QA

Quality Assurance

Strictly control the quality inspection of the whole process of agricultural machinery parts to ensure that each product is accurate and reliable, providing you with zero-defect durability guarantee.

Quality Inspection Process

Incoming Material Inspection

- Material composition testing: Spectrum analyzer (direct reading spectrometer) to verify the chemical composition of steel, cast iron (such as carbon, silicon, manganese content). Mechanical properties testing: tensile testing machine to test tensile strength, yield strength; impact testing machine to detect toughness (for gears, shaft parts).

- Mechanical performance test: tensile testing machine to test the tensile strength, yield strength; impact testing machine to detect toughness (applicable to gears, shaft parts).

Machining process inspection

Dimensional and form tolerances:

- After rough machining: calipers and micrometers check the blank allowance.

- After finishing: Coordinate Measuring Machine (CMM) to verify the accuracy of complex surfaces and holes; Pneumatic Gauge to detect the diameter of inner holes.

- Surface quality: Roughness meter (Ra value detection), optical projector to observe microscopic scratches.

Heat treatment and surface treatment inspection

Hardness testing:

- Rockwell hardness tester (HRC): surface-hardened parts (e.g. gear tooth surfaces).

- Brinell hardness tester (HBW): tempered shaft parts.

- Thickness of carburizing/nitriding layer observed by metallurgical microscope (cutting of specimen is required).

- Coating adhesion: Scratch method to test the bonding strength of plating or coating layers.

Final and factory inspection

Function test:

- Gear mesh test: noise, transmission efficiency on a special stand.

- Sealing test: Pneumatic/hydraulic test (e.g. hydraulic valve block).

Non-destructive testing:

Magnetic Particle Flaw Detection: Detects surface cracks (for cast iron parts).

Ultrasonic Flaw Detection: Detection of internal porosity, inclusions (e.g. large castings).

X-ray inspection: Complex structure internal defects (such as welded parts).

Packaging and Traceability

- Anti-corrosion test: Salt spray testing machine simulates environmental corrosion (48-96 hours).

- QR Code Traceability: Record testing data, production batch to ensure traceability.

Key test equipment and tools

Detection items	Equipment/tools	Application Example
Dimensional accuracy	Coordinate measuring machine, digital calipers	Gear Pitch, Shaft O.D.
Surface Roughness	Roughness Gauges, Comparison Blocks	Hydraulic Cylinder Walls, Bearing Fitting Surfaces
Hardness	Rockwell/Brinell/Vickers	Hardened Gears, Tempered Drive Shafts
material composition	Direct Reading Spectrometer, Carbon and Sulfur Analyzer	Verification of Chromium Content in 40Cr Steel
Internal Defects	Ultrasonic Flaw Detectors, X-Ray Machines	Porosity in castings, unfused welds
Metallographic Organization	Metallographic microscope, specimen cutter	Ductile iron spheroidization rate, carburized layer microstructure

Common Test Standards

1. International/national standards

- Dimensional tolerances: ISO 2768 (general tolerances), GB/T 1804 (unnoted tolerances).

- Hardness standard: ISO 6508 (Rockwell hardness), ASTM E10 (Brinell hardness).

- Non-destructive testing: ISO 9712 (personnel qualification), GB/T 9443 (magnetic particle testing of cast steel parts).

2. Industry-specific requirements

- Gear accuracy: AGMA 2000 (American Gear Manufacturers Association standard).

- Welding quality: AWS D1.1 (American Welding Society standard).

Typical part inspection points

1. Gear parts

-Inspection items: tooth shape error (involute), tooth deviation, tooth surface hardness (HRC 58-62), depth of carburized layer (0.8-1.2mm).

-Equipment: Gear measuring center, hardness tester, metallurgical microscope.

2. Shaft parts

- Testing items: radial runout (≤0.02mm), keyway symmetry, surface roughness (Ra≤1.6μm), tempering hardness (HB 220-250).

- Equipments: Polarimeter, CMM, Magnetic Particle Flaw Detection Machine.

3. Shell parts

- Testing items: hole system coaxiality (≤Φ0.05mm), flatness (0.1mm/m), sealing surface roughness (Ra≤3.2μm).

- Equipment: pneumatic measuring instrument, laser tracking instrument.

Quality testing optimization recommendations

1. Automated inspection: Introduce machine vision system (e.g. AI image to recognize surface defects).

2. Data management: Integrate inspection data through MES system to monitor the qualification rate in real time.

3. Personnel training: Regular assessment of NDT (UT/MT/PT) personnel qualification.

4. Environmental control: Constant temperature laboratory (20±1℃) to ensure precision measurement accuracy.

Common Problems and Solutions

Problem	Cause Analysis	Solution
Uneven hardness of the gear tooth surface	Inconsistent quench cooling rate	Optimization of the quenching medium circulation system
Bending deformation of shaft parts	Heat treatment stress insufficient release	Addition of stress relief annealing process
Internal porosity in casting	Too low temperature or poor venting during casting	Improve mold design, increase risers

Through rigorous quality testing, the reliability, longevity and safety of agricultural machinery parts can be significantly improved, reducing the failure rate of field operations.

We will formulate targeted inspection programs in conjunction with product characteristics and continue to optimize our processes.