30results about How to "Increased ferrite content" patented technology

The invention discloses a melting process for producing synthetic cast iron by utilizing SiC carburizing siliconizing, which produces the synthetic cast iron by taking scrap steel, pig iron and cast iron returns or scrap steel and cast iron returns as the main raw materials in an induction furnace by utilizing SiC as an carburizing siliconizing agent, wherein the addition of SiC is 0.5-3%, and the granularity is 6-20mm; SiC is added to a hearth before melting or is added during the melting process, or the two modes cooperate to be used. The invention utilizes SiC to replace the pig iron and silicon iron carburizing siliconizing to reduce the pig iron and silicon iron so as to reduce the cost, and meanwhile, the tendency of the molten iron chill and the reverse chill of the produced synthetic cast iron is small; the dimensions of graphite pebbles in produced nodular cast iron are small, the sphericity or roundness is high, the content of ferrite is high, and the roughness of the nodular cast iron is improved; the organization of produced grey cast iron is refined, and the mechanical property and the abrasion resistance are obviously improved. The invention can be used for producingvarious trademarks of grey cast iron, nodular cast iron and alloy cast iron.

The invention discloses a machining tool for a spherical plate. The tool comprises an upper mold and a lower mold, wherein the lower mold comprises a lower columnar structure defined through welding connection of sides of at least three lower rib plates and a seat plate arranged at the bottom of the lower columnar structure; a machining concave end surface is arranged at the top of the lower columnar structure, and the curve of the machining concave end surface is consistent with the radian of a curved surface of the to-be-machined spherical plate; the upper mold comprises an upper columnar structure defined through welding connection of sides of at least three upper rib plates and a top plate arranged at the top of the upper columnar structure; and a machining convex end surface is arranged at the lower end of the upper columnar structure and is matched with the machining concave end surface in radian. The smooth degree of the appearance of the plate can be guaranteed with the tool, assembly, electric welding and polishing in following processes can be reduced, the manufacturing period of the spherical plate can be shortened, and the manufacturing cost of the spherical plate can be saved.

The application provides a non-quenched and tempered steel for a crankshaft, a crankshaft forging and a preparation process thereof, which belong to the technical field of non-quenched and tempered steel. Non-quenched and tempered steel by weight percentage: C 0.36‑0.39%, Si 0.50‑0.65%, Mn 1.35‑1.50%, P 0‑0.030%, S 0.040‑0.055%, Cr 0‑0.25%, Mo 0‑0.20 %, Al 0‑0.03%, N 0.010‑0.020%, carbon equivalent Ceq=0.75‑0.81%. The hardenability of non-quenched and tempered steel is: J5mm 47‑52HRC, J9mm 35‑42HRC, J13mm 30‑36HRC; tensile strength ≥ 760MPa; elongation A ≥ 14%; band structure ≤ 2.0; Brinell hardness is 220‑250HBW, suitable for making crankshaft forgings.

The invention discloses a method for controlling the phase proportion of a two-phase corrosion-resistant layer on the surface of carbon steel. Austenitic deposited metal is used as a transitional isolation layer; high-current and high-efficiency arc surfacing welding is performed with high-chromium and high-nickel stainless steel electrodes to form a filling layer, that is, corrosion-resistant surfacing welding of superalloyed austenite-ferrite dual-phase structure During the surfacing process, the interlayer temperature is controlled below 120°C; the cover surface is surfacing with low-current argon tungsten arc welding to form a cover layer; after the surfacing welding is completed, post-weld heat treatment is not required; 24 hours after welding Conduct penetrant flaw detection, and use a ferrite tester to measure the ferrite content. The welding method provided by the invention can form an approximately equal-proportion dual-phase corrosion-resistant surfacing layer, and does not require heat treatment after welding, which can simplify the processing technology and reduce the manufacturing cost.

The invention discloses a waste-steel-smelting-ductile-iron process with the carburant absorptivity reaching 95% or above. In a smelting furnace, furnace burdens and carburant are added at many times, and the furnace burdens comprise ductile iron chippings, foundry returns and waste steel; after the furnace burdens in the smelting furnace completely fuse, temperature rise is started, after all carburant fuses completely, a slag remover is added, and slag is picked out of the furnace with a rolling rod; after stokehole samples are tested to be qualified, spheroidizing is started, and then secondary inoculation is carried out; casting is carried out; the nodulizing stage of obtained ductile iron is 2 stage to 3 stage, and the hardness ranges from 155 HB to 165 HB; and based on the mass percent of the ductile iron, the pearlite content is 5%+ / -0.5%, the S content is smaller than 0.02%, the ferrite content is larger than 85%, and free cementite is not contained. According to the process, through creative detail treatment and furnace burden mastering in the production process, the carburant absorptivity is remarkably improved, the product quality is improved, and the production cost is reduced.

The invention relates to the technical field of manufacturing of wind-power generating equipment, in particular to a wind-power equipment casting and a manufacturing method thereof. The wind-power generating casting comprises the following chemical components in percentage by mass: 3.60-3.80 percent of C, 2.2-2.4 percent of Si, less than 0.25 percent of Mn, 0.006-0.015 percent of K, 0.006-0.015 percent of Na, 0.008-0.015 percent of Bi, 0.015-0.028 percent of Sb, 0.002-0.004 percent of Sr, 0.035-0.055 percent of Ba, 0.035-0.055 percent of Ca, 0.030-0.050 percent of Al, 0.032-0.055 percent of Mg, less than 0.03 percent of P, less than 0.01 percent of S and the balance of Fe. In the method, an electric furnace is adopted for smelting, and low-manganese waste steel and graphite are added instead of cast iron, supplementary iron and carbon for serving as major raw materials; for further improving the performance of the wind-power casting, a small quantity of micro-alloy elements such as bismuth, antimony, potassium, sodium, strontium, calcium, barium, aluminum and the like are added, so that the graphite is refined, the spheroidizing effect of the graphite is improved, and the effect of preventing degraded spheroidization is achieved; spheroidizing treatment with pure magnesium is performed; and inoculation treatment is performed by using a ferrite spheroidal graphite cast iron inoculant before casting. The wind-power equipment casting has the advantages of simple and convenient production process, low cost, high intensity and high toughness at room temperature and low temperature.

The invention relates to the field of spheroidal graphite cast iron, in particular to ferritic spheroidal graphite cast iron and a preparation method thereof. The ferritic spheroidal graphite cast iron comprises, by mass, 3.5%-3.8% of carbon, 2.4%-2.7% of silicon, 0.29%-0.35% of manganese, 0.03%-0.04% of cerium, 0.045%-0.06% of magnesium, 0.08%-0.1% of yttrium, 0.01%-0.02% of molybdenum, 0.02%-0.03% of rhenium, not more than 0.04% of phosphorus, not more than 0.018% of sulphur and the balance iron. The preparation method particularly includes the steps of (1), melting raw materials by a medium-frequency induction furnace prior to desulfurization; (2), uniformly mixing silicon carbide powder with rare earth magnesium alloy, then pouring the mixture into a spheroidizing package, covering the spheroidizing package with a first inoculant for spheroidizing and primary inoculation treatment prior to secondary inoculation treatment, and casting so as to obtain a cast; (3), subjecting the cast to heat treatment so as to obtain the ferritic spheroidal graphite cast iron. The ferritic spheroidal graphite cast iron is high in spheroidizing ratio and strength and excellent in toughness and impact plasticity, and the preparation method is simple and efficient.

The invention relates to a smelting method, particularly a smelting method for acquiring qualified mechanical properties under low-temperature nickel-free conditions, which is characterized by comprising the following steps: melting, embedding a nodulizer and an inoculator, tapping, and casting a test block. The method provided by the invention is unique, can acquire higher tensile strength and elongation percentage, enables the matrix structure of the test block to contain less pearlite, enhances the nodularity of the test block, and ensures the quality and low-temperature impact value of the casting on the premise of reasonably selecting chemical composition.

The invention discloses a production method for reducing the hardness of X80M-grade pipeline steel. Through a high-temperature rolling process, reasonable adjusting of phosphorus removal process and perfecting of rolling schedule, a laminar flow cooling process is optimized, a hybrid tissue structure is obtained, wherein the edge of the hybrid tissue structure is mainly made of quasi-polygonal ferrite, and the core of the hybrid tissue structure is mainly made of acicular ferrite, bainite and a small amount of martensite and austenite islands, it is ensured that the Wechsler hardness value ofthe surface and the section of a steel plate is stabilized within 220, the performance requirements for the steel plate are ensured, and economic benefits are remarkable.

The invention provides a stainless steel flux-cored welding wire, which includes a stainless steel strip and a flux core, the flux core is filled in the stainless steel strip, and the flux core includes the following components and the mass percentage of each component is: 0.7~ 1.4% fluoride, 0.8-1.5% potassium sodium arc stabilizer, 0.3-0.8% graphene, 2-3% manganese-silicon alloy, 5-10% chromium powder, 2-5% ferrosilicon, 9-14% of ferrotitanium and the rest are iron powder. The stainless steel flux-cored welding wire has a soft and stable arc during welding. After welding, the weld seam has a beautiful shape, less spatter, and no small pores in the weld seam. At the same time, the weld metal has excellent wear resistance, corrosion resistance, and high temperature resistance.