A process for the production of steel with increased ductility in which a sulfur-containing steel melt is deoxidized and, if desired, is supplied with alloying elements, the deoxidized melt is treated with calcium as part of a purification action simultaneously reducing the sulfur content and the reaction is carried out in a casting ladle having a lining free from siliceous oxides. The melt is covered with a synthetic slag free from siliceous oxides and the calcium-containing substance is introduced in fine-grain particulate form into the melt in a carrier gas at a level at least 2000 mm below the melt surface and at a rate which is less than the maximum rate at which the calcium-containing substance is capable of reacting with the melt.
The present invention relates to a refining agent used for deoxidation, desulfurization, and dephosphorization of molten steel by a ladle refining, as well as methods for producing such a refining agent. The general practice in ladle refining is to use for the refining agent both so-called flux, which is mainly composed of CaO, and a Ca-based metallic additive. In conventional practice, the flux and the Ca-based metallic additive are added to the molten steel separately. It is an object of the present invention to provide a refining agent, wherein the flux and metallic CaO component act highly effectively on the molten metal. A refining agent for metal according to the present invention essentially consists of: a Ca alloy, which essentially consists of Ca and at least one element selected from the group consisting of Al and Si, and a flux mainly composed of CaO and Al.sub.2 O.sub.3, the Ca-alloy phases and the flux phases being integrally bonded to one another. According to the method of present invention, the reduction of CaO by the metallic reducing agent allows the Ca alloy phase and flux phase to be very uniformly mixed with one another, with the result that the vaporization loss of metallic Ca can be suppressed to a high extent.
A process for the production of steel with increased ductility in which a sulfur-containing steel melt is deoxidized and, if desired, is supplied with alloying elements, the deoxidized melt being treated with magnesium or with both magnesium and calcium as part of a purification action simultaneously reducing the sulfur content, and the reaction is carried out in a casting ladle having a lining free from siliceous oxides. The melt is covered with a synthetic slag free from siliceous oxides and the magnesium-containing substance is introduced in fine-grain particulate form into the melt in a carrier gas at a level at least 2000 mm below the melt surfade and at a rate which is less than the maximum rate at which the magnesium-containing substance is capable of reacting with the melt.
A method for deoxidizing steel to effect exceptional cleanliness wherein a relatively high amount of aluminum is added to the tap ladle before the first one-third volume of steel is tapped, and then adding conventional deoxidizers while the final two-thirds volume of steel is tapped. Argon is subsequently blown through the steel at a rate not exceeding 10 scfm for a period of about nine to twenty minutes.
Production of resulphurized steel with enhanced machinability having a sulphur content of between 0.05 and 0.20% by weight, in which an alkali earth metal having a high affinity for sulphur (eg. Calcium or Calcium bearing alloys) are added to a steel melt in sufficient quantity to provide in the steel when solidified, isolated globular sulphide inclusions. Calcium additions of between 0.02 and 0.20% by weight are proposed.
