ASTM AH36 steel plate heat treatment process requirements details

ASTM AH36 steel plate is a ship grade structural steel whose heat treatment process requirements are critical to ensure the desired mechanical properties and microstructure. The following are the details of the heat treatment process requirements for ASTM AH36 steel plates:

1. Normalization:
- The heating temperature is generally in the range of 890°C to 950°C.
The holding time is usually determined based on the thickness of the sheet, typically 30 minutes per inch of sheet thickness.
- Cooling method should be air cooling or forced cooling.

2. Quenching: Quenching
- The quenching temperature depends on the specific requirements and is usually cooled quickly in water or oil.
- Ensure that the temperature and speed of the quenching medium meet the specification requirements to obtain the required hardness and strength.

3. Tempering:
- The tempering temperature is generally between 590°C and 675°C.
- The holding time is based on ASTM AH36 steel plate thickness and hardness requirements, usually more than 1 hour.
- Cooling mode: air cooling or forced cooling.

4. Welding heat treatment:
- After welding, it is necessary to heat treat the welded joint to eliminate the residual stress caused by welding and improve the performance of the weld zone.
- Welding heat treatment parameters should be determined according to the specific welding method and material requirements.

5. Preheat and control cooling rate:
- For plates with thickness greater than or equal to 50mm, preheat should be carried out before welding and heat treatment, and the preheat temperature and time should meet the requirements of the specification.
- Controlled cooling rate helps to reduce deformation and avoid the formation of cracks.

6. Temperature and time control:
- Strictly control the temperature and time during the entire heat treatment process to ensure that the required mechanical properties and microstructure are achieved.
- Parameters at each stage of the heat treatment process should be precisely controlled according to specific specifications and design requirements.

These heat treatment process requirements help ensure ASTM AH36 steel plate have the required strength, toughness and corrosion resistance for applications in Marine construction and offshore engineering. In actual operation, the relevant specifications should be strictly followed, and the heat treatment process should be adjusted and optimized according to the specific situation.