Lecture № 5.
Carbon steel.
1. Classification of the steel
2. Tool steel. Steel with special properties.
3. Carbon steel of ordinary quality.
4. Carbon qualitative steel
5. Carbon tool steel. Carbon steel of the special purpose.
Classification of the steel.
Classification by the chemical composition.
Chemical composition of the steel is subdivided on:
- carbon (low-carbon to 0,2 % With, medium-carbon 0,2-0,45., high-carbon,
containing more than 0,5 % C).,
- alloyed (the sum of alloying elements at low-alloyed steel to 2,5 %., at
medium-alloy steel 2,5-10 %., at high alloy steel-more than 10 %).
The content of carbon don't accept in attention, at definition of degree of an
alloying, manganese and silicon are considered as alloying elements at their
contents more than 1 and 0,8 % respectively.
At designation of brands of steel use the following designations of chemical
elements: G-manganese, M-molybdenum, D-copper, R-pine forest, S-silicon, V-
tungsten, Yu-aluminum, P-phosphorus, N-nickel, F-vanadium, B-niobium, A-
nitrogen, H-chrome, Ts-zirconium.
For marking of steel is used a certain combination of figures and the letters
showing an approximate chemical composition of steel.
The first figures in brand of steel specify the content of carbon in the 100-th
shares of percent. If at the beginning of marking before letters there is one
figure, it expresses the content of carbon in the tenth shares of percent.
Further in marking the letters showing existence of the corresponding alloying
elements as a part of steel. Figures behind letters show average percentage of an
alloying element. Thus, if the maintenance of an element to 1,5 %, figure isn't
put.
For designation of the high-quality alloyed steel at the end of marking add the
letter "A". High-quality steel contains less sulfur and phosphorus, than
qualitative.
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