Abstract: A composition and apparatus and method for aqueous spray conditioning of scale on metal surfaces. An aqueous solution having a base composition of an alkali metal hydroxide is used. The aqueous solution may contain additives to improve the performance of the salt. In one embodiment, the solution is used to condition the scale on a strip of stainless steel. The strip of steel is at a temperature between the melting point of the alkali metal hydroxide in anhydrous form and a temperature at which the Leidenfrost effect appears. One or more nozzles is provided to spray the solution, and the heated strip is passed by the nozzle or nozzles where the solution is sprayed on the surface or surfaces of the strip that have the scale or oxide. The invention also includes the apparatus and control thereof for the spraying of the solution.

Abstract: A composition for nitrocarburizing stainless steel parts and a method for producing a nitride or hard case on such parts using the composition, are provided. The composition includes alkali metal cyanate and alkali metal carbonate, wherein the cyanate ion is present in a weight percentage of greater than 45% and less than 55.2%. The composition is fused and maintained between about 750° F. and about 950° F. depending upon the type of stainless steel to be treated. The workpiece is immersed in the fused bath and left in until a satisfactory compound layer or case is formed. With austenitic stainless steel, the piece is immersed from about four hours to about six hours at temperatures between about 750° F. and about 950° F., preferably between 750° F. and 850° F. to maintain corrosion resistance.

Abstract: A composition for nitrocarburizing stainless steel parts and a method for producing a nitride or hard case on such parts using the composition, are provided. The composition includes alkali metal cyanate and alkali metal carbonate, wherein the cyanate ion is present in a weight percentage of greater than 45% and less than 55.2%. The composition is fused and maintained between about 750° F. and about 950° F. depending upon the type of stainless steel to be treated. The workpiece is immersed in the fused bath and left in until a satisfactory compound layer or case is formed. With austenitic stainless steel, the piece is immersed from about four hours to about six hours at temperatures between about 750° F. and about 950° F., preferably between 750° F. and 850° F. to maintain corrosion resistance. With 400 series stainless steel, increased corrosion resistance is achieved by immersion for between four and six hours at 950° F.

Abstract: A method and composition for removing organic coatings or residues from a substrate is provided, which composition includes an organic carrier of ethanolamines and non-ionic alkylphenol ethoxylate surfactants and mixtures thereof and potassium hydroxide and being free of water.

Abstract: A composition for nitrocarburizing stainless steel parts and a method for producing a nitride or hard case on such parts using the composition, are provided. The composition includes alkali metal cyanate and alkali metal carbonate, wherein the cyanate ion is present in a weight percentage of greater than 45% and less than 55.2%. The composition is fused and maintained between about 750° F. and about 950° F. depending upon the type of stainless steel to be treated. The workpiece is immersed in the fused bath and left in until a satisfactory compound layer or case is formed. With austenitic stainless steel, the piece is immersed from about four hours to about six hours at temperatures between about 750° F. and about 950° F., preferably between 750° F. and 850° F. to maintain corrosion resistance.

Abstract: A composition and apparatus and method of using the composition for aqueous spray descaling or conditioning of scale or oxide on metal surfaces, especially stainless steel strip or the like, in one embodiment, although it can be used to descale or condition oxide or scale on other work pieces such as metal bar, or even discrete objects. An aqueous solution having a base composition of an alkali metal hydroxide, such as sodium hydroxide, potassium hydroxide, or a mixture of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide is used. The aqueous solution may contain certain additives to improve the descaling performance of the salt. In one embodiment, the solution is used to condition the scale or surface oxide on a strip of stainless steel. The strip of steel is at a temperature between the melting point of the alkali metal hydroxide in anhydrous form and a temperature at which the Leidenfrost effect appears.

Abstract: A composition and apparatus and method of using the composition for aqueous spray descaling or conditioning of scale or oxide on metal surfaces, especially stainless steel strip or the like, in one embodiment, although it can be used to descale or condition oxide or scale on other work pieces such as metal bar, or even discrete objects. An aqueous solution having a base composition of an alkali metal hydroxide, such as sodium hydroxide, potassium hydroxide, or a mixture of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide is used. The aqueous solution may contain certain additives to improve the descaling performance of the salt. In one embodiment, the solution is used to condition the scale or surface oxide on a strip of stainless steel. The strip of steel is at a temperature between the melting point of the alkali metal hydroxide in anhydrous form and a temperature at which the Leidenfrost effect appears.

Abstract: A method of removing Cr.sup.+6 from a solution is provided. In removing the Cr.sup.+6, an effective amount of an alkali metal dithionite is added to the solution to reduce substantially all of the Cr.sup.+6 to Cr.sup.+3. A soluble material is provided in the solution which will form a precipitate. Further, the soluble material is selected such that it will coprecipitate and tie up any dissolved or colloidal Cr.sup.+3 formed as a result of the reduction of the Cr.sup.+6. In one embodiment, the solution is alkaline and preferably, the pH of the solution is reduced sufficiently such that the soluble material will quickly precipitate and form the coprecipitate material with the Cr.sup.+3. Thereafter, the solution is filtered to remove the coprecipitated material from the solution and thereby form a supernatant solution suitable for waste discharge which has substantially lowered chromium values. The precipitate has the Cr.sup.+3 tied up in an insoluble non-leachable form.

Abstract: According to the present invention a saturated aqueous solution comprising at least one alkali metal hydroxide and at least one alkali metal nitrate is provided which can be spray added to a fused anhydrous bath which contains alkali metal materials.

Abstract: A method and apparatus is disclosed for prevention of clogging of exhaust systems, especially the exhaust hoods and ducts above fused salt baths onto which salts splatter as they are being added by spraying from aqueous solutions. A fluid tight jacket surrounds a portion of the exhaust pipe and hood and a cooling fluid, preferably the aqueous solution of the salt being added is flowed through the jacket. This will condense the water of the solvent onto the inside of the hood and duct dissolving and washing away any splattered salt.

Abstract: A method and composition is disclosed for removing oxide film from metals and alloys and for detersification of objects. The composition is at least a 1% aqueous solution of gluconic acid or its alkali metal including ammonium salts, citric acid or its alkali metal including ammonium salts, and tartaric acid or its alkali metal including ammonium salts, at least one of these materials being acid in sufficient strength to provide a pH of 4 or less. Also, preferably a non-ionic surfactant is included.