CA1159627A - Process for producing metallic chilled cast mold parts and their use - Google Patents
Process for producing metallic chilled cast mold parts and their useInfo
- Publication number
- CA1159627A CA1159627A CA000366507A CA366507A CA1159627A CA 1159627 A CA1159627 A CA 1159627A CA 000366507 A CA000366507 A CA 000366507A CA 366507 A CA366507 A CA 366507A CA 1159627 A CA1159627 A CA 1159627A
- Authority
- CA
- Canada
- Prior art keywords
- bodies
- mold
- hard
- process according
- foaming
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D19/00—Casting in, on, or around objects which form part of the product
- B22D19/06—Casting in, on, or around objects which form part of the product for manufacturing or repairing tools
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Mold Materials And Core Materials (AREA)
- Manufacture Of Alloys Or Alloy Compounds (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The invention provides a process for the production of hard metallic cast molded parts with areas of increased wear resistance created by the incorporation of mold bodies in the casting mold which produces a local alloying effect with a smelt material, characterized in that a basic metal smelt of hard manganese steel and porous mold bodies are used, these bodies being formed by the foaming of fine particle ferroboron with an aqueous solution of alkali silicate.
The invention provides a process for the production of hard metallic cast molded parts with areas of increased wear resistance created by the incorporation of mold bodies in the casting mold which produces a local alloying effect with a smelt material, characterized in that a basic metal smelt of hard manganese steel and porous mold bodies are used, these bodies being formed by the foaming of fine particle ferroboron with an aqueous solution of alkali silicate.
Description
~ 15~27 The present in~ention relates to a process for the production of hard metallic cast molded parts with areas of increased wear resistance that are created by including in the mold mold bodies tha* cause a local alloying effect with the castinc~ materials in the casting mold. The present invention also relates to the use c)f hard cast molded parts of this type as bueket teeth and/or bucket lips for exeavators.
When ores, rocks or other natural or artifieial material are moved or reduced, a large number of technical problems are ereated with regard to the material that is used for the wearing parts of the tools used in these proeesses.
Partieular problems occur when the material that is to be reduced, in addition to being very hard, is also very tough.
With regard to materials of this kind, for the reduction of which tools used up to now made of hard manganese steel lasts only a short while, the additional reduetion used for further proeessing is then only economically feasible if the value of the produet is far greater than the resultlng wear costs ineurred for any given quantity. The difficulties that are eaused for the redueing machinery or those of its parts that are subjeet to wear result, in particular, because of the ~aet that in addit~on to the frictional loads that occur the material that is to be broken down also eauses impaet and eoneussion loads on the wearing parts.
In order to improve the resistanee of heavily loaded cast parts, it has been proposed that a surface hardening effeet on those areas that are subjected to large wearing loads ean be improved by the application of alloying pastes on certain areas of the mold prior to east~ncJ. This measure, used during easting, has considerable disadvantages, namely, it is ineonvenient to use, and uneertain or impreeise with regard to the extent o~ teehnological improvement, and is slight with /
, .
1 15~27 regard to the depth of the alloy~ ef~ect since only thin la~ers of paste can be used.
Another measure which is usea with the same purpose, consists in embeddiny hard portlons in the hollow volume of the càsting mold, these being surrounded in the filled mold portion by the matrix of the molding material and then bringing about a reduction in wear. Even thou~h the effective de~th is I -considerably greater than that achieved by the use of alloying pastes, this measure still cannot be regarded as completely satisfactory since additional steps must be taken, such as the use of wire netting or suctlon, in order to fix the individual hardening material grains or pieces in-the hollow portion of the mold form in order that even distribution is ensured throughout -.
the cast part.
Thus, the present invention reduces or desirably eliminates these disadvantages and provides a process which makes it possible to produce wear resistant cast parts with the necessary combination of hardness and toughness such as to meet the partlcular demands and thus to produce them in the best possible manner in the most cost effective way.
According to the present invention there is provided a process for the production of hard metallic cast molded parts with.areas of increased wear resistance created by the incorpor-ation of mold bodies in the casting mold whlch produces a local alloying effect with a smelt material, characterized in that a basic metal smelt of hard manganese steel and porous mold bodies are used, these bodies being formed by the foaming of fine particle.ferroboron with an aqueous solution of an alkali silicate.
Thus, according to the process of the present invention, a basic metal smelt consistin~ of hard manganese steel and a porous mold body is used, this being pr~duced by foaming a fine grain ferroboron with an aqueous alkall-silicate soluti~n, I ~5~2~
desirably with additional hardening materials mixed in, preferably in core boxes.
The fact that powdered ferroboron reacts with an aqueous alkali-silicate solution during foaming thus forming a porous ~old body is most surpris~ng and has no counterpart in the behaviour of other iron alloys, e.g., iron manganese, under similar conditions. The reaction ts accelerated by heating, so that it appears appropri~te for the production of a mold body that the foaming takes place at a temperature of at least approximately 80C. Even though it is preferred that the form reyuired for the porous mold body is achieved by the use of suitàble mold boxes during the hardening of the foamed ~ass, the shaping can also be carried out after the foam has hardened.
It is, of course, understood that the resulting pore volume is effected primarily by the degree to which the mold is filled as well as by the concentration of the silicate solution. Even though the reaction mechanism for the foaming has not been completely explained, it can be stated that this does not involve a pyrolitic decomposition.
. , .
The present invention will be further illustrated by way of the following Examples.
Exam~
A fine grain ferroboron (grain size 0.02 - 0.075 mm) was mixed with a 30~ solution of sodium silicate to form a viscous paste. This paste was then used as a filling for approximately one half of the volume of the core boxes which were used to shape the bucket teeth. The core boxes were then heated to 120C for a peri~d of two hours,thus forming the porous mold bodies, in which the pore size was, on average, 0.7 mm with the pore volume amounting to approximately 50%. These four mold bodies were then usea in a so-called "green" casting mold made of silicate sand for the production of the bucket teeth and secured by means ; -3-' " l 159~27 of mold nails in such a manner th~t approximately 50% was exposed relative to the surface area of the tooth sides. Casting was carried out with a smelt of hard manganese steel at a pouring temperature of 153C. When used, the bucket teeth produced in this manner exhibited outstanding stength.
Exam~le 2., Mold bodies having a pore volume of approximately 50%, and measuring 100 x 100 x 15 mm, were produced in a core box as in Example 1 from a paste-like mixture of an intimate mix consisting of 80% by weight of the ferroboron described in Example 1, and 20~ by weight ca~borundum (grain size 0.05 - 0.1 mm) with a 30% solution of sodium silicate. These mold bodies were incorporated in the edge areas of the lips of buckets at equal distances of approximately 20 mm in the casting mold and secured thereto with moldnails. Castlng was carried out with a smelt of hard manyanese steel at a temperature of 1540C. The excavator buckets that were used-in tin mines and thus exposed to particularly high rates of wear could be improved several fold in this manner.
The present invention will be further illustrated by way of the accompanying drawings in which:
Figs. 1 through 4 are photo micrographs of edge zone structures (Figs. l to 3) and basic metal matrix (Fig. 4) at 250 x magnification of cast metal parts in accordance with the present invention.
In order to dem~nstrate the hardness characteristics of the cast parts produced according to the invention, determined primarily by the pore volume of the porous ferroboron mold bodies, the edge alloy zones were examined by means of etching using a 2~ solution of HNO3 and these were related to the edge zone structures ~Figs. l - 3) of the structure of the basic metal matriX of hard mang~nese steel (Fig. 4) shown at a 250 x ~ 4 ,' ' l 1~9~
magnification.
Figure 1 shows such a structure obtained by using a ferroboron mold body having a pore volume of 20% with borideute-ktikum, in which connection 90% of the ground surface displays a hardness of 820 - 860 HV. I.n the structure shown in Figure 2 the pore volume of the mold body amounted to 40%; the surface proportion had 800 ~ 860 HV has been reduced by approximately 50~ whereas the basic mass (Mn-austenite containing boron) was at 300 HV.. Figure 3 shows a structure in which the pore ~olume amounted to 60~. ~he proportion of the surface at 800 -860 HV amounted to 30% and the hardness of the basic mass was also 300 HV. Finally, Fig~ 4 shows the structure of the basic metal matrix, that is to say hard manganese steel, at the same magnification; its hardness amounted to 240 HV.`
~ -5-! ~, ~ ' . ~ ` .
When ores, rocks or other natural or artifieial material are moved or reduced, a large number of technical problems are ereated with regard to the material that is used for the wearing parts of the tools used in these proeesses.
Partieular problems occur when the material that is to be reduced, in addition to being very hard, is also very tough.
With regard to materials of this kind, for the reduction of which tools used up to now made of hard manganese steel lasts only a short while, the additional reduetion used for further proeessing is then only economically feasible if the value of the produet is far greater than the resultlng wear costs ineurred for any given quantity. The difficulties that are eaused for the redueing machinery or those of its parts that are subjeet to wear result, in particular, because of the ~aet that in addit~on to the frictional loads that occur the material that is to be broken down also eauses impaet and eoneussion loads on the wearing parts.
In order to improve the resistanee of heavily loaded cast parts, it has been proposed that a surface hardening effeet on those areas that are subjected to large wearing loads ean be improved by the application of alloying pastes on certain areas of the mold prior to east~ncJ. This measure, used during easting, has considerable disadvantages, namely, it is ineonvenient to use, and uneertain or impreeise with regard to the extent o~ teehnological improvement, and is slight with /
, .
1 15~27 regard to the depth of the alloy~ ef~ect since only thin la~ers of paste can be used.
Another measure which is usea with the same purpose, consists in embeddiny hard portlons in the hollow volume of the càsting mold, these being surrounded in the filled mold portion by the matrix of the molding material and then bringing about a reduction in wear. Even thou~h the effective de~th is I -considerably greater than that achieved by the use of alloying pastes, this measure still cannot be regarded as completely satisfactory since additional steps must be taken, such as the use of wire netting or suctlon, in order to fix the individual hardening material grains or pieces in-the hollow portion of the mold form in order that even distribution is ensured throughout -.
the cast part.
Thus, the present invention reduces or desirably eliminates these disadvantages and provides a process which makes it possible to produce wear resistant cast parts with the necessary combination of hardness and toughness such as to meet the partlcular demands and thus to produce them in the best possible manner in the most cost effective way.
According to the present invention there is provided a process for the production of hard metallic cast molded parts with.areas of increased wear resistance created by the incorpor-ation of mold bodies in the casting mold whlch produces a local alloying effect with a smelt material, characterized in that a basic metal smelt of hard manganese steel and porous mold bodies are used, these bodies being formed by the foaming of fine particle.ferroboron with an aqueous solution of an alkali silicate.
Thus, according to the process of the present invention, a basic metal smelt consistin~ of hard manganese steel and a porous mold body is used, this being pr~duced by foaming a fine grain ferroboron with an aqueous alkall-silicate soluti~n, I ~5~2~
desirably with additional hardening materials mixed in, preferably in core boxes.
The fact that powdered ferroboron reacts with an aqueous alkali-silicate solution during foaming thus forming a porous ~old body is most surpris~ng and has no counterpart in the behaviour of other iron alloys, e.g., iron manganese, under similar conditions. The reaction ts accelerated by heating, so that it appears appropri~te for the production of a mold body that the foaming takes place at a temperature of at least approximately 80C. Even though it is preferred that the form reyuired for the porous mold body is achieved by the use of suitàble mold boxes during the hardening of the foamed ~ass, the shaping can also be carried out after the foam has hardened.
It is, of course, understood that the resulting pore volume is effected primarily by the degree to which the mold is filled as well as by the concentration of the silicate solution. Even though the reaction mechanism for the foaming has not been completely explained, it can be stated that this does not involve a pyrolitic decomposition.
. , .
The present invention will be further illustrated by way of the following Examples.
Exam~
A fine grain ferroboron (grain size 0.02 - 0.075 mm) was mixed with a 30~ solution of sodium silicate to form a viscous paste. This paste was then used as a filling for approximately one half of the volume of the core boxes which were used to shape the bucket teeth. The core boxes were then heated to 120C for a peri~d of two hours,thus forming the porous mold bodies, in which the pore size was, on average, 0.7 mm with the pore volume amounting to approximately 50%. These four mold bodies were then usea in a so-called "green" casting mold made of silicate sand for the production of the bucket teeth and secured by means ; -3-' " l 159~27 of mold nails in such a manner th~t approximately 50% was exposed relative to the surface area of the tooth sides. Casting was carried out with a smelt of hard manganese steel at a pouring temperature of 153C. When used, the bucket teeth produced in this manner exhibited outstanding stength.
Exam~le 2., Mold bodies having a pore volume of approximately 50%, and measuring 100 x 100 x 15 mm, were produced in a core box as in Example 1 from a paste-like mixture of an intimate mix consisting of 80% by weight of the ferroboron described in Example 1, and 20~ by weight ca~borundum (grain size 0.05 - 0.1 mm) with a 30% solution of sodium silicate. These mold bodies were incorporated in the edge areas of the lips of buckets at equal distances of approximately 20 mm in the casting mold and secured thereto with moldnails. Castlng was carried out with a smelt of hard manyanese steel at a temperature of 1540C. The excavator buckets that were used-in tin mines and thus exposed to particularly high rates of wear could be improved several fold in this manner.
The present invention will be further illustrated by way of the accompanying drawings in which:
Figs. 1 through 4 are photo micrographs of edge zone structures (Figs. l to 3) and basic metal matrix (Fig. 4) at 250 x magnification of cast metal parts in accordance with the present invention.
In order to dem~nstrate the hardness characteristics of the cast parts produced according to the invention, determined primarily by the pore volume of the porous ferroboron mold bodies, the edge alloy zones were examined by means of etching using a 2~ solution of HNO3 and these were related to the edge zone structures ~Figs. l - 3) of the structure of the basic metal matriX of hard mang~nese steel (Fig. 4) shown at a 250 x ~ 4 ,' ' l 1~9~
magnification.
Figure 1 shows such a structure obtained by using a ferroboron mold body having a pore volume of 20% with borideute-ktikum, in which connection 90% of the ground surface displays a hardness of 820 - 860 HV. I.n the structure shown in Figure 2 the pore volume of the mold body amounted to 40%; the surface proportion had 800 ~ 860 HV has been reduced by approximately 50~ whereas the basic mass (Mn-austenite containing boron) was at 300 HV.. Figure 3 shows a structure in which the pore ~olume amounted to 60~. ~he proportion of the surface at 800 -860 HV amounted to 30% and the hardness of the basic mass was also 300 HV. Finally, Fig~ 4 shows the structure of the basic metal matrix, that is to say hard manganese steel, at the same magnification; its hardness amounted to 240 HV.`
~ -5-! ~, ~ ' . ~ ` .
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the production of hard metallic cast molded parts with areas of increased wear resistance created by the incorporation of mold bodies in the casting mold which produces a local alloying effect with a smelt material, character-ized in that a basic metal smelt of hard manganese steel and porous mold bodies are used, these bodies being formed by the foaming of fine particle ferroboron with an aqueous solution of alkali silicate.
2. A process according to claim 1, in which an additional hardening material is present in the foaming.
3. A process according to claim 2, in which the material is carborundum.
4. A process according to claim 1, 2 or 3, in which the foamed bodies are formed in core boxes.
5. A process according to claim 1, in which the molded parts are selected from bucket teeth and bucket lips for excavators.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| ATA7858/79 | 1979-12-13 | ||
| AT785879A AT375035B (en) | 1979-12-13 | 1979-12-13 | METHOD FOR THE PRODUCTION OF METAL CHIMED MOLDED PARTS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1159627A true CA1159627A (en) | 1984-01-03 |
Family
ID=3600157
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000366507A Expired CA1159627A (en) | 1979-12-13 | 1980-12-10 | Process for producing metallic chilled cast mold parts and their use |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0030933B1 (en) |
| AT (1) | AT375035B (en) |
| CA (1) | CA1159627A (en) |
| DE (1) | DE3063917D1 (en) |
| GB (1) | GB2065523B (en) |
| WO (1) | WO1981001673A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1004573A4 (en) * | 1990-09-20 | 1992-12-15 | Magotteaux Int | Process for producing a piece bimetallic foundry and wear piece made thereby. |
| JP2852867B2 (en) * | 1994-05-13 | 1999-02-03 | 株式会社小松製作所 | Method for producing wear-resistant parts and wear-resistant parts |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE719151C (en) * | 1940-03-30 | 1942-03-30 | Wilhelm Rominger | Process for the production of highly stressed or specifically light cast bodies |
| US3189958A (en) * | 1961-05-12 | 1965-06-22 | Trainer Associates Inc | Method of bonding inserts into castings |
| DE1508887A1 (en) * | 1966-08-27 | 1970-03-05 | Kloth Senking Ag | Cast part provided with lumpy inclusion bodies |
| DE2016312B2 (en) * | 1970-04-06 | 1971-05-13 | Verschleiß Technik Dr Ing Hans Wahl, 7304 Ruit | Coating of soft iron cores with alloys |
| GB1478943A (en) * | 1975-01-09 | 1977-07-06 | Fiber Materials | Metal/graphite fibre composite |
| US4024902A (en) * | 1975-05-16 | 1977-05-24 | Baum Charles S | Method of forming metal tungsten carbide composites |
| DE2714906C3 (en) * | 1977-04-02 | 1981-11-05 | Verschleiß-Technik Dr.-Ing. Hans Wahl GmbH & Co, 7302 Ostfildern | Clamping for castings at risk of breakage |
-
1979
- 1979-12-13 AT AT785879A patent/AT375035B/en not_active IP Right Cessation
-
1980
- 1980-12-03 DE DE8080890143T patent/DE3063917D1/en not_active Expired
- 1980-12-03 EP EP19800890143 patent/EP0030933B1/en not_active Expired
- 1980-12-09 WO PCT/AT1980/000034 patent/WO1981001673A1/en unknown
- 1980-12-10 CA CA000366507A patent/CA1159627A/en not_active Expired
- 1980-12-15 GB GB8040126A patent/GB2065523B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0030933B1 (en) | 1983-06-22 |
| GB2065523A (en) | 1981-07-01 |
| DE3063917D1 (en) | 1983-07-28 |
| WO1981001673A1 (en) | 1981-06-25 |
| GB2065523B (en) | 1983-05-25 |
| EP0030933A1 (en) | 1981-06-24 |
| AT375035B (en) | 1984-06-25 |
| ATA785879A (en) | 1983-11-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |