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Judge and explain the reason: 1. The minimum thickness of a convex head after formation in a pressure vessel should be equal to the nominal thickness minus the negative deviation of the steel plate thickness. ( ) 2. GB150-1998 provides two sets of allowable stress values for stainless steel materials; the higher allowable stress value should be used when designing cylinders, while the lower allowable stress value should be used when designing flanges and tube sheets. ( ) This post was last edited by GUANGWEI8.26 on 2009-2-18 at 14:20 ]
1. The minimum thickness of the head after molding should not be less than the nominal thickness minus the negative deviation in thickness; this is a requirement specified by the standards. However, due to issues related to the amount of thinning, manufacturers prefer not to follow this criterion. 2. Correct.
1. The minimum thickness of the convex head of a pressure vessel after forming shall be equal to the nominal thickness minus the negative deviation of the steel plate thickness. (√) 2. GB150-1998 provides two sets of allowable stress values for stainless steel materials; the higher allowable stress value should be used when designing cylinders, while the lower allowable stress value should be used when designing flanges and tube sheets. (√)
The minimum thickness of a pressure vessel’s convex head after forming should be equal to the nominal thickness minus the negative deviation of the steel plate thickness. (x) 2. GB150-1998 provides two sets of allowable stress values for stainless steel materials; the higher allowable stress value should be used when designing cylinders, while the lower allowable stress value should be used when designing flanges and tube sheets. (√)
1. The minimum thickness of the convex head of a pressure vessel after forming shall be equal to the nominal thickness minus the negative deviation of the steel plate thickness. (x) The thickness after shaping shall be not less than the nominal thickness of the component minus 2 times the negative deviation of the steel plate thickness. GB150-1998 provides two sets of allowable stress values for stainless steel materials; the higher allowable stress value should be used when designing cylinders, while the lower allowable stress value should be used when designing flanges and tube sheets. (√)
1. The minimum thickness of the convex head of a pressure vessel after forming shall be equal to the nominal thickness minus the negative deviation of the steel plate thickness. (√) This is the thickness used in the calculations for pressure vessels; as for the thinning that occurs during manufacturing, this factor must be taken into account when selecting the steel plates for production. 2. GB150-1998 provides two sets of allowable stress values for stainless steel materials; the higher allowable stress value should be used when designing cylinders, while the lower allowable stress value should be used when designing flanges and tube sheets (√)
1. Wrong. After the head is formed, its minimum thickness should be no less than the nominal thickness minus the negative deviation in thickness; as for exactly what that value is, it depends on the thickness of the steel plate used. 2. Yes.
1. The minimum thickness of the convex head of a pressure vessel after forming shall be equal to the nominal thickness minus the negative deviation of the steel plate thickness. (The answer is wrong.) The reason is: after the head is formed, its minimum thickness should be no less than the nominal thickness minus the negative tolerance for thickness reduction; as for exactly what that value is, it depends on the thickness of the steel plate used, which is why the statement is incorrect. 2. GB150-1998 provides two sets of allowable stress values for stainless steel materials; the higher allowable stress value should be used when designing cylinders, while the lower allowable stress value should be used when designing flanges and tube sheets. (right)
1. The minimum thickness of the convex head of a pressure vessel after forming shall be equal to the nominal thickness minus the negative deviation of the steel plate thickness. (x) The thickness after shaping shall be not less than the nominal thickness of the component minus 2 times the negative deviation of the steel plate thickness. GB150-1998 provides two sets of allowable stress values for stainless steel materials; the higher allowable stress value should be used when designing cylinders, while the lower allowable stress value should be used when designing flanges and tube sheets. (√)
1. The minimum thickness of the convex head of a pressure vessel after forming shall be equal to the nominal thickness minus the negative deviation of the steel plate thickness. (√) 2. GB150-1998 provides two sets of allowable stress values for stainless steel materials; the higher allowable stress value should be used when designing cylinders, while the lower allowable stress value should be used when designing flanges and tube sheets. (√)
1. Wrong 2. Correct
My answer is: 1. (Wrong) The reason is that the minimum thickness of the head after molding should be no less than the nominal thickness minus the negative tolerance for thickness reduction; as for exactly what that value is, it depends on the thickness of the steel plate used, so it is incorrect. 2. (Right)
My answer: 1. X 2. V