Questions raised by several experts during the defense of the drawing for unit certification renewal (answers will be rewarded)
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This post was last edited and reposted by feihong622847 on 2009-11-18 14:28. I. Saddle seat issue 1. Issue with entering the values of b and h during SW6 calculations? (This question is not about that; it’s the error I made while reviewing a colleague’s calculation sheets for their presentation.) 2. What are the principles governing the placement of saddles, and why? What are the principles for setting the fixed end? 3. How many distinct manifestation forms are there for the failure points of the saddle? 4. There are several types of equipment failures; examples for each are provided. II. Safety valve issues 1. What is the opening pressure of a safety valve? Is the pressure at which the \"puffing\" sound begins to be heard the opening pressure? 2. What is the discharge pressure of a safety valve? Describe the state of the valve disc and indicate the height it rises to 3. What is the reset pressure of a safety valve, and what is the state of the valve disc? 4. Can the opening pressure of the safety valve be higher than the design pressure (when there is only one safety valve on the equipment)? If so, under what circumstances? III. Hydrostatic test issues 1. The formula for the pressure test – what do the various symbols represent? 2. What considerations should be taken regarding the pressure value for pressure testing? (What are the principles for determining the pressure value in pressure tests, and what conditions must the stress in the cylinder meet during the test?) ) 3. Why are there specified test medium temperatures for various materials? IV. Issues related to reinforcement of openings 1. What is the scope of application of GB150-1998 regarding openings in cylinders and heads? 2. When calculating the reinforcement for openings, how is the area that needs to be reinforced determined? (What is the basis used for calculating this thickness?) 3. How should it be calculated for overall reinforcement? (What kind of stresses, etc.) V. Heat treatment issues 1. How many categories are there for heat treatment? 2. What types of equipment require heat treatment (mention general categories such as media, etc.)? 1) What thicknesses require heat treatment, and which components are used most frequently? Why? Is the heat treatment at this stage a post-weld stress-relief heat treatment, and what is it? VI. Issues with welding test plates (liquid chlorine: operating temperature –30, operating pressure 0.3 ； The designer set the design temperature at 50 degrees and the design pressure at 1.57 Mpa ； The material used is 16MnDR. 1. How should the design temperature be specified, and how should the design pressure be determined? 2. How many weld test pieces are required for low-temperature vessels? Where are they located respectively? VII. Non-destructive testing issues: What has been added to the 2005 version of non-destructive testing compared to the 1994 version? (This way of asking is related to the training we organized for those who attended the promotion event in Hainan after they returned.) I’ll ask it differently: what are the requirements for RT and UT penetration testing, and in which situations are they applicable respectively? VIII. Material Selection Issues 1. What are the principles for selecting materials resistant to hydrogen sulfide corrosion? 2. What are the requirements for materials when the hydrogen sulfide concentration is greater than 100 mg/l? 3. What issues should be considered in the thick plate design process? 4. What are the requirements for sheets in the three types of containers? 5. Should spherical tanks used in Shandong undergo low-temperature impact testing? 6. Is it sufficient to specify only GB3531 for low-temperature steel? What other requirements should be stated or what additional information should be included? IX. Basic question: What is the calculation formula for internal pressure cylinders in GB150-1998? What is its scope of application? Why?
The fixed end of the saddle should be placed on the side with more pipe openings or heavier equipment. When the equipment requires a leak-tightness test, the opening pressure of the safety valve will be greater than the design pressure. At this point, the opening pressure of the safety valve should not be greater than the maximum allowable operating pressure of the equipment. Since our final thickness is the value obtained after rounding, the maximum allowable operating pressure will be higher than the design pressure of the equipment. For equipment with airtightness requirements, if the opening pressure of the safety valve is less than or equal to the design pressure, this will cause the safety valve to open frequently during airtightness tests.
Isn’t this just testing you? I’m not in the design field, so I’m not very familiar with the first few questions. But questions 5 to 9 don’t seem too difficult; they represent the most basic concepts for anyone working in the field of pressure vessels
:Lol, it’s all about the unit conversion issues related to Viagra; we’ve discussed them several times already. If I remember correctly, it’s on his blog.
I’m sorry, I didn’t mean to mock; I was just indicating the source of the information. Moreover, the original poster should have indicated that it was reposted. 1.b is the sum of the upper width of the web plate and the thickness of the web ； The height does not include the thickness of the shims. 2. The distance from the saddle to the tangent of the head shall not exceed 0.2L (where L is the distance to the tangent of the head); if the head is to serve a reinforcing purpose, this distance shall ultimately not be greater than 0.5R ； In simple terms, the principle for choosing between a fixed end and a sliding end is to use a fixed end for pipes that are numerous and large, while using a sliding end for those that are small and few in number. 3. The area directly above the saddle is prone to flattening, so large openings should not be made there. 4. Strength, stiffness, instability, and leakage failure are the four main aspects. Stiffness and instability can even be integrated. 5. The opening pressure is the pressure at which the valve disc begins to rise; as for whether there is a hissing sound, I haven’t heard of that. In my imagination, there shouldn’t be this sound at this time. 6. Discharge pressure = Opening pressure + Overpressure portion. At this point, the valve disc is finally fully open. 7. The seating pressure is the pressure when the valve disc returns to make contact with the valve seat; the opening height is naturally 0. 8. Under normal circumstances this is not allowed, but if the maximum allowable operating pressure of the equipment is taken into account, it is permissible for the pressure to be higher than the design value.
9: The calculation formula is δ = PcDi / (2tφ – Pc), and it is applicable when K is not greater than 1.5. Heat treatment is generally divided into stress-relief heat treatment, heat treatment to improve mechanical properties, heat treatment to restore mechanical properties, and hydrogen-removal heat treatment.
LZ, even if a question is posed, an answer should be given – it’s for beginners to learn from, right?! Their answers are also incomplete.
Let me try to answer: VIII. Material selection issues 1. What are the principles for material selection in cases of hydrogen sulfide corrosion? Try to use high-quality steel with low sulfur and phosphorus content; HIC steel is the best choice. 2. What are the requirements for the material when the hydrogen sulfide concentration is greater than 100 mg/l? The materials need to be retested; it is advisable to carry out overall post-weld heat treatment. 3. What issues should be considered in the design of thick plates? Those who are not involved in design don’t know; welding thick plates is not easy, and it’s unclear whether this is related to that issue. 4. What are the requirements for steel plates for category 3 containers? The mechanical properties need to be retested on a per-unit basis. 5. Should low-temperature impact tests be conducted for the spherical tanks intended for Shandong? Referring to standard GB12337 4.2.3, steel plates for spherical tanks that meet the following conditions shall be subjected to tensile testing and Charpy (V-notch) impact testing at room temperature or low temperature, one sheet at a time: a) steel plates supplied in quenched and tempered condition; b) steel plates with a thickness greater than 60 mm. 4.2.4 For the steel plates used in spherical shells, when the design temperature of the spherical tank and the thickness of the steel plates meet the specified conditions, one steel plate from each batch shall be subjected to a Charpy (V-notch) low-temperature impact test. The test temperature is the design temperature of the spherical tank or as specified in the drawings, and the sampling direction of the specimen is horizontal. 6. Is it sufficient to specify only GB3531 for low-temperature steel? What other requirements should be stated or what additional information should be included? I really don’t know about this
H2S environment materials should be in the normalized or normalized+tempered, quenched and tempered state, and there are also requirements regarding yield strength and tensile strength; the carbon equivalent must be limited as well. Carbon steel and low-alloy steel used for shells generally require individual ultrasonic testing, as well as post-weld heat treatment. For thick plates, requirements generally include plate flaw detection, supply condition, welding flaw detection, and post-weld heat treatment. The three categories of inspections include supply condition, material re-inspection, plate ultrasonic testing, welding flaw detection (including surface inspection), and heat treatment. When it comes to Shandong, it might be related to the ambient temperature; it depends on what the ambient temperature is like there.
Is there any heat treatment that can improve surface quality? :lol