US2821760A - Flame heating of metal castings to reduce shrinkage cavities - Google Patents

Flame heating of metal castings to reduce shrinkage cavities Download PDF

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Publication number
US2821760A
US2821760A US630419A US63041956A US2821760A US 2821760 A US2821760 A US 2821760A US 630419 A US630419 A US 630419A US 63041956 A US63041956 A US 63041956A US 2821760 A US2821760 A US 2821760A
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Prior art keywords
casting
flame
ingot
feet per
oxy
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Expired - Lifetime
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US630419A
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English (en)
Inventor
Edward F Kurzinski
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Union Carbide Corp
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Union Carbide Corp
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Publication date
Priority to LU35658D priority Critical patent/LU35658A1/xx
Priority to LU31951D priority patent/LU31951A1/xx
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Priority to US630419A priority patent/US2821760A/en
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Publication of US2821760A publication Critical patent/US2821760A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/04—Influencing the temperature of the metal, e.g. by heating or cooling the mould
    • B22D27/06—Heating the top discard of ingots

Definitions

  • Ca s l s- 1 1 i a is i ama sss isa shsat n iw t ai s i i In -.3. h lls s asst as ihsitt ts s t a asl s tmalt he wate c lin of 'a-bufner is' undesirable for s evera l reasons.
  • the flame when the gas velocity is 500 feet per.- ,second :the flame will not burn in the free atmosphere, but requires the igniting efiect of a hot body to keep it burning.
  • the point at which the flame starts to burn varies dependentlupgn th velocity f th s lss bl m tu l t s sl st a be w en he nozzle and the top of the metal casting.
  • the oxy-fuel gas mixture shouldfiow at acalc'ulated discharge velocity (quantity of gas flowing/total area of orifice greater than 2.00 feet per second as it leaves the burner nozzle, and the ratio of oxygen :to;fue1"gas in the mixture should. be maintained betyveen-1,31a11d-L8 to 1.
  • Fig. 2 is an enlarged avertical sectional view of the 1. 2am and par q lhl vbw f l 1Q I -i g-- 1 Pi is an elevationalaview.of thec-bur ner as seen 1ow., niEig-.
  • v is; pei'spe'stivst l par al bm se l wavand n sectigmof another type of casting v beingtreated hY-Jhama ss ptth ia s t m-- vA l svt 31s Bi, 1 t m-inse .sm s -l isa uia men sectional seismi -1min: ha in aan intg raLannu-mr cat liarq sis -i thlana t E11 a ihssafi ls wi h mqlte is't s 4 9a st WiF Wt Q-hQ -QQM After filling the mold a burner 19 has been p laced ip position with its burner noz z1e-; ;21 above the aperture 16 and the top surface of the casting 15.
  • EFh'e two gases mixintimatelytogether within thebpdy- 23 and the resulting combustible mix ture passes through-the burner to the nozzle "21; from which it is discharged through a pluralityof ports -33 against the casting 15.
  • the rnixer body 23 may include an .ssnt at ena son rust saz a .iswsl ulsaq n in Umpir s s tstnpl a shown and sssr hss iin t t d S atqsP tsm 2942 4 1- Ih .pt s iati 9 the oxy en o ti ts saw int e 99m: v t bl mix ur .i d ermin d b a us n .theisstti s o the Prsssut r ula q ,27a d 31: Th 11 92 vel c tyiro V pip e.
  • Partially covering the top of the casting 15, as by the annular cover 14, reduces gas consumption considerably over the amount consumed when no cover is used, the saving in gas being as much as 50% in some instances.
  • a long and narrow casting 41 is treated with two groups of blow-01f flames 43 and 45 projected simultaneously from a pair of nozzles 47 and 49 connected to a single pipe 51 which is supplied with a combustible mixture from a mixer body (not shown) similar to the mixer body 23 shown in Fig. l.
  • the top of the ingot was flat and no shrinkage cavities extended down into the main body of the ingot. Also, the burner was in reusable condition after conclusion of the treatment.
  • Example 1 A partially covered ingot of stainless steel Weighing 3 tons and having a rectangular top 15 x 28 inches and having a hot-top containing 5 inches depth of metal, in contrast to the conventional 8 inches, was treated with a blow-01f flame for 1 hour while holding a non-watercooled burner nozzle 4 inches from the surface of the metal.
  • the blow-off flame was formed by discharging from the burner nozzle at 500 feet per second a 1.53:1 ratio combustible mixture formed from oxygen and natural gas flowing at 827 and 540 cubic feet per hour, respectively.
  • Example 2 A partially covered ingot of nickel-molybdenum tool steel weighing 4500 pounds and having a cylindrical top 19 inches in diameter was provided with a hot-top onehalf the depth normally used on such ingots. The ingot then was treated with a blow-01f flame for 1 hour while holding a non-water-cooled burner nozzle 8 /2 inches from the surface of the metal. The blow-01f flame was formed by discharging from the burner nozzle at 500 feet per second a 1.52:1 ratio combustible mixture formed from oxygen and natural gas flowing at 500 and 333 cubic feet per hour, respectively.
  • Example 3 A partially covered ingot of carbon steel weighing 9000 pounds and having a rectangular top 22 x 25 inches was treatedwith blow-off flames from two nozzles for 65 minutes while holding the two non-water-cooled nozzles 12 inches from the surface of the metal in the hot-top.
  • the blow-0E flames were formed by discharging from both burner nozzles at 500 feet per second a 1.821 ratio combustible mixture formed from oxygen and natural gas flowing at 975 and 540 cubic feet per hour, respectively.
  • the overall yield of usable steel was 85%, in contrast to 76% obtained without treatment.
  • Example 4 A partially covered ingot of chromium-moylbdenumvanadium tool steel was poured with a hot-top constituting 7 /z% of the ingot volume, in contrast to 15% in normal practice. The casting then was treated with a cluster of blow-ofl. flames for 14 minutes from a burner nozzle positioned 4 inches above the metal surface. The time was formed by burning a combustible mixture flow- 4 ing at 300 feet per second, and formed from 300 cubic feet per hour of oxygen and 200 cubic feet per hour of natural gas (a 1.521 ratio).
  • Example 5 An ingot of stainless steel weighing 7360 pounds and having a rectangular top 16 x 31 inches was treated with a blow-off flame for 50 minutes from a burner nozzle positioned 2 /2 inches above the metal surface while leaving the hot-top uncovered. The hot-top had been filled with 390 pounds less metal than usual. The flame was formed by burning a combustible mixture flowing at 500 feet per second, and formed from 1194 and 667 cubic feet per hour, respectively, of oxygen and fuel gas.
  • Example 6 An ingot of stainless steel weighing 6340 pounds and having a rectangular top 15 x 28 inches was poured with an uncovered hot-top and the surface of the metal was covered with silica. A blow-off flame was then applied to the top of the casting for 50 minutes from a burner nozzle located 3 /2 inches above the top. Oxygen and fuel gas were supplied at 923 and 660 cubic feet per hour, respectively, and the mixture flowed at a velocity of 500 feet per second.
  • the slags can be naturally-occurring materials such as Wollastonite or specially prepared synthetics such as dis-
  • the advantages of using slags are: They eliminate depletion of readily oxidizable elements in the steel. They permit heating with higher oxy-fuel gas ratios and thereby take advantage of higher flame temperatures. They permit successful hot-topping of large size ingots.
  • the primary purpose of the slag is to prevent oxidation of elements which may cause porosity in the hot-top--the major element being carbon.
  • Many alloy steels can be hot-topped using oxy-fuel gas flames in these smaller ingot sizes without requiring slags as barriers.
  • the oxy-natural gas ratio would have to be reduced to 1.1 :1 to overcome the effect of oxidation by the combustion products.
  • Using this ratio there is insufficient heat in the combustion products to eifectively hot-top the ingot.
  • the difliculty is caused by the appearance of a powdery slag being formed on the surface of the metal in the hot-top as the heating progresses.
  • This powdery slag probably contains considerable amounts of chromium oxide which is highly refractory.
  • the refractory character of this sl-ag causes considerable heat reflection which substantially decreases the amount of heat made available to the metal in the hot-top.
  • On type 321 stainless an equally unsatisfactory condition is experienced; however, this slag has a slushy character.
  • exothermic materials In treating ingots under production conditions, it is desirable in some cases to add exothermic materials to the synthetic slags.
  • the exothermic material imparts heat to the hot-top surface to retard solidification until the teeming ladle is moved sufliciently for the heating tips to be positioned over the ingots.
  • Example 7 15 x 28 in., 6350 lb. ingot of type 430 stainless was heating using 928 cu. ft. per hour oxygen and 660 cu. ft. per hour of natural gas and the blowoflf flame technique. The heating time was 50 minutes. Using slags, the top crop was 4.1 percent while for conventional practice ingots, the top crop was 10 percent. Oxy-natural gas hot-topping would not have been possible using this ratio on this ingot size without the use of slag.
  • Example 8 22 x 25 in., 7000 lb. ingot of type 304 stainless steel was heating using 1640 cu. ft. per hour of oxygen, 480 cu. ft. per hour of propane, glass slag and blowotf flame. Ingot yield was 88 percent including top crop, bottom crop and scale loss. The regular cast ingot made for comparative purposes showed a yield of 80 percent.
  • the improvement which comprises in combination therewith positioning a burner nozzle above the top surface of said casting and vertically spaced therefrom a distance such that overheating of the nozzle is avoided, and applying from said burner nozzle against said top surface an oxy-fuel gas mixture having an oxygen-to-fuel gas ratio of from 1.321 to 1.811 for natural gas, 2.5:1 to 4.0:1 for propane and 05:1 to 1.1:1 for coke oven and city gas and a velocity of from 200 feet per second to 1000 feet per second, to burn said mixture with a stable blow-off flame by continuous ignition thereof by the molten casting.
  • the improvement which comprises in combination therewith introducing slag on the surface of the hot-top to overcome the effect of oxidation by the combustion products and prevent reflection by refractory oxides, positioning a burner nozzle above the top surface of said casting and vertically spaced therefrom a distance such that overheating of the nozzle is avoided, and applying from said burner nozzle against said top surface an oxy-fuel gas mixture having an oxygen-tofuel gas ratio of from 1.311 to 1.8:1 for natural gas, 2.5:1 to 4.021 for propane and 0.5 :1 to 1.121 for coke oven and city gas and a velocity of from 200 feet per second to 1000 feet per second, to burn said mixture with a stable blow-off flame by continuous ignition thereof by the molten casting.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
US630419A 1956-12-24 1956-12-24 Flame heating of metal castings to reduce shrinkage cavities Expired - Lifetime US2821760A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
LU35658D LU35658A1 (enrdf_load_stackoverflow) 1956-12-24
LU31951D LU31951A1 (enrdf_load_stackoverflow) 1956-12-24
US630419A US2821760A (en) 1956-12-24 1956-12-24 Flame heating of metal castings to reduce shrinkage cavities

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4045536A (en) * 1975-07-08 1977-08-30 Ppg Industries, Inc. Method of casting bismuth, silicon and silicon alloys
US4147750A (en) * 1978-07-24 1979-04-03 Bristol-Myers Company Method for eliminating shrinkage cavities in cast cosmetic sticks and similar products
US4382838A (en) * 1975-02-28 1983-05-10 Wacker-Chemie Gmbh Novel silicon crystals and process for their preparation
US4402492A (en) * 1982-06-16 1983-09-06 United States Steel Corporation Burner apparatus for molten metal fume suppression
US5515903A (en) * 1995-06-19 1996-05-14 Multi-Products, Incorporated Method of making a mold

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US359974A (en) * 1887-03-22 Apparatus for the production of sound castings
US1310072A (en) * 1919-07-15 Field
US1336234A (en) * 1919-07-21 1920-04-06 Frank L Jamison Ingot-casting device
US1671253A (en) * 1926-04-29 1928-05-29 Parsons Casting of ingots
US1763047A (en) * 1927-10-28 1930-06-10 Surface Comb Company Inc Method of burning explosive gaseous mixtures
US1874341A (en) * 1927-11-08 1932-08-30 Osthoff Walter Process of burning heavy oils
US1986201A (en) * 1930-03-12 1935-01-01 Lyman C Huff Method of effecting combustion of fluid fuel
US2116096A (en) * 1938-05-03 Method of burning gas
US2116671A (en) * 1934-10-26 1938-05-10 Rca Corp Cathode ray oscillograph
US2353657A (en) * 1942-01-29 1944-07-18 Linde Air Prod Co Treatment of castings
US2638159A (en) * 1948-11-26 1953-05-12 Nat Cylinder Gas Co Post-mix, multiple outlet gas burner

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US359974A (en) * 1887-03-22 Apparatus for the production of sound castings
US1310072A (en) * 1919-07-15 Field
US2116096A (en) * 1938-05-03 Method of burning gas
US1336234A (en) * 1919-07-21 1920-04-06 Frank L Jamison Ingot-casting device
US1671253A (en) * 1926-04-29 1928-05-29 Parsons Casting of ingots
US1763047A (en) * 1927-10-28 1930-06-10 Surface Comb Company Inc Method of burning explosive gaseous mixtures
US1874341A (en) * 1927-11-08 1932-08-30 Osthoff Walter Process of burning heavy oils
US1986201A (en) * 1930-03-12 1935-01-01 Lyman C Huff Method of effecting combustion of fluid fuel
US2116671A (en) * 1934-10-26 1938-05-10 Rca Corp Cathode ray oscillograph
US2353657A (en) * 1942-01-29 1944-07-18 Linde Air Prod Co Treatment of castings
US2638159A (en) * 1948-11-26 1953-05-12 Nat Cylinder Gas Co Post-mix, multiple outlet gas burner

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4382838A (en) * 1975-02-28 1983-05-10 Wacker-Chemie Gmbh Novel silicon crystals and process for their preparation
US4045536A (en) * 1975-07-08 1977-08-30 Ppg Industries, Inc. Method of casting bismuth, silicon and silicon alloys
US4147750A (en) * 1978-07-24 1979-04-03 Bristol-Myers Company Method for eliminating shrinkage cavities in cast cosmetic sticks and similar products
US4402492A (en) * 1982-06-16 1983-09-06 United States Steel Corporation Burner apparatus for molten metal fume suppression
US5515903A (en) * 1995-06-19 1996-05-14 Multi-Products, Incorporated Method of making a mold

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LU31951A1 (enrdf_load_stackoverflow)
LU35658A1 (enrdf_load_stackoverflow)

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