3403 results about "Austenitic stainless steel" 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 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.

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.

The invention provides a high-nitrogen austenitic stainless steel material for a vascular stent, which comprises the following chemical components in percentage by weight: 16-20% of Cr, 12-20% of Mn, 1-3% of Mo, 0.5-2% of Cu, no more than 0.05% of Ni, 0.7-1.2% of N, 0.5-8% of W, 0.05-0.5% of RE, no more than 0.08% of C, 0.3-4% of Si, no more than 0.010% of S, no more than 0.02% of P and the balance of Fe, wherein RE is a rare-earth element. The high-nitrogen stainless steel provided by the invention is mainly used for vascular stent processing; the elements of copper, nitrogen and rare earth are added to increase the blood compatibility of the stainless steel; and the tungsten alloy is added to increase the density of the stainless steel. The stainless steel has excellent visibility under X rays, contains no potential toxic element nickel, can be used in the aspects of surgical implants, medical appliances, food and catering appliances, jewelry and other stainless steel products which are always in contact with a human body, and can also be used in the fields of chemical engineering, environment protection and 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).

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.

The invention provides an integral manufacturing method of an S-04/S-08 high-strength stainless steel three-dimensional flow shrouded impeller. The integral manufacturing method comprises the steps of firstly, establishing an impeller three-dimensional model, and carrying out slicing treatment; determining the forming direction and support adding positions according to structural characteristics of the impeller; setting parameters of a laser selective melting forming processing technology according to characteristics of a high-strength stainless steel material; forming under protection of an inert gas; after forming, cleaning floating powder, removing a base plate through linear cutting, and removing supports; and finally, carrying out follow-up treatment such as surface treatment and thermal treatment on the impeller. According to the integral manufacturing method, complex cutters or fixtures do not need to be designed, materials can be directly added for part manufacturing only through the three-dimensional model of the impeller, the manufacturing cycle is greatly shortened, and the integral manufacturing method is applicable to trial manufacturing and middle and small-batch production in the development stage.

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.

A welding wire for austenitic stainless steel welding contains, in percent by mass, C: 0.005 through 0.05%, Si: 0.1 through 1.0%, Mn: 1.0 through 3.5%, Cr: 25.0 through 28.0%, Ni: 16.0 through 23.9%, Mo: 1.6 through 3.0%, Cu: 0.1 through 0.5%, Al: 0.001 through 0.02%, and N: more than 0.30 through 0.50%, limiting 0 to 0.03% or less, P to 0.03% or less, and S to 0.005% or less, and having a ratio of a Cr equivalent to Ni equivalent (Cr equivalent/Ni equivalent) within a range between 0.85 and 1.2 and a PI value of 35 or more, the remainder being iron and unavoidable impurities.

The invention discloses a girth welding technology for a vacuum container, which comprises the following steps: processing beveled edges, assembling and welding. In the step of processing the beveled edges, a 14mm thick 0Cr18Ni9 austenitic stainless steel material is selected as a cylinder base material, X-shaped beveled edges are adopted, an inside beveled edge is processed for 10mm with a single-side angle of 32.5 degrees, an outside beveled edge is processed for 4mm with a single-side angle of 35 degrees, and no truncated edge is left. In the step of assembling, reserved clearances of 2.0-2.5mm are assembled, argon tungsten-arc welding is adopted to position, a positioning welding length is 10-15mm, an interval is 200mm, and then a 'strut having a shape of Chinese character 'mi' which is used for adjusting the roundness of a cylinder is welded in the cylinder. In the step of welding, an argon arc welding double-gun butt-welding method is used for bottoming the interior of the cylinder, two layers are filled in an inner welding bead of the cylinder in the manner of manual arc welding, an external welding bead is covered in the manner of submerged-arc welding, and finally, the inner welding bead is covered in the manner of manual arc welding. The girth welding technology can be used for controlling the welding deformation and has the advantages that the method is simple and is easy to realize.

The invention provides alloy powder used for laser remanufacturing of FV520B martensitic stainless steel parts and a preparation method. The chemical components of the alloy powder include, by weight percentage, 0.01-0.3% of C, 12-17% of Cr, 3-7% of Ni, 0.4-2% of Mo, 0.1-2% of Mn, 0.15-0.55% of Nb, 0-3% of Cu, 0.05-2% of Si, 0-1.6% of B and the balance Fe. The preparation method of the alloy powder is a vacuum melting-high pressure gas atomization method. The alloy powder can have the density and the thermal expansion coefficient which are similar to those of FV520B materials when precipitation hardening elements, deoxygenation slag forming elements and elements used for lowering the martensite phase transformation point are added and the weight percent content of all the elements are regulated; the residual stress level is lowered through the martensite phase transformation accompanying effect; and therefore the problems of cracks, deformation and the like are greatly relieved, and the forming property, the anti-cracking property and the process stability are achieved and improved when the FV520B parts are subjected to laser remanufacturing through the alloy powder.

The invention discloses an austenitic stainless steel belt and a manufacturing method thereof. The invention is characterized by comprising the following chemical elements in terms of weight percentage: 0.04 to 0.12 percent of C, 0.4 to 1. percent of Si, 0.8 to 2 percent of Mn, less than or equal to 0.04 percent of P, less than or equal to 0.03 percent of S, 17 to 19 percent of Cr, 7 to 10 percent of Ni, 0.25 to 0.5 percent of Cu and the balance of Fe and inevitable impurities. The manufacturing method comprises the following steps: smelting; continuous casting with thin belts; control of cooling and winding; acid pickling, direct cold rolling and annealing; acid pickling again and cold rolling to achieve the thickness of a finished product; annealing after achieving the thickness of the finished belt steel, acid pickling, leveling, and length cutting into a finished coil. By utilizing the element of Cu, the invention reduces the use amount of Ni in the steel, reduces the production cost, simultaneously reduces the content of the residual ferrite in the steel, improves the wearing resistance of the steel, adopts direct cold rolling to match the high-temperature annealing procedure, and saves the procedures of hot rolling and solution treatment so as to lead the production process to be simple and stable.

The invention relates to production technology for inhibiting nickel-saving austenitic stainless steel hot-rolled plate edge crack, which comprises the following steps of: smelting and continuous casting, grinding plate blanks, heating blanks, rolling and the like. By controlling N content in steel below 0.13 percent, controlling Creq/Nieq within 1.35, controlling alpha-phase content in a casting blank texture within 4 percent, setting the reasonable heating temperature of plate blanks by combining on-site reality, and adopting the plate blank one-pass descaling box and frame final-pass descaling descaling technology, in particular the rolling technology of tightly combining hot-rolled rolling pass deformation and blank temperature, the production technology has the advantages of avoiding the edge crack of the produced stainless steel hot-rolled plates, obviously improving the yield, solving the problem of edge crack quality for steel coils in the rolling process through a steckel mill, guaranteeing the edge quality of the hot-rolled steel coils and improving the width yield of finished rolled plates.

The invention relates to a process for welding duplex stainless steel, in particular to the process for welding the duplex stainless steel used for high-sulfur content refining equipment, highly-corrosive petrochemical equipment and pipelines, high-parameter power devices, and the chloridion-corroded environments of seawater and the like. In the process, a specific protective gas favorable for the welding of the duplex stainless steel is adopted, and simultaneously limited linear energy and inter-layer temperature are regulated in the welding process, so that the unfavorable defects of the conventional welding process can be overcome, and a metallographic structure with the ferrite content of 30 to 70 percent and a ferritic phase in percentage equivalent to that of an austenitic phase is obtained. A welding joint obtained by the welding process has high mechanical properties, high strength and hardness, particularly high yield strength which is about twice that of austenitic stainless steel, high thermal fatigue resistance, pitting corrosion resistance, crevice corrosion resistance, intercrystalline corrosion resistance and high weldability.

The invention discloses a cold-rolled double-surface stainless steel composite plate having excellent comprehensive performances and a manufacturing method. The composite plate comprises a basal plate and a compound plate, wherein the upper and lower surfaces of the basal plate are wholly and continuously coated with the compound plate; the basal plate and the compound plate are formed to the cold-rolled double-surface stainless steel composite plate through an atomic diffusion metallurgical bonding method, wherein the basal plate is ultralow carbon aluminum killed steel; and the compound plate is 304 type austenitic stainless steel. The prepared cold-rolled double-surface stainless steel composite plate is excellent in surface quality and uniform in base material structure of carbon steel, has the room-temperature elongation above 45%, is excellent in corrosion resistance and stable in material performance, has the use performance of pure stainless steel, can largely reduce the cost, can serve as a substitute good of 304 stainless steel, and is widely applied to decoration panels and fields with higher forming requirements.

High performance coated metal compositions resistant to metal dusting corrosion and methods of providing such compositions are provided by the present invention. The coated metal compositions are represented by the structure (PQR), wherein P is an oxide layer at the surface of (PQR), Q is a coating metal layer interposed between P and R, and R is a base metal. P includes alumina, chromia, silica, mullite or mixtures thereof. Q includes Ni and Al, and at least one element selected from the group consisting of Cr, Si, Mn, Fe, Co, B, C, N, P, Ga, Ge, As, In, Sn, Sb, Pb, Sc, La, Y, Ce, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Ru, Rh, Ir, Pd, Pt, Cu, Ag, Au and mixtures thereof. R is selected from the group consisting of carbon steels, low chromium steels, ferritic stainless steels, austenetic stainless steels, duplex stainless steels, Inconel alloys, Incoloy alloys, Fe—Ni based alloys, Ni-based alloys and Co-based alloys. Advantages exhibited by the disclosed coated metal compositions include improved metal dusting corrosion resistance at high temperatures in carbon-supersaturated environments having relatively low oxygen partial pressures. The coated metal compositions are suitable for use in syngas generation process equipment.

The invention provides a high carbon high silicon martensite stainless steel billet. The steel billet is characterized by comprising the following components by weight percent: 0.41-0.47% of C, 2.80-3.20% of Si, 0.50-0.80% of Mn, 8.50-9.20% of Cr, 0.30% or less of Ni, 0.028% or less of P, 0.005% or less of S, 0.20% or less of W, 0.20% or less of Mo, 0.15% or less of V, 0.015% or less of Nb, 0.015% or less of Ti, 0.010% or less of Al and the balance Fe and inevitable impurities. The invention also provides a preparation method of the high carbon high silicon martensite stainless steel billet. The method comprises the following steps: performing primary smelting with an electric arc furnace (EAF), performing argon-oxygen decarburization (AOD) smelting, refining with a low frequency (LF) furnace, performing continuous casting, annealing and rolling. The method of the invention has simple operation, can stably control the quality of the continuous casting billet, completely suppresse cracks, overcome the defect of concentration of stress and increase the casting yield and quality stability of the martensite stainless steel.

The invention relates to a flux-cored wire for austenitic stainless steel all-position welding, and the flux-cored wire is composed of a flux core and an external stainless steel belt, wherein, the flux core accounts for 22-24wt% of the flux-cored wire, and the flux core comprises the following components in percentage by weight: 20-23% of metal chromium powder, 7-8.5% of metal nickel powder, 2-4% of electrolytic manganese metal, 3-4% of aluminium powder, 0.5-1% of ferrotitanium, 32-34% of rutile, 1-2% of quartz, 2-4% of zircon sand, 4-6% of albite, 2-4% of potassium feldspar, 1-1.5% of cryolite, 1-1.5% of lithium carbonate, 0.1-0.5% of bismuth oxide and the balance of iron powder. The ratio of the albite to the potassium feldspar in the flux core is 1.2-2, the sum of the albite and the potassium feldspar is not more than 10wt% of the flux core, the external stainless steel belt is the austenitic stainless steel 304L, the carbon content is less than 0.025wt%, the diameter of the flux-cored wire is 0.9-1.2mm, and the flux-cored wire can be used for realizing the austenitic stainless steel all-position welding.