Steel Standards (e.g., GB/T 700 Q215A)
In the Chinese standard (GB/T 700), Q215A is a carbon structural steel.
Q: "Yield," indicating yield strength.
215: Minimum yield strength of 215 MPa.
A: Quality grade (A is the basic grade, with lower impact resistance requirements than B, C, or D).
Used for general construction, piping, or low-stress structural components.
1. Classification of Carbon Steel
(1) Classification by Carbon Content
Type Carbon Content (%) Characteristics and Applications
Low Carbon Steel 0.05~0.25 Good plasticity, easy to weld, used for cold rolled plates, steel bars, car bodies, etc.
Medium Carbon Steel 0.25~0.60 High strength, used for mechanical parts (gears, shafts, etc.)
High Carbon Steel 0.60~2.10 High hardness, wear resistance, used for tools, springs, rails, etc.
(2) Classification by Application
Structural Steel: used for buildings and bridges (such as Q235, A36).
Tool Steel: used for tools and molds (such as T8, T10).
Special Purpose Steel: such as boiler steel, shipbuilding steel, etc.
(3) Classification by Smelting Method
BOS Steel: such as ordinary carbon steel (Q series).
EAF Steel: such as high-quality carbon steel (45#, 20#). 2. Carbon Steel Grades (Comparison of Domestic and International Standards)
(1) Chinese Standard (GB)
Grade Type Application
Q195 Low Carbon Steel Sheet, Wire
Q235 Low Carbon Steel Building Structures
45# Medium Carbon Steel Mechanical Parts
T8/T10 High Carbon Steel Cutters, Saw Blades
(2) American Standard (ASTM/AISI)
Grade Type Application
A36 Low Carbon Steel Structural Steel
1045 Medium Carbon Steel Shaft Parts
1095 High Carbon Steel Cutters, Springs
(3) International Standard (ISO/DIN/EN)
S235JR (European Standard, Similar to Q235)
C45 (German Standard, Similar to 45#)