Elaboration of a production technology of K60 strength class flat rolled products for pipe lines connection details in normalized state
| Autor: | Yu. I. Matrosov, Alexey Kholodnyi, M. Yu. Matrosov, L. V. Prokopenko, S. P. Zubov, O. V. Samokhina, D. V. Nizhel’skii, A. A. Pridein |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information. 76:234-241 |
| ISSN: | 2619-0753 0135-5910 |
| DOI: | 10.32339/0135-5910-2020-3-234-241 |
| Popis: | The technology of manufacturing pipe lines connection details of K60 strength class due to a flow chart, used at plants, includes hot stamping, welding and thermal treatment to ensure the specified complex of mechanical characteristics. The technology allows obtaining the details with high strength properties. Still the process of thermal treatment includes a labor-intensive quenching operation followed by high tempering, which increases significantly the production process cycle and increases scattering of properties among the details within a manufactured batch. Besides, at the quenching of thick-walled fittings, a local change of the detail geometry can happen caused by cooling with different speeds. Results of the study of thermal treatment influence, simulating heating before hot stamping and post-welding tempering, taking place at the connection details manufacturing by a specific technology considered. This technology excludes quenching for mechanical properties of thick rolled product of low carbon steel, alloyed by copper. The temperature parameters of the treatment determined to ensure obtaining properties of K60 strength class and high impact toughness (KCV –40 ≥200 J/sm 2 ) of 10–50 mm thick flat rolled product. It was shown, that for the studied steel the optimal complex of K60 strength class properties is obtained after treatment due to heating modes before stamping at 830–860 °С, followed by a high tempering at 600 °С. The thermal treatment of both sheets and 10, 16, 20, 40 and 50 mm thick plates due to elaborated modes ensured mechanical properties of K60 strength class and high resistivity against impact bending at negative temperatures. Series of tests for impact bending of 10 mm thick plate showed a high cold-resistance of the steel, as follows: KCV –50 ≥200 J/sm 2 , % В (KCV –50 ) ≥90 %, Т 50 = –55 °С. |
| Databáze: | OpenAIRE |
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