Professional Guide to Purchasing Agricultural Machinery Parts and Quality Identification

Professional Guide to the Selection and Quality Identification of Agricultural Machinery Parts I. Classification and Characteristics of Commonly Used Agricultural Machinery Parts (I) Core Components of the Power System Agricultural Tires — Genuine product characteristics: complete sidewall markings (including ply rating, cord material, production batch number); uniform tread pattern depth (new tires ≥8 mm); good carcass rubber elasticity (rebound rate ≥80%). Inferior performance: markings blurred or missing; sidewall thickness variation >1.5 mm; rubber aging cracks. Threaded Fasteners — Quality standards: surface finish Ra ≤3.2 μm; thread go gauge inspection qualified; tensile strength ≥400 MPa. Testing methods: screw-fit test with standard parts (should be free of jamming); torque test (reaching more than 90% of the nominal value). (II) Key Components of the Transmission System Gear Sets — High-quality characteristics: tooth surface hardness HRC58-62; involute tooth profile accuracy grade 7 or above; carburized layer depth 0.8-1.2 mm. Key inspection points: magnetic particle inspection for cracks; red lead powder meshing test (contact area ≥75%). V-Belts — Genuine product indicators: cord arrangement density ≥60 cords/10 cm; rubber tensile strength ≥15 MPa; service life ≥1000 hours. Inferior characteristics: cross-sectional dimension deviation >1 mm; belt body delamination. (III) Core Engine Components Piston Ring Sets — Quality requirements: end gap 0.3-0.5 mm; light leakage ≤30°; surface chrome plating thickness 0.1-0.15 mm. Testing methods: feeler gauge measurement of ring groove clearance; light transmission inspection for roundness. Filter Systems — Genuine product standards: filtration accuracy 10-20 μm (diesel); initial resistance ≤2.5 kPa; filter paper grammage ≥100 g/m². Counterfeit characteristics: end cap sealing not tight; filter material thickness uneven. II. Three-Dimensional Quality Identification Method (I) Visual Inspection System Surface quality inspection: machining texture should be uniform and continuous; coating quality free of bubbles and peeling; clear markings (including material, specifications, etc.). Tool preparation: digital caliper (accuracy 0.01 mm); thread gauge (go/no-go gauge set). Key dimensions: bearing inner diameter tolerance ±0.005 mm; gear module error ≤0.02. (II) Auditory Inspection Method Tap testing: clear sound for castings is preferable; no dull cracking sound for welded parts. Running test: no abnormal squealing from bearings; uniform gear meshing sound. (III) Tactile Inspection Points Surface texture: precision-machined surface Ra ≤1.6 μm; casting surface free of sharp protrusions. Fit testing: shaft-hole fit H7/g6 grade is preferable; thread fit free of obstruction when screwed in by hand. III. Recommended Professional Testing Tools | Testing Item | Recommended Tool | Accuracy Requirement | | Dimensional measurement | Digital micrometer | 0.001 mm | | Hardness testing | Rockwell hardness tester | ±1 HRC | | Geometric tolerance | Coordinate measuring machine | 0.005 mm | | Material analysis | Spectrometer | 0.01% | IV. Purchasing Pitfall Avoidance Guide Channel selection: prioritize manufacturer-authorized dealers; on e-commerce platforms, look for brand flagship stores. Price warnings: be vigilant if below market price by 30%; require tax payment certificates. Document verification: three essential certificates (product qualification certificate, quality guarantee, test report). After-sales protection: warranty period of no less than 1 year; return and exchange policy within 15 days. V. Recommendations for Parts Usage Break-in period management: new gear sets run under light load for 50 hours; new piston rings control speed for the first 20 hours. Maintenance cycle: lubricate key components every 100 hours; inspect wear amount quarterly. Scrap standards: gear tooth thickness wear >15%; bearing clearance >0.1 mm; belt cracks >3 per 10 cm. Through systematic quality identification methods and standardized procurement processes, the safety and economy of agricultural machinery parts usage can be ensured. It is recommended to establish parts usage records, documenting replacement cycles and performance, to provide data support for future procurement.