2217 results about "Austenite" patented technology

An austenoferritic stainless steel with high tensile elongation includes iron and the following elements in the indicated weight amounts based on total weight: carbon<0.04% 0.4%<silicon<1.2% 2%<manganese<4% 0.1%<nickel<1% 18%<chromium<22% 0.05%<copper<4% sulfur<0.03% phosphorus<0.1% 0.1%<nitrogen<0.3% molybdenum<3% the steel having a two-phase structure of austenite and ferrite and comprising between 30% and 70% of austenite, wherein Creq=Cr %+Mo %+1.5 Si % Nieq=Ni %+0.33 Cu %+0.5 Mn %+30 C %+30 N % and Creq/Nieq is from 2.3 to 2.75, and wherein IM=551-805(C+N)%-8.52 Si %-8.57 Mn %-12.51 Cr %-36 Ni %-34.5 Cu %-14 Mo %, IM being from 40 to 115.

The present invention relates to a process for producing steel with retained austenite. In one embodiment, the process comprises the steps of heating a steel alloy to produce austenite, quenching the steel to produce martensite, and carbon partitioning to transfer carbon from the martensite to the austenite.

A process comprising the steps of providing a precursor for an implantable medical device, at least a portion of the precursor made of a shape memory material, the shape memory material having a receptacle for receiving a marker therein, the shape memory material having an austenitic and a martensitic phase; enlarging the receptacle while the shape memory material is in the martensitic phase; inserting a marker in the receptacle while the shape memory material is in the martensitic phase; and thereafter transforming the precursor to the austenitic phase.

An implantable expandable medical device in which selected regions of the device are in a martensite phase and selected regions are in an austenite phase. The martensitic regions exhibit pseudoplastic behavior in vivo and may be deformed without recovery under in vivo body conditions. In contrast the austenitic regions exhibit superelastic behavior in vivo and will recover their pre-programmed configuration upon deformation or release of an applied strain

The invention provides a super-strength steel plate comprising the following constituents (by weight percent): C 0.10-0.20%, Si<=0.6%, Mn 0.5-2.5%, Al <=0.03%, N 0.001-0.006%, B 0-0.0025%, Ca 0-0.006%, P<=0.015%, S<=0.005%, Ni 0.2-1.2%, Cr 0-0.8%, Cu 0-0.5% and Mo 0-0.6%, Ti 0.01-0.03%, V 0-0.1%, Nb 0.01-0.1%, balancing Fe and unavoidable foreign substance.

The invention discloses a low-alloy superhigh-intensity diphase steel and the heat treatment method, which is characterized in that: the components of the diphase steel (wt %) are C of 0.3 to 0.7, Si of 0.01 to 3.0, Al of 0.0 to 2.0, Nb of 0.0 to 0.25, V of 0.0 to 0.3, Mo of 0.0 to 2.0, Ni of 0.0 to 4.0, Mn of 0.05 to 3.0, Cr of 0.00 to 3.0, Co of 0.00 to 2.0, W of 0.0 to 2.0, S less than 0.04, P less than 0.04 and Fe of balance; the heat treatment method is that: a workpiece is first heated to 800 to 1000 degree centigrade to process the austenite treatment, and then the workpiece is quickly quenched into a liquid quenching medium of 50 to 250 degree centigrade, and then the workpiece is partitioned in a liquid quenching medium of 250 to 450 degree centigrade, and then the workpiece is quickly quenched into a liquid quenching medium of 100 to 250 degree centigrade for holding, finally the workpiece is quenched into water, and then the workpiece has a three-phase organization with martensite, nanometer ferrito martensite and remaining austenite with rich carbon. The low-alloy superhigh-intensity diphase steel and the heat treatment method has an advantage of increasing the intensity and plasticity of workpieces.

The invention relates to an austenitic stainless steel, a steel tube thereof and a manufacturing method thereof, wherein the austenitic stainless steel and the stainless steel tube comprise the components by mass percent: 0.060-0.14% of C, more than 0 and less than or equal to 0.50% of Si, more than 0 and less than or equal to 1.00% of Mn, less than 0.040% of P, less than 0.015% of S, 17.00-20.00% of Cr, 8.00-11.00% of Ni, 2.50-4.00% of Cu, 0.30-0.60% of Nb, 0.15-0.50% of Mo, 0.15-0.50% of Co, 0.05-0.14% of N, 0.001-0.01% of B, the rest of Fe and unavoidable impurity. The manufacturing method of the steel tube comprises: smelting and pouring to form steel ingots or continuously cast bloom, processing bar material, preparing tubular billet and further processing the steel tube; the method comprises the steps: the heating temperature of processing the bar material is 1250-1270 DEG C, heating temperature of preparing the tubular billet is 1100-1220 DEG C, and the finished product solid solution temperature is 1120-1190 DEG C. The austenitic stainless steel tube has high temperature creep strength and corrosion resisting performance at the high temperature.

The invention provides a super-strength steel plate comprising the following constituents (by weight percent): C 0.08-0.18%, Si<=0.6%, Mn 0.5-2.0%, Al <=0.018%, N<=0.008%, B<=0.0025%, Ca 0-0.006%, P<=0.015%, S<=0.005%, Ni <=1.0%, Cr<=0.8%, Cu<=0.5%, Mo<=0.6%, Ti 0.01-0.03%, V<=0.1%, Nb 0.01-0.1%, balancing Fe and unavoidable foreign substance. The invention also provides the preparing process.

The invention discloses a steel plate for stamping and quenching and a thermoforming method of the steel plate. The steel plate comprises the following chemical components in percentage by weight: 0.14-0.28% of C, less than 0.40% of Si, 0.4-2.0% of Mn, less than or equal to 0.010% of P, less than or equal to 0.004% of S, 0.016-0.040% of Al, 0.15-0.8% of Cr, 0.015-0.12% of Ti, 0.0001-0.005% of B, less than or equal to 0.005% of N, and the balance of Fe and inevitable impurities. The thermoforming method comprises the following steps: blanking by shearing the steel plate, and heating at Ac3 to (Ac3+80) DEG C to carry out austenization; after insulating for 5-10 minutes in the heating furnace, immediately transferring the steel plate to a metal mold the inside of which is cooled by introducing water, and stamping at the high temperature of 650-850 DEG C; cooling the formed workpiece in the closed mold, and cooling the mold by water circulation in the mold, wherein the cooling rate is greater than the critical cooling rate when austenite forms martensite, and the temperature of the workpiece leaving the hot stamping production line is below 150 DEG C; and carrying out air-cooling to room temperature. The steel plate has the advantages of simple component system and favorable hardenability; and the substrate tissues, which are ferrite and pearlite, are processed by hot stamping andquenching to obtain the all martensitic structure. The tensile strength of the steel plate can be higher than 1300 N/mm<2>.

A low Ni and high N austenitic-ferritic stainless steel is disclosed. It includes an austenitic-ferritic stainless steel having high formability and punch stretchability, crevice corrosion resistance, corrosion resistance at welded part, or excellent intergranular corrosion resistance, from a stainless steel structured by mainly austenite phase and ferrite phase, and consisting essentially of 0.2% or less C, 4% or less Si, 12% or less Mn, 0.1% or less P, 0.03% or less S, 15 to 35% Cr, 3% or less Ni, and 0.05 to 0.6% N, by mass, by adjusting the percentage of the austenite phase in a range from 10 to 85%, by volume. Furthermore, it includes an austenitic-ferritic stainless steel having higher formability by adjusting the amount of (C+N) in the austenite phase to a range from 0.16 to 2% by mass.

A sensor provides a persistent indication that it has been exposed to temperatures below a certain critical temperature for a predetermined time period. An element of the sensor made from shape memory alloy changes shape when exposed, even temporarily, to temperatures below the Austenitic start temperature A_s and well into Martensite finish temperature M_f off the shape memory alloy. The shape change of the SMA element causes the sensor to change between two readily distinguishable states. The sensor includes a one-way stop element that creates a persistent indication of the temperature history, allowing the sensor to be manufactured and stored at temperatures above the Austenitic temperature without causing the indication of an over-temperature event.

NDT inspection of an austenitic weld between two CRA Clad pipes using a phased ultrasonic transducer array system is described. The method may be performed during laying of gas/oil fatigue sensitive pipelines, for example, at sea. Two types of UT inspection may be generated simultaneously by a Phased Array on each side (Upstream and Downstream) of a girth weld. Firstly, mode converted longitudinal waves are used. These waves have properties that they propagate well. Shear waves are also used. The combination of these two ultrasonic waves, with the addition of surface waves, enables 100% of the girth weld to be inspected to the standard required in fatigue sensitive welds, such as Steel Catenary Risers. Shear waves and compression waves are emitted substantially contemporaneously. Defects may be detected and measured using time of flight information and amplitudes of radiation detected on reflection and on diffraction from the defect.

The invention provides a production method of an ultrahigh strength steel plate for cold forming and the steel plate. The method comprises the steps of smelting, casting, hot rolling, cold rolling, heating the cold-rolled steel plate through a continuous annealing production line with rapid cooling treatment to the austenite temperature, holding the temperature for a certain time, carrying out quenching treatment, obtaining a steel plate with the main structure of M+A and carrying out distribution treatment in a bell type annealing furnace. The steel plate comprises the following components in percentage by mass: 0.02-0.60% of C, 0.05-3.5% of Si, 0.20-3.50% of Mn, P more than or equal to 0.005 but less than or equal to 0.50%, S not more than 0.05%, 0.02-3.00% of Al, Cr not more than 0.50%, Ni not more than 3.00%, Cu not more than 0.50%, Mo not more than 1.50%, V not more than 0.50%, Ti not more than 0.20%, Nb not more than 0.20% and the balance of Fe and unavoidable impurities. The steel plate produced by adopting the method provided by the invention has the advantages of high strength and capability of cold forming and the process route of Q&P steel industrial production is effectively solved.

An austenitic stainless steel having excellent resistance to scale peeling which can suppress peeling of a protective oxide scale which is formed on the steel surface even when the steel undergoes repeated cycles of high temperature heating and cooling and which is suitable for use in a high temperature, humidified gas environment at a high temperature and particularly at 1023 K or above has a steel composition consisting essentially of C: 0.01-0.15%, Si: 0.01-3%, Mn: 0.01-2%, Cu: 0.1-2.5%, Cr: 23-30%, Ni: 16-25%, Al: 0.005-0.20%, N: 0.001-0.40%, P: at most 0.04%, S: at most 0.01%, at least one of Y and Ln series elements: a total of 0.005-0.1%, and a balance of Fe and unavoidable impurities, with the number of inclusions containing Y and Ln series elements in the steel surface being at most 5×10⁻³/μm².

This invention provides an oil-tempered wire having high strength (tensile strength of not less than 1960 MPa) and excellent workability and specifically provides a steel wire for high-strength springs comprising as steel components, in weight percent,the balance being Fe and unavoidable impurities, the steel wire having no nonmetallic inclusions of a size greater than 15 mum, a tensile strength of not less than 1960 MPa, and a yield ratio (sigma0.2/sigmaB) of not less than 0.8 and not greater than 0.9 or a yield ratio (sigma0.2/sigmaB) of not less than 0.8 and an amount of residual austenite of not greater than 6%. This invention also provides a method of producing the steel wire.

Alloy steels that combine high strength and toughness with high corrosion resistance are achieved by a dislocated lath microstructure, in which dislocated martensite laths that are substantially free of twinning alternate with thin films of retained austenite, with an absence of autotempered carbides, nitrides and carbonitrides in both the dislocated martensite laths and the retained austenite films. This microstructure is achieved by selecting an alloy composition whose martensite start temperature is 350° C. or greater, and by selecting a cooling regime from the austenite phase through the martensite transition region that avoids regions in which autotempering occurs.

Method for manufacturing a dental instrument having a desired machined configuration, without twisting the instrument. A blank of superelastic material is brought to an annealed state comprising a phase structure including a rhombohedral phase alone or in combination with austenite and/or martensite, or a combination of martensite and austenite. In this annealed state, a portion of the annealed material is removed at low temperature, for example less than about 100° C., and advantageously at ambient temperature, to form a final machined configuration for the instrument. The instrument is then heat treated and rapidly quenched to a superelastic condition.

A compact cooling system based on thermoelastic effect is provided. In one embodiment, the system comprises a pair of rollers serving as a heat sink, stress applicator and belt drive, a cold reservoir and a solid refrigerant belt coupled to the cold reservoir and to the heat sinks to pump heat from the cold reservoir to the heat sink. The refrigerant belt comprises solid thermoelastic materials capable of thermoelastic effect. The refrigerant material is mechanically compressed when entering the gap of the roller and subsequently released after passing through. When compressed the refrigerant material transforms to martensite phase and releases heat to the roller and neighboring materials. After released by the rollers, the refrigerant material transforms back to austenite and absorbs heat from the ambient atmosphere.

The present invention discloses one kind of thick steel plate with high strength and low welding crack sensitivity and its production process. The chemical composition includes C 0.06-0.09 wt%, Si 0.15-0.55 wt%, Mn 1.00-1.60 wt%, P not more than 0.015 wt%, S not more than 0.006 wt%, Ni 0.15-0.40 wt%, Cr not more than 0.30 wt%, Mo not more than 0.30 wt%, Cu not more than 0.30 wt%, V 0.02-0.06 wt%, Nb 0.005-0.05 wt% and Als 0.010-0.04 wt%, except Fe and inevitable impurities; and meets Pcm not higher than 0.20 % and Ceq not higher than 0.42 %. The production process includes two stage controlled rolling, on-line laminar flow cooling, off-line tempering and other steps. The produced steel plate has thickness up to 75mm, tensile strength not lower than 610 MPa and very low welding crack sensitivity.

The invention provides a high-strength hot-dip zinc plated steel sheet which exhibits high TS-El balance, excellent stretch frangeability, excellent workability due to low YR, and excellent impact characteristics, and a process for manufacturing the same. A high-strength hot-dip zinc plated steel sheet excellent in workability and impact characteristics, having a composition which contains by mass C: 0.05 to 0.3%, Si: 0.01 to 2.5%, Mn: 0.5 to 3.5%, P: 0.003 to 0.100%, S: 0.02% or below, Al: 0.010 to 1.5%, and N: 0.007% or below and further contains at least one element selected from among Ti, Nb and V in a total amount of 0.01 to 0.2% with the balance being Fe and unavoidable impurities and a microstructure which comprises, in terms of area fraction, 20 to 87% of ferrite, 3 to 10% (in total) of martensite and retained austenite, and 10 to 60% of tempered martensite and in which the average grain diameter of the second phase consisting of the martensite, retained austenite, and tempered martensite is 3[mu]m or below.

The invention relates to a super-thick steel plate for low yield ratio buildings with 460 MPa grade yield strength and a manufacturing method, which belongs to the technical field of high strength low alloy construction steel. The steel pipe comprises the following components by weight percent: 0.14 to 0.18 percent of C, 0.35 to 0.45 percent of Si, 1.40 to 1.50 percent of Mn, 0.025 to 0.035 percent of Nb, 0.040 to 0.050 percent of V, 0.010 to 0.020 percent of Ti, smaller than 0.020 percent of P, and the balance Fe. The rolling technology is as follows: the heating temperature is 1220 to 1250 DEG C, the tapping temperature is 1200 to 1230 DEG C, and two stages (ausrenitic recrystallization region and ausrenitic non-recrystailization region) are used for controlling rolling. The heat treatment technology is as follows: steel plates, the thickness of which is larger than or equal to 80 mm, are obtained after controlled rolling and cooling are carried out on continuously cast bloom, a two-phase region is heated up to 800 to 850 DEG C and insulated for 10 to 20 minutes, and then water quenching is adopted and the final cooling temperature is controlled to be less than or equal to 100 DEG C; 450 to 600 DEG C tempering treatment is carried out on the quenched steel plates, and finally the high strength low alloy construction steel plates are obtained. The steel plate not only has excellent comprehensive mechanical properties, but also lowers the cost and reduces the waste of resources.

The invention provides a super hard and tough, nano-crystal austenite steel bulk material having an improved corrosion resistance, and its preparation process. The austenite steel bulk material comprises an aggregate of austenite nano-crystal grains containing 0.1 to 2.0% (by mass) of a solid solution type nitrogen, wherein an oxide, nitride, carbide or the like of a metal or semimetal exists as a crystal grain growth inhibitor between and/or in said nano-crystal grains. For preparation, fine powders of austenite steel-forming components, i.e., iron and chromium, nickel, manganese, carbon or the like are mixed with a substance that becomes a nitrogen source. Mechanical alloying (MA) is applied to the mixture, thereby preparing nano-crystal austenite steel powders having a high nitrogen concentration. Finally, the austenite steel powders are consolidated by sintering by means of spark plasma sintering, rolling or the like.

An austenitic stainless steel hot-rolled steel material can be provided which has sea-water resistance and strength superior to conventional steel. Low-temperature toughness can be maintained, which is preferable in a structural member of speedy craft. The steel material can include an austenitic stainless steel hot-rolled steel material which excels in the properties of corrosion resistance, proof stress, and low-temperature toughness. In such austenitic stainless steel hot-rolling steel material, e.g., PI[=Cr+3.3(Mo+0.5W)+16N] ranges from 35 to 40, δ cal [=2.9 (Cr+0.3Si+Mo+0.5W)−2.6 (Ni+0.3Mn+0.25Cu+35C+20N)−18] ranges from −6 to +2, and a 0.2% proof stress at room temperature is not less than 550 MPa, Charpy impact value measured using a V-notch test piece at −40° C. is not less than 100 J/cm2, and the pitting potential measured in a deaerated aqueous solution of 10% NaCl at 50° C. (Vc′100) is not less than 500 mV (as it relates to saturated Ag/AgCl).

A gas turbine engine includes a variable area nozzle having a plurality of flaps. The flaps are actuated by a plurality of actuating mechanisms driven by shape memory alloy (SMA) actuators to vary fan exist nozzle area. The SMA actuator has a deformed shape in its martensitic state and a parent shape in its austenitic state. The SMA actuator is heated to transform from martensitic state to austenitic state generating a force output to actuate the flaps. The variable area nozzle also includes a plurality of return mechanisms deforming the SMA actuator when the SMA actuator is in its martensitic state.

The present invention discloses one kind of thick steel plate with great line energy and low welding crack sensitivity and its production process. The chemical composition includes C 0.06-0.10 wt%, Si 0.15-0.40 wt%, Mn 1.20-1.60 wt%, P not more than 0.015 wt%, S not more than 0.007 wt%, Ni 0.15-0.40 wt%, Cr not more than 0.30 wt%, Mo 0.15-0.30 wt%, V 0.02-0.06 wt%, Al 0.015-0.045 wt%, Ti 0.010-0.034 wt%, except Fe and inevitable impurities; and meets Pcm not higher than 0.20 %. The production process includes pre-treatment of molten iron, smelting in converter, LF furnace plus VD furnace vacuum treatment, two stage controlled rolling, on-line laminar flow cooling, tempering at 600-680 deg.c and other steps. The produced steel plate has no need of quenching and tempering treatment.

The invention relates to a welding process of ASTM A572 GR65 steel, which adopts mixed gas protection welding of argon and carbon dioxide for carrying out the backing welding and adopts the mixed gas protection welding of argon and carbon dioxide for filling and cover surface welding under the operating environment with temperature above 5 DEG C, and the operation is carried out according to the following steps: (1) the determination of parameters of the welding process; (2) the preparation before the welding: groove preparation and contra-aperture assembly; (3) the requirements of the assembly of the tack welding; (4) the backing welding by the mixed gas protection welding of argon and carbon dioxide; (5) the filling and the cover surface welding by the mixed gas protection welding of argon and carbon dioxide. The invention provides the welding process of the ASTM A572 GR65 steel which can prevent the welded steel pipes generating low-plastic quenched structure, prevent the overheating during the austenitic transformation, strengthen the austenitic stability and lower the welding deformation which is reduced by the welding stress.

The present invention has an object to reduce residual stress in a tensile direction of a weld on the inner side in contact with reactor water of austenitic stainless steel piping, and to change the residual stress into compressive stress, to reduce stress corrosive cracking. The present invention provides a welding process for stainless steel piping of laminating two types of welding wire made of different materials in a groove of austenitic stainless steel piping, including at least one of a first layer penetration welding step of performing a predetermined back bead width on the back side of the groove bottom and a tack welding step, a first lamination welding step of lamination welding of austenitic stainless steel wire from the bottom to the top of the groove, and a second lamination welding step of lamination welding of nickel-base alloy wire to a final layer at the top of the groove.

A high-strength hot-dip galvanized steel sheet is provided which has a TS of 590 MPa or higher and is excellent in ductility and stretch flangeability. Also provided is a process for producing the steel sheet. The steel sheet has a composition comprising, in terms of mass%, 0.05-0.3% carbon, 0.01-2.5% silicon, 0.5-3.5% manganese, 0.003-0.100% phosphorus, up to 0.02% sulfur, and 0.010-1.5% aluminum, provided that the sum of the silicon and the aluminum is 0.5-2.5%, with the remainder being iron and incidental impurities. The structure thereof comprises, in terms of areal proportion, at least 20% ferrite phase, up to 10% (including 0%) martensite phase, and 10-60% tempered martensite and has, in terms of volumetric proportion, 3-10% retained austenite phase, the retained austenite having anaverage crystal-grain diameter of 2.0 [mu]m or smaller. The retained austenite preferably has an average concentration of carbon in a solid solution state of 1% or higher.

Iron-based alloys and articles in strips, sheets, workpieces and the like are converted into high strength steel with a minimum of cost, time and effort, including producing dual phase materials. This is achievable by extremely rapid micro-treating of low, medium, and high carbon iron-based alloys and articles by rapid heating and rapid cooling at least a portion of the alloy/article. This heating step involves nearly immediately heating the iron-based alloy to a selected temperature above its austenite conversion temperature. Then, the alloy is immediately quenched, also at an extremely fast rate, on at least a portion of the iron-based alloy in a quenching unit adjacent the heating unit. This procedure forms high strength alloy in a desired area, depending upon where the treatment was performed.

A method of stress inducing transformation from the austenite phase to the martensite phase by conducting cold working on material of austenite stainless steel in the temperature range from the point Ms to the point Md. The above cold working is a biaxial tensing. An intermediately formed hollow body is made, which includes a ferromagnetic portion and a non-magnetic portion contracting inward. Then, the intermediately formed body is subjected to a stress removing process in which residual tensile stress is removed from an intermediately formed body. In the stress removing process, it is preferable that a punch is press-fitted into the intermediately formed body so as to expand a non-magnetic portion and then the intermediately formed body is drawn with ironing while the punch is inserted so that the residual tensile stress can be changed into the residual compressive stress in the non-magnetic portion.