Product Details Page for Medium and Thick Plate · Selection and Application Guidelines for Steel Plates for Engineering Structures
Product category: Medium thick plates (ordinary carbon plates, low-alloy high-strength plates, bridge plates, boiler vessel plates, etc.)
Execution standards: GB/T 709 (Dimensions, Shape, Weight and Allowable Deviation of Hot Rolled Steel Plates and Strips), GB/T 1591, GB/T 700, etc
Common specifications: Thickness of 8mm to 120mm, width of 1500mm to 3000mm, length can be customized according to requirements
1、 Core requirements for medium and thick plates in engineering structures
In the fields of building steel structures, bridge engineering, heavy machinery, and shipbuilding, medium thick plates bear the main functions of bearing and deformation resistance. Compared with thin plates, the processing difficulties of medium thick plates mainly focus on three aspects: welding deformation control, low-temperature impact toughness, and dimensional accuracy.
The key to selecting suitable medium thick plates lies in balancing strength, toughness, and weldability. For example, in outdoor steel structures in cold northern regions, it is necessary to focus on the low-temperature impact energy of the steel to prevent brittle fracture in winter; In large ship hulls, more attention is paid to the seawater corrosion resistance and welding efficiency of steel plates.
2、 Mainstream Material Series and Applicable Scenarios
According to the design requirements of different projects, medium thick plates are usually divided into the following series:
Material Classification
Representative brand example
Core Features
Typical application scenarios
High quality carbon structural steel
Q235B / Q255C
Good comprehensive mechanical performance and excellent weldability
Building factory columns, beams, and general mechanical bases
Low alloy high-strength steel
Q355B / Q355ND
High strength, better weather resistance than ordinary carbon steel
High rise buildings, cross sea bridges, heavy truck frames
Bridge specific steel
Q345qE / Q370qE
Excellent low-temperature impact toughness and resistance to layered tearing
Railway bridges, highway steel bridge decks
Boiler and container steel
Q245R / Q345R
High temperature and high pressure resistance, good organizational stability
Pressure vessel cylinder, power plant boiler steam drum
Selection Tips:
For components that require welding without heat treatment, priority should be given to materials with lower Ceq (carbon equivalent) to reduce cold crack sensitivity.
3、 Key production processes and quality control
To ensure the reliability of medium and thick plates in engineering applications, the production process needs to pay attention to the following technical indicators:
1. Rolling and controlled cooling technology
By using TMCP (Thermomechanical Control Process) or ACC (Accelerated Cooling) technology, the rolling and cooling rates are controlled to refine the grain size, improve the strength and toughness matching of the steel, reduce the amount of alloying elements added, and improve the welding performance.
2. Dimensional accuracy control
Strictly implement the GB/T 709 standard and control the thickness tolerance and unevenness (sickle bend) of steel plates.
For high-precision structural components, thickness tolerances of Class N (small positive deviation) or Class C (symmetrical positive and negative deviation) can be selected to reduce subsequent machining allowances.
3. Flaw detection and inspection
For important structural plates such as bridges and wind turbine towers, ultrasonic testing (UT) can be performed to ensure that there are no layers or large areas of inclusion defects inside. At the same time, check the mechanical properties one by one to ensure that the yield strength, tensile strength, and elongation meet the design requirements.
4、 Processing and welding suggestions
Even for medium thick plates that meet material standards, improper processing techniques can still affect the final quality of the project
Cutting method: For steel plates with a thickness exceeding 30mm, it is recommended to use CNC flame cutting or plasma cutting; Thinner sheets should be cut using laser or CNC to reduce the hardening of the heat affected zone.
Preparation of groove: Before welding, the oxide scale and oil stains on the surface of the groove need to be cleaned. It is recommended to preheat low-alloy high-strength steel and control the interlayer temperature.
Correction and stress relief: After welding is completed, vibration aging or heat aging treatment can be used to eliminate residual welding stress and prevent structural deformation.
5、 Supply and Service Description
We have a stock of medium and thick plates in various specifications, including commonly used materials such as Q235B and Q355B, and support cutting to length, non-destructive testing, and logistics distribution. We can provide the original quality assurance certificate (MTC) of the steel plant according to the engineering needs, including complete chemical analysis and mechanical performance testing reports.
Structural safety is the cornerstone of engineering construction. When purchasing, please confirm the consistency of material grades, implementation standards, and additional technical requirements based on the specific requirements of the design drawings.
