Crawler steel for light excavator and preparation process thereof

Abstract

The invention discloses track steel for a light excavator and a preparation process of the track steel, and belongs to the technical field of track steel, and the track steel comprises the following components in percentage by weight: 0.20 to 0.34 percent of C, 2.11 to 3.05 percent of Si, 3.06 to 4.08 percent of Mn, 2.04 to 3.06 percent of Al, 1.00 to 1.35 percent of Co, 1.00 to 1.30 percent of Cu, 0.30 to 0.56 percent of Ti, 0.01 to 0.02 percent of V, 0.005 to 0.006 percent of Nb, 0.005 to 0.006 percent of Bi and the balance of Fe and inevitable impurities. Through the mode, the track steel has the advantages of light weight, high strength, high impact resistance, good corrosion resistance and the like, can be well used in the technical field of track steel for light excavators, enhances the strength, impact resistance and corrosion resistance of the surface of a track, can avoid pits and cracks, reduces the corrosion speed, and prolongs the service life of the track.

Description

Technical Field

[0001] The invention relates to the technical field of crawler steel, and in particular to crawler steel for a light excavator and a preparation process thereof. Background Art

[0002] Light excavator is a kind of earthwork construction machinery with small size, light weight and low fuel consumption. It is widely used in urban construction and small and medium-sized projects, such as road maintenance, landscaping, farmland transformation and other fields.

[0003] As an important component of the excavator, the crawler track not only needs to have high strength, but also needs to be relatively lightweight in order to reduce the overall weight of the excavator.

[0004] Chinese invention patent CN113061807B discloses a 780MPa grade lightweight high-strength steel and a preparation method thereof, wherein the steel contains C: 0.15% to 0.25%, Si: 0.8% to 1.5%, Mn: 1.0% to 2.0%, P: 0.03% to 0.05%, S≤0.03%, Al: 3.0% to 5.0%, Ti: 0.03% to 0.2%, Nb: 0.03% to 0.2%, Bi: 0.05% to 0.2%, the remainder being Fe and unavoidable impurities, and satisfying 0.8≤(13C+2Mn) / (Al+1.2Si)≤1.2.

[0005] However, during the driving process of the light excavator, the crawler tracks are in direct and frequent contact with the ground, ore, mud, sand, sewage and other materials, and even collide with them, so that the contact surface will be subjected to greater and more frequent wear and impact, causing pits or even cracks on the crawler surface, affecting the service life of the crawler tracks; at the same time, sewage and other materials will also corrode the surface of the crawler tracks, further aggravating the defects of the crawler surface.

[0006] Based on this, the present invention designs a crawler steel for a light excavator and a preparation process thereof to solve the above problems. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, the present invention provides a crawler steel for a light excavator and a preparation process thereof.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] A crawler steel for a light excavator comprises the following components in weight percentage: C: 0.20-0.34%, Si: 2.11-3.05%, Mn: 3.06-4.08%, Al: 2.04-3.06%, Co: 1.00-1.35%, Cu: 1.00-1.30%, Ti: 0.30-0.56%, V: 0.01-0.02%, Nb: 0.005-0.006%, Bi: 0.005-0.006%, and the rest are Fe and inevitable impurities.

[0010] Furthermore, the mass ratio of C:Mn:Al:Co:Cu:Ti is 0.2:4:3:1:1:0.3.

[0011] Furthermore, wherein 1<(5C+Mn) / (Cu+Ti+Al)<1.2.

[0012] Furthermore, V+Nb+Bi<C.

[0013] A preparation process of crawler steel for light excavator comprises the following steps:

[0014] Melting: The raw materials are melted, and an inert gas is blown into the molten steel. The inert gas includes nitrogen and argon. The blowing starts with argon and ends with nitrogen. The ratio of the blowing time of nitrogen to the blowing time of argon is 1:1. The flow rate of nitrogen is equal to the flow rate of argon, and an ingot is prepared;

[0015] Hot forging: The ingot is kept at 1150-1170℃ for 1.3-1.5h and then forged into steel slab;

[0016] Heat treatment: homogenize the steel slab at 1100-1130℃ for 0.8-1.2h;

[0017] Hot rolling: hot rolling the steel slab at 1000-1100℃ and water quenching;

[0018] Cold rolling: cold rolling the steel slab;

[0019] Continuous annealing: The steel slab is continuously annealed at a temperature of 610-650°C, an annealing holding time of 20-30 min, a cooling rate of 25-40°C / s, an annealing time of 2-3 h, and a cooling method of water cooling;

[0020] Solution aging treatment: The steel slab is solution aging treated at 980-1020°C for 3-4 min, then solution aging treated at 200-300°C for 0.5-1 h, and water quenched.

[0021] Furthermore, continuous annealing: the steel slab is continuously annealed, the annealing temperature is 640°C, the annealing holding time is 25min, the cooling rate is 30°C / s, the annealing time is 2.5h, and the cooling method is water cooling.

[0022] Furthermore, solution aging treatment: the steel slab is solution aging treated at 1010°C for 3 min, then solution aging treated at 288°C for 0.8 h, and water quenched.

[0023] Furthermore, hot forging: the ingot is kept at 1160℃ for 1.4h and then forged into steel slab.

[0024] Furthermore, the track steel properties are:

[0025] Yield strength 892~927MPa, tensile strength 742~904MPa, elongation 27.2~31.0%, strength-ductility product 22428~25566.4MPa·%, -20℃ Charpy U-type longitudinal impact energy 62~71J; corrosion rate: 4.07~4.31μm / a.

[0026] In order to better achieve the purpose of the present invention, the present invention also provides a crawler steel for a light excavator and a preparation process thereof.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: the track steel of the present invention has the advantages of light weight, high strength, high impact resistance, good corrosion resistance, etc., and can be well used in the technical field of track steel for light excavators, enhancing the strength, impact resistance and corrosion resistance of the track surface, avoiding the formation of pits and cracks, reducing the corrosion rate, and increasing the service life of the track. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1: In some embodiments, a crawler steel for a light excavator comprises the following components in weight percentage: C: 0.20%, Si: 2.11%, Mn: 3.06%, Al: 2.04%, Co: 1.00%, Cu: 1.00%, Ti: 0.30%, V: 0.01%, Nb: 0.005%, Bi: 0.005%, and the rest are Fe and inevitable impurities.

[0030] The preparation process of crawler steel for light excavator includes the following steps:

[0031] Melting: The raw materials are melted, and an inert gas is blown into the molten steel. The inert gas includes nitrogen and argon. The blowing starts with argon and ends with nitrogen. The ratio of the blowing time of nitrogen to the blowing time of argon is 1:1. The flow rate of nitrogen is equal to the flow rate of argon, and an ingot is prepared;

[0032] Hot forging: The ingot is kept at 1150℃ for 1.3h and then forged into steel slab;

[0033] Heat treatment: The steel slab was homogenized and heat treated at 1100℃ for 0.8h;

[0034] Hot rolling: hot rolling the steel slab at 1000℃ and water quenching;

[0035] Cold rolling: cold rolling the steel slab;

[0036] Continuous annealing: The steel slab is continuously annealed at an annealing temperature of 610°C, an annealing holding time of 20 min, a cooling rate of 25°C / s, an annealing time of 2 h, and a cooling method of water cooling;

[0037] Solution aging treatment: The steel slab was solution aged at 980°C for 3 min, then solution aged at 200°C for 0.5 h, and water quenched.

[0038] The performance test results of track steel (thickness 2mm) are as follows: yield strength 913MPa, tensile strength 801MPa, elongation 28.0%, strength-ductility product 22428MPa·%, -20℃ Charpy U-type longitudinal impact energy 65J;

[0039] Corrosion performance test: GAMRY potentiostat was used to analyze the potentiodynamic polarization and electrochemical impedance spectroscopy in NaCl solution. 2 The steel plate sample was immersed in NaCl solution for 0.5h to stabilize its open circuit potential, and the corrosion rate was calculated to be 4.28μm / a.

[0040] Example 2: In some embodiments, a crawler steel for a light excavator includes the following components in weight percentage: C: 0.34%, Si: 3.05%, Mn: 4.08%, Al: 3.06%, Co: 1.35%, Cu: 1.30%, Ti: 0.56%, V: 0.02%, Nb: 0.006%, Bi: 0.006%, and the rest are Fe and inevitable impurities.

[0041] The preparation process of crawler steel for light excavator includes the following steps:

[0042] Melting: The raw materials are melted, and an inert gas is blown into the molten steel. The inert gas includes nitrogen and argon. The blowing starts with argon and ends with nitrogen. The ratio of the blowing time of nitrogen to the blowing time of argon is 1:1. The flow rate of nitrogen is equal to the flow rate of argon, and an ingot is prepared;

[0043] Hot forging: The ingot is kept at 1170℃ for 1.5h and then forged into steel slab;

[0044] Heat treatment: The steel slab was homogenized and heat treated at 1130℃ for 1.2h;

[0045] Hot rolling: hot rolling the steel slab at 1100℃ and water quenching;

[0046] Cold rolling: cold rolling the steel slab;

[0047] Continuous annealing: The steel slab is continuously annealed at an annealing temperature of 650°C, an annealing holding time of 30 min, a cooling rate of 40°C / s, an annealing time of 3 h, and a cooling method of water cooling;

[0048] Solution aging treatment: The steel slab was solution aged at 1020°C for 4 min, then solution aged at 300°C for 1 h, and water quenched.

[0049] The performance test results of track steel (thickness 2mm) are as follows: yield strength 905MPa, tensile strength 742MPa, elongation 31.0%, strength-ductility product 23002MPa·%, -20℃ Charpy U-type longitudinal impact energy 62J;

[0050] Corrosion performance test: GAMRY potentiostat was used to analyze the potentiodynamic polarization and electrochemical impedance spectroscopy in NaCl solution. 2 The steel plate sample was immersed in NaCl solution for 0.5h to stabilize its open circuit potential, and the corrosion rate was calculated to be 4.16μm / a.

[0051] Example 3: In some embodiments, a crawler steel for a light excavator includes the following components in weight percentage: C: 0.32%, Si: 2.65%, Mn: 3.15%, Al: 2.23%, Co: 1.27%, Cu: 1.10%, Ti: 0.35%, V: 0.011%, Nb: 0.0055%, Bi: 0.0052%, and the rest are Fe and unavoidable impurities.

[0052] The preparation process of crawler steel for light excavator includes the following steps:

[0053] Melting: The raw materials are melted, and an inert gas is blown into the molten steel. The inert gas includes nitrogen and argon. The blowing starts with argon and ends with nitrogen. The ratio of the blowing time of nitrogen to the blowing time of argon is 1:1. The flow rate of nitrogen is equal to the flow rate of argon, and an ingot is prepared;

[0054] Hot forging: The ingot is kept at 1160℃ for 1.4h and then forged into steel slab.

[0055] Heat treatment: The steel slab was homogenized and heat treated at 1120℃ for 1h;

[0056] Hot rolling: hot rolling the steel slab at 1050℃ and water quenching;

[0057] Cold rolling: cold rolling the steel slab;

[0058] Continuous annealing: The steel slab is continuously annealed at an annealing temperature of 640°C, an annealing holding time of 25 min, a cooling rate of 30°C / s, an annealing time of 2.5 h, and a cooling method of water cooling.

[0059] Solution aging treatment: The steel slab was solution aged at 1010°C for 3 min, then solution aged at 288°C for 0.8 h, and water quenched.

[0060] The performance test results of track steel (thickness 2mm) are as follows: yield strength 927MPa, tensile strength 841MPa, elongation 30.4%, strength-ductility product 25566.4MPa·%, -20℃ Charpy U-type longitudinal impact energy 71J;

[0061] Corrosion performance test: GAMRY potentiostat was used to analyze the potentiodynamic polarization and electrochemical impedance spectroscopy in NaCl solution. 2 The steel plate sample was immersed in NaCl solution for 0.5h to stabilize its open circuit potential, and the corrosion rate was calculated to be 4.31μm / a.

[0062] Example 4: In some embodiments, a crawler steel for a light excavator includes the following components in weight percentage: C: 0.20%, Si: 2.95%, Mn: 4.00%, Al: 3.00%, Co: 1.00%, Cu: 1.00%, Ti: 0.30%, V: 0.01%, Nb: 0.005%, Bi: 0.006%, and the rest are Fe and inevitable impurities.

[0063] The preparation process of crawler steel for light excavator includes the following steps:

[0064] Melting: The raw materials are melted, and an inert gas is blown into the molten steel. The inert gas includes nitrogen and argon. The blowing starts with argon and ends with nitrogen. The ratio of the blowing time of nitrogen to the blowing time of argon is 1:1. The flow rate of nitrogen is equal to the flow rate of argon, and an ingot is prepared;

[0065] Hot forging: The ingot is kept at 1155℃ for 1.5h and then forged into steel slab;

[0066] Heat treatment: The steel slab was homogenized and heat treated at 1110°C for 0.9h;

[0067] Hot rolling: hot rolling the steel slab at 1020℃ and water quenching;

[0068] Cold rolling: cold rolling the steel slab;

[0069] Continuous annealing: The steel slab is continuously annealed at an annealing temperature of 640°C, an annealing holding time of 23 min, a cooling rate of 29°C / s, an annealing time of 2.5 h, and a cooling method of water cooling;

[0070] Solution aging treatment: The steel slab was solution aged at 1010°C for 3.5 min, then solution aged at 220°C for 0.6 h, and water quenched.

[0071] The performance test results of the track steel (thickness is 2mm): yield strength 892MPa, tensile strength 904MPa, elongation 27.2%, strength-ductility product 24588.8MPa·%, and -20℃ Charpy U-type longitudinal impact energy 63J.

[0072] Corrosion performance test: GAMRY potentiostat was used to analyze the potentiodynamic polarization and electrochemical impedance spectroscopy in NaCl solution. 2 The steel plate sample was immersed in NaCl solution for 0.5h to stabilize its open circuit potential, and the corrosion rate was calculated to be 4.07μm / a.

[0073] The track steel of the present invention has the advantages of light weight, high strength, high impact resistance, good corrosion resistance, etc. It can be well used in the technical field of track steel for light excavators, enhances the strength, impact resistance and corrosion resistance of the track surface, avoids the formation of pits and cracks, reduces the corrosion rate, and increases the service life of the track.

[0074] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those 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 will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A crawler steel for a light excavator, characterized in that: The invention comprises the following components in weight percentage: C: 0.20-0.34%, Si: 2.11-3.05%, Mn: 3.06-4.08%, Al: 2.04-3.06%, Co: 1.00-1.35%, Cu: 1.00-1.30%, Ti: 0.30-0.56%, V: 0.01-0.02%, Nb: 0.005-0.006%, Bi: 0.005-0.006%, and the rest are Fe and inevitable impurities.

2. The crawler steel for a light excavator according to claim 1, characterized in that: in, The mass ratio of C:Mn:Al:Co:Cu:Ti is 0.2:4:3:1:1:0.

3.

3. The crawler steel for a light excavator according to claim 2, characterized in that: in, 1<(5C+Mn) / (Cu+Ti+Al)<1.

2.

4. The crawler steel for a light excavator according to claim 3, characterized in that: V+Nb+Bi<C.

5. A process for preparing crawler steel for light excavator according to claim 4, characterized in that: The following steps are involved: Melting: The raw materials are melted, and an inert gas is blown into the molten steel. The inert gas includes nitrogen and argon. The blowing starts with argon and ends with nitrogen. The ratio of the blowing time of nitrogen to the blowing time of argon is 1:

1. The flow rate of nitrogen is equal to the flow rate of argon, and an ingot is prepared; Hot forging: The ingot is kept at 1150-1170℃ for 1.3-1.5h and then forged into steel slab; Heat treatment: homogenize the steel slab at 1100-1130℃ for 0.8-1.2h; Hot rolling: hot rolling the steel slab at 1000-1100℃ and water quenching; Cold rolling: cold rolling the steel slab; Continuous annealing: The steel slab is continuously annealed at a temperature of 610-650°C, an annealing holding time of 20-30 min, a cooling rate of 25-40°C / s, an annealing time of 2-3 h, and a cooling method of water cooling; Solution aging treatment: The steel slab is solution aging treated at 980-1020°C for 3-4 min, then solution aging treated at 200-300°C for 0.5-1 h, and water quenched.

6. The process for preparing crawler steel for light excavator according to claim 5, characterized in that: Continuous annealing: The steel slab is continuously annealed at an annealing temperature of 640°C, an annealing holding time of 25 min, a cooling rate of 30°C / s, an annealing time of 2.5 h, and a cooling method of water cooling.

7. The process for preparing crawler steel for light excavator according to claim 6, characterized in that: Solution aging treatment: The steel slab was solution aged at 1010°C for 3 min, then solution aged at 288°C for 0.8 h, and water quenched.

8. The process for preparing crawler steel for light excavator according to claim 7, characterized in that: Hot forging: The ingot is kept at 1160℃ for 1.4h and then forged into steel slab.

9. The process for preparing crawler steel for light excavator according to claim 8, characterized in that: Track steel properties are: Yield strength 892~927MPa, tensile strength 742~904MPa, elongation 27.2~31.0%, strength-ductility product 22428~25566.4MPa·%, -20℃ Charpy U-type longitudinal impact energy 62~71J; corrosion rate: 4.07~4.31μm / a.