Вибір матеріалу, маршрутної технології виготовлення та термічної обробки деталі "втулка"

Abstract

Кваліфікаційна робота на здобуття кваліфікації бакалавр зі спеціальності 132 – Матеріалознавство. Сумський державний університет. Суми, 2022. Проаналізовані основні аспекти умов роботи деталі «втулка» головного циркуляційного насосу. Проведений аналіз експлуатаційних властивостей виробу. Призначено матеріал сталь 25Х17Н2Б-Ш. Розроблена поетапна маршрутна технологія виготовлення деталі. Вдосконалено базовий варіант термічної обробки деталі «втулка». Запропонована термічна обробка складається з операцій: відпал, гартування, обробка холодом і подвійний відпуск. Проаналізовані мікро- та макроструктура визначені твердість обраної сталі після термічної обробки. Проведені випробування на стійкість до міжкристалічної корозії.

Qualifying work of a bachelor in specialty 132 - Materials Science. Sumy State University. Sumy, 2022. The bachelor's thesis contains: 67 pages, including 10 tables, 20 figures, a list of 36 used sources on 3 pages, 7 appendices on 8 pages. The purpose of the work is the purpose of the material of the "sleeve" part of the main circulation pump, as well as the development of route technology for the manufacture and heat treatment of the "sleeve" part. Thus, the author of the work took steps to achieve the above goal: 1. The part "sleeve" is considered, as well as the main circulating pump 195M, in which the part operates, describing the purpose and operating conditions of the part. Also, the analyzed material is generalized, and the necessary operational characteristics of the part are formulated. 2. A critical analysis of literary sources. The main methods of improving the characteristics and properties of steel 25Cr17N2Nb-Sh by adding alloying elements and conducting modern heat treatment operations are analyzed. 3. Steel was selected for the manufacture of this part, as well as micro- and macroanalysis, hardness measurements and tests for susceptibility to IGC. 4. Developed a modern technological process of manufacturing parts "sleeve". The following sequence of operations is offered: ore extraction; obtaining cast iron; steel smelting; obtaining a blank; heat treatment; obtaining parts, non-reinforcing heat treatment (low tempering). 5. Equipment for heat treatment of this steel is selected. The main causes of failure are mechanical wear, cyclic fatigue, corrosion, cavitation wear and intergranular corrosion. Requirements for the finished product: yield strength (σ0,2) is 1175 MPa, temporary resistance (σV) - 1470 MPa, elongation (δ) not more than 8%, relative narrowing (ψ) not more than 45%, impact in viscosity (KCU) - 50 J / cm2, hardness (HRC) - 28. The work is related to the study of the effect of heat treatment on the corrosion resistance, strength and toughness of the NCP bushing, made of high quality steel 25Cr17N2Nb-Sh. The reliability of the performance of such parts is determined primarily by the yield strength, elongation and narrowing, toughness, resistance to intergranular corrosion and hardness of the material from which the part is made. The technology of production and heat treatment of the 25Cr17N2Nb-Sh steel pump hub was recommended and implemented in the production conditions of KOMPRESORATOMMASH LLC (Appendix A). The main results of the work are implemented in the educational process at the Faculty of Technical Systems and Energy Efficient Technologies of Sumy State University in the courses "Metallurgy and Basics of Heat Treatment", "Corrosion and Protection of Materials", "Alloy Steels and Alloys", "Mechanical Properties and Wear Resistance of Materials and Products" specialty 132 "Materials Science". It was determined that the final structure of steel 25Cr17N2Nb-Sh martensite and austenite. Defects identified central porosity and total spot liquation score 1. In addition, oxide point score 1 was detected. The hardness of steel 25Cr17N2Nb-Sh after heat treatment is 28 НRC, which satisfies the basic requirements for the part "sleeve". Steel 25Cr17N2Nb-Sh after the recommended heat treatment proved to be resistant to IGC.