As a core harvesting machine in agricultural production, the service life of combine harvesters is directly related to agricultural production efficiency, farmers' input-output ratio, and the quality of agricultural mechanization development. With the rapid popularization of agricultural mechanization, clarifying the service life standards of combine harvesters, mastering the key factors affecting their service life, and doing a good job in daily maintenance and scrapping management are core industry knowledge that every agricultural machinery user, practitioner and relevant management department needs to understand. This article will comprehensively analyze the service life of combine harvesters by combining national industry standards and actual production scenarios.

I. Definition of Industry Standards for the Service Life of Combine Harvesters

China has formulated clear industry standards for the service life of agricultural machinery. The scrapping and service life specifications of combine harvesters mainly follow the "NY/T 1875—2010 Technical Conditions for Prohibition and Scrapping of Combine Harvesters". This standard sets a clear red line for the service life of combine harvesters, and combined with local agricultural machinery subsidy policies and actual use conditions, a unified and practical service life standard has been formed, which is specifically classified as follows:

1. Statutory Service Life by Machine Type

According to industry standards and the implementation rules of local agricultural machinery management departments, there are significant differences in the statutory recommended service life of combine harvesters according to different machine types, which is mainly due to the different structural complexity, operation intensity and wear rate of different machine types:

• Self-propelled combine harvesters: As the most widely used machine type in the market, they have complex structures, integrating multiple systems such as walking, harvesting, threshing and cleaning, and have high operation intensity. According to industry standards, the statutory service life of self-propelled combine harvesters is 12 years. For machines exceeding this service life, if they have not passed professional technical appraisal and meet the safe operation standards, they need to go through scrapping procedures in accordance with regulations.

• Mounted combine harvesters: This type of machine needs to be used in conjunction with tractors, has no independent walking system, has a relatively simple structure, and its wear degree is lower than that of self-propelled machine types. Its statutory service life is 10 years, and it also needs to undergo technical testing after reaching the service life. Those that do not meet the safe operation requirements should be scrapped.

• Crawler-type combine harvesters: They are mainly suitable for complex operating environments such as paddy fields and muddy plots, and the crawler and walking system wear out quickly. Their service life is the same as that of self-propelled combine harvesters, which is 12 years. In some regions, combined with the particularity of the operating environment, the testing standards for crawler-type machine types will be appropriately adjusted.

2. Scrapping Judgment Standards Beyond Service Life

In addition to the statutory service life, combine harvesters, even if they have not reached the service life, need to be compulsorily scrapped or are recommended to be scrapped if the following situations occur. This is also an important basis for measuring their actual service life, which meets the requirements of agricultural production safety and efficiency:

• After repair, their technical performance still fails to meet the relevant standards of the "Safety Technical Requirements for Combine Harvesters", and there are serious safety hazards, such as failure of the braking system, faults in the steering system, and severe wear of the header and threshing system that cannot be repaired.

• The machine is seriously damaged, and the core components (such as engine, gearbox, header drum, etc.) are irreversibly damaged, and there is no repair value, or the repair cost is too high. It is estimated that the major repair cost exceeds 50% of the price of similar new products, so it is not necessary to continue using it from an economic perspective.

• Machine types explicitly eliminated by national or local agricultural competent departments are not suitable for continued use in agricultural production due to backward technology, high energy consumption, and non-compliant emissions, and need to be scrapped in accordance with regulations.

• There is no source of spare parts, and the core components cannot be replaced after being damaged, resulting in the machine being unable to operate normally, and it cannot meet the operation requirements through technical transformation.

II. Core Factors Affecting the Service Life of Combine Harvesters

The statutory service life is a basic reference for the service life of combine harvesters, but in actual use, the service life of the machine will be affected by many factors such as operating environment, usage habits, maintenance level, and machine quality. Some well-maintained machines can exceed the statutory standard by 1-3 years, while poorly maintained machines may need to be scrapped after 5-8 years of use. The specific influencing factors are as follows:

1. Operating Environment and Operation Intensity

The operating environment is a key factor affecting the wear rate of combine harvesters. In plain areas, the plots are flat and the crops are planted regularly. Combine harvesters run smoothly during operation, and the wear of the header, walking system and threshing system is small, so the service life is relatively long. In mountainous and hilly areas, the plots are rugged and the crop row spacing is irregular. The machine needs to frequently adjust the speed and direction, the header is prone to collision damage, the load of the walking system increases, and the wear rate accelerates. In addition, when operating in paddy fields and muddy plots, the crawlers or tires are prone to slipping and getting stuck, which not only increases the engine load, but also aggravates the wear of the walking system and transmission system, shortening the service life of the machine.

Operation intensity also has a significant impact. Machines that are only used during the harvest season (such as wheat and rice harvest seasons) in a year have a short annual operation time and small wear. However, combine harvesters engaged in cross-regional operations can have an annual operation time of hundreds of hours. The core components are in a high-load operation state for a long time, and the wear rate is much higher than that of local operation machines, so the service life will be shortened accordingly.

2. Daily Maintenance and Repair Level

Daily maintenance is a core means to extend the service life of combine harvesters. Standardized maintenance can effectively reduce component wear and prevent failures. Some farmers do not pay enough attention to machine maintenance and fail to clean, lubricate and inspect the machine as required before and after operation, resulting in residual crop straw and soil inside the machine and poor lubrication between components. Long-term accumulation will cause component rust and increased wear, and even cause failure shutdown. The scientific maintenance process includes checking the oil level of engine oil, coolant and hydraulic oil, and cleaning the header and threshing drum before operation; regularly checking the operating status of components and timely cleaning blockages during operation; thoroughly cleaning the machine after operation, lubricating and tightening the wear-prone components, and timely repairing or replacing the damaged components, which can significantly reduce wear and extend the service life of the machine.

The repair level is also crucial. When the machine fails, choosing professional maintenance personnel and regular spare parts can ensure the maintenance quality and avoid secondary damage to components caused by improper maintenance. If the maintenance personnel are unskilled and use inferior spare parts, it will not only fail to solve the failure, but also accelerate the wear of the machine and shorten the service life.

3. Machine Quality and Core Component Performance

The production quality of combine harvesters is the foundation of their service life. Machines produced by regular manufacturers use high-quality steel and core components, have standardized manufacturing processes and reasonable structural design, strong wear resistance and impact resistance, and relatively long service life. Inferior machines produced by small manufacturers have insufficient steel thickness, poor quality of core components, and rough manufacturing processes, which are prone to component breakage and rapid wear. Their actual service life may only be half of that of regular machine types. In addition, the performance of core components such as engines and gearboxes directly determines the overall service life of the machine. High-quality core components have stronger wear resistance and load resistance, which can effectively extend the machine's use cycle.

4. Professional Quality of Operators

The professional quality of combine harvester operators directly affects the use status of the machine. Professional operators are familiar with the structure, performance and operation specifications of the machine, can adjust the operation parameters according to crop varieties and plot conditions, and avoid overloading the machine. During operation, they can detect machine abnormalities in time and take corresponding measures to prevent failures. Operators who lack professional training are prone to illegal operations, such as high-speed driving, forced harvesting of lodged crops, and overloading feeding. These behaviors will damage the header, threshing system, engine and other components, accelerate machine wear and shorten the service life.

III. Practical Methods to Extend the Service Life of Combine Harvesters

Combined with the core factors affecting the service life of combine harvesters, farmers and agricultural machinery practitioners can extend the service life of the machine scientifically, reduce the use cost and improve agricultural production efficiency through the following methods:

1. Standardize Operation to Reduce Operation Wear

Operators need to receive professional training, be familiar with machine operation specifications, and reasonably adjust operation parameters such as operation speed and feeding amount according to crop varieties, maturity and plot conditions. When harvesting lodged crops, the operation speed should be reduced, the header height should be adjusted to avoid the header colliding with the ground; sudden acceleration and sudden braking should be avoided during operation to reduce the impact on the engine and transmission system; when the machine has abnormal noise, vibration and other abnormal conditions, it should be shut down immediately for inspection, and the operation can be continued after the failure is eliminated to avoid the expansion of the failure.

2. Do a Good Job in Daily Maintenance and Establish Maintenance Ledgers

Formulate a sound daily maintenance plan, and strictly do a good job in maintenance before, during and after operation in accordance with the machine's instruction manual. Before operation, focus on checking the oil level of engine oil, coolant, hydraulic oil and fuel, check the tire pressure and crawler tightness, and clean the residual debris on the header, drum and other components; during operation, check the operating status of components every 2-3 hours, clean the blockages of the threshing drum and cleaning screen, and check the tightness of bolts and nuts; after operation, thoroughly clean the machine, focus on cleaning the soil and straw on the header, chassis and engine compartment, lubricate the wear-prone components such as cutter blades, drums and chains, and timely repair or replace the damaged components. At the same time, establish a maintenance ledger to record the maintenance time, content, replaced components and other information for subsequent traceability and management.

3. Store Reasonably and Do a Good Job in Maintenance During Idle Period

The maintenance of combine harvesters during the idle period (non-harvest season) is crucial to extending the service life. Before idling, the machine should be cleaned, the coolant, fuel and hydraulic oil should be drained, and the inside of the engine should be lubricated; adjust the header, drum and other components to the non-operation state to avoid long-term stress on the components; park the machine in a dry, ventilated and rainproof place to avoid direct sunlight and rain soaking to prevent the body from rusting; regularly check the machine status, start the engine to run for 10-15 minutes every month, check the operation of each component, apply anti-rust oil to the rust-prone components, and inflate the tires for maintenance to avoid tire deformation.

4. Choose Regular Maintenance and Use High-Quality Spare Parts

When the machine fails, it should choose regular agricultural machinery maintenance stations and professional maintenance personnel, and avoid disassembling it by yourself or finding unqualified maintenance personnel for maintenance. During maintenance, give priority to using original spare parts or high-quality spare parts that meet national standards, reject inferior spare parts, and ensure the maintenance quality. At the same time, conduct a comprehensive inspection of the machine regularly, detect and repair potential failures in time, avoid the development of small failures into major ones, and reduce the maintenance cost.

5. Choose the Right Machine Type According to Operation Needs

When purchasing combine harvesters, farmers should choose the appropriate machine type according to the local operating environment, crop varieties and operation intensity. In plain areas, wheeled self-propelled combine harvesters can be selected, which have high operation efficiency and small wear; in mountainous and hilly areas, small and light machine types can be selected for flexible operation; in paddy fields, crawler-type combine harvesters should be selected to adapt to muddy plot operations. Choosing the right machine type can avoid "overkill" or "underpowered" of the machine, reduce unnecessary wear and extend the service life.

IV. Scrapping Management and Resource Utilization of Combine Harvesters

When combine harvesters reach the statutory service life or meet the scrapping standards, they need to be scrapped in accordance with regulations. This is not only a requirement to ensure agricultural production safety, but also an important link to realize the recycling of agricultural machinery resources. At present, China has established a sound subsidy policy for the scrapping and renewal of agricultural machinery, encouraging farmers to timely scrap old, high-energy-consuming and high-pollution combine harvesters and replace them with new, efficient and environmentally friendly machine types.

1. Scrapping Handling Process

Farmers need to bring relevant materials such as the driving license, registration certificate of the combine harvester and their own ID cards to the local agricultural and rural department or agricultural machinery supervision agency to apply for scrapping; the relevant department conducts technical appraisal on the machine, and issues a scrapping appraisal certificate after confirming that it meets the scrapping standards; farmers send the machine to the designated agricultural machinery recycling and dismantling enterprise with the scrapping appraisal certificate, and the recycling enterprise dismantles and recycles the machine and issues a recycling certificate; farmers apply for the scrapping and renewal subsidy from the local financial department with the recycling certificate and relevant materials. The subsidy standard is determined according to factors such as machine type and service life, which effectively reduces the cost for farmers to replace new machines.

2. Resource Utilization of Scrapped Machines

Scrapped combine harvesters are not completely discarded. Their core components such as engines, gearboxes and steel can be recycled and reused through professional dismantling to realize resource recycling. Regular agricultural machinery recycling and dismantling enterprises will classify and dismantle scrapped machines, repair and reuse the repairable components, and recycle the metal of the non-repairable components, which not only reduces resource waste, but also reduces environmental pollution. At the same time, the parts of some old machine types can be used as second-hand spare parts for the maintenance of the same type of machines, further improving the resource utilization rate.

V. Impact of Industry Development Trends on the Service Life of Combine Harvesters

With the rapid development of agricultural mechanization and intelligence, the technical level of combine harvesters has been continuously improved. New combine harvesters have been continuously optimized in structural design, core component performance, energy conservation and consumption reduction, and their service life has also shown an extended trend. At the same time, the state has continuously improved the environmental protection and safety standards for agricultural machinery, accelerating the elimination of old machine types and promoting the development of combine harvesters in the direction of high efficiency, durability and environmental protection.

In addition, the popularization of agricultural machinery socialized services has made the use of combine harvesters more professional and standardized. Professional agricultural machinery service organizations have perfect maintenance and repair systems, which can effectively extend the service life of machines and improve the utilization rate of machines. In the future, with the application of intelligent maintenance technology and remote monitoring technology on combine harvesters, real-time monitoring of the machine's operating status can be realized, potential failures can be detected in time, and the service life and operation efficiency of the machine can be further improved.

VI. Summary

The service life of combine harvesters is a comprehensive indicator, which is not only regulated by the statutory service life, but also affected by many factors such as operating environment, usage habits and maintenance level. For farmers, clarifying the service life standards of combine harvesters, mastering scientific operation and maintenance methods, and timely handling scrapping and renewal procedures can not only ensure agricultural production safety and improve operation efficiency, but also reduce the use cost and realize the sustainable development of agricultural production. For the industry, continuously improving the production quality and technical level of combine harvesters and improving the scrapping management and resource recycling system will further promote the high-quality development of agricultural mechanization and provide strong support for China's agricultural modernization construction.