Is post-weld stress relief heat treatment performed on the vinyl chloride monomer storage tank?
Thread Content
Name: Vinyl chloride monomer storage tank. Medium: Liquid vinyl chloride. Horizontal container. Design pressure: 1.6 MPa; design temperature: 80 degrees Celsius. Volume: 53 cubic meters; diameter: 2800 mm. Material: 16MnDR. 1. Is stress-relief heat treatment performed on this vinyl chloride monomer storage tank after welding? 2. Which category of container does it belong to? 3. Are the design parameters chosen appropriately?
Heat treatment helps to reduce stress in weld joints, but the additional investment depends on the wall thickness requirements
Vinyl chloride liquefied gas, moderate hazard, explosive； The first group of media belongs to Category III containers ； Post-weld heat treatment is required ； The design temperature is 80°C; why is low-temperature steel 16MnDR chosen? Q345R can be used at -20°C. Should the design temperature include the lowest design temperature as well?
The ambient temperature is -21 degrees, and the design temperature is set at -25 degrees; therefore, 16MnDR is selected. Can Q345E as specified in GB6479-2013 be used for the Takeover?
As you said, if Q345E is to be used, it is necessary to conduct low-temperature impact tests at -40°C; such design temperatures require specification of the upper and lower limits
I believe post-weld heat treatment is not necessary, as it does not comply with the requirements of clause 8.2 in GB150.
The design temperature cannot be determined solely based on the ambient temperature; it mainly depends on the temperature of the medium.