What are the advantages and disadvantages of Q345B steel compared to other steels?

What are the advantages and disadvantages of Q345B steel compared to other steels?
Q345B is a low-alloy, high-strength structural steel specified in the Chinese national standard (GB/T 1591). Compared to other types of steel (such as ordinary low-carbon steel, higher-strength low-alloy steel, and stainless steel), its advantages and disadvantages primarily focus on strength, workability, cost, and applicable applications. These advantages and disadvantages are as follows:
1. Compared to ordinary low-carbon steel (such as Q235)
Advantages:
Higher strength: Its yield strength (≥345 MPa) is significantly higher than that of Q235 (≥235 MPa). This allows for reduced thickness (weight reduction of 10%-30%) under the same load, making it suitable for lightweight structures (such as automotive chassis and steel structures).
Excellent overall mechanical properties: Containing microalloying elements such as Nb, V, and Ti, it combines strength with a certain degree of toughness (room-temperature impact energy ≥34 J). It also offers enhanced fatigue resistance and deformation resistance, making it suitable for components subject to dynamic loads (such as crane booms). Disadvantages:
Slightly higher cost: Due to the addition of microalloying elements, the price is 10%-15% higher than Q235.
Slightly more difficult to process: Cold bending and stamping require higher pressure, and thick plate welding requires controlled processing (such as preheating). Q235, on the other hand, requires almost no special processing, making it easier to process.
II. Compared with higher-strength low-alloy steels (such as Q355B and Q460)
Advantages:
Better weldability: The carbon content (≤0.20%) is lower than that of Q355B (≤0.24%) and Q460 (≤0.20%, but with more alloying elements). It has a lower tendency to harden during welding and a lower risk of cold cracking, making it suitable for automated batch welding (such as automobile frame welding).
Improved formability: The plastic reserve is slightly higher (elongation ≥22%, comparable to Q355B, but better than Q460's ≥17%). The risk of cracking during cold bending and hemming is lower, making it suitable for complex shapes (such as pipe elbows). Lower cost: 3%-5% lower than Q355B and 15%-20% lower than Q460, offering a better value for money.
Disadvantages:
Lower upper strength limit: Yield strength (345 MPa) is lower than Q355B (355 MPa) and Q460 (460 MPa), making it unsuitable for ultra-high pressure and ultra-heavy load applications (such as load-bearing arms of large construction machinery).
III. Compared with stainless steel (such as 304)
Advantages:
Much lower cost: The price is only 1/3-1/2 of 304 stainless steel, making it suitable for structural parts with low corrosion resistance requirements (such as factory steel columns).
Better balance of strength and workability: Higher strength than 304 (yield strength 205 MPa), and easier welding and cutting (stainless steel welding requires protection against intergranular corrosion).
Disadvantages:
Poor corrosion resistance: Contains alloying elements such as chromium and nickel, making it susceptible to rust and requiring surface treatments such as painting and galvanizing. Unsuitable for humid, acidic, and alkaline environments (such as chemical equipment).