A method for operating a shaft furnace, in particular a blast furnace, is disclosed wherein at least one gas is introduced into the furnace. To achieve an acceleration of the reaction processes in the furnace, shockwaves are introduced into the furnace.

A method for manufacturing a low-carbon nitrogen-containing austenitic stainless steel bar sequentially includes smelting, electroslag remelting, and forging. During electroslag remelting, the steel ingot obtained in the smelting process is used as an electrode bar of the electroslag furnace and is remelted with specific slag and crystallized. The specific slag comprises CaF.sub.2 (65-70%), Al.sub.2O.sub.3 (15-20%), CaO (5-10%) and MgO (2-5%) in percentage by weight. Specific forging methods, including upsetting-and-drawing and radial forging, are used. In upsetting-and-drawing, the pass deformation is less than 35%, the pass reduction is 50-80 mm, the pass heating temperature is 1130-1150? C., and the pass deformation method is ellipse-ellipse-circle. The method can obtain the low-carbon high-strength nitrogen-containing austenitic stainless steel with uniformly distributed chemical composition, high purity and high strength.

A method of manufacturing a steel product into at least two different steelmaking units wherein an expected level of CO2 emissions for the manufacturing of said product in each respective steelmaking unit is calculated.

A method to manufacture a steel product in a steelmaking plant including several different tools, the method including the definition of at least two manufacturing routes using different tools and the calculation of the expected level of CO2 emissions associated to each of this defined manufacturing routes.

A method to manufacture a global tonnage of steel products in at least two steelmaking units wherein expected level emissions are calculated and compared with pre-defined targets.

To produce manganese containing ferroalloy for steel production, an agglomeration mixture is produced which comprises chromite ore concentrate and manganese ore fines with a grain size smaller than 6-9 mm. The mixture is agglomerated to produce green agglomeration products, such as pellets or other types of agglomerates. The green agglomeration products are sintered in a steel belt sintering furnace to produce either sinter or sintered pellets. The sinter or sintered pellets are smelted in a submerged arc furnace to produce manganese and chromium containing ferroalloy. The ferroalloy produced by the method comprises 6.0-35 w-% manganese and 31-54 w-% chromium.

Some variations provide a carbon-negative carbon product that is characterized by a carbon intensity less than 0 kg CO.sub.2e per metric ton of the carbon-negative carbon product, wherein the carbon-negative carbon product contains at least about 50 wt % carbon. In some embodiments, the carbon intensity is less than ?500 kg CO.sub.2e per metric ton of the carbon-negative carbon product. Other variations provide a carbon-negative metal product (e.g., a steel product) that is characterized by a carbon intensity less than 0 kg CO.sub.2e per metric ton of the carbon-negative metal product, wherein the metal product contains from 50 wt % to 100 wt % of one or more metals and optionally one or more alloying elements. In some embodiments, the carbon-negative metal product is characterized by a carbon intensity less than ?200 kg CO.sub.2e per metric ton of the carbon-negative metal product. The carbon-negative metal product can contain a wide variety of metals.

Martensitic stainless steel, characterized in that its composition consists of, in percentages by weight: 0.10%C0.45%; tracesMn1.0%; tracesSi1.0%; tracesS0.01%; tracesP0.04%; 15.0%Cr18.%; tracesNi0.50%; tracesMo0.50%; tracesCu0.50%; tracesV0.50%; tracesNb0.03%; tracesTi0.03%; tracesZr0.03%; tracesAl0.010%; tracesO0.0080%; tracesPb0.02%; tracesBi0.02%; tracesSn0.02%; 0.10%N0.20%; C+N0.25%; Cr+16N5C16.0%; preferably 17Cr+500C+500N570%;

the rest being iron and impurities resulting from the development.

A method for the production of a semi-finished product from this martensitic stainless steel, and cutting tool produced from this semi-finished product.

A corrosion resistant alloy suitable for use as a seamless tubular is described. The corrosion resistant alloy includes 13-15 wt. % chromium, 5-7 wt. % nickel, and 2.5-4.5 wt. % molybdenum. The balance of the corrosion resistant alloy is iron.

A charged material containing a metal raw material of at least one of ferrochromium containing metal Si or ferrosilicon and unreduced slag containing Cr oxide generated by oxidation refining is charged into an AC electric furnace including three electrodes, a mass ratio of a metal Si amount to a Cr oxide amount being from 0.30 to 0.40, and a C concentration being from 2.0% by mass to a saturation concentration.