Fillet Welding Vastly Different Steel Thicknesses

[Some Designer]

Hi All,

I'm in need of some welding advice. I have designed a bespoke access platform and I need my welders to fillet weld a 10mm thick steel rolled ring to a 45mm thick steel plate. My welders have assured me that everything be fine but I need to know that they're following a good, correct method for my own peace of mind. Any advice? They'd be MIG welding them together. I can attach photo's if it helps as they're already tacked together.

I look forward to hearing from you,

Ross.

 

[arther dailey]

surely your using qualified coded welders ?

 

[8ob]

Is the part designed in a way that makes the weld critical or non critical? Example, if the ring was merely a spacer in compression the weld would be non critical.

Bob

 

[Erie Fred]

Got a screen shot ?

 

[tigdlo]

What does the engineer that designed it to be welded say? The welded joint should be designed and inspected not left up to the welders.

 

[stuvy]

What Mig welder are they planning on using(curiosity more than anything)

 

[Some Designer]

Hi all,

Thanks for getting back to me. They're using TRIMIG 350-4S welders. I designed the joint - it's not about the size of the weld or it's design it's more I don't have experience in designing a joint with such dissimilar thicknesses and I would like some second and third opinions on the process i.e. any heat treatment etc. for my own peace of mind as this is a big platform - and yes the welder who is welding this is coded. I have attached a photo for reference (this is upside down however you can see where the fillet weld will be around the outside of the rolled ring. This is a load bearing weld.

Thanks,

Ross

 

[8ob]

I would be taking that somewhere else to get welded.

Bob

 

[Mikes]

Does the disc need to be so thick? Looks like there is a fair amount of it cut away already. If the disc was thinner then the weld would be easier. Could the disc be slotted and the cylinder 'tabbed' into it for location and strength?

 

[p0689109]

Surely if the welder is coded then he should have the answers to your query?

 

[rtcosic]

Welding Design

When designing products that require welding, the designer should consider very early on in the project the implications of the choice of welding process and how the component will be made.

www.twi-global.com

 

[tigdlo]

I designed the joint - it's not about the size of the weld or it's design it's more I don't have experience in designing a joint with such dissimilar thicknesses

So you have specified the prep, process and fillet size? How have you determined this without knowing the full process including any post weld heat treat?

and yes the welder who is welding this is coded

Coded to weld what? What is the code for welding 10mm to 45mm in a unique design? Coded welders still weld to a design drawing.

This is a load bearing weld.

Have you claculated the loads and designed the weld to hold that?

My welders have assured me that everything be fine but I need to know that they're following a good, correct method for my own peace of mind. Any advice?

You are the designer, it's all firmly on your shoulders to provide the process, if you are unsure of the complete process it shouldn't have even been tacked up. I don't know how your company is structured but there should be someone other than the welders responsible for checking the quality of the welds and that they conform to the design drawings.

If you want advice on post weld heat treat, you need to specify the material, even then it would be almost impossible for anyone on an internet forum to design your welded joint and any post weld processing, with the materials you have selected for the loads only you know, for a component only you know the specific use of.

 

[Ged93]

Sorry but it definetely sounds strange to me .. you accepted/quoted/whatever this work even knowing that you don't have enough experience to manage it ????

Also , I don't want to be unrespectful , but you are asking infos about how to do get this work done ON A FORUM ?? Really ??? Can you imagine it ? You weld this part , then it's supposed to be put in service , after some months it cracks and falls apart , someone would ask you : '' Why the hell did you weld it that way ??? '', and the aswer would be '' Because someone online told me to do so ..'' , come on !!!!!! .
What would your customer think ?? I mean , are you a pro or what ??
Phone a mechanical engineer and ask for some calculation !!! Do you really want to accept such a risk ?

Do things right , as you said , for your peace of mind .

cheers

 

[Some Designer]

I think I haven't articulated my question properly.

I'm fully qualified and have a first class masters degree in mechanical engineering. I've been doing this job for 10 years and just have never had to design a joint with vastly different thicknesses before. My platforms have been out in the field for years and they're perfectly safe. I'm not saying "I don't know how to do this and I'm just winging it" - I'm just asking for more than one source of information. Thanks for your replies anyway.

Ross

 

[TEO]

I think I haven't articulated my question properly.

I'm fully qualified and have a first class masters degree in mechanical engineering. I've been doing this job for 10 years and just have never had to design a joint with vastly different thicknesses before. My platforms have been out in the field for years and they're perfectly safe. I'm not saying "I don't know how to do this and I'm just winging it" - I'm just asking for more than one source of information. Thanks for your replies anyway.

Ross

I think it's great to ask around and seek different opinions no matter what experience you have.
Unfortunately some of the replies you've received strike a tone that's more harping than constructive and don't encourage further questions.
Without writing a novel sometimes the responses come across as curt.
Doesn't mean that some of the responses aren't bang on, just that unless you're already well known on here or any forum then you're going to have to develop a thick skin & wade through much "tone"
I like the questions at the start of the thread asking about thickness, does it need to be that thick? And tabbing.
The greater the variety of questions posted here the more we all learn..... Unless of course you're one of those forumites who knows everything.

 

[highseas]

So yeh welcome to the forum

If that was coming thru my workshop to be welded I would bevel the 10mm part, run the rosebud torch over the 45mm bit (test with a temp stick) and run a root pass as then probably 2 cover passes pretty hot and every few mins post weld I would run the rosebud over the 10mm bit to help it cool slower or cover in my old
Welding Blanket for same reason.

And I would be VERY confident in it being sound, how confident I hear theirs at the back say?

Confident enugh to put my name on it and that in this game means everything!

 

[arther dailey]

I think I haven't articulated my question properly.

I'm fully qualified and have a first class masters degree in mechanical engineering. I've been doing this job for 10 years and just have never had to design a joint with vastly different thicknesses before. My platforms have been out in the field for years and they're perfectly safe. I'm not saying "I don't know how to do this and I'm just winging it" - I'm just asking for more than one source of information. Thanks for your replies anyway.

Ross

Always good to ask , I think possibly the word designer just strikes fear in anyone who actually does hands on work, we have all had "bits" that were designed and arent actually 100% workable due to "design"
Just had a hospital bed delivered for family member , the side grab rail to assist you getting out of bed cant be used on left as the designer decided a tab to hold cables had to be put in right in the way ,there are plenty of other places it could have been put , the delivery driver who helped assemble said the air mattress for them also fail quickly because the design allows it to constantly rub..the bars to alleviate sheet weight of patients feet ...cant be used...
Strangley the nhs delivery guys face said it all when I said I could fix side bar as have a angle grinder . anyways I have done it , damned if I will have a family member fall and get injured due to faulty design.
Anyways you will get good advice on here, there are plenty of top welders and many other trades who are always willing to give good sound advice ,possibly better to run it by in the design stage pre build though I would suggest .

 

[Erie Fred]

I think I haven't articulated my question properly.

I'm fully qualified and have a first class masters degree in mechanical engineering. I've been doing this job for 10 years and just have never had to design a joint with vastly different thicknesses before. My platforms have been out in the field for years and they're perfectly safe. I'm not saying "I don't know how to do this and I'm just winging it" - I'm just asking for more than one source of information. Thanks for your replies anyway.

Ross

How doo you detail up that weld joint ?
I would assume complete penetration on the 10mm ring details, with inside and outside welds ?

BTW what is the material ? Plain vanilla Mild steel ? or something a bit alloyed ?
Yes, I would be concerned (as addressed above by HighSeas) with a rapid quench from the 45mm plate.

 

[tigdlo]

the responses come across as curt

Sorry

I think I haven't articulated my question properly.

I'm fully qualified and have a first class masters degree in mechanical engineering. I've been doing this job for 10 years and just have never had to design a joint with vastly different thicknesses before. My platforms have been out in the field for years and they're perfectly safe. I'm not saying "I don't know how to do this and I'm just winging it" - I'm just asking for more than one source of information. Thanks for your replies anyway.

Ross

It would be good if you do stick around.

To be fair, that isn't what you asked in your first post but instead asked how to make sure the welders do a proper job which has been answered.

I cant help you design your joint or weld process but have found some info in these 2 threads, maybe worth @ing a member with the knowledge and experience. https://www.mig-welding.co.uk/forum/threads/mig-welding-very-thick-steel.69711/ https://www.mig-welding.co.uk/forum/threads/2-inch-plate-fillets.96669/

 

[addjunkie]

What does the engineer that designed it to be welded say? The welded joint should be designed and inspected not left up to the welders.

A welding engineer would more likley be the person to talk too…..the welder will then get a procedure!