The present invention concerns the use of at least one alkane sulfonic acid of formula RSO.sub.3H, in which R represents a linear or branched saturated hydrocarbon chain comprising 1 to 4 carbon atoms, for cleaning solid deposits containing at least one aconitic acid salt. The invention also concerns a method for cleaning solid deposits containing at least one aconitic acid salt, using at least one alkane sulfonic acid.

The present invention concerns the use of at least one alkane sulfonic acid of formula RSO.sub.3H, in which R represents a linear or branched saturated hydrocarbon chain comprising 1 to 4 carbon atoms, for cleaning solid deposits containing at least one aconitic acid salt. The invention also concerns a method for cleaning solid deposits containing at least one aconitic acid salt, using at least one alkane sulfonic acid.

A cleaning composition, and method for use of the cleaning composition to clean metal surfaces, such as the surfaces of turbomachinery components, is presented. For example, a method includes contacting a surface of an article with a cleaning composition, wherein the article comprises a metal and wherein the surface includes an oxide; and removing the cleaning composition from the surface. The cleaning composition has a viscosity of at least 10.sup.4 poise, and comprises a thickening agent and an acidic matrix having selective reactivity with the oxide.

A cleaning composition, and method for use of the cleaning composition to clean metal surfaces, such as the surfaces of turbomachinery components, is presented. For example, a method includes contacting a surface of an article with a cleaning composition, wherein the article comprises a metal and wherein the surface includes an oxide; and removing the cleaning composition from the surface. The cleaning composition has a viscosity of at least 10.sup.4 poise, and comprises a thickening agent and an acidic matrix having selective reactivity with the oxide.

A method of cleaning a turbine engine includes directing a cleaning solution towards a component of the turbine engine having a layer of foreign material thereon, the cleaning solution including water, a first organic acidic component, a second organic acidic component, isopropylamine sulphonate, alcohol ethoxylate, triethanol amine, and sodium lauriminodipropionate. The cleaning solution has a pH between 2.5 and 7.0.

A method of cleaning a turbine engine includes directing a cleaning solution towards a component of the turbine engine having a layer of foreign material thereon, the cleaning solution including water, a first organic acidic component, a second organic acidic component, isopropylamine sulphonate, alcohol ethoxylate, triethanol amine, and sodium lauriminodipropionate. The cleaning solution has a pH between 2.5 and 7.0.

A high-strength hot-dip galvanized steel sheet includes a hot-dip galvanized layer on a surface of the steel sheet and has a specific component composition and a steel microstructure containing, on an area percentage basis, 90% to 100% of martensite and carbide-containing bainite in total and 0% to 10% of retained austenite, and containing prior austenite grains having an aspect ratio of 2.0 or less, in a region extending from 300 m to 400 m from the surface layer, in which the ratio of the average amount of C at 5 m from the surface layer to the average amount of C at 70 m from the surface layer is 0.2 to 0.8, and the ratio of the standard deviation of the amount of C to the average amount of C in a region extending from 300 m to 400 m from the surface layer is 0.40 or less.

A high-strength hot-dip galvanized steel sheet includes a hot-dip galvanized layer on a surface of the steel sheet and has a specific component composition and a steel microstructure containing, on an area percentage basis, 90% to 100% of martensite and carbide-containing bainite in total and 0% to 10% of retained austenite, and containing prior austenite grains having an aspect ratio of 2.0 or less, in a region extending from 300 m to 400 m from the surface layer, in which the ratio of the average amount of C at 5 m from the surface layer to the average amount of C at 70 m from the surface layer is 0.2 to 0.8, and the ratio of the standard deviation of the amount of C to the average amount of C in a region extending from 300 m to 400 m from the surface layer is 0.40 or less.

A method of decontaminating metal surfaces in a cooling system of a nuclear reactor comprises conducting a plurality of treatment cycles, with each of the treatment cycles comprising: an oxidation step wherein metal oxides including radioisotopes on the metal surfaces are contacted with an aqueous solution of a permanganate oxidant; a decontamination step after the oxidation step wherein the metal oxides are contacted with an aqueous solution of an organic acid selected from the group consisting of oxalic acid, formic acid, citric acid, tartaric acid, picolinic acid, gluconic acid, glyoxylic acid and mixtures thereof so as to dissolve at least part of the metal oxides and the radioisotopes; and a cleaning step wherein at least the radioisotopes are immobilized on an ion exchange resin; wherein the oxidation step comprises at least one acidic oxidation step and at least one alkaline oxidation step carried out one after another in either the same or different treatment cycles; and wherein the plurality of treatment cycles comprises at least one treatment cycle including a high temperature oxidation step, wherein the permanganate oxidant solution is kept at a temperature of at least 100 C. and, wherein the at least one reactor coolant pump is used to circulate and heat the oxidation solution inside the primary loop, and the residual heat removal system is used to control the temperature of the oxidant solution during the high temperature oxidation step.

A method of decontaminating metal surfaces in a cooling system of a nuclear reactor comprises conducting a plurality of treatment cycles, with each of the treatment cycles comprising: an oxidation step wherein metal oxides including radioisotopes on the metal surfaces are contacted with an aqueous solution of a permanganate oxidant; a decontamination step after the oxidation step wherein the metal oxides are contacted with an aqueous solution of an organic acid selected from the group consisting of oxalic acid, formic acid, citric acid, tartaric acid, picolinic acid, gluconic acid, glyoxylic acid and mixtures thereof so as to dissolve at least part of the metal oxides and the radioisotopes; and a cleaning step wherein at least the radioisotopes are immobilized on an ion exchange resin; wherein the oxidation step comprises at least one acidic oxidation step and at least one alkaline oxidation step carried out one after another in either the same or different treatment cycles; and wherein the plurality of treatment cycles comprises at least one treatment cycle including a high temperature oxidation step, wherein the permanganate oxidant solution is kept at a temperature of at least 100 C. and, wherein the at least one reactor coolant pump is used to circulate and heat the oxidation solution inside the primary loop, and the residual heat removal system is used to control the temperature of the oxidant solution during the high temperature oxidation step.