CN114774784B - Large-caliber alloy steel pipe fitting and processing technology thereof - Google Patents

Large-caliber alloy steel pipe fitting and processing technology thereof Download PDF

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CN114774784B
CN114774784B CN202210356198.1A CN202210356198A CN114774784B CN 114774784 B CN114774784 B CN 114774784B CN 202210356198 A CN202210356198 A CN 202210356198A CN 114774784 B CN114774784 B CN 114774784B
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alloy steel
percent
steel pipe
caliber
treatment
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CN114774784A (en
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沈磊
刘叶佳
周秋华
陆楠
卢佳
徐鹏飞
陈盼
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Jiangsu Longshan Pipe Fittings Co ltd
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Jiangsu Longshan Pipe Fittings Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/10—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of tubular bodies
    • C21D8/105—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of tubular bodies of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • C22C33/06—Making ferrous alloys by melting using master alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • C23C22/40—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing molybdates, tungstates or vanadates
    • C23C22/42—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing molybdates, tungstates or vanadates containing also phosphates
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/02—Pretreatment of the material to be coated

Abstract

The invention discloses a large-caliber alloy steel pipe fitting, in particular to the technical field of flange bolts, which comprises the following raw materials: carbon, silicon, manganese, chromium, aluminum, zirconium, molybdenum, nickel, niobium, lead, cerium, strontium, calcium, sulfur, phosphorus, the balance being iron and unavoidable impurities. The aluminum-silicon phase of the invention has higher specific strength, specific rigidity, corrosion resistance and fatigue resistance, and lead is taken as a plastic soft metal, which not only can improve the compressibility of the material, but also can fill the gaps among powder particles, so that the lead can be taken as a lubricant to be filled into the aluminum-silicon phase to reduce the friction coefficient of the material, thereby improving the friction resistance of the alloy steel pipe, and lead calcium can form Pb in the alloy steel 3 The Ca fine grain precipitate can not only improve the mechanical property of alloy steel, but also has better corrosion resistance effect, and is micro-sized by zirconium and calciumThe service life of the alloyed electroslag remelted steel is prolonged, and the grindability is improved.

Description

Large-caliber alloy steel pipe fitting and processing technology thereof
Technical Field
The invention relates to the technical field of alloy steel pipes, in particular to a large-caliber alloy steel pipe and a processing technology thereof.
Background
Steel pipes have a hollow cross section and are used in large numbers as pipes for transporting fluids, such as oil, gas, water and certain solid materials. Compared with solid steel such as round steel, the steel pipe has the same bending and torsional strength, is light in weight, is an economic section steel, is widely used for manufacturing structural parts and mechanical parts, such as steel pipes for petroleum drill pipes, automobile transmission shafts, bicycle frames, steel scaffold frames used in building construction and the like, is used for manufacturing annular parts, can improve the material utilization rate, simplifies the manufacturing process, saves materials and processing time, and is widely used for manufacturing steel pipes. At present, the consumption of the large-caliber alloy steel pipe in China accounts for only half of the total weight of steel in developed countries, and the use field of the large-caliber alloy steel pipe is expanded to provide wider space for industry development.
In the existing large-caliber alloy steel pipe processing process, along with the improvement of alloy content, the processing plasticity of the alloy steel is reduced, the deformation resistance is increased, the processing becomes difficult, the mechanical property is insufficient, and the service life is lower.
Disclosure of Invention
In order to overcome the defects in the prior art, the embodiment of the invention provides a large-caliber alloy steel pipe fitting and a processing technology thereof, and the problems to be solved by the invention are as follows: how to improve the processing performance and mechanical property of the large-caliber alloy steel pipe fitting, and improve the yield and service life of the large-caliber alloy steel pipe fitting.
In order to achieve the above purpose, the present invention provides the following technical solutions: the large-caliber alloy steel pipe fitting comprises the following raw materials in percentage by weight: 0.05-0.2% of carbon, 0.1-0.3% of silicon, 0.2-0.6% of manganese, 0.5-1.5% of chromium, 0.2-0.8% of aluminum, 0.1-0.3% of zirconium, 0.25-0.4% of molybdenum, 0.05-0.15% of nickel, 0.1-0.3% of niobium, 0.2-0.5% of lead, 0.05-0.25% of cerium, 0.15-0.35% of strontium, 0.04-0.1% of calcium, less than or equal to 0.015% of sulfur, less than or equal to 0.015% of phosphorus, and the balance of iron and unavoidable impurities.
In a preferred embodiment, the composition comprises the following raw materials in percentage by weight: 0.1 to 0.15 percent of carbon, 0.15 to 0.25 percent of silicon, 0.3 to 0.5 percent of manganese, 0.8 to 1.2 percent of chromium, 0.4 to 0.6 percent of aluminum, 0.15 to 0.25 percent of zirconium, 0.3 to 0.35 percent of molybdenum, 0.08 to 0.12 percent of nickel, 0.15 to 0.25 percent of niobium, 0.3 to 0.4 percent of lead, 0.1 to 0.2 percent of cerium, 0.2 to 0.3 percent of strontium, 0.06 to 0.08 percent of calcium, less than or equal to 0.015 percent of sulfur, less than or equal to 0.015 percent of phosphorus, and the balance of iron and unavoidable impurities.
In a preferred embodiment, the composition comprises the following raw materials in percentage by weight: 0.125% of carbon, 0.2% of silicon, 0.4% of manganese, 0.1% of chromium, 0.5% of aluminum, 0.2% of zirconium, 0.32% of molybdenum, 0.1% of nickel, 0.2% of niobium, 0.35% of lead, 0.15% of cerium, 0.25% of strontium, 0.07% of calcium, less than or equal to 0.015% of sulfur, less than or equal to 0.015% of phosphorus, and the balance of iron and unavoidable impurities.
In a preferred embodiment, the unavoidable impurities are less than or equal to 0.005% and the sulfur and phosphorus content is non-zero.
A processing technology of a large-caliber alloy steel pipe fitting comprises the following specific preparation steps:
step one: weighing the raw materials according to the weight percentage, putting the weighed scrap steel into an electric furnace for heating and melting, adding the weighed carbon, silicon, manganese, chromium, aluminum, sulfur, phosphorus and molybdenum into the electric furnace for heating and continuously melting, adding a deoxidizer for deoxidizing after the melting is finished, adding the weighed zirconium, nickel, niobium, lead, cerium, strontium and calcium into the electric furnace for continuously heating and melting after deoxidizing, and then sampling and measuring the percentage content of each element to obtain mixed molten steel;
step two: injecting the mixed molten steel obtained in the first step into a die for vacuum degassing casting, obtaining a steel billet after casting, heating the obtained steel billet to 1300-1400 ℃, and carrying out center perforation to obtain a large-caliber hollow pipe blank;
step three: placing the large-caliber hollow pipe blank obtained in the second step into an annealing furnace for primary annealing treatment, and then carrying out acid washing treatment on the large-caliber hollow pipe blank after primary annealing;
step four: performing high-pressure descaling treatment on the large-caliber hollow tube blank subjected to the pickling treatment in the third step, and performing carburizing and quenching treatment after the high-pressure descaling treatment is completed;
step five: cold rolling the large-caliber hollow pipe blank obtained in the step four by using a cold rolling mill, cold drawing the large-caliber hollow pipe blank after cold rolling, and adjusting the diameter of the large-caliber hollow pipe blank and the length of a stretched steel pipe;
step six: and (3) placing the large-caliber hollow pipe blank subjected to cold rolling and cold drawing in the step five into an annealing furnace for secondary annealing treatment, cooling to room temperature after the secondary annealing treatment, and then polishing to obtain the large-caliber alloy steel pipe fitting.
In a preferred embodiment, the internal temperature of the electric furnace in the first step is 1400-1450 ℃, the temperature after the first temperature rise is 1520-1580 ℃, the temperature after the second temperature rise is 1650-1700 ℃, and the deoxidizer in the first step is ferrosilicon alloy.
In a preferred embodiment, the internal temperature of the annealing furnace in the third step is 780-850 ℃, the heat preservation time is 2-4h, the pickling process in the third step is carried out by soaking in pickling solution for 15-30min, and the annealing furnace is washed by water after pickling.
In a preferred embodiment, the outer side wall and the inner side wall of the large-caliber hollow shell are washed under the pressure of 3-8Pa by using phosphating solution in the high-pressure dephosphorization treatment in the fourth step, the phosphating solution is preheated before being used, the preheating temperature is 60-70 ℃, the carburizing and quenching treatment in the fourth step is 820-860 ℃ and the time is 8-12min.
In a preferred embodiment, the number of cold drawing in the fifth step is 2-4, and the components of the phosphating solution in the third step are as follows by weight percent: 10-15% of phosphoric acid, 2-4% of zinc oxide, 1-3% of sodium dihydrogen phosphate, 1.5-2% of ammonium molybdate, 1-2% of oxidation accelerator, 0.5-1.2% of low-temperature accelerator, 3-6% of phytic acid and 10-18% of water.
In a preferred embodiment, the internal temperature of the annealing furnace in the step six is 900-950 ℃ and the heat preservation time is 2-3h.
The invention has the technical effects and advantages that:
1. the large-caliber alloy steel pipe fitting prepared by adopting the raw material formula of the invention is added with chromium, aluminum, molybdenum, nickel, zirconium, niobium, lead, strontium and calcium, the cutting performance of the alloy steel can be improved by adding the lead and the calcium, the deformation resistance of the alloy steel is reduced, the yield of the alloy steel pipe is increased, the strength and the corrosion resistance of the steel pipe fitting can be effectively improved by adding the chromium, the aluminum-silicon phase has higher specific strength, specific stiffness, corrosion resistance and fatigue resistance, and the lead is taken as a plastic soft metal, not only the compressibility of the material can be improved, but also the gaps among powder particles can be filled, so that the lead can be taken as a lubricant to be filled into the aluminum-silicon phase, the friction coefficient of the material can be reduced, the friction resistance of the alloy steel pipe can be improved, and the lead and the calcium can form Pb in the alloy steel 3 The Ca fine grain precipitation can improve the mechanical property of alloy steel, has better corrosion resistance effect, improves the service life of the electroslag remelting steel microalloyed by zirconium and calcium, improves the grindability, promotes finer grains and uniform structure by microalloying inoculation treatment of zirconium and calcium, can improve the mechanical property of alloy steel by adding cerium, can improve the cracking and strip breakage phenomena caused by adding lead element, and improves the processing property of alloy steel pipes;
2. according to the invention, the alloy steel pipe is prevented from cracking after the two annealing treatments, so that the cracking problem is effectively solved, the alloy steel pipe has good processing performance, high yield and stable performance, and waste products are avoided.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1:
the invention provides a large-caliber alloy steel pipe fitting, which comprises the following raw materials in percentage by weight: 0.05% of carbon, 0.1% of silicon, 0.2% of manganese, 0.5% of chromium, 0.2% of aluminum, 0.1% of zirconium, 0.25% of molybdenum, 0.05% of nickel, 0.1% of niobium, 0.2% of lead, 0.05% of cerium, 0.15% of strontium, 0.04% of calcium, 0.01% of sulfur, 0.01% of phosphorus and the balance of iron and unavoidable impurities.
In a preferred embodiment, the unavoidable impurities are less than or equal to 0.005% and the sulfur and phosphorus content is non-zero.
A processing technology of a large-caliber alloy steel pipe fitting comprises the following specific preparation steps:
step one: weighing the raw materials according to the weight percentage, putting the weighed scrap steel into an electric furnace for heating and melting, adding the weighed carbon, silicon, manganese, chromium, aluminum, sulfur, phosphorus and molybdenum into the electric furnace for heating and continuously melting, adding a deoxidizer for deoxidizing after the melting is finished, adding the weighed zirconium, nickel, niobium, lead, cerium, strontium and calcium into the electric furnace for continuously heating and melting after deoxidizing, and then sampling and measuring the percentage content of each element to obtain mixed molten steel;
step two: injecting the mixed molten steel obtained in the first step into a die for vacuum degassing casting, obtaining a steel billet after casting, heating the obtained steel billet to 1350 ℃, and carrying out center perforation to obtain a large-caliber hollow pipe blank;
step three: placing the large-caliber hollow pipe blank obtained in the second step into an annealing furnace for primary annealing treatment, and then carrying out acid washing treatment on the large-caliber hollow pipe blank after primary annealing;
step four: performing high-pressure descaling treatment on the large-caliber hollow tube blank subjected to the pickling treatment in the third step, and performing carburizing and quenching treatment after the high-pressure descaling treatment is completed;
step five: cold rolling the large-caliber hollow pipe blank obtained in the step four by using a cold rolling mill, cold drawing the large-caliber hollow pipe blank after cold rolling, and adjusting the diameter of the large-caliber hollow pipe blank and the length of a stretched steel pipe;
step six: and (3) placing the large-caliber hollow pipe blank subjected to cold rolling and cold drawing in the step five into an annealing furnace for secondary annealing treatment, cooling to room temperature after the secondary annealing treatment, and then polishing to obtain the large-caliber alloy steel pipe fitting.
In a preferred embodiment, the internal temperature of the electric furnace in the first step is 1450 ℃, the temperature after the first temperature rise is 1550 ℃, the temperature after the second temperature rise is 1680 ℃, and the deoxidizer in the first step is ferrosilicon alloy.
In a preferred embodiment, the internal temperature of the annealing furnace in the third step is 810 ℃, the heat preservation time is 3 hours, the annealing furnace is soaked in pickling solution for 22 minutes in the pickling treatment in the third step, and the annealing furnace is rinsed with water after pickling.
In a preferred embodiment, the outer side wall and the inner side wall of the large-caliber hollow shell are washed under the pressure of 5Pa by using a phosphating solution in the high-pressure dephosphorization treatment in the fourth step, the phosphating solution is preheated before being used, the preheating temperature is 65 ℃, the carburizing and quenching treatment in the fourth step is carried out at the temperature of 840 ℃ for 10min.
In a preferred embodiment, the number of cold drawing in the fifth step is 3, and the components of the phosphating solution in the third step are as follows by weight percent: 13% of phosphoric acid, 3% of zinc oxide, 2% of sodium dihydrogen phosphate, 1.8% of ammonium molybdate, 1.5% of oxidation promoter, 0.8% of low-temperature promoter, 5% of phytic acid and 14% of water.
In a preferred embodiment, the temperature inside the annealing furnace in the step six is 930 ℃, and the heat preservation time is 2.5h.
Example 2:
unlike example 1, a large caliber alloy steel pipe fitting comprises the following raw materials in weight percent: carbon 0.125%, silicon 0.2%, manganese 0.4%, chromium 0.1%, aluminum 0.5%, zirconium 0.2%, molybdenum 0.32%, nickel 0.1%, niobium 0.2%, lead 0.35%, cerium 0.15%, strontium 0.25%, calcium 0.07%, sulfur 0.01%, phosphorus 0.01%, and the balance iron and unavoidable impurities.
Example 3:
unlike examples 1-2, a large caliber alloy steel pipe fitting comprises the following raw materials in weight percent: 0.2% of carbon, 0.3% of silicon, 0.6% of manganese, 1.5% of chromium, 0.8% of aluminum, 0.3% of zirconium, 0.4% of molybdenum, 0.15% of nickel, 0.3% of niobium, 0.5% of lead, 0.25% of cerium, 0.35% of strontium, 0.1% of calcium, 0.01% of sulfur, 0.01% of phosphorus and the balance of iron and unavoidable impurities.
Example 4:
the invention provides a large-caliber alloy steel pipe fitting, which comprises the following raw materials in percentage by weight: carbon 0.05%, silicon 0.1%, manganese 0.2%, chromium 0.5%, aluminum 0.2%, zirconium 0.1%, molybdenum 0.25%, nickel 0.05%, niobium 0.1%, cerium 0.05%, strontium 0.15%, sulfur 0.01%, phosphorus 0.01%, the balance being iron and unavoidable impurities.
In a preferred embodiment, the unavoidable impurities are less than or equal to 0.005% and the sulfur and phosphorus content is non-zero.
A processing technology of a large-caliber alloy steel pipe fitting comprises the following specific preparation steps:
step one: weighing the raw materials according to the weight percentage, putting the weighed scrap steel into an electric furnace for heating and melting, adding the weighed carbon, silicon, manganese, chromium, aluminum, sulfur, phosphorus and molybdenum into the electric furnace for heating and continuously melting, adding a deoxidizer for deoxidizing after the melting is finished, adding the weighed zirconium, nickel, niobium, cerium and strontium into the electric furnace for continuously heating and melting after deoxidizing, and then sampling and measuring the percentage content of each element to obtain mixed molten steel;
step two: injecting the mixed molten steel obtained in the first step into a die for vacuum degassing casting, obtaining a steel billet after casting, heating the obtained steel billet to 1350 ℃, and carrying out center perforation to obtain a large-caliber hollow pipe blank;
step three: placing the large-caliber hollow pipe blank obtained in the second step into an annealing furnace for primary annealing treatment, and then carrying out acid washing treatment on the large-caliber hollow pipe blank after primary annealing;
step four: performing high-pressure descaling treatment on the large-caliber hollow tube blank subjected to the pickling treatment in the third step, and performing carburizing and quenching treatment after the high-pressure descaling treatment is completed;
step five: cold rolling the large-caliber hollow pipe blank obtained in the step four by using a cold rolling mill, cold drawing the large-caliber hollow pipe blank after cold rolling, and adjusting the diameter of the large-caliber hollow pipe blank and the length of a stretched steel pipe;
step six: and (3) placing the large-caliber hollow pipe blank subjected to cold rolling and cold drawing in the step five into an annealing furnace for secondary annealing treatment, cooling to room temperature after the secondary annealing treatment, and then polishing to obtain the large-caliber alloy steel pipe fitting.
In a preferred embodiment, the internal temperature of the electric furnace in the first step is 1450 ℃, the temperature after the first temperature rise is 1550 ℃, the temperature after the second temperature rise is 1680 ℃, and the deoxidizer in the first step is ferrosilicon alloy.
In a preferred embodiment, the internal temperature of the annealing furnace in the third step is 810 ℃, the heat preservation time is 3 hours, the annealing furnace is soaked in pickling solution for 22 minutes in the pickling treatment in the third step, and the annealing furnace is rinsed with water after pickling.
In a preferred embodiment, the outer side wall and the inner side wall of the large-caliber hollow shell are washed under the pressure of 5Pa by using a phosphating solution in the high-pressure dephosphorization treatment in the fourth step, the phosphating solution is preheated before being used, the preheating temperature is 65 ℃, the carburizing and quenching treatment in the fourth step is carried out at the temperature of 840 ℃ for 10min.
In a preferred embodiment, the number of cold drawing in the fifth step is 3, and the components of the phosphating solution in the third step are as follows by weight percent: 13% of phosphoric acid, 3% of zinc oxide, 2% of sodium dihydrogen phosphate, 1.8% of ammonium molybdate, 1.5% of oxidation promoter, 0.8% of low-temperature promoter, 5% of phytic acid and 14% of water.
In a preferred embodiment, the temperature inside the annealing furnace in the step six is 930 ℃, and the heat preservation time is 2.5h.
Example 5:
the invention provides a large-caliber alloy steel pipe fitting, which comprises the following raw materials in percentage by weight: 0.05% of carbon, 0.1% of silicon, 0.2% of manganese, 0.5% of chromium, 0.2% of aluminum, 0.1% of zirconium, 0.25% of molybdenum, 0.05% of nickel, 0.1% of niobium, 0.2% of lead, 0.15% of strontium, 0.04% of calcium, 0.01% of sulfur, 0.01% of phosphorus and the balance of iron and unavoidable impurities.
In a preferred embodiment, the unavoidable impurities are less than or equal to 0.005% and the sulfur and phosphorus content is non-zero.
A processing technology of a large-caliber alloy steel pipe fitting comprises the following specific preparation steps:
step one: weighing the raw materials according to the weight percentage, putting the weighed scrap steel into an electric furnace for heating and melting, adding the weighed carbon, silicon, manganese, chromium, aluminum, sulfur, phosphorus and molybdenum into the electric furnace for heating and continuously melting, adding a deoxidizer for deoxidizing after the melting is finished, adding the weighed zirconium, nickel, niobium, lead, strontium and calcium into the electric furnace for continuously heating and melting after deoxidizing, and then sampling and measuring the percentage content of each element to obtain mixed molten steel;
step two: injecting the mixed molten steel obtained in the first step into a die for vacuum degassing casting, obtaining a steel billet after casting, heating the obtained steel billet to 1350 ℃, and carrying out center perforation to obtain a large-caliber hollow pipe blank;
step three: placing the large-caliber hollow pipe blank obtained in the second step into an annealing furnace for primary annealing treatment, and then carrying out acid washing treatment on the large-caliber hollow pipe blank after primary annealing;
step four: performing high-pressure descaling treatment on the large-caliber hollow tube blank subjected to the pickling treatment in the third step, and performing carburizing and quenching treatment after the high-pressure descaling treatment is completed;
step five: cold rolling the large-caliber hollow pipe blank obtained in the step four by using a cold rolling mill, cold drawing the large-caliber hollow pipe blank after cold rolling, and adjusting the diameter of the large-caliber hollow pipe blank and the length of a stretched steel pipe;
step six: and (3) placing the large-caliber hollow pipe blank subjected to cold rolling and cold drawing in the step five into an annealing furnace for secondary annealing treatment, cooling to room temperature after the secondary annealing treatment, and then polishing to obtain the large-caliber alloy steel pipe fitting.
In a preferred embodiment, the internal temperature of the electric furnace in the first step is 1450 ℃, the temperature after the first temperature rise is 1550 ℃, the temperature after the second temperature rise is 1680 ℃, and the deoxidizer in the first step is ferrosilicon alloy.
In a preferred embodiment, the internal temperature of the annealing furnace in the third step is 810 ℃, the heat preservation time is 3 hours, the annealing furnace is soaked in pickling solution for 22 minutes in the pickling treatment in the third step, and the annealing furnace is rinsed with water after pickling.
In a preferred embodiment, the outer side wall and the inner side wall of the large-caliber hollow shell are washed under the pressure of 5Pa by using a phosphating solution in the high-pressure dephosphorization treatment in the fourth step, the phosphating solution is preheated before being used, the preheating temperature is 65 ℃, the carburizing and quenching treatment in the fourth step is carried out at the temperature of 840 ℃ for 10min.
In a preferred embodiment, the number of cold drawing in the fifth step is 3, and the components of the phosphating solution in the third step are as follows by weight percent: 13% of phosphoric acid, 3% of zinc oxide, 2% of sodium dihydrogen phosphate, 1.8% of ammonium molybdate, 1.5% of oxidation promoter, 0.8% of low-temperature promoter, 5% of phytic acid and 14% of water.
In a preferred embodiment, the temperature inside the annealing furnace in the step six is 930 ℃, and the heat preservation time is 2.5h.
Control group:
the invention provides a large-caliber alloy steel pipe fitting, which comprises the following raw materials in percentage by weight: carbon 0.15%, silicon 0.23%, manganese 0.55%, chromium 0.85%, sulfur 0.01%, phosphorus 0.01%, the balance being iron and unavoidable impurities.
In a preferred embodiment, the unavoidable impurities are less than or equal to 0.005% and the sulfur and phosphorus content is non-zero.
A processing technology of a large-caliber alloy steel pipe fitting comprises the following specific preparation steps:
step one: weighing the raw materials according to the weight percentage, putting the weighed scrap steel into an electric furnace for heating and melting, adding the weighed carbon, silicon, manganese, chromium, sulfur and phosphorus into the electric furnace, heating and continuously melting, adding a deoxidizer for deoxidizing treatment after the melting is finished, sampling and measuring the percentage content of each element, and obtaining mixed molten steel;
step two: injecting the mixed molten steel obtained in the first step into a die for vacuum degassing casting, obtaining a steel billet after casting, heating the obtained steel billet to 1350 ℃, and carrying out center perforation to obtain a large-caliber hollow pipe blank;
step three: placing the large-caliber hollow pipe blank obtained in the second step into an annealing furnace for primary annealing treatment, and then carrying out acid washing treatment on the large-caliber hollow pipe blank after primary annealing;
step four: performing high-pressure descaling treatment on the large-caliber hollow tube blank subjected to the pickling treatment in the third step, and performing carburizing and quenching treatment after the high-pressure descaling treatment is completed;
step five: cold rolling the large-caliber hollow pipe blank obtained in the step four by using a cold rolling mill, cold drawing the large-caliber hollow pipe blank after cold rolling, and adjusting the diameter of the large-caliber hollow pipe blank and the length of a stretched steel pipe;
step six: and (3) placing the large-caliber hollow pipe blank subjected to cold rolling and cold drawing in the step five into an annealing furnace for secondary annealing treatment, cooling to room temperature after the secondary annealing treatment, and then polishing to obtain the large-caliber alloy steel pipe fitting.
In a preferred embodiment, the internal temperature of the electric furnace in the first step is 1450 ℃, the temperature after the first temperature rise is 1550 ℃, and the deoxidizer in the first step is ferrosilicon.
In a preferred embodiment, the internal temperature of the annealing furnace in the third step is 810 ℃, the heat preservation time is 3 hours, the annealing furnace is soaked in pickling solution for 22 minutes in the pickling treatment in the third step, and the annealing furnace is rinsed with water after pickling.
In a preferred embodiment, the outer side wall and the inner side wall of the large-caliber hollow shell are washed under the pressure of 5Pa by using a phosphating solution in the high-pressure dephosphorization treatment in the fourth step, the phosphating solution is preheated before being used, the preheating temperature is 65 ℃, the carburizing and quenching treatment in the fourth step is carried out at the temperature of 840 ℃ for 10min.
In a preferred embodiment, the number of cold drawing in the fifth step is 3, and the components of the phosphating solution in the third step are as follows by weight percent: 13% of phosphoric acid, 3% of zinc oxide, 2% of sodium dihydrogen phosphate, 1.8% of ammonium molybdate, 1.5% of oxidation promoter, 0.8% of low-temperature promoter, 5% of phytic acid and 14% of water.
In a preferred embodiment, the temperature inside the annealing furnace in the step six is 930 ℃, and the heat preservation time is 2.5h.
The large-caliber alloy steel pipe fittings prepared in the above examples 1-5 are respectively taken as an experiment group 1, an experiment group 2, an experiment group 3, an experiment group 4 and an experiment group 5, alloy steel pipe fittings produced by a comparison group (the comparison group raw materials are similar to the 20Cr alloy steel raw materials) are adopted as comparison groups to be tested, the selected large-caliber alloy steel pipe fittings are respectively tested for tensile strength, yield strength, abrasion resistance and corrosion resistance (the tensile strength and yield strength are tested by using GB/T228-02, ASTME8M-08, ISO 6892-2009, JIS Z2241-98 standards under normal temperature, static load and axial load on a tensile testing machine), the products are respectively placed on an Ames mill report testing machine during the abrasion resistance test, the 245-1960 load is applied to the surfaces of the products, the upper shaft is rotated for 200r/min, the abrasion resistance is measured after 8min, the selected alloy steel pipes are soaked and corroded by using 5% HNO3+1% HCl solution under the room temperature condition during the corrosion resistance test, and the finished product rate of the products is recorded. The test results are shown in Table I:
list one
As can be seen from the first table, the large-caliber alloy steel pipe produced by the invention has stronger tensile strength and yield strength, better wear resistance and corrosion resistance, high yield, and compared with the example 1, the example 4 lacks lead and calcium,the tensile strength and yield strength of the large-caliber alloy steel pipe fitting are less changed, the wear resistance and corrosion resistance are reduced, the yield is reduced, compared with example 1, the tensile strength, yield strength, wear resistance and corrosion resistance are reduced, compared with example 1, the yield is reduced, compared with example 1, the cerium is not added in example 5; the invention is added with chromium, aluminum, molybdenum, nickel, zirconium, niobium, lead, strontium and calcium, the cutting performance of alloy steel can be improved by adding lead and calcium, the deformation resistance of the alloy steel is reduced, the yield of the alloy steel pipe is increased, the strength and corrosion resistance of the steel pipe can be effectively improved by adding chromium, the aluminum-silicon phase has higher specific strength, specific rigidity, corrosion resistance and fatigue resistance, and lead is taken as plastic soft metal, the compressibility of the material can be improved, and gaps among powder particles can be filled, so that lead can be taken as lubricant to be filled into the aluminum-silicon phase, the friction coefficient of the material can be reduced, the friction resistance of the alloy steel pipe is improved, and lead and calcium can form Pb in the alloy steel 3 The Ca fine grain precipitation can improve the mechanical property of alloy steel, the corrosion resistance effect is better, the service life of the electroslag remelting steel microalloyed by zirconium and calcium is prolonged, the grindability is improved, the microalloying inoculation treatment of zirconium and calcium promotes finer grains and uniform tissues, the mechanical property of alloy steel can be improved by adding cerium, the cracking and strip breakage phenomena caused by adding lead elements can be improved, and the processing performance of alloy steel pipes is improved.
Finally: the foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims (8)

1. The utility model provides a heavy-calibre alloy steel pipe fitting which characterized in that: comprises the following raw materials in percentage by weight: 0.05-0.2% of carbon, 0.1-0.3% of silicon, 0.2-0.6% of manganese, 0.5-1.5% of chromium, 0.2-0.8% of aluminum, 0.1-0.3% of zirconium, 0.25-0.4% of molybdenum, 0.05-0.15% of nickel, 0.1-0.3% of niobium, 0.2-0.5% of lead, 0.05-0.25% of cerium, 0.15-0.35% of strontium, 0.04-0.1% of calcium, less than or equal to 0.015% of sulfur, less than or equal to 0.015% of phosphorus, and the balance of iron and unavoidable impurities;
the processing technology of the large-caliber alloy steel pipe fitting comprises the following specific preparation steps:
step one: weighing the raw materials according to the weight percentage, putting the weighed scrap steel into an electric furnace for heating and melting, adding the weighed carbon, silicon, manganese, chromium, aluminum, sulfur, phosphorus and molybdenum into the electric furnace for heating and continuously melting, adding a deoxidizer for deoxidizing after the melting is finished, adding the weighed zirconium, nickel, niobium, lead, cerium, strontium and calcium into the electric furnace for continuously heating and melting after deoxidizing, and then sampling and measuring the percentage content of each element to obtain mixed molten steel;
step two: injecting the mixed molten steel obtained in the first step into a die for vacuum degassing casting, obtaining a steel billet after casting, heating the obtained steel billet to 1300-1400 ℃, and carrying out center perforation to obtain a large-caliber hollow pipe blank;
step three: placing the large-caliber hollow pipe blank obtained in the second step into an annealing furnace for primary annealing treatment, and then carrying out acid washing treatment on the large-caliber hollow pipe blank after primary annealing;
step four: performing high-pressure descaling treatment on the large-caliber hollow tube blank subjected to the pickling treatment in the third step, and performing carburizing and quenching treatment after the high-pressure descaling treatment is completed;
step five: cold rolling the large-caliber hollow pipe blank obtained in the step four by using a cold rolling mill, cold drawing the large-caliber hollow pipe blank after cold rolling, and adjusting the diameter of the large-caliber hollow pipe blank and the length of a stretched steel pipe;
step six: and (3) placing the large-caliber hollow pipe blank subjected to cold rolling and cold drawing in the step five into an annealing furnace for secondary annealing treatment, cooling to room temperature after the secondary annealing treatment, and then polishing to obtain the large-caliber alloy steel pipe fitting.
2. A large diameter alloy steel pipe fitting as claimed in claim 1 wherein: comprises the following raw materials in percentage by weight: 0.1 to 0.15 percent of carbon, 0.15 to 0.25 percent of silicon, 0.3 to 0.5 percent of manganese, 0.8 to 1.2 percent of chromium, 0.4 to 0.6 percent of aluminum, 0.15 to 0.25 percent of zirconium, 0.3 to 0.35 percent of molybdenum, 0.08 to 0.12 percent of nickel, 0.15 to 0.25 percent of niobium, 0.3 to 0.4 percent of lead, 0.1 to 0.2 percent of cerium, 0.2 to 0.3 percent of strontium, 0.06 to 0.08 percent of calcium, less than or equal to 0.015 percent of sulfur, less than or equal to 0.015 percent of phosphorus, and the balance of iron and unavoidable impurities.
3. A large diameter alloy steel pipe fitting as claimed in claim 1 wherein: the content of the unavoidable impurities is less than or equal to 0.005%, and the content of sulfur and phosphorus is not zero.
4. A large diameter alloy steel pipe fitting as claimed in claim 1 wherein: the internal temperature of the electric furnace in the first step is 1400-1450 ℃, the temperature after the first temperature rise is 1520-1580 ℃, the temperature after the second temperature rise is 1650-1700 ℃, and the deoxidizer in the first step is ferrosilicon alloy.
5. A large diameter alloy steel pipe fitting as claimed in claim 1 wherein: the internal temperature of the annealing furnace in the third step is 780-850 ℃, the heat preservation time is 2-4h, the annealing furnace is soaked in pickling solution for 15-30min during pickling treatment in the third step, and the annealing furnace is washed by water after pickling.
6. A large diameter alloy steel pipe fitting as claimed in claim 1 wherein: and in the fourth step, during high-pressure dephosphorization treatment, the outer side wall and the inner side wall of the large-caliber hollow shell are washed under the pressure of 3-8Pa by using phosphating solution, the phosphating solution is preheated before use, the preheating temperature is 60-70 ℃, and the carburizing and quenching treatment temperature is 820-860 ℃ for 8-12min.
7. The large diameter alloy steel pipe fitting according to claim 6, wherein: the number of cold drawing times in the fifth step is 2-4, and the components of the phosphating solution in the fourth step are as follows in percentage by weight: 10-15% of phosphoric acid, 2-4% of zinc oxide, 1-3% of sodium dihydrogen phosphate, 1.5-2% of ammonium molybdate, 1-2% of oxidation accelerator, 0.5-1.2% of low-temperature accelerator, 3-6% of phytic acid and 10-18% of water.
8. A large diameter alloy steel pipe fitting as claimed in claim 1 wherein: in the step six, the internal temperature of the annealing furnace is 900-950 ℃, and the heat preservation time is 2-3h.
CN202210356198.1A 2022-04-06 2022-04-06 Large-caliber alloy steel pipe fitting and processing technology thereof Active CN114774784B (en)

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