CN107282854B - A kind of manufacturing process of nuclear power retaining ring - Google Patents

Abstract

The present invention relates to the manufacturing process of nuclear power retaining ring, processing step includes forging bar and roughing, blank hot extrusion, the machining of ring billet, ring billet solution treatment, pre- bulging and main bulging etc..The beneficial effect that the present invention reaches is to can be realized the manufacture of the retaining ring of highest performance level (8 grades) in ASTM A289M standard, wherein 95-105 DEG C of drawing by high temperature yield strength average out to 1220MPa, and elongation percentage average out to 22%, performance profile is uniform；And retaining ring production is stablized, and is less prone to cracking in process of production.

Description

A kind of manufacturing process of nuclear power retaining ring

Technical field

The present invention relates to a kind of manufacturing process of nuclear power retaining ring, belong to metal working technical area.

Background technique

AP1000 and CP1400 is one of main force's heap-type of China's three generations's PWR of Nuclear Power Station.AP1000's and CAP1400 Reactor coolant main circulation pump (hereinafter referred to as main pump) be all made of single-stage, hermetically sealed, high moment of inertia, protected type it is electronic Pump, it is unique slewing in primary Ioops system, is the heart of nuclear island, belongs to nuclear safety first device, is presurized water reactor core One of the key equipment in power station.The maximum feature of Coolant Pump is exactly no axle envelope, it can be achieved that zero leakage, safety is higher, This advantage is increasingly valued under the trend that three generations's nuclear power technology continues to develop.To increase main pump rotary inertia, extend running down Time, two sides are respectively arranged 1 set of flywheel assembly above and below main pump motor, and flywheel assembly is mainly by several piece heavy metal tungsten alloy warm It covers and is formed in high-intensitive, high rigidity stainless 18 N steel guard ring.Flywheel retaining ring military service operating condition is complicated, in high speed rotation, high-intensity magnetic field, Under the conditions of moist corrosive medium, comprehensive mechanical property requires high (reaching 8 grades of ASTM A289M highest level), be in nuclear island only The large forgings of one necessary cold deformation strengthening, manufacturing process is extremely complex, all relies on imports at present, has become main pump motor The bottleneck problem of production domesticization.Compared to other fired power generating unit retaining rings, the high performance retaining ring size such as nuclear power motor flywheel is smaller, Performance requirement is higher, alloying element content is higher, and forming difficulty is very big, using traditional open die forging hot forging process and single cold expanding The problems such as shape technique easily cracks, and influences product quality, causes uneven performance, product high rejection rate.

Summary of the invention

The present invention is big for prior art forming difficulty, and cracking is easy in Bulging Process and performance rate is relatively low asks Topic, provides a kind of manufacturing process of nuclear power retaining ring.

The technical scheme to solve the above technical problems is that a kind of manufacturing process of nuclear power retaining ring, special Place is, processing step are as follows:

One, steel ingot is forged into bar by the upsetting pull of three fire time by forging bar；

Two, bar periphery is carried out roughing and is divided into hot extrusion to use then by its sawing by bar roughing, sawing Blank；

Three, blank heating to temperature is 1200 DEG C ± 20 DEG C by blank hot extrusion, and soaking time goes out not less than after 8h Furnace is placed in extrusion die, is persistently squeezed using press, and blank is got circle hole shape into ring billet；

Four, the machining of ring billet, size before machining ring billet to bulging by the requirement of bulging process；

Five, ring billet solution treatment will carry out solid solubility temperature heat preservation by mach ring billet with 1060 ± 20 DEG C of temperature, Soaking time 1-3 hours, quick water cooling later；

Six, the ring billet after solution treatment is preheating to temperature not higher than 300 DEG C, using outer fluid infusion liquid in deformation by pre- bulging Bulging device is pressed to carry out bulging, the rate of bulging is less than 2.5mm/min, and control central diameter deflection is 6-20%；

Seven, main bulging, the ring billet after pre- bulging is not higher than 300 DEG C in deformation preheating temperature, using external fluid infusion hydraulic pressure Bulging device carries out bulging, and the rate of bulging is less than 2.5mm/min, and control central diameter deflection is 32-52%.

It, can be to above-mentioned technology in order to make technical solution of the present invention that there is better effect and specific aim and real-time Scheme is further improved and is refined:

Further, it is 0.60-0.75% that the steel ingot in the forging bar step, which is nitrogen element content, using electroslag weight The steel ingot of process of smelting production, diameter 600-800mm, length are not less than 1780mm, and weight is 5-6 tons, and surface is without slag runner defect.

Further, the upsetting pull forging of three fire in the forging bar step time are as follows: by Heating Steel Ingots to temperature 1200 ± 20 DEG C, and soaking time is not less than 8h, carries out forging, the first fire time jumping-up to length is 1500-1800mm, and pulling is extremely Length is 1650-1950mm, then by Heating Steel Ingots to 1200 ± 20 DEG C of temperature, after soaking time is not less than 8h, and the second fire Jumping-up to length is 1100-1400mm, and pulling to length is 1600-1900mm, again by Heating Steel Ingots to temperature 1200 ± 20 DEG C, after soaking time is not less than 8h, third fire time jumping-up to length is 1000-1350mm, and pulling to diameter 700-750mm is long Degree is 1200-1600mm, pulls out 20-50mm of reduction in pass；After forging three times that steel ingot is air-cooled.

Further, the bar roughing, in sawing step, bar periphery is carried out by 710 ± 20mm of diameter thick Processing.

Further, the solution treatment is to be heated up with speed not higher than 150 DEG C/h, after solid solution heat preservation, is come out of the stove Quick water cooling is to being not higher than 100 DEG C of water outlets.

Further, solution heat treatment, the solution treatment are carried out to the ring billet after pre- tensioner ring after the pre- bulging To be heated up with speed not higher than 150 DEG C/h, after solid solution heat preservation, quick water cooling of coming out of the stove is to being not higher than 100 DEG C of water outlets.

Further, stress-removal heat treatment is carried out after the main bulging, to be heated up with the rate of heat addition not higher than 40 DEG C/h, Ring billet after main bulging is kept the temperature at a temperature of 350-400 DEG C, keeps the temperature 6-12 hours, to be not higher than the cooling rate furnace of 20 DEG C/h It is cooled at 100 DEG C and comes out of the stove.

In order to for some special-purposes retaining ring processing needs, during can reprocessing to the aperture of retaining ring into Row adjustment, carries out the reaming of ring billet after blank hot extrusion step, and ring billet molding after hot extrusion is used saddle forging.

The present invention significantly improves traditional ring billet manufacturing process, is substituted with the technique of forging material joint hot extrusion Traditional jumping-up, punching, pulling free forging process.Traditional free forging process produces that such malleable temperature range is narrow, easy appearance The retaining ring forged piece of crackle has at any time although the mode for taking the more fire time of small deformation amount not can avoid the appearance of forge crack still Probably due to needing to remove breach and stop forging, production efficiency is influenced, while removing the process of breach using flame or carbon arc air gouging In can generate that stress is concentrated, local burning defect imitates internal soundness and production so that cracking repeatedly in subsequent forging process Rate brings very big influence.And after using the new process of forging bar joint hot extrusion, steel is on the one hand improved by forging bar Ingot as-cast structure, on the one hand by the molding mode of hot extrusion in mould, material all directions deform constrained not easy to crack, carbon steel A possibility that jacket also plays filmlubrication, reduces frictional resistance, utmostly reduce cracking.Blank is three when hot extrusion It is deformed under to compressive stress state, is conducive to make, eliminate steel ingot internal flaw up, improves interiors of products quality.Hot extrusion suppresses ring billet One step monolithic molding, production efficiency are also improved.

The present invention also significantly improves traditional cold bulging process, with the technique of expanding and reinforcing underlying strength twice Instead of single bulging process.The usual intensity of ring billet before cold expanding shape is lower, and plasticity and toughness are poor, and traditional handicraft is in order to reach higher Performance rate can only take biggish cold expanding deformation amount, and with the increase of cold deformation, the plasticity and toughness of product are further It reduces and plasticity and toughness required value or even product as defined in product is not achieved and directly occurs cracking and causing to scrap, traditional cold expanding shape The overall deformation of technique is difficult, yield rate is lower.After the new process of expanding and reinforcing underlying strength twice, pass through first Secondary cold expanding shape improves the underlying strength of product, and subsequent solution treatment has softened tissue again, improved plasticity and toughness；Such On the basis of, the case where cold deformation needed for subsequent second main bulging accordingly reduces, and spalling is scrapped, is obviously improved, and Obtain the plasticity and toughness index such as ideal elongation percentage, ballistic work.

Due to being improved the above manufacturing process, the manufacturing process of nuclear power retaining ring of the present invention is achievable beneficial to effect Fruit is as follows: retaining ring is hot-forged cracked frequency decline 60%, and the finished product rate of retaining ring product less than 50% by being increased to 90% or more, retaining ring performance rate is improved by 6 grades of ASTM A289M to 8 grades.Use the accessible specifics of this manufacturing process Energy level is summarized as follows: room temperature tensile yield strength >=1345MPa, tensile strength >=1380MPa, elongation percentage >=14%, room temperature Ballistic work >=62J, 95-105 DEG C of drawing by high temperature yield strength and tensile strength average value reach 1220MPa, and elongation percentage average value reaches >=22%, grain size >=3 grade, residual stress≤26MPa.

Detailed description of the invention

Fig. 1 is hot extrusion process schematic diagram；

Schematic diagram when Fig. 2 is hot extrusion process final stage；

Fig. 3 is hydraulic expanding-forming schematic diagram；

Fig. 4 is hydraulic expanding-forming end of a period status diagram.

Specific embodiment

The principles and features of the present invention are described below, and the given examples are served only to explain the present invention, is not intended to limit Determine the scope of the present invention.

A kind of manufacturing process of nuclear power retaining ring, processing step are as follows:

One, material selects, and selects nitrogen element content for 0.60-0.75%, the steel ingot produced using electroslag remelting process.Institute The steel ingot diameter 600-800mm stated, length are not less than 1780mm, and weight is 5-6 tons, and surface is without slag runner defect.Electroslag remelting is Refer to electroslag melt steel (electroslag remelting), is the resistance heat that is generated when passing through slag using electric current as heat source The method for carrying out melting, main purpose is to purify metals and obtain the steel ingot of clean even tissue densification.Through electroslag remelting Steel, purity is high, sulfur-bearing is low, non-metallic inclusion is few, surface of steel ingot is smooth, clean even compact, metallographic structure and chemical component Uniformly.The as cast condition mechanical performance of Electro Slag Remelting Steel can reach or more than same steel grade forging index.The quality of electroslag ingot depends on closing The electroslag remelting process of reason and the appointed condition for guaranteeing electroslag process.Material selection is to provide material for present invention implementation, therefore The main composition of non-present invention.

Two, selected steel ingot is forged into bar by the upsetting pull of three fire time by forging bar.Its specific process are as follows: By selected Heating Steel Ingots to 1200 ± 20 DEG C of temperature, after soaking time is not less than 8h, the first fire time forging, the first fire are carried out Jumping-up to length is 1500-1800mm, and pulling to length is 1650-1950mm, then by Heating Steel Ingots to temperature 1200 ± 20 DEG C, after soaking time is not less than 8h, the second fire time jumping-up to length is 1100-1400mm, and pulling to length is 1600- 1900mm, again by Heating Steel Ingots to 1200 ± 20 DEG C of temperature, after soaking time is not less than 8h, third fire time jumping-up to length is 1000-1350mm, pulling to diameter 700-750mm, length 1200-1600mm pull out 20-50mm of reduction in pass, are passing through It crosses steel ingot is air-cooled after forging three times.

Three, bar periphery is carried out roughing and is divided into hot extrusion to use then by its sawing by bar roughing, sawing Blank.Bar periphery is subjected to roughing by 710 ± 20mm of diameter, its sawing is then become into the base of hot extrusion at section Material；In the present embodiment, it is cut by taking tri- kinds of retaining rings of ABC as an example, the parameter of three kinds of blanks such as following table,

Retaining ring code name	Diameter mm	Length mm	Weight kg
				Retaining ring A	730	670	2170
Retaining ring B	720	450	1450
				Retaining ring C	710	440	1300

Four, blank hot extrusion, blank heating to temperature are 1200 DEG C ± 20 DEG C, and soaking time is not less than coming out of the stove after 8h, It is placed in extrusion die, is persistently squeezed using press, blank is got into annular distance and forms ring billet.The extruding that the present embodiment uses Device (referring to Fig. 1 and Fig. 2) includes: pedestal 1, sleeve 2, punching pedestal 3, underlay 4, backing plate 5；Operation process is as follows, outside blank 7 Bread wraps carbon steel jacket 6, is collectively disposed in the mold of composition, puts formed punch 8 and positioning tube 9 well, under being continued using ten thousand tons of press Pressure formed punch 8 squeezes blank 7, blank 7, jacket 6 and 9 counter motion of positioning tube, when formed punch 8 is concordant with positioning tube 9, peace Joint 10 continues to push impact extrusion, and the final stage of extrusion process removes positioning tube 9 and underlay 4, and formed punch 8 continues to push, finally Bottom material and backing plate 5 are gone out from punching pedestal 3, are completed hot extrusion, are squeezed out retaining ring A, B, C respectively.Wherein the diameter of formed punch 8 is According to the requirement of the internal orifice dimension of final retaining ring, and use the formed punch of corresponding size diameter.

Five, the machining of ring billet, size before machining ring billet to bulging by the requirement of bulging process.The content of processing is The surplus of diameter and length direction is removed, because no matter hot extrusion or cold expanding shape are all approximate formings, in hot extrusion All there are certain machining allowance, require further to machine to guarantee its dimensional accuracy.Hydraulic bulging process is liquid When compression, constancy of volume and pressure is uniformly transferred to all directions, reach into material at the best of times along die deformation, The purpose of shape.

Six, ring billet solution treatment will carry out solid solubility temperature heat preservation by mach ring billet with 1060 ± 20 DEG C of temperature, Soaking time 1-3 hours, quick water cooling later.Ring billet heating rate by processing is not higher than 150 DEG C/h, by solid solution After heat preservation, quick water cooling is to being not higher than 100 DEG C of water outlets after coming out of the stove；Solution treatment (solution treatment): refer to alloy It is heated to the holding of high temperature monophase field constant temperature, rapid cooling after being dissolved into superfluous phase sufficiently in solid solution, to obtain single phase solid solution The heat treatment process of body.Main function is to obtain the structural state of single phase austenite, to guarantee that its is nonmagnetic；Simultaneously improve steel and The plasticity and toughness of alloy eliminate stress and softening, to continue to process or to form.

Seven, pre- bulging, the ring billet after solution treatment carry out bulging, bulging preheating temperature using external fluid infusion hydraulic pressure expanding device Not higher than 300 DEG C, the rate of bulging is less than 2.5mm/h, and control central diameter deflection is 6-20%, is dissolved again after pre- bulging Processing；For four kinds of retaining rings pointed in third step, pre- Bulging Process is will shield in bulging equipment (referring to Fig. 3 and Fig. 4) Ring 15 is placed on low punch 11, under upper punch 12 and pressure pad 13, constantly pushes pressure pad 13, upper punch 12 using ten thousand tons of press It is moved down along power column 14 is subtracted, forms sealing space, filled water in retaining ring by the inside fluid infusion in channel 17 using super-pressure pump Space and form high pressure, retaining ring generates uniform plastic deformation in the cold state, forms cold deformation strengthening；Cold deformation strengthening refers to Metal material under external force, has occurred the permanent irreversible transformation beyond elastic limit, leads when being lower than crystallization temperature Metal inside lattice is caused to be distorted, dislocation density increases, and make further to slide and the resistance of deformation increases, thus metal material Intensity and hardness significantly improve, the phenomenon that moulding and toughness are decreased obviously；In engineering, occur when deflection is greater than 0.2% Deformation be irreversible plastic deformation；With the continuation of pre- Bulging Process, the diameter of retaining ring constantly becomes larger, height constantly contracts Small, thickness is constantly thinned, and intensity significantly improves.

Eight, main bulging, the ring billet after pre- bulging is not higher than 300 DEG C in deformation preheating temperature, using external fluid infusion hydraulic pressure Bulging device carries out bulging, and the rate of bulging is less than 2.5mm/min, and control central diameter deflection is 32-52%.By pre- bulging Afterwards, solution treatment, deformation preheating temperature≤300 of ring billet solution treatment can be carried out to the ring billet after bulging before main bulging DEG C, it is heated up with speed not higher than 150 DEG C/h, after solid solution heat preservation (i.e. deformation preheating temperature≤300 DEG C), is come out of the stove quickly Water cooling is to being not higher than 100 DEG C of water outlets.For three kinds of retaining rings mentioned above, the size after bulging see the table below shown；

Nine, stress-removal is heat-treated, and the ring billet rate of heat addition after main bulging is not higher than 40 DEG C/h, is kept the temperature at 350-400 DEG C It 6-12 hours, is furnace-cooled at 100 DEG C and can come out of the stove with the cooling rate not higher than 20 DEG C/h, nuclear power retaining ring is made.It is answered by disappearing Power heat treatment significantly reduces residual stress, to meet product service demand.Stress-removal heat treatment is the rear supplementary processing of technique Processing step.

Specific retaining ring is needed for some, needs to carry out reaming after blank hot extrusion step, the reaming of ring billet will be hot Molding blank uses saddle forging after extruding；Ring billet size after reaming is as follows:

Retaining ring code name	Outer diameter mm	Internal diameter mm	Length mm	Weight kg
					Retaining ring A	800	520	800	1810
Retaining ring B	720	450	580	1130
					Retaining ring C	680	430	640	1080

Retaining ring B therein can not reaming.

Manufactured nuclear power should carry out every physicochemical property inspection and nondestructive testing with retaining ring, be commented with making to its performance indicator Valence.

The foregoing is merely presently preferred embodiments of the present invention, is not intended to limit the invention, it is all in spirit of the invention and Within principle, any modification, equivalent replacement, improvement and so on be should all be included in the protection scope of the present invention.

Claims (4)

1. a kind of manufacturing process of nuclear power retaining ring, which is characterized in that its processing step are as follows:

One, steel ingot is forged into bar by the upsetting pull of three fire time by forging bar；Steel ingot in the forging bar step It is 0.60-0.75% for nitrogen element content, using the steel ingot of electroslag remelting process production, diameter 600-800mm, length is not small In 1780mm, weight is 5-6 tons, and surface is without slag runner defect；

Two, bar periphery is carried out roughing and is divided into hot extrusion base then by its sawing by bar roughing, sawing Material；

Three, blank heating to temperature is 1200 DEG C ± 20 DEG C by blank hot extrusion, and soaking time is set not less than coming out of the stove after 8h In extrusion die, is persistently squeezed using press, blank is got into circle hole shape into ring billet；

Four, the machining of ring billet, size before machining ring billet to bulging by the requirement of bulging process；

Five, ring billet solution treatment will carry out solid solubility temperature heat preservation, heat preservation by mach ring billet with 1060 ± 20 DEG C of temperature Time 1-3 hours, quick water cooling later；

Six, the ring billet after solution treatment is preheating to temperature not higher than 300 DEG C in deformation by pre- bulging, swollen using external fluid infusion hydraulic pressure Shape dress sets carry out bulging, and the rate of bulging is less than 2.5mm/min, and control central diameter deflection is 6-20%；After the pre- bulging Solution heat treatment is carried out to the ring billet after pre- bulging, the solution treatment is to be heated up with speed not higher than 150 DEG C/h, After solid solution heat preservation, quick water cooling of coming out of the stove is to being not higher than 100 DEG C of water outlets；The solution treatment be with speed not higher than 150 DEG C/ H heats up, and after solid solution heat preservation, quick water cooling of coming out of the stove is to being not higher than 100 DEG C of water outlets；

Seven, main bulging, the ring billet after pre- bulging is not higher than 300 DEG C in deformation preheating temperature, using external fluid infusion hydraulic pressure expanding Device carries out bulging, and the rate of bulging is less than 2.5mm/min, and control central diameter deflection is 32-52%；The main bulging is laggard The heat treatment of row stress-removal, to be heated up with the rate of heat addition not higher than 40 DEG C/h, the ring billet after main bulging is in 350-400 DEG C of temperature Lower heat preservation keeps the temperature 6-12 hours, is furnace-cooled at 100 DEG C and is come out of the stove with the cooling rate not higher than 20 DEG C/h.

2. the manufacturing process of nuclear power retaining ring according to claim 1, which is characterized in that in the forging bar step Three fire time upsetting pull forging are as follows: by Heating Steel Ingots to 1200 ± 20 DEG C of temperature, and soaking time is not less than 8h, is forged System, the first fire time jumping-up to length are 1500-1800mm, and pulling to length is 1650-1950mm, then by Heating Steel Ingots to temperature 1200 ± 20 DEG C of degree, after soaking time is not less than 8h, the second fire time jumping-up to length is 1100-1400mm, and pulling to length is 1600-1900mm, again by Heating Steel Ingots to 1200 ± 20 DEG C of temperature, after soaking time is not less than 8h, third fire time jumping-up is extremely Length is 1000-1350mm, and pulling to diameter 700-750mm, length 1200-1600mm pulls out reduction in pass 20- 50mm；After forging three times that steel ingot is air-cooled.

3. the manufacturing process of nuclear power retaining ring according to claim 2, which is characterized in that the bar roughing, saw It cuts in step, bar periphery is subjected to roughing by 710 ± 20mm of diameter.

4. the manufacturing process of nuclear power retaining ring according to claim 3, which is characterized in that laggard in blank hot extrusion step Ring billet molding after hot extrusion is used saddle forging by the reaming of row ring billet.