As core components, engine cylinder blocks and cylinder heads must withstand high temperatures and pressures, ensure reliable sealing, and offer good assembly compatibility. Their technical indicators, including hardness testing and dimensional accuracy testing, all require strict control using precision equipment. The hardness testing of cylinder blocks and heads is mainly used to evaluate the mechanical properties of materials, ensuring they meet design requirements.
Rockwell hardness testers are suitable for hardness screening of large, flat surfaces such as cylinder block planes (e.g., cylinder head mating surfaces, cylinder block bottoms) and crankshaft hole end faces. For online quality inspection in production lines, customized testing requirements can be provided. Fully automatic Rockwell hardness testers can be integrated with the production line to achieve unmanned operation, featuring high efficiency and stable results. This testing method is the most commonly used in the mass production of automotive components and complies with the ISO 6508 and ASTM E18 standards.
Brinell hardness testers are applicable for hardness testing of cylinder block blanks and thick-walled parts (e.g., cylinder block sidewalls), and are particularly suitable for evaluating the casting quality and heat treatment effectiveness of cast iron cylinder blocks. It should be noted that Brinell testing leaves large indentations, so it should be avoided on easily damaged parts such as cylinder wall inner surfaces and precision-machined surfaces.
Vickers hardness testers are suitable for hardness testing of thin-walled parts of aluminum alloy cylinder blocks, cylinder liner inner surfaces (to avoid damaging the sealing surfaces), as well as hardness gradient testing of heat-treated layers and coatings (e.g., nitrided layers, quenched layers) on cylinder block surfaces. This testing method meets the precision testing needs of aerospace and high-end automotive engines, and complies with the ISO 6507 and ASTM E92 standards.
According to cylinder blocks and cylinder heads made of different materials, the following hardness scales can be referenced:
| Component | Common Materials | Hardness Reference Range (HB/HV/HRC) | Core Testing Purpose |
| Cast Iron Cylinder Block | HT250/HT300 (Gray Cast Iron), Vermicular Graphite Iron | 180-240HB20-28HRC | Ensure wear resistance and deformation resistance |
| Aluminum Alloy Cylinder Block | A356+T6, AlSi11Cu2Mg | 85-130 HB90-140 HV
15-25 HRC |
Balance strength and machinability |
| Cast Iron Cylinder Head | HT200/HT250, Ductile Iron | 170-220 HB18-26 HRC | Withstand high-temperature impact and ensure sealing surface tightness |
| Aluminum Alloy Cylinder Head | A356+T7, AlSi12Cu1Mg1Ni | 75-110 HB80-120 HV
12-20 HRC |
Balance lightweight property, heat dissipation and structural strength |
To the diverse testing requirements of engine cylinder blocks, Laizhou Laihua can provide customized solutions based on specific products. This includes standard models, customized models of the full range of Rockwell, Brinell, and Vickers hardness testers, as well as the design of exclusive fixtures tailored to products—all aimed at enhancing testing performance and measurement accuracy.
Post time: Dec-04-2025
