To achieve the required mechanical and chemical characteristics spring-springs steels are alloyed with silicon, manganese, nitrogen, chromium and other components. Each of them has a certain impact on metal properties, and also makes it possible to increase their strength and elasticity, which, in turn, increases reliability rafting when operating under extreme conditions. For example:
If steel contains less than 2.5% of various additives, the alloy is low-alloy; from 2.5% to 10% is medium-alloyed, and more than 10% is high-alloy.
But even with the addition of all available alloying elements, it is impossible to obtain a super-strong metal that can operate in aggressive conditions for many decades without being destroyed. This is due to the fact that combinations of chemical elements behave differently in different proportions. So before getting a new brand steels, experts are conducting hundreds of experiments to understand how the new metal will behave under certain conditions.
Let's look at examples of how the same alloying additives make it possible to obtain alloys with different properties. And not only due to various additives, but also due to the peculiarities of production.
For example, steel grade 65S2VA contains at least 1.5% and not more than 2% of silicon, 0.8-1.2% of tungsten, suitable for the manufacture of critical and high-loaded springs. And here's steel 60S2A contains only 1.5% to 2% silicon and is more suitable for making collets, spring washers and torsion shafts.
The main difference lies in the material's hardness, yield strength and short-term strength. Moreover, the short-term strength limit for both metals will be different only after hardening, cooling in oil and subsequent tempering. In this case, it will be 1,570 MPa for 60C2A steel and 1,860 MPa for 65C2VA. But for cold rolled strip of both metals, it will be between 780 and 1,180 MPa. At the same time, Brinell hardness will vary regardless of production technology: for 60C2A — 269 MPa after annealing and 302 MPa without it; for 65C2VA — 285 MPa and 321 MPa, respectively.
Another example of how the same chemical element in combination with other additives can change the properties of an alloy. Steels 50HFA et 70S2HA they contain chromium, only in the first its amount is 0.8-1.1%, and in the second — 0.2-0.4%. 50HFA also contains vanadium in an amount of 0.1 to 0.2%, and 70C2HA contains silicon — from 1.4 to 1.7%. They also differ in the amount of carbon and manganese: in 50HFA, C = 0.46-0.54%, Mn = 0.5-0.8%; in 70C2HA, C = 0.65-0.75%, Mn = 0.4-0.6%.
All this gives them different physical and chemical properties, and, consequently, applications. 70S2HA is considered an alloy that is not prone to release brittleness and is ideal for making watch springs. But 50HFA already has a slight tendency to release brittleness, which leads to a decrease in impact strength. It is considered more suitable for the production of heavily loaded elements that will be operated at temperatures up to 300°C.
Each grade of spring steel has its own characteristics and the most suitable applications. In one article, it is difficult to talk about all the characteristics, advantages and disadvantages of different metals. If you need an alloy for specific production tasks, please contact us — we will help you choose the right material and tell you in detail about its properties and applications. We produce steels of various grades in the form of a cotton tape in full compliance with the set goals and current regulatory requirements.
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