Selection of material for the tower skirt base
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This post was last edited by hetichang on 2011-5-11 23:23. How should the material for the skirt cylinder of a tower be selected? According to the technical specifications for tower equipment, if the design temperature is below 0 degrees Celsius, Q235-B cannot be used. If there is no insulation material and the lowest operating temperature is below 0 degrees Celsius, can Q235-B still be used? The operating temperature of the equipment is 50 degrees Celsius. Please explain whether the design temperature of the skirt base is related to the operating temperature of the equipment
It mainly depends on the standards you adopt; according to HG20652, Q235-B cannot be used below 0 degrees, while SH 3098 does not impose any such restrictions. When the design temperature of the tower is below 350 degrees, the design temperature of the skirt is generally taken as the ambient temperature; when the design temperature of the tower is 350 degrees or higher, an air separation box should be installed at the top of the skirt.
JB4710 6.2.2 states that it should be selected based on the compressed element. However, I saw in one of Wang Fei’s books on questions and answers (a reference book) that it is not necessary to select components based on their resistance to compression; but in order to show emphasis on the selection of the cylinder used for the skirt, a low-temperature impact test can be conducted as an alternative to using low-temperature materials. Regarding the technical specifications for tower vessels, if the design temperature for the tower I’m designing is set at -12 degrees Celsius, isn’t it not appropriate to use Q235B? I’ve changed it to Q345R already, but some people here say that Q235B seems to be acceptable as well. Could someone give me a definite answer? Thank you
It is not acceptable to use Q235-B; Q235-C can be used with additional requirements for impact testing. Using Q345R would be somewhat wasteful.
Well, I thought the same thing. But it seems that Q235-C isn’t commonly used, and the price difference isn’t that significant either. So I decided to go with Q345R. Hehe
Use Q345R; it doesn’t require much material either, saving trouble
For JB4710 5.1.2.d, the design temperature for the skirt housing and foundation bolts shall be the minimum value of the monthly average lowest temperatures in the area of use, plus 20°C. We’ll decide on the material after checking your actual temperature
It’s better to use Q345R; it won’t cost much more, and the weight of the skirt base is not that significant either
It’s embarrassing to see LZ being so careful with costs. It seems that in the equipment I’ve designed, the skirt sleeve sections are made of Q345R, while the foundation bolts are made of Q345 series materials; however, this is also specified by the project requirements. Insulation rings are used when temperatures are high, and transition sections are employed when different materials are used compared to those of the tower body.