KR920004504B1 - Fuel-oxidant mixtures for explosive gun flame plating and flame plating methods in explosive guns - Google Patents

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Description

Fuel-oxidant mixtures for explosive gun flame plating and flame plating methods in explosive guns

The figure shows RP% vs. RT% for an oxygen-acetylene mixture or an acetylene-second hydrocarbon mixture diluted with nitrogen.

The present invention relates to a novel fuel-oxidant mixture and to a coating layer prepared therefrom for use in an apparatus for flame plating using explosive means, more particularly at least two combustible gases such as acetylene and propylene. To a fuel-oxidant mixture containing them.

Flame plating by means of explosives using D-guns has been used in related industries for more than four quarters to manufacture coatings of various compositions. The explosion gun consists essentially of a fluid-cooled barrel with a small inner diameter of about 1 inch. In general, a mixture of oxygen and acetylene is fed to the gun with the pulverized coating material. The oxygen-acetylene fuel gas mixture is ignited to produce an explosion wave, which travels underneath the explosion gun barr, where it heats the coating material and directs the coating material from the gun to the product to be coated. US Patent No. 2,714,563 discloses a method and apparatus for using explosive waves for spark coating. In this specification, such patents are referred to by reference, as cited in their entirety.

In general, when the fuel gas mixture in the explosion dry ignites, an explosion wave is formed that accelerates the crushed coating material to about 2400 feet one second while the coating material is heated to a temperature near its melting point. A nitrogen pulse cleans the barrel after the coating material exits the barrel of the explosion gun. Typically this cycle is repeated about 4 to 8 times per second. The main control of the explosion coating is obtained by changing the explosion mixture of oxygen to acetylene.

In some applications, such as making tungsten carbide-cobalt based coatings, it has been found that diluting the oxygen-acetylene fuel mixture with an inert gas such as nitrogen or argon may result in an improved coating. It has been found that these gaseous diluents tend to lower or lower the flame temperature because they are independent of the explosion reaction. US Pat. No. 2,972,550 discloses a process for diluting an oxygen-acetylene fuel mixture with an increased number of coating compositions for new and wider applications based on the desired coating and for use in explosive plating processes. This patent is also referred to herein by reference.

In general, acetylene has been used as a combustible fuel gas because it can create higher temperatures and pressures than can be obtained from any other saturated or unsaturated hydrocarbon gas. However, for some cladding applications, the combustion temperature of the oxygen-acetylene mixture of oxygen to carbon ratio of about 1: 2 makes the combustion temperature considerably higher than the desired temperature. As mentioned above, a common way to compensate for the high combustion temperatures of oxygen-acetylene fuel gases is to dilute the fuel gas mixture with an inert gas such as nitrogen or argon. However, this dilution can lower the temperature due to combustion, but this also results in an incidentally lower peak pressure of the combustion reaction. This reduction in peak pressure results in a decrease in the velocity of the coating material emerging from the barrel onto the substrate. It has been found that the peak pressure of the combustion reaction decreases much faster than the combustion temperature as the inert gas diluted in the oxygen-acetylene fuel mixture increases.

It is an object of the present invention to provide a novel gaseous fuel-oxidant mixture for use in explosive guns, which can provide fuel combustion temperatures lower than those obtainable from conventional oxygen-acetylene fuel gases, while at the same time in combustion reactions. To provide a relatively high peak pressure.

Another object of the present invention is to use in an explosion gun, which can provide the same temperature as the fuel combustion temperature obtained from conventional oxygen-acetylene fuel gas diluted with inert gas without damaging the peak pressure in the combustion reaction. To provide a novel gaseous fuel-oxidant mixture for.

Another object of the present invention is to provide a new coating on the base using the novel fuel-oxidant mixture of the present invention.

The above objects and other features of the present invention will be fully appreciated from the following detailed description and embodiments of the present invention.

The present invention relates to a gaseous fuel-oxidant mixture for use in an explosion gun, comprising (a) an oxidant and (b) a fuel mixture of at least two types of combustible gases selected from the group of saturated and unsaturated hydrocarbons.

The present invention also relates to an improved flame plating method using an explosive gun, which method comprises introducing a desired fuel and oxidant gases into the explosive gun to produce an explosive mixture, and into the explosive mixture in the explosive gun. Introducing a pulverized coating material and exploding the fuel-oxidant mixture such that the coating material is coated over the product to be coated, wherein the improvements include at least two selected from the group of saturated hydrocarbons and unsaturated hydrocarbons. A fuel mixture of a combustible gas of a kind and an explosive fuel-oxidant mixture of oxidants. The explosive gun consists of a mixing chamber and a barrel to allow the pulverized coating material to flow into the barrel while the explosive fuel-oxidant mixture enters the mixing and ignition chamber. The ignition of the fuel-oxidant mixture produces an explosive wave that travels under the barrel of the explosive gun, heating the ground cladding there and covering the cladding onto the substrate.

The invention also relates to coated articles made by the novel process of the invention.

The oxidant for use in the present invention may be selected from the group consisting of oxygen, nitrous oxide, mixtures thereof and the like.

In addition, the combustible fuel mixture of at least two kinds of gases for use in the present invention is acetylene (C ₂ H ₂ ), propylene (C ₃ H ₆ ), methane (CH ₄ ), ethylene (C ₂ H ₄ ), methylacetylene (C ₃ H ₄ ), propane (C ₃ H ₈ ), ethane (C ₂ H ₆ ), butadiene (C ₄ H ₆ ), butylene (C ₄ H ₈ ), butane (C ₄ H ₁₀ ), cyclopropane (C ₃ H ₆ ), propadiene (C ₃ H ₄ ), cyclobutane (C ₄ H ₈ ), and ethylene oxide (C ₂ H ₄ O). Preferred fuel mixtures are those consisting of acetylene gas together with at least one other combustible gas such as propylene.

As mentioned above, acetylene is believed to be the best combustible fuel for explosive gun operation, because acetylene can create temperatures and pressures greater than those obtainable from any other saturated or unsaturated hydrocarbon. To reduce the temperature of the reaction product of the combustible gas, nitrogen or argon is usually added to the oxidant-fuel mixture and diluted. However, this method has the disadvantage of limiting the particle velocity that can be obtained by lowering the pressure of the explosion wave. In addition, however, when a second combustible gas such as propylene is mixed with acetylene, the reaction of a suitable oxidant with the combustible gas forms a peak pressure at any temperature, ie the pressure at the same temperature of the acetylene-oxygen mixture diluted with nitrogen. It has been found to form higher pressures. If at any given temperature, the acetylene-oxygen-nitrogen mixture is replaced with an acetylene-second combustible gas-oxygen mixture, the gaseous mixture containing this second combustible gas is always better than the acetylene-oxygen-nitrogen hop mixture. Will create a higher peak pressure.

The theoretical values of RP% and RT% are defined as follows.

RP% 〓100 (P _D / P _O )

RT% 〓100 △ T _D / T _O

Where P _O and ΔT _O represent the pressure and temperature which increase after explosion of the 1: 1 mixture of oxygen and acetylene, respectively, from the following reaction formulae.

C ₂ H ₂ + O ₂ → 2CO + H ₂

In addition, P _D and ΔT _D are increased in pressure and temperature following the explosion of either an oxygen-acetylene mixture or an acetylene-second hydrocarbon gas-oxygen mixture diluted with nitrogen when the carbon to oxygen ratio is 1: 1. Respectively.

In addition, different values are obtained using various values for X or Y in the following equation.

C ₂ H ₂ + O ₂ + XN ₂ = 2CO + H ₂ + XN ₂ (2a)

[1-Y] C ₂ H ₂ + y C _A H _B + [1-y + Ay / 2] O ₂ →

[2-2Y + AY] CO + [1-y + BY / 2] H ₂ (2b)

The values of RP% vs. RT% for the explosion of an oxygen-acetylene mixture or an acetylene-second hydrocarbon-oxygen mixture diluted with nitrogen are shown in the figures. As can be seen from the figure, when N ₂ is added as in Equation 2a to decrease ΔT _D and consequently the RT% value, the peak pressure P _D and consequently the RP% value decreases. For example, if DELTA T _D is reduced to 60% DELTA T _O by adding a sufficient amount of nitrogen, the peak pressure P _D drops to 50% P _O. However, if an acetylene-secondary hydrocarbon-oxygen mixture is used for any value of ΔT _D or RT%, then a larger P _D and consequently RP% value will be obtained than with an acetylene-oxygen mixture diluted with nitrogen. Will get For example, as shown in the figure, when using an acetylene-propylene-oxygen mixture to obtain an RT% value of 60%, the ratio of RP% is 80%, and the acetylene-oxygen-nitrogen mixture is obtained to obtain the same RT% value. 1.6 times larger than when used. It is believed that the high pressure increases the particle velocity, thus improving the coating properties.

In most applications, the gaseous fuel-oxidant mixture of the present invention has an atomic ratio of oxygen to carbon of about 0.9 to 2.0, preferably 0.95 to 1.6, most preferably 0.98 to 1.4. An atomic ratio of oxygen to carbon of less than 0.9 is generally undesirable due to the formation of free carbon and soot, etc., while an atomic ratio of greater than 2.0 will be undesirable for carbides and metallic coatings due to excessive flame oxidation.

The gaseous fuel-oxidant mixture in a preferred embodiment of the present invention consists of 35 to 80 volume percent oxygen, 2 to 50 volume percent acetylene and 2 to 60 volume percent second combustible gaseous fuel. In a more preferred embodiment of the present invention the gaseous fuel-oxidant mixture will consist of 45-70 volume percent oxygen, 7-45 volume percent acetylene and 10-45 volume percent second combustible fuel. In addition, the gaseous fuel-oxidant mixture in another preferred embodiment of the zone invention has a second combustible gaseous fuel such as 50-65 volume percent oxygen, 12-26 volume percent acetylene and 18-30 volume percent propylene. It consists of. For some applications, it is desirable to add an inert diluent gas to the gaseous fuel-oxidant mixture, and suitable inert diluent gases are argon, neon, krypton, xenon, helium and nitrogen.

In general, all prior art coating materials that can be used as prior art fuel-oxidant mixtures in explosive gun applications can be used with the novel gaseous fuel-oxidant mixtures of the present invention. In addition, even when the coating composition of the prior art is applied at a lower temperature and higher pressure than in the prior art, it is possible to form a coating having a conventional composition but having a new physical property such as new hardness and unique properties. Coating compositions suitable for use with the gaseous fuel-oxidant mixtures of the present invention include tungsten carbide-cobalt, tungsten carbide-nickel, tungsten carbide-cobalt chromium, tungsten carbide-nickel chromium, chromium-nickel, aluminium oxide, carbonization Chromium-nickel chromium, chromium carbide-cobalt chromium, tungsten-titanium carbide-nickel, cobalt alloy, cobalt alloy dispersion oxide, alumina-titania, copper base alloy, chromium base alloy, chromium oxide, chromium oxide + aluminum oxide, titanium oxide , Titanium + aluminum oxide, iron base alloy, oxide dispersed in iron base alloy, nickel, nickel base alloy and so on. These unique coating materials are ideally suited for coating substrates made of materials such as titanium, steel, aluminum, nickel, cobalt and their alloys.

Powders used in the D-gun to apply the coatings according to the invention are preferred powders made by casting and grinding processes. In this process, the powder components are melted and cast into a shell ingot, and then the ingot is pulverized into a powder and then sieved to obtain a desired particle size distribution.

However, other types of powders and mixtures of powders, such as sintered powders produced by the sintering process, can also be used. In the sintering process, the constituents of the powder are sintered together with a sinter cake, and the cake is then crushed into powdered water bodies to obtain the desired particle size distribution.

Some embodiments are described below for illustration of the present invention. In these examples the coatings were made using the powder compositions shown in Table 1.

TABLE 1

Coating material powder

* US standard mesh size

Example 1

Each of the gaseous fuel-oxidant mixtures of the composition shown in Table 2 below is introduced into an explosion gun to produce an explosive mixture having an atomic ratio of oxygen to carbon shown in Table 2. Sample coating powder A is also supplied to the explosion gun. The flow rate of each gaseous fuel-oxidant mixture is 13.5 cfm, except that samples 28, 29 and 30 are 11.0 ft ³ / min (cfm), and the feed rate for each coating powder is 46.7 g / min for sample 29 (gpm) and 53.3 gpm, except that sample 30 was 40.0 gpm. The atomic ratio of oxygen to carbon for each coating example and gaseous fuel-mixture in% by volume is shown in Table 2. The coated sample powder is fed to the explosion gun simultaneously with the gaseous fuel-oxidant mixture. Explosive guns ignite at a rate of about eight times per second, causing the coating powders of the blast bombards to collide with the steel base, forming a dense adhesive coating in the form of fine ribs that interlock and overlap with each other.

The weight percent of cobalt and carbon in the coating layer is determined along with the hardness for the coating. The hardness of most coating examples in Table 2 is the value measured by Rockwell surface hardness and changed to Vickers hardness. The Rockwell surface hardness measurement method used here is based on ASTM Standard Method E-18. Hardness measurements were made on the smooth and flat surface of the coating itself deposited on the hardened steel matrix. The following equation was used to convert Rockwell hardness to Vickers hardness.

HV.3〓-1774 + 37.433 HR45N

Where HV.3 is the Bigcus hardness obtained with a load of 0.3 kgf and HR45N is the Rockwell surface hardness obtained on N scale with a diamond cone and 45 kgf load. The hardness of Samples 28,29 and 30 is specified by direct Vickers hardness. The Vickers hardness test used was basically measured by ASTM Standard Method E-384, except that only one diagonal line of square indentation was measured, rather than averaged over both diagonal lengths. The load used was 0.3 kgf (HV.3) and their data are shown in Table 2. As can be seen from this table, the coating obtained by using propylene in the gaseous fuel-mixture instead of nitrogen had excellent hardness.

Erosion is a form of wear in which materials are removed from the surface by the action of colliding particles. These particles are generally solid and carried in a gaseous or fluid stream, while the particles may be a fluid contained in a gaseous stream.

There are many factors that affect wear caused by erosion. Particle size, mass and velocity are important factors because they determine the kinetic energy of the particles they collide with. In addition, the shape of the particles, their hardness, the angle of formation and the shape and their density can affect the erosion rate, the particle collision angle can also affect the erosion rate. In general, alumina and silica powders are widely used for test purposes.

Test procedures similar to those described in ASTMG 76-83 were used to determine the erosion wear rates of the coatings described in the Examples. Basically, about 1.2 gm of alumina abrasive per minute is transported in the gas stream to the nozzle, which is installed on the pivot to allow for a variety of intergranular angles to be maintained at regular intervals. Testing of the cladding at 90 ° and 30 ° impact angles is the standard method.

During the test, the colliding particles create craters on the test sample. The measured groove of the crater is divided by the amount of abrasive impinged on the sample. As a result, the wear as micrometer (μ) per gram of abrasive was taken as the erosion wear rate (μ / gm), and the results are also shown in Table 2.

As hardness and erosion wear data, the use of an acetylene-hydrocarbon gas-oxygen mixture in place of nitrogen diluted acetylene-oxygen mixture has a higher hardness at the same cobalt content (compare sample 9 and sample 22 and 23) or It can be seen that at the same hardness, a coating can be made with a higher cobalt content (compare Sample 1 and Sample 22).

TABLE 2

D-Gun Parameters and Properties of Coatings Made from Powder A

Note (1); Measured as Rockwell surface hardness and converted to Vickers hardness, except as indicated by an asterisk (*).

Example 2

Each of the gaseous fuel-oxidant mixtures of the compositions shown in Table 3 is introduced into the explosion gun at a flow rate of 13.5 ft ³ / min, respectively, to produce an explosive mixture having an atomic ratio of oxygen to carbon as also shown in Table 3. The coating powder was sample A, and the fuel-oxidant mixture and the powder feed rate are also shown in Table 3. As in Example 1, Bigcurs hardness and erosion rate (μ / gm) data were determined and shown in Table 3. As can be seen from this data, various hydrocarbon gases can be used with acetylene to provide a gaseous fuel-oxidant mixture according to the present invention for coating a matrix. As Bigcurs data, the use of an acetylene-hydrocarbon-oxygen mixture instead of an acetylene-oxygen-nitrogen mixture has a higher hardness at the same cobalt content (compare sample coatings 5 and 10 in Table 2 with sample coating 23) or It can be seen that a coating can be made with more cobalt content for the same hardness (compare Samples 6, 8 and 11 in Table 2 with Sample 22).

TABLE 3

D-Gun Parameters and Properties of Coatings Made from Powder A

Sample coating 8 also contains 18.3% by volume of nitrogen.

Example 3

Each of the gaseous fuel-oxidant mixtures of the compositions shown in Table 4 was introduced into the explosion gun to produce an explosive mixture having an atomic ratio of tetracarbons, also shown in Table 4. The coating powder was sample B, and the fuel-oxidant mixture is also shown in Table 4. The gas flow rate is 13.5 ft3 / min (cfm) and the feed rates are shown in Table 4. As in Example 1, hardness and erosion rate (μ / gm) were determined and shown in Table 4. The sintered powder does not show a significant change in the cobalt content with the change in the explosive temperature, but it is possible to obtain a higher hardness coating with the same cobalt content as the acetylene-hydrocarbon-oxygen mixture than the acetylene-oxygen-nitrogen mixture (sample coating 4 and Sample 1).

TABLE 4

D-Gun Parameters and Properties of Coatings Made from Powder B

Example 4

Each of the gaseous fuel-oxidant mixtures of the compositions shown in Table 5 was introduced into an explosion gun to produce an explosive mixture having an atomic ratio of oxygen to carbon, also shown in Table 5. The coating powder was sample C and the fuel-oxidant mixture is also shown in Table 5. The gas flow rate is 13.5 ft3 / min (cfm) and the feed rates are as shown in Table 5. As in Example 1, Bigcurs hardness and erosion rate (μ / gm) were determined and shown in Table 5. From the Vickers hardness data, it can be seen that using an acetylene-hydrocarbon-oxygen mixture instead of an acetylene-oxygen-nitrogen mixture yields a coating with a higher hardness at the same cobalt content (Sample Coating 2 and Sample Coating). Compare 1)

TABLE 5

D-Gun Parameters and Properties of Coatings Made from Powder C

Example 5

Each of the gaseous fuel-oxidant mixtures of the compositions shown in Table 6 was introduced into the explosion gun to produce an explosive mixture having an atomic ratio of oxygen to carbon, also shown in Table 6. The coating powder was sample D, and the fuel-oxidant mixture is also shown in Table 6. The gas flow rate was 13.5 cfm except that sample coatings 17, 18 and 19 were 11.0 ft ³ / min (cfm) and the feed rate was 46.7 g / min (gpm). As in Example 1, Bigcus hardness and bedroom fraction (μ / gm) were determined and these data are shown in Table 6. From this Big Cus hardness data, the use of an acetylene-hydrocarbon-oxygen mixture instead of an acetylene-oxygen-nitrogen mixture has a higher hardness at the same cobalt content (compare Sample Coating 5 and Sample Coating 17) or the same. It can be seen that a coating can be made with a higher cobalt content for hardness (compare Sample 5 and Sample 18).

TABLE 6

D-Gun Parameters and Properties of Coatings Made from Powder D

NOTE (1) Measurements as Rockwell Surface Hardness, converted to Vickers Hardness, except as indicated by an asterisk (*).

There may be other various implementations without departing from the spirit of the invention, and the above-described embodiments are intended to illustrate the invention and are not intended to limit the invention thereto.

Claims (29)

A gaseous fuel-oxidant mixture for use in a foal gun, characterized in that it comprises a) an oxidant and (b) a fuel mixture of at least two combustible gases selected from the group of saturated and unsaturated hydrocarbons. The fuel mixture of claim 1, wherein the fuel mixture is acetylene; Of a second combustible gas selected from the group consisting of propylene, methane, ethylene, methylacetylene, propane, pentane, butadiene, butylene, butane, ethylene oxide, ethane, cyclopropane, propadiene, cyclobutane and mixtures thereof A gaseous fuel-oxidant mixture, characterized in that it consists of a mixture. 3. The gaseous fuel-oxidant mixture according to claim 2, wherein the oxidant is selected from the group consisting of oxygen, nitrogen dioxide and mixtures thereof. 4. The gaseous fuel-oxidant mixture according to claim 3, wherein the mixture has an atomic ratio of oxygen to carbon of 0.9 to 2.0. 5. The gaseous fuel-oxidant mixture according to claim 4, wherein the second combustible gas is selected from the group consisting of propylene, propane and butylene, and the atomic ratio of oxygen to carbon is 0.95 to 1.6. 5. The gaseous fuel-oxidant mixture according to claim 4, wherein the second combustible gas consists of propylene. The gaseous fuel-oxidant mixture according to claim 1, wherein the mixture contains 35 to 80% by volume of oxidant, 2 to 50% by volume of acetylene and 2 to 60% by volume of a second combustible gas. 8. The gaseous fuel-oxidant mixture according to claim 7, wherein the mixture contains 45 to 70 volume percent oxygen, 7 to 45 percent acetylene and 10 to 45 volume percent second combustible gas. 9. The gaseous fuel-oxidant mixture according to claim 8, wherein the mixture contains 50 to 65 volume percent oxygen, 12 to 26 volume percent acetylene and 18 to 30 volume percent second combustible gas. 10. The gaseous fuel-oxidant mixture according to claim 9, wherein the second combustible gas consists of propylene. The gaseous fuel-oxidant mixture according to claim 1, 3 or 4, characterized in that the mixture contains an inert diluent gas. 12. The gaseous fuel-oxidant mixture according to claim 11, wherein the inert diluent gas is selected from the group consisting of argon, neon, krypton, xenon, helium and nitrogen. 13. The gaseous fuel-oxidant mixture according to claim 12, wherein the inert diluent gas is nitrogen. Exploding gun flame plating method comprising the steps of introducing a desired fuel and oxidant gases into the explosion gun to form an explosive mixture, and exploding the fuel-oxidant mixture such that the coating material is coated over the product to be coated. (A) an oxidizing agent; and (b) using an explosive fuel-oxidant mixture of a fuel mixture of at least two combustible gases selected from the group of saturated and unsaturated hydrocarbons. 15. The fuel mixture of claim 14, wherein the oxidant is selected from the group consisting of oxygen, nitrous oxide, and mixtures thereof, wherein the fuel mixture is selected from the group consisting of acetylene; A second combustible gas selected from the group consisting of propylene, methane, ethylene, methylacetylene, propane, pentane, butadiene, butylene, butane, ethylene oxide, ethane, cyclopropane, propadiene, cyclobutane and mixtures thereof Characterized in that it consists of a mixture of these compounds. The method of claim 15 wherein the mixture contains an inert diluent gas. 15. The process of claim 14, wherein the mixture has an atomic ratio of oxygen to carbon of 0.9 to 2.0. 18. The method of claim 17, wherein the second gas is selected from the group consisting of propylene, propane and butylene, wherein the atomic ratio of oxygen to carbon is 0.95 to 1.6. 19. The method of claim 18, wherein the second combustible gas consists of propylene. 16. The process according to claim 15, wherein the mixture contains 45 to 70 volume percent oxidant, 7 to 45 volume percent acetylene and 10 to 45 volume percent second combustible gas. 20. The process of claim 19, wherein the mixture contains 50 to 65 volume percent oxygen, 12 to 26 volume percent acetylene and 18 to 30 volume percent propylene. A method of operating an explosive gun having a mixing and ignition chamber and a barrel, wherein a desired fuel and oxidant gas is introduced into the gun through the mixing and ignition chamber, the crushed coating material is introduced into the barrel, and the product to be coated is coated. A method of operating an explosive gun that explodes a mixture in the gun so as to clasp upwards, the explosive fuel-oxidant mixture of a fuel mixture of (a) an oxidant and (b) at least two combustible gases selected from the group of saturated and unsaturated hydrocarbon gases. Operation method of the explosion gun characterized by using. 22. The method of claim 21, wherein the oxidizing agent is selected from the group consisting of oxygen, nitrous oxide, and mixtures thereof, the fuel mixture comprising acetylene; Of a second combustible gas selected from the group consisting of propylene, methane, ethylene, methylacetylene, propane, pentane, butadiene, butylene, butane, ethylene oxide, ethane, cyclopropane, propadiene, cyclobutane and mixtures thereof Characterized in that it consists of a mixture. The method of claim 23 wherein the mixture contains an inert diluent gas. The method of claim 23, wherein the mixture has an atomic ratio of oxygen to carbon of 0.9 to 2.0. 26. The method of claim 25, wherein the second combustible gas is selected from the group consisting of propane, propylene and butylene, and the atomic ratio of oxygen to carbon is 0.95 to 1.6. 27. The method of claim 26, wherein the second combustible gas consists of propylene. 28. The process of claim 27 wherein the mixture contains 45-70 volume percent oxidant, 7-45 volume percent acetylene and 10-45 volume percent second combustible gas. 28. The process of claim 27 wherein the mixture contains 50-65 volume percent oxygen, 12-26 volume percent acetylene and 18-30 volume percent propylene.

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