CN102927552B - Shockproof strip assembly for steam generator of nuclear power unit - Google Patents

Abstract

The invention relates to a shockproof strip assembly for a steam generator of a CAP1400 unit. The shockproof strip assembly comprises a shockproof strip of a V-shaped structure and two end caps which are respectively arranged at the two ends of the shockproof strip, wherein the shockproof strip is made from 405 stainless steel material, and the end caps are made from 690 nickel-based alloy material. A method for preparing the shockproof strip assembly comprising the processes of preparation of the shockproof strip, preparation of the end caps, bending and moulding, assembling the end caps, upsetting, inspection, cleaning and packaging. The shockproof strip assembly for the steam generator of the CAP1400 unit provided by the invention is simple in structure, quality of the shockproof strip assembly meets precision requirement of the steam generator in a power nuclear unit on the shockproof strip, and the shockproof strip assembly is safe when being used. The preparation method of the shockproof strip provided by the invention is strict in processes, technological requirements on the shockproof strip assembly for the steam generator in the power nuclear unit are guaranteed, quality is guaranteed, and safety is improved.

Description

Anti-vibration strip assembly for steam generator of nuclear power unit

technical field

The invention relates to an anti-vibration bar assembly of a steam generator of a CAP1400 nuclear power unit.

Background technique

CAP1400 is the code name of the major special demonstration project of pressurized water reactor, which refers to the advanced passive nuclear power technology with an installed capacity of more than 1.4 million kilowatts in my country.

The U-shaped heat transfer tube in a nuclear power plant is the most critical and weakest link in the pressure boundary of the primary circuit system. Once the heat transfer tube is damaged by vibration, the steam generator must be replaced, which will inevitably cause a huge waste of manpower, financial resources and incidents, and also increase the risk of radioactive radiation for maintenance personnel. Therefore, solving the steam generator tube failure accident is a key issue related to the safety of the nuclear power plant and to make the nuclear power plant competitive and viable.

In order to eliminate the source of vibration as much as possible, it is generally necessary to install anti-vibration strips at the elbow of the U-shaped heat transfer tube in the steam generator. How to provide an anti-vibration strip assembly with good anti-vibration performance, which is convenient, simple, and precise The high preparation method is a technical problem in this field.

Contents of the invention

The technical problem to be solved by the present invention is to provide an anti-vibration bar assembly of a CAP1400 nuclear power unit steam generator with good anti-vibration performance.

The anti-vibration bar assembly of the steam generator of the CAP1400 unit of the present invention includes: an anti-vibration bar with a V-shaped structure and two end caps respectively fixedly sleeved on both ends of the anti-vibration bar; the section of the anti-vibration bar is rectangular, and the ends are The cross-section of the cap is zigzag, so as to facilitate the fixing of the anti-vibration bar and the end cap by upsetting.

The anti-vibration bar is made of 405 stainless steel; the end cap is made of 690 nickel-based alloy material, and the U-shaped heat transfer tube in the steam generator of the unit is also a nickel-based alloy material. The tube is secured by welding with the end cap. The 690 nickel-based alloy material also has the characteristics of strong corrosion resistance.

The end cap is fixed on the anti-vibration strip by upsetting, so as to prevent the end cap from being pulled off during the assembly and welding process of the anti-vibration strip assembly and the U-shaped pipe. During specific implementation, the center of the end cap and the parts adjacent to the two ends of the end cap on the anti-vibration strip are crushed.

A preparation method of the anti-vibration bar assembly, comprising the steps in turn:

A. The process of bending the anti-vibration bar into shape: cut the anti-vibration bar according to the total length of the required size plus 50mm allowance, bend the anti-vibration bar at a set angle, and place the bent anti-vibration bar on the Grinding the corner thickening area on the surface grinder;

B. The assembly process of the end cap: lightly scrub the surface of the end cap and the inner hole of the wire cutting with alcohol, and at the same time clean the anti-vibration bar with alcohol. After cleaning, remove burrs, bite marks, protruding metal or sharp corner; then insert the end of the anti-vibration bar into the inner hole at the cap end.

C. Upsetting process: (1) Pull-off force process evaluation: evaluate the pull-off force of the end cap after assembly and upsetting, so that the position of the cap does not move under the minimum tension; the end cap under different pressures Make a record of the pull-off force at the top of the head, and select the most suitable pressure as the pressure process parameter in the upsetting process; (2) Upsetting pressure: put the end of the cap into the upsetting mold, and use a hydraulic press to adjust the central position and resistance of the end cap respectively. The position on the vibrating bar adjacent to the two ends of the end cap is subjected to upsetting pressure, and the pressure is kept for 10 seconds after being pressed down and positioned, and then unloaded. There are four upsetting positions on the anti-vibration strip, two adjacent to the end of the end cap, which are used to limit the end of the cap and prevent the displacement of the end cap on the anti-vibration strip.

The preparation method of the anti-vibration bar rod comprises the following steps in turn:

a. Induction furnace smelting: When alloy materials are smelted, nickel plates, pure iron, and metal chromium are placed at the bottom of the induction furnace, and they are mixed and packed densely. After melting 70%, 2% of the total weight of the slag is added for steelmaking. Measured After the temperature of the molten steel reaches the tapping temperature, pour the molten steel into the ladle, calm down for 1-2 minutes, and pour it into a steel ingot bar, which effectively improves the purity and uniformity of the alloy steel, and improves the surface and internal quality of the steel ingot. Improve the performance of alloy steel.

The anti-vibration bar alloy material is required to be pure; the chemical composition is accurate and uniform; and it has a specified organizational state. There are a number of indisputable advantages to using an induction hob. Because it has no pollution sources that exist in other equipment, it can guarantee the purest metal material for carbon and other impurities; it can ensure the uniformity of the alloy because of the electrodynamic stirring of the metal pool; it can ensure that the metal is accurately obtained and maintained. The required temperature and the uniform distribution of temperature along the entire molten pool temperature; eliminate local overheating; because of its fast melting speed and less metal burning loss, it creates favorable conditions for accurately obtaining the specified alloy composition and the least element burning loss; in the improvement It is highly mobile when refining metals whose chemical composition differs from that of the forehearth.

b. Forging: Forge the steel ingot of alloy material smelted by induction furnace at 1150-1220°C for heating and heat preservation, and then forge it into a billet with a size of 50*50mm; after surface finishing and grinding, it is sent to the next step of hot rolling blank process.

Forging is a processing method that uses forging machinery to apply pressure to metal blanks to cause plastic deformation to obtain forgings with certain mechanical properties, certain shapes and sizes. Forging can eliminate defects such as loose casting of metals during the smelting process. , optimize the microstructure, and because the complete metal flow line is preserved, the mechanical properties of forgings are generally better than castings of the same material. For important parts with high loads and severe working conditions in related machinery, forgings are mostly used, except for plates, profiles or weldments that can be rolled with simpler shapes. Generally speaking, forging is the first step in material processing called "blank opening".

c. Hot-rolling: Put the steel billet with the size of 50×50mm at 1050-1100℃, heat it, keep it warm, then hot-roll it, and roll it into a bar of ф16mm.

The anti-vibration bar alloy material is forged into a steel billet with a size of 50×50mm and rolled into steel materials of various geometric cross-sectional shapes by means of heating. According to the shape of the steel section, it can be divided into three types: simple section, complex section or special-shaped section and periodic section.

(1) Hot rolling can significantly reduce energy consumption and cost. The metal has high plasticity and low deformation resistance during hot rolling, which greatly reduces the energy consumption of metal deformation.

(2) Hot rolling can improve the processing performance of metals and alloys, that is, the coarse grains in the cast state are broken, the cracks are significantly healed, the casting defects are reduced or eliminated, the cast structure is transformed into a refined deformed structure, and the processing of the alloy is improved. performance.

(3) The anti-vibration bar alloy material is rolled with a large hot-rolled ingot and a large reduction, which not only improves the production efficiency, but also creates conditions for increasing the rolling speed and realizing the continuity and automation of the rolling process.

(4) The hot rolling process actually belongs to the intermediate processing process and is an important step in forming the finished blank.

d. The first heat treatment (annealing heat treatment): In order to ensure the surface quality of the anti-vibration bar alloy material, the hot-rolled bar is subjected to surface finishing and grinding before vacuum annealing treatment. Heating and holding at ℃.

Annealing heat treatment is divided into complete annealing, incomplete annealing and stress relief annealing. The mechanical properties of annealed materials can be detected by tensile test or hardness test. Intermediate heat treatment, also called pre-heat treatment, is a heat treatment set up to eliminate the defects of the previous process or to make the subsequent process easy to process. It is a metal heat treatment process that slowly heats the metal to a certain temperature, maintains it for a sufficient time, and then cools it at an appropriate speed.

Purpose of annealing

① Improve or eliminate various structural defects and residual stresses caused by steel casting, forging, rolling and welding, and prevent deformation and cracking of workpieces.

② Soften the workpiece for cutting.

③Refine the grain and improve the structure to improve the mechanical properties of the workpiece.

④ Make organizational preparations for final heat treatment (quenching, tempering).

e. Cold drawing: softening and annealing treatment is carried out first, and the temperature is kept at 720-750°C for 40 minutes; according to the deformation requirements, the polycrystalline mold is used to draw sequentially, and the surface micro-cracks are ground, and the surface can be ground to no defects. Do the next pull.

Cold drawing is a production method in which the hot-rolled anti-vibration bar alloy bar is softened and annealed and then reprocessed in a cold state to obtain various precision and high-precision products or intermediate products.

f. The second heat treatment: Pull the bar until the finished material is laid flat in a bell-type heat treatment furnace, and carry out heat treatment under the protection of hydrogen. Cool slowly at a cooling rate of 28°C/hour to below 610°C, and then air cool to room temperature.

Metal heat treatment is one of the important processes in mechanical manufacturing. Compared with other processing techniques, heat treatment generally does not change the shape and overall chemical composition of the workpiece, but changes the microstructure inside the workpiece or changes the chemical composition of the surface of the workpiece. , to give or improve the performance of the workpiece. It is characterized by improving the intrinsic quality of the workpiece, which is generally not visible to the naked eye.

In order to make metal workpieces have the required mechanical properties, physical properties and chemical properties, in addition to reasonable selection of materials and various forming processes, heat treatment processes are often essential. Steel is the most widely used material in the machinery industry. The microstructure of steel is complex and can be controlled by heat treatment. Therefore, the heat treatment of steel is the main content of metal heat treatment. In addition, aluminum, copper, magnesium, titanium, etc. and their alloys can also change their mechanical, physical and chemical properties through heat treatment to obtain different performance.

g. Finished product processing: Straighten and polish the processed bar.

The correction of shape defects of metal plastic processing products is one of the important finishing processes. Various shape defects often occur in the production process of cold drawn materials or in the subsequent cooling and transportation processes, such as bending and wave of profile pipes , ladle bending, etc., through various straightening equipment, the defects such as bending can be eliminated under the action of external force, so that the product can reach the ideal state of qualification.

(1) Coarse grinding: In addition to making the surface smooth and flat, the polishing of the product should minimize surface damage as much as possible. Each polishing process must remove the deformed layer caused by the previous process (at least the deformed layer produced by the previous process should be reduced to the depth of the deformed layer produced by this process), rather than just remove the wear marks of the previous process; at the same time, The process itself should minimize damage to facilitate the next process. The depth of the deformed layer produced by the last polishing process should be very shallow to ensure that it can be removed in the next polishing process. Care should be taken during this process to prevent the metal from overheating.

(2) Fine grinding: The purpose of fine grinding is to eliminate the deep grinding marks left by rough grinding and lay a good foundation for the next step of polishing. Fine grinding is usually carried out on sandpaper, which is divided into water sandpaper and metallographic sandpaper. Usually water sandpaper is SiC abrasive which is insoluble in water. The abrasive of metallographic sandpaper includes artificial corundum, silicon carbide, iron oxide, etc., which are extremely hard and have polygonal edges and corners. They have good cutting performance. Water can be used as lubricant for fine grinding. Manual wet grinding or mechanical wet grinding, usually use four types of water sandpaper with a particle size of 240, 320, 400, and 600 to polish before polishing. For softer metals, use finer metallographic sandpaper to polish before polishing. The sandpaper slopes outwards and downwards (viewed from the operator’s direction). When sticking it on the flat glass for grinding, put the sample on the sandpaper and push it straight forward to leave the sandpaper. Repeat this until the old All the wear marks disappear, and new wear marks with uniform direction are obtained on the entire grinding surface. Before each sandpaper is changed, the sand particles on the sample and hands must be washed with water and dried, and then the sample is rotated 90° Sand on secondary sandpaper. During use, the flowing water continuously flows over the surface of the sandpaper, washing away most of the abrasive debris and fallen abrasive grains in time. In this way, during the entire polishing operation, the sharp edges and corners of the abrasive grains are always in contact with the surface of the sample, maintaining its good grinding effect. Another advantage of the wet grinding method is that the cooling effect of water can reduce the frictional heat generated on the surface of the sample during polishing and avoid changes in the microstructure. The whole polishing process can be completed on the same equipment.

The preparation method of the end cap includes the following steps in sequence: induction furnace smelting, forging, hot rolling, heat treatment, and end cap turning; (the function, purpose or technical effect of each process needs to be supplemented)

The induction furnace smelting: when the alloy material is smelted, a nickel plate, pure iron, and metal chromium are placed at the bottom of the induction furnace, and they are mixed and compacted. After melting 70%, 2% of the total weight of the slag is added for steelmaking, and the measured After the molten steel temperature reaches the tapping temperature, pour the molten steel into the ladle, calm down for 1-2 minutes, and pour it into steel ingots.

The anti-vibration bar alloy material is required to be pure; the chemical composition is accurate and uniform; and it has a specified organizational state. There are a number of indisputable advantages to using an induction hob. Because it has no pollution sources that exist in other equipment, it can guarantee the purest metal material for carbon and other impurities; it can ensure the uniformity of the alloy because of the electrodynamic stirring of the metal pool; it can ensure that the metal is accurately obtained and maintained. The required temperature and the uniform distribution of temperature along the entire molten pool temperature; eliminate local overheating; because of its fast melting speed and less metal burning loss, it creates favorable conditions for accurately obtaining the specified alloy composition and the least element burning loss; in the improvement It is highly mobile when refining metals whose chemical composition differs from that of the forehearth.

The forging: the ingot of the anti-vibration bar alloy material smelted by the induction furnace is heated and kept at 1150-1220°C and then forged into a steel billet with a size of 50*50mm; after the surface is finished and ground, it is sent to the next step of hot rolling blank process .

Forging is a processing method that uses forging machinery to apply pressure to metal blanks to cause plastic deformation to obtain forgings with certain mechanical properties, certain shapes and sizes. Forging can eliminate defects such as loose casting of metals during the smelting process. , optimize the microstructure, and because the complete metal flow line is preserved, the mechanical properties of forgings are generally better than castings of the same material. For important parts with high loads and severe working conditions in related machinery, forgings are mostly used, except for plates, profiles or weldments that can be rolled with simpler shapes. Generally speaking, forging is the first step in material processing called "blank opening".

The hot rolling: the steel billet with the size of 50×50 mm is heated at 1200±10° C., heat-preserved, and then hot-rolled to form a bar of ф13×25 mm.

The anti-vibration bar alloy material is forged into a billet with a size of 50×50mm, and the billet is rolled into various geometric cross-sectional shapes by heating. According to the shape of the steel section, it can be divided into three types: simple section, complex section or special-shaped section and periodic section.

(1) Hot rolling can significantly reduce energy consumption and cost. The metal has high plasticity and low deformation resistance during hot rolling, which greatly reduces the energy consumption of metal deformation.

(2) Hot rolling can improve the processing performance of metals and alloys, that is, the coarse grains in the cast state are broken, the cracks are significantly healed, the casting defects are reduced or eliminated, the cast structure is transformed into a refined deformed structure, and the processing of the alloy is improved. performance.

(3) The anti-vibration bar alloy material is rolled with a large hot-rolled ingot and a large reduction, which not only improves the production efficiency, but also creates conditions for increasing the rolling speed and realizing the continuity and automation of the rolling process.

(4) The hot rolling process actually belongs to the intermediate processing process and is an important step in forming the finished blank.

The sequence of heat treatment includes: (1) solution treatment: laying the hot-rolled end cap material 13*25mm flat in a bell-type hydrogen protection furnace for solution treatment; (2) aging treatment: solution treatment The final bar is also placed in a hydrogen protection furnace for aging treatment.

Solid solution treatment is to dissolve the carbides in the matrix and γ' to be equal to obtain a uniform supersaturated solid solution, which facilitates the re-precipitation of fine, uniformly distributed carbides and γ' and other strengthening phases during aging, and at the same time eliminates due to hot and cold processing. Stress causes the alloy to recrystallize. Secondly, the solution treatment is to obtain a suitable grain size to ensure the high temperature creep resistance of the alloy. The temperature range of solid solution treatment is about 980-1250°C, which is mainly selected according to the phase precipitation and dissolution rules in each alloy and the requirements of use, so as to ensure the necessary precipitation conditions and a certain grain size of the main strengthening phase. For alloys used at high temperature for a long time, better high temperature durability and creep properties are required, and a higher solution temperature should be selected to obtain a larger grain size; for medium temperature use, better room temperature hardness, yield strength, For alloys with tensile strength, impact toughness and fatigue strength, a lower solution temperature can be used to ensure a smaller grain size. During high-temperature solution treatment, various precipitated phases are gradually dissolved, and at the same time, the grains grow; during low-temperature solution treatment, not only the main strengthening phase dissolves, but also some phases may precipitate. For alloys with low supersaturation, a faster cooling rate is usually selected; for alloys with high supersaturation, cooling in air is usually used.

Aging treatment: refers to the heat treatment process in which the alloy workpiece is subjected to solution treatment, cold plastic deformation or casting, forging, and then placed at a higher temperature or at room temperature to maintain its performance, shape, and size over time. If the aging treatment process of heating the workpiece to a higher temperature and aging treatment for a shorter period of time is adopted, it is called artificial aging treatment. If the aging phenomenon occurs when the workpiece is placed at room temperature or under natural conditions for a long time, it is called natural aging treatment. aging treatment. The third method is that vibration aging has gradually entered the practical stage since the early 1980s. Vibration aging treatment uses vibration at a certain frequency to release the internal stress without heating and is not as time-consuming as natural aging. In order to achieve the purpose of timeliness. The purpose of aging treatment is to eliminate the internal stress of the workpiece, stabilize the structure and size, and improve the mechanical properties.

In mechanical production, in order to stabilize the size of castings, castings are often placed at room temperature for a long time before cutting. This measure is also known as statute of limitations. But this aging does not belong to the metal heat treatment process.

The end cap turning process: the 13*25mm material after aging treatment is turned into an end cap of required size.

The technical effect of the present invention: the anti-vibration bar assembly of the steam generator of the CAP1400 unit described in the present invention has a simple structure, and the product quality meets the precision requirements for the anti-vibration bar of the steam generator in a nuclear power plant, and is safer to use. The preparation method of the anti-vibration strip, through strict preparation procedures, ensures the technical requirements for the anti-vibration strip assembly of the steam generator in the nuclear power plant, ensures the quality, and improves the safety. The end cap is fixed on the anti-vibration strip by upsetting, so as to prevent the end cap from being pulled off during the assembly and welding process of the anti-vibration strip assembly and the U-shaped pipe. During specific implementation, the center of the end cap and the parts adjacent to the two ends of the end cap on the anti-vibration strip are crushed.

Description of drawings

Fig. 1 is the structural representation of the anti-vibration strip assembly of the CAP1400 unit steam generator of the present invention, reference numerals: 1 - anti-vibration strip, 2 - end cap;

Fig. 2 is the top view of Fig. 1;

FIG. 3 is a cross-sectional view of an end cap in the anti-vibration bar assembly of FIG. 1 .

Detailed ways

Example 1

As shown in Figure 1, the anti-vibration bar assembly of the steam generator of the CAP1400 unit steam generator of this embodiment includes: an anti-vibration bar 1 of V-shaped structure and two end caps 2 fixedly sleeved at both ends of the anti-vibration bar; The cross-section of the bar is rectangular, and the cross-section of the end cap is zigzag, so as to facilitate the fixing of the anti-vibration bar and the end cap by upsetting.

The anti-vibration bar 1 is made of 405 stainless steel (SA-479TYPE405); the end cap 2 is made of 690 nickel-based alloy (SB-166UNS N06690).

The center of the end cap 2 and four places on the anti-vibration bar 1 adjacent to the two ends of the end cap are crushed. The two flattened places at the ends of the end caps on the anti-vibration strip 1 are distributed symmetrically.

The preparation method of the above-mentioned anti-vibration bar assembly includes: preparation of anti-vibration bar bar, preparation of end cap, bending and forming of anti-vibration bar bar, end cap assembly, upsetting, inspection, cleaning and packaging.

The anti-vibration bar is bent and formed: the anti-vibration bar is cut according to the total length of the required size plus 50mm allowance, the angle is set to bend the anti-vibration bar, and the bent anti-vibration bar is placed on a surface grinder Above, grind the thickened area of the corner to meet the requirements of the drawing.

The end cap assembly: lightly scrub the surface of the end cap and the inner hole formed by wire cutting with alcohol, and at the same time clean the anti-vibration bar with alcohol. After cleaning, remove burrs, bite marks, protruding metal or Sharp corner; then insert the anti-vibration strip bar into the cap end, align the angle for assembly.

The upsetting pressure includes: (1) Pull-off force process evaluation: evaluate the pull-off force of the end cap after assembly and upsetting, so that the position of the sleeve cap does not move under the minimum pulling force of 4448N; Make a record of the pull-off force of the end cap, select the most suitable pressure as the pressure process parameter in the upsetting process; (2) Upsetting pressure: put the end of the cap into the upsetting mold, and use a hydraulic press to align the central position of the end cap respectively And the position on the anti-vibration bar adjacent to the two ends of the end cap is upsetting. After pressing down and positioning, keep the pressure for 10 seconds and then unload to ensure that the cap end meets the requirements of the drawing after upsetting. There are four upsetting positions on the anti-vibration strip, two adjacent to the end of the end cap, which are used to limit the end of the cap and prevent the displacement of the end cap on the anti-vibration strip.

The inspection: (1) Flatness inspection, measure with feeler gauge on the inspection platform; (2) Dimension inspection, use digital display micrometer to measure the product; (3) Angle inspection, use digital display angle measuring instrument to measure; (4) Visual inspection, visual inspection of workpieces one by one to ensure that there are no defects on the surface, and the surface roughness is measured by crawling with a roughness measuring instrument; (5) Surface roughness measurement is measured with a roughness detector or a comparison sample; All dimensional inspection results shall comply with the drawing requirements.

Said cleaning: clean the bar according to the relevant regulations to ensure that the surface of the finished product is free from rust, dust and other pollutants, (1) sulfur, lead, mercury, cadmium and other metals with low melting points, as well as their alloys and compounds, containing Halogen substances are prohibited from being used in the preparation, testing, inspection and packaging of anti-vibration strips; (2) lubricants, cutting fluids and cleaning agents do not contain the above substances; molybdenum disulfide lubricants, polytetrachlorethylene and other Polyfluorinated materials are also prohibited.

Example 2

The preparation method of the anti-vibration bar in the above-mentioned embodiment 1 includes the following steps in sequence: induction furnace smelting, smelting analysis, forging, hot rolling, first heat treatment, performance test (tensile, hardness) and metallographic inspection, product Analysis, cold drawing, second heat treatment, finished product processing, performance testing (tensile, hardness) and grain size inspection, dimensional inspection, marking, cleaning.

The induction furnace smelting: when the alloy material is smelted, a nickel plate, pure iron, and metal chromium are placed at the bottom of the induction furnace, and they are mixed and compacted. After melting 70%, 2% of the total weight of the slag is added for steelmaking. After the molten steel temperature reaches the tapping temperature, pour the molten steel into the ladle, calm down for 1-2 minutes, and pour it into steel ingots and bars. The weight of each ingot is 40-50kg, the diameter of the steel ingot is 140mm for the small end and 155mm for the large end.

The smelting analysis includes: (1) Sampling: turning or planing samples for chemical analysis outside the range of 20mm from the ingot head and ingot tail; (2) Taking a chemical analysis sample for each furnace number to determine the chemical composition of each furnace steel, And filter according to content standard data. The melting chemical composition should meet the requirements of the following table:

Described forging: forge the steel ingot after the analysis is qualified at 1150-1220 ℃ to the steel billet of 50*50mm size;

(1) Forging heating thermometer:

(2) Forging: forging compression ratio: 4-6; forging size: 50*50mm; billet big head cut off more than 100mm, small head cut off more than 50mm; Surface defects such as heavy skin.

The hot rolling: put the steel billet at a temperature of 1050-1100°C for hot rolling, and roll it into a bar of ф16mm. Polished clean;

(1) Billet heating temperature table is as follows:

(2) Rolling: The adjustment worker should straighten the appearance of the rolled product, and roll it into a ф16mm wire; after the rolled product is cooled, it is necessary to check the surface quality of cracks, folds, scars, and inclusions one by one, and thoroughly polish it. ;Rolling ratio: ≥5.

The first heat treatment: vacuum annealing is performed on the hot-rolled bar, and the temperature is kept at 800±10°C;

The performance test includes: (1) randomly taking a group of samples for each batch number of hot-rolled bars after heat treatment; (2) conducting tensile test, hardness test, metallographic analysis and product analysis on the samples respectively, Exclude unqualified products;

1. The tensile test results should meet the requirements of the following table:

performance room temperature 350°C Specified strength Rp0.2(Mpa) ≥170 ≥145 Tensile strength Rm(Mpa) ≥415 ≥370 Elongation after break A (%) ≥20 info Reduction of area Z (%) ≥45 info

When the bar is ≤25mm, the longitudinal axis of the sample is consistent with the center of the bar, and the distance between the useful part of the sample and the heat-treated end of the bar must not be less than the diameter of the bar.

2. Hardness test should meet:

performance room temperature Hardness (HB) ≤207

The hardness test shall check the hardness of the bar at the middle part of the distance from the center of the bar to the surface.

3. Metallographic analysis should meet:

4. Product analysis: samples are taken from both ends of the tensile sample for material product analysis, and the analysis results should comply with:

5. Retest and reheat treatment:

5.1 If the tensile test results of the bar do not meet the requirements, two additional samples can be cut from the adjacent parts of the unqualified sample for tensile test, and the acceptance can only be accepted when the test results of the two additional samples meet the requirements;

5.2 If the mechanical properties of any batch of rods are unqualified due to improper heat treatment, the batch of materials can be re-heat treated, but the number of re-heat treatments should not exceed two times; Inspection (except inspection of chemical composition and non-metallic inclusions); all inspections shall meet the requirements of this technical condition.

The cold drawing includes: (1) softening and annealing treatment first, and heat preservation at a temperature of 720-750 ° C for 40 minutes; (2) drawing in sequence with a polycrystalline mold according to the deformation requirements, and grinding the micro-cracks on the surface , After grinding to no defect, the next drawing can be carried out.

The drawing deformation during cold drawing is φ16→φ14→φ12.5→φ11→4.8×12.8→4.4×12.5→4.028×12.19.

The softening annealing treatment system is as follows:

steel type Specification Heating temperature °C Holding time (minutes) cooling method

SA-479TYPE405 Before each cold drawing 720-750℃ ≥40 air cooling

The second heat treatment: spread the finished material in a bell-type heat treatment furnace, and conduct heat treatment under hydrogen protection. The annealing temperature is 788-815°C. The heat treatment temperature and other requirements are as follows:

The processing of the finished product: perform cold processing such as straightening and polishing on the heat-treated bar, and the thickness, width, twist, straightness and other dimensions after processing should meet the requirements of the following table:

The performance test: perform mechanical property test, hardness test, and grain size inspection on the rods, and exclude the rods that do not meet the technical requirements.

1. The mechanical performance test shall comply with:

performance room temperature Specified strength Rp0.2(Mpa) 240-550 Tensile strength Rm(Mpa) 415-585 Elongation after break A (%) ≥15

2. Hardness test should meet:

performance room temperature hardness HB≤207 or HRB≤93

3. Grain size inspection:

Testing method level requirements ASTM E112 Grade 5 or finer

If the mechanical properties of the bar do not meet the technical requirements, double samples can be taken from the adjacent part of the sample for retesting, and the retesting results should meet the technical requirements.

The dimensional inspection includes: (1) Visual inspection: visually inspect the surface of each material one by one to ensure that there are no cracks, scratches and other defects. No welding repair is allowed for the rods, and the surface roughness of the rods shall be inspected one by one. (2) Dimensional inspection: Take 5% of the material for size inspection to ensure that the material size meets the tolerance requirements of 4.028±0.013*(12.19).

The above-mentioned marks: each material should be accurately marked or attached with a label, indicating the name of the manufacturer, material grade and specification; melting furnace number, batch number and part number; contract number or order number.

Cleaning as described: Clean the bar according to the relevant regulations to ensure that the surface of the finished bar is free from rust, dust and other pollutants; the steel bar cannot touch materials that are harmful to it and its integrity. The main metal incompatible materials are lead, zinc, copper, aluminum, cadmium, tin, mercury, sulfur, arsenic, boron and general low melting point alloys and their compounds. Fluorides, sulfates, chlorides, and acidic chlorides from degradation are a potential hazard and tapes, markers, couplants, penetrants, and coatings should be carefully selected; if abrasive tools are to be used, first ensure that the abrasive tools Not polluted.

Example 3

The preparation method of the end cap in the above-mentioned embodiment 1 includes the following steps in sequence: induction furnace smelting, electroslag refining, smelting analysis, forging, ultrasonic inspection, hot rolling, heat treatment, performance test, product analysis, end cap car processing, size Inspect, mark, clean.

The induction furnace smelting: when the alloy material is smelted, a nickel plate, pure iron, and metal chromium are placed at the bottom of the induction furnace, and they are mixed and compacted. After melting 70%, 2% of the total slag is added for steelmaking, and the measured After the temperature of the molten steel reaches the tapping temperature, pour the molten steel into the ladle, calm down for 1-2 minutes, and pour it into steel ingots and bars. The weight of each ingot is 40-50kg.

The electroslag refining: After the alloy material is smelted, electroslag refining is required to effectively improve the purity and uniformity of the alloy steel, improve the surface and internal quality of the steel ingot, and improve the performance of the alloy steel. When the electroslag refining is completed, feed shrinkage, after feeding for 3-5 minutes, cool for ≥ 3 minutes to take off the ingot. Then carry out electroslag ingot surface treatment: surface peeling and grinding.

The smelting analysis described includes: (1) Sampling: Carrying or planing chemical analysis samples outside the range of 20mm from the ingot head and ingot tail; (2) Take a chemical analysis sample for each furnace number, according to ASTM E38 nickel-chromium According to the test method required by "Chemical Analysis Method of Nickel-Chromium-Fe Alloy" to analyze the chemical composition of the material, and screen according to the content standard data, the smelting chemistry should meet:

element Composition Limit % element Composition Limit % element Composition Limit % element Composition Limit % Ni 58.0min Cr 27.0-31.0 Fe 7.0-11.0 mn 0.5max Si 0.5max C 0.015-0.030 al 0.50max Ti 0.50max B 0.005max N 0.05max S 0.010max P 0.015max Cu 0.20max Nb 0.10max Mo 0.10max co 0.05max Mg info Ta info

The forging: forge the steel ingot that has passed the analysis at a temperature of 1240-1260° C. to form a steel billet with a size of 50*50 mm.

1. The steel ingot should be annealed before forging, and the heat treatment temperature should be as follows:

2. Deformation process: forging compression ratio: 4-6; billet big head cut off more than 100mm, small head cut off more than 50mm; forged billet size is 50*50mm; Surface defects such as wrinkles, cracks and heavy skin.

Ultrasonic inspection: Ultrasonic inspection is carried out on the stripped and ground square bar according to the detection method and acceptance criteria stipulated in the "Technical Conditions for Nondestructive Testing of Bars".

The hot rolling: the billet is placed at a temperature of about 1200°C for hot rolling, and rolled into a material of 13*25mm. The deviation of the hot rolling temperature does not exceed 10 degrees. After the hot rolling is cooled, the cracks of the surface quality should be inspected one by one. , folds, scars, inclusions and other defects, and thoroughly polished;

1. The forged billet is annealed before hot rolling, and the annealing temperature is as follows:

2. Rolling control: Roll the end cap material to 13*25mm; after the rolled products are cooled, inspect the surface cracks, folds, scars, inclusions and other defects one by one, and cut off or thoroughly polish them; the rolling ratio is ≥5.

The heat treatment includes: 1. Solution treatment: lay the hot-rolled end cap material 13*25mm flat in a bell-type hydrogen protection furnace for solution treatment, and the heat treatment temperature is as follows:

steel type Specification Heating temperature °C Holding time (h) cooling method

SB-166UNS N06690 13*25mm The specific heat treatment temperature is as follows ≥1 air cooling

Carbon contentwt.% Minimum holding temperature ℃ 0.015 1016 0.016 1023 0.017 1030 0.018 1036 0.019 1043 0.020 1049 0.021 1055 0.022 1060 0.023 1066 0.024 1071 0.025 1076 0.026 1081 0.027 1085 0.028 1090 0.029 1094 0.030 1099

Among them, the insulation temperature deviation does not exceed ±10°C.

2. Aging treatment: The bars after solid solution treatment must be subjected to aging treatment, and the aging treatment should also be carried out in a hydrogen protection furnace. The heat treatment temperature is:

steel type Specification Heating temperature °C Holding time (h) cooling method SB-166UNS N06690 13*25mm 704～732℃ 8-12h air cooling

Among them, the temperature deviation of the aging treatment during the holding period should not exceed ±10°C.

3. The solid solution and aging heat treatment records should be included in the quality certification documents, and the heat treatment records should include the holding temperature and its deviation, holding time, heating rate, heating atmosphere and cooling method.

The performance tests described include:

1. Sampling: Randomly take a sample for each heat batch number for mechanical performance test, the longitudinal axis of the tensile sample is parallel to the axial direction of the bar. The useful part of the tensile test piece is separated from the end of the bar by at least one bar diameter; the longitudinal axis of the tensile test piece is located at the center of the bar; the test piece has sufficient length to intercept the hardness test piece, Metallographic samples and all test quantities and samples required for possible retests.

2. Tensile test should meet:

Among them, the tensile test uses a standard sample with a gauge length of 50 mm and a diameter of 12.5 mm.

3. Metallographic analysis: Take a sample near the sample for the tensile test for metallographic analysis. The detection standard for metallographic analysis is:

4. Macroscopic erosion test: One piece of each batch is selected for macroscopic erosion test. The test should be carried out on the cross-section of the cut head at both ends of the bar, and evaluated with the naked eye or with a magnifying glass below 10 times. No shrinkage cavity, Defects such as voids, cracks, slag inclusions and pinholes.

5. Intergranular corrosion test: For each batch of bars, a group (two) samples should be taken from any bar after aging treatment for intergranular corrosion test. After sensitization treatment, the sensitization treatment system is 675°C±5°C for 1 hour, and the corrosion rate of the sample should be less than 20mdd (mg/square decimeter.day).

6. Product analysis: Take a sample from each furnace near the tensile sample for product analysis of the material, and the product analysis results should meet:

element Composition Limit % element Composition Limit % element Composition Limit % element Composition Limit % Ni 58.0min Cr 27.0-31.0 Fe 7.0-11.0 mn 0.5max Si 0.5max C 0.015-0.030 al 0.50max Ti 0.50max B 0.005max N 0.05max S 0.010max P 0.015max Cu 0.20max Nb 0.10max Mo 0.10max co 0.05max Mg info Ta info

The end cap turning process: conduct a performance test on the 13*25mm material after aging treatment, and turn the qualified material into an end cap product with a diameter of 22.86±0.05 and a length of 50.8±0.07 as required.

The dimensional inspection: 1. Visually inspect the surface of each material one by one, and the end caps are not allowed to have nicks, burrs, longitudinal cracks, and metal bulges. 2. Check the size of the material, and the inspection quantity of each furnace material should be greater than 5%.

The above-mentioned marks: each material should be accurately marked or attached with a label, which should include: order number, material grade and specification, bar part number, melting furnace number, heat treatment furnace number, and the name of the bar manufacturer.

Cleaning as described: Clean the bar according to relevant regulations to ensure that the surface of the finished end cap is free from rust, dust and other pollutants.

Claims (1)

1. a preparation method for the antivibration bar assembly of CAP1400 nuclear power generating sets steam generator, is characterized in that described antivibration bar assembly comprises: the antivibration bar of V font structure and respectively fixed cover are located at the end cap at antivibration bar two ends; The cross section of antivibration bar is rectangular, and the cross section of end cap is three-back-shaped; Described end cap upsetting pressure is fixed on described antivibration bar;

Described antivibration bar is selected 405 stainless steel materials; Described end cap is selected 690 nickel-bass alloy materials;

The preparation method of above-mentioned antivibration bar assembly, in turn includes the following steps:

A, antivibration bar bar is bent to the operation of moulding: by antivibration bar bar on request size overall length add 50mm allowance and cut off, set angle bends antivibration bar, the antivibration bar after bending is placed on surface grinding machine, and bent angle buildup area is carried out to reconditioning;

The operation of B, end cap assembling: end cap is dabbed and washes end cap surface and line cutting endoporus with alcohol, with alcohol, antivibration bar bar is cleaned simultaneously, after cleaning up, deburring, bite mark, protrusion metal or wedge angle; Again the end of antivibration bar bar is inserted in the endoporus of cap end;

The operation of C, upsetting pressure: cap end is put into upsetting pressure mould, with hydraulic press respectively four points at each two places, contiguous end cap two ends on the middle position to end cap and antivibration bar carry out upsetting pressure, keep pressure off-load after 10 seconds after depressing location;

The preparation method of described antivibration bar bar in turn includes the following steps:

A, induction furnace are smelted: when alloy material is smelted, place nickel plate, pure iron, crome metal in induction furnace bottom, and load in mixture closely knit, after fusing 70%, add 2% slag charge of the weight that always feeds intake to make steel, record after molten steel temperature reaches tapping temperature molten steel to fall down in ladle, after calm 1-2 minute, pour into steel ingot bar;

B, forging: the alloy material steel ingot after smelting by induction furnace is forged into the steel billet of 50*50mm size after 1150-1220 DEG C of heating and insulation, and carries out surface finish reconditioning;

C, hot rolling: by the steel billet of 50 × 50mm size, carry out hot rolling after being placed at 1050-1100 DEG C of temperature heating, insulation, be rolled into the bar of ф 16mm;

D, the first heat treatment: for the surface quality that the ensures antivibration bar alloy material bar after to hot rolling carries out carrying out vacuum annealing processing after surface finish, reconditioning again, φ 16mm bar heats, is incubated at 800 DEG C ± 10 DEG C of temperature;

E, cold-drawn: first carry out soft annealing processing, at 720-750 DEG C of temperature, be incubated 40 minutes; By glomerocryst mould drawing successively for deformation requirements, and effects on surface micro-crack place carries out reconditioning, and reconditioning can be carried out the drawing of lower road to zero defect;

F, the second heat treatment: bar is pulled to finished-product material and is laid in bell-jar heat-treatment furnace, under hydrogen shield state, heat-treat, between annealing soak, temperature is 788-815 DEG C, and insulation is more than 3 hours; Then to be no more than below 28 DEG C/h of cooling velocity slow cooling to 610 DEG C, then air cooling is to room temperature;

G, finished product processing: bar after treatment is aligned, polished.