Tough wear-resistant cold-rolled sheet for cutter and processing method thereof

Abstract

The invention provides a tough wear-resistant cold-rolled sheet for a cutter. The tough wear-resistant cold-rolled sheet comprises the following chemical components in percentage by weight: 0.18-0.24% of C, 0.17-0.35% of Si, 0.80-1.0% of Mn, less than or equal to 0.020% of P, less than or equal to 0.020% of S and the balance of Fe. The steel comprises the following components in percentage by weight: less than or equal to 0.020% of S, 0.10-0.25% of Cr, 0.01-0.05% of Ni, 0.05-0.10% of Cu and the balance of Fe and inevitable impurities. The invention further provides a processing method of the wear-resistant cold-rolled sheet with toughness for the cutter. The processing method sequentially comprises the following steps of smelting, continuous casting, hot rolling, acid pickling, cold rolling, cover withdrawing and flattening. The prepared wear-resistant cold-rolled sheet for the cutter has good performance, the final yield strength is larger than or equal to 260 MPa, the tensile strength is larger than or equal to 420 MPa, the A50 ductility is larger than or equal to 28%, the HRB hardness is 65-75, and the wear-resistant cold-rolled sheet is tough and suitable for manufacturing the cutter, a chain and the like.

Description

Technical Field

[0001] The invention relates to the technical field of metal material processing, and in particular to a wear-resistant cold-rolled plate for a tool which is both strong and tough and a processing method thereof. Background Art

[0002] With the continuous advancement of industrial technology, higher requirements are placed on the strength, corrosion resistance and processing performance of cold-rolled sheet materials. For products such as knives and chains, ordinary cold-rolled sheets are difficult to meet their requirements for strength, formability and wear resistance. Therefore, it is particularly important to develop a new type of high-strength and corrosion-resistant cold-rolled sheet and its preparation method.

[0003] The Chinese patent application number 201611164493.8, "A method for processing high-strength and high-wear-resistant stainless steel cold-rolled plates", relates to a method for processing high-strength and high-wear-resistant stainless steel cold-rolled plates, including (1) raw material processing; (2) rolling; (3) annealing and pickling; (4) polishing and grinding; (5) electrolytic passivation; this patent is a method for processing stainless steel cold-rolled plates and is not applicable to the processing of non-stainless steel.

[0004] The Chinese patent application number 201010023160.X, "A Wear-Resistant Steel Plate", relates to a wear-resistant steel plate, whose chemical composition (weight %) is: C: 0.31-0.40%, Si: 0.10-0.80%, Mn: 0.20-1.50%, P: ≤0.050%, S: ≤0.030%, Cr: 0-1.50%, Mo: 0-0.80%, Al: 0.02-0.20%, B: 0.0005-0.0040%, Ti: 0-0.10%, Ca: 0-0.030%, 0.10%≤Cr+Mo≤1.80%, 0.05%≤Al+Ti≤0.18%, and the balance is Fe and unavoidable impurities. The manufacturing method of the wear-resistant steel plate includes the steps of smelting, refining, casting, rolling, quenching and tempering. This patent is for wear-resistant steel for construction machinery, and it is not a cold-rolled product and is not suitable for the processing of cold-rolled plates for cutting tools.

[0005] Existing wear-resistant steels are difficult to meet the comprehensive requirements of strength, hardness, wear resistance and forming for knives, chains, etc. Summary of the invention

[0006] The purpose of the present invention is to address the defects of the prior art and provide a wear-resistant cold-rolled plate for cutting tools that is both strong and tough and a processing method thereof. By adjusting the elemental composition of the cold-rolled plate and using a annealing process to improve the metallographic structure of the cold-rolled plate, the comprehensive requirements of cutting tools, chains, etc. for strength, hardness, wear resistance and forming can be met.

[0007] The present invention provides a wear-resistant cold-rolled plate for cutting tools that is both strong and tough, and the chemical composition thereof is as follows by weight percentage:

[0008] C: 0.18%~0.24%, Si: 0.17%~0.35%, Mn: 0.80%~1.0%, P≤0.020%;

[0009] S≤0.020%, Cr: 0.10%~0.25%, Ni: 0.01%~0.05%, Cu: 0.05%~0.10%, and the balance is Fe and inevitable impurities.

[0010] Furthermore, the metallographic structure of the cold-rolled sheet is ferrite and pearlite, and the proportion of pearlite is 10% to 20%.

[0011] A method for processing a strong and tough wear-resistant cold-rolled plate for a tool, comprising the following steps in sequence: smelting, continuous casting, hot rolling, pickling, cold rolling, annealing, and leveling; wherein:

[0012] The smelting temperature is 1550°C to 1600°C;

[0013] The continuous casting adopts tundish heating and electromagnetic stirring, controls the temperature gradient to be ≤120°C / m, and controls the continuous casting speed to be 0.8m / min-1.2m / min;

[0014] The hot rolling temperature is 1150°C to 1200°C, and the total hot rolling reduction ratio is ≥ 60%;

[0015] The total cold rolling reduction rate is 55% to 65%;

[0016] The hood annealing is to put the cold rolled sheet into a hood annealing furnace, preheat it under a protective atmosphere, anneal it after preheating, and cool it to room temperature after annealing.

[0017] The flattening elongation is 0.5% to 1.0%.

[0018] Furthermore, the smelting temperature is 1570°C to 1595°C.

[0019] Furthermore, the continuous casting adopts tundish heating and electromagnetic stirring, controls the temperature gradient to be ≤100°C / m, and controls the continuous casting speed to be 0.9m / min to 1.1m / min.

[0020] Furthermore, the hot rolling temperature is 1172°C to 1198°C, and the total hot rolling reduction ratio is ≥ 60% to 70%. Further, the hot rolling is followed by cooling, and the cooling rate is controlled to be 20°C / s to 50°C / s, and the coiling is performed while the temperature is maintained at 650°C to 700°C.

[0021] Furthermore, the total cold rolling reduction rate is 57% to 65%.

[0022] Furthermore, during the hood annealing, the cold-rolled sheet is fed into a hood annealing furnace and preheated in a protective atmosphere of nitrogen or hydrogen mixture at a preheating temperature of 350±10°C. After preheating, annealing is performed at a temperature of 700±10°C, and then the temperature is lowered to room temperature.

[0023] Furthermore, the flattened elongation is 0.5% to 0.9%.

[0024] The beneficial effects of the present invention are:

[0025] 1. The wear-resistant cold-rolled sheet for cutting tools prepared by the present invention has good performance, which is not only attributed to the chemical composition of the cold-rolled sheet, but also to the preparation steps. The final yield strength is ≥260MPa, the tensile strength is ≥420MPa, the A50 elongation is ≥28%, the HRB hardness is 65-75, and it is strong and tough, and is suitable for manufacturing cutting tools, chains, etc.

[0026] 2. In the preparation method of the present invention, the annealing process makes the metallographic phase of the cold-rolled sheet consist of ferrite and pearlite, wherein the proportion of pearlite is ≥10%, mainly consisting of fine ferrite and a certain amount of pearlite, and dispersed precipitate phases can be seen in some areas, further enhancing the wear resistance of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the metallographic structure of the wear-resistant cold-rolled plate for cutting tools having both strength and toughness in Example 1 of the present invention. DETAILED DESCRIPTION

[0028] The method of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0029] The present invention provides a wear-resistant cold-rolled plate for cutting tools that is both strong and tough, and the chemical composition thereof is as follows by weight percentage:

[0030] C: 0.18%~0.24%, Si: 0.17%~0.35%, Mn: 0.80%~1.0%, P≤0.020%;

[0031] S≤0.020%, Cr: 0.10%~0.25%, Ni: 0.01%~0.05%, Cu: 0.05%~0.10%, and the balance is Fe and inevitable impurities.

[0032] C: As a major solid solution strengthening element, it aims to improve the strength, hardness and wear resistance of the material while maintaining appropriate toughness. In the present invention, the C percentage content is controlled within a range of 0.16% to 0.24%.

[0033] Si: helps to improve the corrosion resistance, heat resistance and strength of the material, especially performs well in an oxidizing environment. In the present invention, the Si percentage content is controlled in the range of 0.17% to 0.35%.

[0034] Mn: Manganese is a good deoxidizer and desulfurizer, which significantly improves the strength of the material through solid solution strengthening and precipitation strengthening mechanisms. Too high a content is not good for plasticity, welding performance, and fatigue performance. Considering comprehensively, the Mn percentage content in the present invention is controlled within the range of 0.80% to 1.0%.

[0035] P: Phosphorus has solid solution strengthening and cold work hardening effects in steel, which can improve the strength and atmospheric corrosion resistance of steel. However, phosphorus will reduce the plasticity and toughness of steel, causing the steel to be easily brittle during cold working. P is not good for welding wire forming and welding. Therefore, the P percentage content in the present invention is controlled within a range of ≤0.020%.

[0036] S: S reduces the ductility and toughness of steel, but will cause cracks during forming, affecting the drawing performance of the welding wire and also being detrimental to the welding performance of the welding wire. Therefore, the S percentage content in the present invention is controlled within a range of ≤0.020%.

[0037] Cr: Mainly used to improve the corrosion resistance and heat resistance of materials, especially in humid and corrosive environments. The Cr percentage content in the present invention is controlled within a range of 0.10% to 0.25%.

[0038] Ni: adding a proper amount helps to improve the strength, wear resistance and toughness of the material while maintaining good processing performance. The Ni percentage content in the present invention is controlled within the range of 0.01% to 0.05%.

[0039] Cu: As an auxiliary alloying element, adding a proper amount can further optimize the corrosion resistance and wear resistance of the material. In the present invention, the percentage of Cu is controlled within a range of 0.05% to 0.10%.

[0040] Preferably, the metallographic structure is ferrite and pearlite, and the proportion of pearlite is ≥10%.

[0041] The organization and performance of ferrite are similar to those of pure iron, with good plasticity and toughness, but low strength and hardness. As the carbon content in steel increases, the amount of ferrite decreases relatively, and the amount of pearlite increases. At this time, the ferrite is network-shaped and crescent-shaped. The cold-rolled sheet of the present invention belongs to medium carbon steel. The mechanical properties of pearlite are between ferrite and cementite, with high strength, moderate hardness, and certain plasticity. The comprehensive mechanical properties of pearlite are better than those of either ferrite or cementite alone. The mechanical properties of pearlite are between ferrite and cementite, with moderate strength and hardness, and are not brittle.

[0042] A method for processing a strong and tough wear-resistant cold-rolled plate comprises the following steps in sequence:

[0043] Smelting, continuous casting, hot rolling, pickling, cold rolling, annealing and leveling.

[0044] After cold rolling, the steel coil has its grains broken and elongated, and the lattice is seriously distorted, which increases the hardness of the steel and reduces the plasticity and toughness, that is, the work hardening phenomenon occurs. By heating it to above the recrystallization temperature and below the austenite transformation temperature, and keeping it warm for a certain period of time, the unstable atoms on the grain boundaries are rearranged due to thermal motion, and new equiaxed grains are formed through the process of nucleation and growth, that is, recrystallization occurs. As a result, the strength and hardness of the steel are reduced, and the plasticity and toughness are increased, so that the strip steel has good process and use performance. Recrystallization requires a certain time and temperature, but with the increase of temperature and excessive extension of time, the grain boundaries of the formed equiaxed grains will fuse, and the new equiaxed grains will continue to grow. This process will cause the various properties of the steel to decrease again. Therefore, recrystallization annealing can be summarized as: through heating and keeping warm, the steel after cold rolling should be recrystallized, while preventing its grains from growing excessively. As an important heat treatment method, the hood annealing process can uniformly anneal the cold-rolled sheet under a protective atmosphere and effectively improve the structure and properties of medium carbon steel.

[0045] Preferably, the smelting temperature is 1550° C. to 1600° C. The smelting is carried out under vacuum or inert gas protection, and the purity of the raw materials and the smelting temperature are strictly controlled to ensure uniform chemical composition.

[0046] Preferably, the continuous casting adopts tundish heating and electromagnetic stirring to control the temperature gradient of the ingot to ≤100°C / m to reduce internal defects, and the continuous casting speed is controlled to 0.8m / min to 1.2m / min to obtain an ingot with a smooth surface and a dense internal structure.

[0047] Preferably, the hot rolling temperature is 1150°C to 1200°C, and the total hot rolling reduction is ≥60% through multiple rolling passes, and a uniform plate shape and microstructure are obtained through multiple rolling passes. Furthermore, after hot rolling, cooling is performed, and the cooling rate is controlled to be 20°C / s to 50°C / s, and when cooled to 650°C to 700°C, this temperature is maintained for coiling.

[0048] Preferably, the hot-rolled plate is pickled after cooling to remove the surface iron oxide scale to ensure that the surface is clean before cold rolling.

[0049] Preferably, the total cold rolling reduction ratio is 55% to 65% to obtain the target thickness and cold working hardening effect.

[0050] Preferably, during the hood annealing, the cold-rolled sheet is fed into a hood annealing furnace and preheated in a protective atmosphere (such as a nitrogen and hydrogen mixture) to remove moisture and residual gas on the surface of the cold-rolled sheet. The preheating temperature is 350±10°C. After preheating, annealing is performed at a temperature of 700±10°C. The sheet is kept warm for a period of time (depending on the thickness and performance requirements of the cold-rolled sheet, generally 2-6 hours) to homogenize the internal structure of the cold-rolled sheet and precipitate a beneficial alloy phase. After annealing, the temperature is gradually lowered to room temperature to avoid excessive thermal stress inside the cold-rolled sheet.

[0051] Preferably, the cold-rolled sheet after annealing is flattened to improve the sheet shape and surface quality, and the flattening elongation is 0.5% to 1.0%.

[0052] The present invention is further illustrated by several specific examples and comparative examples below.

[0053] Example 1

[0054] A strong and tough wear-resistant cold-rolled plate for cutting tools, the chemical composition of which is calculated by weight percentage:

[0055] C: 0.18%, Si: 0.25%, Mn: 0.95%, P: 0.012%; S: 0.016%, Cr: 0.22%, Ni: 0.022%, Cu: 0.08%, and the balance is Fe and inevitable impurities.

[0056] The preparation process includes the following steps:

[0057] Smelting: According to the chemical composition of this embodiment, smelting is carried out under vacuum or inert gas protection, and the smelting temperature is 1580°C.

[0058] Continuous casting: Tundish heating and electromagnetic stirring are used, and the continuous casting speed is controlled at 1m / min to obtain the ingot.

[0059] Hot rolling: The ingot is heated to 1180℃ in a heating furnace for hot rolling. After multiple rolling passes, the final hot rolling total reduction rate is 60% to 70%. After hot rolling, rapid cooling is adopted, and the cooling rate is controlled at 30℃ / s. Then it is coiled, and the coiling temperature is controlled at 680℃.

[0060] Pickling: The hot-rolled plate is pickled after cooling to remove the surface oxide scale and ensure the surface is clean before cold rolling.

[0061] Cold rolling: cold rolling is carried out on a cold rolling mill, and the total cold rolling reduction rate is controlled to be 65%.

[0062] Hood annealing: The cold-rolled sheet is sent into a hood annealing furnace and preheated in a protective atmosphere (such as nitrogen and hydrogen mixture) at a preheating temperature of 350°C. After preheating, the furnace temperature is increased to the annealing temperature of 700°C and kept warm for 3 hours. After annealing, the furnace temperature is gradually reduced to room temperature.

[0063] Flattening: The cold rolled sheet after hooding is flattened, and the flattening elongation is 0.8%.

[0064] Example 2

[0065] A strong and tough wear-resistant cold-rolled plate for cutting tools, the chemical composition of which is calculated by weight percentage:

[0066] C: 0.22%, Si: 0.30%, Mn: 0.90%, P: 0.008%; S: 0.008%, Cr: 0.15%, Ni: 0.028%, Cu: 0.07%, and the balance is Fe and inevitable impurities.

[0067] The preparation process includes the following steps:

[0068] Smelting: According to the chemical composition of this embodiment, smelting is carried out under vacuum or inert gas protection, and the smelting temperature is 1595°C.

[0069] Continuous casting: Tundish heating and electromagnetic stirring are used, and the continuous casting speed is controlled at 0.9m / min to obtain the ingot.

[0070] Hot rolling: The ingot is heated to 1198℃ in a heating furnace for hot rolling. After multiple rolling passes, the final hot rolling total reduction rate is 60% to 70%. After hot rolling, rapid cooling is adopted, and the cooling rate is controlled at 46℃ / s. Then it is coiled, and the coiling temperature is controlled at 690℃.

[0071] Pickling: The hot-rolled plate is pickled after cooling to remove the surface oxide scale and ensure the surface is clean before cold rolling.

[0072] Cold rolling: cold rolling is carried out on a cold rolling mill, and the total cold rolling reduction rate is controlled to be 60%.

[0073] Hood annealing: The cold-rolled sheet is sent into a hood annealing furnace and preheated in a protective atmosphere (such as nitrogen and hydrogen mixture) at a preheating temperature of 342°C. After preheating, the furnace temperature is increased to the annealing temperature of 693°C and kept warm for 2.5 hours. After annealing, the furnace temperature is gradually reduced to room temperature.

[0074] Flattening: The cold rolled sheet after hooding is flattened, and the flattening elongation is 0.5%.

[0075] Example 3

[0076] A strong and tough wear-resistant cold-rolled plate for cutting tools, the chemical composition of which is calculated by weight percentage:

[0077] C: 0.20%, Si: 0.22%, Mn: 0.82%, P: 0.011%; S: 0.003%, Cr: 0.18%, Ni: 0.045%, Cu: 0.09%, and the balance is Fe and inevitable impurities.

[0078] The preparation process includes the following steps:

[0079] Smelting: According to the chemical composition of this embodiment, smelting is carried out under vacuum or inert gas protection, and the smelting temperature is 1570°C.

[0080] Continuous casting: Tundish heating and electromagnetic stirring are used, and the continuous casting speed is controlled at 1.1m / min to obtain ingots.

[0081] Hot rolling: The ingot is heated to 1172℃ in a heating furnace for hot rolling. After multiple rolling passes, the final hot rolling total reduction rate is 60% to 70%. After hot rolling, rapid cooling is adopted, and the cooling rate is controlled at 28℃ / s. Then it is coiled, and the coiling temperature is controlled at 667℃.

[0082] Pickling: The hot-rolled plate is pickled after cooling to remove the surface oxide scale and ensure the surface is clean before cold rolling.

[0083] Cold rolling: cold rolling is carried out on a cold rolling mill, and the total cold rolling reduction rate is controlled to be 57%.

[0084] Hood annealing: The cold-rolled sheet is sent into a hood annealing furnace and preheated in a protective atmosphere (such as nitrogen and hydrogen mixture) at a preheating temperature of 355°C. After preheating, the furnace temperature is increased to the annealing temperature of 704°C and kept warm for 4 hours. After annealing, the furnace temperature is gradually reduced to room temperature.

[0085] Flattening: The cold rolled sheet after hooding is flattened, and the flattening elongation is 0.9%.

[0086] Comparative Example 1

[0087] Compared with Example 1, the contents of Cr, Ni and Cu are reduced, and the specific components are as follows:

[0088] C: 0.18%, Si: 0.25%, Mn: 0.95%, P: 0.012%, S: 0.016%, Cr: 0.02%, Ni: 0.005%, Cu: 0.01%, and the balance is Fe and inevitable impurities.

[0089] The preparation process includes the following steps:

[0090] Smelting: According to the chemical composition of this embodiment, smelting is carried out under vacuum or inert gas protection, and the smelting temperature is 1580°C.

[0091] Continuous casting: Tundish heating and electromagnetic stirring are used, and the continuous casting speed is controlled at 1m / min to obtain the ingot.

[0092] Hot rolling: The ingot is heated to 1180℃ in a heating furnace for hot rolling. After multiple rolling passes, the final hot rolling total reduction rate is 60% to 70%. After hot rolling, rapid cooling is adopted, and the cooling rate is controlled at 30℃ / s. Then, the coiling is carried out, and the coiling temperature is controlled at 680℃. The total hot rolling reduction rate = 1-(hot rolled plate thickness after cooling / ingot thickness after initial heating in the heating furnace).

[0093] Pickling: The hot-rolled plate is pickled after cooling to remove the surface oxide scale and ensure the surface is clean before cold rolling.

[0094] Cold rolling: cold rolling is carried out on a cold rolling mill, and the total cold rolling reduction ratio is controlled to be 65%. The total cold rolling reduction ratio = 1-(final cold-rolled sheet thickness / hot-rolled sheet thickness after pickling).

[0095] Hood annealing: The cold-rolled sheet is sent into a hood annealing furnace and preheated in a protective atmosphere (such as nitrogen and hydrogen mixture) at a preheating temperature of 350°C. After preheating, the furnace temperature is increased to the annealing temperature of 700°C and kept warm for 5 hours. After annealing, the furnace temperature is gradually reduced to room temperature.

[0096] Flattening: The cold rolled sheet after hooding is flattened, and the flattening elongation is 0.8%.

[0097] Comparative Example 2

[0098] Comparative Example 2 is a common low-carbon aluminum killed steel cold-rolled plate, which has low strength and hardness and is difficult to meet the requirements. The specific composition is as follows:

[0099] C: 0.07%, Si: 0.03%, Mn: 0.30%, P: 0.010%; S: 0.012%, Cr: 0.01%, Ni: 0.009%, Cu: 0.01%, and the balance is Fe and inevitable impurities.

[0100] The preparation process includes the following steps:

[0101] Smelting: According to the chemical composition of this embodiment, smelting is carried out under vacuum or inert gas protection, and the smelting temperature is 1590°C.

[0102] Continuous casting: Tundish heating and electromagnetic stirring are used, and the continuous casting speed is controlled at 1m / min to obtain the ingot.

[0103] Hot rolling: The ingot is heated to 1200℃ in a heating furnace for hot rolling. After multiple rolling passes, the final hot rolling total reduction rate is 60% to 70%. After hot rolling, rapid cooling is adopted, and the cooling rate is controlled at 40℃ / s. Then it is coiled, and the coiling temperature is controlled at 700℃.

[0104] Pickling: The hot-rolled plate is pickled after cooling to remove the surface oxide scale and ensure the surface is clean before cold rolling.

[0105] Cold rolling: cold rolling is carried out on a cold rolling mill, and the total cold rolling reduction rate is controlled to be 75%.

[0106] Hood annealing: The cold-rolled sheet is sent into a hood annealing furnace and preheated in a protective atmosphere (such as nitrogen and hydrogen mixture) at a preheating temperature of 400°C. After preheating, the furnace temperature is increased to the annealing temperature of 650°C and kept warm for 1 hour. After annealing, the furnace temperature is gradually reduced to room temperature.

[0107] Flattening: The cold rolled sheet after hooding is flattened, and the flattening elongation is 1.8%.

[0108] Comparative Example 3

[0109] Comparative Example 3 is compared with Example 1, the chemical composition is the same, but the hot rolling and annealing parameters are different, and the specific composition is as follows:

[0110] C: 0.18%, Si: 0.25%, Mn: 0.95%, P: 0.012%; S: 0.016%, Cr: 0.22%, Ni: 0.022%, Cu: 0.08%, and the balance is Fe and inevitable impurities.

[0111] The preparation process includes the following steps:

[0112] Smelting: According to the chemical composition of this embodiment, smelting is carried out under vacuum or inert gas protection, and the smelting temperature is 1610°C.

[0113] Continuous casting: Tundish heating and electromagnetic stirring are used, and the continuous casting speed is controlled at 1.2m / min to obtain ingots.

[0114] Hot rolling: The ingot is heated to 1230℃ in a heating furnace for hot rolling. After multiple rolling passes, the final hot rolling total reduction rate is 60% to 70%. After hot rolling, rapid cooling is adopted, and the cooling rate is controlled at 10℃ / s. Then it is coiled, and the coiling temperature is controlled at 620℃.

[0115] Pickling: The hot-rolled plate is pickled after cooling to remove the surface oxide scale and ensure the surface is clean before cold rolling.

[0116] Cold rolling: cold rolling is carried out on a cold rolling mill, and the total cold rolling reduction rate is controlled to be 50%.

[0117] Hood annealing: The cold-rolled sheet is sent into a hood annealing furnace and preheated in a protective atmosphere (such as nitrogen and hydrogen mixture) at a preheating temperature of 300°C. After preheating, the furnace temperature is increased to the annealing temperature of 650°C without insulation. After annealing, the furnace temperature is gradually reduced to room temperature.

[0118] Flattening: The cold rolled sheet after hooding is flattened, and the flattening elongation is 0.4%.

[0119] Performance Analysis

[0120] The specific chemical compositions of each embodiment and comparative example are shown in Table 1:

[0121] Table 1 Chemical composition of cold rolled sheet (wt%)

[0122] C Si Mn P S Cr Ni Cu Example 1 0.18 0.25 0.95 0.012 0.016 0.22 0.022 0.08 Example 2 0.22 0.30 0.90 0.008 0.008 0.15 0.028 0.07 Example 3 0.20 0.22 0.82 0.011 0.003 0.18 0.045 0.09 Comparative Example 1 0.18 0.25 0.95 0.012 0.016 0.02 0.005 0.01 Comparative Example 2 0.07 0.03 0.30 0.010 0.012 0.01 0.009 0.01 Comparative Example 3 0.18 0.25 0.95 0.012 0.016 0.22 0.022 0.08

[0123] After continuous casting of molten steel, it is hot rolled, cold rolled, continuously annealed and leveled to produce strong and tough wear-resistant cold rolled plates. The main process parameters and final properties are shown in Table 2:

[0124] Table 2 Production process parameters and product performance

[0125]

[0126] like Figure 1 As shown in Table 2, the metallographic structure of Example 1 is ferrite + pearlite, the proportion of pearlite is 10% to 20%, and it is mainly composed of fine ferrite and a certain amount of pearlite. Dispersed precipitation phases can be seen in some areas, which further enhances the wear resistance of the material. As shown in Table 2, the wear-resistant cold-rolled plate for tools with both strength and toughness of the present invention has a yield strength of ≥260MPa, a tensile strength of ≥420MPa, an A50 elongation of ≥28%, an HRB hardness of 65 to 75, and is both strong and tough, and is suitable for manufacturing tools, chains, etc.

[0127] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A strong and tough wear-resistant cold-rolled plate for cutting tools, characterized in that: Its chemical composition by weight percentage is: C: 0.18%~0.24%, Si: 0.17%~0.35%, Mn: 0.80%~1.0%, P≤0.020%; S≤0.020%, Cr: 0.10%~0.25%, Ni: 0.01%~0.05%, Cu: 0.05%~0.10%, and the balance is Fe and inevitable impurities.

2. The wear-resistant cold-rolled sheet for cutting tools having both strength and toughness according to claim 1, characterized in that: The metallographic structure of the cold-rolled sheet is ferrite and pearlite, and the proportion of pearlite is 10% to 20%.

3. A method for processing the strong and tough wear-resistant cold-rolled sheet for cutting tools according to claim 1 or 2, characterized in that: The following steps are included in sequence: Smelting, continuous casting, hot rolling, pickling, cold rolling, annealing, and leveling; among which: The smelting temperature is 1550°C to 1600°C; The continuous casting adopts tundish heating and electromagnetic stirring, controls the temperature gradient to be ≤120°C / m, and controls the continuous casting speed to be 0.8m / min-1.2m / min; The hot rolling temperature is 1150°C to 1200°C, and the total hot rolling reduction ratio is ≥ 60%; The total cold rolling reduction rate is 55% to 65%; The hood annealing is to put the cold rolled sheet into a hood annealing furnace, preheat it under a protective atmosphere, anneal it after preheating, and cool it to room temperature after annealing. The flattening elongation is 0.5% to 1.0%.

4. The method for processing the strong and tough wear-resistant cold-rolled sheet for cutting tools according to claim 3, characterized in that: The smelting temperature is 1570°C to 1595°C.

5. The method for processing the strong and tough wear-resistant cold-rolled sheet for cutting tools according to claim 3, characterized in that: The continuous casting adopts tundish heating and electromagnetic stirring, controls the temperature gradient to be ≤100°C / m, and controls the continuous casting speed to be 0.9m / min-1.1m / min.

6. The method for processing the strong and tough wear-resistant cold-rolled sheet for cutting tools according to claim 3, characterized in that: The hot rolling temperature is 1172° C. to 1198° C., and the total hot rolling reduction ratio is ≥60% to 70%.

7. The method for processing the strong and tough wear-resistant cold-rolled sheet for cutting tools according to claim 6, characterized in that: After hot rolling, the steel is cooled at a cooling rate of 20°C / s to 50°C / s. When the steel is cooled to 650°C to 700°C, this temperature is maintained for coiling.

8. The method for processing the strong and tough wear-resistant cold-rolled sheet for cutting tools according to claim 3, characterized in that: The total cold rolling reduction rate is 57% to 65%.

9. The method for processing the strong and tough wear-resistant cold-rolled sheet for cutting tools according to claim 3, characterized in that: During the hood annealing, the cold rolled sheet is sent into a hood annealing furnace, preheated in a protective atmosphere of nitrogen or hydrogen mixed gas, the preheating temperature is 350±10°C, annealed after preheating, the annealing temperature is 700±10°C, and then cooled to room temperature after annealing.

10. The method for processing the strong and tough wear-resistant cold-rolled sheet for cutting tools according to claim 3, characterized in that: The flattened elongation is 0.5% to 0.9%.

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