US2825658A - Method of chromizing - Google Patents
Method of chromizing Download PDFInfo
- Publication number
- US2825658A US2825658A US460242A US46024254A US2825658A US 2825658 A US2825658 A US 2825658A US 460242 A US460242 A US 460242A US 46024254 A US46024254 A US 46024254A US 2825658 A US2825658 A US 2825658A
- Authority
- US
- United States
- Prior art keywords
- chromizing
- chromium
- compound
- percent
- finish
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
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
- C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
- C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
- C23C10/34—Embedding in a powder mixture, i.e. pack cementation
- C23C10/36—Embedding in a powder mixture, i.e. pack cementation only one element being diffused
- C23C10/38—Chromising
- C23C10/40—Chromising of ferrous surfaces
- C23C10/42—Chromising of ferrous surfaces in the presence of volatile transport additives, e.g. halogenated substances
Definitions
- the present invention relates to chromizing "of low carbon steel usually of the order of A181 1010, but permissibly having a nominal carbon content up to and including 0.35 percent carbon.
- a purpose of the invention ' is to obtain a more smooth chromized surface on low carbon steel, with a minimum of etching and other defects.
- a further purpose is to accelerate the diffusion of chromium into low carbon steel.
- a further purpose is to minimize the sintering of the chromizing compound to the surface of low carbon steel during chromizing.
- a further purpose is to employ from 0.06 to 0.26 and preferably about 0.1 percent by weight of ammonium bromide calculated on the chromium content of the source of chromium in chromizing low carbon steel.
- a further purpose is to use between 25 and 85 percent by weight of finely divided inert'bodying'material based on the chromium content of the source of chromium in the chromizing compound.
- a further purpose is to mix one volume of the fresh chromizing compound with from 2.5 to 3.5 volumes of expended compound for chromizing.
- chromizing may be carried out using a source of chromium and a bodying agent such as raw kaolin, along with an ammonium halide as a catalyst.
- a source of chromium and a bodying agent such as raw kaolin
- an ammonium halide as a catalyst.
- the results obtained, however, are marred by the fact that the surface is considerably etched under the treatment, frequently producing discoloration, and the resultant finish is in general considerably rougher than the finish of the steel before treatment. and the advantages of chromizing from the standpoint of corrosion resistance and resistance to corrosion at elevated temperature have justified the use of chromizing.
- the process is carried out using a chromizing compound which is in contact with or mmediately adjacent to the low carbon steel For some service this result is not objectionable,
- the chromizing compound itself consists of a source of chromium in finely divided form, a catalyst and desirably an inert finely divided bodying agent.
- an inert finely divided bodying agent is desirably used. This may be for example calcined clay, calcined kaolin or calcined alumina.
- the quantity of the inert bodying agent should be '25 to percent of the weight of the chromium present.
- the source of chromium and the inert bodying agent as well as the catalyst should be finely divided, preferably through mesh per linear inch.
- the chromizing composition according to the invention may be as follows:
- One suitable procedure for chromizing is to insert the low carbon steel parts to be chromized in a closed box, packing the chromizing compound around the parts.
- the box is provided with a vent which allows the bromine, hydrogen, ammonia and nitrogen formed by the dissociation of the ammonium bromide to sweep out the air.
- the vent is suitably closed by a molten slag seal.
- the iron which is present as an impurity in the ferrochrome can be ignored in the composition since in any case iron is diffused from the steel to replace the chromium which diffuses into the steel.
- the parts chromized using the ammonium iodide catalyst had a good finish but it was marred by slight sinter ing of the chromizing compound on the parts.
- the parts chromized using ammonium chloride had a good finish, but inferior to those chromized using the iodide. ously than'in the case of the iodide.
- the finish obtained with the bromide was the best se-' cured from the standpoint of evenness, complete absence of sintering and freedom from etching of the parts treat ed. 7 n
- the normal technique is to retain the compound in the box from the'last treatment, and add to it one part by volume of new compound to 2.5 to 3.5 parts, preferably about 3 parts by volume of expended compound from previous treatments. This approximately Thepowder sintered on the surface more seriactual chromizing'mixture in piac-i compensates for the loss of compound and builds up a .proper chromizing potential in the new compound.
- the method of chromizing which comprises treating steel having a carbon content of 035 percent or less with exclusion of air at a temperature of from 1650 to 1950" F. for a time of at least three hours with a source of finely divided chromium and from.0.06 to.0.26 percent on the weight of the chromium of ammonium bromide.
Description
METHOD OF CHROMIZING George A. Samuel, Philadelphia, Pa., assignor to Metal Dilfusions, Inc., Philadelphia, Pa., a corporation of New Jersey No Drawing. Application October '4, 1954 Serial No. 460,242
4 Claims. (Cl. 117-107) The present invention relates to chromizing "of low carbon steel usually of the order of A181 1010, but permissibly having a nominal carbon content up to and including 0.35 percent carbon.
A purpose of the invention 'is to obtain a more smooth chromized surface on low carbon steel, with a minimum of etching and other defects.
A further purpose is to accelerate the diffusion of chromium into low carbon steel.
A further purpose is to minimize the sintering of the chromizing compound to the surface of low carbon steel during chromizing.
A further purpose is to employ from 0.06 to 0.26 and preferably about 0.1 percent by weight of ammonium bromide calculated on the chromium content of the source of chromium in chromizing low carbon steel.
A further purpose is to use between 25 and 85 percent by weight of finely divided inert'bodying'material based on the chromium content of the source of chromium in the chromizing compound.
A further purpose is to mix one volume of the fresh chromizing compound with from 2.5 to 3.5 volumes of expended compound for chromizing.
Further purposes appear in the specification and in the claims.
In the prior art, extensive use has been made of chromium diffusion into low carbon steel. As explained, for example, in Samuel U. S. Patent 2,536,774, chromizing may be carried out using a source of chromium and a bodying agent such as raw kaolin, along with an ammonium halide as a catalyst. The results obtained, however, are marred by the fact that the surface is considerably etched under the treatment, frequently producing discoloration, and the resultant finish is in general considerably rougher than the finish of the steel before treatment. and the advantages of chromizing from the standpoint of corrosion resistance and resistance to corrosion at elevated temperature have justified the use of chromizing.
There are, however, many applications in which the refinement of surface finish on the chromized surface is important and chromizing cannot be used unless it produces reliable surfaces of fine finish. To cite a few examples, there are surfaces which for hydraulic reasons should have a fine finish in connection with the flow of liquids or access at gases at high temperatures. There are also many machinery surfaces in which refinement of finish is important.
I have discovered that chromizing can be carried on consistently without the damage to the surface due to etching and discoloration and roughness of finish, while at the same time slightly improving the speed of diffusion. This renders the process applicable to parts which otherwise would not be consistently satisfactory in service as chromized by prior practices.
In accordance with the invention, the process is carried out using a chromizing compound which is in contact with or mmediately adjacent to the low carbon steel For some service this result is not objectionable,
2,825,658 Patented M'ar. 4, 19 58 ice being chromized at a temperature of 1650 to 1950 .F., and preferably at 1750" F. and in normal course for a time of at least three hours, usuallyinexcess of five hours, and most desirably abouteighteen hours.
The chromizing compound itself consists of a source of chromium in finely divided form, a catalyst and desirably an inert finely divided bodying agent.
I find that exceptionally good results are obtained with ammonium bromide as a catalyst, with less damage to the work, if the catalyst concentration is kept exceedingly low, basing the quantity of catalyst on the amount of chromium present in the source of chromium, which maybe chromium metal, or ferrochrome (preferably at least 65 percent chromium by weight). I find that the quantity of ammonium bromide should be between 0.06 and 0.26 percent by weight and preferably 0.01 percent by weight.
In addition an inert finely divided bodying agent is desirably used. This may be for example calcined clay, calcined kaolin or calcined alumina. The quantity of the inert bodying agent should be '25 to percent of the weight of the chromium present.
The source of chromium and the inert bodying agent as well as the catalyst should be finely divided, preferably through mesh per linear inch.
In a typical case the chromizing composition according to the invention may be as follows:
One suitable procedure for chromizing is to insert the low carbon steel parts to be chromized in a closed box, packing the chromizing compound around the parts. The box is provided with a vent which allows the bromine, hydrogen, ammonia and nitrogen formed by the dissociation of the ammonium bromide to sweep out the air. The vent is suitably closed by a molten slag seal.
The iron which is present as an impurity in the ferrochrome can be ignored in the composition since in any case iron is diffused from the steel to replace the chromium which diffuses into the steel.
Comparative tests were conducted making up identical chromizing compounds as follows:
Four boxes containing compounds A, B, C, and D packed around A151 1010 steel parts of identical size were placed side by side in the same furnace at 1750 F. and the chromizing treatment carried on for eighteen hours.
The results were asifollows'z Penetration of Chromium into Compound steel in inches A-Ammonlum iodide"...
B-Ammonium Chloride C-Ammonium Bromide- D-Ammonium Bifluoride- The finish'obtained on the parts subjected to the different treatments was as follows:
The parts chromized using the ammonium iodide catalyst had a good finish but it was marred by slight sinter ing of the chromizing compound on the parts. The parts chromized using ammonium chloride had a good finish, but inferior to those chromized using the iodide. ously than'in the case of the iodide.
The parts produced with ammonium, bromide had a very good finish, better than that from the iodide. This 'is the best finish which has been secured thus far in applicants experience.
The finish obtained with the bromide was the best se-' cured from the standpoint of evenness, complete absence of sintering and freedom from etching of the parts treat ed. 7 n In making up the tice, the normal technique is to retain the compound in the box from the'last treatment, and add to it one part by volume of new compound to 2.5 to 3.5 parts, preferably about 3 parts by volume of expended compound from previous treatments. This approximately Thepowder sintered on the surface more seriactual chromizing'mixture in piac-i compensates for the loss of compound and builds up a .proper chromizing potential in the new compound.
It will be evident that the invention is particularly advantageous where special refinements of surface are new and desire to secure by Letters Patent'is:
l. The method of chromizing, which comprises treating steel having a carbon content of 035 percent or less with exclusion of air at a temperature of from 1650 to 1950" F. for a time of at least three hours with a source of finely divided chromium and from.0.06 to.0.26 percent on the weight of the chromium of ammonium bromide. r
2. The method of claim- 1, in which the contentof ammonium bromide is 0.1 percent of the 'quantity of chromium.
3. The method of claim 1, in which the sourceof chromium is in the presence of from 25 to 85 percent on the weight of the chromium of inert'finely divided bodying material.
4. The method of claim 1, in 'which'about one part by volume of fresh chromizing compound accordingto claim 1 is used with between 2.5 and 3.5 parts by volume of chromizing compound according to claim 1 pro viously expended.
References Cited in the file of this patent UNITED STATES PATENTS 1,373,038 Weber Mar. 29, 1921 1,853,369 Marshall Apr. 12, 1932 2,046,638 Lauenstein et al. July 7, 1936 2,536,774
Samuel Jan. 2, 1951
Claims (1)
1. THE METHOD OF CHROMIZING, WHICH COMPRISES TREATING STEEL HAVING A CARBON CONTENT OF 0.35 PERCENT OR LESS WITH EXCLUSION OF AIR AT A TEMPERATURE OF FROM 1650 TO 1950*F. FOR A TIME OF AT LEAST THREE HOURS WITH A SOURCE OF FINELY DIVIDED CHROMIUM AND FROM 0.06 TO 0.26 PER CENT OF THE WEIGHT OF THE CHROMIUM OF AMMONIUM BROMIDE.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US460242A US2825658A (en) | 1954-10-04 | 1954-10-04 | Method of chromizing |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US460242A US2825658A (en) | 1954-10-04 | 1954-10-04 | Method of chromizing |
Publications (1)
Publication Number | Publication Date |
---|---|
US2825658A true US2825658A (en) | 1958-03-04 |
Family
ID=23827905
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US460242A Expired - Lifetime US2825658A (en) | 1954-10-04 | 1954-10-04 | Method of chromizing |
Country Status (1)
Country | Link |
---|---|
US (1) | US2825658A (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2921877A (en) * | 1958-03-13 | 1960-01-19 | David Craven | Process of chromizing air hardening tool steel |
US3015579A (en) * | 1959-06-15 | 1962-01-02 | Chromizing Corp | Metal coating process |
US3065108A (en) * | 1960-01-07 | 1962-11-20 | Chromalloy Corp | Method of applying a chromium coating to high temperature resistant materials |
DE2911018A1 (en) * | 1978-03-22 | 1979-09-27 | Electric Power Res Inst | ELECTRICALLY CONDUCTIVE, CORROSION-RESISTANT COMPONENT |
DE3334669A1 (en) * | 1983-09-24 | 1985-04-11 | Brown, Boveri & Cie Ag, 6800 Mannheim | Method of producing an electrochemical storage cell, and a storage cell produced thereby |
US6602550B1 (en) | 2001-09-26 | 2003-08-05 | Arapahoe Holdings, Llc | Method for localized surface treatment of metal component by diffusion alloying |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1373038A (en) * | 1919-03-31 | 1921-03-29 | Henry C P Weber | Process of producing metal substances |
US1853369A (en) * | 1927-12-27 | 1932-04-12 | Technimet Company | Formation of chromium alloy coatings |
US2046638A (en) * | 1932-04-22 | 1936-07-07 | Link Belt Co | Process of treating metal |
US2536774A (en) * | 1946-03-07 | 1951-01-02 | Diffusion Alloys Corp | Process of coating ferrous metal and heat pack mixture therefor |
-
1954
- 1954-10-04 US US460242A patent/US2825658A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1373038A (en) * | 1919-03-31 | 1921-03-29 | Henry C P Weber | Process of producing metal substances |
US1853369A (en) * | 1927-12-27 | 1932-04-12 | Technimet Company | Formation of chromium alloy coatings |
US2046638A (en) * | 1932-04-22 | 1936-07-07 | Link Belt Co | Process of treating metal |
US2536774A (en) * | 1946-03-07 | 1951-01-02 | Diffusion Alloys Corp | Process of coating ferrous metal and heat pack mixture therefor |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2921877A (en) * | 1958-03-13 | 1960-01-19 | David Craven | Process of chromizing air hardening tool steel |
US3015579A (en) * | 1959-06-15 | 1962-01-02 | Chromizing Corp | Metal coating process |
US3065108A (en) * | 1960-01-07 | 1962-11-20 | Chromalloy Corp | Method of applying a chromium coating to high temperature resistant materials |
DE2911018A1 (en) * | 1978-03-22 | 1979-09-27 | Electric Power Res Inst | ELECTRICALLY CONDUCTIVE, CORROSION-RESISTANT COMPONENT |
DE3334669A1 (en) * | 1983-09-24 | 1985-04-11 | Brown, Boveri & Cie Ag, 6800 Mannheim | Method of producing an electrochemical storage cell, and a storage cell produced thereby |
US6602550B1 (en) | 2001-09-26 | 2003-08-05 | Arapahoe Holdings, Llc | Method for localized surface treatment of metal component by diffusion alloying |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2536774A (en) | Process of coating ferrous metal and heat pack mixture therefor | |
US2825658A (en) | Method of chromizing | |
US3837901A (en) | Diffusion-coating of nickel-base superalloy articles | |
US2801187A (en) | Methods for obtaining superficial diffusion alloys, in particular chromium alloys | |
US2269601A (en) | Process for the manufacture of articles resistant to gaseous corrosion | |
US3222212A (en) | Process for chromizing | |
US2811466A (en) | Process of chromizing | |
US3061463A (en) | Metallic diffusion | |
US2851375A (en) | Ductile chromizing | |
US2855332A (en) | Method of chromizing ferrous metal | |
US2921877A (en) | Process of chromizing air hardening tool steel | |
US2881094A (en) | Process of coating with nickel by the decomposition of nickel carbonyl | |
US3157532A (en) | Methods of treating metallic powders | |
US1958575A (en) | Process for hardening iron, steel, and cast iron alloys by nitriding | |
US3015579A (en) | Metal coating process | |
GB785236A (en) | Method of and apparatus for producing coatings of hard carbides | |
US2885301A (en) | Chromizing coating | |
US2240146A (en) | Carburizing ferrous metals | |
US2868672A (en) | Oxidation resistant carbon and graphite bodies | |
US2157902A (en) | Impregnation of metals with silicon | |
US1923814A (en) | Nitriding | |
US2899332A (en) | Chromizing method and composition | |
CN114836711A (en) | Metal surface hardening method | |
US2017428A (en) | Protection of metal surfaces | |
US2095188A (en) | Iron and steel cementing bath composition |