13results about How to "Avoid oxidation burn" patented technology

The invention provides a method for eliminating delta ferrite in austenitic stainless steel and the austenitic stainless steel, and belongs to the technical field of metal materials. The method comprises the following steps that an austenitic stainless steel ingot containing the delta ferrite is subjected to heat preservation for first set time at the first set temperature for first heat treatment; heating the austenitic stainless steel ingot subjected to the first heat treatment to a second set temperature, and carrying out heat preservation for a second set time at the second set temperature for second heat treatment; and cooling the austenitic stainless steel ingot subjected to the second heat treatment, or sequentially and repeatedly carrying out the first heat treatment and the second heat treatment on the austenitic stainless steel ingot subjected to the second heat treatment for at least one time, and then cooling to obtain the austenitic stainless steel subjected to delta ferrite elimination. The first heat treatment and the second heat treatment are performed, and the second set time is limited, so that the austenitic stainless steel is prevented from being in a high-temperature environment for a long time, and austenite grains are prevented from obviously growing.

The present invention provides a heat-resistant light magnesium alloy, which comprises, by mass percentage, 5.0-10.0% Li, 1.0-3.5% Mn, 0.5-2.0% Sn, 0.5-1.5% Sc, 0.5-1.0% Ce, the total amount of impurity elements Si, Fe, and Cu is less than 0.02%, and the balance is Mg. The present invention also provides a method for preparing the heat-resistant light magnesium alloy. The heat-resistant light magnesium alloy provided by the present invention has good thermal stability, and the preparation method of the heat-resistant light magnesium alloy provided by the present invention is simple and easy to operate, and easy to realize mass production.

The present application relates to the field of energy-saving and environment-friendly production technology, in particular to a calcination method and system for flow-suspension roasting of petroleum coke. The method comprises: feeding petroleum coke raw materials into a multi-stage preheating system for countercurrent preheating; after preheating, the materials enter a flow-suspension roasting furnace to form a suspension state in a high-temperature airflow for rapid roasting; after roasting, the materials are separated from the flue gas, the separated flue gas containing volatile components is combusted in a combustion furnace and then subjected to purification treatment, and the heat is partially recycled; the separated high-temperature calcined coke is cooled through an air cooling and water cooling system and the heat is recovered, and the hot air generated by air cooling is recycled to the roasting furnace. The present application uses fluidization technology to shorten the roasting time to seconds, significantly improving the production efficiency; through multi-stage countercurrent heat exchange, flue gas combustion and heat recycling, the present application realizes heat cascade utilization and precise atmosphere control, greatly reduces energy consumption and oxidation loss, and stably controls the volatile component of the product below 1%, with high yield and uniform quality.

The present invention provides a high-strength and tough lightweight magnesium alloy, which comprises, by mass percentage, 6.0-15.0% Li, 1.0-4.5% Ni, 1.0-5.0% Cd, 4.0-7.0% Zn, 0.5-5.0% Gd, 0.5-3.0% Sr, the total amount of impurity elements Si, Fe, and Cu is less than 0.02%, and Mg is the balance. The present invention also provides a method for preparing the high-strength and tough lightweight magnesium alloy. The high-strength and tough lightweight magnesium alloy provided by the present invention has high strength and good toughness, and the preparation method of the high-strength and tough lightweight magnesium alloy provided by the present invention is simple and easy, can be industrialized and mass-produced, and has low production cost.

A highly efficient and energy-saving ingot extraction protective atmosphere electroslag remelting equipment and method, belonging to the technical field of electroslag remelting, the equipment includes a power supply system, a furnace head car system, an ingot extraction system, a protective cover system and an automatic slag feeding system; the power supply system is electrically connected between the ingot extraction system and the furnace head car system; the protective cover system is arranged between the ingot extraction system and the furnace head car system; the automatic slag feeding system and the ingot extraction system are arranged in parallel. The present invention proposes a fully enclosed protective atmosphere electroslag remelting technology, which avoids electrode oxidation and oxidation and burning of easily oxidizable elements, and can obtain high-cleanliness steel ingots; the ingot extraction method of solid metal consumable electrodes combined with crystallizer lifting is used to produce electroslag castings, which can further improve production efficiency and yield while ensuring that the solidification quality of steel is not reduced. The length of the produced steel ingot can be up to 6180mm, and since the weight of the slag used to produce short steel ingots is basically the same as that used in traditional electroslag remelting, the cost of the electroslag remelting process can be greatly reduced.

The application provides a rare earth-titanium-boron composite vacuum seal welding high-density cored wire and a preparation method thereof, and belongs to the technical field of metallurgical auxiliary materials. The preparation method comprises the following steps: weighing lanthanum-cerium rare earth alloy powder, titanium powder and boron powder for batching, and then uniformly mixing under a protective atmosphere to obtain mixed powder; filling the mixed powder into a low-carbon steel cylinder after pretreatment under a protective atmosphere, and then preliminarily sealing to obtain a composite blank; performing a reduction reaction on the composite blank in hydrogen, and then performing seal welding under a vacuum condition to obtain a composite blank after vacuum seal welding; heating the composite blank after vacuum seal welding, and then performing hot drawing to obtain the cored wire. The cored wire provided by the application realizes stable composite addition of rare earth, titanium and boron with high recovery rate, and significantly improves the structure and performance of 20Mn2 steel and the like, and solves the problems of cold heading cracking, insufficient toughness and aging embrittlement.

The invention relates to a method for reducing the forging oxidation burning loss of an NbZrTi series refractory high-entropy alloy, and belongs to the technical field of alloys. Raw materials of all elements in the NbZrTi series refractory high-entropy alloy are weighed according to the atomic percent, vacuum consumable smelting is carried out, and an obtained bar is subjected to three-heating-number forging; the method comprises the steps that the surface of a bar is coated with a high-temperature anti-oxidation coating in a brushing mode before each heating number of forging, after each heating number of calcining is completed, the bar is placed in a closed device which is provided with a circulating cooling water structure and is filled with argon to be cooled, after the last time of cooling is completed, oxide skin of the whole body is polished, and the NbZrTi series refractory high-entropy alloy forge piece bar with the low oxidation loss rate is obtained. The oxidation burn-out rate of the NbZrTi series refractory high-entropy alloy in the forging process is effectively reduced and the grain size is refined by optimizing the alloy components and the forging process.

The application relates to the technical field of alloy materials, in particular to a 4341E high-speed steel and a preparation method thereof. The high-speed steel is characterized in that Ti, B and N elements are introduced for ternary micro-alloying and synergistic modification on the basis of a W-Mo-V-Co component system, nanoscale particles generated in-situ by Ti-N are used as heterogeneous cores to significantly refine grains, the grain boundary is strengthened by the grain boundary segregation effect of boron elements, and the reticular carbide is effectively broken. The obtained steel material realizes perfect matching of high hardness, excellent red hardness and excellent impact toughness, solves the problem that the strength and toughness of traditional high-speed steel are difficult to be compatible, and is particularly suitable for manufacturing high-performance cutting tools, cold and hot precision dies and high-temperature wear-resistant parts.

The invention relates to a method for reducing the oxidation and burning loss of NbZrTi series refractory high entropy alloy during forging, and belongs to the technical field of alloys. The raw materials of each element in the NbZrTi series refractory high entropy alloy are weighed according to the atomic percentage, and vacuum consumable smelting is performed to obtain a rod forged in three fires; before each fire forging, a high-temperature anti-oxidation coating is brushed on the surface of the rod, and after each fire calcination, the rod is placed in a closed device with a circulating cooling water structure and argon gas is introduced for cooling. After the last cooling, the oxide scale is polished all over to obtain a NbZrTi series refractory high entropy alloy forging rod with a low oxidation loss rate. By optimizing the alloy composition and forging process, the oxidation and burning loss rate of the NbZrTi series refractory high entropy alloy during the forging process is effectively reduced and the grain size is refined.

The application discloses a kind of plasma arc welding torch, to solve the technical problems of poor cooling effect of existing welding torch, nozzle disassembly and maintenance are complicated, tungsten needle is low, the service life of gun body is short.It includes gun body assembly and the gun head assembly detachably mounted on gun body assembly, tungsten needle, centering device, nozzle, tungsten needle limiting component and cooling waterway component are arranged in gun head assembly;Cooling waterway component constructs independent negative electrode, positive electrode double cooling waterway, adopts sectional type surrounding flow channel design;Nozzle is provided with annular positioning boss, and forms two-stage coaxial limiting system with centering device, gun body assembly integrates independent ion gas, double gas path structure of shielding gas, and the tail of gun adopts integrated linkage quick-release structure.The application greatly improves the cooling efficiency of welding torch and the centering accuracy of tungsten needle under the premise of ensuring compact structure, realizes quick disassembly and maintenance of wearing parts, effectively prolongs the service life of welding torch, and can be widely adapted to various high-load continuous welding industrial scenes.

This invention discloses an exothermic welding device for zinc-clad steel grounding electrodes of buried gas pipelines, belonging to the field of exothermic welding technology. Molten metal inside the reaction chamber flows into the welding cavity through a guide hole. A first interface channel for inserting the zinc-clad steel grounding electrode is machined on one side of the welding mold. A squeezing and vibration mechanism located on the outer circumference of the zinc-clad steel grounding electrode is installed inside the first interface channel. A second interface channel for inserting a connecting wire is machined on the other side of the welding mold. One end of the zinc-clad steel grounding electrode inside the welding cavity is connected to one end of the connecting wire to form the welding part. This invention, through inert gas pre-purging, can completely remove air from the welding cavity, avoiding oxidation and burn-off of the molten copper at temperatures above 2000℃ upon contact with air. This effectively reduces defects such as porosity and oxide inclusions inside the weld. The molten copper solidifies stably in an inert environment, forming a metallurgical-grade cast-welded connection, with stable and reliable conductivity and mechanical strength of the joint.

The investment precision casting process comprises the following steps that firstly, a hollow workpiece wax mold is prepared, a water-soluble core is prefabricated, the two ends of the water-soluble core are clamped through a blade body mold, a plurality of supporting points used for supporting the water-soluble core are arranged on the portion, located on the inner side of a cavity, of the blade body mold, and the water-soluble core is supported by the supporting points; wax is injected into the cavity, and a wax mold with a water-soluble core is obtained; 2, a hollow workpiece wax mold is extracted, the water-soluble core is hydrolyzed, and the hollow workpiece wax mold is obtained; 3, wax mold inner cavity mold core preparation and shell manufacturing are conducted, specifically, the surface of the wax mold in the step 2 is dip-coated with multiple layers of slurry and powder, blowing drying is conducted to form the shell, semi-self-hardening refractory slurry is poured into the shell, and a hard mold core is formed to resist erosion and acting force of molten steel during pouring; 4, dewaxing, smelting and casting; and 5, cleaning and shaping a casting and carrying out a subsequent heat treatment process, so that a formed workpiece is obtained. And sixthly, the performance quality inspection procedure is conducted on the formed workpiece in the fifth step.

The invention discloses a control method for reducing oxidation burning loss of a double-heat-storage walking beam furnace, which belongs to the technical field of large plate blank heating furnaces and comprises the following steps: controlling the temperature of a hearth according to the rolling specification of a plate blank, controlling the temperature of a first heating section to be 1000-1050 DEG C, the temperature of a second heating section to be 1150-1200 DEG C, the temperature of a third heating section to be 1250-1300 DEG C and the temperature of a soaking section to be 1250-1280 DEG C; the CO content range in the high-conversion mixed gas is controlled to be 26-32%, and the residual oxygen content in the flue gas is controlled to be less than 8%; controlling the air-coal ratio of the first heating section to be 0.8-0.95, the air-coal ratio of the second heating section to be 0.8-0.95, the air-coal ratio of the third heating section to be 0.9-1.0 and the air-coal ratio of the soaking section to be 0.8-0.9; the cold blank and the hot blank are separately charged into a furnace, the time of the hot blank in the furnace is controlled to be 120-140 minutes, and the time of the cold blank in the furnace is controlled to be 160-180 minutes; the technical problem of oxidation burning loss in steel rolling production is solved.