The present invention relates to a steel rebar comprising the following ingredients: 0.005%-0.030% of C, 0.3%-0.6% of Si, 1.2%-2.5% of Mn, 0.01% or less of P, 0.01% or less of S, 8.0%-10.0% of Cr, 1.0%-3.0% of Mo, 0.2%-0.4% of Sn, 0.01%-0.05% of Rare Earth element, and the remainder being Fe and unavoidable impurities. The present invention also provides a production method of steel rebar. The steel rebar of the present invention has excellent comprehensive mechanical properties and corrosion resistance performance, while meeting the requirements of anti-knock, the service life in sea water of the steel rebar is increased, thus it can be widely used in reinforced concrete structures in ocean environment.

The present invention relates to a steel rebar comprising the following ingredients: 0.005%-0.030% of C, 0.3%-0.6% of Si, 1.2%-2.5% of Mn, 0.01% or less of P, 0.01% or less of S, 8.0%-10.0% of Cr, 1.0%-3.0% of Mo, 0.2%-0.4% of Sn, 0.01%-0.05% of Rare Earth element, and the remainder being Fe and unavoidable impurities. The present invention also provides a production method of steel rebar. The steel rebar of the present invention has excellent comprehensive mechanical properties and corrosion resistance performance, while meeting the requirements of anti-knock, the service life in sea water of the steel rebar is increased, thus it can be widely used in reinforced concrete structures in ocean environment.

The present invention provides an ultrahigh hole expansion steel and a method for manufacturing therefor. The steel comprises the following components in percentage by mass: C: 0.03-0.09%; Si0.2%; Mn: 0.5-2.0%; P0.02%; S0.003%; Al: 0.2-1.2%; N0.004%; Ti: 0.05-0.20%; Mo: 0.05-0.5%; Mg0.005%; O0.003%; B0.001%; and the balance being Fe and inevitable impurities. wherein C, Mn, Mo and B in the steel satisfy the following formula: 0.252C+Mn/3+Mo+150B1.5; wherein each chemical element in the formula represent the numerical value before the percentage sign of the percentage by mass of corresponding chemical elements. The steel according to the present invention has excellent matching of strength, plasticity and hole expansion performance, and can be applied in passenger vehicle chassis parts that require high strength and thickness reduction, such as a control arm and a subframe.

The present invention provides an ultrahigh hole expansion steel and a method for manufacturing therefor. The steel comprises the following components in percentage by mass: C: 0.03-0.09%; Si0.2%; Mn: 0.5-2.0%; P0.02%; S0.003%; Al: 0.2-1.2%; N0.004%; Ti: 0.05-0.20%; Mo: 0.05-0.5%; Mg0.005%; O0.003%; B0.001%; and the balance being Fe and inevitable impurities. wherein C, Mn, Mo and B in the steel satisfy the following formula: 0.252C+Mn/3+Mo+150B1.5; wherein each chemical element in the formula represent the numerical value before the percentage sign of the percentage by mass of corresponding chemical elements. The steel according to the present invention has excellent matching of strength, plasticity and hole expansion performance, and can be applied in passenger vehicle chassis parts that require high strength and thickness reduction, such as a control arm and a subframe.

A method of manufacturing molten pig iron into an electrical smelting unit. The method comprises the following successive steps: providing a directly reduced iron product feeding the DRI product into the smelting unit feeding together with the DRI product, ferrous scrap having a size lower than 80 mm, melting the DRI product and the ferrous scrap to produce molten pig iron. A method to produce liquid steel from manufactured pig iron is also provided.

A method of manufacturing molten pig iron into an electrical smelting unit. The method comprises the following successive steps: providing a directly reduced iron product feeding the DRI product into the smelting unit feeding together with the DRI product, ferrous scrap having a size lower than 80 mm, melting the DRI product and the ferrous scrap to produce molten pig iron. A method to produce liquid steel from manufactured pig iron is also provided.

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 silicon 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 an 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 silicon 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 an associated electrical smelting furnace.

A method for manufacturing pig iron in an electrical smelting furnace including a vessel 20, 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 20, 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.