CN110940545B - A sampling method for quality inspection of penetrating piece heads - Google Patents

Abstract

The invention relates to a sampling method for quality inspection of a penetrating piece head. The penetrating piece head includes a head body and a penetrating body. The sampling object of the sampling method is the blank piece of the penetrating piece head with a margin. Sampling is carried out after heat treatment, and the sampling method includes the following steps: ①. Cutting the first ring-shaped test piece on the head body, and dividing the cut first ring-shaped test piece into a plurality of first sample blocks; ②. Cut the second ring-shaped test piece on the body, and divide the cut-off second ring-shaped test piece into a plurality of second sample blocks; take samples from both the penetrating body and the head body, so as to make more changes on the whole penetrating piece head. In order to complete and comprehensive quality analysis, the overall quality of the mechanical penetration head of the main steam system is fully inspected through the analysis of the physical and chemical properties of the sample, and it is not necessary to completely destroy the penetration head, and it can still be obtained after sampling. Continued use as a product minimizes sampling costs.

Description

A sampling method for quality inspection of penetrating piece heads

technical field

The invention relates to a sampling method for quality inspection of a penetrating piece head.

Background technique

As the concept of low-carbon environmental protection is becoming more and more popular, nuclear power, a clean energy source, has attracted more and more attention from all countries. my country has carried out localization of nuclear power equipment since the end of the last century, and the main equipment of the nuclear island of the second-generation nuclear power plant reactor has been fully localized. The main equipment of the third-generation nuclear power and Hualong No. 1 nuclear power unit with independent intellectual property rights Nationalization stage. With the improvement of the power of the new reactor type and the latest requirements of nuclear safety, the design of the important components of the nuclear island is also developing in the direction of large-scale and integrated, resulting in the design of some forgings changing from the usual regular shape to one with steps, variable diameters, seals, etc. The first-class irregular shape is restricted by the current manufacturing technology conditions, especially for forgings manufactured by free forging, it is impossible to ensure that the structure and performance of all parts of the forging are consistent. In actual production, especially in the manufacturing process of the main equipment of the nuclear island, due to the inconsistent wall thickness of forgings, problems such as coarse grains in different parts of the workpiece, and mechanical performance indicators that do not meet the requirements often occur. This results in subsequent reheat treatment or direct scrapping of components, which increases manufacturing costs and affects the construction period of nuclear power plants. In addition, since there is no better performance verification method for the part with the largest wall thickness in addition to a comprehensive dissection of the sampling part of the acceptance test of the current component, there may also be certain safety hazards during the service period of the equipment. Therefore, to achieve mass production under the condition of quality assurance, not only the manufacturer needs to innovate in manufacturing technology, but also needs to carry out a targeted quality inspection plan for forgings.

The main steam system of nuclear island is an important part of the safe operation system of nuclear power. These parts need to be in direct contact with high temperature steam during operation. The operating conditions are harsh (about 300°C, 16MPa high-temperature and high-pressure water containing phosphoric acid and boric acid), and the requirements for material properties are extremely high. In addition to good comprehensive mechanical properties (sufficient strength, high plasticity and toughness), resistance to High temperature and high pressure water corrosion, good fatigue resistance, easy processing and welding performance, etc. In order to ensure the safety of nuclear power plants and further improve the operating life of nuclear power plants, higher requirements are put forward for the quality of these important components of nuclear islands in the production and manufacture of raw materials (nuclear safety level 1, quality assurance level QI level, earthquake resistance category I level, Cleaning category A, welding seam level is 1), with the characteristics of high manufacturing technical standards, high difficulty and long cycle.

At present, most of the nuclear power plants in commercial operation and under construction in the world are manufactured in accordance with the RCC-M "Rules for the Design and Construction of Pressurized Water Reactor Mechanical Equipment" formulated by the French Nuclear Island Equipment Design and Construction Committee (AFCEN) and the American ASME standard. The main equipment of the nuclear island adopts the forging process, which has uniform structure and good mechanical properties. However, due to the limitation of the manufacturing process, the forging ratio of each part of the main equipment of the nuclear island, especially some special-shaped parts, is different during the forging process. Failure to reach the predetermined target will cause deviations in the final mechanical performance indicators and affect the use.

In addition, for the procurement technical requirements of the mechanical penetration parts of the main steam system, the requirements for chemical composition, the content of main elements in the ladle C: ≤0.20%, Mn: 0.8-1.6%, P≤0.02%, S≤0.015%, Si:0.1-0.35%, Cr≤0.25%, Ni:≤0.5%, Mo:≤0.1%, Cu≤0.25%. Low melting point materials such as Pb, Zn, Cd, Hg, Bi, Tm cannot be added to the raw materials. After electric arc furnace and ladle refining, microalloy elements and impurity content are controlled to obtain molten steel with qualified composition, and then vacuum poured and then forged. In addition, the specification also makes clear requirements on the final performance indicators of materials, such as room temperature tensile (Rp0.2≥275MPa, Rm470-570MPa, A%≥21%), 300℃ high temperature tensile (Rp0. , Rm≥423MPa), KV impact (≥60J), grain size ≥5 grades, non-metallic inclusions ≤2 grades, hardness difference of each point ≤30HB, etc.

In the normal production process, problems such as inconsistency in the grain size of different parts of the structure and large differences in mechanical properties should be avoided as much as possible. Various influencing factors and control measures in the manufacturing stage must be fully considered before the manufacturing process begins, and a suitable method must be designed. Quality inspection method for forgings of mechanical penetrations in main steam systems. To achieve mass production under the condition of quality assurance, not only the manufacturer needs to innovate in manufacturing technology, but also needs to successfully complete the technical evaluation. Of course, the process evaluation of the mechanical penetration head of the main steam system must also be carried out.

The assessment itself is a comprehensive multidisciplinary nuclear power general technology, and it is also one of the core technologies of nuclear power autonomy. It involves many disciplines such as manufacturing process technology, metal materials, physical and chemical testing, non-destructive testing, design analysis, fracture mechanics, life management, and engineering management. Through equipment manufacturing process evaluation, to verify the manufacturer's manufacturing capabilities and management capabilities, and The overall and intrinsic quality of these parts or products manufactured by the manufacturer meets the requirements of design and nuclear safety, ensures the repeatability of manufacturing quality, effectively reduces inspection items, reduces manufacturing costs and shortens the manufacturing cycle, thereby providing mass production for manufacturers Important components of the nuclear island provide favorable conditions.

The mechanical penetration of the main steam system is an important part of the PWR nuclear power plant. It is located between the containment vessel and the conventional island building. It transports the steam generated by the steam generator to the steam turbine for work. As an important part connecting the containment vessel with the outside world, it is very important to the safe operation of the PWR nuclear power plant, and it must be absolutely safe and reliable during its service life. Main steam system mechanical penetrating parts specification level I, safety level I, quality level Q1, anti-seismic category I, cleanliness category A.

The mechanical penetration head of the main steam system is the key forging of the main steam system. Because of its large size, steel ingots of more than 50 tons or more than 100 tons of steel ingots (one ingot and two pieces) are generally used for forging. The smelting of steel ingots is very difficult. The head part is thicker, and it is easy to produce tensile stress during the forging process due to the difference in forging ratio with the connection part. Heat treatment parameters are not easy to choose, and the production cycle is long. The specific manufacturing process is complicated, and the manufacturing difficulties include: adopting electric arc furnace rough smelting + ladle refining molten steel, it is a very complicated technical problem to minimize segregation of steel ingots, refine grains, and reduce inclusions; forging In the process, in the upsetting and elongating process, there are ring-shaped steps that are difficult to deform, and inclusion cracks are easy to occur. When the inclusion cracks gather together, they will often show excessive defects during ultrasonic testing; during the heat treatment process, due to the large difference in the wall thickness of the forging during the quenching process, the heat exchange of each part is inconsistent, which will affect the mechanical properties; the heat treatment process is prone to deformation , the thickness of the forging is uneven, it is not easy to harden, and the cooling rate is too fast, there will be a tendency to quench cracking; the overall quality of the forging is not easy to check, and it is difficult to sample from non-standard sampling parts; it is a special-shaped part, and it is difficult to perform machining and non-destructive testing.

Due to the above-mentioned manufacturing difficulties of the mechanical penetration forgings of the main steam system, it is difficult to ensure consistent performance of each part of the forgings, and local parts are prone to damage. How to sample the penetration head forgings to test the overall quality of the forgings will also be very important. . Since the manufacturing cost of the penetration head is very high, it is impossible to thoroughly inspect each penetration head in the normal production process. It is necessary to fully consider various manufacturing factors and service conditions in the process of process evaluation, and design both A sampling method that can fully inspect the overall quality of forgings and minimize inspection costs.

Contents of the invention

The object of the present invention is to provide a sampling method for the quality inspection of the penetrating piece head in order to overcome the deficiencies of the prior art.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A sampling method for the quality inspection of the penetration head. The penetration head includes a head body and a penetration body. The sampling object of the sampling method is the blank of the penetration head with a margin, and the heat treatment of the blank is carried out. Sampling, the sampling method includes the following steps: ①, intercepting the first annular test piece on the head body, and dividing the intercepted first annular test piece into a plurality of first sample blocks; ②, intercepting on the penetrating body The second ring-shaped test piece, and the cut-off second ring-shaped test piece is divided into a plurality of second sample blocks; after the first ring-shaped test piece in step 1. is divided, at least obtain for carrying out the tensile test at room temperature The first sample block for tensile test at 300°C~400°C high temperature, the first sample block for chemical composition analysis, the first test block for metallographic examination Sample block, the first sample block used for impact test; the second ring-shaped test piece in step ② is divided to obtain at least the second sample block for tensile test at room temperature, for use at 300 ° C The second sample block for tensile test at ~400℃ high temperature, the second sample block for chemical composition analysis, the second sample block for metallographic inspection, the second test block for impact test sample block.

Preferably, there are four first ring-shaped test pieces, and the four first ring-shaped test pieces are respectively cut from both ends of the head body and the bottoms of the dimples on both sides of the head body.

Preferably, there are two second ring-shaped test pieces, and the two second ring-shaped test pieces are respectively cut from both ends of the through-body.

Preferably, the method for cutting the first sample block in step ① includes: dividing it along the circumferential direction of the first annular test piece, and dividing a plurality of first sample sections, and then dividing each first sample section The division is performed, and each first sample segment after division can obtain multiple first sample blocks.

Preferably, the method for cutting the first sample block in step ① further includes: dividing the first sample section along the radial direction of the first annular test piece, and dividing it into a plurality of first sample layers, and then dividing each The first sample layer is divided, and each first sample layer after division can obtain a plurality of first sample blocks. The circumferential direction is the same.

Preferably, each of the four first annular test pieces is divided into two first sample sections, and the two first sample sections are cut from corresponding two sides in the circumferential direction of the first annular test piece.

Preferably, the two first ring-shaped test pieces cut from both ends of the head body, the position where the first sample section is cut from one of the first ring-shaped test pieces is the same as the position where the first sample section is cut from the other first ring-shaped test piece. The positions of the sample sections are staggered in the circumferential direction.

Preferably, two first ring-shaped test pieces are cut from the bottom of the grooves on both sides of the head body, and the cutting position of the first sample section on one of the first ring-shaped test pieces is the same as that of the other first ring-shaped test piece. The position of the first sample section on the piece is staggered in the circumferential direction.

Preferably, the intercepting method of the second sample block in step ② includes: dividing along the circumferential direction of the second annular test piece, and dividing into 5 second sample sections, and then dividing each second sample section And at least 2 second sample layers are divided, and each second sample layer after division can obtain a plurality of second sample blocks.

Preferably, the length, width and height of the first sample block and the second sample block used for the tensile test are respectively 160±5mm, 20±2mm, and 20±2mm, and the first test piece used for the impact test The length, width and height of the sample block and the second sample block are 60±5mm, 15±2mm and 15±2mm respectively.

Due to the implementation of the above technical solutions, the present invention has the following advantages compared with the prior art:

The sampling method for the quality inspection of the penetration head of the present invention samples both the penetration body and the head body so as to conduct a more complete and comprehensive quality analysis of the entire penetration head, and through the physical and chemical properties of the sample The overall quality of the head of the mechanical penetration of the main steam system is analyzed and comprehensively inspected, and the manufacturing process of the forging of the penetration head can be completely evaluated, which meets the process evaluation requirements of the nuclear power code RCC-M, and does not need to be inspected for the penetration The head of the piece is completely destroyed, and it can still be used as a product after sampling, thereby reducing the cost of sampling to the greatest extent.

Description of drawings

Fig. 1 is a schematic diagram of the three-dimensional structure of the penetrating piece head of the present invention;

Fig. 2 is a schematic diagram of a partial perspective three-dimensional structure of the penetrating piece head of the present invention;

Fig. 3 is the side view structural representation of the first annular test piece of the present invention;

Fig. 4 is the side view structural representation of the second annular test piece of the present invention;

Among them: h1, the stolen position of the first annular test piece; h2, the stolen position of the second annular test piece; d1, the interception position of the first sample segment on the first annular test piece; d2, the second test piece The cut-off position of the sample section on the second ring-shaped test piece.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 1 to 3, a sampling method for the quality inspection of the penetration head. In this example, the penetration head includes a head body and a penetration body. 710~750mm, the outer diameter of the head body is 1420~1500mm, and the inner diameter is 998~1010mm. Sampling method The sampling object is the through head blank with a margin, and the sample is taken after the heat treatment of the blank. Take at least 4 scattered places in the penetrating body to make hardness records, and do surface hardness testing in at least two places (every 200mm) of the head body;

The sampling method includes the following steps: 1. Cutting the first annular test piece on the head body, and dividing the cut first ring-shaped test piece into a plurality of first sample blocks; 2. Cutting the second test piece on the penetrating body. ring-shaped test piece, and the cut-off second ring-shaped test piece is divided into a plurality of second sample blocks; the first ring-shaped test piece has four pieces, and the four first ring-shaped test pieces are obtained from the two ends of the head body respectively. The end and the bottom of the sockets on both sides of the head body are cut off respectively. There are two second ring-shaped test pieces, and the two second ring-shaped test pieces are respectively cut from both ends of the penetrating body. The sampling positions are evenly distributed on the whole penetration head, and the uniformity of the internal quality of the overall penetration head is verified by limited sampling positions. The cost of inspection can be reduced to the greatest extent. By reserving sufficient workpiece allowance, after sampling, the penetration head still has allowance for subsequent finishing.

Step 1. The specific interception method of the first sample block includes: dividing it along the circumferential direction of the first annular test piece, and dividing into a plurality of first sample sections, and then dividing it along the radial direction of the first annular test piece. The first sample section is divided into multiple first sample layers, and then each first sample layer is divided, and each first sample layer after division can obtain multiple first sample layers. For the sample block, the dividing direction for dividing each first sample layer is consistent with the circumferential direction of the first annular test piece.

In this example, each of the four first annular test pieces is divided into two first sample sections, and the two first sample sections are cut from corresponding two sides in the circumferential direction of the first annular test piece. In addition, for the two first ring-shaped test pieces cut from both ends of the head body, the position where the first sample section is cut from one of the first ring-shaped test pieces is the same as the position where the first test piece is cut from the other first ring-shaped test piece. The positions of the sample sections are staggered in the circumferential direction; two first annular test pieces are cut from the bottom of the grooves on both sides of the head body, and the interception position of the first sample section on one of the first ring-shaped test pieces is the same as The positions where the first sample segment is intercepted on the other first ring-shaped test piece are staggered in the circumferential direction. The staggered setting of the above-mentioned intercepting positions can cover the entire sampling position in the circumferential direction of the entire head body, providing more representative samples for subsequent analysis.

After the first ring-shaped test piece → first sample section → first sample layer (at least two) → first sample block is sequentially divided, each first sample layer is divided into a plurality of first samples Among the blocks, there is at least one first sample block for longitudinal tensile test at room temperature, at least one first sample block for longitudinal tensile test at 350°C, and at least one The first sample block for chemical composition analysis, at least one first sample block for metallographic inspection, in addition, there should be at least one sample block for 20°C and 0°C tests in the length direction and circumferential direction, respectively. , -20 ℃ multi-group impact test first sample block, each group impacts three first sample blocks.

The specific intercepting method of the second sample block in step ② is similar to the intercepting method of the first sample block in step ①, and is divided along the circumferential direction of the second annular test piece, and 5 second sample sections are divided, Each second sample segment is then divided into at least two second sample layers, and each second sample layer after division can obtain multiple second sample blocks.

Two of the five second sample sections are located on the corresponding two sides in the circumferential direction, and the other three are located on one side of the straight line where the above two are located,

Among the multiple second sample blocks obtained after the two second sample sections located on the corresponding two sides are divided step by step from the second sample section→second sample layer→second sample block, there is at least one The second sample block for the longitudinal tensile test at room temperature, at least one second sample block for the longitudinal tensile test at a high temperature of 350 ° C, at least one for chemical composition analysis The second sample block, at least one second sample block for metallographic inspection, in addition, there should be at least one for multiple groups of impacts at 20°C, 0°C, and -20°C in the length direction and circumferential direction respectively. Secondary coupons for testing, impact three second coupons per group. After the impact test, KV-T curve analysis is carried out.

Among the multiple second sample blocks obtained after stepwise division of the second sample section → second sample layer → second sample block located in the other three second sample sections, at least one of the second sample blocks should be used at room temperature. In addition, there should be at least second sample blocks for multiple sets of impact tests at 0°C in the longitudinal direction and circumferential direction, and each set of impacts should have three second test blocks. The sample block shall also include 8 second sample blocks for the drop weight test; after the impact and drop weight test, the RT _NDT test shall be carried out.

In addition, the length, width, and height of the first sample block and the second sample block used for the tensile test are 160mm, 20mm, and 20mm respectively, and the first sample block and the second sample block used for the impact test The length, width and height of the block are 60mm, 15mm and 15mm respectively.

In this example, the cutting and dividing methods of each annular test piece, each sample section, each sample layer, and each sample block adopt machining methods, mainly including turning, milling, wire cutting, etc., which can be carried out according to needs. choose.

In summary, the sampling method for the quality inspection of the penetrating piece head of the present invention samples both the penetrating body and the head body, so as to conduct a more complete and comprehensive quality analysis of the entire penetrating piece head, and through the sample The physical and chemical performance analysis of the main steam system comprehensively inspects the overall quality of the main steam system mechanical penetration head forgings, and can conduct a complete evaluation of the manufacturing process of the penetration head, which meets the process evaluation requirements of the nuclear power code RCC-M, and does not The head forging of the penetrating part needs to be completely destroyed, and it can still be used as a product after sampling, thereby reducing the cost of sampling to the greatest extent.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present invention. Equivalent changes or modifications made in the spirit shall fall within the protection scope of the present invention.

Claims (2)

1. The utility model provides a sampling method that penetrating member head quality inspection used, penetrating member head includes the head body, runs through the body, its characterized in that: the sampling object of the sampling method is a penetrating piece seal head blank with a margin, and sampling is carried out after the heat treatment of the blank, and the sampling method comprises the following steps:

(1) cutting a first annular test piece on the seal head body, and dividing the cut first annular test piece into a plurality of first test pieces;

(2) cutting a second annular test piece on the penetrating body, and dividing the cut second annular test piece into a plurality of second test pieces;

after the first annular test piece in the step (1) is divided, at least a first test piece for carrying out a tensile test at room temperature, a first test piece for carrying out a tensile test at a high temperature of 300-400 ℃, a first test piece for carrying out chemical component analysis, a first test piece for metallographic examination, and a first test piece for carrying out an impact test are obtained;

dividing the second annular test piece in the step (2) to obtain at least a second test piece for carrying out a tensile test at room temperature, a second test piece for carrying out a tensile test at a high temperature of 300-400 ℃, a second test piece for carrying out chemical component analysis, a second test piece for metallographic examination and a second test piece for carrying out an impact test;

the four first annular test pieces are respectively intercepted from the two end parts of the seal head body and the bottoms of the nest grooves on the two sides of the seal head body; the two second annular test pieces are respectively intercepted from the two ends of the penetrating body;

the two first annular test pieces are cut from the two ends of the seal head body, and the position of one first annular test piece for cutting the first sample section is staggered with the position of the other first annular test piece for cutting the first sample section in the circumferential direction; the two first annular test pieces are cut from the bottoms of the nest grooves at two sides of the seal head body, and the cutting position of one first annular test piece for cutting the first sample section is staggered with the cutting position of the other first annular test piece for cutting the first sample section in the circumferential direction;

the method for intercepting the first test block in the step (1) comprises the following steps: dividing the first annular test piece along the circumferential direction of the first annular test piece, dividing a plurality of first test piece sections, dividing each first test piece section, and obtaining a plurality of first test pieces by each first test piece section after dividing;

the method for intercepting the first test block in the step (1) further comprises the following steps: dividing the first sample section along the radial direction of the first annular test piece into a plurality of first sample layers, dividing each first sample layer into a plurality of first sample blocks, wherein the dividing direction of dividing each first sample layer is consistent with the circumferential direction of the first annular test piece;

the four first annular test pieces are divided into two first sample sections, and the two first sample sections are intercepted from two corresponding sides of the first annular test piece in the circumferential direction;

the intercepting method of the second test block in the step (2) comprises the following steps: dividing the second annular test piece along the circumferential direction, dividing 5 second sample sections, dividing each second sample section into at least 2 second sample layers, and obtaining a plurality of second sample blocks on each divided second sample layer;

the first annular test piece and the second annular test piece are uniformly distributed along the length direction of the penetrating piece seal head.

2. The sampling method for inspecting quality of a closure of a penetration of claim 1, wherein: the length, width and height of the first and second test pieces for tensile test were 160.+ -. 5mm, 20.+ -. 2mm and 20.+ -. 2mm, respectively, and the length, width and height of the first and second test pieces for impact test were 60.+ -. 5mm, 15.+ -. 2mm and 15.+ -. 2mm, respectively.

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