120results about How to "Guaranteed hardenability" patented technology

The invention discloses a disk-shaped roller cutter ring with high hardness, good toughness and excellent comprehensive performance. The disk-shaped roller cutter ring comprises the following ingredients of: 0.46-0.56% of C, 0.80-1.20% of Si, 0.20-0.65% of Mn, 5.00-5.80% of Cr, 1.15%-1.55% of Mo, 0.85-1.40% of V and the balance Fe and impurities, wherein the content of P is no more than 0.02%, and the content of S is no more than 0.01%; and the overall hardness of the cutter ring is HRC55-61 (Rockwell Hardness C55-61), or the hardness is of graded distribution, i.e. the hardness of a working edge area is HRC55-61, the hardness of a transition surface area is HRC50-57, and the hardness of a step assembly surface area and an inner ring is HRC44-51. A preparation method of the disk-shaped roller cutter ring comprises the following steps of: smelting the raw materials in an electric furnace; carrying out electroslag remelting; preforging; carrying out die forging; carrying out slow cooling; annealing; carrying out rough machining to obtain a disk-shaped roller cutter ring rough blank; carrying out high-temperature vacuum hardening and two-time high-temperature tempering on the cutter ring rough blank; carrying out low-temperature destressing treatment; carrying out fine finishing to obtain the cutter ring with the overall hardness of HRC55-61, wherein the cutter ring with the overall hardness of HRC55-61 is applicable to the tunneling of a hard rock formation by a shield tunneling machine; or carrying out medium-frequency induction tempering treatment prior to the low-temperature destressing treatment to obtain the cutter ring with graded-distribution hardness, wherein the cutter ring with the graded-distribution hardness is applicable to the tunneling of a rock formation with an upper soft part and a lower hard part.

The invention discloses an economical non-quenched and non-tempered micro-alloyed plastic die steel plate and a making method thereof. The economical non-quenched and non-tempered micro-alloyed plastic die steel plate comprises 0.32-0.40wt% of C, 0.20-0.50wt% of Si, 1.00-1.50wt% of Mn, 1.20-1.70wt% of Cr, 0.20wt% or less of Mo, 0.0025wt% or less of B, 0.03wt% or less of Ti, 0.03wt% or less of Nb, and the balance Fe. The making method comprises the following steps: carrying out converter smelting, LF+RH refining and continuous slab casting; heating the obtained slab at 1200-1230DEG C, carrying out precision rolling at 900-950DEG C, and carrying out finishing rolling at 870-920DEG C; carrying out controlled cooling after the steel plate rolling; and tempering the steel plate obtained after the controlled rolling and controlled cooling at 550-600DEG C to obtain the finished pre-hardened plastic die steel plate having a bainite structure. The yield strength, the normal temperature impact toughness and the cross section hardness of the steel plate are above 800MPa, above 20J and 310-350HB respectively. The making method is suitable for the production of pre-hardened plastic die steel plates with the specification of below 120mm from 320mm continuous casting blanks.

The present invention relates to one kind of cast steel for bearing parts in mechanical lifting system and its making process. The cast steel of Cr-Ni-Mo line consists of C 0.15-0.30 wt%, Mn 0.60-1.10 wt%, Si 0.3-0.8 wt%, Ni 0.4-1.1 wt%, Cr 0.4-1.1 wt%, Mo 0.15-0.40 wt%, S less than 0.025 wt%, P less than 0.025 wt%, and residual elements including Cu, W and V less than 0.60 wt%. The making process of the cast steel includes the following technological steps: making steel in MF furnace or electric arc furnace; casting in sand mold with equivalent circular kiel test rod; normalizing, quenching and tempering of both cast part and test rod in the same furnace; and non-destructive detection of the cast part.

The invention relates to steel for a low-carbon wear-resistant engineering machinery creeper tread and a manufacturing method thereof. The steel comprises the following chemical components in percentage by weight: 0.17-0.27 percent of C, 0.17-0.37 percent of Si, 0.85-1.20 percent of Mn, 0.10-0.30 percent of Cr, 0.010-0.060 percent of Al, 0.010-0.20 percent of Cu, 0.01-0.20 percent of Ni, 0.003-0.025 percent of P, 0.001-0.025 percent of S, 0.020-0.060 percent of Ti, 0.0005-0.0035 percent of B, 5-20*10<-6> percent of [O], 40-90*10<-6> percent of [N] and the balance of Fe and inevitable impurities. The manufacturing method adopts an electric furnace for smelting and making steel, an LF furnace for external refining and VD for vacuum degassing treatment. The steel and the manufacturing methodhave excellent technical effects.

The invention provides high-performance ocean platform steel and its production method. When the thickness of a steel plate is 8-40mm, the steel plate is composed of the following chemical components, by weight, 0.11-0.13% of C, 0.20-0.50% of Si, 1.45-1.55% of Mn, 0.012% or less of P, 0.003% or less of S, 0.035-0.045% of V, 0.025-0.030% of Nb, 0.050% or less of Ti, 0.020-0.050% of Al, and the balance Fe and inevitable impurities; and when thickness of a steel plate is 40-100mm, the steel plate is composed of the following chemical components, by weight, 0.10-0.12% of C, 0.20-0.50% of Si, 1.50-1.60% of Mn, 0.012% or less of P, 0.003% or less of S, 0.070-0.075% of V, 0.030-0.040% of Nb, 0.050% or less of Ti, 0.020-0.050% of Al, and the balance Fe and inevitable impurities. The production method of the steel plate of the invention comprises the steps of electric furnace smelting, LF furnace refining, VD vacuum treatment, continuous casting (or die casting), heating, control rolling, cooling, stacking, and normalizing to prepare the steel plate. Through a reasonable component design and process optimization, the steel plate of the invention has excellent mechanical performances, welding performances and processing performances, and has strong market competitiveness.

The invention provides a double-phase steel plate which comprises 0.07-0.098 of C, 0.1-0.4 of Si, 1.95-2.2 of Mn, 0.3-0.6 of Cr, less than or equal to 0.015 of P, less than or equal to 0.004 of S, less than or equal to 0.005 of N, 0.015-0.04 of Nb, 0.015-0.04 of Ti, 0.015-0.045 of Al, and 0.002-0.004 of B or 0.2-0.4 or Mo, wherein Pcm equals to C+Si / 30+Mn / 20+2P+4S which is less than or equals to 0.24; and the double-phase steel plate also comprises the balance of Fe and unavoidable impurities. The invention also provides a manufacturing method of the double-phase steel plate. The high-strength uniform-performance double-phase steel plate can be obtained by the proper composition design and manufacturing technology, and the manufacturing requirements on parts of a high-strength automobile body can be better met.

The invention relates to a kind of cold-rolled hot-galvanized complex phase steel. Chemical components of the cold-rolled hot-galvanized complex phase steel comprise, by weight, 0.05-0.13% of C, 0.1-0.5% of Si, 1.5-2.5% of Mn, less than or equal to 0.015% of P, less than or equal to 0.015% of S, 0.1-0.6% of Al, 0.2-0.6% of Cr, 0.1-0.5% of Mo, 0.01-0.06% of Nb, 0.01-0.06% of Ti, and the balance Feand inevitable impurities. The invention further relates to a preparation method of the cold-rolled hot-galvanized complex phase steel. The preparation method comprises the following steps of castingmolten steel into a steel billet; conducting hot rolling on the steel billet to obtain a hot-rolled plate and conducting cold rolling on the hot-rolled plate to obtain a cold-hardened steel strip; conducting continuous galvanizing and annealing process treatment on the cold-hardened steel strip to obtain a finished cold-rolled hot-galvanized complex phase steel product. The bending performance ofthe cold-rolled hot-galvanized complex phase steel is improved on the basis of meeting the requirement for strength.

The invention provides a steel material for thermal punching formation, a thermal punching formation process and a thermal punching formation component. The steel material contains the following components in percentage by weight: 0.2%-0.4% of C, 0-0.8% of Si, 0-1.0% of Al, 0-0.005% of B, 0.5%-3.0% of Mn, 0-1% of Mo, 0-2% of Cr, 0-5% of Ni, 0-0.4% of V, 0-0.2% of Nb, Ti less than or equal to 0.01%and the balance of following unavoidable impurity elements such as P, S and N during smelting, wherein when B is less than or equal to 0.0005%, a formula 29*Mo+16*Mn+14*Cr+5.3*Ni is more than or equal to 30%; and when B is more than 0.0005% and less than or equal to 0.005%, the steel material contains 0.4%-1.0% of Al.

The invention discloses a high-grade wear-resistant steel plate. The steel plate comprises the following components in percentage by mass: less than or equal to 0.26 percent of C, less than or equal to 0.50 percent of Si, less than or equal to 1.60 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.005 percent of S, 0.10 to 0.30 percent of Ni, less than or equal to 1.50 percent of Cr, less than or equal to 0.06 percent of Nb, 0.02 to 0.06 percent of Al, less than or equal to 0.03 percent of Ti, less than or equal to 0.50 percent of Mo, less than or equal to 0.08 percent of V, less than or equal to 0.004 percent of B, and the balance of Fe and inevitable impurities. A method for producing the steel plate comprises smelting, casting, heating, rolling, straightening, shot blasting, quenching, heat treatment, cutting and other process steps. The steel plate has the advantages of steel purity, high strength, high hardness, good low temperature toughness, good weldability, good processability, good cold bending property, large steel plate thickness, good plate cut, little noble metal added to the steel plate and low cost. The steel plate can be widely used in the industry of manufacturing mining, engineering, metallurgical and other machinery with broad application prospects.

The invention relates to extra-thick tempering EH40 steel for ocean engineering. A steel plate comprises the following chemical components by weight percent: 0.12 to 0.15 percent of C, 0.15 to 0.50 percent of Si, 1.30 to 1.60 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.0050 percent of S, 0.020 to 0.050 percent of Nb, 0.020 to 0.050 percent of V, 0.008 to 0.020 percent of Ti, 0.15 to 0.40 percent of Ni, 0.10 to 0.20 percent of Cr, and balance of Fe and unavoidable impurity elements. The manufacturing process of the steel plate comprises the steps of smelting, casting, reheating, rolling and tempering. The tempering process is used for substituting the normalizing process to produce a low-scaling-ratio extra-thick plate, so that the adverse effect caused by the center segregation can be avoided.

The invention relates to a 135 steel-level drill rod connector and a heat treatment process thereof. The drill rod connector comprises the following components in percentage by weight: 0.25-0.32 percent of C, 0.30 percent of or less Si, 0.35-0.80 percent of Mn, 0.015 percent of or less P, 0.008 percent of or less S, 0.15-0.80 percent of Mo, 0.00-1.00 percent of Ni, 0.90-1.50 percent of Cr, 0.30 percent of or less Al, 0.05 percent of or less Nb, 0.10 percent of or less V and the balance of Fe and unavoidable trace elements. The heat treatment process comprises the steps of: heating a roughly processed connector blank to 920-960 DEG C from the room temperature, preserving heat for 0.5-1.5 hours, putting the connector blank into a high-grade oil base quenching medium at 30-50 DEG C, fully cooling the connector blank, then heating the connector blank to 550- 620 DEG C from the room temperature for 50-70 minutes, preserving heat for 1.5-2.5 hours, and then discharging the connector. After heat treatment, the mechanical performances are as follows: the yield strength is 140-160 Ksi (965-1100 MPa), the elongation percentage is larger than or equal to 17 percent, the drill rod connector is longitudinal and is at 20 DEG C below zero and has full size, and the charpy impact energy is higher than or equal to 100 Joules.

The present invention relates to a high-performance hydrogen sulfide corrosion resistant petroleum drill pipe with a weight percentage of components as follows: C 0.20-0.32 percent, Si 0.1-0.5 percent, Mn 1.0-1.5 percent, Cr 0.5-1.5 percent, Mo 0.8-1.2 percent, P less than or equal to 0.015 percent, S less than or equal to 0.01 percent and the remainders are Fe and unavoidable impurities. The drill pipe of the present invention has a higher content of Mn, which can guarantee an upset end with a thickness of over 30mms to be fully hardened, thereby guaranteeing the sulfur-resistant performance of the upset end. The drill pipe of the present invention has a higher content of Mo, which can improve the backfire-preventive stability of the material, thereby raising the backfire temperature, reducing the residual stress and guaranteeing the sulfur-resistant performance. Simultaneously, the invention can make the pipe body with a different wall thickness and the upset end have the same cooling speed by controlling the outer water injection of the upset end and pipe body of the steel pipe, reducing the water injection outside the pipe body or increasing the water injection outside the upset end of the drill pipe, to ensure that the pipe body and the upset end have the same quenching structure, and the same mechanical property can be achieved after the backfire.

A production method of a boracic non-hardened and tempered plastic die steel belongs to the technical field of medium steel plate production. The process is that a continuous casting billet is soaked at the temperature of 1150-1250 DEG C; the hot rolling temperature is controlled, the start rolling temperature of the finish rolling is 900-950 DEG C, and the finishing rolling temperature is 840-880 DEG C; the steel plate is in controlled cooling after the hot rolling, and the cooling speed is controlled at 1-5 DEG C per second; and tempering treatment is required after rolling. The methods of controlled rolling and controlled cooling are adopted to obtain the 20-80mm bainite structure steel plate, stress relief tempering is carried out after rolling, and the combination property of the steel plate meets the process requirements of P20 pre-hardened steel. The yield strength of the steel plate is not less than 650MPa, the tensile strength is not less than 900MPa, the hardness of the cross section is 280-330HV, and the polishing property meets the requirements of P20 pre-hardened steel plates.

The invention relates to a multi-stage spray quenching process for achieving the low residual stress of an age hardening aluminum alloy. The material of the age hardening aluminum alloy is thermally insulated at the solution temperature, three stages of cooling with different surface cooling speeds are sequentially and continuously conducted, a first-stage surface cooling speed is at least up to 40 DEG C / s, a second-stage surface cooling speed is 10-20 DEG C / s, and a third-stage cooling is naturally cooled in the air to the room temperature. The first-stage cooling and the second-stage cooling adopt spray cooling, and the cooling medium is water. Compared with a single-stage spray quenching method, the multi-stage spray quenching effectively reduces the quenching residual stress on the premise of guaranteeing that the core of the material is quenched through. The process provided by the invention is simple in method and convenient in operation, the quenching degree and the lower quenching residual stress of the age hardening aluminum alloy are guaranteed, and the process is suitable for industrial production and is of great significance for the production of age hardening aluminum low-residual-stress boards, sectional materials and forge pieces.

The invention relates to an armor steel plate with a high anti-bullet property and a manufacturing method of the armor steel plate. The armor steel plate comprises chemical components in percentage by weight as follows: 0.20%-0.28% of carbon, smaller than or equal to 0.10% of silicon, 0.20%-0.50% of manganese, smaller than or equal to 0.012% of phosphorus, smaller than or equal to 0.003% of sulfur, 0.90%-1.30% of chromium, 0.20%-0.40% of molybdenum, 0.015%-0.035% of titanium, 0.020%-0.050% of aluminum, smaller than or equal to 0.00020% of hydrogen, smaller than or equal to 0.0040% of nitrogen, smaller than or equal to 0.65% of carbon equivalent and the balance of iron and inevitable impurities. The hardness of armor steel with the high anti-bullet property reaches 480-550 HBW, the shock absorption energy at the temperature of subzero 40 DEG C is larger than or equal to 20 J, and the armor steel plate has penetration resistance, can prevent armor steel from cracking, breaking or stripping and has the characteristics of low cost, stable quality, simplified process and easiness in large-scale industrial production.

The invention relates to steel for caterpillar type engineering machinery caterpillar link pin bushes and a production method thereof, which belong to the technical field of metallurgy. The steel for the caterpillar type engineering machinery caterpillar link pin bushes consists of the following chemical components in percentage by weight: 0.38 to 0.43 percent of C, 0.10 to 0.25 percent of Si, 0.60 to 0.85 percent of Mn, 0.90 to 1.20 percent of Cr, 0.30 percent or less than 0.30 percent of Cu, 0.025 percent or less than 0.025 percent of S, 0.030 percent or less than 0.030 percent of P, 0.20 percent or less than 0.20 percent of Ni, 0.001 to 0.004 percent of B, 0.030 to 0.050 percent of Ti, 0.015 to 0.060 percent of Al, 15*10< -6 > percent or less than 15*10< -6 > percent of O, 3*10 <-6 > percent or less than 3*10 <-6 > percent of H, 60*10 <- 6> percent or less than 60*10 <- 6> percent of N and the balance Fe and inevitable impurities. The invention also provides the production method for the steel for the caterpillar type engineering machinery caterpillar link pin bushes, and the production method can be adopted to produce round steel with the specification of 30mm to 100mm in diameter. The steel has high fatigue resistance, wear resistance and corrosion resistance, the performance of a machined caterpillar type engineering machinery caterpillar link pin bush is excellent, and the service life of the caterpillar type engineering machinery caterpillar link pin bush made of the steel is longer than the service life of the caterpillar type engineering machinery caterpillar link pin bush made of an ordinary alloy structure steel material.

This invention relates to a MnCu alloy ADI car rear axle screw bevel gear and its preparation method, which takes ordinary pig iron as the raw material of said gear, applies a duplex method of cupola and electric cooker, takes rear earth, Mg and silicon iron alloy as the nodulizer to be processed then to slag and eliminate slag, gestates and casts the gear roughcast in two times, then finishes it after mechanical process, isothermal quenching and temper, in which, the composed weight percentage of said gear is: C 3.4-3.8%, Si 2.4-2.9%, Mn 0.4-1.0%, Cu 0.5-1.2%, P less than 0.06%, S less than 0.02% and the rest is iron.

The invention discloses a non-annealed cold forging steel hot-rolled wire rod and a production method thereof. The method comprises the steps of continuous casting, heating, rolling, spinning and cooling. The non-annealed cold forging steel hot-rolled wire rod comprises 0.29-0.38wt% of C, 0.15-0.30wt% of Si, 0.70-0.90wt% of Mn, 0.03wt% or less of P, 0.03wt% or less of S, 0.30wt% or less of Cr, 0.0008-0.0050wt% of B, and the balance of Fe and residual elements. In the heating step, continuous cast billets are heated to 1100-1190DEG C; in the rolling step, the initial finish rolling temperature is 965-995DEG C; in the spinning step, the spinning temperature is 960-990DEG C; and in the cooling step, the cooling speed is 0.5-1.5DEG C / s. The method realizes production of the non-annealed cold forging steel hot-rolled wire rod through optimally designing chemical components, controlling the heating temperature, the initial finish rolling temperature, the spinning temperature and the cooling speed and controlling the amount and the grain size of ferrite by using present devices and technologies without increasing investment or production cost, so the non-annealing production and cost reduction demands of downstream users are met, and pollution of annealing to environment is avoided.

The invention discloses an intermediate-carbon high-speed cutting saw blade matrix steel and a production method thereof. The steel comprises the following components in percentage by weight: 0.20-0.40% of C, 0.10-0.30% of Si, 0.45-0.63% of Mn, not more than 0.010% of P, not more than 0.005% of S, 0.008-0.020% of Ti, 0.80-1.20% of Cr, not more than 0.005% of N, 0.020-0.050% of Al, 0.10-0.20% of Ni, 0.030-0.050% of V and the balance of Fe and inevitable impurities, wherein Als / N is not less than 30%, Mn +Cr is 1.45-1.85. The production method comprises the following steps of: desulfurizing molten iron, smelting in a converter, carrying out vacuum treatment, casting continuously, hot-rolling continuously, cooling, coiling, leveling, quenching and tempering. Facts prove that the steel has pure steel quality, strong toughness, high wearing resistance and low cost at the same time. The production method of the steel is simple in process and stable in product property.

The invention discloses a steel tube used for a hollow stabilizer bar of an automobile and a manufacturing method of the steel tube. The steel tube is prepared from the following chemical components in mass percent: 0.28 to 0.40 percent of C, 0.05 to 0.35 percent of Si, 1.05 to 1.60 percent of Mn, 0.1 to 0.6 percent of Mo, 0.001 to 0.006 percent of B, 0.015 to 0.060 percent of Al, 0.1 to 0.8 percent of Cr, 0.003 to 0.06 percent of Ti, not greater than 0.006 percent of S, not greater than 0.015 percent of P, not greater than 0.003 percent of O and the balance Fe and other inevitable impurities,wherein Mo+50B+Cr is not less than 0.7 percent but is not greater than 1.3 percent. The steel tube disclosed by the invention is high in strength and plasticity, has high torsion fatigue resistance under a relatively high stress level, and can meet the using requirement of the stabilizer bar under a high-stress condition; and the specific performance indexes are shown as follows: as-quenched tensile strength is not less than 1700 MPa, as-quenched yield strength is not less than 1300 MPa, as-quenched ductility is not less than 12 percent, inner surface decarburization depth and outer surface decarburization depth are both 0, and under the condition of 550 MPa, the number of times of torsion fatigue is greater than 1200000.

The invention relates to a low-cost manufacturing method for a high-intensity quenched and tempered steel plate and belongs to the technical field of metallurgy. Ingredient design of the manufacturing method is based on a traditional quenched and tempered high-intensity steel plate, valuable alloy elements such as Ni, Mo, Cu, Nb and V are not required, the valuable alloying elements are greatly saved, alloy cost is greatly reduced, the cost advantage is remarkably improved, and the economic benefit is obvious. The ingredient design can be combined with four different tempering processes to respectively produce products meeting the performance requirements of 6-60mm and 600-800MPa intensity-level high-intensity steel. A process window is wide, process adaptability is wide, and one-steel multi-stage flexible manufacturing is achieved.

The invention discloses a high-manganese pre-hardened plastic die steel plate and a production method thereof. The steel plate comprises the following chemical components in percentage by mass: 0.32-0.40% of C, 1.30-1.80% of Mn, 0.30-0.60% of Si, S smaller than or equal to 0.015%, P smaller than or equal to 0.020%, 1.40-2.00% of Cr, 0.30-0.50% of Mo, 0.015-0.040% of Al and the balance of Fe and inevitable impurities. The production method comprises the steps of converter smelting, LF (Ladle Furnace) refining, RH (Ruhrstahl Hereaeus) vacuum refining, continuous casting sheet billet, controlled rolling and cooling and tempering. The steel plate disclosed by the invention has the advantages that the production cost is effectively reduced through the chemical component design of high manganese; and pre-hardened plastic die steel with the hardness of 28-38HRC is obtained by adopting the steps of the controlled rolling and cooling and the high-temperature tempering heat treatment. The method has the characteristics that the chemical component design is reasonable; the product performance is excellent; and the process is simple.

The invention discloses a quenching pressing die fixture which comprises a fixed tray, base plates, inner pressing rings and outer pressing rings, wherein conical holes with large lower parts and small upper parts are formed in the lower ends of the outer pressing rings; radial step holes are formed in the base plates; a screw is connected to each step hole; a supporting ring is arranged on each screw in a sliding manner; outer resetting springs are sleeved on the screws; conical surfaces with large lower parts and small upper parts are arranged on the outer walls of the supporting rings; a plurality of axial slots and a plurality of radial slots are formed in the inner walls of the supporting rings; a center hole and convex rings are arranged on the fixed tray; an expanding mandrel penetrates through the center hole and is provided with a cone with a large upper part and a small lower part; a plurality of expanding blocks are arranged around the cone on the fixed tray in a sliding manner; a conical surface matched with the cone is arranged on the inner wall of each expanding block; a plurality of axial slots and a plurality of radial slots are formed in the outer wall of each expanding block; each expanding block is provided with a radial step hole; a connection screw is connected with each step hole; inner resetting springs positioned between the convex rings and the corresponding expanding blocks are sleeved on the connection screws. The quenching pressing die fixture can effectively control the deformation of a workpiece in various directions and guarantee the hardenability, so that the yield of a product is greatly improved.

The invention discloses a high-toughness spring steel and a preparation method thereof. The spring steel comprises the following alloy components by weight percent: 0.27-0.32% of C, less than or equal to 0.30% of Si, 0.80-1.20% of Mn, 0.30-0.50% of Cr, less than or equal to 0.25% of Ni, less than or equal to 0.30% of Cu, less than or equal to 0.035% of S, less than or equal to 0.035% of P, the balance of Fe, and inevitable impurities, and the alloy component of the spring steel also comprises B being less than or equal to 0.0035%. The preparation method comprises the following steps of a. collecting, screening and sorting waste steel; b. proportioning materials and feeding the materials into a furnace according to component requirement of the primary refining of the type of the steel; c. smelting in an intermediate frequency furnace; d. melting down, slagging off and sampling; e. alloying through partial deoxygenation in the intermediate frequency furnace; f. slag-free tapping; g. deoxidizing in a ladle, and manufacturing ladle refining slag; h. refining in a finery; i. staying the ladle and soft blowing; j. pouring molten steel under the full protection of a conticaster; k. collecting the finished product; l. pile cooling, and slowly cooling for 24 hours; and m. coating color codes of the type of the steel. The high-toughness spring steel has better toughness and hardenability, the lower limit carbon content is improved to 0.27% so that the hardenability of the steel is guaranteed, and the property of a leaf spring is guaranteed.

The invention discloses a surface treatment method for solid carbon-boron complex penetration of a low-carbon alloy steel part. The method at least comprises the steps of: (a) carburizing pretreatment and steel part cleaning; (b) carburizing treatment; (c) taking out of a penetration box for carburizing from a resistance furnace, natural cooling to a room temperature, and taking out of a low-carbon alloy steel part after the carburizing treatment; (d) boriding pretreatment and steel part cleaning; (e) boriding treatment; (f) taking out of a penetration box for boriding from the resistance furnace after the boriding treatment in the step (e), natural cooling to the room temperature, and taking out of a low-carbon alloy steel part after the boriding treatment; (g) quenching treatment; and (h) tempering treatment. The method has the following beneficial effects: the carburizing and the boriding are performed in sequence to form a transition layer on the surface of the low-carbon alloy steel, so that a boriding layer and a steel basal body are better in combination and not easy to drop.

The invention discloses high-speed tool steel for drill bits, which comprises the following components: 0.90-0.98% of C; 5.00-5.80% of W; 4.00-4.60% of Mo; 3,80-5.00% of Cr; 1.80-2.20% of V; 0.25-0.45% of Mn; 0.2-0.40% of Si; 0.08-0.30% of Nb; 1.30-1.60% of Co; not more than 0.03% of P; not more than 0.03% of S; and the balance of Fe. According to the invention, the using amounts of precious metal tungsten and molybdenum are reduced; a little niobium is added; the steel is provided with good application performance and processing performance; and prepared cutters have increased service life.

The invention provides a manufacturing method of a seamless steel pipe for a long pipe trailer gas cylinder with a diameter of 920mm, and belongs to the manufacturing technology of large diameter seamless steel pipes. The manufacturing method comprises the steps that the chemical composition of seamless steel pipe materials is optimized, and the hardenability of the composition is improved; afterusing a 820 cross rolling mill to pierce, a waste pipe is rolled, a jacking type hot expanding unit is used for expanding the diameter, a hydraulic type straightening machine and a six-roll straightening machine are used for two-step straightening and rounding, and a precision cold drawing unit is used for two cold pullout. According to the manufacturing method of the seamless steel pipe for the long pipe trailer gas cylinder with the diameter of 920mm, the manufacturing cost is low, the material utilization rate is high, and the mode of production is flexible; and moreover, the phi 920mm seamless steel pipe manufactured by the method has high geometric accuracy, good internal and external surface quality, good hardenability and high comprehensive performance, and the range of the actual weight of a finished product exceeding the theoretical weight does not exceed 7.5%.

The invention discloses steel for a large-sized wind power fastener. The steel is prepared from the element components in percentage by mass: 0.38-0.45% of C, 0.20-0.35% of Si, 0.60-0.80% of Mn, lessthan or equal to 0.015% of P, less than or equal to 0.010% of S, 0.95-1.20% of Cr, 0.18-0.30% of Mo, 0.10-0.25% of Ni, 0.02-0.08% of Nb, 0.020-0.050% of Al, less than or equal to 0.008% of N, and thebalance of Fe and inevitable impurities. After heat treatment, the core part of the steel is provided with 90% or above of a martensitic structure, the surface hardness difference of the core part isless, especially the low-temperature impact property is excellent, the good mechanical properties are achieved, the tensile property meets the 10.9-grade strength requirements, and the machining usingrequirements for the steel for 48-65 mm of the large-sized wind power fastener by a user can be met.

The invention belongs to the technical field of hot working of section-variable aluminum alloy die forgings, and in particular relates to a hot working method for improving the structure and the performance of a section-variable aluminum alloy die forging. The method is characterized in that a moulding bed is designed and made according to the section-variable structure of the aluminum alloy die forging; a blank is separated and shaped by using the moulding bed; a preforging die is designed and made according to the section-variable profile of the aluminum alloy die forging; the preforging die is dimensioned to have a certain deformation allowance for the next forging; the blank is preforged by the preforging die, so that the blank is fixed and locally machined through the perforging die and each variable section is uniform in deformation; a final forging die is designed and made according to the final size of the variable sections of the aluminum alloy die forging; and forming and forging of the blank are conducted by the final forging die. The method enables the sections of all parts of the section-variable aluminum alloy die forging to be consistent, so that the hardenability of heat treatment and the uniformity of the structure property are guaranteed, and the whole performance of the section-variable aluminum alloy die forging is largely improved.

The invention relates to a cold-rolled hot-galvanized dual-phase steel. The cold-rolled hot-galvanized dual-phase steel is composed of the following chemical components in percentage by weight: 0.02-0.05% of C, 0.1-0.2% of Si, 0.8-1.3% of Mn, less than or equal to 0.01% of P, less than or equal to 0.01% of S, 0.04-0.08% of Al, 0.5-0.7% of Cr, less than or equal to 0.01% of V, less than or equal to 0.05% of B and the balance of Fe. The invention also relates to a preparation method of the cold-rolled hot-galvanized dual-phase steel. The preparation method comprises the following steps: performing continuous casting on steel liquid smelted previously by use of a converter so as to obtain a continuous casting billet; performing hot rolling on the continuous casting billet to obtain a hot-rolled slab and performing cold rolling on the hot-rolled slab to obtain cold and hard strip steel; performing continuous galvanizing annealing process treatment on the cold and hard strip steel so as to obtain the finished cold-rolled hot-galvanized dual-phase steel. The cold-rolled hot-galvanized dual-phase steel has the advantage that the galvanizing quality, the plasticity, the welding property and the stamping property are improved on the basis of satisfying the strength requirement.