CN112941420A - High-strength impact-resistant heat-resistant low-temperature-resistant alloy steel and manufacturing process thereof - Google Patents
High-strength impact-resistant heat-resistant low-temperature-resistant alloy steel and manufacturing process thereof Download PDFInfo
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- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
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Abstract
The invention discloses high-strength impact-resistant heat-resistant low-temperature-resistant alloy steel and a manufacturing process thereof. It has good castability,Heat treatability, workability, and weldability. The hollow crankshaft is widely used for manufacturing hollow crankshafts with complex shapes in petrochemical oil production equipment, hollow shafts in tubular mills in mines and metallurgical equipment and important parts of gears, discs or rings which are cast instead of forged, wherein the hollow crankshafts have high strength, impact resistance, wear resistance, low temperature resistance and corrosion resistance and need to be used for manufacturing gears, discs or rings, and the hollow crankshafts have complex shapes in petrochemical oil production equipment and are subjected to cold and hot working at the temperature of below 500 ℃ or between 500 ℃ and-50 ℃. The main properties of the steel of the invention are as follows: yield strength of BBs ═ (756-813) N/mm2The impact toughness alpha ku is (61-69) J/cm2At-50 deg.C,. alpha.ku ═ 45-53J/cm2(ii) a Compared with the existing ZG35SiMn which is applied more, the yield strength is improved by 86.8%, the toughness is improved by 85.7%, the product performance of the product of the country company is improved by 12.07%, the alpha ku is improved by 47.73%, and if the product price is reduced by 45% (namely 6.6 ten thousand yuan/T) according to the import product price (12 ten thousand yuan/T), the product export 15000T can earn about 1.5 billion dollars each year.
Description
Technical Field
The invention relates to a low-alloy cast steel with high strength, impact resistance, heat resistance and low temperature resistance, which can be widely used for manufacturing large and small gears, gear rings, heavy-load traveling crane and tower crane rollers, riding wheels, wheel belts and heavy-load gear rings in large rotary kilns in industrial equipment such as petrifaction, mines, metallurgy, ships, transportation, electric power, building materials, machinery and the like; an end disc, a hammer disc, a speed reducer gear and a large flywheel in the hammer crusher; hollow shafts in various tubular mills and large gear rings in edge transmission; vital sprockets in various types of conveyors; important parts at the high end such as a hollow crankshaft of petrochemical equipment, a gear, a large cutter head … … of a shield machine and the like; the invention also relates to a manufacturing process of the low alloy steel with high strength, impact resistance, heat resistance and low temperature resistance.
Technical Field
In the prior art, alloy cast steel blanks of all countries all over the world generally exist to different degrees: casting defects such as air holes, sand inclusion or slag inclusion, shrinkage cavities, segregation or cracks and the like; the main performance problems of at least 95% of the world with alloy cast steel products are: the yield strength (bps) is low, the impact toughness (alpha ku) is poor, the low-temperature resistance toughness is worse or is not involved in research, and the importance of the low-temperature resistance toughness is not known at all; however, with the development of industrial equipment in various countries in the world, the demand for improving various performances of oceans, petrochemicals and national defense, and the research and experiments on low-temperature toughness, heat resistance, wear resistance, corrosion resistance and weldability of various alloy steels (including forged steel or cast steel) in Germany, Sweden, Japan and other countries with the scientific development of materials have invested a lot of manpower and financial resources and have achieved obvious effects; the inventor of the present invention has seen in 95-2001 in Guangdong Shaoshaoguan, a cake-shaped member (about size: phi 900 (outside diameter) × 130mm (thickness)]The appearance quality is good (the unit price of Chenghangjiangzhu and the general affair side Yao grammar at the sale position: 9600 yuan/T), the supply quantity: 1000 tons/month; according to the factory main process, the Jiang has already said that: japanese requires that the product performance of the product, namely the product, is not less than 685N/mm2，αku≥40J/cm2，αku (-40℃)≥27J/cm2… …, acceptance, payment and delivery.
The inadaptability of important alloy cast steel part products to the application working conditions is very common and sometimes serious; the method is mainly characterized in that the method is invited by a plurality of users to analyze the reasons of production site help, so that the technical quality problem is solved, and the following examples are selected:
1. the Guangxi red river cement plant (modified Guangxi Huarun red river cement Co., Ltd.) entrusts a mechanical plant to produce 4 hollow shafts (material ZG40Cr) of the drying mill, wherein 2-5 cracks are generated on each hollow shaft in half a month when two hollow shafts are operated on the machine; according to the introduction of production site and operators, the flange planes at the left and right ends of the cylinder body of the drying and grinding machine are respectively locked with the large-end flange planes of the two hollow shafts by a plurality of reamed hole bolts; the bearing surface on the excircle of the thin-walled cylindrical outer surface of the hollow shaft is supported by the semi-contained shape of the equal-diameter Babbitt metal bearing surface in the spherical bearing with equal height at the two ends; when the mill is in rotation, the hollow shaft is subject to the oscillating collision impact which is periodically changed, wherein the total weight of the mill cylinder, the high manganese steel full-lining plate, the grinding body, the steel ball or steel bar, the ground material and the like is about one hundred tons, and the hollow shaft continuously performs collision grinding, lifting (instantaneous weight reduction) and falling (sudden impact) along with the rotation of the cylinder (n is 17.7 revolutions per minute), and then enters collision grinding.
Regarding the application condition of the drying and grinding machine determined by the production process, the drying and grinding machine (namely, the materials are dried by blowing hot air with the temperature of 350-420 ℃ while being ground and refined) also has the heat effect similar to medium-temperature tempering, the exposed hollow shaft has the outer diameter which is subjected to severe cold of about-10 ℃ in winter in the south, the internal heat and the external cold are simultaneously interwoven to cause internal and external cold contraction and thermal expansion to form great contrast, and if the casting internal defects or casting, repair welding and processing stress of the R120 region of the root part are not removed, the hollow shaft is inevitably broken under heavy load with strong impact and vibration. Then entrust our company to make 2 pieces by the company of the invention, adopt the technology of the middle period of the steel (06-4-16) to produce two pieces (about 7; then the production of 4 products is entrusted by cement plants in Jiangshan of Zhejiang; the forging piece reaches the level II of the forging piece after 100 percent of super detection during delivery, and is well commented by a plurality of users!
2. Guangxi Huarun Hongshui riverA hammer crusher with 2 meters multiplied by 2.4 meters (improved type) is used in a mine phi 2 meters multiplied by 2.4 meters (modified type) of a cement company Limited, an end disc (originally 1.1 ton/piece multiplied by 2 pieces/set, and then 985 kg/piece) and a hammer disc (0.5 ton/piece multiplied by 12 pieces/set) are used, original paper ZG35SiMn is mostly manufactured in 'Luo mine', the original paper ZG35SiMn is changed once in 30-45 days of service life, and the original paper ZG35SiMn is mainly non-wear-resistant and easy to break … …; according to the worn and broken end disc and the hammer disc and the analysis of the combined drawing: after being quenched and tempered, ZG35SiMn has the yield strength of 420N/mm2The impact toughness is also not high only: alpha ku-35J/cm2Mechanical parts made of ZG35SiMn can only bear circumferential and repeated stable friction and smaller impact; and 6 pieces of hammerheads (132 kg/piece, 41.5 m/s of V line) in each row in a large crushing bin with the diameter of 2m multiplied by 2.4 m are continuously crushed for 1.1 m multiplied by 1.1 m (the extrusion strength is 2000 kg/dm)2) The breaking force of the large green stone reaches 3145 tons, and all the broken stones with different sizes continuously impact the hammer disc and the end disc like bullets, so the hammer disc and the end disc made of ZG35SiMn are easy to crack and cannot resist wear and impact. Then, the end disc and the hammer disc are manufactured by the company by adopting the invention steel (06-4-16), and the service life reaches more than 180 days; the product is good for users and is supplied without inspection at fixed points for 4 years.
3. Because a user entrusts a certain large national enterprise in Shanghai to break a double rotor (17 tons/pair) by the phi 1250 multiplied by 1250 impact produced by Jiangxi Yushan mine, a hexagonal rotor body is broken (the linear velocity V is 44.5 m/s, the original rotor body is cast steel by ZG35, and a main shaft is cast steel by 40Cr), the production is stopped for 2 months; according to the observation and analysis of the fracture of the hexagonal rotor body on site: the fracture has air holes and internal cracks of old rust, which indicates that the product is not subjected to over-detection when leaving the factory; in addition, the ZG35 cast steel has too low yield strength after normalizing and tempering (BBs 270N/mm)2) Then competitive bidding is carried out by a Tangshan water machine, a Shanghai heavy machinery factory and a Shenyang gear factory, and the company wins the supply right; the invention (06-4-16) is used in the middle stage of the research test by the company, and the main performance of the cast steel product and the furnace test piece (BBs) is 665N/mm2，αku＝68.6J/cm2) Three pairs are produced for Zhejiang and one pair is produced for Anhui nested lake; the rotor body adopts the invention (06-4-16), the main shaft adopts 35CrMoV forged steel for hardening and tempering, the inner step holes phi 325 and phi 330 are in corresponding interference with the main shaftThe amount is 0.18-0.22 mm; after hot charging, the static balance error is less than or equal to delta 130 g; after both the supply and demand parties report and check, the user is satisfied and the use is not bad for many years! Thereafter, Zhejiang users entrust my company to produce 6 DV-31 mill speed reducers and bull gear rings and paired pinion gears … … of a multi-piece edge drive type mill; after the product is delivered and used for 12 months, no product quality appears, and the user pays out all large amount of ordered goods.
4. According to the fact that the responsible person of a large national enterprise in the Lanzhou says that: they receive a large amount of slurry pumps for petroleum drilling, and are provided with three hollow three eccentric shafts F1200, Fe1400 and F1600, and matched gear rings and gear shafts; the problems are that: the product is qualified in Lanzhou detection, after how the product is transported to northwest Liya, the equipment is not moved, a large number of hollow eccentric crankshafts are cracked … …, and the first batch of hollow eccentric crankshafts are made of ZG 40; the second batch entrusts the Deyang second rework after returning the goods, so that two months are spent, and as a result, the 'double' drawing is mistaken, 6 pieces are processed and discarded for ten pieces, 4 pieces are processed, and the defects of the castings are … …; according to the introduction of the technology of a large enterprise and a production responsible person in a certain state of Lanzhou and the communication of the technical process of a drawing, the reason why 30 sets of hollow eccentric crankshafts, such as F1200 and the like, for petroleum extraction applied to northwest, which constitute export to Russia, are unqualified is analyzed as follows: (1) the blank is not subjected to dehydrogenation annealing after being unpacked; (2) after rough turning, shallow air holes are found not to be thoroughly dug and repaired, so that the steel wire is returned, and after tempering and finish machining, air holes and a small amount of cracks are found; (3) the cracks after finish machining are only superficially repaired and polished, and the dispersed air holes are only filled with cast iron sand glue; casting stresses and machining and welding stresses then remain inside the product; (4) even the qualified ZG40Cr can be used for the treatment of the after-normalizing and tempering BBs of 480N/mm2Left and right,. alpha.ku ═ 28-33J/cm2(ii) a The strong use can be avoided only under the working condition within minus 20 ℃; at the temperature of between 50 and 60 ℃, the ZG40Cr has greatly reduced toughness and generates chilled deformation, and is continuously and intensively impacted at the temperature of between 50 and 60 ℃ to leave internal defects, so that the product is subjected to cold and chilled deformation in severe cold, and cannot be returned to … … due to brittle fracture after being stressed.
In summary, it has been fully shown that: the design level, the production technical level and the application technical analysis level of the low-alloy cast steel in China are still quite lagged behind; the Q/ZB66-73 and JB/T5000.6-2007 standards of the Chinese alloy cast steel are read through, and the 21 listed alloy cast steels are found to have generally low performance and serious insufficient impact toughness, and the low-temperature toughness is no … … at all, so that the search, development and research of novel high-strength, impact-resistant and low-temperature-resistant multifunctional special alloy cast steel to meet the requirements of industrial construction and the improvement of the performances of marine, petrochemical and national defense equipment is urgent!
Disclosure of Invention
The invention aims to provide a low-alloy cast steel with high strength, impact resistance, heat resistance and low temperature resistance, which has the characteristics of no casting defects such as air holes, no cracks, no sand inclusion and the like, high strength, impact resistance, heat resistance, low temperature resistance and corrosion resistance, has low manufacturing and using cost, and fully meets the requirements of wide application of various modern large-scale industrial mechanical equipment and important parts.
Another object of the present invention is to provide a process for producing a low-alloy cast steel having high strength, impact resistance, heat resistance and low temperature resistance.
(code 2016-10-7) the forging product has the following main properties: BBs ═ N/mm (1105-2，Бb＝(1180-1270)N/mm2，δ≥14％，αku＝(101.25-113.75)J/cm2，αku (-50℃)＝(89-98)J/cm2(ii) a The performance detection is carried out on the corresponding cast steel, and the main performance data is as follows: BBs ═ (756 once 813) N/mm2，Бb＝(826-895)N/mm2，αku＝(61-69)J/cm2At-50,. alpha.ku ═ 45-53J/cm2，
The invention selects C, Si, Mn, Cr and Mo as main additive elements. A small amount of V, Nb, N, Zr, Ti and RE elements are added; it is a multifunctional special steel with low alloy and inherent property, so that it possesses good castability, repair welding property, heat treatment and working property and corrosion resistance.
The technical key is that the castability defect of the blank is avoided or reduced, the qualification rate of the blank is improved, and the manufacturing cost is reduced. The cast steel blank is annealed, roughly processed, quenched and tempered, and the microstructure of the cast steel blank is uniform and fine high-strength and high-toughness sorbite in which dotted carbides and nitrides are dispersed. It has high strength, hardness and wear resistance, and has good impact toughness, corrosion resistance and heat resistance, and the comprehensive mechanical performance of the cast steel product is far superior to that of many existing forged steel products, so that the cast steel product can be objectively and completely 'cast instead of forged'; so far, no material which is more suitable for manufacturing various large-scale important mechanical equipment and parts than the material is found at home and abroad. The cast steel comprises the following components in percentage by mass:
carbon (C): 0.26-0.42; silicon (Si): 0.40-0.75; manganese (Mn): 0.65-1.25; chromium (Cr): 0.9-1.4; molybdenum (Mo): 0.5-0.85; vanadium (V): 0.30-0.65; niobium (Nb): 0.2-0.42; nitrogen (N) is less than or equal to 0.15; titanium (Ti) is less than or equal to 0.18;
zirconium (Zr) is less than or equal to 0.18; rare earth element (RE) is less than or equal to 0.18; phosphorus (P) is less than or equal to 0.02; sulfur (S) is less than or equal to 0.02; iron (Fe): 96.06-93.53;
and the chemical composition technical characteristics that at least one of the four elements of nitrogen (N), titanium (Ti), zirconium (Zr) and rare earth element (RE) in the components is not zero, and the balance is Fe.
In the present invention, a part of carbon (C) is dissolved in α -Fe to form a ferrite solid solution and Fe forms cementite (Fe)3C) C also forms alloy carbide with excessive alloy elements dissolved in ferrite, wherein the alloy carbide has high hardness and is heat-resistant and wear-resistant: VC, NbC, TiC, ZrC and Mo2C、Mn7C3、Cr7C3(ii) a While carbon is dissolved in cementite (Fe)3C) The alloy elements jointly form an alloy cementite with complex crystal lattices: (Fe. Cr)3C、(Fe·Mn)3C、(Fe·Mo)3C、(Fe·Cr)23C6、(Fe·Mo)23C6、(Fe·V)3C、(Fe·V)23C6Etc.; these homogeneously dispersed carbides, on the one hand, strongly impede the growth of the high-temperature austenite grains, thus increasing the temperature point for complete austenitization, in order to minimize the sorbite grains obtained after the heat treatment: grain size of 20-um2It has enough strength, hardness and good impact toughness, and its carbon content is controlled between 0.26% and 0.42% in the invention.
Silicon (Si) is usually added as a deoxidizer, and when the content is less than or equal to 0.85 percent, the Si is completely dissolved in ferrite, so that the strength and the hardness of the ferrite are enhanced strongly, and the toughness change is very small; when the content is more than 0.85%, the toughness is remarkably reduced; however, Si not only improves the tempering stability, but also increases the fluidity of molten steel and improves the casting performance. Therefore, the content of Si in the present invention is controlled between 0.4% and 0.75%.
Manganese (Mn) is dissolved in ferrite to form alloy ferrite alpha-Fe (Mn) and alloy carbide Mn7C3And alloy cementite (Fe. Mn)3C is an important element for improving hardenability, homogenizing tissues and improving strength, hardness and toughness; in addition, Mn can form MnS with impurities S to be removed by slag, so Mn has the functions of purifying molten steel and removing impurities automatically. Meanwhile, Mn is also a good deoxidizer, reduces the brittleness of steel and improves the quality of the steel. When Mn is contained in<At 0.9%, the strength and hardness of the steel increase with the increase of the content thereof, and the impact toughness varies slightly within this range; but when Mn content is large>At 1.5%, the impact toughness drops sharply. In order to achieve the strengthening effect and not to reduce the toughness greatly, the Mn content is controlled between 0.65% and 1.25%.
Chromium (Cr) and molybdenum (Mo) are partially dissolved in ferrite to form alloy ferrite alpha-Fe (Cr), alpha-Fe (Mo); the other part forms fine-grained, dispersed stable alloy carbides; cr (chromium) component7C3、Mo2C; and a part dissolved in cementite (Fe)3C) And, stabilizing the alloy cementite in a fine, dispersed and diffused manner: (Fe. Cr)3C、(Fe·Mo)3C、(Fe·Cr)23C6The equal state exists in the grain boundary and among the grain boundaries of the high-temperature austenite, which not only prevents the growth of austenite grains, but also lays a good foundation for obtaining uniform fine grain sorbite tissues after quenching and tempering, thereby obviously improving the strength, hardness, wear resistance and high-temperature oxidation resistance of the high-temperature austenite; meanwhile, the reasonable combination of Cr and Mo also has the function of shifting the C curve to the right to obviously improve the hardenability, and improves the tempering stability, strength, hardness and wear resistance; the addition of Mo, Ti, Zr and RE effectively reduces the temper brittleness; when the content of Cr element is less than or equal to 1 percent, the alloyThe strength, hardness and impact toughness increase with the increase of Cr content, but when the content is 1%<When Cr is less than or equal to 2%, the impact toughness of steel is slightly reduced, and when Cr is contained>When the Cr content is 2%, the strength and the impact toughness are obviously reduced, so that the Cr content is controlled to be 0.9-1.4% in the invention;
when the Mo content is less than or equal to 5%, the strength and hardness of the steel increase with the Mo content, but the toughness of the steel increases from 245J/cm with the Mo content2Sharply decreases to 63.7J/cm2Especially when the steel contains Mo>When the content is 1.7%, the toughness is reduced remarkably; in addition, the addition of Mo, Ti and Nb effectively improves the tempering stability and greatly improves the strength of the steel after tempering; therefore, the Mo content should be controlled between 0.5% -0.85% in the present invention.
Vanadium (V) and niobium (Nb), V, Nb exist in austenite alloy steel in the form of dispersed fine Vanadium Carbide (VC) and niobium carbide (NbC) in and between austenite grain boundaries, and strongly hinder the growth of austenite grains; v, Nb the trace addition is helpful to greatly improve the high temperature strength and the tempering stability of the finished product and increase the impact toughness and the low temperature resistance toughness. In order to comprehensively consider all element composition ratios and required strength, toughness and low temperature resistance, the invention confirms that the content of V is as follows: 0.30% -0.65%; the content of Nb is: 0.2 to 0.42 percent.
Zirconium (Zr), titanium (Ti), Zr, Ti and C exist in grain boundary of high-temperature austenite and among grain boundary in dispersed and fine zirconium carbide (ZrC) and titanium carbide (TiC), so that the growth of the grain is effectively prevented, and the hardenability, tempering stability, weldability of the finished product and high-temperature strength are enhanced. In order to obtain the tempered sorbite with fine grains and high strength and higher heat resistance and impact toughness, the invention confirms that the content of Zr is less than or equal to 0.18 percent and the content of Ti is less than or equal to 0.18 percent.
The dissolving amount of nitrogen (N) and N in alpha-Fe and gamma-Fe reaches 0.1 percent and 2.8 percent respectively, and the nitrogen (N) and the N in high-temperature austenite partially compete for part of alloy elements: such as: v, Nb, Zr, Ti, Mo, etc. form heat-resistant and hardly decomposed nitrides: VN, NbN, Nb2N、ZrN、TiN、Cr2N, etc. dispersed as fine particles in and between the grain boundaries of austenite to strongly inhibitGrowing austenite grains; the high-temperature resistant strength of the finished product and the hardness and the wear resistance of the finally obtained tissue sorbite are greatly improved. The addition of N reduces the content of C elements which are unfavorable for welding; n enables the Ms temperature point to move downwards, so that the hardenability and strength of the austenitic alloy steel are improved; thereby the obtained austenite has good toughness, low temperature resistance and weldability. However, excessive N causes pores in the cast slab, so that the N content in the invention is determined as follows: less than or equal to 0.18 percent.
The addition of rare earth element (RE) in small amount can raise toughness and weldability, and has the functions of desulfurizing S, degassing and eliminating harmful impurity. In the present invention, it was confirmed that: the RE content is less than or equal to 0.18 percent.
Phosphorus (P), sulfur (S), P, S present many of the same hazards in austenitic steels: c, Mn elements are promoted to generate segregation, S exists in the form of FeS and MnS in the austenitic alloy steel, and enters slag in the form of MnS; but FeS and Fe can exist eutectic with low melting point and are distributed on grain boundaries, so that the bonding force between the grain boundaries is weakened, and the steel is easy to crack and damage when being stressed in a hot state; in addition, P also tends to promote the growth of austenite grains, so that the P, S content in the present invention is considered to be: less than or equal to 0.02 percent.
The corrosion resistance of the invention is quite obvious, such as: the addition of Cr, Ti and Nb has good capability of resisting atmosphere and seawater corrosion; the addition of V, Ti and Nb has obvious intergranular corrosion resistance; and the addition of Cr, Nb, V, Ti, Si and RE makes the alloy steel have … … very obvious high temperature oxidation resistance.
The low-alloy cast steel with high strength, impact resistance, heat resistance and low temperature resistance is smelted by adopting an electric arc furnace; slagging by using lime powder and fluoride powder in a ratio of 2: 1; the steelmaking raw materials are scrap steel and ferroalloy; the charging sequence is as follows: scrap steel, ferrochromium; adding ferromanganese and ferromolybdenum after melting and deslagging; adding Si in the reduction period, and carrying out primary deoxidation by using Mn and Si; adding ferrovanadium, ferroniobium and FeN (chromium nitride) after deslagging, sequentially adding Zr and Ti and then adding Rare Earth (RE) at an interval of 5-10 minutes after deslagging again; adding 1KG of amphoteric oxide aluminum (A1) into each ton of molten steel before casting for final deoxidation treatment, wherein the tapping temperature is as follows: 1620-1580 deg.c, and casting at 1570-1480 deg.c. The specific production process comprises the following steps:
1. casting of a blank: the tapping temperature is 1620-1580 ℃, the casting temperature is 1570-1480 ℃, the casting is unpacked at 250-300 ℃, and the temperature of a cutting casting head is not less than 230 ℃;
2. annealing treatment: heating the cleaned and finished blank in a furnace to 650-720 ℃, preserving heat for 8-12 hours, cooling the blank in the furnace to be less than or equal to 350 ℃, discharging the blank out of the furnace, and air cooling the blank;
3. and (3) machining:
(1) scribing and rough machining: hanging the annealed blank on a platform, aligning the annealed blank according to the center line of the workpiece vertical to the platform, and marking out according to the condition that 2.5mm-3.0mm is left on one side; aligning and clamping the scribed blank according to a line, and then performing rough machining, wherein the outline is subjected to 100% over-detection;
(2) quenching, tempering and finishing: heating the semi-finished product qualified by the super probe integrally in a furnace to 880-960 ℃, preserving heat for 3-5 hours, and then uniformly cooling; then the temperature is raised to 530-700 ℃, the temperature is kept for 2-4 hours and the mixture is cooled, and then the mixture is processed and formed according to the size of the drawing.
Compared with the Germany with developed materials in the world, the high-strength low-alloy cast steel with the characteristics of impact resistance, heat resistance and low temperature resistance has the advantages that the yield strength (bps) is improved by 12.07 percent, and the impact toughness (alpha ku) is improved by 47.73 percent; and to russia: the yield Strength (BBs) is improved by 33.42%, and the impact toughness is improved by 10.17%; compared with the traditional ZG35SiMn, the yield strength (bams) is improved by 86.8 percent, the impact toughness is improved by 85.7 percent, and the strength is improved by 20.7 percent. The method fundamentally, comprehensively and thoroughly solves the economic and technical problems of easy fracture, low strength, no wear resistance, short service life, frequent replacement, high manufacturing or using cost of various alloy cast iron or cast steel materials and most forged steel quenched and tempered products which exist for a long time under the conditions of heavy load and strong wear or impact in the industries of petrifaction, mine, metallurgy, building materials, electric power, machinery, ordnance and the like in which the working temperature is lower than or equal to (+500 ℃) or the working temperature is lower than or equal to minus 50 ℃) and the heat is lower than or equal to 500 ℃ at the same time.
According to the product price of advanced Germany and American [ (12-16) ten thousand yuan/ton ], the price is reduced according to the lowest price (12 ten thousand yuan/T): 24000 dollar/T) is reduced by 45% more (i.e.: 6.6 ten thousand yuan/T) if 1.5 ten thousand tons are exported every year, the export can be $ 1.523 million per year in the country; according to the industry of finished project products and products of the owner of the invention, the annual market consumption of China is at least 2000 ten thousand tons, and if the owner of the invention relies on import, the foreign exchange expenditure of China can reach: 2000 kiloton × 2.4 ten thousand yuan/T (U $) 4800 million yuan.
Therefore, the steel has wide practical value and popularization value, thereby obtaining remarkable enterprise benefit and huge social and comprehensive economic benefit.
Detailed Description
The steel of the invention was now used in the fourth embodiment of the present invention for the production of cast steel end plates (net weight: 985 kg/piece) in large hammer mills [ main dimensions: corresponding detection size data (mm) and process execution temperatures of Φ 1650 (outer diameter) × 55 (thickness) × 6 of circular bosses with edge planes [ [ Φ 280 (outer diameter) × Φ 143 (aperture) × 32 (height) ] × Φ 650 (middle circular truncated cone) × 420 × 420 (square hole) ] are respectively listed as follows:
the four-furnace steel furnace comprises the following chemical components:
the process temperature and the detection performance of the four-furnace cast steel production process [ unit: degree centigrade (T deg.C) ]
The specific implementation process is as follows: according to the steel composition of the invention, four furnaces (2 pieces/furnace) are smelted by adopting a 2 ton electric arc furnace (3.5 ton molten steel/furnace), and the tapping temperatures are respectively as follows: 1590 deg.C, 1610 deg.C, 1580 deg.C, 1620 deg.C; the casting temperature corresponds to: 1560 deg.C, 1570 deg.C, 1500 deg.C, 1480 deg.C; the opening temperature of the end plate cast steel blank is correspondingly as follows: cutting a casting head at 250 ℃, 300 ℃, 280 ℃ and 270 ℃ with the temperature T ℃ being more than or equal to 220 ℃ and grinding; each furnace cast steel blank is respectively as follows: 680 ℃, 650 ℃, 690 ℃ and 720 ℃, and the heat preservation time is as follows: t is 8 hours, and the steel is taken out of the furnace and cooled in air after being cooled to 200 ℃; and then, carrying out numerical control rough turning according to the size of the graph and the single side of 3 mm. The heating temperature of the rear special furnaces is correspondingly as follows: 880 deg.C, 900 deg.C, 930 deg.C, 960 deg.C; corresponding heat preservation time: cooling uniformly after 4 hours; tempering at 550 ℃, 630 ℃, 680 ℃ and 700 ℃ respectively, and preserving the heat for: all cool 2.5 hours later, carried out performance detection and metallographic analysis to the same stove test piece one by one simultaneously, the detection unit mainly has: the Wuhan metal material test detection center of the general company of the Zhonghai, the Wuhan iron and steel design research institute, and the like; the using effect of the product is satisfied by each user.
Claims (2)
1. The high-strength impact-resistant heat-resistant low-temperature-resistant alloy steel is characterized by comprising the following chemical components in percentage by weight:
C：0.26-0.42；Si：0.40-0.75；Mn：0.65-1.25；Cr：0.9-1.4；
Mo：0.5-0.85；V：0.30-0.65；Nb：0.2-0.42；N≤0.15；Ti≤0.18；
zr is less than or equal to 0.18; RE is less than or equal to 0.18; p is less than or equal to 0.02; s is less than or equal to 0.02; fe: 96.06-93.53, and at least one of the four elements of N, Ti, Zr and RE in the above-mentioned components is not zero, and the rest is Fe.
2. A process for manufacturing a high strength impact heat and low temperature resistant alloy steel for carrying out the method of claim 1, comprising the steps of:
(1) casting of a blank: the tapping temperature is 1620-1580 ℃, the casting temperature is 1570-1480 ℃, the casting is unpacked at 250-300 ℃ for sand removal, and the casting temperature of the cutting casting head is not less than 230 ℃.
(2) Annealing treatment: heating the cleaned and integrated blank in a furnace to 650-720 ℃, preserving heat for 8-12 hours, cooling the blank in the furnace to be less than or equal to 350 ℃, taking the blank out of the furnace, and air cooling the blank;
(3) and (3) machining:
scribing and rough machining: hanging the annealed blank on a platform, aligning the center line of the workpiece perpendicular to the platform, and marking by reserving 2.5-3 mm on one side of the machined surface as required; aligning and flattening the blank which is already subjected to line drawing according to the line, and then performing rough machining;
secondly, quenching, tempering and finish machining: heating the semi-finished product qualified by the super probe in a furnace to 880-960 ℃, preserving heat for 3-5 hours, then uniformly cooling, reheating to 530-700 ℃, and preserving heat for 2-4 hours, and uniformly cooling; and hoisting the qualified semi-finished product after hardening and tempering to finish machining equipment, aligning, clamping, and performing finish machining and forming according to the requirements of a drawing.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116536570A (en) * | 2023-05-21 | 2023-08-04 | 襄阳金耐特机械股份有限公司 | G26CrMo4 cast steel without casting crack and application thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61143523A (en) * | 1984-12-17 | 1986-07-01 | Toshiba Corp | Manufacture of rotor for geothermal energy turbine |
| JP2000026937A (en) * | 1998-07-09 | 2000-01-25 | Kawasaki Steel Corp | High strength pc steel bar and its production |
| CN1740367A (en) * | 2005-09-14 | 2006-03-01 | 刘承刚 | High strength heat resistant antiwear vertical mill sheath and its making process |
| CN102312159A (en) * | 2010-07-06 | 2012-01-11 | 泰州汇能不锈钢制品有限公司 | Heat treatment process of martensite wear-resistant cast steel |
| CN103266276A (en) * | 2013-02-03 | 2013-08-28 | 王康 | Method for preparing low alloy high wear resistant cast steel plate |
| CN107177797A (en) * | 2017-04-24 | 2017-09-19 | 江阴兴澄特种钢铁有限公司 | The oil gas field anti-corrosion drilling tool steel of 130KSI, 135KSI rank and its manufacture method |
| CN110129675A (en) * | 2019-05-23 | 2019-08-16 | 江苏省沙钢钢铁研究院有限公司 | High tensile reinforcement and its production method |
-
2019
- 2019-11-26 CN CN201911175009.5A patent/CN112941420B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61143523A (en) * | 1984-12-17 | 1986-07-01 | Toshiba Corp | Manufacture of rotor for geothermal energy turbine |
| JP2000026937A (en) * | 1998-07-09 | 2000-01-25 | Kawasaki Steel Corp | High strength pc steel bar and its production |
| CN1740367A (en) * | 2005-09-14 | 2006-03-01 | 刘承刚 | High strength heat resistant antiwear vertical mill sheath and its making process |
| CN102312159A (en) * | 2010-07-06 | 2012-01-11 | 泰州汇能不锈钢制品有限公司 | Heat treatment process of martensite wear-resistant cast steel |
| CN103266276A (en) * | 2013-02-03 | 2013-08-28 | 王康 | Method for preparing low alloy high wear resistant cast steel plate |
| CN107177797A (en) * | 2017-04-24 | 2017-09-19 | 江阴兴澄特种钢铁有限公司 | The oil gas field anti-corrosion drilling tool steel of 130KSI, 135KSI rank and its manufacture method |
| CN110129675A (en) * | 2019-05-23 | 2019-08-16 | 江苏省沙钢钢铁研究院有限公司 | High tensile reinforcement and its production method |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116536570A (en) * | 2023-05-21 | 2023-08-04 | 襄阳金耐特机械股份有限公司 | G26CrMo4 cast steel without casting crack and application thereof |
| CN116536570B (en) * | 2023-05-21 | 2024-04-12 | 襄阳金耐特机械股份有限公司 | G26CrMo4 cast steel without casting crack and application thereof |
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