene, whose molecular formula is We have found that cyclic compounds, when having an uninterrupted loop of carbon atoms in series, are unsuited for jcarburizing because they polymerize, forming tarry compounds which are deposited on the work and preclude satisfactory caburizing. When, however, there is at least one atom of oxygen included in the closed chain, as in furfural, whose molecular formula is polymerization does not occurand the oxygen prevents excess deposit of soot during pyrolytic breakdown.
In general, we have found that'superior carburizing, characterized by rapid reaction of the carburizing gases withthe metal, and freedom from formation on the work of excessive soot and/or coke, hard, caked carbon or tarry deposits, can be effected by using compounds of oxygen, carbon, and hydrogen with not more than five carbon atoms in an open or closed chain, unless bridged or interrupted by an oxygenatom. The foregoing compounds have been selected as representative of this class.v a
In general, our carburizing agent consists of a compound, or mixture of compounds, of oxygen, carbon and hydrogen whose molecule has a ring sequence, or a chain sequence, of carbon atoms not more than five in number unless interrupted or bridged, as in furfural, by at least one oxygen atom.
Preferably, the carburlzing compound should be liquid at ordinary room temperatures, at atmospheric'pressura'because of the greater sin!- plicity of controlling the rate of feed. However,
many solids as citric acid, crotonic acid, ethyl malonic acid, glutaric acid, maleic acid, etc., come a hydrocarbon, lacking or deficient in oxygen,-
with a compound of oxygen, carbon and hydrogen; for example, hexane and/or pentane; whose molecules contain no oxygen, may be mixed with erythritol and/or glycerol to form a suitable carburizing mixture, liquid under atmospheric conditions.
We prefer, however, to use fusel oil, carbitol or diethyleneglycol because of their cheapness, low vapor pressure, low boiling point, and high flash temperature. In general, the'vapor pressure of the liquid selected should not materially exceed about mm. of mercury at 20", nor should the flash point be less than about 100 C. Otherwise, there is some danger from inflammable vapors external to the furnace.
While various types of furnaces may be used for carburizing or heat-treating metals by compounds of the class comprised by our invention, it is preferable or desirable to use a furnace of the type in which the carbonaceous atmosphere is forcibly circulated and forcibly stirred in contact with the work, as by a fan.
Preferably, the carbonaceous liquid is fed to a furnace passage or chamber in the form of fine mist or spray at suitably high pressure, for example, of the order of 2500 pounds per square inch, as by an atomiz'ing nozzle.
For carburizing the temperature, in accordance with usual practice, is maintained at about 1700 F.
By use of compounds of the character specified, there are no substantial deposits of soot, or of hard or tarry carbonaceous materials, either upon the work or upon the interior structure of the furnace exposed to the carbonaceous atmosphere.
By way of illustration, the procedure and results of a typical run are briefly given. About 150 pounds of cylindrical specimens of S. A. E. 1020 steel, 7 inch in diameter and 6 inches long were disposed haphazard in the work-container of a carburizing furnace of the type in which the carbonaceous atmosphere is forcibly stirred in contact with the work and circulated by a fan. The temperature was maintained at 1700 F. After a preliminary furnace-flushing period of about fifty minutes, the carburizing agent, fusel oil, was fed as liquid at the rate of 450 cubic centimeters per hour for two hours. The results were as follows:
Case Depthin inches Hyper-eutectoid 0.012
utectoid 0.009
Hypo-eutectoid 0. 009
Total 0. 030
On removal of the specimens, there was no deposit of carbon or soot, or other carbonaceous material adherent to or caked upon any of them.
Use of nitrobenzene or bone oil produces excessive deposits on the surface of the work and in the furnace, and we hereby disclaim their use for carburizing or heat-treatment.
What we claim is:
1. The method of heat-treating metal which comprises heating the metalin a chamber to heat-treating temperature, providing in said chamber a carbonaceous'atmosphere consisting substantially of the gaseous products carbon monoxide, methane and hydrogen, and providing said products in said atmosphere by pyrolytical- 1y breaking down a compound, or mixture of compounds, consisting of stoichiometric composition of carbon, oxygen and hydrogen, characterized by a sequence of carbon atoms not more than five in number unless bridged or interrupted by an atom of oxygen, and which when pyrolytically broken down to effect the aforesaid gaseous products yields substantially no deposit of soot or of tarry or hard carbonaceous material.
2. The method of heat-treating metal which comprises heating the metal in a chamber to heat-treating temperature, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous products of definite compositions, and providing said products in said atmosphere by pyrolytically breaking. down a compound, or mixture of compounds, consisting of stoichiometric composition of carbon, oxygen and hydrogen, characterized by a sequence of carbon atoms-not more than five in number unless bridged or interrupted by an atom of oxygen,
and which when pyrolytically broken down to effect the aforesaid gaseous products of definite compositions yields substantially no deposit of soot or of tarry or hard carbonaceous material.
3. The method of carburizing metal which comprises heating the metal in a chamber to carburizing temperature, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous products of definite compositions,
and providing said products in said atmosphere bypyrolytically breaking down a compound, or mixture of compounds, consisting of stoichiometric composition of oxygen, carbon and hydrogen, characterized by a sequence of carbon atoms not more than five in number unless bridged or interrupted by an atom of oxygen, and which when pyrolytically broken down to effect the aforesaid gaseous products of definite composition yields substantially no deposit of soot or of tarry or hard carbonaceous material.
4. The method of carburizing metal which comprises heating the metal in a chamber to'carburizing temperature, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous products of definite compositions, and providing said products in said chamber by pyrolytically breaking down a mixture of isobutylcarbinol and secondary butylcarbinol.
5. The method of carburizing metal which comprises heating the metal in a chamber to carburizing temperature, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous products of definite compositions,
and providing said products in said chamber by pyrolytically breaking down the compound diethyleneglycol.
6. The method of carburizing metal which comprises heating the metal in a chamber to carburizing temperature, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous products of definite compositions,
.and providing said products in said chamber by pyrolytically breaking down the compound diethyleneglycolmonoethylether.
7. The method of heat-treating metal which comprises heating the metal in a chamber, providing in said chamber a carbonaceous atmosphere consisting substantially of gaseous prodnets of definite compositions, and providing said products in said chamber by pyrolytically breaking down a compound, or mixture of compounds, selected from the group consisting of fusel oil, diethyleneglycol, diethyleneglycolmonoethylether,
furfural.
8. In the art of heat-treating metal at elevated temperature in the presence of a carbonaceous atmosphere, the method which comprises constituting the atmosphere substantially of those gases of definite composition resulting from pyrolytic breakdown of a mixture of isobutylcarbinol and'secondary butylcarbinol.
s 9. In the art of heat-treating metal at elevated temperature in the presence of a carbonaceous atmosphere, the method which comprises constitutethyleneglycolmonoethylether, ethyl acetate, and
ing the atmosphere substantially of those gases of definite composition resulting from pyrolytic breakdown of the compound diethyieneglycol.
10. In the art of heat-treating metal at elevated temperature in the presence of a carbonaceous atmosphere, the method which comprises constituting the atmosphere substantially of those gases of definite composition resulting from pyrolytic breakdown of the compound diethyleneglycolmonoethylether.
FRITZ EBERLE.
\ CRANDALL Z. ROSECRANS.
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US696020A US2056175A (en) | 1933-10-31 | 1933-10-31 | Method of heat treatment in carbonaceous atmospheres |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3928460A (en) * | 1972-05-18 | 1975-12-23 | Basf Ag | Production of combustion gas to heat silver catalyst |
US4632707A (en) * | 1985-04-09 | 1986-12-30 | Air Products And Chemicals, Inc. | Protective atmosphere process for annealing and/or hardening ferrous metals |
-
1933
- 1933-10-31 US US696020A patent/US2056175A/en not_active Expired - Lifetime
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3928460A (en) * | 1972-05-18 | 1975-12-23 | Basf Ag | Production of combustion gas to heat silver catalyst |
US4632707A (en) * | 1985-04-09 | 1986-12-30 | Air Products And Chemicals, Inc. | Protective atmosphere process for annealing and/or hardening ferrous metals |
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