33results about How to "Excellent ultra-low temperature toughness" patented technology

The invention discloses a steel used at a lower temperature and a method for manufacturing the same. The steel comprises the following chemical components by weight percentage: 0.060 to 0.090 percent of C, less than or equal to 0.20 percent of Si, 1.10 to 1.50 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.003 percent of S, 0.040 to 0.070 percent of Als, 0.05 to 0.45 percent of Cu, 0.05 to 0.35 percent of Ni, 0.05 to 0.30 percent of Cr, 0.007 to 0.011 percent of Ti, 0.007 to 0.020 percent of Nb, less than or equal to 0.0040 percent of N, 0.001 to 0.011 percent of Ca, and the balance of Fe and inevitable impurities. The manufacturing process comprises of the steps: making the steel plate obtain excellent low-temperature toughness and making the steel plate bear the big line energy welding. The steel and the method can be widely applied to petroleum natural gas pipelines, low-temperature gas tank bodies LPG, low temperature steel plates of LNG.

The invention provides an HT550 steel plate with ultrahigh toughness and excellent weldability and a manufacturing method thereof. Based on a component system which is subjected to ultralow C-high Mn-Nb microalloying-ultramicro Ti treatment, Mn/C is controlled in the range from 15 to 30, (%Si)*(%Ceq) is less than or equal to 0.050, (%C)*(%Si) is less than or equal to 0.010, (%Mo)*[(%C)+0.13(%Si)] is in the range from 0.003 to 0.020, Ti/N is in the range from 2.0 to 4.0, (Cu+Ni+Mo) is alloyed, Ni/Cu is greater than or equal to 1.0, Ca treatment is performed, and the ratio of Ca/S is within the range from 0.80 to 3.00; TMCP (Thermo-Mechanical Control Process) is optimized, so that the microscopic structure of the steel plate comprises fine ferrites and self-tempered bainite; and the steel plate has an average grain size below 15 microns, yield strength greater than or equal to 460 MPa, tensile strength in the range from 550 MPa to 700 MPa, a yield ratio less than or equal to 0.85, and -60 DEG C Charpy ballistic work (single value) greater than or equal to 60 J; therefore, the steel plate is capable of bearing large thermal input welding while having even and excellent match of strong obdurability and strong plasticity; and as a result, the steel plate is especially suitable for a sea bridge structure, an ocean wind tower structure, an ocean platform structure and a hydroelectric structure.

The invention discloses a full-automatic submerged-arc welding solid-core welding wire for high-manganese steel for preparing an LNG storage tank. According to the technical scheme, the full-automatic submerged-arc welding solid-core welding wire comprises 0.25-0.45wt% of C, 23-26wt% of Mn, 6-8wt% of Ni, 3-5wt% of W, 0.02-0.04wt% of N, less than or equal to 0.02wt% of P, less than or equal to 0.001wt% of S and the balance of Fe and inevitable impurities. The full-automatic submerged-arc welding solid-core welding wire has the advantages that the price of adopted alloy elements is low, and an alloy component system is simple; and the low-temperature toughness of weld metal formed by the prepared full-automatic submerged-arc welding solid-core welding wire is excellent, the strength of the full-automatic submerged-arc welding solid-core welding wire is matched with the strength of the ultralow-temperature high-manganese steel for preparing the LNG storage tank, and the technical requirements for the strength and the ultralow-temperature toughness of the welded LNG storage tank can be met.

The invention discloses a high-efficiency submerged arc welding metal powder-cored flux-cored wire used for ultra-low-temperature high-manganese steel, the high-efficiency submerged arc welding metalpowder-cored flux-cored wire is composed of a steel strip and a metal powder core, the chemical composition of the steel strip is as follows: C is 0.20-0.23 wt%, Si is 0.03-0.05 wt%, Mn is 6-8 wt%, P<=0.002 wt%, S <=0.001 wt%, the balance is Fe and unavoidable impurities. The chemical composition of the metal powder core is as follows: 18-20wt% of electrolytic manganese, 3-4wt% of manganese-silicon alloy, 8-10wt% of nickel powder, 6-8wt% of low-carbon ferrochromium, 4-6wt% of tungsten powder, 2.0-3.0 wt% of potash feldspar, and the balance of iron powder, and the total component content is 100%. The invention can meet the technical requirements for the strength and ultra-low temperature toughness of the welded LNG storage tank.

The invention discloses an ultra-thick, ultra-high-toughness and excellent-weldability 1000 MPa-grade steel plate and a manufacturing method thereof. A component system of ultra-low C-ultra-low Si-medium Mn-(Ti+Nb+V+B) microalloyed steel is adopted as the basis, the content of acid-soluble Als in the steel is properly increased, metallurgical methods that Als/[(%N)-0.292(%Ti)] is larger than or equal to 23, (%C)*(%Si) is smaller than or equal to 0.016, Ca treatment is performed, a Ca/S ratio is 1.00-3.00, and (%Ca)*(%S)0.18 is smaller than or equal to 2.5*10<-3> are adopted, TMCP plus off-linequenching and tempering process (QT) is optimized, [H*(t<relaxation>)*xi]/[(T<finish rolling>-T <cooling stopping>)*(Ceq*V<cooling rate>)] is controlled to be larger than or equal to 40 and smaller than or equal to 550, (T<quenching>)*[lg(t<quenching maintenance>)]/[(%Mo)+0.73(%Cr)+1.67(%V)+311(%B)] is controlled to be larger than or equal to 730 and smaller than or equal to 1050, and [(T<tempering>)*[lg(t<tempering maintenance>)]/DI is controlled to be larger than or equal to 320 or smaller than or equal to 120, the microstructure of the finished steel plate is fine low carbon tempered martensite plus little tempered lower bainite, the average crystal size is less than 20[mu]m, and the excellent plasticity and toughness HT950 steel plate is obtained.

The invention discloses an ultralow-temperature excellent-tenacity high-manganese medium-thick plate and a preparation method of the medium-thick plate, and belongs to the technical field of steel materials. The medium-thick plate is prepared from, by weight, 0.31-0.67% of C, 0.02-0.48% of Si, 22.0-27.3% of Mn, 0.08% or less of P, 0.06% of less of S, 1.5-4.64% of Al and the balance Fe and inevitable impurities. The preparation method comprises the steps that 1, a steel blank is heated and kept warm; 2, the heated steel blank is rolled in the first stage to form a hot-rolled steel material; and3, the hot-rolled steel material is cooled, and the -196 DEG C excellent-tenacity high-manganese medium-thick plate is obtained. The high-manganese medium-thick plate can be used after being rolled and has excellent ultralow-temperature tenacity and high strength, alloy elements do not need to be added, and the cost is far lower compared with 9Ni steel.

Provided are an austenitic steel having excellent machinability and ultra-low temperature toughness in a weld heat-affected zone including 15 wt % to 35 wt % of manganese (Mn), carbon (C) satisfying 23.6C+Mn≧28 and 33.5C−Mn≦23, 5 wt % or less (excluding 0 wt %) of copper (Cu), chromium (Cr) satisfying 28.5C+4.4Cr≦57 (excluding 0 wt %), and iron (Fe) as well as other unavoidable impurities as a remainder, wherein a Charpy impact value of a weld heat-affected zone at −196° C. is 41 J or more, and a method of manufacturing the steel.

According to the present invention, a low-cost ultra-low temperature steel may be obtained, a stable austenite phase may be formed at low temperature, carbide formation may be effectively suppressed, and a structural steel having excellent machinability and ultra-low temperature toughness in a weld heat-affected zone may be provided.

The invention relates to a manual electric arc welding welding rod used for ultralow-temperature high manganese steel. According to the technical scheme, the manual electric arc welding welding rod is composed of a welding rod core and a coating; the welding rod core comprises the following chemical components of 0.75-0.95 wt% of C; 26-30 wt% of Mn; 4.5-6.5 wt% of Ni; 1.5-3.5 wt% of Cr; 3.5-5.5 wt% of Al; P less than or equal to 0.002 wt%; S less than or equal to 0.002 wt%; and the balance Fe and inevitable impurities, the coating comprises the following chemical components of 40-45 wt% of fluorite; 15-20 wt% of marble; 4-10 wt% of rutile; 3-6 wt% of zircon sand; 1-2 wt% of sodium carbonate; and the balance Fe powder; and a preparation method of the manual electric arc welding welding rod comprises the following steps of blending according to the chemical components of the coating, mixing, adding a binder, uniformly stirring, and pressing and coating on the surface of the welding rod core to prepare the manual electric arc welding welding rod used for the ultralow-temperature high manganese steel. The manual electric arc welding welding rod used for the ultralow-temperature high manganese steel is low in cost and simple in alloy system; and formed weld metal has the characteristics of ultralow temperature and high toughness, and the strength is matched with the strength of the ultralow-temperature high manganese steel.

The invention discloses a 700 MPa grade low temperature quenched and tempered steel plate with excellent weldability and fatigue resistance and a manufacturing method thereof. The steel plate comprises the following components in percentage by weight: 0.050-0.090% of C, less than or equal to 0.15% of Si, 1.30-1.60% of Mn, less than or equal to 0.013% of P, less than or equal to 0.0030% of S, 0.10-0.35% of Cu, 0.50-0.90% of Ni, 0.15-0.35% of Cr, 0.15-0.35% of Mo, 0.008-0.030% of Nb, 0.030-0.060% of V, 0.008-0.014% of Ti, 0.030-0.060% of Al, less than or equal to 0.0003% of B, less than or equalto 0.0050 % of N, 0.0010 -0.0040% of Ca, and the balance Fe and inevitable inclusions. A component system of ultra-low C-Mn-(Ti plus Nb plus V) microalloyed steel is adopted as a substrate, so that an excellent fit of strength, ultra-low temperature toughness and strength-toughness of the 700 MPa grade low temperature quenched and tempered steel plate is obtained, and the weldability and machinability of the steel plate are also excellent.

The invention relates to a manufacturing method of an X70M pipeline steel plate used under low-cost and ultralow-temperature conditions. The X70M pipeline steel plate used under the low-cost and ultralow-temperature conditions is manufactured through the process steps of KR molten iron pretreatment, BOF smelting, RH vacuum degassing, LF refining, RH vacuum degassing, continuous casting of a continuous casting billet with the thickness of 150mm, checking and cleaning of the continuous casting billet, hot charging and hot conveying at the temperature of 350-680 DEG C, casting billet heating, high-pressure water descaling, rolling, ACC cooling, straightening, steel plate shearing and inspection and warehousing in sequence. The pipeline steel plate produced by adopting a hot charging and hot conveying process, an ultralow C and microalloy composite adding process and a controlled rolling and controlled cooling process can meet the use requirements under the ultralow-temperature conditionsthat the Charpy impact work at -80 DEG C is greater than or equal to 120J and the drop hammer shearing area at -20 DEG C is greater than or equal to 85%.

The invention relates to a self-protection flux-cored wire suitable for ultralow-temperature high manganese steel. According to the technical scheme, the self-protection flux-cored wire is composed of a carbon steel strip, a single-strand alloy welding wire and flux-cored powder. The carbon steel strip comprises the following chemical components: 0.03-0.05 wt% of C, 0.05-0.08 wt% of Si, 0.5-0.8 wt% of Mn, less than or equal to 0.005 wt% of P, less than or equal to 0.005 wt% of S and the balance of Fe. The single-strand alloy welding wire comprises the following chemical components: 0.3-0.6 wt% of C, 0.05-0.2 wt% of Si, 24-33 wt% of Mn, less than or equal to 0.003 wt% of P, less than or equal to 0.003 wt% of S and 4-7 wt% of Ni. The flux core powder comprises the following chemical components in percentage by weight: 40 to 50 percent of barium fluoride, 10 to 17 percent of rutile, 4 to 7 percent of aluminum powder and 2 to 6 percent of sodium fluoroaluminate. Among the three chemical components, the balance is Fe and inevitable impurities. Weld metal formed by the self-protection flux-cored wire suitable for the ultralow-temperature high-manganese steel has the characteristic of high toughness under the ultralow-temperature service condition, and the strength of the weld metal is matched with that of the ultralow-temperature high-manganese steel.