A slag conditioning agent for steel desulfurization is shown which is made by a process in which a dried slag material obtained from a secondary steelmaking process is mixed with quicklime particles. The quicklime particles react with moisture in the slag material to dry the slag material and produce a blend of slag material, hydrated lime and any unreacted quicklime. The blend is then sieved to separate out the hydrated lime. The retained dried fraction after sieving is then mixed with an Al.sub.2O.sub.3 mass fraction from which the slag conditioning agent can be collected. The slag conditioning agent has an equivalent mass ratio which is between 0.55 and 1.5.

The embodiments of the present disclosure provide a method for processing entrained slag inclusions in steel with deoxidized calcium with fixed aluminum. The method proposes a kinetic model and further proposes a criterion for determining which composition of inclusions are the entrained slag inclusions based on the process of compositional transformation of the entrained slag inclusions. The method can clarify whether the inclusions in the steel are entrained slag or not, identify the source of the inclusions, and further provide a clear direction for the control of such inclusions in industrial production. Corresponding industrial measures can then be implemented to adjust steelmaking processes, control the occurrence of entrained slag inclusions, reduce the count of entrained slag inclusions in steel, and enhance process efficiency and steel product quality.

A hot-rolled, low-temperature-resistant, H-shaped steel with a grade of 420 MPa includes the following chemical components in percentages by weight: C: 0.08-0.10%, Si0.2%, Mn: 1.25-1.45%, V: 0.03-0.045%, Ti: 0.015-0.025%, Cr: 0.15-0.30%, Al: 0.02-0.04%, N: 0.007-0.01%, P0.008%, S0.005%, O0.004%, and the balance being Fe and inevitable impurities. Its manufacturing adopts the characteristic of the flange of the small-specification H-shaped steel being thin in rectangular blank rolling, uses the design of a low C content suitable for normalizing rolling combined with a V micro-alloyed component, and adds an appropriate amount of Cr to control the cooling rate. The method avoids abnormal structures such as widmanstatten, which would reduce steel's low-temperature impact toughness, and results in a stably controlled, high-strength and high-toughness, hot-rolled, H-shaped steel with a grade of 420 MPa or more obtained on a hot-rolled H-shaped steel rolling mill.

A method for manufacturing pig iron in an electrical smelting furnace including a vessel, the method including the following successive steps: loading DRI product in the vessel, melting the DRI product to form a pig iron layer topped by a slag layer, and injecting a desulphurizing reagent directly in the pig iron layer. It also deals with the manufacturing of steel from the pig iron and the associated electrical smelting furnace.

A method for manufacturing pig iron in an electrical smelting furnace including a vessel, the method including the following successive steps: loading DRI product in the vessel, melting the DRI product to form a pig iron layer topped by a slag layer and, tapping the pig iron into a ladle, and adding a carbon containing material directly in the pig iron in the runner of at least one of the smelting furnace tap holes. It also deals with the manufacturing of steel from the pig iron and the associated electrical smelting furnace.