Beryllium copper alloy corner material recycling smelting method

Abstract

The application provides a beryllium copper alloy leftover material recycling and smelting method, and belongs to the technical field of alloy material recycling. The method comprises the following steps: performing hot cleaning on beryllium copper alloy leftover material, and then immersing the beryllium copper alloy leftover material in a metal cleaning solution; laying the immersed beryllium copper alloy leftover material on an iron plate to perform steam airing; wrapping the steam aired beryllium copper alloy leftover material, and then sequentially performing pressing and baking; performing small-power gradual large-power baking on a vacuum smelting furnace; loading the baked beryllium copper alloy leftover material block into the baked vacuum smelting furnace to perform primary vacuum smelting, and sequentially performing refining, casting and solidification to obtain a primary alloy ingot; loading the primary alloy ingot into the vacuum smelting furnace to perform secondary vacuum smelting, and sequentially performing refining, casting, solidification and cast ingot peeling to obtain a secondary alloy round ingot. The application realizes high metal yield, high cast ingot quality and reduced environmental pollution.

Description

Technical Field

[0001] This invention belongs to the field of alloy material recycling technology, and particularly relates to a method for recycling and smelting beryllium copper alloy scrap. Background Technology

[0002] Beryllium copper alloys are typical age-hardening precipitation alloys. After solution treatment and aging heat treatment, they possess high strength and elasticity, wear resistance, corrosion resistance, and are non-magnetic and spark-free, making them the "king of elasticity" in the field of materials science for manufacturing elastic components. They are widely used in aerospace, automotive, mobile phone and computer, electronic communications, high-speed bearings, wear-resistant gears, submarine cables, deep-sea exploration equipment, and other industries. Due to their unique properties, they are irreplaceable in certain application areas.

[0003] In the hot and cold working processes of beryllium copper alloy ingots, strips, and bars, a large amount of scrap materials of varying shapes, including oil-containing / emulsion-containing strips, emulsion-containing milling chips, and bar turning chips, are generated. These materials occupy a lot of space and are difficult to manage. In particular, bar turning chips and emulsion-containing milling chips are lightweight, bulky, and contain a large amount of emulsion waste residue. Electrode heads, furnace charge, and residual materials, due to their irregular shapes, varying specifications, oxide layers, oil stains, and water content, make the recycling process more difficult. Furthermore, if the surface oxide layer and oil stains are not completely removed, the metal yield from direct smelting during reuse is low, and there is a serious problem of metal loss. Moreover, a high proportion of additives can cause ingot defects such as porosity, resulting in poor ingot quality and making efficient recycling impossible.

[0004] In the smelting of beryllium copper alloys, conventional methods rely on traditional non-vacuum smelting, which directly uses non-vacuum smelting to recover waste. This process pollutes the environment inside and outside the workshop, and the process is unstable, resulting in problems such as large metal loss, excessive oxidation and slag formation, low yield, poor consistency of alloy chemical composition, high energy consumption, and high production costs.

[0005] The recycling process for copper alloy scraps is complex, requiring cleaning, drying, packaging, separation, and screening, with stringent requirements. Failure to manage this process properly can lead to mixed materials, resulting in substandard ingot composition. The presence of water or oil can cause internal porosity in the ingots, compromising their quality. Because the scraps are loose and have low density, they float on the surface during the recycling and melting process, making them difficult to melt. Their large surface area leads to significant oxidation and high oxygen content in the pores, resulting in severe slag formation. This slag floats at the copper molten metal interface, hindering further melting and resulting in low metal yield and poor ingot quality. Summary of the Invention

[0006] The purpose of this invention is to provide a method for recycling and smelting beryllium copper alloy scraps. This recycling and smelting method achieves high metal yield and high ingot quality while ensuring the uniformity of beryllium copper alloy ingot composition and reducing environmental pollution.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A method for recycling and smelting beryllium copper alloy scrap, the method comprising the following steps:

[0009] Step S1: After hot cleaning the beryllium copper alloy scrap, soak it in a metal cleaning solution for 0.5 to 1.5 hours.

[0010] In step S1, the metal cleaning solution includes phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, anionic surfactant, sodium carbonate, nonionic surfactant, sodium silicate, and water.

[0011] The mass fractions of phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, anionic surfactant, sodium carbonate, nonionic surfactant, sodium silicate, and water are 18–22, 0.8–1.2, 3–5, 3–5, 2.5–3.5, 14–16, 0.8–1.2, and 948–950, respectively.

[0012] Step S2: After soaking in the metal cleaning solution for 0.5 to 1.5 hours, the beryllium copper alloy scraps are laid flat on an iron plate and steam-dried.

[0013] The thickness of the beryllium copper alloy scrap laid flat on the iron plate is less than 100mm;

[0014] Step S3: Wrap the steam-dried beryllium copper alloy scraps and then press and bake them in sequence;

[0015] Step S4: Bake the vacuum melting furnace gradually from low power to high power.

[0016] Step S5: Load the baked beryllium copper alloy scrap into the baked vacuum melting furnace. Increase the power to 175-185kW within 25-35 minutes, then heat the furnace to 1120℃-1280℃ at 175-185kW. Perform vacuum melting for 15-30 minutes at a vacuum degree of less than -0.08MPa. Then, refine, cast and solidify in sequence to obtain a primary alloy ingot.

[0017] Step S6: The primary alloy ingot is loaded into a vacuum melting furnace and heated to 1270℃~1420℃ using a power of 190~200kW. After secondary vacuum melting for 20~40min under a vacuum degree of less than -0.08MPa, the ingot is then refined, cast, solidified, and peeled off to obtain a secondary alloy round ingot.

[0018] Furthermore, in step S1, the beryllium copper alloy scrap includes turning chips, milling chips, saw chips, and waste strip.

[0019] Furthermore, in step S1, the specific implementation process of the thermal cleaning is as follows:

[0020] The beryllium copper alloy scraps are cleaned with hot water at 90-100℃ and then soaked in hot water at 90-100℃ for 0.5-1.5 hours.

[0021] Furthermore, in step S1, the anionic surfactant is polyacrylamide;

[0022] The nonionic surfactant is an alkylphenol polyoxyethylene ether;

[0023] In step S2, the thickness of the beryllium copper alloy scrap laid flat on the iron plate is 85-95 mm.

[0024] Furthermore, in step S2, a steam pipe carrying steam at 90-110°C is laid under the iron plate.

[0025] During the steam drying process, the leaves should be turned over every 0.5 to 1.5 hours, 7 to 9 times a day, and dried for at least 3 days.

[0026] Furthermore, in step S3, the baking temperature is 170–230°C, and the baking time is 5–7 hours.

[0027] Furthermore, in step S4, the process of gradually increasing the baking power from low to high specifically involves:

[0028] First, use 22-28kW and bake for 13-17 hours; then use 53-57kW and bake for 6-12 hours; finally, use 103-116kW and bake for 6-10 hours.

[0029] Furthermore, in step S5, the refining temperature is 1140℃~1280℃, and the time is 17~27min; the casting temperature is 1070℃~1230℃.

[0030] In step S6, the refining temperature is 1320℃~1430℃ and the time is 23~36min; the casting temperature is 1220℃~1360℃.

[0031] Furthermore, during the casting process, after subcontracting, straw ash is used to cover the entire liquid surface before finally casting it into a graphite mold.

[0032] In summary, the technical solution of the present invention has the following beneficial effects:

[0033] This invention removes surface oxides and oil stains from beryllium copper alloy scraps through thermal cleaning using a metal cleaning solution (including phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, anionic surfactant, sodium carbonate, nonionic surfactant, sodium silicate, and water). This reduces the severity of oxidation and slag formation, prevents slag from floating on the copper molten metal interface, ensures smooth melting, and improves metal yield and ingot quality. Furthermore, by controlling various process conditions such as steam drying, pressing, baking, primary vacuum melting, and secondary vacuum melting, this invention further improves beryllium copper metal yield and ingot quality, reduces scrap accumulation, and achieves efficient recycling of scrap materials. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1:

[0036] Step S1: Raise the water temperature in the cleaning tank to boiling point. Use 95℃ hot water to clean the QBe2.0 beryllium copper alloy scraps, such as the shavings from the round ingot peeling, the shavings from the centerless lathe bar stock, the milling chips from the double-sided milling, and the waste strip, twice. Then soak them in 95℃ hot water for 1 hour, and then add metal cleaning solution and soak for 1 hour to remove surface oxides and oil stains.

[0037] The metal cleaning solution in this embodiment includes phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, polyacrylamide, sodium carbonate, alkylphenol polyoxyethylene ether, sodium silicate, and water, wherein the mass fractions of phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, anionic surfactant, sodium carbonate, nonionic surfactant, sodium silicate, and water are 20, 1, 4, 4, 3, 15, 1, and 949, respectively.

[0038] Step S2: Spread the beryllium copper alloy scraps, after removing surface oxides and oil stains, on an iron plate 10m long and 5m wide, with a thickness of 95mm. Under the iron plate is a steam pipe (the pipe carries 100℃ water steam) for steam drying. During the steam drying process, turn it over every hour, 8 times a day, for 3 days.

[0039] Step S3: Place the steam-dried beryllium copper alloy scraps into a 500-ton briquetting machine, wrap the scraps with waste strip, and press them into high-density blocks 500mm long, 150mm wide, and 150mm high. Place the packaged blocks into a bogie furnace and bake them at 200℃ for 6 hours to remove residual moisture.

[0040] Step S4: Baking the vacuum melting furnace gradually from low power to high power. The specific process of baking gradually from low power to high power is as follows:

[0041] First, bake at 25kW for 15 hours; then bake at 55kW for 9 hours; finally bake at 109kW for 8 hours in the vacuum melting furnace.

[0042] Step S5: The baked beryllium copper alloy scrap blocks are loaded into a baked vacuum melting furnace. The power is increased to 180kW within 30 minutes. The temperature is then raised to 1150℃ at 180kW, followed by vacuum melting for 23 minutes at a vacuum of -0.09MPa. Refining is then carried out at 1210℃ for 22 minutes, followed by slag removal and casting at 1150℃ to obtain a primary alloy ingot. The casting process involves pouring through an intermediate ladle, immediately covering the liquid surface with straw ash after transfer, ensuring complete coverage. Finally, the ingot is poured into a graphite mold measuring 400mm long, 10mm wide, and 8mm high. During the stable melting stage, the melting current, voltage, and melting rate are related to the ingot specifications.

[0043] Step S6: The primary alloy ingot is loaded into a vacuum melting furnace and heated to 1350℃ using a power of 195kW. After secondary vacuum melting for 30 minutes under a vacuum of -0.09MPa, it is refined at 1370℃ for 30 minutes to break the vacuum and remove slag. Then, it is cast at 1290℃ and solidified. The ingot is peeled off to obtain a secondary alloy round ingot.

[0044] The casting process involves pouring through an tundish, immediately covering the molten metal with straw ash after transfer, ensuring complete coverage of the liquid surface. The final casting is a φ190mm, 1m long round ingot. During the stable smelting stage, the smelting current, voltage, and smelting rate depend on the specifications of the ingot being smelted.

[0045] Use a lathe to peel off the outer layer of the secondary smelting ingot until there are no large areas of pores or defects on the surface. Then saw the head and tail of the ingot by about 100-200mm.

[0046] The chemical composition, metal yield, and ingot quality of the beryllium copper alloy recycled and smelted from the beryllium copper alloy scraps in this embodiment are shown in Tables 1 and 2, respectively.

[0047] Example 2:

[0048] Step S1: Raise the water temperature in the cleaning tank to boiling point. Use 100℃ hot water to clean the C17410 beryllium copper alloy scraps, such as the shavings from the peeling of round ingots, the shavings from the centerless lathe bar stock, and the milling chips from double-sided milling, twice. Then soak them in 100℃ hot water for 1.5 hours, and then add metal cleaning solution and soak for 1.5 hours to remove surface oxides and oil stains.

[0049] The metal cleaning solution in this embodiment includes phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, polyacrylamide, sodium carbonate, alkylphenol polyoxyethylene ether, sodium silicate, and water, wherein the mass fractions of phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, anionic surfactant, sodium carbonate, nonionic surfactant, sodium silicate, and water are 22, 1.2, 5, 5, 3.5, 16, 1.2, and 950, respectively.

[0050] Step S2: Spread the beryllium copper alloy scraps, after removing surface oxides and oil stains, on an iron plate 10m long and 5m wide, with a thickness of 90mm. Underneath the iron plate is a steam pipe with multiple through holes (the pipe carries 110℃ water steam) for steam drying. During the steam drying process, turn the scraps over every 1.5 hours, 7 times a day, for 4 days.

[0051] Step S3: Place the steam-dried beryllium copper alloy scraps into a 500-ton briquetting machine, wrap the scraps with waste strip, and press them into high-density blocks 500mm long, 150mm wide, and 150mm high. Place the packaged blocks into a bogie furnace and bake them at 170℃ for 7 hours to remove residual moisture.

[0052] Step S4: Baking the vacuum melting furnace gradually from low power to high power. The specific process of baking gradually from low power to high power is as follows:

[0053] First, bake at 22kW for 13 hours; then bake at 57kW for 12 hours; finally bake at 103kW for 6 hours in the vacuum melting furnace.

[0054] Step S5: The baked beryllium copper alloy scrap blocks are loaded into a baked vacuum melting furnace. The power is increased to 175kW within 25 minutes, and the temperature is raised to 1280℃ at 175kW. Vacuum melting is then performed for 30 minutes under a vacuum of -0.08MPa, followed by refining at 1280℃ for 27 minutes. After slag removal, the ingot is cast at 1230℃ and solidified to obtain a primary alloy ingot. The casting process involves casting through an intermediate ladle, immediately covering the liquid surface with straw ash after transfer, ensuring complete coverage. Finally, the ingot is cast into a graphite mold measuring 400mm long, 10mm wide, and 8mm high. The melting current, voltage, and melting rate during the stable melting stage are related to the ingot specifications.

[0055] Step S6: The primary alloy ingot is loaded into a vacuum melting furnace and heated to 1270℃ using a power of 190kW. After secondary vacuum melting for 40 minutes under a vacuum of -0.08MPa, it is refined at 1430℃ for 36 minutes to break the vacuum and remove slag. Then, it is cast at 1360℃ and solidified. The ingot is peeled off to obtain a secondary alloy round ingot.

[0056] The casting process involves pouring through an tundish, immediately covering the molten metal with straw ash after transfer, ensuring complete coverage of the liquid surface. The final casting is a round ingot with a diameter of 168mm and a length of 1m. During the stable smelting stage, the smelting current, voltage, and smelting rate depend on the specifications of the ingot being smelted.

[0057] Use a lathe to peel off the outer layer of the secondary smelting ingot until there are no large areas of pores or defects on the surface. Then saw the head and tail of the ingot by about 100-200mm.

[0058] The chemical composition, metal yield, and ingot quality of the beryllium copper alloy recycled and smelted from the beryllium copper alloy scraps in this embodiment are shown in Tables 1 and 2, respectively.

[0059] Example 3:

[0060] Step S1: Raise the water temperature in the cleaning tank to boiling point. Use 90℃ hot water to clean the C17410 beryllium copper alloy scraps, such as the shavings from the peeling of round ingots, the shavings from the centerless lathe bar stock, and the milling chips from double-sided milling, three times. Then soak them in 90℃ hot water for 0.5 hours, and then add metal cleaning solution and soak for 0.5 hours to remove surface oxides and oil stains.

[0061] The metal cleaning solution in this embodiment includes phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, polyacrylamide, sodium carbonate, alkylphenol polyoxyethylene ether, sodium silicate, and water, wherein the mass fractions of phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, anionic surfactant, sodium carbonate, nonionic surfactant, sodium silicate, and water are 18, 0.8, 3, 3, 2.5, 14, 0.8, and 948, respectively.

[0062] Step S2: Spread the beryllium copper alloy scraps, after removing surface oxides and oil stains, on an iron plate 10m long and 5m wide, with a thickness of 85mm. Underneath the iron plate is a steam pipe with multiple through holes (the pipe carries 90℃ water steam) for steam drying. During the steam drying process, turn the scraps over every 0.5 hours, 9 times a day, for 5 days.

[0063] Step S3: Place the steam-dried beryllium copper alloy scraps into a 500-ton briquetting machine, wrap the scraps with waste strip, and press them into high-density blocks 500mm long, 150mm wide, and 150mm high. Place the packaged blocks into a bogie furnace and bake them at 230℃ for 5 hours to remove residual moisture.

[0064] Step S4: Baking the vacuum melting furnace gradually from low power to high power. The specific process of baking gradually from low power to high power is as follows:

[0065] First, bake at 28kW for 17 hours; then bake at 53kW for 6 hours; finally bake at 116kW for 10 hours in the vacuum melting furnace.

[0066] Step S5: The baked beryllium copper alloy scrap blocks are loaded into a baked vacuum melting furnace. The power is increased to 185kW within 35 minutes, and the temperature is raised to 1120℃ at 185kW. Vacuum melting is then performed for 30 minutes under a vacuum of -0.08MPa, followed by refining at 1140℃ for 17 minutes. After slag removal and vacuum breaking, the ingot is cast at 1070℃ and solidified to obtain a primary alloy ingot. The casting process involves casting through an intermediate ladle, immediately covering the liquid surface with straw ash after transfer, ensuring complete coverage. Finally, the ingot is cast into a graphite mold measuring 400mm long, 10mm wide, and 8mm high. During the stable melting stage, the melting current, voltage, and melting rate are related to the ingot specifications.

[0067] Step S6: Load the primary alloy ingot into a vacuum melting furnace, heat it to 1420℃ using 200kW power, then perform secondary vacuum melting for 20 minutes under a vacuum of -0.09MPa, refine it at 1320℃ for 23 minutes, break the vacuum and remove slag, then cast it at 1220℃ and solidify it. Peel off the ingot to obtain a secondary alloy round ingot.

[0068] The casting process involves pouring through an tundish, immediately covering the molten metal with straw ash after transfer, ensuring complete coverage of the liquid surface. The final casting is a 1m long, φ166mm round ingot. During the stable smelting stage, the smelting current, voltage, and smelting rate depend on the specifications of the ingot being smelted.

[0069] Use a lathe to peel off the outer layer of the secondary smelting ingot until there are no large areas of pores or defects on the surface. Then saw the head and tail of the ingot by about 100-200mm.

[0070] The chemical composition, metal yield, and ingot quality of the beryllium copper alloy recycled and smelted from the beryllium copper alloy scraps in this embodiment are shown in Tables 1 and 2, respectively.

[0071] Table 1 Chemical composition of Be-Cu alloys recovered and smelted in Examples 1-3

[0072]

[0073]

[0074] Table 2. Yield of recovered Be-Cu metal and ingot quality after smelting in Examples 1-3

[0075]

[0076] As shown in Table 1, the chemical compositions of the different Be-Cu alloys prepared in Examples 1-3 are consistent with those of QBe2.0 and C17410, exhibiting good uniformity. Therefore, the beryllium copper alloy scrap recycling and smelting method of this embodiment can ensure the uniformity of ingot composition. As shown in Table 2, the metal yield of the different Be-Cu alloys prepared in Examples 1-3 is improved, and the ingot quality is also improved. Therefore, the beryllium copper alloy scrap recycling and smelting method of this embodiment can achieve efficient recycling of scrap, with high metal yield and guaranteed ingot quality.

[0077] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for recycling and smelting beryllium copper alloy scrap, characterized in that, The method for recycling and smelting beryllium copper alloy scrap includes the following steps: Step S1: After hot cleaning the beryllium copper alloy scrap, soak it in a metal cleaning solution for 0.5~1.5 hours. In step S1, the metal cleaning solution includes phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, anionic surfactant, sodium carbonate, nonionic surfactant, sodium silicate, and water. The mass fractions of phosphoric acid, sodium tripolyphosphate, sodium benzenesulfonate, anionic surfactant, sodium carbonate, nonionic surfactant, sodium silicate, and water are 18-22, 0.8-1.2, 3-5, 3-5, 2.5-3.5, 14-16, 0.8-1.2, and 948-950, respectively. In step S1, the anionic surfactant is polyacrylamide; The nonionic surfactant is an alkylphenol polyoxyethylene ether; Step S2: After soaking in the metal cleaning solution for 0.5~1.5 hours, the beryllium copper alloy scraps are laid flat on an iron plate and steam-dried. The thickness of the beryllium copper alloy scrap laid flat on the iron plate is less than 100mm; Step S3: Wrap the steam-dried beryllium copper alloy scraps and then press and bake them in sequence; Step S4: Bake the vacuum melting furnace gradually from low power to high power. In step S4, the process of gradually increasing the baking power from low to high specifically involves: First, use 22~28kW and bake for 13~17 hours; then use 53~57kW and bake for 6~12 hours; finally, use 103~116kW and bake for 6~10 hours. Step S5: Load the baked beryllium copper alloy scrap into the baked vacuum melting furnace. Increase the power to 175-185kW within 25-35 minutes, then heat the furnace to 1120℃-1280℃ at 175-185kW. Perform vacuum melting for 15-30 minutes at a vacuum degree of less than -0.08MPa. Then, refine, cast and solidify in sequence to obtain a primary alloy ingot. Step S6: The primary alloy ingot is loaded into a vacuum melting furnace and heated to 1270℃~1420℃ using a power of 190~200kW. After secondary vacuum melting for 20~40 minutes under a vacuum degree of less than -0.08MPa, the ingot is then refined, cast, solidified, and peeled off to obtain a secondary alloy round ingot.

2. The method for recycling and smelting beryllium copper alloy scraps according to claim 1, characterized in that, In step S1, the beryllium copper alloy scrap includes turning chips, milling chips, saw chips, and waste strip.

3. The method for recycling and smelting beryllium copper alloy scraps according to claim 2, characterized in that, In step S1, the specific implementation process of the thermal cleaning is as follows: The beryllium copper alloy scraps are cleaned with hot water at 90-100℃ and then soaked in hot water at 90-100℃ for 0.5-1.5 hours.

4. The method for recycling and smelting beryllium copper alloy scraps according to any one of claims 1 to 3, characterized in that, In step S2, the thickness of the beryllium copper alloy scrap laid flat on the iron plate is 85~95mm.

5. The method for recycling and smelting beryllium copper alloy scraps according to claim 4, characterized in that, In step S2, a steam pipe carrying steam at 90~110℃ is laid under the iron plate; During the steam drying process, the leaves should be turned over every 0.5 to 1.5 hours, 7 to 9 times a day, and dried for at least 3 days.

6. The method for recycling and smelting beryllium copper alloy scraps according to claim 5, characterized in that, In step S3, the baking temperature is 170~230℃ and the baking time is 5~7h.

7. The method for recycling and smelting beryllium copper alloy scraps according to claim 6, characterized in that, In step S5, the refining temperature is 1140℃~1280℃ and the time is 17~27min; the casting temperature is 1070℃~1230℃. In step S6, the refining temperature is 1320℃~1430℃ and the time is 23~36min; the casting temperature is 1220℃~1360℃.

8. The method for recycling and smelting beryllium copper alloy scraps according to claim 7, characterized in that, During the casting process, after subcontracting, straw ash is used to cover the entire liquid surface, and finally it is cast into a graphite mold.

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