Superhigh-strength wire rod salt bath heat treatment quality control method

Abstract

The invention discloses an ultrahigh-strength wire rod salt bath heat treatment quality control method which is applied to the technical field of wire rod heat treatment and is suitable for developing high-end wire rod varieties such as bridge cables and ultrahigh-strength prestress wire rods in steel mills and deep processing enterprises. Forming a database according to the trademark of the wire rod, the component fluctuation, the salt bath heat treatment process and the wire performance corresponding to each wire of salt bath heat treatment, and establishing a relation model between the performance and the influence factors of the wire rod; performing concentration and analysis according to requirements of order users on wire performance; carrying out centralized production on the user orders which can share one salt bath heat treatment process; performing performance test on the head and the tail of the wire subjected to salt bath heat treatment, recording performance data into a salt bath heat treatment database, and continuing to enrich a performance model; according to the method, the production organization mode of traditional off-line salt bath heat treatment is eliminated, and stable control over the quality of the salt bath heat treatment wires is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of wire heat treatment, and in particular relates to a quality control method for ultra-high-strength wire salt bath heat treatment. Background Art

[0002] In today's industrial field, products such as bridge cables, ultra-high-strength prestressed steel strands, overhead lines, diamond wires, etc. are booming, and the requirements for material performance are becoming increasingly stringent. On the one hand, the comprehensive performance indicators of tensile strength and area shrinkage rate need to be improved urgently to meet the high-intensity use requirements under various complex working conditions; on the other hand, the fluctuation of product performance is limited to an extremely narrow space, and any slight deviation may affect the stability and reliability of the overall structure.

[0003] The production sources of these wire products are mainly concentrated in steel mills and heat treatment workshops. However, the entire process from raw material supply to processing and forming faces many challenges. The masterbatch composition itself has natural fluctuations. In addition, the aging and untimely updating of production equipment within the steel mills and the poor process stability make the product quality hidden dangers from the source. At the same time, market demand shows a highly personalized trend. Many users have different requirements for wire performance, which requires manufacturers to take into account the special requirements of different users when organizing production.

[0004] The existing quality control method for ultra-high strength wire salt bath heat treatment has the following disadvantages when used: 1. Most steel mills have long followed the traditional production method based on user orders. Under this model, the production process is easily affected by fluctuations in masterbatch composition and equipment and process limitations. Since the composition of each batch of masterbatch is difficult to accurately control, and the production equipment and process cannot flexibly adapt to the changing composition characteristics, the performance of the produced wires fluctuates greatly. According to statistics, when domestic peers use salt bath heat treatment, the strength fluctuation of the same batch of products often exceeds 100MPa. Such a large fluctuation not only generates a large number of unsold products and reduces the yield rate, but also seriously affects the timeliness of delivery and damages the company's benefits. At the same time, end users receive products with uneven performance, which greatly reduces the user experience and causes continuous negative feedback, causing an impact on the brand image; 2. Faced with the problem of product performance fluctuations, some steel mills and users have tried to solve the problem by tightening product standards. They have imposed stricter limits on the upper and lower limits of product composition and performance, hoping to standardize the production process and stabilize product quality. However, in actual operations, the existing production processes of steel mills are mostly established models, and it is difficult to make adaptive adjustments based on new standards in a short period of time. In order to meet strict standards, steel mills have to increase inspection links and adjust process parameters, which undoubtedly increases production costs and still cannot avoid the generation of a large number of carryover products and secondary materials. In extreme cases, some orders are even difficult to deliver because they cannot meet standard requirements, and companies are caught in a dilemma. Summary of the invention

[0005] The purpose of the present invention is to target an existing quality control method for salt bath heat treatment of ultra-high-strength wires. The advantage of the present invention is that it changes the traditional quality control method for wires, transforms the production of user orders into the determination and organization of workshop products, and forms its own product performance database based on a large amount of production data. The performance fluctuations caused by factors such as fluctuations in many components, heat treatment processes, and differences in various lines are analyzed and a model is formed. According to order requirements, a production plan is spontaneously formed and centralized production is carried out, which not only improves production efficiency but also ensures quality stability. It is very suitable for promotion and application in the high-end wire heat treatment industry.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: A method for controlling the quality of ultra-high strength wire salt bath heat treatment, comprising the following steps: S1: Data collection and integration Collect information such as wire rod grade, composition fluctuation, salt bath heat treatment process, wire performance corresponding to each salt bath heat treatment line, and summarize and integrate this information; S2: Initial database creation Based on the information collected and integrated by S1, a performance database is formed, data is initially entered, and the infrastructure is established; S2: Performance correlation exploration Based on the existing database, we conduct in-depth analysis of various factors, establish the relationship between performance and various factors, and explore the regular patterns therein.

[0007] The present invention is further configured as follows: the grades of the wire rod include 87Si, 87MnSi, 92Si and the like.

[0008] The present invention is further configured such that: the composition fluctuation involves elements such as C, Si, Mn, Cr, etc.

[0009] The present invention is further configured as follows: the salt bath heat treatment process involves routing speed, heating temperature, salt bath temperature, etc.

[0010] The present invention is further configured such that the salt bath heat treatment lines are arranged in sequence from one side to the other side according to their positions in the heating furnace.

[0011] The present invention is further configured as follows: the requirements of the order users on the wire material performance are concentrated and analyzed, and the user orders that can share a salt bath heat treatment process are centrally produced.

[0012] The present invention is further configured as follows: the performance test of the head and tail of the wire after the salt bath heat treatment is performed, and the test performance data is recorded in the performance database to further enrich the performance model.

[0013] The present invention is further configured as follows: the performance test uses direct pulling test data, the indicators include tensile strength and surface shrinkage, and the performance test data must be completed within 1 hour.

[0014] The present invention is further configured such that the wire material that does not meet the user's order requirements is re-evaluated based on mechanical properties and changed to other brands.

[0015] The present invention is further configured such that: the other brand names that are modified are recorded as another steel grade and are included in the performance database to prepare for future user order requirements.

[0016] In summary, the present invention has the following beneficial effects: The present invention changes the traditional quality control method of wire rods, transforms the production of user orders into the judgment and organization of workshop products, forms its own product performance database based on a large amount of production data, analyzes the performance fluctuations caused by many influencing factors such as component fluctuations, heat treatment processes, and differences in various lines, and forms a model. According to order requirements, a production plan is spontaneously formed and centralized production is carried out, which not only improves production efficiency but also ensures quality stability. It is very suitable for promotion and application in the high-end wire rod heat treatment industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the number axis of quality influencing factors of the present invention; Figure 2 is a schematic diagram of the trend of salt bath wire under different heat treatment processes of the present invention; Figure 3 is a schematic diagram of a performance prediction model of the present invention; Figure 4 It is a schematic diagram of the performance prediction results of the present invention; Figure 5 It is a schematic flow chart of the quality control method for the ultra-high-strength wire salt bath heat treatment of the present invention. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with the accompanying drawings. Example

[0019] The object of the present invention is to provide a method for quality control of ultra-high strength wire salt bath isothermal treatment, which is applied in the production and quality control of bridge cables, ultra-high strength prestressed steel strands, and masterbatch wire rods for overhead lines.

[0020] 1. According to the brand of wire rod, composition fluctuation, salt bath heat treatment process, the corresponding position of each salt bath heat treatment line and the performance of each wire, a performance database is formed to establish the relationship between the performance and various factors. The brands of wire rod include 87Si, 87MnSi, 92Si, etc. The composition fluctuation involves elements such as C, Si, Mn, Cr, etc. The salt bath heat treatment process involves the wire speed, heating temperature, salt bath temperature, etc. The salt bath heat treatment lines are arranged from one side to the inside according to their positions in the heating furnace. The performance test includes indicators such as tensile strength and surface shrinkage.

[0021] Encode all factors that affect performance and form a number axis, such as Figure 1 As shown in the figure, the number axis is composed of a string of coded numbers. Different αi are located in different positions. Its meaning represents the specifications, steel types, components, heat treatment processes, wire racks, etc. in the database. A large amount of performance fluctuations are collected, and all influencing factors are sorted by weight to form the code on the number axis. The rules of the data model give meaning to the position of αi: (1) The sorting of αi can be regarded as the serial number of the data item; (2) The position of αi can be associated with different data items and the range of data items. For the subdivision of quality data, more stringent internal product quality standards can be constructed under the framework of broad external product standards to meet the quality requirements of high-end products with high stability. αi is used as a grade or identification, and the number of grades can be between 0 and 9. The final model shows a string of numbers: 999999875994····· Each set of numbers essentially represents a mathematical method to describe a complex process, and the relevant quality information can be analyzed, judged, and then processed through the code.

[0022] The properties of 87Si and the properties of the wire frame position are shown in Table 1 Steel Type Specification Frame number Strength range MPa Shrinkage% 87Si Φ14mm 1 1420-1430 ≥28 87Si Φ14mm 2 1430-1450 ≥28 87Si Φ14mm 3 1400-1450 ≥28 87Si Φ14mm 4 1440-1450 ≥28 87Si Φ14mm 5 1450-1460 ≥28 87Si Φ14mm 6 1425-1430 ≥28 87Si Φ14mm 7 1440-1450 ≥28 87Si Φ14mm 8 1450-1455 ≥28 87Si Φ14mm 9 1420-1430 ≥28 87Si Φ14mm 10 1425-1430 ≥28 87Si Φ14mm 11 1430-1440 ≥28 87Si Φ14mm 12 1430-1440 ≥28 87Si Φ14mm 13 1420-1440 ≥28 87Si Φ14mm 14 1420-1435 ≥28 87Si Φ14mm 15 1420-1440 ≥28 87Si Φ14mm 16 1415-1435 ≥28 The performance of 92Si and the performance of the wire frame position are shown in Table 2 Steel Type Specification Wire rack number Strength range MPa Shrinkage% 92Si Φ14mm 1 1585-1600 ≥30 92Si Φ14mm 2 1600-1635 ≥30 92Si Φ14mm 3 1595-1630 ≥30 92Si Φ14mm 4 1600-1605 ≥30 92Si Φ14mm 5 1630-1640 ≥30 92Si Φ14mm 6 1640-1650 ≥30 92Si Φ14mm 7 1615-1645 ≥30 92Si Φ14mm 8 1640-1645 ≥30 92Si Φ14mm 9 1640-1645 ≥30 92Si Φ14mm 10 1580-1620 ≥30 92Si Φ14mm 11 1610-1615 ≥30 92Si Φ14mm 12 1545-1605 ≥30 92Si Φ14mm 13 1590-1600 ≥30 92Si Φ14mm 14 1600-1610 ≥30 92Si Φ14mm 15 1610-1620 ≥30 92Si Φ14mm 16 1615-1625 ≥30 2. According to the order users' requirements for wire performance, the orders from users who can share a salt bath heat treatment process will be concentrated and produced in a centralized manner. The user order demands received each month will be concentrated according to the wire rod brand and performance requirements, and analyzed with the data in the model in the performance database. The user's order demand performance will be mapped with the performance database to form a centralized production plan.

[0023] The customer's demand for a certain type of steel not only involves the composition, but more importantly the mechanical properties. Through the data analysis of Table 1 and Table 2, the same grade of steel has different properties after different furnace numbers, different batches, and production process fluctuations. According to the order's requirements for mechanical properties, especially the tensile strength requirements, the database automatically generates coils with different furnace numbers and components, automatically arranges them to the appropriate batches, and generates a production plan. Production is carried out according to a specific heating furnace production process. The product performance corresponding to different heat treatment processes is as follows: Figure 1 shown.

[0024] The composition fluctuation range of products with different furnace numbers is shown in Table 3 Brand C % Si % Mn % Ni % Cr % N ppm QS92Si 0.93-0.96 0.93-0.98 0.54-0.56 0.008-0.009 0.35-0.37 23-39 3. Carry out performance tests on the wires after salt bath heat treatment at the head and tail, record the test performance data into the performance database, and continue to enrich the performance model.

[0025] 4. After each production schedule is completed, each roll of the product is subjected to head and tail performance tests. The performance test uses direct pulling test data. The indicators include tensile strength and surface shrinkage. The performance test data must be completed within 1 hour. Timely feedback from the performance test is to ensure that the wire is determined and the coil order is assigned in the shortest time. The performance test uses test data that is free of artificial time aging, which ensures that the performance is collected within 1 hour.

[0026] The performance model is established by using neuron performance prediction, and through the calculation of a large amount of data, a performance prediction model under different influencing factors is formed. Figure 2 shown) 5. Wires that do not meet the needs of user orders will be re-evaluated based on mechanical properties and changed to other grades. The changed grades will be included in the performance database as another steel grade to prepare for future user order needs.

[0027] Under extreme conditions, the performance results of the tested wire did not meet the performance requirements of all customers for this centralized production order. Under these conditions, the product was reclassified as other brands. At the same time, data under these extreme conditions continued to be collected into the big data model, and the model was further enriched through neural network big data calculations.

[0028] This method is applied in the production of 92Si wire rod for bridge cable galvanized steel wire. The wire rod specification is 14mm, the tensile strength is required to be between 1560-1620MPa, and the area shrinkage is greater than 30%.

[0029] After the implementation of this invention, according to the process of the invention, the three furnace numbers K22410586, K12410555, K22410584, K22409947 and K12410552 are concentrated in production, and production is carried out according to the wire rack numbers in Table 4. It can be found that all furnaces with different compositions can meet the user's usage requirements under the prediction and scheduling of the large model by adjusting the wire rack position, with a qualified rate of 100%.

[0030] Table 4. Performance of 92Si in different heats and batches under the same production process Furnace No. Steel Type Specification Wire rack number Part Number Intensity range Shrinkage K22410586 92Si 14 16 K47 1560-1570 ≥30 K12410555 92Si 14 3 K38 1560-1580 ≥30 K22410584 92Si 14 5 K11 1580-1590 ≥30 K22409947 92Si 14 11 K36 1580-1620 ≥30 K12410552 92Si 14 9 K36 1570-1610 ≥30 Example

[0031] This method is applied in the production of 87Si wire rod for bridge cable galvanized steel wire. The wire rod specification is 14mm, the tensile strength is required to be between 1380-1420MPa, and the area reduction rate is greater than 28%.

[0032] After the implementation of this invention, according to the process of the invention, the three furnace numbers E22408397, E22408398, E22408396, E22408389 and E22408387 are concentrated in production, and production is carried out according to the wire rack numbers in Table 5. It can be found that all furnaces with different compositions can meet the user's usage requirements under the prediction and scheduling of the large model by adjusting the wire rack position, with a qualified rate of 100%.

[0033] Table 5. Performance of 87Si in different heats and batches under the same production process Furnace No. Steel Type Specification Frame number Part Number Intensity range Shrinkage E22408397 87Si 14 3 050 1395-1405 ≥28 E22408398 87Si 14 9 009 1400-1420 ≥28 E22408396 87Si 14 7 002 1400-1415 ≥28 E22408389 87Si 14 10 023 1400-1410 ≥28 E22408387 87Si 14 11 037 1405-1410 ≥28 Through the present invention, the demand of the Bridge Bureau for hot-rolled wire rods for galvanized steel wire for bridges is met, with a yield rate of over 99%, an annual output of over 20,000 tons, an order delivery rate of 100%, a qualified rate of 100%, and an annual economic benefit of over 20 million.

[0034] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A method for controlling the quality of ultra-high strength wire salt bath heat treatment, comprising the following steps: S1: Data collection and integration Collect information such as wire rod grade, composition fluctuation, salt bath heat treatment process, wire performance corresponding to each salt bath heat treatment line, and summarize and integrate this information; S2: Initial database creation Based on the information collected and integrated by S1, a performance database is formed, data is initially entered, and the infrastructure is established; S2: Performance correlation exploration Based on the existing database, we conduct in-depth analysis of various factors, establish the relationship between performance and various factors, and explore the regular patterns therein.

2. The method for controlling the quality of ultra-high strength wire salt bath heat treatment according to claim 1, characterized in that: The grades of the wire rod include 87Si, 87MnSi, 92Si and the like.

3. The method for controlling the quality of ultra-high strength wire salt bath heat treatment according to claim 1, characterized in that: The composition fluctuation involves elements such as C, Si, Mn, and Cr.

4. The method for controlling the quality of ultra-high strength wire salt bath heat treatment according to claim 1, characterized in that: The salt bath heat treatment process involves routing speed, heating temperature, salt bath temperature, etc.

5. The method for controlling the quality of ultra-high strength wire salt bath heat treatment according to claim 1, characterized in that: The salt bath heat treatment lines are arranged in sequence from one side to the other side according to their positions in the heating furnace.

6. The method for controlling the quality of ultra-high strength wire salt bath heat treatment according to claim 1, characterized in that: The requirements of the order users on the wire material performance are concentrated and analyzed, and the user orders that can share a salt bath heat treatment process are centrally produced.

7. The method for controlling the quality of ultra-high strength wire salt bath heat treatment according to claim 1, characterized in that: The wire after the salt bath heat treatment is subjected to head and tail performance tests, and the test performance data is included in the performance database to further enrich the performance model.

8. The method for controlling the quality of ultra-high strength wire salt bath heat treatment according to claim 7, characterized in that: The performance test adopts direct pulling test data, the indicators include tensile strength and area reduction rate, and the performance test data must be completed within 1 hour.

9. The method for controlling the quality of ultra-high strength wire salt bath heat treatment according to claim 1, characterized in that: The wire materials that do not meet the user's order requirements will be re-evaluated based on the mechanical properties and changed to other brands.

10. The method for controlling the quality of ultra-high strength wire salt bath heat treatment according to claim 1, characterized in that: The other grades that will be revised will be included in the performance database as another steel grade to prepare for future user order requirements.

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