145results about How to "Improve intergranular corrosion resistance" patented technology

The invention relates to a heating processing process for improving ageing strengthening type Al-Mg-Zn alloy intergranular corrosion performance, and belongs to the field of nonferrous metal and preparation of the nonferrous metal. According to the heating processing process, after an ageing strengthening type Al-Mg-Zn alloy is subject to solution hardening treatment, high temperature preageing treatment is carried out, in other words, heat preservation is carried out for 10 min to 3 h at the temperature ranging from 380 DEG C to 450 DEG C, quick quenching is carried out to the room temperature, then T6 peak aging treatment is carried out, two-step aging is carried out, heat preservation is firstly carried out for 12 h to 36 h at the temperature ranging from 60 DEG C to 100 DEG C, then heat preservation is carried out for 10 h to 40 h at the temperature ranging from 110 DEG C to 160 DEG C, and cooling is carried out to the room temperature. According to the heating processing process, alloy crystal boundary and crystal interior microstructures are changed, on the premise that the alloy strength and the extending rate are basically not lost, and the alloy intergranular corrosion resistance is remarkably improved; and in addition, compared with a traditional retrogression and reaging process, the process flow is greatly shortened, and industrial production is facilitated. The heating processing process has the important reference value on developing the novel high-strength corrosion-resistant ship and armored vehicle ageing strengthening type Al-Mg-Zn alloy.

The invention discloses low-nickel austenite gas valve alloy and a preparation method thereof. The low-nickel austenite gas valve alloy comprises the following ingredients in percentage by weight: 0.02-0.08% of C, 28.0-35.0% of Ni, 12.0-17.0% of Cr, 1.5-2.5% of Al, 2.5-3.5% of Ti, 0.4-1.02% of W and Mo, 0.3-0.9% of Nb and Cu, 0.05-0.2% of Y, 0.05-0.3% of Hf, 0.001-0.005% of B, smaller than or equal to 0.4% of Mn, smaller than or equal to 0.3% of Si, smaller than or equal to 0.02% of S, smaller than or equal to 0.02% of P, smaller than or equal to 0.02% of O, smaller than or equal to 0,02% of N and the balanced Fe and unavoidable impurities. Cu is smaller than or equal to 0.3%. The alloy has the advantages of high strength, excellent corrosion resisting property and good high-temperature performance.

The invention relates to an aluminum alloy tube resistant to seawater corrosion, in particular to an aluminum alloy tube with high seawater corrosion resistance. The aluminum alloy tube is manufactured from magnesium, aluminum and other raw materials through the steps of: melting, stirring, in-furnace modification treatment, impurity removal, fining treatment, online argon refining, purification treatment, casting, homogenization treatment, extrusion, cold drawing and the like. The aluminum alloy tube has the advantages of good seawater corrosion resistance and long service life, is particularly suitable for equipment for low-temperature multi-effect seawater distillation and seawater desalination treatment.

The invention belongs to the technical field of welding materials, which relates to an all-position niobium-contained stainless steel flux-cored wire. The flux-cored composition comprises the following components in percentage by weight: 2-10% of manganese, 8-15% of nickel, 20-35% of chromium, 2-9% of niobium-iron alloy in which the quantity of the niobium accounts for 70-80%, 20-45% of titanium dioxide, 2-6% of fluoride, 0.5-8% of magnesium oxide, 0.5-8% of silicon dioxide, 5-10% of titanium-iron alloy in which the percentage content of the titanium is 40-45%, 1-8% of Al2O3 and the balance iron powder. The flux-cored composition accounts for 16-30% of the total weight proportion of the flux-cored wire. The self-shielded flux-cored wire of the invention has excellent toughness and plasticity of weld metals, small splashing and good all-position welding performance, and obviously improves the slag removing performance and seam forming performance.

The invention relates to novel high-nitrogen austenitic stainless steel for a non-magnetic drill collar and a manufacturing method of the novel high-nitrogen austenitic stainless steel, and belongs to the technical field of stainless steel materials. The stainless steel comprises, by weight, 22.15-23.50% of Cr, 0.56-0.68% of Mo, 0.047-0.060% of C, 0.70-0.81% of N, 0.95-2.14% of Ni, 16.20-16.94% of Mn, 0.17-0.24% of Si, 0.008-0.010% of P, 0.008-0.012% of S, and the balance Fe, wherein the C+N is greater than or equal to 0.747% but smaller than or equal to 0.836% by weight, and Cr+3.3*Mo+16.0*N is greater than or equal to 35.0% by weight. The manufacturing method comprises the steps of non-vacuum induction melting, argon oxygen decarburization external refining, cogging by a quick forging press, molding by a radial forging machine, and water-cooling treatment. The novel high-nitrogen austenitic stainless steel for the non-magnetic drill collar has the advantages of excellent indoor temperature strength and intercrystalline corrosion resistance.

The invention belongs to the field of welding materials, and discloses an active solder for welding ferritic stainless steel with fined grains and a preparation method of the active solder. The active solder is formed by the following components of 8.77-9.77 mass percentage of Cr2O3, 5.27-6.27 mass percentage of TiO2, 6.53-7.53 mass percentage of SiO2, 49.33-53.33 mass percentage of CaF2, 14.60-16.60 mass percentage of NaF, 4.50-5.50 mass percentage of Ni, 4.50-5.50 mass percentage of TiFe and 0.80-1.20 mass percentage of Zr. By using the active solder disclosed by the invention, the fined grains at the welding seam of the ferritic stainless steel can be obviously fined, the mechanical properties of the welding seams can be improved, the intergranular corrosion-resistant capacity of the welding seams can be improved and the cost is low.

The invention provides a steam rotary drying system for ammonium salt and a method for preparing the ammonium salt. The steam rotary drying system is used in an ammonium salt drying process for the first time, a novel energy-saving and environmental-friendly ammonium salt drying technology is proposed, and the ammonium salt steam rotary drying system with the less moisture, low product breakage rate, high thermal efficiency, low power consumption, stable operation and energy conservation and the method for preparing the ammonium salt are provided. The steam rotary drying system for the ammonium salt comprises a feeding device, a steam rotary dryer, a conveying device, a vibration conveying cooling sieving machine and a tail gas dedusting device. The steam rotary dryer comprises a feeding cover, a rotary cylinder, a discharge cover, a transmission device and multiple heat exchange tubes arranged in the rotary cylinder. The hot air inlet of the steam rotary dryer is in a countercurrent mode.

Super wear-resistant steel with hardness not smaller than 400 HBW is prepared from, by weight percent, 0.10%-1.00% of C, 1.5%-3.5% of Si, 0.2%-0.8% of Mn, 0.20%-0.35% of Ti and 3.0%-8.0% of Cr. According to the production steps, a casting blank is heated after being formed through conventional smelting and pouring; double-pass high-pressure descaling is conducted till the surface is clean; hot rolling is conducted, and single-piece rolling is adopted; two-segment type cooling is adopted; and pit cooling is conducted till the room temperature. According to the super wear-resistant steel, by obtaining the metallographic structure of tempered martensite and ferrite, the brinell hardness can be larger than 400 HBW; and the corrosion rate does not exceed 0.04 mm/a under seawater soaking.

The utility model relates to a pressure-bearing header heat exchanger, which utilizes heating water for heat exchange to obtain hot tap water. Including: two headers, the header includes header shell, orifice plate and cover plate. Two or more tap water heat-absorbing pipes are fixedly connected between the two headers. The tap water heat-absorbing pipes are pierced with heating pipes. The heating pipes are connected. One end of the heating pipes is connected to the The heating water inlet is connected to the heating water outlet at the other end; one or more water blocking plates are arranged in one of the headers, and one or more water blocking plates are arranged in the other header. There are flanges around the water blocking plate, one side is welded on the orifice plate, and the other side is stuck or welded on the header shell. There are flanges around the cover plate, and the edges on both sides of the orifice plate are folded outwards, and the outwards folded edges on both sides of the orifice plate are welded and connected with the edge of the header shell plate. In the invention, the welded seam of the joint of the tube plate of the header shell is under pressure, the weld seam does not leak water, and the countercurrent heat exchange can also be realized.

The invention relates to a method for controlling grain boundary characteristics of austenitic stainless steel. The method comprises the following steps of: pre-processing the austenitic stainless steel, cutting the austenitic stainless steel into square blocks of the size of 40*40mm, and polishing the blocks with sand paper gradually to obtain No.800; then placing the pre-processed material on a laser processing workbench, regulating the output power, pulse width, light spot size and overlap ratio of a laser device, and carrying out laser impact processing on the surface of the material; and finally placing the material processed by laser impact in a heat treatment furnace, taking the material out of the furnace after warm preservation for water quenching so as to realize the control over the grain boundary characteristics of the austenitic stainless steel. The method can increase the intergranular corrosion resistance of the austenitic stainless steel, and can perform in-situ repair on an austenitic stainless steel member.

The invention provides a repair welding method of an austenite stainless steel casted nuclear pump shell. The repair welding method comprises the specific steps of defect detection and treatment; welding slot treatment; welding rod treatment: baking a welding rod at the temperature of 150 DEG C, and keeping the temperature for standby application; preheating of a to-be-welded zone; repair welding of the to-be-welded zone: carrying out repair welding layer by layer and pass by pass; confirmation of the repair welding effect: carrying out flaw detection on a repair welding zone of a pump body through rays, confirming the repair welding effect, and guaranteeing that the repair welding zone does not have weld defects; and solution treatment: carrying out solution treatment on workpieces subjected to repair welding. According to the repair welding method, samples do not have relatively large welding deformation through adoption of symmetrical arc-shaped welding slots, pre-welding preheating and postwelding thermal treatment; stress after repair welding is reasonably distributed through requirements on shape and radian of the welding slots and pre-welding thermal treatment; the content of impurity elements can be controlled and weld joints do not have obvious defects through surface roughness control and cleaning for the welding slots, and baking treatment for the welding rod; and intergranular corrosion resistance of austenite of the repair welding zone of a nuclear pump can be improved through postwelding solution treatment for a corresponding zone of the nuclear pump body.

The invention discloses a retrogression re-aging heat treatment technique suitable for Al-Mg-Zn alloy. The retrogression re-aging heat treatment technique suitable for the Al-Mg-Zn alloy comprises the steps that according to a pre-aging rule, heat preservation is conducted at the temperature of 80-220 DEG C for 15-50 h for one-stage or two-stage aging treatment, and cooling is conducted till the room temperature is reached, or furnace heating is conducted for retrogression aging; according to a retrogression aging rule, heat preservation is conducted at the temperature of 380-460 DEG C for 10 min-6 h, cooling is conducted till the room temperature is reached, and re-aging is conducted immediately; and re-aging is achieved through two sub-steps, heat preservation is conducted on the alloy at the temperature of 50-100 DEG C for 10-80 h in the first sub-step, heat preservation is conducted on the alloy at the temperature of 110-180 DEG C for 10-50 h in the second sub-step, and the alloy is cooled to the room temperature. According to the retrogression re-aging heat treatment technique suitable for the Al-Mg-Zn alloy, through the heat treatment way including pre-aging, high-temperature short-time retrogression and re-aging, the microstructure of the Al-Mg-Zn alloy can be obviously improved, a dispersing T-Mg32(AlZn)49 phase can be evenly separated out from the crystal of the alloy, the T-Mg32(AlZn)49 phase on the crystal boundary is distributed in an interrupted mode, and thus high strength is maintained; meanwhile, the intercrystalline corrosion resistance of the alloy is greatly improved, and the retrogression re-aging heat treatment technique has important reference value for developing novel high-strength and corrosion-resistant alloy for ships and armors.

The invention provides intergranular corrosion resistant Ni-saving type duplex stainless steel. The intergranular corrosion resistant Ni-saving type duplex stainless steel is prepared from the following chemical components in percentage by mass: 0.034 to 0.04 percent of C, 0.20 to 0.26 percent of Si, 5.9 to 14.6 percent of Mn, 22.30 to 23.69 percent of Cr, 2.12 to 2.40 percent of Ni, 1.20 to 1.41 percent of Mo, 0.10 to 0.14 percent of Cu, 0.26 to 0.28 percent of N, less than or equal to 0.008 percent of P, less than or equal to 0.006 percent of S and the balance of Fe and inevitable impurities. The invention further provides a preparation method of the intergranular corrosion resistant Ni-saving type duplex stainless steel, experimental steel is obtained through vacuum smelting and hot compression experiments, and the intergranular corrosion sensitivity of 23% Cr Ni-saving type duplex stainless steel solid solution state and hot compression samples with different Mn contents is tested through a double-ring potentiodynamic reactivation (DL-EPR). The relationship between the manganese content and the strain rate and the deformation temperature is regulated and controlled, the change trend of the corresponding intergranular corrosion sensitivity is analyzed, the influence rule of the deformation temperature, the strain rate and the Mn content change on the intergranular corrosion sensitivity is analyzed, and then the duplex stainless steel with good intergranular corrosion resistance under the condition of different Mn contents is obtained.

The invention discloses a grain boundary engineering technique for improving the corrosion resistance of 316Lmod stainless steel. The grain boundary engineering technique for improving the corrosion resistance of the 316Lmod stainless steel comprises the steps that heat preservation is conducted on the 316Lmod stainless steel at the temperature of 1050-1150 DEG C for 5-60 min; machining deformation with the deformation quantity being 3%-15% is conducted at the indoor temperature after water cooling; then annealing is conducted at the temperature of 1020-1150 DEG C for 3-12 min; and finally, the 316Lmod stainless steel with high corrosion resistance can be obtained after water cooling. According to the grain boundary engineering technique for improving the corrosion resistance of the 316Lmod stainless steel, the low sigma CSL grain boundary of the 316Lmod stainless steel can be improved remarkably; the components of materials do not need to be changed, and compared with an existing similar technique, long-time annealing is not needed, repeated machining and repeated annealing are not needed either, the technique is simpler, and operation is easy; the technique can also be referred and used for other several low-stacking fault energy face-centered cubic metal materials, cost control in industrial production is facilitated, popularization is easy, and extremely remarkable economic benefits are achieved.

The invention discloses a method for performing surface treatment on a golf head by forming a carbon, nitrogen, titanium and chromium composite coating. Under the vacuum condition, the pure metal such as titanium and chromium, and graphite are gasified and argon, nitrogen and acetylene gas are introduced so as to form plasma, and the carbon, nitrogen, titanium and chromium composite coating is formed on the surface of the golf head by a physical vapor deposition method according to an alloying principle. The golf head treated by the method has a pearlescent glossy black appearance, and high solvent resistance, corrosion resistance, impact resistance and metal adhesion firmness. Simultaneously, the coating has high comprehensive mechanical property, and certain hardness and toughness and completely meets the surface quality requirement of the golf head.

Provided is a method for optimizing grain boundary characteristic distribution of 316L austenitic stainless steel. The method includes the following steps that (1), the shape of a 316L stainless steelmember is adjusted, the upper and lower sides of the member need to be repaired to be flat and symmetrical; (2), the member is placed in a resistance furnace with the temperature being 1050-1150 DEGC for heat preservation for 60-90 minutes, and then material is taken out and subjected to water quenching; (3), the member is subjected to unidirectional compression deformation at room temperature,the deformation rate is 0.1-10 s<1>, and the deformation amount is 3%-6%; and (4), the deformed member is subjected to subsequent annealing treatment, the annealing temperature is controlled to 1080-1150 DEG C, and the annealing time is 90-110 min, and after the annealing is completed, the member is taken out and subjected to the water quenching. The optimized 316L austenitic stainless steel has alow [sigma] coincidence site lattice grain boundary ratio more than 80%, and the increase amplitude is significant; and multiple low [sigma] coincidence site lattice grain boundary clusters are formed, and the intergranular corrosion resistance performance of the material is significantly improved.

The invention discloses a thermal treatment method for improving performance of an aluminum alloy and a welding connector thereof. The thermal treatment method comprises the following step: sequentially carrying out solid dissolving treatment, water quenching and aging treatment on an aluminum alloy or a welding connector of the aluminum alloy. The thermal treatment method is characterized in thatthe aluminum alloy is a 6N01 aluminum alloy; the solid dissolving treatment temperature is 530-550 DEG C, the solid dissolving treatment time is 50-90 minutes, the aging treatment temperature is 155-180 DEG C, the aging treatment time is 2-13 hours, and the aluminum alloy is placed in the air for air cooling to the room temperature after the aging treatment. By adopting the method, thermal treatment modification is carried out on the 6N01 system aluminum alloys and welding connectors thereof, and on premise that the strength is not degraded, a breakage mode of the aluminum alloys is changed,and in addition, the intercrystalline corrosion resistance of the aluminum alloy can be improved.

The invention discloses a heat treatment method of an aluminum alloy. The heat treatment method comprises the steps that (1) an aluminum alloy plate is used as a raw material to be subjected to solid solution and quenching, the solid solution treatment temperature is 560 DEG C, and the solid solution holding time is 40 min; and (2) after solid solution and quenching, primary aging under the conditions of 135 DEG C and 6 h, secondary aging under the conditions of 170 DEG C and 8 h and tertiary aging under the conditions of 150 DEG C and 8 h are sequentially carried out, and aging is carried out in an air circulation furnace. The aluminum alloy plate is subjected to three levels of aging heat treatment, and the aluminum alloy with high intergranular corrosion resisting performance and strength can be obtained.