What 's The Difference Of Steel Material Grade Q195 Q235 Q355 ?

The Q195, Q235, and Q355 steel grades are all part of the carbon steel family, but they differ in their chemical composition, mechanical properties, and applications. Here's a detailed comparison of these three material grades:

Q195 Steel Grade

Chemical Composition: Q195 steel has a carbon content ranging from 0.06% to 0.12%, with manganese (Mn) up to 0.50%, silicon (Si) up to 0.30%, phosphorus (P) up to 0.035%, and sulfur (S) up to 0.040%.

 

Mechanical Properties: It has a yield strength of 195 MPa and a tensile strength ranging from 315 to 430 MPa. The elongation percentage is around 33% for samples with a diameter less than or equal to 40mm.

 

Applications: Due to its low strength but high plasticity, toughness, and weldability, Q195 is used for general structural purposes, manufacturing wire rods, steel plates, and pipes. It's also used in roofing panels, decorative panels, and packaging containers.

Q235 Steel Grade

Chemical Composition: Q235 steel has a slightly higher carbon content than Q195, ranging from 0.14% to 0.22% for Q235A and up to 0.20% for Q235B. It also contains up to 1.40% manganese, up to 0.35% silicon, and phosphorus and sulfur up to 0.045% and 0.050% respectively.

 

Mechanical Properties: The yield strength for Q235 is 235 MPa, with a tensile strength ranging from 370 to 500 MPa. The elongation percentage is around 26% for samples with a diameter less than or equal to 40mm.

 

Applications: Q235 steel is used in structural and engineering applications that require moderate strength. It's commonly rolled into various shapes like wire rods, angles, channels, and plates used in construction, vehicles, bridges, and boilers.

Q355 Steel Grade

Chemical Composition: Q355 steel, a low alloy high-strength steel, has a carbon content typically ranging from 0.20% to 0.25% for Q355B. It contains up to 1.40% manganese, up to 0.30% silicon, and phosphorus and sulfur up to 0.035% and 0.040% respectively.

 

Mechanical Properties: With a minimum yield strength of 355 MPa, Q355 steel has a tensile strength range of 470-630 MPa. The elongation percentage is around 22%, and it has good impact resistance, with Q355D capable of withstanding temperatures as low as -20°C.

 

Applications: Q355 steel is used in heavy-duty applications such as bridges, high-rise buildings, and heavy machinery due to its high strength and toughness. It's also used in the manufacturing of ships, pressure vessels, and other structural components that require high load-bearing capacity.

 

In summary, while Q195 is suitable for general purposes where high ductility and formability are needed, Q235 offers a balance of strength and formability for moderate load-bearing applications. Q355, with its higher strength and toughness, is ideal for heavy-duty applications requiring robust structural integrity. Each grade has its specific uses based on the required strength, formability, and environmental conditions of the project.