227results about How to "Improve pitting resistance" patented technology

The invention discloses an aluminium alloy profile for a building template, and a preparation method thereof. The aluminium alloy profile comprises the following components in percentage by weight: 0.85-0.95 percent of magnesium, 0.06-0.65 percent of silicone, 0.15-0.20 percent of copper, 0.05-0.08 percent of manganese, 0.03-0.05 percent of zirconium, 0.04-0.06 percent of chromium, 0.008-0.012 percent of titanium, 0-0.2 percent of iron, 0-0.10 percent of zinc and the balance of aluminium. The aluminium alloy profile provided by the invention has the advantages that the tensile strength is more than 300 MPa, the yield strength is more than 260 MPa, the breakage elongation percentage is more than 12 percent, the tenacity, the weldability and the corrosion resistance are obviously improved compared with that of an original 6061 alloy, the pendulum impact value is more than 20 J / cm<2>, the welding coefficient is not less than 0.6, smaller quench sensitivity is provided, and critical quenching speed is dropped from 10 DEG C / S of the original alloy to 7 DEG C / S; during the processing of the aluminium alloy profile, air cooling is adopted to process an extrusion outlet with the temperature of 450 DEG C in a high-temperature segment as well as an extrusion outlet with the temperature of being smaller than or equal to 25 DEG C in a low-temperature segment, while a moderate-temperature segment, namely a quench sensitive area with the temperature of 450-250 DEG C utilizes water mist to replace direct water-cooling, so that the difficulty for controlling cross section deformation of the profile in the production field is greatly reduced.

A flux-cored wire for stainless steel arc welding including an outer sheath made of stainless steel and flux filled up in the outer sheath contains, as percentage to the total mass of the wire, Cr: 22.0-30.0 mass %, Ni: 6.0-12.0 mass %, Mo: 2.0-5.0 mass %, N: 0.20-0.35 mass %, TiO2: 4.0-9.0 mass %, SiO2: 0.1-2.0 mass %, ZrO2: 0.5-4.0 mass %, total of Li2O, Na2O and K2O: 0.50-1.50 mass %, metal fluoride in terms of fluorine amount: 0.10-0.90 mass %, and rare earth element component: 0.10-1.00 mass %, limits C to 0.04 mass % or below, W to 4.0 mass % or below, Cu to 2.0 mass % or below, Bi2O3 to 0.01 mass % or below, and limits oxides other than the above to 3.0 mass % or below. With such a composition, it is possible to obtain a weld bead which is excellent in the weldability in welding in all attitudes and is more excellent in the low temperature toughness while keeping excellent pitting corrosion resistance in arc welding of duplex stainless steel and the like.

The invention provides a manufacturing process of a pump body casting of a super duplex stainless steel centrifugal pump. The manufacturing process comprises steps of sand mould prefabricating, material smelting, casting, sand shakeout and heat treatment, wherein a runner core in a sand mould is composed of chromite furan resin sand of which the outer layer is filled with quartz furan resin sand;in material smelting, super duplex stainless steel material ZG00Cr25Ni7Mo4N is used, the chemical composition, ferrite content and PREN (Pitting Resistance Equivalent) value of molten steel are undercontrol and the casting temperature is from 1540 DEG C to1560 DEG C; after sand shakeout, forced air cooling is carried out, spray cooling is further carried out on the thick and large part of the casting, and after a casting system and a dead head are removed, the heat treatment is carried out. The pump body casting of a super duplex stainless steel centrifugal pump, which is manufactured by using the manufacturing method, has the advantages that the manufacturing and maintenance cost is reduced, abrasion resistance and pitting resistance are improved and the service life is prolonged.

The invention relates to an acidic coating super duplex stainless steel welding rod and belongs to welding material technology. The invention adopts 2507 duplex stainless steel wires as the welding core; the components and the weight percentages of the components of the welding rod coating are as follows: 30-40 of rutile, 3-7 of titanium dioxide, 15-20 of potash feldspar, 1-3 of phlogopite, 5-10 of marble, 16-20 of metal powder, 0.5-1.5 of rare earth fluoride, 2-3 of cryolite, 5-8 of chrome green, 0.5-1.0 of soda, and 1.5-3.5 of ferroalloy. The welding rod of the invention has the advantages, showed by the test results of manufacturability, metallographic observation, mechanical property and corrosion resistance, that the welding rod has extremely good welding technical property; electric arc is stable during welding, and spattering does not basically exist; the formation of weld joints is good; slag detachability is good; the manipulability of the welding rod is excellent; through metallographic observation, the content of ferrite in the structure of welding joints ranges from 40 percent to 60 percent, and the phase ratio can meet engineering application requirement; the welded welding joint has excellent mechanical property, and tensile strength can be more than 800 MPa; low temperature toughness is good; the stress corrosion resistance and pitting corrosion resistance of the welding joint are excellent.

The invention discloses a high-Zn, high-Mg and low-Cu ultrahigh-strength corrosion-resisting aluminum alloy and a heat treatment method. The alloy comprises the following components by mass percentage: 6.5-8.3% of Zn, 2.3-3.0% of Mg, 0.8-1.2% of Cu, 0.1-0.2% of Zr, less than 0.15% of Fe, less than 0.1% of Si, and the balance of Al. A preparation method of the alloy comprises the steps of blending, smelting, semi-continuous casting, homogenizing, thermoplastic deformation, short time solid solution, and ageing heat treatment. For the high-Zn, high-Mg and low-Cu ultrahigh-strength corrosion-resisting aluminum alloy prepared with the method, the hardness (HV) is 185-209, the tensile strength sigma b is greater than or equal to 650Mpa, the percentage elongation delta is greater than or equal to 7%, the pitting resistance is high, the cast ingot yield is high, and the stress corrosion resistance is further improved while the mechanical property is kept after multiple regression reageing treatment. The alloy and the heat treatment method solve the problems that the cast ingot yield in the existing high-copper Al-Zn-Mg-Cu ultrahigh-strength aluminium alloy is low, and the strength, toughness and corrosion resistance cannot be compromised. The heat treatment method is simple to operate, and the industrial production is facilitated.

The invention discloses a kernel I-grade 2209 double-phase stainless steel welding wire and a manufacturing method. The kernel I-grade 2209 double-phase stainless steel welding wire is prepared from the following components in percentage by mass: 0 to 0.03% of C, 0.5 to 2.0% of Mn, 0 to 0.90% of Si, 0 to 0.03% of S, 0 to 0.03% of P, 21.5 to 23.5% of Cr, 7.5 to 9.5% of Ni, 2.5 to 3.5% of Mo, 0.08 to 0.20% of N, 0 to 0.75% of Cu, and the balance of Fe. According the kernel I-grade 2209 double-phase stainless steel welding wire, alloy elements in an alloy system are reasonably mixed, so that the welding wire is high in process performance and mechanical performance, small in splashing, high in deslagging performance, outstanding in stress corrosion cracking resistance and pitting resistance; the alloy system is designed, so that the stable phase ratio of the weld joint metal is ensured; the manufacturing method is high in strength and high in plasticity of the manufactured welding wire.

The present invention discloses a kind of chlorine ion corrosion resisting nanometer composite Ni-Cr coating and its preparation and application. The nanometer composite Ni-Cr coating is prepared with nanometer metal Ni and Cr powder with Cr content of 4-15 wt%. The preparation process of the nanometer composite Ni-Cr coating is to electroplate Ni and Cr onto Ni substrate through conventional electric co-deposition. The nanometer composite Ni-Cr coating has obviously higher corrosion resistance than NiCr alloy with similar Cr content and composite Ni-Cr coating with micron Cr grains in similar content. The present invention has simple technological process, low cost, and compact and homogeneous coating. The nanometer composite Ni-Cr coating, when set in water solution containing Cl ion, will form hydrated Cr containing oxide and hydroxide to resist corrosion of Cl ion.