US3778299A - Rotary barrel diffusion coating in molten lead - Google Patents
Rotary barrel diffusion coating in molten lead Download PDFInfo
- Publication number
- US3778299A US3778299A US00198404A US19840471A US3778299A US 3778299 A US3778299 A US 3778299A US 00198404 A US00198404 A US 00198404A US 19840471 A US19840471 A US 19840471A US 3778299 A US3778299 A US 3778299A
- Authority
- US
- United States
- Prior art keywords
- bath
- barrel
- lead
- diffusion coating
- molten lead
- 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
- 238000009792 diffusion process Methods 0.000 title abstract description 12
- 238000000576 coating method Methods 0.000 title abstract description 10
- 239000011248 coating agent Substances 0.000 title abstract description 9
- 238000000034 method Methods 0.000 abstract description 14
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 abstract description 13
- 238000005254 chromizing Methods 0.000 abstract description 8
- 238000007789 sealing Methods 0.000 abstract description 4
- 239000000470 constituent Substances 0.000 abstract description 2
- 239000011651 chromium Substances 0.000 description 12
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 11
- 229910052804 chromium Inorganic materials 0.000 description 11
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 238000011282 treatment Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910017060 Fe Cr Inorganic materials 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 229910002544 Fe-Cr Inorganic materials 0.000 description 1
- 229910000604 Ferrochrome Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000001464 adherent effect Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- UPHIPHFJVNKLMR-UHFFFAOYSA-N chromium iron Chemical compound [Cr].[Fe] UPHIPHFJVNKLMR-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000006163 transport media Substances 0.000 description 1
- 238000003466 welding Methods 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
- C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
- C23C10/18—Solid state diffusion of only metal elements or silicon into metallic material surfaces using liquids, e.g. salt baths, liquid suspensions
- C23C10/20—Solid state diffusion of only metal elements or silicon into metallic material surfaces using liquids, e.g. salt baths, liquid suspensions only one element being diffused
- C23C10/22—Metal melt containing the element to be diffused
Definitions
- ferrous articles It is desirable that the elements that are being transferred to the ferrous article to be maintained at some effective degree of solution concentration in the lead. It is also desirable that the ferrous articles not remain in contact with each other for prolonged time periods since the lead solution containing the transfer elements can not effectively maintain saturation and cause transfer under such conditions. Furthermore, said ferrous articles .will tend to bond together if allowed to reside in contact for prolonged time periods in the bath. It should also be pointed out that ferrous articles will float in a lead". bath and in order for diffusion coating to occur such articles must be maintained below the surface of the bath at least during most of the diffusion coating cycle. We have also found that it is desirable to exclude air or other gases that will react with the lead, chromium, or other ingredients of the bath.
- Either vacuum or an inert gas such as argon, for example, are suitable covers for the bath.
- an inert gas such as argon
- the bath sealed with only a small residual space such that very little contamination or evaporation can occur. If this space is small enough even air can be left in the space since it will not contaminate the bath significantly.
- the barrel is then sealed by welding or it is preheated, while the inside is either evacuated or purged with an inert cover gas, to a temperature near the chromizing temperature (-1950 F.) and then sealed with an external flange.
- the flange is normally located sufficiently far from the vaned barrel (the reaction chamber) such that a gasket, Teflon, for example, can be used for sealing.
- the external flange is connected to an insulated plug having a diameter slightly less the ID. of the barrel. If the plug is of sufficient length such that the flange is below the melting point of lead it is possible to use solid lead, which will form when the barrel is placed in a horizontal position, as a sealant.
- the barrel can be made of iron, or an alloy of iron that contains the diffusing elements being transferred, provided those elements are not extensively soluble in lead.
- Fe-Cr stainless steels such as A.I.S.I. type 446 (Fe-25 Cr). Under these conditions the chromium in the alloy will not be dissolved significantly since the chromium source in the bath will have a higher chromium content.
- Nickel-base alloys cannot be used, without an intermediate liner, since nickel is readily dissolved by lead.
- vanes For 4 in. ID. barrels we normally use 4 vanes, l in. long which are attached radially and spaced 90 apart. Barrels of this type have been rotated at speeds ranging from k to 6 rpm. and have resulted in very uniform chromizing of all of the parts in the barrel. For larger diameter barrels more numerous and longer vanes could be used to accomplish effective bath stirring and relative motion of the parts.
- ferrochromium we have successfully used both ferrochromium and un-alloyed chromium.
- the process can be used to diffuse other elements along with chromium or to diffuse other elements, soluble in lead, in the absence of chromium. Examples of the latter include aluminum, titanium, silicon, cobalt, nickel, and others.
- Our barrels are normally operated in a horizontal position but they could be operated in other non-vertical positions, up to 60 degrees from the horizontal, with suitable vaning designs.
- a method of diffusion coating ferrous articles using a lead bath containing a source of the diffusing elements comprising the steps of (a) providing a molten lead bath containing the elementor elements to be diffused;
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Coating With Molten Metal (AREA)
Abstract
A NOVEL PROCESS FOR DIFFUSION COATING OF FERROUS ARTICLES IN A LEAD BATH BY SEALING ALL OF THE CONSTITUENTS IN A BARREL WHICH IS ROTATED IN A NON-VERTICAL POSITION AT THE CHROMIZING TEMPERATURE. SUCH PROCESSING RESULTS IN EXTREMELY DIFFUSED ZONES ON IRREGULARLY-SHAPED PARTS.
Description
United sates pat nt once 3,778,299 ROTARY BARREL DIFFUSION COATING MOLTEN LEAD 1 John J. Rausch, Antioch, and Ray J. Van Thyne, Oak Fawn, 111., assignors to Surfalloy Corporation, Chicago,
l]. 1 Drawing. Continuation-impart of application Ser. No. 768,187, Oct. 16, 1968, now Patent No. 3,620,816.
This application Nov. 12, 1971, Ser. No. 198,404
- Int. Cl. C23c 9/00 US. Cl. 117-109 3 Claims ABSTRACT on THE DISCLOSURE A novel process for diffusion coating of ferrous articles in a lead bath by sealing all of the constituents in a barrel which is rotated in a non-vertical position at the chromizing temperature. Such processing results in extremely diffused zones on irregularly-shaped parts.
CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of our copending application Ser. No. 768,187 entitled, Method of Diffusion Coating Metal Substrates Using Molten Lead as Transport Medium, filed Oct. 16, 1968 now US. Pat. 3,620,816.
BACKGROUND OF THE INVENTION In our copending US. patent application (Ser. No. 768,187) now U.S. Pat. 3,620,816 there is described a diffusion coating process in which a metal article is surface alloyed by contacting the article with molten lead containing one or more diffusing elements. This process particularly provides chromium impregnated (chromized) ferrous articles which have good resistance to corrosion. In general, the process involves immersing the article to be coated in a molten lead bath for a predetermined time, removing the diffusion coated article from the bath, and thereafter cleaning the article to remove adherent lead and bath residue. In order for the process to be carried out more effectively we have found that some degree of agitation of the parts and the bath must occur. It is desirable that the elements that are being transferred to the ferrous article to be maintained at some effective degree of solution concentration in the lead. It is also desirable that the ferrous articles not remain in contact with each other for prolonged time periods since the lead solution containing the transfer elements can not effectively maintain saturation and cause transfer under such conditions. Furthermore, said ferrous articles .will tend to bond together if allowed to reside in contact for prolonged time periods in the bath. It should also be pointed out that ferrous articles will float in a lead". bath and in order for diffusion coating to occur such articles must be maintained below the surface of the bath at least during most of the diffusion coating cycle. We have also found that it is desirable to exclude air or other gases that will react with the lead, chromium, or other ingredients of the bath. Either vacuum or an inert gas such as argon, for example, are suitable covers for the bath. However, if the contained space above the bath is large the impurities present in the atmosphere can cause significant contamination of the bath. Furthermore, if that space is large a significant amount of lead is lost by evaporation. Thus it is most desirable to have the bath sealed with only a small residual space such that very little contamination or evaporation can occur. If this space is small enough even air can be left in the space since it will not contaminate the bath significantly.
We have discovered an effective means of diffusion coating with our lead bath process that eliminates all of the problems heretofore described. In this method, all of 3,778,299 Patented Dec. 11, 1 973 DESCRIPTION OF THE INVENTION When the process is used for chromizing, the ferrous parts, chromium source and other diffusing elements are charged into the barrel which is heated to a temperature in the range 600 to 800 F. The barrel is continuously purged with argon prior to and during the filling cycle to avoid oxidation of the materials. Molten lead is poured into the barrel until about of the volume is filled With lead and the other materials. The barrel is then sealed by welding or it is preheated, while the inside is either evacuated or purged with an inert cover gas, to a temperature near the chromizing temperature (-1950 F.) and then sealed with an external flange. The flange is normally located sufficiently far from the vaned barrel (the reaction chamber) such that a gasket, Teflon, for example, can be used for sealing. The external flange is connected to an insulated plug having a diameter slightly less the ID. of the barrel. If the plug is of sufficient length such that the flange is below the melting point of lead it is possible to use solid lead, which will form when the barrel is placed in a horizontal position, as a sealant.
The barrel can be made of iron, or an alloy of iron that contains the diffusing elements being transferred, provided those elements are not extensively soluble in lead. For chromizing, we frequently use Fe-Cr stainless steels such as A.I.S.I. type 446 (Fe-25 Cr). Under these conditions the chromium in the alloy will not be dissolved significantly since the chromium source in the bath will have a higher chromium content. Nickel-base alloys cannot be used, without an intermediate liner, since nickel is readily dissolved by lead.
For 4 in. ID. barrels we normally use 4 vanes, l in. long which are attached radially and spaced 90 apart. Barrels of this type have been rotated at speeds ranging from k to 6 rpm. and have resulted in very uniform chromizing of all of the parts in the barrel. For larger diameter barrels more numerous and longer vanes could be used to accomplish effective bath stirring and relative motion of the parts.
The reliability of our rotating barrel process has been demonstrated by many examples. Over 35 separate runs have been made using ferrous parts with internal holes and threads. Typically the chromizing treatments were 1950 F. for 4 hours, which produces a chromized layer about 0.003 inch deep on very low carbon-containing parts. Of course other treatments may be used depending upon the desired chromizing zone depth. Over parts that were selected at random have been sectioned and metallographic examination at 100x magnification showed that in every example the chromized layer was uniform.
We have successfully used both ferrochromium and un-alloyed chromium. In addition to chromium per se, the process can be used to diffuse other elements along with chromium or to diffuse other elements, soluble in lead, in the absence of chromium. Examples of the latter include aluminum, titanium, silicon, cobalt, nickel, and others. Our barrels are normally operated in a horizontal position but they could be operated in other non-vertical positions, up to 60 degrees from the horizontal, with suitable vaning designs.
We claim as our invention:
1. A method of diffusion coating ferrous articles using a lead bath containing a source of the diffusing elements comprising the steps of (a) providing a molten lead bath containing the elementor elements to be diffused;
(b) placing said bath and said ferrous articles in a sealable, vaned cylindrical barrel; and filling said barrel therewith to minimize free space over said bath;
(c) sealing said barrel;
(d) rotating said barrel in a position ranging from horizontal to 60 degrees from the horizontal While maintaining the bath therein at a molten temperature and while rotating maintaining said ferrous articles substantially submerged within said bath; and
(e) maintaining said rotation for an adequate time to diffusion treat said ferrous articles.
2. A method as defined in claim 1 in which the difiusing element is chromium.
3. A method as defined in claim 1 wherein the barrel is held in and rotated in a horizontal position.
References Cited UNITED STATES PATENTS 3,377,195 4/1968 Sneesby 117114 R 2,793,965 5/1957 Myers et al. 117109 2,864,731 12/1958 Gurinsky et al. 1486.l1 2,929,741 3/1960 Steinberg 117-118 X 135,339 1/1873 Hunt 117-109 X 1,713,233 5/ 1929 Kelley 1171 14 BX 2,910,379 10/1959 Gurinsky 117118 X 2,926,111 2/ 1960 Schweitzer et al. 1486.11
15 RALPH s. KENDALL, Primary Examiner US. 01. X.R. 117-414 R, 119
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US00198404A US3778299A (en) | 1968-10-16 | 1971-11-12 | Rotary barrel diffusion coating in molten lead |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US76818768A | 1968-10-16 | 1968-10-16 | |
| US00198404A US3778299A (en) | 1968-10-16 | 1971-11-12 | Rotary barrel diffusion coating in molten lead |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3778299A true US3778299A (en) | 1973-12-11 |
Family
ID=26893748
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US00198404A Expired - Lifetime US3778299A (en) | 1968-10-16 | 1971-11-12 | Rotary barrel diffusion coating in molten lead |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US3778299A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4372995A (en) * | 1981-06-08 | 1983-02-08 | John J. Rausch | Process of making surface alloyed parts |
| US4394422A (en) * | 1981-06-08 | 1983-07-19 | Ray J. Van Thyne | Bonded structure and process of making same |
| WO2002070774A1 (en) * | 2001-03-05 | 2002-09-12 | GWP Gesellschaft für Werkstoffprüfung mbH | Method for hardening metal workpieces |
-
1971
- 1971-11-12 US US00198404A patent/US3778299A/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4372995A (en) * | 1981-06-08 | 1983-02-08 | John J. Rausch | Process of making surface alloyed parts |
| US4394422A (en) * | 1981-06-08 | 1983-07-19 | Ray J. Van Thyne | Bonded structure and process of making same |
| WO2002070774A1 (en) * | 2001-03-05 | 2002-09-12 | GWP Gesellschaft für Werkstoffprüfung mbH | Method for hardening metal workpieces |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: MATERIAL SCIENCES CORPORATION ELK GROVE VILLAGE, I Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:RAUSCH, JOHN J.;VAN THYNE, RAY J.;REEL/FRAME:004220/0353 Effective date: 19831025 |
|
| AS | Assignment |
Owner name: RAUSCH, JOHN J. ANTIOCH ILLINOIS Free format text: ASSIGNMENT OF A PART OF ASSIGNORS INTEREST;ASSIGNOR:MATERIAL SCIENCES CORPORATION;REEL/FRAME:004388/0156 Effective date: 19850403 Owner name: VAN, RAY J. INVERNESS ILLINOIS Free format text: ASSIGNMENT OF A PART OF ASSIGNORS INTEREST;ASSIGNOR:MATERIAL SCIENCES CORPORATION;REEL/FRAME:004388/0156 Effective date: 19850403 |