High fatigue performance bimetallic saw blade backing steel and production method thereof

Abstract

The present application provides a high fatigue performance bimetallic saw blade backing steel and a production method thereof. The high fatigue performance bimetallic saw blade backing steel includes the following components in percentage by mass: C: 0.30-0.35%, Cr: 3.00-3.25%, Ni: 0.25-1.00%, Mo: 1.80-2.25%, Si: 0.30-0.50%, Mn: 0.60-1.00%, V: 0.30-0.50%; the rest is Fe and unavoidable impurities. The present application uses a medium-low carbon content to ensure that the steel has high plasticity and toughness by adjusting the element components and their contents in the bimetallic saw blade backing steel; at the same time, a higher content of Cr and Mo elements is used, wherein Mo can improve the strength and tempering stability of the steel, and the precipitated carbides of the Cr element during the tempering process play a pinning role on the grain boundaries and subgrain boundaries, effectively improving the strength of the steel, and cooperating with other chemical components to work together to produce a bimetallic saw blade backing steel with excellent fatigue performance.

Description

Technical Field

[0001] The present application relates to the technical field of steel preparation, and in particular to a high fatigue performance bimetallic saw blade backing steel and a production method thereof. Background Art

[0002] Band saw blades are a common cutting tool. They are known as the "hands of craftsmen" because of their excellent red-hard cutting performance, good cutting quality, and high precision. Currently, among all types of band saw blades, bimetallic band saw blades are the most widely used. Therefore, the development and research of backing materials has always been an important way to improve the comprehensive performance of bimetallic band saw blades. The backing materials of bimetallic band saw blades are generally spring steel and high-strength steel with high strength, excellent toughness and good fatigue resistance.

[0003] At present, there are few types and specifications of steel suitable for bimetallic band saw blade backing. On the other hand, the final heat treatment of bimetallic band saw blade backing requires high temperature quenching and three high temperature tempering, which easily leads to its coarsening and poor fatigue resistance of backing steel. Most of the failure mechanisms of existing bimetallic band saw blades are early fatigue fracture of backing steel. Therefore, the development of a high fatigue performance backing steel and its production method is a key technical problem to be solved in the domestic sawing industry. Summary of the invention

[0004] The embodiments of the present application provide a high fatigue performance bimetallic saw blade backing steel and a production method thereof, aiming to improve its fatigue performance.

[0005] In the first aspect, an embodiment of the present application provides a high fatigue performance bimetallic saw blade backing steel, comprising the following components in percentage by mass: C: 0.30-0.35%, Cr: 3.00-3.25%, Ni: 0.25-1.00%, Mo: 1.80-2.25%, Si: 0.30-0.50%, Mn: 0.60-1.00%, V: 0.30-0.50%; the rest is Fe and unavoidable impurities.

[0006] According to an embodiment of the first aspect of the present application, the mass percentage of Cr is 3.05-3.20%.

[0007] According to an embodiment of the first aspect of the present application, the mass percentage of Mo is 1.85-2.10%.

[0008] According to the embodiment of the first aspect of the present application, the yield strength of the steel used for the back material of the high fatigue performance bimetallic saw blade is 1100MPa~1250MPa, the tensile strength is 1500MPa~1650MPa, the elongation is 12%~15%, and the torsional fatigue number is ≥6250 times.

[0009] In a second aspect, the present application provides a method for producing high fatigue performance bimetallic saw blade backing steel, comprising the following steps:

[0010] Continuously casting to obtain a cast ingot, the cast ingot includes the following components in percentage by weight: C: 0.30-0.35%, Cr: 3.00-3.25%, Ni: 0.25-1.00%, Mo: 1.80-2.25%, Si: 0.30-0.50%, Mn: 0.60-1.00%, V: 0.30-0.50%; the rest is Fe and unavoidable impurities;

[0011] The ingot is subjected to heating in a heating furnace, rough rolling, hot coil box, finishing rolling, laminar cooling, coiling and slow cooling treatment to obtain high fatigue performance bimetallic saw blade back material steel.

[0012] According to an embodiment of the second aspect of the present application, the heating treatment in the heating furnace includes: the entry temperature of the ingot into the heating furnace is above 400°C, and the ingot is heated to above 1200°C in the heating furnace.

[0013] According to an embodiment of the second aspect of the present application, the finishing rolling process includes: the initial hot rolling temperature is controlled at 860-940°C, and the final hot rolling temperature is controlled at 890-920°C.

[0014] According to an embodiment of the second aspect of the present application, the temperature of the coiling process is controlled at 650-750°C.

[0015] According to an embodiment of the second aspect of the present application, in the step of continuous casting to obtain a cast ingot, the superheat is 15 to 35° C. and the pulling speed is 0.6 to 1.5 m / min.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] The present application adjusts the element components and their contents in the bimetallic saw blade backing steel so that C, Cr, Mo and other chemical components work together to produce a bimetallic saw blade backing steel with excellent fatigue performance.

[0018] The components of the present application use medium and low carbon content to ensure that the steel has high plasticity and toughness; at the same time, a high content of Cr and Mo elements is used, wherein Mo can improve the strength and tempering stability of the steel. It can exist in the solid solution and carbide in the steel, especially in the alloy carbide, and play a role in solid solution strengthening, thereby improving the strength of the steel, and in the high temperature tempering process, a special carbide dispersedly distributed in the organization is formed, and the carbide has a secondary hardening effect, which is beneficial to improving the ductility, toughness and wear resistance of the steel; the Cr element has a strong affinity with carbon, and can precipitate (Fe, Cr) during the tempering process. 23 C6 Cr 23 C 6 Carbides such as Cr can pin the grain boundaries and subgrain boundaries, effectively improving the strength of the steel. At the same time, Cr can improve the tempering stability of the steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0020] Figure 1 This is a microstructure diagram of the high fatigue performance bimetallic saw blade backing steel of Example 1 of the present application;

[0021] Figure 2 This is a microstructure diagram of the steel used for the high fatigue performance bimetallic saw blade backing material in Example 2 of the present application. DETAILED DESCRIPTION

[0022] The following detailed description and drawings of the embodiments of the present application are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0023] In the description of the present application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating the orientation or positional relationship are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" does not require verticality in the strict sense, but may include allowable errors. "Parallel" does not require parallelism in the strict sense, but may include allowable errors.

[0024] At present, there are still few steel types developed for bimetallic band saw blade backing in China, which has led to the domestic high-end band saw blade market being monopolized by foreign brands. The existing bimetallic band saw blade backing is generally made of Cr-Ni-Mo-V alloy tool steel through a complex processing process. Researching and developing a backing steel with excellent performance is of great significance to improving the technical level and market competitiveness of the entire industry in my country.

[0025] In view of this, the inventors of the present application, after a large number of experimental studies, provide a high fatigue performance bimetallic saw blade backing steel and a production method thereof, aiming to improve its fatigue performance.

[0026] High fatigue performance bimetallic saw blade backing steel

[0027] In the first aspect, an embodiment of the present application provides a high fatigue performance bimetallic saw blade backing steel, comprising the following components in percentage by mass: C: 0.30-0.35%, Cr: 3.00-3.25%, Ni: 0.25-1.00%, Mo: 1.80-2.25%, Si: 0.30-0.50%, Mn: 0.60-1.00%, V: 0.30-0.50%; the rest is Fe and unavoidable impurities.

[0028] The components of the present application use medium and low carbon content to ensure that the steel has high plasticity and toughness; at the same time, a high content of Cr and Mo elements is used, wherein Mo can improve the strength and tempering stability of the steel. It can exist in the solid solution and carbide in the steel, especially in the alloy carbide, and play a role in solid solution strengthening, thereby improving the strength of the steel, and in the high temperature tempering process, a special carbide dispersedly distributed in the organization is formed, and the carbide has a secondary hardening effect, which is beneficial to improving the ductility, toughness and wear resistance of the steel; the Cr element has a strong affinity with carbon, and can precipitate (Fe, Cr) during the tempering process. 23 C 6 Cr 23 C 6 Carbides such as Cr can pin the grain boundaries and subgrain boundaries, effectively improving the strength of the steel. At the same time, Cr can improve the tempering stability of the steel.

[0029] Next, the role of each chemical component of the high fatigue performance bimetallic saw blade backing steel is described in detail:

[0030] C: Carbon is a basic element in steel. It is an austenite-forming element and also a strengthening element for martensite and ferrite. The increase of carbon content significantly increases the hardness of steel while reducing its plasticity and toughness. In alloy steel, carbon can form M with alloying elements such as Cr, Mo, and V in steel. 23 C 6 、M 6 C.M. 2 If various types of carbides such as C can be distributed in a fine and dispersed manner, the grains can be refined and precipitation strengthening can be produced, thereby improving the strength and toughness of the material.

[0031] The present application controls the C content within the medium-low carbon range, which ensures the plastic toughness of the steel on the one hand, and on the other hand, has enough carbon to form Cr, Mo, and V carbides, which is beneficial to the improvement of fatigue performance. For example, the mass percentage of the C element is 0.30%, 0.31%, 0.32%, 0.33%, or 0.34%.

[0032] Cr: significantly improves the hardenability and tempering stability of steel, ensuring the high-temperature tempering heat treatment process performance of the bimetallic band saw blade backing material; Cr can significantly increase the tough-brittle transition temperature of steel and improve the wear resistance of steel. During the tempering process, it combines with carbon to precipitate (Fe, Cr) 23 C 6 Cr 23 C 6 Carbides such as ferrites play a pinning role on grain boundaries.

[0033] The present application controls the Cr content within a relatively high range to ensure the tempering stability of the steel, a high ductile-brittle transition temperature, and improve the brittle fracture resistance of the bimetallic band saw blade. For example, the mass percentage of the Cr element is 3.00%, 3.02%, 3.04%, 3.06%, 3.08%, 3.10%, 3.12%, 3.14%, 3.16%, 3.18%, 3.20%, 3.22% or 3.25%.

[0034] Ni: Nickel and iron can be infinitely dissolved, strengthening ferrite and refining pearlite, which can significantly improve the toughness of steel; Ni improves the fatigue performance of steel and reduces the sensitivity of steel to notches. When used together with Cr and Mo to form nickel-chromium or nickel-chromium-molybdenum steel, it can obtain comprehensive mechanical properties with good combination of strength and toughness after heat treatment.

[0035] A certain amount of Ni is added to the steel of the present application, which is beneficial to its comprehensive performance. For example, the mass percentage of the Ni element is 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, 0.50%, 0.55%, 0.60%, 0.65%, 0.70%, 0.75%, 0.80%, 0.85%, 0.90%, 0.95% or 1.00%.

[0036] Mo: The most obvious effect of molybdenum is to improve the tempering stability of steel. When it coexists with chromium, manganese, etc., molybdenum inhibits the tempering brittleness caused by other elements. In addition, Mo has a solid solution strengthening effect on ferrite, and also improves the stability of carbides, thereby increasing the strength of steel. Molybdenum plays a beneficial role in improving the ductility, toughness and wear resistance of steel.

[0037] In the present application, the content of Mo in the steel used as the backing material of the bimetallic saw blade is increased to a certain range, mainly for the high quenching and high tempering heat treatment of the bimetallic band saw blade, which easily causes the steel to form an overheated structure, especially the tempering temperature is under the high temperature tempering brittleness, so the role of Mo in inhibiting tempering brittleness is extremely important in the steel used as the backing material of the bimetallic band saw blade. Exemplarily, the mass percentage of the Mo element is 1.80%, 1.82%, 1.85%, 1.88%, 1.90%, 1.95%, 2.00%, 2.05%, 2.10%, 2.15%, 2.20% or 2.25%.

[0038] Mn: Manganese is solid-dissolved in ferrite and austenite, which has a significant solid-solution strengthening effect and improves hardenability. It can also form MnS with a higher melting point with sulfur in steel, which is beneficial to eliminate the hot brittleness of steel. However, Mn can easily cause grain growth and temper brittleness when the steel is overheated.

[0039] The steel of the present invention controls the content of Mn in a relatively low range, mainly based on the deoxidation residue during the steelmaking process, mainly considering that Mn easily causes overheating of the steel, and at the same time adds a trace amount of V that can refine the grains to offset the negative effects of Mn. Exemplarily, the mass percentage of the Mn element is 0.60%, 0.65%, 0.70%, 0.75%, 0.80%, 0.85%, 0.90%, 0.95% or 1.00%.

[0040] V: Since vanadium and carbon can form stable and refractory carbides, the steel can maintain a fine-grained structure at higher temperatures, greatly reducing the overheating sensitivity of the steel. The dispersed VC carbides can improve the hardness and wear resistance of tool steel.

[0041] The steel of the present invention adds a small amount of V for microalloying, and its fine grain structure and reduced overheating sensitivity of the steel all play a positive role in improving the fatigue performance of the bimetallic band saw blade. Exemplarily, the mass percentage of the V element is 0.30%, 0.32%, 0.34%, 0.36%, 0.38%, 0.40%, 0.42%, 0.44%, 0.46%, 0.48% or 0.50%.

[0042] In summary, the present application adjusts the elemental components and their contents in the bimetallic saw blade backing steel, and the chemical components work together to produce bimetallic saw blade backing steel with excellent fatigue performance. The bimetallic saw blade backing steel provided by the present application can be used in the field of sawing steel manufacturing.

[0043] Production method for high fatigue performance bimetallic saw blade backing steel

[0044] In a second aspect, an embodiment of the present application provides a method for producing high fatigue performance bimetallic saw blade backing steel, comprising: continuously casting molten steel to obtain a cast ingot; the cast ingot comprises the following components in percentage by mass: C: 0.30-0.35%, Cr: 3.00-3.25%, Ni: 0.25-1.00%, Mo: 1.80-2.25%, Si: 0.30-0.50%, Mn: 0.60-1.00%, V: 0.30-0.50%; the rest is Fe and unavoidable impurities;

[0045] The ingot is subjected to heating in a heating furnace, rough rolling, hot coil box, finishing rolling, laminar cooling, coiling and slow cooling treatment to obtain high fatigue performance bimetallic saw blade back material steel.

[0046] The production process of the bimetallic band saw blade backing steel of the present invention is mainly as follows:

[0047] Converter smelting → ladle furnace → vacuum furnace → slab continuous casting → heating in heating furnace → rough rolling → hot coil box → finishing rolling → laminar cooling → coiling → slow cooling.

[0048] Converter smelting: put molten iron, scrap steel, nickel-iron alloy and molybdenum-iron alloy into the converter, use the top and bottom double-blown converter for smelting, the smelting time is 30-50 minutes, the tapping temperature is 1600-1700°C, the mass percentage of the end point carbon is controlled to be 0.04-0.10%, silicon-iron alloy, manganese-iron alloy and aluminum-iron alloy are added for deoxidation when the molten steel is tapped, chromium-iron alloy is added for alloying, lime is added for slagging, and carbon powder is added for carbon increase;

[0049] Ladle furnace refining: add lime to make slag, add ferromanganese alloy, ferrosilicon alloy, ferrochrome alloy, ferromolybdenum alloy, ferronickel alloy and aluminum particles into LF refining furnace, add lime and pre-melted slag to make slag and desulfurize in LF refining furnace, add ferrovanadium alloy, adjust the temperature to 1570℃~1620℃ before leaving the station;

[0050] Vacuum furnace refining: Use extreme vacuum in RH or VD vacuum furnace for 10min to 20min to dehydrogenate and remove inclusions. At the end of RH or VD vacuum furnace smelting, increase the pressure to 10KPa to 40KPa, and blow nitrogen to carry out nitrogen alloying of molten steel, and control the nitrogen content to be above 0.02%;

[0051] Slab continuous casting: Slab continuous casting machine is used for casting, the superheat is controlled at 15℃~35℃, and the casting speed is 0.6m / min~1.5m / min;

[0052] Heating in heating furnace: The continuous casting slab adopts hot charging and hot delivery process to ensure that the slab temperature entering the heating furnace is above 400℃ and the slab heating temperature is above 1200℃;

[0053] In this temperature range, the phase structure in the ingot can be homogenized, which is conducive to fine grains and can eliminate the component segregation produced during the solidification process of the ingot to a certain extent.

[0054] Rough rolling and hot coil box: After rough rolling, the intermediate billet is put into the hot coil box for rolling;

[0055] Finishing rolling: The hot rolling final rolling temperature is controlled at 860-940℃, and the hot rolling final rolling temperature is controlled at 890-920℃.

[0056] The final rolling temperature of the finishing rolling is controlled within the above range. A final rolling temperature higher than 920°C is not conducive to the formation of M by elements such as Cr, Mo, and V. 23 C 6 、M 6 C.M. 2C is finely dispersed and precipitated, and it is easy to make the grains grow. Hot rolling within the above temperature range can obtain the final product that meets the requirements of excellent performance quality.

[0057] Laminar cooling: sparse cooling is used for laminar cooling after rolling;

[0058] Coiling: The coiling temperature is controlled at 650-750℃;

[0059] In this application, the coiling temperature is controlled at 650-750°C because the phase precipitation particles at this coiling temperature are dispersed and can provide a good precipitation strengthening effect to ensure the yield strength of the steel. If the coiling temperature is too high, the proportion of ferrite grains increases and the tensile strength is difficult to ensure. If the coiling temperature is too low, it is easy to cause coiling difficulties, and the steel plate has a large internal stress, which is not conducive to improving impact toughness.

[0060] Slow cooling: After rolling, the steel coil is quickly rolled off the production line and enters a slow cooling pit or slow cooling hood for slow cooling.

[0061] The slow cooling method is beneficial to reduce the internal stress of the ingot, alleviate the center segregation and center porosity of the ingot, and thus improve the plastic toughness.

[0062] Example

[0063] The following examples more specifically describe the disclosure of the present application, which are intended for illustrative purposes only, as it will be apparent to those skilled in the art that various modifications and variations are possible within the scope of the disclosure of the present application. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0064] Embodiment 1:

[0065] 190 tons of molten iron, 20 tons of scrap steel, 1.35 tons of ferronickel and 7.8 tons of ferromolybdenum were loaded into a 210-ton converter, and the top and bottom double-blown converter was used for smelting. 2 Bottom blowing was carried out, and the steel was tapped after 35 minutes of smelting. The final carbon content was 0.07%, and the tapping temperature was 1622°C. 6.1 tons of ferrochrome and 380 kg of carbon powder were added during tapping.

[0066] The molten steel is refined in a ladle furnace by a LF refining furnace, and lime is added to make slag. Ferromanganese alloy, ferrosilicon alloy, ferrochrome alloy, ferromolybdenum alloy, ferronickel alloy and aluminum particles are added to the LF refining furnace. Lime and pre-melted slag are added to the LF refining furnace for slagging and desulfurization. The mass percentages of C, Si, Mn, Ni, Cr, Mo and Al elements are adjusted to the target values: C: 0.32%, Si: 0.35%, Mn: 0.68%, Cr: 3.2%, Ni: 0.3%, Mo: 2.0%. After the content of each element is adjusted to the right level, ferrovanadium alloy is added to adjust the V content to the target content of 0.35%, and the steel is shipped out at 1581℃.

[0067] The molten steel is then subjected to a RH refining furnace, subjected to a 67Pa extreme vacuum treatment for 15 minutes, and a 300KPa nitrogen blowing treatment for 22 minutes, to control the nitrogen content of the molten steel to 0.025%.

[0068] The molten steel is cast into ingots through a continuous casting machine. The chemical composition of the ingots is as follows by weight: C: 0.31%, Si: 0.33%, Mn: 0.64%, Cr: 3.13%, V: 0.34%, Ni: 0.28%, Mo: 1.85%, and the rest is Fe and unavoidable impurities.

[0069] The thickness of the ingot is 230mm, and it is rolled into a steel coil with a specification of 3.0mm×1250mm on a 2250mm conventional hot rolling production line. The heating temperature is 1240℃, the thickness of the intermediate billet is 40mm, the final rolling temperature is 900℃, and after rolling, it is laminar cooled to the target coiling temperature of 720℃. After the steel coil is coiled, it is hoisted into a slow cooling hood for cooling.

[0070] The high fatigue performance bimetallic band saw blade backing steel produced according to the above production method has a strip thickness fluctuation of ≤±0.06mm, a convexity of ≤40μm, and a hardness difference of ≤6.0HRC in the same roll.

[0071] Embodiment 2:

[0072] 189 tons of molten iron, 21 tons of scrap steel, 1.35 tons of ferronickel and 7.8 tons of ferromolybdenum were loaded into a 210-ton converter and smelted in a top-bottom double-blown converter. The steel was tapped after 32 minutes of smelting, with an end point carbon content of 0.05% and a tapping temperature of 1621°C. 6.1 tons of low-carbon ferrochrome and 380 kg of carbon powder were added during tapping.

[0073] The molten steel is refined in a ladle furnace by an LF refining furnace, and lime is added to make slag. Ferromanganese alloy, ferrosilicon alloy, ferrochrome alloy, ferromolybdenum alloy, ferronickel alloy and aluminum particles are added to the LF refining furnace. Lime and pre-melted slag are added to the LF refining furnace for slagging and desulfurization. The mass percentages of C, Si, Mn, Ni, Cr, Mo and Al elements are adjusted to the target values: C: 0.32%, Si: 0.35%, Mn: 0.68%, Cr: 3.2%, Ni: 0.3%, Mo: 2.0%. After the contents of each alloy are adjusted, ferrovanadium alloy is added to adjust the V content to the target content of 0.35%, and the steel is shipped out at 1569℃.

[0074] The molten steel is then subjected to a RH refining furnace, subjected to a 67Pa extreme vacuum treatment for 15 minutes, and a 280KPa nitrogen blowing treatment for 25 minutes, to increase the nitrogen content of the molten steel to 0.031%.

[0075] The molten steel is poured into ingots through a continuous casting machine. The chemical composition of the ingots is as follows: C: 0.30%, Si: 0.35%, Mn: 0.65%, Cr: 3.09%, V: 0.36%, Ni: 0.32%, Mo: 2.02%, and the rest is Fe and unavoidable impurities.

[0076] The thickness of the ingot is 230mm, and it is rolled into a 4.0mm×1250mm steel coil on a 2250mm conventional hot rolling production line. The heating temperature is 1250℃, the thickness of the intermediate billet is 38mm, the final rolling temperature is 900℃, and after rolling, it is laminar cooled to the target coiling temperature of 700℃. After the steel coil is coiled, it is hoisted into a slow cooling hood for cooling.

[0077] The bimetallic band saw blade backing steel produced according to the above production method has a thickness fluctuation of ≤±0.06mm, a convexity of ≤40μm, and a hardness difference of ≤5.0HRC in the same roll.

[0078] Example 3

[0079] A high fatigue performance bimetallic saw blade backing steel has a preparation process similar to that of Example 1, except that the mass percentages of C, Si, Mn, Ni, Cr, Mo, and Al elements are adjusted to target values: C: 0.32%, Si: 0.35%, Mn: 0.68%, Cr: 3.2%, Ni: 0.3%, Mo: 2.0%, and after the contents of each alloy are adjusted in place, vanadium-iron alloy is added to adjust the V content to the target content of 0.35%, and the steel is shipped out at 1569°C.

[0080] The chemical composition of the ingot is as follows: C: 0.31%, Si: 0.32%, Mn: 0.65%, Cr: 3.09%, V: 0.36%, Ni: 0.32%, Mo: 2.02%, and the rest is Fe and unavoidable impurities.

[0081] Example 4

[0082] A high fatigue performance bimetallic saw blade backing steel has a preparation process similar to that of Example 1, except that the mass percentages of C, Si, Mn, Ni, Cr, Mo, and Al elements are adjusted to target values: C: 0.32%, Si: 0.35%, Mn: 0.68%, Cr: 3.2%, Ni: 0.3%, Mo: 2.0%, and after the contents of each alloy are adjusted in place, vanadium-iron alloy is added to adjust the V content to the target content of 0.35%, and the steel is shipped out at 1569°C.

[0083] The chemical composition of the ingot is as follows: C: 0.31%, Si: 0.32%, Mn: 0.65%, Cr: 3.09%, V: 0.36%, Ni: 0.32%, Mo: 2.02%, and the rest is Fe and unavoidable impurities.

[0084] Comparative Example 1

[0085] A steel material, the preparation process of which is similar to that of Example 1, except that the mass percentages of C, Si, Mn, Ni, Cr, Mo and Al elements are adjusted to target values ​​respectively: C: 0.32%, Si: 0.35%, Mn: 0.68%, Cr: 3.4%, Ni: 0.3%, Mo: 2.0%, and after the contents of each alloy are adjusted in place, vanadium-iron alloy is added to adjust the V content to the target content of 0.35%, and the steel material is shipped out at 1569°C.

[0086] The chemical composition of the ingot is as follows: C: 0.31%, Si: 0.32%, Mn: 0.65%, Cr: 3.35%, V: 0.36%, Ni: 0.32%, Mo: 2.02%, and the rest is Fe and unavoidable impurities.

[0087] Comparative Example 2

[0088] A steel material, the preparation process of which is similar to that of Example 1, except that the mass percentages of C, Si, Mn, Ni, Cr, Mo and Al elements are adjusted to target values ​​respectively: C: 0.32%, Si: 0.35%, Mn: 0.68%, Cr: 3.2%, Ni: 0.3%, Mo: 1.8%, and after the contents of each alloy are adjusted in place, vanadium-iron alloy is added to adjust the V content to the target content of 0.35%, and the steel material is shipped out at 1569°C.

[0089] The chemical composition of the ingot is as follows: C: 0.31%, Si: 0.32%, Mn: 0.65%, Cr: 3.09%, V: 0.36%, Ni: 0.32%, Mo: 1.68%, and the rest is Fe and unavoidable impurities.

[0090] Comparative Example 3

[0091] A steel material, the preparation process of which is similar to that of Example 1, except that the coiling temperature is adjusted to 800°C.

[0092] Comparative Example 4

[0093] A steel material, the preparation process of which is similar to that of Example 1, except that the steel material is heated to 1150° C. for rolling.

[0094] The high fatigue performance bimetallic saw blade backing steel obtained in Examples 1 to 4 and the products of Comparative Examples 1 to 4 were tested according to GB / T 228.1-2010; the torsional fatigue life was tested according to the torsional fatigue testing machine test method developed by the enterprise, with the fatigue stress set to 380 MPa and the frequency set to 1 Hz. The products prepared in the Examples and Comparative Examples were tested; the results are shown in Table 1.

[0095] Table 1 List of mechanical properties and tissue testing results of Examples 1-4 and Comparative Examples 1-4

[0096]

[0097]

[0098] As can be seen from Table 1, the high fatigue performance bimetallic saw blade backing material steels of Examples 1-4 have high strength, good plasticity and toughness, and especially excellent fatigue resistance. This indicates that the combination of the chemical composition ratio and the preparation process provided in this application can effectively make the obtained high fatigue performance bimetallic saw blade backing material steel have good mechanical properties and fatigue performance.

[0099] See also Figure 1 The bimetallic band saw blade backing steel produced according to the above production method has a tempered troostite microstructure, in which carbides are finely dispersedly distributed, which refines the grains and produces precipitation strengthening, thereby improving the strength and toughness of the material.

[0100] See also Figure 2 The bimetallic band saw blade backing steel produced according to the above production method has a tempered troostite microstructure, in which carbides are finely dispersedly distributed, which refines the grains and produces precipitation strengthening, thereby improving the strength and toughness of the material.

[0101] In comparative example 1, the Cr element content exceeds the range, resulting in high strength and hardness of the steel, and reduced plasticity and fatigue properties. In comparative example 2, the Mo element content exceeds the range, resulting in a significant increase in cost. In comparative example 3, the coiling temperature is too high, resulting in coarse grains of the raw material, which are then inherited to the finished product and reduce plasticity and toughness. In comparative example 4, the heating temperature is low, resulting in coarse carbides of the steel and obvious segregation, which greatly reduces plasticity and toughness.

[0102] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A high fatigue performance bimetallic saw blade backing steel, characterized in that: The invention comprises the following components in percentage by mass: C: 0.30-0.35%, Cr: 3.00-3.09%, Ni: 0.32-1.00%, Mo: 2.02-2.25%, Si: 0.30-0.35%, Mn: 0.60-0.65%, V: 0.36-0.50%; The rest is Fe and unavoidable impurities; The high fatigue performance bimetallic saw blade backing material steel has a yield strength of 1100MPa-1191MPa, a tensile strength of 1500MPa-1650MPa, an elongation of 12.4%-15%, and a torsional fatigue number of ≥6250 times.

2. A method for producing high fatigue performance bimetallic saw blade backing steel, characterized in that: include: Continuously casting to obtain a cast billet, wherein the cast billet includes the following components in percentage by mass: C: 0.30-0.35%, Cr: 3.00-3.09%, Ni: 0.32-1.00%, Mo: 2.02-2.25%, Si: 0.30-0.35%, Mn: 0.60-0.65%, V: 0.36-0.50%; The rest is Fe and unavoidable impurities; The ingot is subjected to heating in a heating furnace, rough rolling, hot coil box, finishing rolling, laminar cooling, coiling and slow cooling treatment to obtain a high fatigue performance bimetallic saw blade back material steel; The heating furnace heating treatment includes: the furnace entry temperature of the cast billet when entering the heating furnace is above 400° C., and the cast billet is heated to above 1200° C. in the heating furnace; The finishing rolling process includes: the initial hot rolling temperature is controlled at 860-940°C, and the final hot rolling temperature is controlled at 890-920°C; The high fatigue performance bimetallic saw blade backing material steel has a yield strength of 1100MPa-1191MPa, a tensile strength of 1500MPa-1650MPa, an elongation of 12.4%-15%, and a torsional fatigue number of ≥6250 times.

3. The method for producing high fatigue performance bimetallic saw blade backing steel according to claim 2, characterized in that: The temperature of the coiling process is controlled at 650-750°C.

4. The method for producing high fatigue performance bimetallic saw blade backing steel according to claim 2, characterized in that: In the step of continuously casting to obtain the ingot, the superheat degree is 15-35° C. and the pulling speed is 0.6-1.5 m / min.

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