In the steel industry, CQ (Commercial Quality), DQ (Drawing Quality), HSS (High - Strength Steel), and FH (Fully Hardened Steel / Ultra - High - Strength Steel) are different categories classified based on the forming properties, strength levels, application scenarios, etc. of the steel. Their performance indicators vary significantly, and the following is a detailed analysis:
1.Core classification criteria and application scenarios
|
classification |
Classification dimensions |
Typical application scenarios |
|
CQ |
Forming performance (lowest level) |
Simple stamped parts (such as home appliance casings, iron drums), building structural components |
|
DQ |
Forming performance (intermediate to advanced level) |
Complex stamped parts (such as automotive fuel tanks, inner door panels), deep - drawn parts |
|
HSS |
Strength grade (medium - strength) |
Automotive lightweight structures (such as vehicle frames, bumpers), construction machinery, bridges |
|
FH |
Strength grade (ultra - high strength) |
High - load - carrying structures (such as offshore platforms, mining machinery), ship decks, ballistic equipment. |
2.Summary of key differences
|
Performance indicators |
CQ |
DQ |
HSS |
FH |
|
Yield strength |
(≤370MPa) |
(140-420MPa) |
(210-550MPa) |
(≥355MPa) |
|
Tensile strength |
(300-400MPa) |
(270-680MPa) |
(350-780MPa) |
(550-940MPa) |
|
Elongation after fracture |
(≥28%) |
(18-30%) |
(16-35%) |
(≤21%) |
|
Impact toughness |
Generally, there is no requirement. |
Some require impact energy at -20℃. |
Normal temperature or low temperature (for some) |
Low temperature (-40℃ to -60℃) |
|
Core advantages |
Low cost and easy to form |
Deep drawability, anti - deformation |
Lightweight and medium - strength |
Ultra - high strength and resistance to extreme loads |
3.As can be seen from the above comparison, the differences in strength, plasticity, toughness, etc. among steel products of different grades directly determine their application scenarios. When making a choice, factors such as forming requirements, load conditions, and cost need to be considered comprehensively.
