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- ordinary quality.,
- qualitative (general purpose).,
- special purpose.
Carbonaceous steel of ordinary quality are characterized by the considerable
content of harmful impurity, nonmetallic inclusions and gases. Steel of ordinary
quality let out in the form of hire.
Depending on the guaranteed properties of steel are subdivided into three
groups - A, B, C, on normalized indicators - on six categories. Mark them steel
letters. The indexes standing to the right of number of brand, mean rs-rimming,
sk-semi-killed and k.s. –killed steel. Between an index and number of brand
there can be a letter G that means the raised content of manganese. In
designations of brands to the left of letters of St groups (B and C, the group A is
not specified) steel.
For example, St5 Gsk-3 means: steel of group A, the St5 brand with the raised
content of manganese, semi-killed, the third category.
There were groups of steel A only with the guaranteed mechanical properties.,
are delivered in the annealed condition without hot processing. Their chemical
composition isn't regulated.
There were groups of steel B only with the guaranteed chemical composition.,
use for manufacturing of products with application of hot processing (punching,
forging).
Steel of group B have the guaranteed mechanical properties and a chemical
composition. They are widely applied by production of welded and other
designs.
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