CA1221560A - Work-hardenable austenitic manganese steel and method for the production thereof - Google Patents
Work-hardenable austenitic manganese steel and method for the production thereofInfo
- Publication number
- CA1221560A CA1221560A CA000439018A CA439018A CA1221560A CA 1221560 A CA1221560 A CA 1221560A CA 000439018 A CA000439018 A CA 000439018A CA 439018 A CA439018 A CA 439018A CA 1221560 A CA1221560 A CA 1221560A
- Authority
- CA
- Canada
- Prior art keywords
- percent
- weight
- range
- melt
- casting
- 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
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Heat Treatment Of Steel (AREA)
- Materials For Medical Uses (AREA)
Abstract
INVENTOR: BERND KOS
INVENTION: WORK-HARDENABLE AUSTENITIC MANGANESE STEEL AND
METHOD FOR THE PRODUCTION THEREOF
ABSTRACT OF THE DISCLOSURE
A work-hardenable austenitic manganese steel has a base composition (each in percent by weight) of 0.7 to 1.7 carbon, 5.0 to 18.0 manganese, 0 to 3.0 chromium, 0 to 4.0 nickel, 0 to 2.5 molybdenum, 0.1 to 0.9 silicon, up to 0.1 phosphorus and contains micro-alloying elements of 0.0 to 0.20 titanium, 0.0 to 0.05 zirconium and 0.0 to 0.05 vanadium; the remainder being iron and impurities arising from the melting process. The ratio of carbon to manganese is in the range of 1 : 4 to 1 : 14 and the total amount of micro-alloying elements is limited to a range of 0.002 to 0.25 percent by weight. The melt of the base composition is tapped at 1,450°C to 1,600°C into a casting ladle in which the micro-alloying elements are added. An ingot is cast, cooled, reheated to austenitization temperatures and quenched.
INVENTION: WORK-HARDENABLE AUSTENITIC MANGANESE STEEL AND
METHOD FOR THE PRODUCTION THEREOF
ABSTRACT OF THE DISCLOSURE
A work-hardenable austenitic manganese steel has a base composition (each in percent by weight) of 0.7 to 1.7 carbon, 5.0 to 18.0 manganese, 0 to 3.0 chromium, 0 to 4.0 nickel, 0 to 2.5 molybdenum, 0.1 to 0.9 silicon, up to 0.1 phosphorus and contains micro-alloying elements of 0.0 to 0.20 titanium, 0.0 to 0.05 zirconium and 0.0 to 0.05 vanadium; the remainder being iron and impurities arising from the melting process. The ratio of carbon to manganese is in the range of 1 : 4 to 1 : 14 and the total amount of micro-alloying elements is limited to a range of 0.002 to 0.25 percent by weight. The melt of the base composition is tapped at 1,450°C to 1,600°C into a casting ladle in which the micro-alloying elements are added. An ingot is cast, cooled, reheated to austenitization temperatures and quenched.
Description
122~
BP~CKGROUND OF THE INVENTION
_ _ _ _ _ The present invention relates to a work-hardenable austenitic manganese (Hadfield type) steel having an elongation at rupture of 10 percent to 80 percent, and to a method for the production thereof.
Work-hardenable austenitic manganese steels have a wide range of application in the form of castings, forgings and rolled material. This wide use is due, in particular, to its high inherent ductility and satisfactory work-hardening ability. Uses range from castings for crushing hard materials to shell-proof objects. The valuable properties of manganese steel reside in the combina~ion of the above-mentioned properties of work-hardening and ductility. Work~hardening takes place whenever manganese steel is subjected to mechanical stress, for example, by shock or impact which converts the austenite in the surface layer partly to an epsilon martensite. Measurements of work-hardening reveal an increase of between 200 and 550 in Brinell hardness.
Thus, castings, forgings and the like increase in hardness during use, if they are subjected to mechanical stress.
However, since such objects are also subjected to abrasion, the surface layer is constantly being removed, leaving austenite at the surface. This austenite is again ~f.
conver-ted by renewed mechanical stress. The alloy located below the surface layer is highly ductile, and manganese steels can therefore withstand high mechanical impact stress without any danger of rupture, even in the case of objects having thin walls.
ln the case of objects to be made of manganese steel, it is essential that a preliminary mold or ingot-casting be produced in order to predetermine the properties of objects made therefrom. If the casting has an unduly coarse structure, the object will have low ductility. In the cases of large castings, it is known that grain-size varies over the cross-section. At the outside is a thin, relatively fine-grained edge zone, followed by a zone consisting of coarse columnar crystals, followed, in turn, by the globulitic structure at the center of the casting. Although the steel is essentially austenitic and work-hardenable over its entire cross-section, great differences arise in its mechanical properties, especially in its ductility, as a result of these structural differences.
In order to achieve the most uniform ductility possible over the entire cross-section, it has already been proposed that the casting temperature be kept as low as possible, for example at 1410C, since increasing super-cooling should cause the number of nuclei to grow and produce a finer grain-size. These low casting temperatures, however, cause major production problems.
For instance, ~-shuts occur in the casting and the rheological pxoperties of the molten metal are such that the mold is no longer accurately filled, especially at the edges. Furthermore, the molten metal solidifies, during casting, on the lining of the ladle, leading to ladle skulls or skins which must be removed and reprocessed.
During actual casting, the plug may stick in the outlet, which means that pouring must be interrupted. It will easily be gathered from the foregoing that the economic disadvantages to be incurred for a non-reproducible refining of the grain are so serious that this low-temperature-casting process has not been able to gain acceptance.
Another method of refining the grain involves a specific heat-treatment, the casting being annealed for 8 to 12 hours at a temperature of between 500C and 600C, whereby a large proportion of the austenite is converted into pearlite. This is followed by austenitizing-annealing at a temperature of between 970C and 1110C. This double structural change is supposed to produce a finer grain, but it also causes the product to become extremely brittle during the heat-treatment, so that it ruptures without any
BP~CKGROUND OF THE INVENTION
_ _ _ _ _ The present invention relates to a work-hardenable austenitic manganese (Hadfield type) steel having an elongation at rupture of 10 percent to 80 percent, and to a method for the production thereof.
Work-hardenable austenitic manganese steels have a wide range of application in the form of castings, forgings and rolled material. This wide use is due, in particular, to its high inherent ductility and satisfactory work-hardening ability. Uses range from castings for crushing hard materials to shell-proof objects. The valuable properties of manganese steel reside in the combina~ion of the above-mentioned properties of work-hardening and ductility. Work~hardening takes place whenever manganese steel is subjected to mechanical stress, for example, by shock or impact which converts the austenite in the surface layer partly to an epsilon martensite. Measurements of work-hardening reveal an increase of between 200 and 550 in Brinell hardness.
Thus, castings, forgings and the like increase in hardness during use, if they are subjected to mechanical stress.
However, since such objects are also subjected to abrasion, the surface layer is constantly being removed, leaving austenite at the surface. This austenite is again ~f.
conver-ted by renewed mechanical stress. The alloy located below the surface layer is highly ductile, and manganese steels can therefore withstand high mechanical impact stress without any danger of rupture, even in the case of objects having thin walls.
ln the case of objects to be made of manganese steel, it is essential that a preliminary mold or ingot-casting be produced in order to predetermine the properties of objects made therefrom. If the casting has an unduly coarse structure, the object will have low ductility. In the cases of large castings, it is known that grain-size varies over the cross-section. At the outside is a thin, relatively fine-grained edge zone, followed by a zone consisting of coarse columnar crystals, followed, in turn, by the globulitic structure at the center of the casting. Although the steel is essentially austenitic and work-hardenable over its entire cross-section, great differences arise in its mechanical properties, especially in its ductility, as a result of these structural differences.
In order to achieve the most uniform ductility possible over the entire cross-section, it has already been proposed that the casting temperature be kept as low as possible, for example at 1410C, since increasing super-cooling should cause the number of nuclei to grow and produce a finer grain-size. These low casting temperatures, however, cause major production problems.
For instance, ~-shuts occur in the casting and the rheological pxoperties of the molten metal are such that the mold is no longer accurately filled, especially at the edges. Furthermore, the molten metal solidifies, during casting, on the lining of the ladle, leading to ladle skulls or skins which must be removed and reprocessed.
During actual casting, the plug may stick in the outlet, which means that pouring must be interrupted. It will easily be gathered from the foregoing that the economic disadvantages to be incurred for a non-reproducible refining of the grain are so serious that this low-temperature-casting process has not been able to gain acceptance.
Another method of refining the grain involves a specific heat-treatment, the casting being annealed for 8 to 12 hours at a temperature of between 500C and 600C, whereby a large proportion of the austenite is converted into pearlite. This is followed by austenitizing-annealing at a temperature of between 970C and 1110C. This double structural change is supposed to produce a finer grain, but it also causes the product to become extremely brittle during the heat-treatment, so that it ruptures without any
2~
deformation even under low mechanical stress. Another major disadvantage is that the process re~uires a considerable amount of energy.
Fox these reasons, attempts have already been made to achieve grain refining by adding further alloying elements, for example chromium, titanium, zirconium and nitrogen, in amounts of at least 0.1 percent or 0.2 percent by weight. Although at low casting temperatures, these additions or additives do refine the grain, they substantially impair mechanical properties, especially elongation and notch-impact strength.
Manganese steels ~Hadfield type) usually have a carbon content of 0.7 percent to 1.7 percent by weight, with a manganese content of between 5 percent by weight and 18 percent by weight. A carbon : manganese ratio of between 1 : 4 and 1 : 14 is also essential if the properties of manganese steels are to be maintained. At lower ratios, austenitic steel is no longer present, the steel can no longer be work-hardened, and toughness is also impaired. At higher ratios, the austenite is too stable, again there is no work-hardening, and the desired properties are also not obtained.
i s ~ - 5 -122~
A phosp~orus content in excess of 0.1 percent by weight produces an extreme decline in toughness, so that, as is known, a particularly low phosphorus content must be sought.
AST~ A 128/64 describes four different kinds of manganese steel, with the carbon content varying between 0.7 percent by weight and 1.45 percent by weight and the manganese content between 11 percent by weight and 14 percent by weight. The carbon content is varied to alter the degree of work-hardening, and this may also be influenced ky the addition of chromium in amounts of between 1.5 percent by weight and 2.5 percent by weight.
Coarse carbide precipitations are to be avoided by adding up to 2.5 percent by weight of molybdenum. An addition of up to 4.0 percent by weight of nickel is intended to stabilize the austenite, thus preventing the formation of pearlite in thick-walled castings.
Also known is manganese steel containing about 5 percent by weight of manganese. Although such steels have little toughness, they have high resistance to wear.
1~2~i;6~
OBJECTS OF THE INVENTION
_ It is an important object of the present invention to provide a work-hardenable austenitic manganese steel having an eiongation at rupture of 10 percent to 80 percent, -the most uniform possible structure over the entire cross-section, and a particularly fine grain size, with no impairment of mechanical properties.
DETAILED DESCRIPTION OF THE INVENTION
r: . _ _ _ __ _____ The work-hardenable austenitic manganese steel according to the invention, having an elongation at rupture of 10 percent to 80 percent, measured according to L = 5 d or L = 10 d, and the following content in percent by weight:
0.7 to 1.7 C
5.0 to 18.0 Mn 0 to 3.0 Cr 0 to 4.0 Ni 0 to 2.5 Mo 0.1 to 0.9 Si up to 0.1 P
1~:%~
and with the proviso that the carbon : manganese ratio be between ~ : 4 and 1 : 14, comprises, as micro-alloying elements, up to 0.20 percent of titanium, up to 0.05 percent of zirconium and up to 0.05 percent of vanadium, with the proviso that the sum of micro-alloying elements be between 0.002 percent and 0.25 percent by weight.
It came as a complete surprise to find that such small additions of alloying elements refine the grain and simultaneously maintain or increase mechanical properties. It has been found that at high furnace temperaturesr such as 1600C, additions of 0.1 percent by weight or more of the alloying elements result in impairment of the aforesaid mechanical properties, while at lower furnace temperatures such as 1480C the addition of 0.25 percent by weight or more of the alloying elements results in such impairment. No precise explanation for this has as yet been found. Zirconium and vanadium are particularly effective at high casting temperatures.
A still finer grain size is obtained by also adding 0.002 percent by weight to 0.008 percent by weight of boron to the manganese steel.
~2~0 Particularly satisfactory grain refinement is obtained by usiny only 0 01 percent by weight to 0.025 percent by weight of titanium as a micro-alloying el.ement.
If the manganese steel contains from 0.01 percent by weight to 0.05 percent by weigh~ of aluminum, the titanium content can be particularly accurately maintained.
The production of a manganese-steel casting according to the invention, by melting a charge in an electric furnace and adding to the molten metal lime-containing and slag-forming additives, adjusting to the desired analysis, raising the charge to a tapping temperature of 1450C to 1600C, deoxidizing with an element having an affinity for oxygen, and tapping into the casting ladle, consists mainly in that the content of the micro-alloying elements titanium, zirconium and vanadium is adjusted in the casting ladle, the melt being poured at a temperature of between 1420C and 1520C, the casting being cooled down and then heated again to an austenitizing temperature of 980C to 1150, and being then quenched.
Adding the micro-alloying elements in the ladle ensures that the content of the said elements is reproducible. A particular high degree of toughness is ~22~6~
obtained by heating the casting to an austenitizing temperature of 980C to 1150C, followed by quenching.
If after being heated to 1030C to 1150C, the casting is cooled to a temperature of 980C to 1000C and is quenched after the temperature in the casting has equalized, this substantially reduces the tendency oE the casting to crack. Manganese steel has lower heat-conductivity than other steels (only one sixth that of iron), and particular attention must therefore be paid to temperature equalization.
Even in the case of large cross-sections, reliable dissolution of grain-boundary carbides may be achieved, with low power-consumption, by a solution heat-treatment at a temperature of between 1080C and 1100C, after which the temperature is lowered to 980C to 1000C and is equalized. The casting is then quenched.
A casting having particular low internal stress may be obtained by heating it to the austenitizing temperature and then subjecting it alternatingly to coolants of different heat-conductivity. Particularly suitable coolants for this purpose are water and air.
.~
~2X156~
If a casting is removed from the mold at a temperature of between 800C and 1000C, is then placed in a heat-treatment furnace in which the temperature of the casting is equalized, and then is immediately raised to the austeniti~ing temperature, this provides a particularly energy-saving process and at the same time prevents high stresses from building up in the casting and avoids pearlitizing.
The invention is explained hereinafter in greater detail by reference to the following examples:
Example 1:
15 t of manganese steel of the following composition were melted in an arc-furnace:
1.21 percent by weight of carbon; 12.3 percent by weight of manganese; 0.47 percent by weight of silicon;
0.023 percent by weight of phosphorus; 0.45 percent by weight of chromium, and traces of nickel and molybdenum.
The melt was covered with a slag consistiny of 90 percent by weight of limestone and 10 percent by weight of calcium fluoride, after which the melt was adjusted to a tapping temperature of 1520C. Final deoxidizing was then carried out with metallic aluminum. After deoxidizing, the melt ~2~5~C) was tapped into the casting ladle, where the measured temperature was 1460C. The melt was poured into a basic sand casting mold Imagnesite). The casting obtained was a tumbler having a gross weight of 14 t and a net weight of 11 t had walls between 60 mm and 180 mm in thickness. The castin~ was allowed to cool to room temperature, was removed from the mold, and then was heated slowly to 1050C. After a holding period of four hours, the tumbler was quenched in water. The casting thus obtained exhibited cracks which had to be closed by welding with the same type of material. The metallographic tests showed an extreme transcrystallite zone with an adjacent globulitic zone.
Test pieces from the said globulitic zone showed 8.4 percent elongation, as measured according to L = 10 d.
Tensile strength was 623 N/mm .
The procedure was the same as in Example 1, titanium in the form of ferro-titanium being added in the casting ladle. The casting ladle was moved to the mold and pouring was carried out at 1460C. ~he casting was cooled and then heated to 1100C, being held at this temperature for four hours. The temperature of the furnace was then lowered to 1000C. Temperature-equalization was obtained in the casting after one hour, after which the casting was ~2~ 3 cooled by alternating immersion in a bath of water The tumbler thus obtained was free from cracks. Metallographic investigation revealed a completely uniform fine-grained structure, except at the edge zone which was microcrystalline. The average titanium-content of the casting was 0.02 percent by weight. Samples taken from the center and edge or the casting showed almost identical mechanical properties, the tensile strength being 820 and 830 N/mm , respectively, and the elongation 40 percent and 43 percent, respectively.
Example 3:
For the purpose of producing a 180 Kg drop-forged striking hammer, with trunnions, for a rock-crushing mill, an ingot similar to that in Example 2 was cast. This ingot was divided and the parts were converted into striking hammers at a forging temperature of 1050C. In the vicinity of the trunnions, these hammers exhibited a completely fine structure which was maintained even after solution heat-treatment and quenching. A hammer produced with the alloy according to Example 1 showed coarse-grained crystals in the vicinity of the trunnions, resulting in some micro-cracks.
X~i6~3 Example 4:
10 t of manganese steel of the ~ollowing composition were melted in an arc-furnace:
1.0 percent by weight of carbon; 5.2 percent by weight of manganese; 0.4 percent by weight of silicon; 1.7 percent by weight of chromium; 1.0 percent by weight of molybdenum, and 0.03 percent by weight of phosphorus. The melt was covered with a slag consisting of 90 percent by weight of limestone and 10 percent by weight of calcium fluoride, and the melt was adjusted to a tapping temperature of 1490C. Final deoxidizing was then carried out with metallic aluminum. After deoxidizlng, the melt was tapped into the casting ladle where the measured temperature was 1430C. Ferro-titanium and a zircon-vanadium alloy were added to the melt in the casting ladle. During the casting of plates for ball-mills, a temperature of 1430C was maintained. The plates obtained had walls 80 mm in thic~ness. They were removed from the mold at a temperature of 850C and were held for two hours in a heat-treatment furnace adjusted to a temperature of 850C until the temperature had equalized. Thereafter, the said plates were heated to 1100C and were then cooled.
Metallographic investigation revealed a completely uniform fine-grained structure except for the edge-zone, which was .5~
microcrystalline. The average content of titanium, vanadium and zirconium was 0.03 percent by weight. The mechanical properties of samples taken from the edges and centers were almost identical, the tensile strength being 850 and 835 N/mm2~ respectively, and the elongation 45 percent and 48 percent, respectively.
Example 5:
The procedure was as in Example 2, but boron as well as tltanium were added in the casting ladle. The temperature pattern was as in Example 2. The casting had an average titanium content of 0.02 percent by weight and an average boron content of 0.005 percent by weight. In the case of samples taken from similar locations, micrographs showed 50 grains in the samples containing titanium only and an average of 60 grains in samples also containing boron, the reduction in average grain-size being from 0.02 mm to 0.017 mm.
Example 6:
500 kg of manganese steel of the following composition were melted in an induction furnace:
122i56~
1.35 percent by weight of carbon; 17.2 percent by weight of manganese; traces of nickel and chromium, and 0.02 percent by weight of phosphorus. The melt was covered with a slag consisting of 90 percent by weight of limestone and 10 percent by weight of calcium fluoride and was adjusted to a tapping temperature of 1600C. Final deoxidizing was carried out with metallic aluminum, after which the melt was tapped into the casting ladle and titanium was added. Round bars 110 mm in diameter were then cast at 1520C. Upon cooling, the bars were removed from the molds, were heated to 1030C, and were held at this temperature for five hours. The furnace-temperature was then lowered to 980C, at which it was held for an hour and a half. The bars were then quenched in a bath of water.
The melts were repeated with varying titanium contents, the mechanical values given in the following table being measured on test-pieces taken from the centers and edge-zones:
~156~
cer.ter test-pieces edge test-pieces tensile elongation tensile elongation % by weight streng~h at rupture streng~h at rupture of titanium N/mm % N/mm %
0.2 550 7.8 710 22 0.1 580 9~2 705 21 0.04 790 42 810 45 0.02 ~12 50 ~25 55 0.01 815 52 830 58 As may be gathered from the table, the addltion of 0.1 percent by weight of titanium at the indicated high furnace temperature produced impairment of mechanical properties and also a relatively large difference between edge and center test-pieces. With a titanium content of less than 0.05 percent by weight, the properties of edge and center test-pieces are almost identical and there is an increase in mechanical properties as compared with non-micro-alloy manganese steel.
Tensile strength and elongation at rupture were determined in accordance with DIN 5 D 145/1975.
Example 7:
500 kg of manganese steel of the following composition were melted in an induction furnace:
~:2~S~
1.35 percent by weight of carbon; 17.2 percent by weight of manganese; -traces of nickel and chromium, and 0,02 percent by weight of phosphorus. The melt was covered with slag. The temperature of the melt rose to a temperature or 1480C at most. For final deoxidation metallic aluminum was added, whereafter the melt was -tapped into the casting ladle and 0.2 percent by weight titanium were added. Round bars 110 mm in diameter were then cast at 1440C. Upon cooling, the bars were removed from the molds, heated to 1030C and held at this temperature for five hours. The furnace temperature was then lowered to 980C and held there for an hour and a half. The bars were subsequently quenched in a bath of water.
Example ~:
500 kg of manganese steel of the following composition were melted in an induction furnace:
1.24 percent by weight of carbon, 0.52 percent by weight of silicon, 12.57 percent by weight of manganese, 0.13 percent by weight of nickel, 0.42 percent by weight of chromium, 0.027 percent by weight of phosphorus and 0.008 percent by weight of sulfur. The melt was covered with slag and adjusted to a tapping temperature of 1470C. For fina~l deoxidation metallic aluminum was added whereafter ~2~i5~
the melt was tapped into the casting ladle and 0.05 percent by weight of titanium was added. The melt temperature was kept always below 1490C. Round bars 110 mm in diameter were then cast at 1440C. Upon cooling, the bars were removed from the molds, heated to 1030C and held at this temperature for five hours. The furnace temperature was then lowered to 980C, and held there one hour and a half.
The bars were then quenched in a bath of water.
Example 9 500 kg of manganese steel were melted in an induction furnace. The procedure was basically the same as in Example 8, however, 0.10 percent by weight of titanium was added into the casting ladle.
_xample 10:
500 kg of manganese steel were melted in an induction furnace. mhe procedure was basically the same as in Example 8, however, 0.18 percent by weight of titanium was added into the casting ladle.
~ ~215~
Example 11-._ 500 kg of manganese steel of the same composition as in ~xample 10 were melted in an induction furnace and cast from the casting ladle at a casting temperature of 1460C.
Example 12:
500 kg of manganese steel of the same composition as in Example 9 were melted in an induction furnace and tapped into the casting ladle at a tapping temperature of 1550.
Example ~3:
500 kg of manganese steel of the following composition were melted in an induction furnace:
1.24 percent by weight of carbon, 0.52 percent by weight of silicon, 12.57 percent by weight of manganese, 0.13 percent by weight of nickel/ 0.42 percent by weight of chromium, 0.027 percent by weight of phosphorus and 0.008 percent by weight of sulfur. The melt was covered with slag and adjusted to a tapping temperature of 1550C. For ~L~2~S~
final deoxidation ~etallic aluminum was added and thereafter O.G5 percent by weight of vanadium.
Subsequently the melt was tapped into the casting ladle and 0.10 percent by weight of titanium was added. The melt temperat~lre was kept always below 1490C. Round bars llo mm in diameter were then cast at 1440C. Upon cooling, the bars were removed from the molds, heated to 1030C and held at this temperature for five hours. The furnace temperature was then lowered to 980C and held there for one hour and a half. The bars were then quenched in a bath of water.
Example 14:
500 kg of manganese steel having the same composition as in Example 13 were melted in an induction furnace and the procedures were the same as in Example 13 with the exception of the tapping temperature of the furnace being adjusted to 1520C.
Example 15:
500 kg of manganese steel having the same composition as in Example 13 were melted in an induction furnace and the procedures were the same as in Example 13 with the exception of the tapping temperature of the furnace being adjusted to 1520C and with the further 1~21~
exception that the bars were cast at a casting temperature o~ 1475C.
Example 16:
500 kg of manganese steel were melted in an induction ~urnace as in Example 8 wlth the exception that the maxinlum temperature of the melt was 1500C, that 0.035 percent by weight of vanadium was added in the furnace and that 0.08 percent by weight of titanium were added in the casting ladle.
Example 17:
500 kg of manganese steel of the following composition were melted in an induction furnace:
1.24 percent by weight of carbon, 0.52 percent by weight of silicon 12.57 percent by weight of manganese, 0.13 percent by weight of nickel, 0.42 percent by weight cf chromium, 0.027 percent by weight of phosphorus, and 0.008 percent by weight of sulfur. At first, however, only 90 percent by weight of the required manganese content were added in the furnace and the melt was heated to a temperature of 1620C. Thereafter the melt was cooled by argon ~lushing to a temperature of 1520C and the remaining ~Z~5~
10 percent by weight of the total manganese content was added. The melt was covered with slag and adjusted to a tapping temperature of 1470C. For final deoxidation metallic aluminum was added and thereafter 0.035 percent by weight of vanaclium. The melt was then tapped into the casting ladle and 0.08 percent by weight of titanium was added. The melt temperature was kept always below 1490C.
Round bars 110 mm in diameter were then cast at a casting temperature of 1460C. Upon cooling, the bars were removed from the molds, heated to 1030C and held at this temperature for five hours. The furnace temperature was then lowered to 980C and held there for one hour and a half. The bars were then quenched in a bath of water.
Example 18:
500 kg of manganese steel of the composition as in Example 17 were melted with the same procedures as in Example 17 with the exception that the vanadium was added into the casting ladle and not in the induction furnace.
The grain size of the vanadium was in the range of 1/8 to 1/4 inch.
~;~2~5SO
Example 19:
500 kg of manganese steel of the composition as in Example 9, with the exception that in addition to the titanium there was added 0.02 percent by weiyht of ~irconium, were melted in an induction furnace under the same procedures as in Example 9.
In the following table the tensile strength and the elongation at rupture are shown for center test pieces and edge test pieces in accordance with examples with examples 7-19.
TABLE
center test-pieces edge test-pieces tensile elongation tensile elongation Example stren~th at rupture stren~th at rupture N/mm % N/mm %
13 648 1~ 695 20 1~ 794 43 804 45 ~2%~56~
As shown by the table a synergisti.c effect occurs with respect to the titanium content and the temperature program or excursion of the melt ! 50 that an improvement in properties only can be obtained when distinct values for the ti-tanium and vanadium content are observed as well as distinct values of the different temperatures.
deformation even under low mechanical stress. Another major disadvantage is that the process re~uires a considerable amount of energy.
Fox these reasons, attempts have already been made to achieve grain refining by adding further alloying elements, for example chromium, titanium, zirconium and nitrogen, in amounts of at least 0.1 percent or 0.2 percent by weight. Although at low casting temperatures, these additions or additives do refine the grain, they substantially impair mechanical properties, especially elongation and notch-impact strength.
Manganese steels ~Hadfield type) usually have a carbon content of 0.7 percent to 1.7 percent by weight, with a manganese content of between 5 percent by weight and 18 percent by weight. A carbon : manganese ratio of between 1 : 4 and 1 : 14 is also essential if the properties of manganese steels are to be maintained. At lower ratios, austenitic steel is no longer present, the steel can no longer be work-hardened, and toughness is also impaired. At higher ratios, the austenite is too stable, again there is no work-hardening, and the desired properties are also not obtained.
i s ~ - 5 -122~
A phosp~orus content in excess of 0.1 percent by weight produces an extreme decline in toughness, so that, as is known, a particularly low phosphorus content must be sought.
AST~ A 128/64 describes four different kinds of manganese steel, with the carbon content varying between 0.7 percent by weight and 1.45 percent by weight and the manganese content between 11 percent by weight and 14 percent by weight. The carbon content is varied to alter the degree of work-hardening, and this may also be influenced ky the addition of chromium in amounts of between 1.5 percent by weight and 2.5 percent by weight.
Coarse carbide precipitations are to be avoided by adding up to 2.5 percent by weight of molybdenum. An addition of up to 4.0 percent by weight of nickel is intended to stabilize the austenite, thus preventing the formation of pearlite in thick-walled castings.
Also known is manganese steel containing about 5 percent by weight of manganese. Although such steels have little toughness, they have high resistance to wear.
1~2~i;6~
OBJECTS OF THE INVENTION
_ It is an important object of the present invention to provide a work-hardenable austenitic manganese steel having an eiongation at rupture of 10 percent to 80 percent, -the most uniform possible structure over the entire cross-section, and a particularly fine grain size, with no impairment of mechanical properties.
DETAILED DESCRIPTION OF THE INVENTION
r: . _ _ _ __ _____ The work-hardenable austenitic manganese steel according to the invention, having an elongation at rupture of 10 percent to 80 percent, measured according to L = 5 d or L = 10 d, and the following content in percent by weight:
0.7 to 1.7 C
5.0 to 18.0 Mn 0 to 3.0 Cr 0 to 4.0 Ni 0 to 2.5 Mo 0.1 to 0.9 Si up to 0.1 P
1~:%~
and with the proviso that the carbon : manganese ratio be between ~ : 4 and 1 : 14, comprises, as micro-alloying elements, up to 0.20 percent of titanium, up to 0.05 percent of zirconium and up to 0.05 percent of vanadium, with the proviso that the sum of micro-alloying elements be between 0.002 percent and 0.25 percent by weight.
It came as a complete surprise to find that such small additions of alloying elements refine the grain and simultaneously maintain or increase mechanical properties. It has been found that at high furnace temperaturesr such as 1600C, additions of 0.1 percent by weight or more of the alloying elements result in impairment of the aforesaid mechanical properties, while at lower furnace temperatures such as 1480C the addition of 0.25 percent by weight or more of the alloying elements results in such impairment. No precise explanation for this has as yet been found. Zirconium and vanadium are particularly effective at high casting temperatures.
A still finer grain size is obtained by also adding 0.002 percent by weight to 0.008 percent by weight of boron to the manganese steel.
~2~0 Particularly satisfactory grain refinement is obtained by usiny only 0 01 percent by weight to 0.025 percent by weight of titanium as a micro-alloying el.ement.
If the manganese steel contains from 0.01 percent by weight to 0.05 percent by weigh~ of aluminum, the titanium content can be particularly accurately maintained.
The production of a manganese-steel casting according to the invention, by melting a charge in an electric furnace and adding to the molten metal lime-containing and slag-forming additives, adjusting to the desired analysis, raising the charge to a tapping temperature of 1450C to 1600C, deoxidizing with an element having an affinity for oxygen, and tapping into the casting ladle, consists mainly in that the content of the micro-alloying elements titanium, zirconium and vanadium is adjusted in the casting ladle, the melt being poured at a temperature of between 1420C and 1520C, the casting being cooled down and then heated again to an austenitizing temperature of 980C to 1150, and being then quenched.
Adding the micro-alloying elements in the ladle ensures that the content of the said elements is reproducible. A particular high degree of toughness is ~22~6~
obtained by heating the casting to an austenitizing temperature of 980C to 1150C, followed by quenching.
If after being heated to 1030C to 1150C, the casting is cooled to a temperature of 980C to 1000C and is quenched after the temperature in the casting has equalized, this substantially reduces the tendency oE the casting to crack. Manganese steel has lower heat-conductivity than other steels (only one sixth that of iron), and particular attention must therefore be paid to temperature equalization.
Even in the case of large cross-sections, reliable dissolution of grain-boundary carbides may be achieved, with low power-consumption, by a solution heat-treatment at a temperature of between 1080C and 1100C, after which the temperature is lowered to 980C to 1000C and is equalized. The casting is then quenched.
A casting having particular low internal stress may be obtained by heating it to the austenitizing temperature and then subjecting it alternatingly to coolants of different heat-conductivity. Particularly suitable coolants for this purpose are water and air.
.~
~2X156~
If a casting is removed from the mold at a temperature of between 800C and 1000C, is then placed in a heat-treatment furnace in which the temperature of the casting is equalized, and then is immediately raised to the austeniti~ing temperature, this provides a particularly energy-saving process and at the same time prevents high stresses from building up in the casting and avoids pearlitizing.
The invention is explained hereinafter in greater detail by reference to the following examples:
Example 1:
15 t of manganese steel of the following composition were melted in an arc-furnace:
1.21 percent by weight of carbon; 12.3 percent by weight of manganese; 0.47 percent by weight of silicon;
0.023 percent by weight of phosphorus; 0.45 percent by weight of chromium, and traces of nickel and molybdenum.
The melt was covered with a slag consistiny of 90 percent by weight of limestone and 10 percent by weight of calcium fluoride, after which the melt was adjusted to a tapping temperature of 1520C. Final deoxidizing was then carried out with metallic aluminum. After deoxidizing, the melt ~2~5~C) was tapped into the casting ladle, where the measured temperature was 1460C. The melt was poured into a basic sand casting mold Imagnesite). The casting obtained was a tumbler having a gross weight of 14 t and a net weight of 11 t had walls between 60 mm and 180 mm in thickness. The castin~ was allowed to cool to room temperature, was removed from the mold, and then was heated slowly to 1050C. After a holding period of four hours, the tumbler was quenched in water. The casting thus obtained exhibited cracks which had to be closed by welding with the same type of material. The metallographic tests showed an extreme transcrystallite zone with an adjacent globulitic zone.
Test pieces from the said globulitic zone showed 8.4 percent elongation, as measured according to L = 10 d.
Tensile strength was 623 N/mm .
The procedure was the same as in Example 1, titanium in the form of ferro-titanium being added in the casting ladle. The casting ladle was moved to the mold and pouring was carried out at 1460C. ~he casting was cooled and then heated to 1100C, being held at this temperature for four hours. The temperature of the furnace was then lowered to 1000C. Temperature-equalization was obtained in the casting after one hour, after which the casting was ~2~ 3 cooled by alternating immersion in a bath of water The tumbler thus obtained was free from cracks. Metallographic investigation revealed a completely uniform fine-grained structure, except at the edge zone which was microcrystalline. The average titanium-content of the casting was 0.02 percent by weight. Samples taken from the center and edge or the casting showed almost identical mechanical properties, the tensile strength being 820 and 830 N/mm , respectively, and the elongation 40 percent and 43 percent, respectively.
Example 3:
For the purpose of producing a 180 Kg drop-forged striking hammer, with trunnions, for a rock-crushing mill, an ingot similar to that in Example 2 was cast. This ingot was divided and the parts were converted into striking hammers at a forging temperature of 1050C. In the vicinity of the trunnions, these hammers exhibited a completely fine structure which was maintained even after solution heat-treatment and quenching. A hammer produced with the alloy according to Example 1 showed coarse-grained crystals in the vicinity of the trunnions, resulting in some micro-cracks.
X~i6~3 Example 4:
10 t of manganese steel of the ~ollowing composition were melted in an arc-furnace:
1.0 percent by weight of carbon; 5.2 percent by weight of manganese; 0.4 percent by weight of silicon; 1.7 percent by weight of chromium; 1.0 percent by weight of molybdenum, and 0.03 percent by weight of phosphorus. The melt was covered with a slag consisting of 90 percent by weight of limestone and 10 percent by weight of calcium fluoride, and the melt was adjusted to a tapping temperature of 1490C. Final deoxidizing was then carried out with metallic aluminum. After deoxidizlng, the melt was tapped into the casting ladle where the measured temperature was 1430C. Ferro-titanium and a zircon-vanadium alloy were added to the melt in the casting ladle. During the casting of plates for ball-mills, a temperature of 1430C was maintained. The plates obtained had walls 80 mm in thic~ness. They were removed from the mold at a temperature of 850C and were held for two hours in a heat-treatment furnace adjusted to a temperature of 850C until the temperature had equalized. Thereafter, the said plates were heated to 1100C and were then cooled.
Metallographic investigation revealed a completely uniform fine-grained structure except for the edge-zone, which was .5~
microcrystalline. The average content of titanium, vanadium and zirconium was 0.03 percent by weight. The mechanical properties of samples taken from the edges and centers were almost identical, the tensile strength being 850 and 835 N/mm2~ respectively, and the elongation 45 percent and 48 percent, respectively.
Example 5:
The procedure was as in Example 2, but boron as well as tltanium were added in the casting ladle. The temperature pattern was as in Example 2. The casting had an average titanium content of 0.02 percent by weight and an average boron content of 0.005 percent by weight. In the case of samples taken from similar locations, micrographs showed 50 grains in the samples containing titanium only and an average of 60 grains in samples also containing boron, the reduction in average grain-size being from 0.02 mm to 0.017 mm.
Example 6:
500 kg of manganese steel of the following composition were melted in an induction furnace:
122i56~
1.35 percent by weight of carbon; 17.2 percent by weight of manganese; traces of nickel and chromium, and 0.02 percent by weight of phosphorus. The melt was covered with a slag consisting of 90 percent by weight of limestone and 10 percent by weight of calcium fluoride and was adjusted to a tapping temperature of 1600C. Final deoxidizing was carried out with metallic aluminum, after which the melt was tapped into the casting ladle and titanium was added. Round bars 110 mm in diameter were then cast at 1520C. Upon cooling, the bars were removed from the molds, were heated to 1030C, and were held at this temperature for five hours. The furnace-temperature was then lowered to 980C, at which it was held for an hour and a half. The bars were then quenched in a bath of water.
The melts were repeated with varying titanium contents, the mechanical values given in the following table being measured on test-pieces taken from the centers and edge-zones:
~156~
cer.ter test-pieces edge test-pieces tensile elongation tensile elongation % by weight streng~h at rupture streng~h at rupture of titanium N/mm % N/mm %
0.2 550 7.8 710 22 0.1 580 9~2 705 21 0.04 790 42 810 45 0.02 ~12 50 ~25 55 0.01 815 52 830 58 As may be gathered from the table, the addltion of 0.1 percent by weight of titanium at the indicated high furnace temperature produced impairment of mechanical properties and also a relatively large difference between edge and center test-pieces. With a titanium content of less than 0.05 percent by weight, the properties of edge and center test-pieces are almost identical and there is an increase in mechanical properties as compared with non-micro-alloy manganese steel.
Tensile strength and elongation at rupture were determined in accordance with DIN 5 D 145/1975.
Example 7:
500 kg of manganese steel of the following composition were melted in an induction furnace:
~:2~S~
1.35 percent by weight of carbon; 17.2 percent by weight of manganese; -traces of nickel and chromium, and 0,02 percent by weight of phosphorus. The melt was covered with slag. The temperature of the melt rose to a temperature or 1480C at most. For final deoxidation metallic aluminum was added, whereafter the melt was -tapped into the casting ladle and 0.2 percent by weight titanium were added. Round bars 110 mm in diameter were then cast at 1440C. Upon cooling, the bars were removed from the molds, heated to 1030C and held at this temperature for five hours. The furnace temperature was then lowered to 980C and held there for an hour and a half. The bars were subsequently quenched in a bath of water.
Example ~:
500 kg of manganese steel of the following composition were melted in an induction furnace:
1.24 percent by weight of carbon, 0.52 percent by weight of silicon, 12.57 percent by weight of manganese, 0.13 percent by weight of nickel, 0.42 percent by weight of chromium, 0.027 percent by weight of phosphorus and 0.008 percent by weight of sulfur. The melt was covered with slag and adjusted to a tapping temperature of 1470C. For fina~l deoxidation metallic aluminum was added whereafter ~2~i5~
the melt was tapped into the casting ladle and 0.05 percent by weight of titanium was added. The melt temperature was kept always below 1490C. Round bars 110 mm in diameter were then cast at 1440C. Upon cooling, the bars were removed from the molds, heated to 1030C and held at this temperature for five hours. The furnace temperature was then lowered to 980C, and held there one hour and a half.
The bars were then quenched in a bath of water.
Example 9 500 kg of manganese steel were melted in an induction furnace. The procedure was basically the same as in Example 8, however, 0.10 percent by weight of titanium was added into the casting ladle.
_xample 10:
500 kg of manganese steel were melted in an induction furnace. mhe procedure was basically the same as in Example 8, however, 0.18 percent by weight of titanium was added into the casting ladle.
~ ~215~
Example 11-._ 500 kg of manganese steel of the same composition as in ~xample 10 were melted in an induction furnace and cast from the casting ladle at a casting temperature of 1460C.
Example 12:
500 kg of manganese steel of the same composition as in Example 9 were melted in an induction furnace and tapped into the casting ladle at a tapping temperature of 1550.
Example ~3:
500 kg of manganese steel of the following composition were melted in an induction furnace:
1.24 percent by weight of carbon, 0.52 percent by weight of silicon, 12.57 percent by weight of manganese, 0.13 percent by weight of nickel/ 0.42 percent by weight of chromium, 0.027 percent by weight of phosphorus and 0.008 percent by weight of sulfur. The melt was covered with slag and adjusted to a tapping temperature of 1550C. For ~L~2~S~
final deoxidation ~etallic aluminum was added and thereafter O.G5 percent by weight of vanadium.
Subsequently the melt was tapped into the casting ladle and 0.10 percent by weight of titanium was added. The melt temperat~lre was kept always below 1490C. Round bars llo mm in diameter were then cast at 1440C. Upon cooling, the bars were removed from the molds, heated to 1030C and held at this temperature for five hours. The furnace temperature was then lowered to 980C and held there for one hour and a half. The bars were then quenched in a bath of water.
Example 14:
500 kg of manganese steel having the same composition as in Example 13 were melted in an induction furnace and the procedures were the same as in Example 13 with the exception of the tapping temperature of the furnace being adjusted to 1520C.
Example 15:
500 kg of manganese steel having the same composition as in Example 13 were melted in an induction furnace and the procedures were the same as in Example 13 with the exception of the tapping temperature of the furnace being adjusted to 1520C and with the further 1~21~
exception that the bars were cast at a casting temperature o~ 1475C.
Example 16:
500 kg of manganese steel were melted in an induction ~urnace as in Example 8 wlth the exception that the maxinlum temperature of the melt was 1500C, that 0.035 percent by weight of vanadium was added in the furnace and that 0.08 percent by weight of titanium were added in the casting ladle.
Example 17:
500 kg of manganese steel of the following composition were melted in an induction furnace:
1.24 percent by weight of carbon, 0.52 percent by weight of silicon 12.57 percent by weight of manganese, 0.13 percent by weight of nickel, 0.42 percent by weight cf chromium, 0.027 percent by weight of phosphorus, and 0.008 percent by weight of sulfur. At first, however, only 90 percent by weight of the required manganese content were added in the furnace and the melt was heated to a temperature of 1620C. Thereafter the melt was cooled by argon ~lushing to a temperature of 1520C and the remaining ~Z~5~
10 percent by weight of the total manganese content was added. The melt was covered with slag and adjusted to a tapping temperature of 1470C. For final deoxidation metallic aluminum was added and thereafter 0.035 percent by weight of vanaclium. The melt was then tapped into the casting ladle and 0.08 percent by weight of titanium was added. The melt temperature was kept always below 1490C.
Round bars 110 mm in diameter were then cast at a casting temperature of 1460C. Upon cooling, the bars were removed from the molds, heated to 1030C and held at this temperature for five hours. The furnace temperature was then lowered to 980C and held there for one hour and a half. The bars were then quenched in a bath of water.
Example 18:
500 kg of manganese steel of the composition as in Example 17 were melted with the same procedures as in Example 17 with the exception that the vanadium was added into the casting ladle and not in the induction furnace.
The grain size of the vanadium was in the range of 1/8 to 1/4 inch.
~;~2~5SO
Example 19:
500 kg of manganese steel of the composition as in Example 9, with the exception that in addition to the titanium there was added 0.02 percent by weiyht of ~irconium, were melted in an induction furnace under the same procedures as in Example 9.
In the following table the tensile strength and the elongation at rupture are shown for center test pieces and edge test pieces in accordance with examples with examples 7-19.
TABLE
center test-pieces edge test-pieces tensile elongation tensile elongation Example stren~th at rupture stren~th at rupture N/mm % N/mm %
13 648 1~ 695 20 1~ 794 43 804 45 ~2%~56~
As shown by the table a synergisti.c effect occurs with respect to the titanium content and the temperature program or excursion of the melt ! 50 that an improvement in properties only can be obtained when distinct values for the ti-tanium and vanadium content are observed as well as distinct values of the different temperatures.
Claims (35)
1. A work-hardenable austenitic manganese steel having an elongation at rupture of 10 percent to 80 percent, as measured according to L = 5 d or L = 10 d, and essentially consisting of, each in percent by weight:
0.7 to 1.7 C
5.0 to 18.0 Mn 0 to 3.0 Cr 0 to 4.0 Ni 0 to 2.5 Mo 0.1 to 0.9 Si up to 0.1 P
0 to 0.008 B
0 to 0.05 Al 0 to 0.05 V
with the proviso that the carbon : manganese ratio is between 1 : 4 and 1 : 14, and containing an amount of micro-alloying elements in percent by weight:
0.0 to 0.05 Ti 0.0 to 0.05 Zr with the proviso that the sum Ti + Zr is in the range of 0.002 percent by weight to 0.05 percent by weight, the remainder iron and impurities arising during the melting process.
0.7 to 1.7 C
5.0 to 18.0 Mn 0 to 3.0 Cr 0 to 4.0 Ni 0 to 2.5 Mo 0.1 to 0.9 Si up to 0.1 P
0 to 0.008 B
0 to 0.05 Al 0 to 0.05 V
with the proviso that the carbon : manganese ratio is between 1 : 4 and 1 : 14, and containing an amount of micro-alloying elements in percent by weight:
0.0 to 0.05 Ti 0.0 to 0.05 Zr with the proviso that the sum Ti + Zr is in the range of 0.002 percent by weight to 0.05 percent by weight, the remainder iron and impurities arising during the melting process.
2. The austenitic manganese steel as defined in claim 1, further including:
boron in the range of 0.002 to 0.008 percent by weight.
boron in the range of 0.002 to 0.008 percent by weight.
3. The austenitic manganese steel as defined in claim 1, further including:
aluminum in the range of 0.01 to 0.05 percent by weight.
aluminum in the range of 0.01 to 0.05 percent by weight.
4. The austenitic manganese steel as defined in claim 1, wherein:
titanium is the only micro-alloying element and is present in the range of 0.01 percent by weight to 0.025 percent by weight.
titanium is the only micro-alloying element and is present in the range of 0.01 percent by weight to 0.025 percent by weight.
5. The austenitic manganese steel as defined in claim 1, further including:
vanadium in the range of 0.01 percent by weight to 0.05 percent by weight with the proviso that the sum of Ti +
Zr + V is in the range of 0.002 percent by weight to 0.05 percent by weight.
vanadium in the range of 0.01 percent by weight to 0.05 percent by weight with the proviso that the sum of Ti +
Zr + V is in the range of 0.002 percent by weight to 0.05 percent by weight.
6. A work-hardenable austenitic manganese steel having an elongation at rupture of 10 percent to 80 percent, as measured according to L = 5 d or L = 10 d, and essentially consisting of, each in percent by weight:
0.7 to 1.7 C
5.0 to 18.0 Mn 0 to 3.0 Cr 0 to 4.0 Ni 0 to 2.5 Mo 0.1 to 0.9 Si up to 0.1 P
0 to 0.05 V
with the proviso that the carbon : manganese ratio is between 1 : 4 and 1 : 14, and containing an amount of micro-alloying elements in percent by weight:
0.0 to 0.2 Ti 0.0 to 0.05 Zr with the proviso that the sum Ti + Zr is in the range of 0.002 percent by weight to 0.25 percent by weight, the remainder iron and impurities arising during the melting process.
0.7 to 1.7 C
5.0 to 18.0 Mn 0 to 3.0 Cr 0 to 4.0 Ni 0 to 2.5 Mo 0.1 to 0.9 Si up to 0.1 P
0 to 0.05 V
with the proviso that the carbon : manganese ratio is between 1 : 4 and 1 : 14, and containing an amount of micro-alloying elements in percent by weight:
0.0 to 0.2 Ti 0.0 to 0.05 Zr with the proviso that the sum Ti + Zr is in the range of 0.002 percent by weight to 0.25 percent by weight, the remainder iron and impurities arising during the melting process.
7. The austenitic manganese steel as defined in claim 6, wherein:
titanium is the only micro-alloying element and is present in the range of 0.01 percent by weight to 0.20 percent by weight.
titanium is the only micro-alloying element and is present in the range of 0.01 percent by weight to 0.20 percent by weight.
8. The austenitic manganese steel as defined in claim 7, further including:
vanadium in the range of 0.01 percent by weight to 0.05 percent by weight with the proviso that the sum of Ti + Zr + V is in the range of 0.002 percent by weight to 0.25 percent by weight.
vanadium in the range of 0.01 percent by weight to 0.05 percent by weight with the proviso that the sum of Ti + Zr + V is in the range of 0.002 percent by weight to 0.25 percent by weight.
9. The austenitic manganese steel as defined in claim 6, wherein:
titanium is present in the range of 0.008 to 0.2 percent by weight.
titanium is present in the range of 0.008 to 0.2 percent by weight.
10. A method for producing a work-hardenable austenitic manganese steel casting or ingot, said method comprising the steps of:
melting a charge in an electric furnace to form a melt;
adding lime-containing and slag-forming additives to said melt;
adjusting said melt for an analysis as given below in percent by weight:
0.7 to 1.7 carbon 5.0 to 18.0 manganese 0.0 to 3.0 chromium 0.0 to 4.0 nickel 0.0 to 2.5 molybdenum 0.1 to 0.9 silicon up to 0.1 phosphorus, the remainder being iron and impurities originating in the melting process and the ratio of carbon to manganese being in the range of 1 : 4 to 1 : 14;
heating said melt to a tapping temperature in the range of 1450°C to 1600°C;
deoxidizing said melt using an element having an affinity for oxygen;
tapping said melt into a casting ladle;
adding to said melt in said casting ladle micro-alloying elements in an amount as given below in percent by weight:
0.0 to 0.05 titanium 0.0 to 0.05 zirconium the sum of the contents of said micro-alloying elements being in the range of 0.002 to 0.05 percent by weight;
casting said melt at a temperature in the range of 1420°C to 1600°C into a mold;
cooling said melt in said mold to form said casting or ingot;
reheating said casting or ingot to an austenitizing temperature in the range of 980°C to 1150°C; and quenching said reheated casting or ingot.
melting a charge in an electric furnace to form a melt;
adding lime-containing and slag-forming additives to said melt;
adjusting said melt for an analysis as given below in percent by weight:
0.7 to 1.7 carbon 5.0 to 18.0 manganese 0.0 to 3.0 chromium 0.0 to 4.0 nickel 0.0 to 2.5 molybdenum 0.1 to 0.9 silicon up to 0.1 phosphorus, the remainder being iron and impurities originating in the melting process and the ratio of carbon to manganese being in the range of 1 : 4 to 1 : 14;
heating said melt to a tapping temperature in the range of 1450°C to 1600°C;
deoxidizing said melt using an element having an affinity for oxygen;
tapping said melt into a casting ladle;
adding to said melt in said casting ladle micro-alloying elements in an amount as given below in percent by weight:
0.0 to 0.05 titanium 0.0 to 0.05 zirconium the sum of the contents of said micro-alloying elements being in the range of 0.002 to 0.05 percent by weight;
casting said melt at a temperature in the range of 1420°C to 1600°C into a mold;
cooling said melt in said mold to form said casting or ingot;
reheating said casting or ingot to an austenitizing temperature in the range of 980°C to 1150°C; and quenching said reheated casting or ingot.
11. The method as defined in claim 10, wherein:
said casting or ingot is reheated to a temperature in the range of 1030°C to 1150°C.
said casting or ingot is reheated to a temperature in the range of 1030°C to 1150°C.
12. The method as defined in claim 11, wherein:
said casting or ingot is reheated to a temperature in the range of 1080°C to 1100°C.
said casting or ingot is reheated to a temperature in the range of 1080°C to 1100°C.
13. The method as defined in claim 11, further including the steps of:
cooling said reheated casting or ingot to a temperature in the range of 980°C to 1000°C; and equalizing said temperature in said casting or ingot.
cooling said reheated casting or ingot to a temperature in the range of 980°C to 1000°C; and equalizing said temperature in said casting or ingot.
14. The method as defined in claim 10, wherein:
said casting or ingot is quenched by alternatingly subjecting the same to coolants of different heat conductivities.
said casting or ingot is quenched by alternatingly subjecting the same to coolants of different heat conductivities.
15. The method as defined in claim 14, wherein:
said alternatingly used coolants are water and air.
said alternatingly used coolants are water and air.
16. The method as defined in claim 10, wherein:
said casting or ingot is cooled in said mold to a temperature in the range of 800° C to 1000° C; and said casting or ingot is removed from said mold and placed in a heat-treating furnace to equalize said temperature.
said casting or ingot is cooled in said mold to a temperature in the range of 800° C to 1000° C; and said casting or ingot is removed from said mold and placed in a heat-treating furnace to equalize said temperature.
17. The method as defined in claim 10, wherein:
additionally adding boron in an amount corresponding to a range of 0.002 to 0.008 percent by weight to said melt in said ladle.
additionally adding boron in an amount corresponding to a range of 0.002 to 0.008 percent by weight to said melt in said ladle.
18. The method as defined in claim 10, further including the step of:
adding aluminum to said melt in an amount corresponding to a range of 0.01 to 0.05 percent by weight.
adding aluminum to said melt in an amount corresponding to a range of 0.01 to 0.05 percent by weight.
19. The method as defined in claim 10, wherein:
titanium is added to said melt in said ladle in an amount corresponding to a range of 0.01 to 0.025 percent by weight.
titanium is added to said melt in said ladle in an amount corresponding to a range of 0.01 to 0.025 percent by weight.
20. The method as defined in claim 10, further including the step of:
adding vanadium in an amount corresponding to a range of 0.01 percent by weight to 0.05 percent by weight with the proviso that the sum of Ti + Zr + V is in the range of 0.002 percent by weight to 0.05 percent by weight.
adding vanadium in an amount corresponding to a range of 0.01 percent by weight to 0.05 percent by weight with the proviso that the sum of Ti + Zr + V is in the range of 0.002 percent by weight to 0.05 percent by weight.
21. A method for producing a work-hardenable austenitic manganese steel casting or ingot, said method comprising the steps of:
melting a charge in an electric furnace to form a melt;
adding slag-forming additives to said melt;
adjusting said melt for an analysis as given below in percent by weight:
0.7 to 1.7 carbon 5.0 to 18.0 manganese 0.0 to 3.0 chromium 0.0 to 4.0 nickel 0.0 to 2.5 molybdenum 0.1 to 0.9 silicon up to 0.1 phosphorus, the remainder being iron and impurities originating in the melting process and the ratio of carbon to manganese being in the range of 1 : 4 to 1 : 14;
heating said melt to a tapping temperature in the range of 1450°C to 1600°C;
deoxidizing said melt using an element having an affinity for oxygen;
tapping said melt into a casting ladle;
adding to said melt in said casting ladle micro-alloying elements in an amount as given below in percent by weight:
0.00 to 0.20 titanium 0.0 to 0.05 zirconium, the sum of the contents of said micro-alloying elements being in the range of 0.002 to 0.25 percent by weight;
casting said melt at a temperature in the range of 1420°C to 1490°C into a mold; and cooling said melt in said mold to form said casting or ingot.
melting a charge in an electric furnace to form a melt;
adding slag-forming additives to said melt;
adjusting said melt for an analysis as given below in percent by weight:
0.7 to 1.7 carbon 5.0 to 18.0 manganese 0.0 to 3.0 chromium 0.0 to 4.0 nickel 0.0 to 2.5 molybdenum 0.1 to 0.9 silicon up to 0.1 phosphorus, the remainder being iron and impurities originating in the melting process and the ratio of carbon to manganese being in the range of 1 : 4 to 1 : 14;
heating said melt to a tapping temperature in the range of 1450°C to 1600°C;
deoxidizing said melt using an element having an affinity for oxygen;
tapping said melt into a casting ladle;
adding to said melt in said casting ladle micro-alloying elements in an amount as given below in percent by weight:
0.00 to 0.20 titanium 0.0 to 0.05 zirconium, the sum of the contents of said micro-alloying elements being in the range of 0.002 to 0.25 percent by weight;
casting said melt at a temperature in the range of 1420°C to 1490°C into a mold; and cooling said melt in said mold to form said casting or ingot.
22. The method as defined in claim 21, wherein:
said melt is heated to a tapping temperature in the range of 1450°C to 1525°C.
said melt is heated to a tapping temperature in the range of 1450°C to 1525°C.
23. The method as defined in claim 21, wherein:
said melt is cast at a temperature in the range of 1420°C to 1460°C into a mold.
said melt is cast at a temperature in the range of 1420°C to 1460°C into a mold.
24. The method as defined in claim 21, further including the steps of:
adding in the range of 2 to 10 percent by weight of the final manganese content to said melt in said electric furnace at a maximum temperature of 1525°C of said melt and thereafter maintaining said melt at a temperature below 1525°C.
adding in the range of 2 to 10 percent by weight of the final manganese content to said melt in said electric furnace at a maximum temperature of 1525°C of said melt and thereafter maintaining said melt at a temperature below 1525°C.
25. The method as defined in claim 21, wherein:
vanadium is added to said melt at a temperature of said melt in the electric furnace in the range of 1490°C to 1525°C after deoxidizing the melt.
vanadium is added to said melt at a temperature of said melt in the electric furnace in the range of 1490°C to 1525°C after deoxidizing the melt.
26. The method as defined in claim 21, wherein:
vanadium is added to said melt in said casting ladle at a temperature of said melt in the range of 1490°C to 1525°C.
vanadium is added to said melt in said casting ladle at a temperature of said melt in the range of 1490°C to 1525°C.
27. The method as defined in claim 21, further including the steps of:
reheating said casting or ingot to an austenitizing temperature in the range of 980°C to 1150°C; and then rapidly cooling said casting or ingot.
reheating said casting or ingot to an austenitizing temperature in the range of 980°C to 1150°C; and then rapidly cooling said casting or ingot.
28. The method as defined in claim 21, wherein:
said casting or ingot is reheated to a temperature in the range of 1030°C to 1150°C.
said casting or ingot is reheated to a temperature in the range of 1030°C to 1150°C.
29. The method as defined in claim 21, wherein:
said casting or ingot is reheated to a temperature in the range of 1080°C to 1100°C.
said casting or ingot is reheated to a temperature in the range of 1080°C to 1100°C.
30. The method as defined in claim 21, further including the steps of:
cooling said reheated casting or ingot to a temperature in the range of 980°C to 1000°C; and equalizing said temperature in said casting or ingot.
cooling said reheated casting or ingot to a temperature in the range of 980°C to 1000°C; and equalizing said temperature in said casting or ingot.
31. The method as defined in claim 21, wherein:
said casting ingot is quenched by alternatingly subjecting the same to coolants of different heat conductivities.
said casting ingot is quenched by alternatingly subjecting the same to coolants of different heat conductivities.
32. The method as defined in claim 21, wherein:
said alternatingly used coolants are water and air.
said alternatingly used coolants are water and air.
33. The method as defined in claim 21, wherein:
said casting or ingot is cooled in said mold to a temperature in the range of 800°C to 1000°C; and said casting or ingot is removed from said mold and placed in a heat-treating furnace to equalize said temperature.
said casting or ingot is cooled in said mold to a temperature in the range of 800°C to 1000°C; and said casting or ingot is removed from said mold and placed in a heat-treating furnace to equalize said temperature.
34. The method as defined in claim 21, further including the step of:
adding vanadium in an amount corresponding to a range of 0.01 percent by weight to 0.05 percent by weight with the proviso that the sum of Ti + V is in the range of 0.01 percent by weight to 0.25 percent by weight.
adding vanadium in an amount corresponding to a range of 0.01 percent by weight to 0.05 percent by weight with the proviso that the sum of Ti + V is in the range of 0.01 percent by weight to 0.25 percent by weight.
35. The method as defined in claim 21, wherein:
titanium is added to said melt in said casting ladle in an amount in the range of 0.008 to 0.2 percent by weight.
titanium is added to said melt in said casting ladle in an amount in the range of 0.008 to 0.2 percent by weight.
Priority Applications (9)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000439018A CA1221560A (en) | 1983-10-14 | 1983-10-14 | Work-hardenable austenitic manganese steel and method for the production thereof |
| AU33060/84A AU575344B2 (en) | 1983-10-14 | 1984-09-14 | Work-hardenable austenitic managanese steel |
| ZA847371A ZA847371B (en) | 1983-10-14 | 1984-09-19 | Work-hardenable austenitic manganese steel and method for the production thereof |
| KR1019840005850A KR850003907A (en) | 1983-10-14 | 1984-09-24 | Work hardenable austenitic manganese steel and its manufacturing method |
| NO844007A NO163289C (en) | 1983-10-14 | 1984-10-05 | PROCEDURAL TEA FOR PREPARING A COLD-DRY NITANIC LANGUAGE L. |
| ES536710A ES536710A0 (en) | 1983-10-14 | 1984-10-11 | A METHOD OF MANUFACTURING A CASTING PIECE OR ROOF OF AUSTENITIC MANGANESE STEEL, HARDENABLE BY MECHANICAL MEANS |
| EP84890187A EP0141804B1 (en) | 1983-10-14 | 1984-10-11 | Hadfield type manganese steel and process for the manufacture thereof |
| PH31331A PH21553A (en) | 1983-10-14 | 1984-10-12 | Work - hardenable austenitic manganese steel and method for the production thereof |
| JP59212755A JPS6096750A (en) | 1983-10-14 | 1984-10-12 | Process-hardenable austenite manganese steel and manufacture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000439018A CA1221560A (en) | 1983-10-14 | 1983-10-14 | Work-hardenable austenitic manganese steel and method for the production thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1221560A true CA1221560A (en) | 1987-05-12 |
Family
ID=4126274
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000439018A Expired CA1221560A (en) | 1983-10-14 | 1983-10-14 | Work-hardenable austenitic manganese steel and method for the production thereof |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0141804B1 (en) |
| JP (1) | JPS6096750A (en) |
| KR (1) | KR850003907A (en) |
| AU (1) | AU575344B2 (en) |
| CA (1) | CA1221560A (en) |
| ES (1) | ES536710A0 (en) |
| NO (1) | NO163289C (en) |
| PH (1) | PH21553A (en) |
| ZA (1) | ZA847371B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT390806B (en) * | 1983-09-23 | 1990-07-10 | Kos Bernd | AUSTENITIC MANGANIC STEEL AND METHOD FOR THE PRODUCTION THEREOF |
| FR2795754B1 (en) * | 1999-07-02 | 2004-10-08 | Thyssen Schienen Technik Gmbh | STEEL RAILWAY RAIL HAVING IMPROVED CHARACTERISTICS, IN PARTICULAR NEEDLE POINT RAIL, AND METHOD FOR MANUFACTURING SUCH A RAIL |
| US6572713B2 (en) * | 2000-10-19 | 2003-06-03 | The Frog Switch And Manufacturing Company | Grain-refined austenitic manganese steel casting having microadditions of vanadium and titanium and method of manufacturing |
| KR100852497B1 (en) * | 2007-03-12 | 2008-08-18 | 한양대학교 산학협력단 | Fe based alloy having corrosion resistance and abrasion resistance and preparation method thereof |
| TWI450973B (en) * | 2011-05-19 | 2014-09-01 | China Steel Corp | Steel making process |
| CN103498108A (en) * | 2013-10-22 | 2014-01-08 | 江苏盛伟模具材料有限公司 | High-boron high-chromium low-carbon wear-resisting alloy steel with good red hardness and manufacturing method thereof |
| CN103498107A (en) * | 2013-10-22 | 2014-01-08 | 江苏盛伟模具材料有限公司 | High-boron high-chromium low-carbon high-temperature-resistant wear-resisting alloy steel and manufacturing method thereof |
| CN103572166A (en) * | 2013-10-22 | 2014-02-12 | 江苏盛伟模具材料有限公司 | Boracic high-speed steel with good red hardness and preparation method thereof |
| CN103540855A (en) * | 2013-10-25 | 2014-01-29 | 丁家伟 | High-toughness high-boron medium-chrome low-carbon wear-resisting alloy steel and preparation method thereof |
| KR102145761B1 (en) * | 2019-01-03 | 2020-08-19 | (주)영신특수강 | High manganese casting alloy steel for crusher and manufacturing method thereof |
| CN113088809B (en) * | 2021-02-26 | 2022-04-05 | 舞阳钢铁有限责任公司 | BTW wear-resistant steel plate and production method thereof |
| CN113444985B (en) * | 2021-05-24 | 2022-10-21 | 北京中永业科技有限公司 | Steel material and preparation method thereof |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1187023A (en) * | 1966-05-09 | 1970-04-08 | Hadfields Ltd | Improvements in Wear-Resisting Steel. |
| SU322399A1 (en) * | 1970-07-03 | 1971-11-30 | ||
| SU610879A1 (en) * | 1976-05-24 | 1978-06-15 | Уральский научно-исследовательский институт черных металлов | Steel |
| SU581165A1 (en) * | 1976-06-16 | 1977-11-25 | Уральский научно-исследовательский институт черных металлов | Wear-resistant steel |
| GB1546282A (en) * | 1977-09-06 | 1979-05-23 | Raufoss Ammunisjonsfabrikker | Austenitic wear-restistant steel |
| AT390806B (en) * | 1983-09-23 | 1990-07-10 | Kos Bernd | AUSTENITIC MANGANIC STEEL AND METHOD FOR THE PRODUCTION THEREOF |
-
1983
- 1983-10-14 CA CA000439018A patent/CA1221560A/en not_active Expired
-
1984
- 1984-09-14 AU AU33060/84A patent/AU575344B2/en not_active Ceased
- 1984-09-19 ZA ZA847371A patent/ZA847371B/en unknown
- 1984-09-24 KR KR1019840005850A patent/KR850003907A/en not_active Application Discontinuation
- 1984-10-05 NO NO844007A patent/NO163289C/en unknown
- 1984-10-11 EP EP84890187A patent/EP0141804B1/en not_active Expired
- 1984-10-11 ES ES536710A patent/ES536710A0/en active Granted
- 1984-10-12 JP JP59212755A patent/JPS6096750A/en active Pending
- 1984-10-12 PH PH31331A patent/PH21553A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| EP0141804B1 (en) | 1988-04-27 |
| ES8506361A1 (en) | 1985-07-01 |
| PH21553A (en) | 1987-12-11 |
| AU575344B2 (en) | 1988-07-28 |
| ZA847371B (en) | 1985-05-29 |
| ES536710A0 (en) | 1985-07-01 |
| KR850003907A (en) | 1985-06-29 |
| NO163289B (en) | 1990-01-22 |
| EP0141804A1 (en) | 1985-05-15 |
| NO844007L (en) | 1985-04-15 |
| NO163289C (en) | 1990-05-02 |
| AU3306084A (en) | 1985-04-18 |
| JPS6096750A (en) | 1985-05-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4531974A (en) | Work-hardenable austenitic manganese steel and method for the production thereof | |
| CA1221560A (en) | Work-hardenable austenitic manganese steel and method for the production thereof | |
| CN109023119A (en) | A kind of abrasion-resistant stee and its manufacturing method with excellent plasticity and toughness | |
| CA2353407C (en) | Method of making an as-rolled multi-purpose weathering steel plate and product therefrom | |
| KR101201647B1 (en) | HIGH Cr CAST IRON ARTICLE WITH SUPERIOR HEAT CRACK RESISTANCE AND METHOD FOR HEAT TREATING HIGH Cr CAST IRON MATERIAL | |
| CN101082097A (en) | High chromium cast iron having excellent fatigue crack resistance and process for producing the same | |
| CN108504959B (en) | A kind of Austenitic Medium Manganese Steel and preparation method thereof of composite alloying processing | |
| CN107881417B (en) | A kind of low yield strength ratio martensite-ferrite-austenite multi-phase wear-resistant steel plate and its manufacturing method | |
| JPS6358881B2 (en) | ||
| US3132937A (en) | Cast steel | |
| JP3545963B2 (en) | High toughness super wear resistant cast steel and method for producing the same | |
| WO2000046416A1 (en) | Method of making a weathering grade plate and product therefrom | |
| US2324322A (en) | High quality cast iron | |
| CA1232780A (en) | Work-hardenable austenitic manganese steel and method for the production thereof | |
| US3193384A (en) | Iron aluminium alloys | |
| US7445750B1 (en) | Reinforced durable steel, method for the production thereof, method for producing parts made of steel, and parts thus obtained | |
| JP2001158937A (en) | Tool steel for hot working, method for producing same and method for producing tool for hot working | |
| CN108690935B (en) | A kind of high-quality alloy tool steel plate and production method | |
| CN107217212B (en) | A kind of high toughness wear resistant Jaw plate bainitic steel and preparation method thereof | |
| US5439535A (en) | Process for improving strength and plasticity of wear-resistant white irons | |
| KR100260025B1 (en) | The manufacturing method for high durable high chromium cast iron and same product | |
| JPS6056056A (en) | Process-hardenable austenite manganese steel and manufacture | |
| KR900005374B1 (en) | Making process for high tensile strength steel | |
| JPS58185755A (en) | Hardenable austenite high manganese steel and manufacture | |
| Vinter | IMPROVING THE PROPERTIES OF CAST IRON MADE FROM STEEL SCRAP BY TI ALLOYING |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |