A method for carburizing a steel member of the present invention includes: bringing a carburizing agent into contact with at least a part of a surface of a steel member; and heating the steel member and the carburizing agent to allow carbon to penetrate into at least a part of the surface, in which the carburizing agent contains a Fe—C alloy powder, a graphite powder in an amount of 20% by volume or more and 70% by volume or less relative to a total volume of the carburizing agent, and a binder that binds the Fe—C alloy powder and the graphite powder to each other, and in the heating, a heating temperature is held for a certain period of time within a temperature range of an austenite region of a eutectic point of the steel member or higher and lower than the peritectic point of the steel member.

A method for carburizing a steel member of the present invention includes: bringing a carburizing agent into contact with at least a part of a surface of a steel member; and heating the steel member and the carburizing agent to allow carbon to penetrate into at least a part of the surface, in which the carburizing agent contains a Fe—C alloy powder, a graphite powder in an amount of 20% by volume or more and 70% by volume or less relative to a total volume of the carburizing agent, and a binder that binds the Fe—C alloy powder and the graphite powder to each other, and in the heating, a heating temperature is held for a certain period of time within a temperature range of an austenite region of a eutectic point of the steel member or higher and lower than the peritectic point of the steel member.

Development of different inorganic materials, having the capacity to generate visible colors when excited in the infrared region, which can be used to determine the origin of explosives, fuses and ammunition, even after detonation, and in weapons and metal projectiles, thus serving as a safety marking tool thereof. The following were developed: LaNbO.sub.4 (called Mark1), BiVO.sub.4, Sr.sub.3V.sub.2O.sub.8 and YNbO.sub.4 (called Mark2), doped with different rare earth ions (erbium, ytterbium, holmium and thulium). The markers were physically inserted inside the explosives and in the gunpowder and by carburizing and forging in steel or metal alloy, with which the weapon or metal projectile is manufactured. The parameter used to demonstrate the presence of the markers in the products, after detonation or scraping of the weapon, was the verification of the color identity of the marker fluorescence, before and after, via laser in the infrared region.

Development of different inorganic materials, having the capacity to generate visible colors when excited in the infrared region, which can be used to determine the origin of explosives, fuses and ammunition, even after detonation, and in weapons and metal projectiles, thus serving as a safety marking tool thereof. The following were developed: LaNbO.sub.4 (called Mark1), BiVO.sub.4, Sr.sub.3V.sub.2O.sub.8 and YNbO.sub.4 (called Mark2), doped with different rare earth ions (erbium, ytterbium, holmium and thulium). The markers were physically inserted inside the explosives and in the gunpowder and by carburizing and forging in steel or metal alloy, with which the weapon or metal projectile is manufactured. The parameter used to demonstrate the presence of the markers in the products, after detonation or scraping of the weapon, was the verification of the color identity of the marker fluorescence, before and after, via laser in the infrared region.

A process for making full dense components of a carbon-containing steel, comprises the steps of: a) making a powder of the carbon-containing steel by gas atomization wherein the carbon content is low, less than 0.15 wt %, b) agglomerating the powder from step a) with at least one hydrocolloid and elemental carbon, c) compacting the agglomerated powder from step b) to a density of at least 80% of theoretical density, with the proviso that the compacted agglomerated powder still is porous allowing transport of gas to and from its interior, and d) sintering the compacted powder to a density of more than 98% of theoretical density, preferably more than 99% of theoretical density, wherein a gas comprising carbon is added during sintering and finally subjecting the component to HVC. Advantages include that it is possible to manufacture a dense component of powders which otherwise are difficult to compact.

A method for heat treating a steel component, which comprises the steps of: (a) carburizing the steel component with a carbon potential above 1.0, (b) carburizing the steel component with a carbon potential above 0.6, (c) quenching the steep component, and (d) subjecting the steel component to a bainitic treatment.

A method for heat treating a steel component, which comprises the steps of: (a) carburizing the steel component with a carbon potential above 1.0, (b) carburizing the steel component with a carbon potential above 0.6, (c) quenching the steep component, and (d) subjecting the steel component to a bainitic treatment.

A process for obtaining a piston ring may include providing a piston ring of an internal combustion engine and submitting a surface of the piston ring to a laser surface heat treatment. The surface may be a sliding surface of the piston ring. The piston ring may be a one piece piston ring and/or a scrapper ring.

A process for obtaining a piston ring may include providing a piston ring of an internal combustion engine and submitting a surface of the piston ring to a laser surface heat treatment. The surface may be a sliding surface of the piston ring. The piston ring may be a one piece piston ring and/or a scrapper ring.

A carburizer, which effects carburization with respect to molten iron accommodated in an electric furnace or a ladle, includes a mixture of quicklime and a carbon material having an ash content of from 5 mass % to 18 mass %, and satisfies the conditions 0.6≤(mc+Mc)/ms≤2.7 and 0.7≤(mc+Mc)/ma≤6.5. A method of carburization uses this carburizer. Here, mc represents the mass of CaO in the carbon material, ms represents the mass of SiO.sub.2 in the carbon material, ma represents the mass of Al.sub.2O.sub.3 in the carbon material, and Mc represents the mass of the quicklime.