What is the core difference between castings and forgings?

Castings are formed by pouring molten metal. They feature complex shapes and low cost, suitable for shells and bases. Forgings are shaped by hot forging and extrusion with compact internal structure, high strength and toughness, applied to load-bearing and key transmission parts.

Which auto parts are castings and which are forgings?

Castings: engine block, gearbox housing, wheel hub, brake disc, brackets. Forgings: crankshaft, connecting rod, steering knuckle, half shaft, gear, suspension arm.

General warranty standard for parts?

Normally 3 years or 100,000 kilometers along with vehicles. Wear parts follow separate terms. Non-artificial damage and material defects are covered by after-sales service.

Causes of surface air holes and sand holes?

Excessive gas in molten metal, poor mold ventilation, damp molding sand and improper pouring speed. They weaken sealing performance and structural strength.

How to judge if cracked castings are scrapped?

Penetrating cracks and cracks on stress-bearing positions shall be scrapped directly. Shallow fine cracks can be repaired and used after inspection if no extension exists.

Solutions to casting distortion and warpage?

Caused by uneven cooling stress. Small parts can be reshaped; slight deformation of large parts can be corrected by machining. Excessively deformed products shall be discarded.

Measures against poor corrosion resistance and rusting?

Conduct painting, electrophoresis and oil immersion protection. Keep dry storage and apply anti-rust packaging before delivery.

Impact of surface peeling and folding defects?

Shallow peeling can be polished off. Folding is deep defect which easily causes fracture under stress and shall not be assembled on vehicles.

Reasons for unqualified hardness?

Deviated forging, quenching and tempering temperature. Excessively hard parts tend to crack, while soft ones wear and deform easily.

Control of dimensional deviation?

Caused by worn molds and unstable forging pressure. Inspect molds regularly and conduct full dimension test on first finished products.

Hidden dangers of internal porosity and impurities?

Destroy metal compactness and lead to fracture under high-speed operation and load bearing. Ultrasonic inspection is mandatory.

Can castings and forgings be replaced mutually?

Not allowed for key load-bearing parts. Simple non-stress brackets can be replaced if parameters meet standards.

Suitable machining allowance?

2-4mm unilateral allowance for castings, 1-2mm for forgings to balance precision and strength.

Damage prevention under high temperature working condition?

Adopt high-temperature resistant materials, optimize heat dissipation and regularly check deformation, cracks and wear.

Key inspection items upon receipt?

Appearance defects, dimensional tolerance, hardness report, flaw detection certificate, material grade and surface protection layer.

Sampling inspection ratio for bulk goods?

5%-10% for regular batches. Full visual inspection and random flaw detection for critical safety parts.

After-sales disposal of unqualified parts?

Free return and replacement for defective products caused by material and process problems. Manually damaged parts can be repaired or sold at discount via negotiation.

Anti-rust validity period?

6-12 months under dry environment with standard packaging. Recheck and reprocess rust prevention within 3 months in humid conditions.

Methods to avoid deformation caused by stacking pressure?

Store by category and layers. Pad heavy parts separately and avoid heavy stacking.