Manufacturing method of steel for corrosion-resistant saw blade

Abstract

The invention discloses corrosion-resistant high-strength saw blade steel and a manufacturing method thereof, and belongs to the field of metallurgy and metal materials. The steel for the saw blade comprises the following components in percentage by mass: 0.63 to 0.70 percent of C, 0.46 to 0.62 percent of S i, 0.79 to 0.98 percent of Mn, less than or equal to 0.033 percent of P, less than or equal to 0.014 percent of S, 0.15 to 0.35 percent of Cr, 0.44 to 0.68 percent of Cu, 0.23 to 0.35 percent of N i and the balance of Fe and impurities. The manufacturing method comprises the steps of molten iron pretreatment, converter smelting, LF refining, VD vacuum treatment, continuous casting, casting blank slow cooling, steel billet heating, rolling, heat treatment, straightening, inspection and the like. According to the corrosion-resistant high-strength steel for the saw blade, a uniform pearlite structure is obtained, the Brinell hardness of a product is larger than 340 HBW, the tensile strength is larger than 1180 MPa, and the corrosion resistance is improved by 44% or above compared with that of conventional steel for the saw blade.

Description

Technical Field

[0001] This invention belongs to the field of metal materials technology, and particularly relates to a method for manufacturing corrosion-resistant steel for saw blades. It is applicable to the manufacture of saw blades that need to withstand humid environments, cutting fluid corrosion, and chemical erosion in various scenarios such as wood processing, metal cutting, and stone cutting, and is especially suitable for high-strength saw blade products that operate under complex corrosive conditions for extended periods. Background Technology

[0002] As a core component in the cutting and processing field, the performance of saw blades directly determines processing accuracy, efficiency, and operating costs. In practical applications, saw blades often face harsh working environments: in wood processing scenarios, the moisture contained in the wood and the resin produced during processing easily adhere to the surface of the saw blade, creating a humid and corrosive environment; in metal cutting scenarios, cutting fluids (containing oil, emulsions, chemical additives, etc.) are in contact with the saw blade for a long time, which can easily cause electrochemical corrosion; in some outdoor operations or special industries (such as cutting for chemical and marine engineering), saw blades are also subject to corrosion from acid, alkali, and salt spray in the atmosphere.

[0003] Current saw blade steel designs primarily focus on balancing hardness, wear resistance, and toughness, with insufficient optimization for corrosion resistance. This leads to problems such as edge corrosion, pitting corrosion, and crack propagation in complex corrosive conditions. This not only shortens the saw blade's lifespan (conventional saw blades only last 1-3 months under humid conditions with cutting fluid) but also reduces its strength due to corrosion, increasing the risk of breakage during cutting. Furthermore, frequent saw blade replacements increase operating costs and reduce production efficiency.

[0004] Currently, the industry lacks saw blade steel formulations and mature industrial manufacturing technologies that balance high strength, high toughness, and excellent corrosion resistance. Existing improvement solutions mostly rely on surface coatings to enhance corrosion resistance, but these coatings are prone to peeling off under cutting impact and friction, failing to fundamentally solve the corrosion problem. Therefore, developing a saw blade steel and manufacturing method that integrates corrosion resistance and high strength through composition optimization and process synergy has become a pressing technical challenge for the industry. Summary of the Invention

[0005] To overcome the shortcomings of existing saw blade steels, such as insufficient corrosion resistance and difficulty in achieving both high strength and corrosion resistance, the purpose of this invention is to provide a corrosion-resistant high-strength saw blade steel with a reasonable composition design and stable manufacturing process, as well as a manufacturing method. This allows the saw blade steel to possess excellent tensile strength and hardness while significantly improving its resistance to moisture, cutting fluid, and acid and alkali media corrosion, thereby extending the service life of the saw blade and reducing usage costs.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] This invention discloses a method for manufacturing corrosion-resistant saw blade steel, comprising the following steps:

[0008] Hot metal pretreatment: Control the S content in the hot metal after pretreatment to be ≤0.010% and P content to be ≤0.015%;

[0009] Converter smelting: tapping temperature 1605~1660℃, carbon content 0.04~0.10%, phosphorus content ≤0.07%, alloying deoxidation is added during tapping;

[0010] LF refining: using strongly reducing refining slag with basicity R = 2.8 to 3.2, refining in-situ temperature 1522 to 1598℃, out-of-situ temperature 1613 to 1650℃, and processing time 25 to 58 min;

[0011] VD vacuum treatment: Total vacuum treatment time 20-30 min, deep vacuum time ≥20 min, deep vacuum degree 19-25 kPa, and stand for 12-30 min after treatment;

[0012] Continuous casting: superheat ≤30℃, constant casting speed 0.8~1.2m / min, electromagnetic stirring in the crystallizer, secondary atomized cooling;

[0013] Slow cooling of billet: slow cooling time ≥48h, cooling rate ≤5℃ / h, and billet is removed from furnace after cooling to ≤200℃;

[0014] Billet heating: Total heating time 3.5~5.5h, heating section ≥2h40min, soaking section ≥50min, preheating section ≤800℃, heating section I ≤1100℃, heating section II upper and lower 1100~1280℃, soaking section upper and lower 1150~1260℃, furnace temperature ≤1080℃ when rolling stops;

[0015] Rolling: After high-pressure water descaling, the initial rolling temperature is 1080~1150℃, the final rolling temperature is 940~960℃, and the reduction per pass is ≤15%;

[0016] Heat treatment: air cooling, starting temperature 740~790℃, ending temperature 480~520℃, cooling rate 2.3~2.6℃ / s;

[0017] Straightening and inspection: Straightening temperature ≤60℃, only one roller straightening, ultrasonic testing for each piece, no defects exceeding the equivalent of Φ2.0mm artificial defects;

[0018] The chemical composition of the corrosion-resistant high-strength saw blade steel by mass percentage is as follows: C: 0.63-0.70%, Si: 0.46-0.62%, Mn: 0.79-0.98%, P: ≤0.033%, S: ≤0.014%, Cr: 0.15-0.35%, Cu: 0.44-0.68%, Ni: 0.23-0.35%, of which C+Si+Mn: 1.8-2.3%, Cu+Ni+Cr: 0.7-1.0%, and the remainder is Fe and unavoidable impurities.

[0019] Furthermore, the chemical composition of the corrosion-resistant high-strength saw blade steel by mass percentage is as follows: C: 0.66%, Si: 0.54%, Mn: 0.86%, P: 0.016%, S: 0.008%, Cr: 0.24%, Cu: 0.59%, Ni: 0.30%; the remainder is Fe and unavoidable impurities.

[0020] Furthermore, the chemical composition of the corrosion-resistant high-strength saw blade steel by mass percentage is as follows: C: 0.68%, Si: 0.51%, Mn: 0.98%, P: 0.016%, S: 0.009%, Cr: 0.24%, Cu: 0.44%, Ni: 0.23%; the remainder is Fe and unavoidable impurities.

[0021] Furthermore, the chemical composition of the corrosion-resistant high-strength saw blade steel by mass percentage is as follows: C: 0.70%, Si: 0.62%, Mn: 0.94%, P: 0.016%, S: 0.010%, Cr: 0.24%, Cu: 0.47%, Ni: 0.24%; the remainder is Fe and unavoidable impurities.

[0022] Furthermore, the corrosion-resistant high-strength saw blade steel has a uniform pearlite microstructure with a grain size ≥ 8.

[0023] Furthermore, the corrosion-resistant high-strength saw blade steel has the following characteristics: Brinell hardness > 340HBW, tensile strength > 1180MPa, elongation ≥ 10%, and yield strength > 950MPa.

[0024] Furthermore, the corrosion-resistant high-strength saw blade steel described herein exhibits a corrosion resistance that is more than 44% higher than that of conventional 75# saw blade steel after undergoing a 168-hour full-immersion rotating hanging method corrosion test.

[0025] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0026] This invention achieves a uniform pearlitic structure in steel through component optimization and precise control of the entire process. The product has a Brinell hardness >340HBW, tensile strength >1180MPa, and corrosion resistance that is more than 44% higher than that of conventional saw blade steel. It is suitable for complex working conditions such as humidity and cutting fluid corrosion, and can extend the service life of saw blades. It is applicable to saw blade manufacturing for various scenarios such as woodworking, metalworking, and stone cutting.

[0027] The composition is scientifically and rationally designed. Through the synergistic ratio of C, Si, Mn with Cu, Ni, and Cr, the corrosion resistance of the steel is significantly improved while ensuring high strength and high hardness, thus solving the corrosion problem of the saw blade from the matrix level.

[0028] The manufacturing process is mature and stable, and adopts full-process control of "molten iron pretreatment - converter smelting - LF refining - VD vacuum treatment - continuous casting - slow cooling - precision heating - universal rolling - air jet cooling" to ensure that the internal structure of the steel is uniform, the density is high and the defects are few, which can realize large-scale industrial production.

[0029] The product boasts superior performance, with a Brinell hardness >340HBW, tensile strength >1180MPa, elongation ≥10%, and corrosion resistance that is more than 44% higher than that of conventional saw blade steel. It also extends the service life by 2 to 3 times, significantly reducing the frequency of saw blade replacement and operating costs.

[0030] With a wide range of applications, it can be used to manufacture various types of saw blades such as woodworking saw blades, metal cutting saw blades, and stone saw blades. It is especially suitable for complex corrosive working conditions such as humidity, cutting fluid corrosion, and acid, alkali, and salt spray, and has broad application prospects. Attached Figure Description

[0031] The present invention will be further described below with reference to the accompanying drawings.

[0032] Figure 1 This is a comparison chart of the corrosion resistance of the saw blade steel of this invention and conventional 75# steel; the horizontal axis represents the corrosion test time (h), and the vertical axis represents the corrosion rate (mm / a); the chart contains two curves, namely "the saw blade steel of this invention (Example 1)" and "the conventional 75# saw blade steel (comparative example)"; the curves show that within the 168h test period, the corrosion rate of the saw blade steel of this invention is consistently lower than that of conventional 75# steel, ultimately improving corrosion resistance by 73.0%, directly demonstrating the corrosion resistance advantage of this invention.

[0033] Figure 2 This is a microstructure diagram of the steel used in the saw blade of the present invention (magnified 1000 times). The diagram shows the microstructure morphology of the steel used in the saw blade after heat treatment, which is mainly composed of uniformly distributed pearlite. The pearlite lamellae are arranged neatly with uniform spacing, and the grain size is ≥8 (8.5 in the figure). There are no obvious coarse grains, segregation or inclusion defects, which confirms the role of composition design and process control in ensuring the uniformity of the microstructure. Detailed Implementation

[0034] A corrosion-resistant high-strength saw blade steel with a reasonable composition design and stable manufacturing process, and its manufacturing method, are disclosed. This invention enables the saw blade steel to have excellent tensile strength and hardness, while significantly improving its resistance to moisture, cutting fluid, and acid and alkali media corrosion, thus extending the service life of the saw blade and reducing the cost of use.

[0035] Chemical composition of steel for saw blades

[0036] The corrosion-resistant, high-strength saw blade steel of the present invention has the following chemical composition by mass percentage:

[0037] Table 1 Chemical composition of steel for saw blades (mass percentage, %)

[0038]

[0039]

[0040] Ingredient design principles:

[0041] C, Si, and Mn work synergistically to ensure the strength and hardenability of steel. C is the core element for improving the hardness and strength of steel, Si can enhance the oxidation resistance and corrosion resistance of steel, and Mn can refine the grains and improve the toughness and wear resistance of steel. The total amount of the three is controlled at 1.8-2.3% to achieve a balance between strength and toughness.

[0042] Cu, Ni, and Cr are the core alloying elements for corrosion resistance. Cu can form a dense oxide film on the steel surface, which hinders the penetration of corrosive media; Ni can improve the toughness and pitting resistance of steel; Cr can enhance the passivation ability of steel and improve its resistance to acid and alkali corrosion. The total amount of the three is controlled at 0.7% to 1.0% to maximize corrosion resistance without significantly increasing costs.

[0043] Strictly control the content of P and S impurities, with P ≤ 0.033% and S ≤ 0.014%, to avoid the segregation of impurity elements at grain boundaries and prevent the steel from becoming less tough and more susceptible to corrosion.

[0044] Manufacturing method

[0045] The method for manufacturing corrosion-resistant high-strength saw blade steel of the present invention includes the following steps, and the key process parameters are summarized in the table below:

[0046] Table 2 Summary of Key Process Parameters

[0047]

[0048] Detailed process instructions:

[0049] Hot metal pretreatment: The hot metal is desulfurized and dephosphorized to control the S content in the hot metal after pretreatment to ≤0.010% and P content to ≤0.015%, ensuring the purity of the raw hot metal and laying the foundation for the quality of the subsequent molten steel.

[0050] Converter smelting: Pretreated molten iron is fed into a converter for smelting. During the smelting process, slag-forming auxiliary materials such as lime and fluorite are added to remove impurities and harmful elements from the molten steel. During tapping, according to the chemical composition requirements of the finished product, ferrosilicon, ferromanganese, ferrochrome, nickel plates, copper alloys, etc., are added for deoxidation and alloying, and the content of each element is precisely controlled. Converter smelting process parameters: tapping temperature 1605~1660℃, carbon content 0.04~0.10%, phosphorus content ≤0.07%, tapping time 8~12min.

[0051] LF Refining: Molten steel from the converter is fed into the LF furnace for refining. A moderately basic (R = 2.8–3.2) strongly reducing refining slag (CaO-Al₂O₃-SiO₂ system) is used. Argon gas stirring promotes the reaction between the steel and slag, removing inclusions and gases from the molten steel and homogenizing its composition and temperature. LF refining process parameters: refining in-situ temperature 1522–1598℃, refining out-of-situ temperature 1613–1650℃, refining time 25–58 min, argon gas stirring intensity 0.3–0.5 m. 3 / min.

[0052] VD Vacuum Treatment: After LF refining, the molten steel is sent to a VD furnace for deep vacuum treatment to remove gases such as H and N, further purifying the steel and improving its density and toughness. VD Vacuum Treatment Process Parameters: Total vacuum treatment time 20-30 min, of which deep vacuum time (vacuum degree ≤25 kPa) ≥20 min, deep vacuum degree 19-25 kPa, steel temperature after VD treatment 1500-1580℃, and settling time after treatment 12-30 min.

[0053] Continuous casting: The VD-treated molten steel is continuously cast using an arc-shaped continuous casting machine. During the continuous casting process, the superheat is controlled to ≤30℃, and a constant casting speed (0.8~1.2m / min) is used. The crystallizer uses electromagnetic stirring, and secondary cooling is achieved using air mist cooling to ensure that the internal structure of the cast billet is uniform and free from defects such as shrinkage cavities and porosity. The dimensions of the continuously cast steel billet are 280mm×380mm (which can be adjusted according to the saw blade size requirements), and the chemical composition of the steel billet meets the composition requirements of the saw blade steel mentioned above in this invention.

[0054] Slow cooling of billets: After continuous casting, the billets are sent to a slow cooling pit for slow cooling treatment. The slow cooling time is ≥48h. During the slow cooling process, the cooling rate is controlled to be ≤5℃ / h until the billet temperature drops to ≤200℃ before being taken out of the furnace. This eliminates the residual stress inside the billet, prevents the billet from cracking, and improves the uniformity of the billet structure.

[0055] Billet Heating: The slowly cooled billet is fed into a walking beam furnace for heating, using a segmented heating process to ensure uniform heating and avoid overheating or underheating. Heating process parameters: Total heating time 3.5–5.5 hours, with the heating section lasting ≥2 hours and 40 minutes and the soaking section lasting ≥50 minutes; Furnace temperature control for each section: Preheating section ≤800℃, Adding section I ≤1100℃, Adding section II (upper and lower) 1100–1280℃, Soaking section (upper and lower) 1150–1260℃; If rolling is stopped for any reason, the furnace temperature should be rapidly reduced to ≤1080℃ to prevent coarse grains in the billet.

[0056] Rolling: A universal rolling process is adopted. Before rolling, the surface of the steel billet is descaled by high-pressure water (water pressure ≥18MPa) to remove iron oxide scale from the billet surface and prevent iron oxide scale from being pressed into the billet surface and affecting quality. Rolling process parameters: initial rolling temperature 1080~1150℃, final rolling temperature 940~960℃. Multi-pass deformation is used during rolling, and the reduction per pass is controlled to ≤15% to ensure that the internal structure of the steel is dense and the grains are refined.

[0057] Heat Treatment: The rolled steel for saw blades undergoes heat treatment using air-jet cooling. By precisely controlling the cooling parameters, a uniform pearlitic structure is obtained, balancing strength, hardness, and toughness. Heat treatment process parameters: Cooling start temperature 740–790℃ (air-jet cooling is initiated after natural cooling to this temperature following rolling), cooling end temperature 480–520℃, cooling rate 2.3–2.6℃ / s. During the cooling process, uniform cooling of the steel surface is ensured, with no localized overcooling or undercooling.

[0058] Straightening and Inspection: After heat treatment, the steel for saw blades is fed into a straightening machine for straightening. The straightening temperature is ≤60℃, and only one roller straightening is allowed. After straightening, the flatness error of the steel is ≤0.5mm / m, with no wavy bends, hard bends, or obvious twists. After straightening, each saw blade is subjected to ultrasonic flaw detection according to the requirements of TB / T2344-2012 standard to ensure that there are no inclusions, cracks, or other defects in the steel that exceed the equivalent of Φ2.0mm artificial defects. At the same time, chemical composition analysis, hardness testing, tensile strength testing, and corrosion resistance testing are performed on the steel. Only after all performance indicators are qualified can the steel be put into storage.

[0059] Product performance indicators

[0060] The corrosion-resistant, high-strength saw blade steel of the present invention, after being processed by the above manufacturing method, has the following performance indicators:

[0061] Microstructure: Uniform pearlite structure, grain size ≥ 8 (see attached). Figure 2 As shown, it is level 8.5;

[0062] Hardness: Brinell hardness (HBW) > 340;

[0063] Mechanical properties: tensile strength (Rm) > 1180 MPa, elongation (A) ≥ 10%, yield strength (ReL) > 950 MPa;

[0064] Corrosion resistance: After a full immersion rotating blade corrosion test (simulating cutting fluid and a humid environment, test period 168 hours), the corrosion resistance is improved by more than 44% compared to conventional saw blade steel (such as 75 steel) (see attached). Figure 1 (as shown);

[0065] Surface quality: The steel surface is free of defects such as iron oxide scale, cracks, inclusions, and scabs, and the surface roughness Ra≤6.3μm.

[0066] The technical solution of the present invention will be described in detail below through specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0067] Example 1

[0068] Chemical composition (mass percentage): C: 0.66%, Si: 0.54%, Mn: 0.86%, P: 0.016%, S: 0.008%, Cr: 0.24%, Cu: 0.59%, Ni: 0.30%; where C+Si+Mn=2.06%, Cu+Ni+Cr=1.13% (meeting the requirement of 0.7~1.0%).

[0069] Manufacturing process parameters:

[0070] Converter tapping temperature: 1630℃, carbon content: 0.07%, phosphorus content: 0.04%;

[0071] LF refining: in-situ temperature 1550℃, out-of-situ temperature 1625℃, processing time 35min;

[0072] VD vacuum treatment: vacuum treatment time 25min, deep vacuum degree 22kPa, VD post-temperature 1530℃, standing time 18min;

[0073] Continuous casting: superheat 25℃, casting speed 1.0m / min;

[0074] Billet heating: Total heating time 4.0h, heating section 2h50min, soaking section 55min, furnace temperature of each section controlled according to process requirements;

[0075] Rolling: Initial rolling temperature 1120℃, final rolling temperature 950℃;

[0076] Heat treatment: Cooling start temperature 760℃, end temperature 500℃, cooling rate 2.4℃ / s;

[0077] Straightening temperature: 50℃.

[0078] Product performance:

[0079] Microstructure: homogeneous pearlite;

[0080] Brinell hardness: 342 HBW;

[0081] Mechanical properties: tensile strength 1192 MPa, elongation 12.5%, yield strength 965 MPa;

[0082] Corrosion resistance: After a 168-hour full immersion rotating hanging blade corrosion test, the corrosion rate was 0.085 mm / a, which is 73.0% higher than that of conventional No. 75 saw blade steel (corrosion rate 0.315 mm / a).

[0083] Example 2

[0084] Chemical composition (mass percentage): C: 0.68%, Si: 0.51%, Mn: 0.98%, P: 0.016%, S: 0.009%, Cr: 0.24%, Cu: 0.44%, Ni: 0.23%; where C+Si+Mn=2.17%, Cu+Ni+Cr=0.91% (meeting the requirement of 0.7~1.0%).

[0085] Manufacturing process parameters:

[0086] Converter tapping temperature: 1645℃, carbon content: 0.08%, phosphorus content: 0.05%;

[0087] LF refining: in-situ temperature 1565℃, out-of-situ temperature 1630℃, processing time 40min;

[0088] VD vacuum treatment: vacuum treatment time 28min, deep vacuum degree 20kPa, VD temperature 1545℃, standing time 22min;

[0089] Continuous casting: superheat 28℃, casting speed 0.9m / min;

[0090] Billet heating: Total heating time 4.5h, heating section 3h00min, soaking section 60min, furnace temperature of each section controlled according to process requirements;

[0091] Rolling: Initial rolling temperature 1130℃, final rolling temperature 945℃;

[0092] Heat treatment: Cooling start temperature 775℃, end temperature 490℃, cooling rate 2.5℃ / s;

[0093] Straightening temperature: 55℃.

[0094] Product performance:

[0095] Microstructure: homogeneous pearlite;

[0096] Brinell hardness: 355 HBW;

[0097] Mechanical properties: tensile strength 1223 MPa, elongation 12.0%, yield strength 980 MPa;

[0098] Corrosion resistance: After a 168-hour full immersion rotating hanging blade corrosion test, the corrosion rate was 0.108 mm / a, which is 65.7% higher than that of conventional No. 75 saw blade steel.

[0099] Example 3

[0100] Chemical composition (mass percentage): C: 0.70%, Si: 0.62%, Mn: 0.94%, P: 0.016%, S: 0.010%, Cr: 0.24%, Cu: 0.47%, Ni: 0.24%; where C+Si+Mn=2.26%, Cu+Ni+Cr=0.95% (meeting the requirement of 0.7~1.0%).

[0101] Manufacturing process parameters:

[0102] Converter tapping temperature: 1620℃, carbon content: 0.06%, phosphorus content: 0.03%;

[0103] LF refining: in-situ temperature 1540℃, out-of-situ temperature 1615℃, processing time 32min;

[0104] VD vacuum treatment: vacuum treatment time 22min, deep vacuum degree 24kPa, VD post-temperature 1520℃, standing time 15min;

[0105] Continuous casting: superheat 22℃, casting speed 1.1m / min;

[0106] Billet heating: Total heating time 3.8h, heating section 2h45min, soaking section 58min, furnace temperature of each section controlled according to process requirements;

[0107] Rolling: Initial rolling temperature 1100℃, final rolling temperature 955℃;

[0108] Heat treatment: Cooling start temperature 750℃, end temperature 510℃, cooling rate 2.3℃ / s;

[0109] Straightening temperature: 45℃.

[0110] Product performance:

[0111] Microstructure: homogeneous pearlite;

[0112] Brinell hardness: 358 HBW;

[0113] Mechanical properties: tensile strength 1235 MPa, elongation 11.8%, yield strength 990 MPa;

[0114] Corrosion resistance: After a 168-hour full immersion rotating blade corrosion test, the corrosion rate was 0.112 mm / a, which is 64.4% higher than that of conventional 75# saw blade steel.

[0115] Comparative example (steel used for standard 75# saw blades)

[0116] Chemical composition (mass percentage): C: 0.72%, Si: 0.28%, Mn: 0.85%, P: 0.020%, S: 0.012%, Cr: 0.10%, Cu: 0.15%, Ni: 0.10%; where C+Si+Mn=1.85%, Cu+Ni+Cr=0.35%.

[0117] Manufacturing process: conventional rolling + residual heat quenching process, cooling rate 1.5~1.8℃ / s.

[0118] Product performance:

[0119] Brinell hardness: 320 HBW;

[0120] Mechanical properties: tensile strength 1050 MPa, elongation 9.5%;

[0121] Corrosion resistance: After a 168-hour full immersion rotating plate corrosion test, the corrosion rate was 0.315 mm / a.

[0122] The performance comparison between the examples and the comparative examples is detailed in the table below:

[0123] Table 3. Performance Comparison of Examples and Comparative Examples

[0124]

[0125] As can be seen from the comparison of the above embodiments and comparative examples, the steel for saw blades of the present invention, through optimized chemical composition design (reasonable control of the total amount of C+Si+Mn and Cu+Ni+Cr), combined with precise smelting, rolling and heat treatment processes, has superior mechanical properties such as Brinell hardness, tensile strength and elongation compared to conventional steel for saw blades, and its corrosion resistance is significantly improved (by more than 44%), fully meeting the requirements for high-strength saw blades under complex corrosive conditions.

[0126] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for manufacturing corrosion-resistant saw blade steel, characterized in that: Includes the following steps: Hot metal pretreatment: Control the S content in the hot metal after pretreatment to be ≤0.010% and P content to be ≤0.015%; Converter smelting: tapping temperature 1605~1660℃, carbon content 0.04~0.10%, phosphorus content ≤0.07%, alloying deoxidation during tapping; LF refining: using strongly reducing refining slag with basicity R = 2.8 to 3.2, refining in-situ temperature 1522 to 1598℃, out-of-situ temperature 1613 to 1650℃, and processing time 25 to 58 min; VD vacuum treatment: Total vacuum treatment time 20-30 min, deep vacuum time ≥20 min, deep vacuum degree 19-25 kPa, and stand for 12-30 min after treatment; Continuous casting: superheat ≤30℃, constant casting speed 0.8~1.2m / min, electromagnetic stirring in the crystallizer, secondary atomized cooling; Slow cooling of billet: slow cooling time ≥48h, cooling rate ≤5℃ / h, and billet is removed from furnace after cooling to ≤200℃; Billet heating: Total heating time 3.5~5.5h, heating section ≥2h40min, soaking section ≥50min, preheating section ≤800℃, heating section I ≤1100℃, heating section II upper and lower 1100~1280℃, soaking section upper and lower 1150~1260℃, furnace temperature ≤1080℃ when rolling stops; Rolling: After high-pressure water descaling, the initial rolling temperature is 1080~1150℃, the final rolling temperature is 940~960℃, and the reduction per pass is ≤15%; Heat treatment: air cooling, starting temperature 740~790℃, ending temperature 480~520℃, cooling rate 2.3~2.6℃ / s; Straightening and inspection: Straightening temperature ≤60℃, only one roller straightening, ultrasonic testing for each piece, no defects exceeding the equivalent of Φ2.0mm artificial defects; The chemical composition of the corrosion-resistant high-strength saw blade steel by mass percentage is as follows: C: 0.63-0.70%, Si: 0.46-0.62%, Mn: 0.79-0.98%, P: ≤0.033%, S: ≤0.014%, Cr: 0.15-0.35%, Cu: 0.44-0.68%, Ni: 0.23-0.35%, of which C+Si+Mn: 1.8-2.3%, Cu+Ni+Cr: 0.7-1.0%, and the remainder is Fe and unavoidable impurities.

2. The method for manufacturing corrosion-resistant saw blade steel according to claim 1, characterized in that: The chemical composition of the corrosion-resistant high-strength saw blade steel by mass percentage is as follows: C: 0.66%, Si: 0.54%, Mn: 0.86%, P: 0.016%, S: 0.008%, Cr: 0.24%, Cu: 0.59%, Ni: 0.30%; the remainder is Fe and unavoidable impurities.

3. The method for manufacturing corrosion-resistant saw blade steel according to claim 1, characterized in that: The chemical composition of the corrosion-resistant high-strength saw blade steel by mass percentage is as follows: C: 0.68%, Si: 0.51%, Mn: 0.98%, P: 0.016%, S: 0.009%, Cr: 0.24%, Cu: 0.44%, Ni: 0.23%; the remainder is Fe and unavoidable impurities.

4. The method for manufacturing corrosion-resistant saw blade steel according to claim 1, characterized in that: The chemical composition of the corrosion-resistant high-strength saw blade steel by mass percentage is as follows: C: 0.70%, Si: 0.62%, Mn: 0.94%, P: 0.016%, S: 0.010%, Cr: 0.24%, Cu: 0.47%, Ni: 0.24%; the remainder is Fe and unavoidable impurities.

5. The method for manufacturing corrosion-resistant saw blade steel according to claim 1, characterized in that: The corrosion-resistant high-strength saw blade steel has a uniform pearlite microstructure with a grain size ≥ 8.

6. The method for manufacturing corrosion-resistant saw blade steel according to claim 1, characterized in that: The corrosion-resistant high-strength saw blade steel has the following characteristics: Brinell hardness > 340HBW, tensile strength > 1180MPa, elongation ≥ 10%, and yield strength > 950MPa.

7. The method for manufacturing corrosion-resistant saw blade steel according to claim 1, characterized in that: The corrosion-resistant high-strength saw blade steel described herein, after a 168-hour full-immersion rotating hanging method corrosion test, showed a corrosion resistance that was more than 44% higher than that of conventional No. 75 saw blade steel.

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