CN117512442A

CN117512442A - Steel for ultrahigh-hardness saw blade and manufacturing method thereof

Info

Publication number: CN117512442A
Application number: CN202210914297.7A
Authority: CN
Inventors: 李红斌; 华蔚; 丁建华; 施青; 鲁岩; 沈燕
Original assignee: Baoshan Iron and Steel Co Ltd
Current assignee: Baoshan Iron and Steel Co Ltd
Priority date: 2022-07-29
Filing date: 2022-07-29
Publication date: 2024-02-06

Abstract

The present disclosure relates to steel for saw blades and a method of manufacturing the same. The steel for the saw blade comprises the following chemical elements in percentage by mass: c:0.76-0.90%, si:0.10-0.60%, mn:0.20-0.80%, cr:0.20-1.00%, V:0.05-0.50%, al:0.010-0.050%, ti:0.005-0.080%, ca:0.0010 to 0.0040% and is selected from Mo:0.10-0.50%, ni:0.50-1.50%, cu:0.20-0.60% and RE:0.01-0.08%, and the balance of Fe and unavoidable impurities. The steel for saw blade of the present disclosure has ultra-high strength (Rockwell hardness 50-60HRC, room temperature impact toughness kv2 of 30-60J) and uniform hardness, and excellent machinability and thermal stability, and is particularly suitable for use as a diamond saw blade substrate. The manufacturing method of the present disclosure includes the steps of smelting, casting, heating, rolling, and off-line heat treatment. The manufacturing method further improves the mechanical properties of the steel for the saw blade by optimally designing the manufacturing process of the steel for the saw blade.

Description

Steel for ultrahigh-hardness saw blade and manufacturing method thereof

Technical Field

The present disclosure relates to steel for saw blades, and more particularly, to steel for ultra-high hardness saw blades having a Rockwell hardness of 50 to 60HRC and a method of manufacturing the same.

Background

The diamond saw blade cuts stone material by rotating at a high speed. The diamond saw blade is used for cutting stone materials such as granite, marble and the like. Generally, the diamond saw blade cuts granite at a linear speed of 25 to 40m/s and cuts marble at a linear speed of 45 to 60m/s. When the natural frequency of the diamond saw blade coincides with the vibration frequency during cutting, a resonance phenomenon may occur. In addition, due to the unevenness of the saw blade or poor installation of the saw blade, lateral pressure is generated during cutting to repeatedly bend the saw blade, resulting in reduced rigidity of the saw blade or fatigue damage. In addition, during the cutting process, the saw blade is subjected to centrifugal force generated by high-speed rotation, and the water tank part is subjected to cyclic cutting pressure and impact force. Therefore, the saw blade should also have a certain toughness.

In view of the above performance requirements for saw blades, saw blades must be subjected to a tempering heat treatment to achieve the desired properties described above. However, the tempering heat treatment is to quench the saw blade in oil and then temper the saw blade for 12 to 14 hours. The quenching and tempering heat treatment process has obvious technical defects, and has the advantages of complex process, long period, high energy consumption and environmental pollution caused by oil quenching.

Therefore, there is a need to obtain a steel for saw blades having ultra-high hardness and good toughness and an environmentally friendly manufacturing method of the steel for saw blades.

Disclosure of Invention

In view of the above, the present inventors have obtained a steel for saw blade, which has excellent mechanical properties (e.g., ultra-high hardness, good toughness), machinability and thermal stability, suitable for manufacturing a large stone saw blade, through reasonable chemical composition design.

In a first aspect, the present disclosure provides a steel for saw blade comprising, in addition to Fe and unavoidable impurities of 90% or more, the following chemical elements in mass percent: c:0.76-0.90%, si:0.10-0.60%, mn:0.20-0.80%, cr:0.20-1.00%, V:0.05-0.50%, al:0.010-0.050%, ti:0.005-0.080%, ca:0.0010 to 0.0040% and is selected from Mo:0.10-0.50%, ni:0.50-1.50%, cu:0.20-0.60% and RE: 0.01-0.08%.

In a second aspect, the present disclosure provides a steel for saw blades comprising, in mass percent, the following chemical elements: c:0.76-0.90%, si:0.10-0.60%, mn:0.20-0.80%, cr:0.20-1.00%, V:0.05-0.50%, al:0.010-0.050%, ti:0.005-0.080%, ca:0.0010 to 0.0040% and is selected from Mo:0.10-0.50%, ni:0.50-1.50%, cu:0.20-0.60% and RE:0.01-0.08%, and the balance of Fe and unavoidable impurities.

In one embodiment, in the steel for saw blade of the present disclosure, the impurity elements satisfy the following in mass percent: p:0.030% or less, preferably 0.020% or less, more preferably 0.015% or less; and/or S: less than 0.010%, preferably less than 0.005%, more preferably less than 0.003%.

In a preferred embodiment, the steel for saw blades of the present disclosure has a C content of 0.76 to 0.88%, preferably 0.76 to 0.86%; si content is 0.20-0.60%, preferably 0.20-0.50%; mn content is 0.20-0.70%, preferably 0.20-0.60%; the Cr content is 0.20-0.80%, preferably 0.30-0.80%; the content of V is 0.10-0.50%; the Al content is 0.015-0.050%, preferably 0.010-0.030%; the Ti content is 0.005-0.080, preferably 0.010-0.060; and/or Ca content of 0.0010 to 0.0035%, preferably 0.0010 to 0.0030%.

In a preferred embodiment, the steel for saw blades of the present disclosure comprises Mo:0.15-0.45%, ni:0.50-1.20%, cu:0.20-0.50% and RE:0.01-0.06% of one or more kinds of materials.

In a more preferred embodiment, the steel for saw blade of the present disclosure comprises Mo:0.15-0.40%, ni:0.50-1.00%, cu:0.20-0.45% and RE:0.01-0.04% of one or more of the following components.

Preferably, the steel for saw blades of the present disclosure has excellent toughness matching, achieving a Rockwell hardness of 50-60HRC and a room temperature impact toughness kv2 of 30-60J, and is particularly suitable for use as a diamond saw blade matrix.

In a third aspect, the present disclosure provides a saw blade made of the steel for saw blade described above.

In a preferred embodiment, the saw blade of the present disclosure is a diamond saw blade.

In a fourth aspect, the present disclosure provides a method of manufacturing the steel for saw blade described above, comprising the steps of: (1) smelting; (2) casting; (3) heating; (4) rolling; (5) off-line heat treatment.

Preferably, in the heating step (3), the heating temperature is 1000-1200 ℃ and the holding time is 1-3 hours.

Preferably, in the rolling step (4), the rough rolling temperature is 900 to 1150 ℃ and the finish rolling temperature is 780 to 880 ℃.

Preferably, in the off-line heat treatment step of (5), the quenching temperature is (Ac 3 +10) DEG C to (Ac 3 +50) DEG C, the cooling stop temperature is 200-400 ℃, and then the cooling is carried out to room temperature.

In a preferred embodiment, in the off-line heat treatment step (5), the quenching is performed by an aerosol cooling method with a cooling rate of 5-30deg.C/s and a tempering temperature of 400-600deg.C.

In a preferred embodiment, in the heating step (3), the heating temperature is 1000 to 1150 ℃.

In a preferred embodiment, in the rolling step (4), the rough rolling temperature is 900-1100 ℃, and the rolling reduction in the rough rolling stage is more than 20%; and/or the finish rolling temperature is 780-860 ℃, and the rolling reduction rate in the finish rolling stage is more than 40%.

In the manufacturing method, the manufacturing process (particularly rolling and off-line heat treatment) of the steel for the saw blade is optimally designed, so that the toughness of the steel for the saw blade is further improved, the microstructure of the steel for the saw blade is thinned, the hardenability of a steel plate is reduced, and the cracking of the steel plate is avoided. The manufacturing method adopts a water-air cooling mode for weak cooling in the quenching heat treatment process, avoids an oil quenching process, and is environment-friendly.

Detailed Description

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

As used herein, the term "and/or" relates to and encompasses any and all possible combinations of more than one of the listed items.

Herein, "rockwell Hardness (HRC)" is used as an index of the hardness value of steel. Rockwell Hardness (HRC) was determined as follows: and according to GB/T230.1-2018 standard, performing hardness test on the surface position of the steel sample by adopting an SCL239 Rockwell hardness tester at room temperature to obtain the corresponding Rockwell hardness.

Rare earth elements are well known in the art and include: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), yttrium (Y), and scandium (Sc).

In the steel for saw blade of the present disclosure, the design principle of each chemical element is specifically as follows:

c (carbon): carbon is the most basic and important element in saw blade steel, and can improve the strength and hardness of the steel, so that the wear resistance of the steel is improved, but the toughness and welding performance of the steel are not good. Thus, in the steel for saw blades of the present disclosure, the carbon content is controlled to be 0.76 to 0.90wt.%, preferably 0.76 to 0.88wt.%, more preferably 0.76 to 0.86wt.%.

Si (silicon): silicon can be solid-dissolved in ferrite and austenite to improve their hardness and strength. However, too high a silicon content may lead to a drastic decrease in toughness of the steel. In addition, because silicon has stronger affinity with oxygen than iron, silicate with low melting point is easy to generate during welding, so that the fluidity of slag and molten metal is increased, and the quality of welding seams is affected. Therefore, the silicon content is not easily excessive. Thus, in the steel for saw blades of the present disclosure, the silicon content is controlled to be 0.10 to 0.60wt.%, preferably 0.20 to 0.60wt.%, more preferably 0.20 to 0.50wt.%.

Mn (manganese): manganese can significantly increase the hardenability of steel, reducing the transformation temperature and critical cooling rate of steel. However, when the manganese content is too high, coarsening of crystal grains is caused, tempering embrittlement sensitivity of steel is increased, and segregation and cracks are easily caused in a cast slab, degrading performance of a steel sheet. Thus, in the steel for saw blades of the present disclosure, the manganese content is controlled to be 0.20 to 0.80wt.%, preferably 0.20 to 0.70wt.%, more preferably 0.20 to 0.60wt.%.

Cr (chromium): chromium can reduce critical cooling rate and improve hardenability of steel. Chromium can be formed in steel (Fe, cr) ₃ C、(Fe，Cr) ₇ C ₃ And (Fe, cr) ₂₃ C ₇ And various carbides, so that the strength and the hardness are improved. In addition, the chromium can prevent or slow down the precipitation and aggregation of carbide during tempering, and can improve the tempering stability of steel. Thus, in the steel for saw blades of the present disclosure, the chromium content is controlled to be 0.20 to 1.00wt.%, preferably 0.20 to 0.80wt.%, more preferably 0.30 to 0.80wt.%.

V (vanadium): vanadium is added mainly to refine grains, and austenite grains in the steel billet are prevented from growing too coarse in the heating stage. In the subsequent multi-pass rolling process, the grains of the steel can be further refined, and the strength and toughness of the steel are improved. Thus, in the steel for saw blades of the present disclosure, the vanadium content is controlled to be 0.05 to 0.50wt.%, preferably 0.10 to 0.50wt.%.

Al (aluminum): aluminum can form tiny indissolvable AlN particles with nitrogen in steel, and fine grains of the steel are formed. Aluminum can refine the grains of the steel, fix nitrogen and oxygen in the steel, lighten the sensitivity of the steel to gaps, reduce or eliminate the aging phenomenon of the steel, and improve the toughness of the steel. Thus, in the steel for saw blades of the present disclosure, the aluminum content is controlled to be 0.010 to 0.050wt.%, preferably 0.015 to 0.050wt.%, more preferably 0.010 to 0.030wt.%.

Ti (titanium): titanium is one of the strong carbide forming elements and can form fine TiC particles with carbon. Fine TiC particles are distributed in the grain boundary, and the effect of refining grains can be achieved. Also, harder TiC particles may improve the wear resistance of the steel. Thus, in the steel for saw blades of the present disclosure, the titanium content is controlled to be 0.005 to 0.080wt.%, preferably 0.005 to 0.025wt.%, more preferably 0.010 to 0.025wt.%.

Ca (calcium): calcium has a remarkable effect on the deterioration of inclusions in steel. The strip sulfide inclusion in the cast steel can be converted into spherical CaS or (Ca, mn) S inclusion by adding a proper amount of calcium into the cast steel. The oxide and sulfide inclusion density formed by the calcium is small, and the floating and the removal are easy. Calcium can also significantly reduce the segregation of sulfur at grain boundaries. Therefore, the addition of a proper amount of calcium is beneficial to improving the quality of cast steel, and further improving the performance of the steel. Thus, in the steel for saw blades of the present disclosure, the calcium content is controlled to 0.0010 to 0.0040wt.%, preferably 0.0010 to 0.0035wt.%, more preferably 0.0010 to 0.0030wt.%.

Mo (molybdenum): the molybdenum can refine grains and improve strength and toughness. Molybdenum is present in the steel in both the solid solution phase and the carbide phase. Therefore, molybdenum has the functions of solid solution strengthening and carbide dispersion strengthening. Molybdenum is an element that reduces temper brittleness, and can improve temper stability. Thus, in the steel for saw blade of the present disclosure, when molybdenum is added, the molybdenum content is controlled to 0.10 to 0.50wt.%, preferably 0.15 to 0.45wt.%, more preferably 0.15 to 0.40wt.%.

Ni (nickel): the nickel and iron may be miscible in any ratio. Nickel can improve the low temperature toughness of steel by refining ferrite grains and has the effect of significantly reducing the cold embrittlement transition temperature. However, an excessively high nickel content easily causes the surface scale of the steel sheet to be difficult to fall off, and the cost is remarkably increased. Thus, in the steel for saw blades of the present disclosure, when nickel is added, the nickel content is controlled to 0.50 to 1.50 wt.%, preferably 0.50 to 1.20wt.%, more preferably 0.50 to 1.00wt.%.

Cu (copper): cu exists mainly in a solid solution state and a simple substance phase precipitation state in steel. Solid-solution Cu can play a solid-solution strengthening role. Because the solid solubility of Cu in ferrite is reduced rapidly along with the temperature reduction, the supersaturated solid-solution Cu can be precipitated and separated out in a simple substance form at a lower temperature, and the precipitation strengthening effect is achieved. Meanwhile, the addition of Cu to steel can significantly improve the atmospheric corrosion resistance of the steel, and particularly, the effect is significant when the Cu is coexistent with P. Thus, in the steel for saw blade of the present disclosure, when Cu is added, the Cu content is controlled to 0.20 to 0.60wt.%, preferably 0.20 to 0.50wt.%. More preferably 0.20-0.45wt.%.

RE (rare earth element): the rare earth elements are added into the steel, so that the segregation of elements such as sulfur, phosphorus and the like can be reduced, the shape, the size and the distribution of nonmetallic inclusions can be improved, meanwhile, grains can be refined, and the hardness can be improved. In addition, the rare earth element can improve the yield ratio, and is beneficial to improving the toughness of the low-alloy high-strength steel. However, the content of rare earth elements is not easy to be excessive, otherwise serious segregation can be generated, and the quality and mechanical property of the casting blank are reduced. Thus, in the steel for saw blade of the present disclosure, when RE is added, the RE content is 0.01 to 0.08wt.%, preferably 0.01 to 0.06wt.%, more preferably 0.01 to 0.04wt.%.

P (phosphorus), S (sulfur): in the steel for saw blade of the present disclosure, both sulfur and phosphorus are harmful elements. Therefore, the lower the sulfur and phosphorus content, the better. In the steel for saw blade of the present disclosure, the phosphorus content is controlled to be 0.030wt.%; the sulfur content is controlled to be less than or equal to 0.010wt.%.

The steel for the saw blade and the manufacturing method thereof have the following advantages:

(1) The steel for the saw blade has simple and reasonable component design, and mainly takes high carbon, low manganese, chromium and vanadium as main additive elements.

(2) The alloy component design of the steel for the saw blade mainly uses low alloy, fully utilizes the characteristics of refinement, reinforcement and the like of micro-alloy elements such as Al, ti and the like, and ensures that the steel for the saw blade has good mechanical properties and the like while adding a proper amount of alloy elements such as Cr, V and the like.

(3) In the manufacturing method, the manufacturing process of the steel for the saw blade is optimally designed, and the mechanical property of the steel for the saw blade is further improved.

(4) In the manufacturing method, controlled rolling is adopted in the rolling process, and the austenitic state and the structure state of a phase transformation product are controlled by controlling the rolling temperature and the rolling reduction, so that the microstructure of the steel for the saw blade is refined.

(5) In the manufacturing method, an off-line heat treatment process is adopted, and the process parameters such as quenching temperature, cooling speed, cooling stopping temperature and the like in the process are controlled to improve the structure refinement and strengthening effects, so that the hardenability and red hardness of steel for the saw blade are improved, and the toughness of the saw blade is also improved.

(6) In the manufacturing method, the quenching adopts a special water-air cooling mode for weak cooling, so that the cost is saved, and the pollution of an oil quenching process to the environment is avoided. In addition, the defect that the steel plate is easy to crack and deform caused by common water quenching is avoided by adopting aerosol cooling. Therefore, the manufacturing method of the present disclosure also has the advantages of low cost, avoidance of environmental pollution, and the like.

The technical scheme of the present disclosure is described in further detail below with reference to examples. It should be understood that the following examples are only illustrative of specific embodiments of the present disclosure and are not intended to limit the scope of the present disclosure in any way.

Examples

Examples 1 to 5 and comparative examples 1 to 4

The steel sheets of examples 1-5 were prepared by the following steps:

according to the formula shown in the following table 1, the mass percentages of chemical elements of the steel plates in each example are controlled, and the corresponding smelting raw materials are sequentially processed according to the following steps: smelting, casting, heating, rolling and off-line heat treatment. Wherein, in the heating step, the heating temperature of the plate blank is 1000-1200 ℃ and the heat preservation time is 1-3 hours; in the rolling step, the rough rolling temperature is 900-1150 ℃ and the finish rolling temperature is 780-880 ℃; in the off-line heat treatment step, the quenching temperature is (Ac 3 +10) DEG C to (Ac 3 +50) DEG C, the cooling stopping temperature is 200-400 ℃, and then the cooling is carried out to room temperature, wherein the quenching adopts an aerosol cooling mode for weak cooling, the cooling speed is 5-30 ℃/s, and the tempering temperature is 400-600 ℃.

Comparative examples 1-4 were prepared in substantially the same manner as described above, except that there were parameters in the chemical composition design and/or process parameters that did not meet the design specifications of the present disclosure.

The compositions and specific process parameters of the steel sheets of examples 1 to 5 and comparative examples 1 to 4 are shown in tables 1 and 2, respectively.

The finally produced saw blades of examples 1 to 5 and comparative examples 1 to 4 were sampled with steels, respectively, and the mechanical properties of each steel sample were tested. The test results are shown in Table 3.

The test method is as follows:

rockwell hardness: and according to GB/T230.1-2018 standard, performing hardness test on the surface position of the steel sample by adopting an SCL239 Rockwell hardness tester at room temperature to obtain the corresponding Rockwell hardness.

Room temperature impact toughness kv2 (J): according to national standard GB/T229-2020, charpy pendulum impact test method for metallic materials, impact toughness detection is carried out on a steel sample at room temperature, and room temperature impact toughness kv2 is obtained.

Table 3 shows the mechanical properties of the steels for saw blades of examples 1 to 5 and comparative examples 1 to 4.

TABLE 3 mechanical Properties of steels for saw blade of examples 1-5 and comparative examples 1-4

Numbering device	Rockwell hardness HRC	Room temperature impact toughness kv2 (J)
			Example 1	53.2	51
Example 2	55.7	45
			Example 3	53.3	49
Example 4	58.2	38
			Example 5	55.8	44
Comparative example 1	35.8	65
			Comparative example 2	60.5	7
Comparative example 3	63.2	6
			Comparative example 4	65.1	5

As can be seen from Table 3, examples 1 to 5 are significantly superior to comparative examples 1 to 4 in terms of the combination of hardness and toughness. The steel for the saw blade with excellent mechanical properties is obtained at low cost through reasonable chemical composition design and optimization of a preferable matching process. In addition, the water vapor cooling mode is adopted in the quenching heat treatment process to realize weak cooling, so that the oil quenching process is avoided, and the quenching heat treatment process is environment-friendly.

All publications, patent applications, patents, and other references mentioned in this disclosure are incorporated herein by reference in their entirety.

While the present disclosure has been described with reference to certain preferred embodiments thereof, it will be apparent to one of ordinary skill in the art that the foregoing is a further detailed description of the present disclosure in connection with the specific embodiments and is not intended to limit the practice of the present disclosure to such descriptions. Various changes in form and detail may be made therein by those skilled in the art, including a few simple inferences or alternatives, without departing from the spirit and scope of the present disclosure.

Claims

1. The steel for the saw blade is characterized by comprising more than 90% of Fe and unavoidable impurities, and further comprising the following chemical elements in percentage by mass:

c:0.76-0.90%, si:0.10-0.60%, mn:0.20-0.80%, cr:0.20-1.00%, V:0.05-0.50%, al:0.010-0.050%, ti:0.005-0.080%, ca:0.0010 to 0.0040% and is selected from Mo:0.10-0.50%, ni:0.50-1.50%, cu:0.20-0.60% and RE: 0.01-0.08%.

2. The steel for the saw blade is characterized by comprising the following chemical elements in percentage by mass:

c:0.76-0.90%, si:0.10-0.60%, mn:0.20-0.80%, cr:0.20-1.00%, V:0.05-0.50%, al:0.010-0.050%, ti:0.005-0.080%, ca:0.0010 to 0.0040% and is selected from Mo:0.10-0.50%, ni:0.50-1.50%, cu:0.20-0.60% and RE:0.01-0.08%, and the balance of Fe and unavoidable impurities.

3. The steel for saw blade according to claim 1 or 2, wherein the impurity elements satisfy the following in mass percent: p:0.030% or less, preferably 0.020% or less, more preferably 0.015% or less; and/or S: less than 0.010%, preferably less than 0.005%, more preferably less than 0.003%.

4. A steel for saw blade according to claim 1 or 2, wherein,

the content of C is 0.76-0.88%, preferably 0.76-0.86%;

si content is 0.20-0.60%, preferably 0.20-0.50%;

mn content is 0.20-0.70%, preferably 0.20-0.60%;

the Cr content is 0.20-0.80%, preferably 0.30-0.80%;

the content of V is 0.10-0.50%;

the Al content is 0.015-0.050%, preferably 0.010-0.030%;

the Ti content is 0.005-0.025%, preferably 0.010-0.025%; and/or

The Ca content is 0.0010 to 0.0035%, preferably 0.0010 to 0.0030%.

5. The steel for saw blade according to claim 1 or 2, characterized in that the steel for saw blade comprises Mo:0.15-0.45%, ni:0.50-1.20%, cu:0.20-0.50% and RE:0.01-0.06% of one or more kinds of materials.

6. The steel for saw blade according to claim 1 or 2, characterized in that the steel for saw blade comprises Mo:0.15-0.40%, ni:0.50-1.00%, cu:0.20-0.45% and RE:0.01-0.04% of one or more of the following components.

7. The steel for saw blade according to any one of claims 1 to 6, wherein the steel for saw blade has a rockwell hardness of 50 to 60HRC and a room temperature impact toughness kv2 of 30 to 60J.

8. A method of manufacturing steel for saw blade as defined in any one of claims 1 to 7, wherein the method comprises the steps of:

(1) Smelting;

(2) Casting;

(3) Heating;

(4) Rolling;

(5) Performing off-line heat treatment;

preferably, in the heating step (3), the heating temperature is 1000-1200 ℃ and the heat preservation time is 1-3 hours;

preferably, in the rolling step (4), the rough rolling temperature is 900-1150 ℃ and the finish rolling temperature is 780-880 ℃;

9. The method according to claim 8, wherein in the off-line heat treatment step (5), the quenching is performed by an aerosol cooling method, the cooling rate is 5 to 30 ℃/s, and the tempering temperature is 400 to 600 ℃.

10. The method according to claim 8, wherein in the heating step (3), the heating temperature is 1000 to 1150 ℃.

11. The manufacturing method according to any one of claims 8 to 10, wherein in the (4) rolling step, the rough rolling temperature is 900 to 1100 ℃, and the rolling reduction in the rough rolling stage is more than 20%; and/or the finish rolling temperature is 780-860 ℃, and the rolling reduction rate in the finish rolling stage is more than 40%.

12. A saw blade made of the saw blade steel of any one of claims 1 to 7.