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25RC12
YASSIAN or Your's
Testing methods for surface hardness of bucket teeth in construction machinery
According to the technical requirements for the surface hardness testing of bucket teeth in construction machinery, and in combination with different working conditions and precision demands, the testing methods are classified and explained as follows:
I. Conventional Hardness Testing Methods
Leeb/Shore hardness method
It is suitable for direct measurement of tooth surfaces. When using a Leeb hardness tester (such as the PHR-G6 type) : Select a matching material indenter → push the loading sleeve to lock the impact body → the probe presses vertically against the tooth surface → trigger the measurement and read the HRC value.
Advantages : Easy to operate, suitable for on-site rapid detection; Youdaoplaceholder0 limitation : The accuracy is affected by the surface curvature, and multiple measurements are required to take the average.
Vickers hardness method (laboratory high precision)
In accordance with the GB/T 4340.1-2023 standard: Diamond square pyramid indenter is adopted, the test force range is 1- 100 kgf, the measurement accuracy of the diagonal of the indentation is ±0.5 μm→ calculate the HV value.
Key point : When conducting depth detection of the hardened layer, dots should be made perpendicularly to the tooth surface at the pitch circle in the middle of the tooth width, with a spacing of no less than 2.5 times the diagonal of the indentation, and a hardness gradient curve should be drawn.
Rockwell hardness method (end face assisted testing)
When the tooth surface space is limited, measure the arc parts of the tooth root on both sides of the gear end face instead: Use the HRC scale, preload 98.07N, and the hardness value fluctuation should be ≤5 HRC units.
Ii. Special Working Condition Detection Plan
Scene method Technical points
Cladding layer inspection microscopic Vickers hardness method load ≤0.3 kgf, avoid cladding pores, measure the hardness gradient near the fusion line
Thin-walled bucket teeth (< 1.6mm) small load Vickers method in accordance with ISO 6507-1:2018, test force 0.5kgf, base interference correction
The wear pits on the surface of the worn tooth tip were ground flat by Rockwell method (HR15N scale), with a preload of 29.42N, and the hardness of the residual hardened layer was measured
Iii. Quality Control Standards
Hardness range : working surface of tooth tip 58-65 HRC (new parts), ≥50 HRC after service;
Gradient requirement : the hardness difference from the tooth tip to the matrix transition zone ≤15% HV;
Tolerance control : the hardness fluctuation of bucket teeth in the same batch is ≤5 HRC, and the re-measurement rate of abnormal points is ≥30%.
Failure correlation : when the tooth surface hardness is less than 55 HRC, the wear rate increases by 300%; Uneven hardness of the fillet at the tooth root (δ>10%) is prone to cause fatigue cracks.
Testing methods for surface hardness of bucket teeth in construction machinery
According to the technical requirements for the surface hardness testing of bucket teeth in construction machinery, and in combination with different working conditions and precision demands, the testing methods are classified and explained as follows:
I. Conventional Hardness Testing Methods
Leeb/Shore hardness method
It is suitable for direct measurement of tooth surfaces. When using a Leeb hardness tester (such as the PHR-G6 type) : Select a matching material indenter → push the loading sleeve to lock the impact body → the probe presses vertically against the tooth surface → trigger the measurement and read the HRC value.
Advantages : Easy to operate, suitable for on-site rapid detection; Youdaoplaceholder0 limitation : The accuracy is affected by the surface curvature, and multiple measurements are required to take the average.
Vickers hardness method (laboratory high precision)
In accordance with the GB/T 4340.1-2023 standard: Diamond square pyramid indenter is adopted, the test force range is 1- 100 kgf, the measurement accuracy of the diagonal of the indentation is ±0.5 μm→ calculate the HV value.
Key point : When conducting depth detection of the hardened layer, dots should be made perpendicularly to the tooth surface at the pitch circle in the middle of the tooth width, with a spacing of no less than 2.5 times the diagonal of the indentation, and a hardness gradient curve should be drawn.
Rockwell hardness method (end face assisted testing)
When the tooth surface space is limited, measure the arc parts of the tooth root on both sides of the gear end face instead: Use the HRC scale, preload 98.07N, and the hardness value fluctuation should be ≤5 HRC units.
Ii. Special Working Condition Detection Plan
Scene method Technical points
Cladding layer inspection microscopic Vickers hardness method load ≤0.3 kgf, avoid cladding pores, measure the hardness gradient near the fusion line
Thin-walled bucket teeth (< 1.6mm) small load Vickers method in accordance with ISO 6507-1:2018, test force 0.5kgf, base interference correction
The wear pits on the surface of the worn tooth tip were ground flat by Rockwell method (HR15N scale), with a preload of 29.42N, and the hardness of the residual hardened layer was measured
Iii. Quality Control Standards
Hardness range : working surface of tooth tip 58-65 HRC (new parts), ≥50 HRC after service;
Gradient requirement : the hardness difference from the tooth tip to the matrix transition zone ≤15% HV;
Tolerance control : the hardness fluctuation of bucket teeth in the same batch is ≤5 HRC, and the re-measurement rate of abnormal points is ≥30%.
Failure correlation : when the tooth surface hardness is less than 55 HRC, the wear rate increases by 300%; Uneven hardness of the fillet at the tooth root (δ>10%) is prone to cause fatigue cracks.
