What should be done if the deformation of the saddle bottom plate at the sliding end of a horizontal container exceeds the required levelness?
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This post was last edited by WallaceLee on 2021-9-27 at 15:59. As shown in the image, a batch of horizontal equipment that arrived at the site suffered deformation and warping at the sliding ends as well as on the saddle base plates; these base plates did not fit properly against the foundation steel beams, with the maximum warping amount reaching 14 mm. The bottom plate of the sliding end saddle does not fit tightly against the foundation steel beam; the levelness deviation is as high as 14 mm. If calculated according to NB/T 47042-2014 \"Horizontal Vessels\", where the maximum allowable deformation deviation is ≤0.008×length of the bottom plate, it is just within acceptable limits. However, the installation company conducts inspections in accordance with the levelness tolerance requirement of 3 mm specified in HG/T 20584-2011, allowing for an additional maximum deviation of 5 mm on top of that. Requirements for deviations per NB/T 47042-2014 \"Horizontal Vessels\": Tolerance requirements for levelness per HG/T 20584-2011. Installation units have reported that the sliding end is not placed on a cement foundation created through secondary pouring, but rather on a horizontal iron steel beam foundation; it is not possible to adjust the level by using shims (as the on-site supervisor does not approve this), and it is necessary to ensure that the bottom plate of the saddle fits tightly against the foundation with a deviation of no more than 5 mm. The installation unit for the fixed-end saddle base plate has already carried out welding, fixation, and leveling on-site. The question now is: 1. As a manufacturing plant, how can the sliding end saddle base plate be leveled on-site? Within 5mm of fitting against the base? 2. As a manufacturing plant, how can we better avoid welding deformation of the saddle base plate when producing horizontal equipment on-site? What welding process should be used?
Will it vibrate? Will it have an impact on actual use? If the impact is minimal, adjustable shims can be used to level it before proceeding with the next installation steps.
The on-site installation team stated that the sliding end must fit tightly against the horizontal steel beams of the foundation; if the deviation exceeds 5 mm, the quality issue cannot be resolved, and it is not allowed to use shims to level it out. This poses a problem for our manufacturing factory.
This post was last edited by zhangjuhua on 2021-9-29 at 12:47. The ends are raised while the middle is lower – is it symmetrical? It’s already been made, but I’m not sure how to fix it. If this issue occurred before manufacturing, to avoid it one might consider: 1) welding in multiple passes with a low current; 2) measures to counter deformation; 3) fixing the ends firmly before welding; 4) changing the welding order by welding the sides first and the middle last; 5) correcting the shape after welding, or even using heat treatment, and applying external force if necessary to help it return to its original shape. In the past, bending occurred when large holes were cut in cylinders; I saw workers using a welder to heat that area from the back and then pouring water on it to cause it to contract and become straight again.
So how was this issue resolved in the end?
It’s definitely impossible to ignore it. Solution: 1. Cut off the bottom plate, trim the gusset plates and web plates, and weld them flat again. 2. Obtain a plate with a deformation opposite to that of the bottom plate, and weld it to the bottom plate. 3. Redo the fitting between the lower base and the bottom plate; however, it will need to be redone if the equipment is changed in the future.
I have dealt with similar issues: the weld was carved open, the bottom plate was heated to counteract deformation, then supported using jacks before welding. In areas where the welds were large, cladding was applied first, and care was taken during welding.
If the project documents and design drawings do not specify the bound volume standard, then it is not necessary to comply with it; the specific requirements shall be based on the design standards of the equipment. Also, the current bound edition is no longer from 2011
By the way, this kind of issue with the saddles can be adjusted through installation; both saddles certainly have some level of unevenness, so during installation it’s important to try to make the gap between the equipment saddles and the foundation even... I guess you haven’t paid enough attention to this aspect of the project – those who understand will get it
A universal installation company can’t possibly not be able to handle such a minor issue