High requirements for the physical and mechanical properties of precision steels impose special responsibility on the production stages of the presented materials.
The presence of increased requirements for the purity of the chemical composition and the accuracy of the physical and mechanical characteristics of precision alloys hinders the development of a unified technological algorithm for smelting. In some cases, it is necessary to introduce additional production steps, such as:
- selection of the optimal batch composition;
- choosing the right working environment;
- use of specific remelting methods (electroslag, plasma, electron beam, etc.).
Among special smelting technologies, vacuum-induction is the most common. It involves induction heating of the prepared batch in vacuum-induction furnaces. It is mainly used in the production of billets that will later be re-melted. When marking steels, it is indicated by the letters VI, for example, alloy 49K2FA-VI.
Special smelting methods
In addition to vacuum-induction technology for smelting billets, there are other special methods:
- plasma-arc smelting method — metal is melted in special plasma furnaces, where the energy source is ionized inert gas heated to a certain temperature, mainly argon; this method is recommended for smelting heat-resistant precision alloys and steels with a high nitrogen content;
- electron beam melting — the metal is heated due to the flow of accelerated electrons created by special electronic guns;
- electroslag smelting method — makes it possible to improve the quality of the material produced; melting is carried out in a bath of electrically conductive slag, which is heated by electric current;
- vacuum-arc method — makes it possible to obtain blanks with a dense and homogeneous macrostructure and a minimum amount of harmful impurities.
The chemical composition of precision alloys is regulated by GOST 10994-74. This document defines the maximum allowable quantitative indicators alloying elements and harmful contaminants.
Precision casting technologies
As part of the production of precision alloys, it is planned to use various smelting technologies. Specifically:
- Refractory castings. The process involves pouring molten metal into special molds made from a mixture of purified sand and specialized refractory resins. It allows you to create parts with high accuracy and stable chemical composition.
- Centrifugal casting method. It helps to ensure an even distribution of the material composition under the influence of centrifugal force. The molten metal is poured into the cavity of the rotating plate and is evenly distributed in the casting molds through special channels.
- Use of silicate molds for smelting blanks. This method makes it possible to obtain products from precision alloys of specified dimensions and precise geometric shapes. Silicate molds ensure excellent surface quality and minimize deformations.
GOST 10994-74 also contains recommendations for choosing certain steel grades for the production of products of various shapes, in particular thin wire or cold rolled strip.
Methods for improving the performance of metals
The damage that precision alloy products undergo during operation can be caused by various factors. One of the main ones is metal corrosion and surface oxidation. Such damage can lead to a deterioration in the physical and mechanical characteristics of steels and the loss of performance of complex components and assemblies.
For corrosion prevention and metal protection the following methods are used:
- Hot treatment in vacuum or inert gas. This method makes it possible to process the melted workpieces under conditions that exclude contact with air and moisture, which significantly reduces the risk of corrosion and oxidation. This treatment ensures the preservation of the quality of the metal and its durability.
- Directed crystallization technology. This process contributes to a more uniform and orderly growth of the metal's crystal structure, which improves its mechanical properties and resistance to corrosion.
- Thermomagnetic, thermomechanical or thermal treatment in vacuum or hydrogen. These processing methods make it possible to improve the structure and properties of the metal, making it more durable and resistant to aggressive effects.
St. Petersburg Precision Alloy Plant produces cold-rolled strip from various steel grades with precise chemical composition in accordance with GOSTs or customer specifications. For cooperation questions, please contact specified phones or leave requests on the site. Our engineers will contact you with full details about manufactured products.
