1. Employing appropriate cooling methods:

The cooling process following metal quenching significantly influences deformation. Hot oil quenching results in less distortion than cold oil quenching, typically maintained at 100±20°C. The cooling capacity of the oil is also crucial to deformation.

Both the agitation method and cooling rate during quenching influence deformation. Faster cooling rates in metal heat treatment result in more uneven cooling, generating greater stresses and consequently larger deformation in the mould. Where possible, pre-cooling should be employed whilst ensuring the required mould hardness is met. Graded cooling quenching significantly reduces thermal and structural stresses generated during quenching, proving an effective method for minimising deformation in complex-shaped components. For exceptionally intricate or high-precision parts, isothermal quenching can markedly reduce deformation.

2. Selecting Suitable Media:

Where equivalent hardness requirements are met, prioritise oil-based media. Experimental and practical evidence indicates that, under otherwise identical conditions, oil-based media exhibit slower cooling rates compared to water-based media. Furthermore, water-based media are more susceptible to temperature fluctuations affecting cooling characteristics. Under identical heat treatment conditions, oil-based media generally yield lower deformation rates post-quench compared to water-based media.

3. Rational part design:

During cooling after metal heat treatment, thinner sections invariably cool faster than thicker sections. Where practical production requirements permit, significant thickness variations within workpieces should be minimised. Part cross-sections should strive for uniformity to reduce distortion and cracking tendencies arising from stress concentration in transition zones. Workpieces should maintain structural symmetry in material composition and microstructure to minimise distortion from uneven cooling. Sharp edges, grooves, and similar features should be avoided; transitions between thicknesses and steps should incorporate rounded corners. Asymmetrical hole and groove structures should be minimised. For parts with non-uniform thickness, allowances for subsequent machining should be incorporated.

Bearing maintenance: To maintain bearings in optimal condition for the longest possible duration, regular maintenance and inspection are essential to prevent failures proactively, ensure operational reliability, and enhance productivity and cost-effectiveness.

Maintenance should ideally follow operational standards tailored to the machinery's running conditions and be performed periodically. This includes monitoring operational status, replenishing or replacing lubricants, and conducting periodic disassembly inspections. Operational inspection items encompass bearing rotation sounds, vibration, temperature, and lubricant condition.

Bearing Inspection: Bearing Cleaning: When disassembling bearings for inspection, first document their external condition, assess residual lubricant quantity, and take lubricant samples for analysis before proceeding with cleaning. Common cleaning agents include petrol or kerosene.

Cleaning disassembled bearings involves coarse and fine cleaning stages. Place bearings in separate containers lined with metal mesh to prevent direct contact with container debris. During coarse cleaning, care must be taken to avoid rotating the bearing with contaminants attached, as this may damage the rolling surfaces. Use a brush to remove grease and adhering substances from the coarse cleaning oil. Once largely clean, proceed to fine cleaning.

Fine cleaning involves rotating the bearing in cleaning oil while meticulously washing it. Additionally, the cleaning oil must be kept clean at all times.

Bearing Inspection and Assessment: To determine whether a disassembled bearing remains serviceable, inspect it thoroughly after cleaning. Examine the condition of the raceways, rolling surfaces, and mating surfaces; assess cage wear; check for increased bearing clearance; and identify any damage or abnormalities indicating reduced dimensional accuracy. For non-separable small ball bearings, support the inner ring horizontally with one hand and rotate the outer ring to verify smoothness.