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Technical condition of steel bar for internal combustion engine valve (GB/T 12773-1991)
Internal combustion engine valves are essential components of internal combustion engines and are the control elements for the formation of the combustion chamber volume. It is necessary to pass a certain amount of gas from the engine cylinder to the cylinder head, so that the compression and exhaust of the engine can be completed smoothly, and the driving force of the engine can be utilized.
If the technology of the steel bar used in the manufacturing of the internal combustion engine valve does not meet the requirement of GB/T 12773-1991, it can cause serious troubles such as air leakage damage, so it is particularly important to select the optimal steel bar material. The technical conditions of steel bars for internal combustion engine valve according to GB/T 12773-1991 are as follows:
1. The chemical composition and mechanical properties of steel bars conform to the standards of standard grades in the latest version of GB/T 699 Steel Bar Quality and Technical Conditions.
2. Chemical composition inspection is carried out according to the requirements of GB/T 223steel and iron chemical analysis method.
3. The surface quality of the steel bar is in line with the GB/T 11253 steel external surface quality.
4. The surface hardness requirements of the steel bar are in line with the requirements of GB/T 14502 internal combustion engine valve steel surface hardness.
5. Steel bars that have been subjected to cold or hot treatment shall be required to be cleaned, surface-treated and thoroughly inspected, and they shall meet the following requirements:
(1) The surface of the steel bar must be smooth, free of welding defect and contamination;
(2) The surface hardness of the steel bar must be in line with the requirements of GB/T 14502 internal combustion engine valve steel surface hardness.
6. In accordance with the provisions of GB/T 14502internal combustion engine valve steel surface hardening, non-quenched steel bars must be subjected to surface hardening treatment, and the surface hardness must meet the requirements of the industrial standard.
7. Non-quenched and quenched-tempered steel bar have been subjected to hydrogen embrittlement treatment to reduce or eliminate the tendency of hydrogen embrittlement. The hydrogen embrittlement treatment generally includes preshrinking, high-temperature hydrogen embrittlement and low-temperature hydrogen embrittlement.
8. The steel bars used for internal combustion engine valves are smelted in vacuum induction furnaces and subgo the spheroid graphite process, with the nodule diameter ≥4mm, and the mechanical properties of the finished steel bar must meet the requirements of GB/T 699-2015 grade 10 80-100.
9. The delivery length size of steel bars used for internal combustion engine valves is 6.0m - 8.0m.
10. Non-conforming steel bars shall be transacted in accordance with the provisions of GB/T 12775steel nonconforming agreement transaction and return.
In addition to the technical requirements of the internal combustion engine valve steel bar stipulated in GB/T 12773-1991, the specification of the steel bar used for the processing of the valve is also important. Therefore, when purchasing the steel bar for the internal combustion engine valve, the processing specification, chemical composition and mechanical properties of the steel bar should be paid special attention to, and in-depth communication and cooperation with the suppliers should be conducted to ensure the quality of the steel bar used in the manufacturing.
