Repair of damaged steel structure 2

[engtiuser2]

I am looking for reference to help creating a guideline for assessing the damaged steel member and develop criteria for cold straightening. The steels (mild steel) are typical in the sheet and bar form and damages by bending. I am looking for a best practice/industrial standard/ rule of thumb to determine if the damage can be repaired by cold straightening. Example of criteria includes radius of curvature of the bent, the stain of the deformation and stress over yield strength etc.

Thanks,

L.

 

[robyengIT]

in french : "Réparation et rénovation des structures métalliques"

https://www.eng-tips.com/viewthread.cfm?qid=476563

 

[CWB1]

What you need from us? Do the research and calculation for your project? If you don't know how to do it yourself, pay someone that knows how.

Sounds like they are writing a corporate standard to save engineering involvement in common rework, not just reworking one part or assembly. Starting with a sample doc is always a good idea to prevent missing details. Not sure of the OP’s niche, but I would contact the applicable trades organizations with this question. Beyond that, boundary diagrams and feedback from both engineering and the trades are your best friends.

 

[engtiuser2]

I am looking for a simple guideline to help the production to determine whether a damaged part can be straightened. There are publication mentioned 5 percent permanent strain should not tolerable for any damage but the rationale can never be found. If 5% limit is true, I can come up with certain measurable criteria to have the QC measure and disposition the part.

 

[mfgenggear]

"I am looking for reference to help creating a guideline for assessing the damaged steel member and develop criteria for cold straightening. The steels (mild steel) are typical in the sheet and bar form and damages by bending. I am looking for a best practice/industrial standard/ rule of thumb to determine if the damage can be repaired by cold straightening. Example of criteria includes radius of curvature of the bent, the stain of the deformation and stress over yield strength etc."

what type of damage to the steel, is it cracked, yielded, ? is there NDT involved. re heat treating to obtain the original physical metallurgical properties.

 

[drawoh]

engtiuser2,

You are not telling us enough. How did it get damaged? Does the repaired part have to look good? Is it safety critical?

--
JHG

 

[r13]

Here is something basic regarding metal straightening. Link

 

[engtiuser2]

The bar or pipe is typically failed by overloading by cantilever action (one end fixed while other end support a load). It typically bent the shaft in curve shape. The steel is made out of of AISI1030. There is typically yielding but no cracks. The parts are zinc plated and we do not want to re-coat, hence, the method is restricted to cold straightening. The straightening should not cause stress raiser or change the cross section shape (to maintain the load carrying capacity). Some surface scratch is permissible. We have no resource to make this an scientific project to analysis each damaged bar for the fatigue damage. We are looking for a practical guideline set up the criteria to repair or replace the part.

 

[engtiuser2]

Thanks R13, the article also mentioned 5% strain, but again, there is no reference to any specification.

 

[r13]

engtiuser2,

I think it was done by testing. You might need go down to that route too.

 

[robyengIT]

You can have a look to :"AWS D1.7/D1.7M : 2010 - Guide for strengthening and repairing existing structures"