tailieunhanh - The Science and Technology of Materials in Automotive Engines Part 12

Tham khảo tài liệu 'the science and technology of materials in automotive engines part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Glossary 263 Malleability This term is used when plastic deformation occurs as the result of applying a compressive load. The plastic deformation under a tensile load is referred to as ductility. Patenting An isothermal heat treatment applied to medium- and high-carbon steel wire prior to its final drawing operation. This process generates steel wire having high tensile strength. This produces strong wire such as piano wire. Patenting consists of passing the wire through tubes in a furnace at about 970 C. After austenitizing the wire at 970 C and the rapid cooling to 550-600 C generate a very fine pearlitic microstructure. The resulting ferrite with a fine distribution of carbide has a very high ductility and can be cold drawn with total reduction in diameter of 90 . The cold drawn wire may achieve tensile strength levels in excess of GPa without becoming brittle. Phase A homogeneous portion of a system that has uniform physical and chemical characteristics. Precipitation A phenomenon in which a crystal of a different phase is separated from a solid solution and grows. Quenching Operation which consists of cooling a ferrous product more rapidly than in still air. The use of the term specifying the cooling conditions is recommended for example air-blast quenching water quenching step quenching etc. Residual stress A stress that exists inside metal though no external force or thermal gradient is acting. When a heat treatment is carried out thermal stress or transformation stress due to the difference of cooling rate is produced inside and outside of the material and these combined remain inside the material as stress. The residual stress is also produced by cold working welding forging etc. Segregation A phenomenon in which alloying elements or impurities are unevenly distributed or its state. Single crystal A crystalline solid for which the periodic and repeated atomic pattern extends throughout the crystal. A single crystal does not include grain boundaries. .