51results about How to "Improved stability against tempering" patented technology

The invention belongs to the field of tool and die, specifically to a low-cost hot die steel. The chemical compositions of the steel (weigh%) are: C: 0.38-0.42%, Si: 0.9-1.1%, S<=0.030%, P<=0.030%, Mn: 0.3-0.5%, W: 0.9-1.2%, Mo: 0.45-0.55%, Cr: 4.8-5.2%, V: 0.25-0.45%, Nb: 0.08-0.15% and Fe and unavoidable impurities: the blance. The steel of the invention can be used as a substitute for high-alloy-containing H13, has similar comprehensive performance to H13, superior temper resistance and low chromium; the rational alloy ratio saves cost more than 20%, compared with H13 steel, thus having better economical benefit.

The invention discloses a preparation method of a hot-rolled steel coil rod for a 10.9-level high-strength bolt. The preparation method comprises the following steps of A, pretreatment and desulfurization of molten iron; B, smelting of molten steel; C, deoxygenation alloying; D, LF furnace refining of the molten steel; E, casting of the molten steel; F, billet heating; and G, controlled rolling and controlled cooling. According to the preparation method of the hot-rolled steel coil rod for the 10.9-level high-strength bolt, the prepared hot-rolled steel coil rod is high in cleanliness and good in hardenability and has proper strength and hardness as well as excellent plastic toughness and cold heading machining deformation capacity, the 10.9-level high-strength bolt can be produced through cold heading machining directly without spheroidizing annealing, manufacturing procedures and energy consumption are reduced, and production cost is reduced.

The invention relates to medium-carbon alloy cast steel shots and a manufacturing method thereof, which is characterized in that, each medium-carbon alloy cast steel shot comprises the following chemical components in percentage by mass: 0.35 percent of carbon, 0.11 percent of silicon, 0.45 percent of manganese, 1.2 percent of chrome, 0.015 percent of sulfur, 0.020 percent of phosphor and the balance of iron and inevitable impurities. The manufacturing process comprises the following steps of: mixing and smelting, namely, smelting the raw material composition mixed proportionally into liquid steel, pouring the liquid steel into a tundish and performing deoxygenation by adopting an deoxidant; preparing shots by a centrifugally forming method, namely, pouring deoxygenized liquid steel into a centrifugal disc which rotates at a high speed, throwing out the liquid steel under the action of a centrifugal force to make the liquid steel fall into a cooling water pool, and taking the liquid steel out and drying the cooled steel to obtain formed cast steel shots; and performing heat treatment, namely, heating the formed cast steel shots until the temperature reaches 860 to 880 DEG C, performing cold quenching after keeping the temperature for 20 to 40 minutes, tempering for 40 to 80 minutes at the temperature of between 350 and 500 DEG C, and after tempering, cooling rapidly by a steel plate vibrating screen water cooling method to produce the medium-carbon alloy cast steel shots. The medium-carbon alloy cast steel shots and the manufacturing method thereof have the advantages of guaranteeing the high rigidity of the steel shots, avoiding crack generated in the centrifugally forming process and the heating tempering process, improving the toughness and the like.

The invention belongs to the field of tool and die, specifically to a low-chromium low-cost hot die steel. The chemical compositions of the steel (weigh%) are: C: 0.38-0.42%, Si: 0.9-1.1%, S<=0.030%, P<=0.030%, Mn: 0.3-0.5%, W: 0.9-1.2%, Mo: 0.45-0.55%, Cr: 2.8-3.2%, V: 0.25-0.45%, Nb: 0.08-0.15% and Fe and unavoidable impurities: the balance. The steel of the invention can be used as a substitute for high-alloy-containing H13, has similar comprehensive performance to H13, superior temper resistance, low cost and low chromium; the rational alloy ratio saves cost more than 20%, compared with H13 steel, thus having better economical benefit.

The present invention discloses a series flux-cored wire for reparation and refabrication of large-size medium-high carbon steel components and parts. Its chemical composition includes (wt%) 5-10 of fluorite, 25-45% of high-carbon ferrochrome, 2-10% of high-carbon manganese iron, 5-8% of tantiron, 10-15% of ferro-molybdenum, 8-14% of rare earth oxide, 5-15% of metal nickel, 2-5% of ferrovanadium,0.5-2% of graphite, 2-4% of chloride and 1-2.5% of aluminium-magnesium alloy. Its external covering adopts low-carbon steel tape.