Learning, Books, etc 1

[Beggar]

As part of my BSME, I took a welding survey course but it we just learned the very basics of stick/TIG/MIG along with a dose of oxyacetylene tossed in.

I've several times been through the welding sections in Shigley's machine-design text and his machine-design handbook.

I've also read sections of the two Blodgett books through Lincoln.

My problem is, I still don't really know how to detail the fabrication of a weld. For example, we build large machine bases for our equipment. While I can analyze the welds for strength and fatigue, I was just reviewing a drawing created by my predecessor where it calls out a pre-heat requirement, the minimum number of passes, and a requirement to place a 1/32 spacer between two places being joined by fillet welding. I cannot find any reference by which I can validate that drawing so I'm just following it blindly which is pretty scary to me.

My question, then, is what references am I missing? I've glanced at the AWS site but was overwhelmed by the number of different spec's available. I suppose if I could preview them I'd have some confidence in whether they provided the necessary info.

What recommendations would y'all have that would help me to "get smart?" I'm not looking to become a welding engineer but I do need to learn more than I know. I'm just not sure how.

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Bring back the HP-15

http://www.hp15c.org

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[metengr]

For starters, I would probably obtain a copy of AWS D1.1 Structural Welding Code - Steel. For the type of work you perform, this Code would be suitable to provide guidance for weld joint detail, qualification of welding procedures/welders, preheat maintenance, inspection and other information.

 

[Heckler]

Here is some data:

AWS (American Welding Society)

http://www.aws.org

http://global.ihs.com/search_res.cf...NGL&input_doc_title=weld symbols&org_code=AWS

ANSI/AWS A3.0, Welding Terms and Definitions, Including Terms for Brazing, Soldering, Thermal Spraying, and Thermal Cutting

http://www.welding.org/cart/training/awsbooks.htm

 

[Goahead]

I would like to suggest that basic information on welding is best explained and presented in available Handbooks like AWS Welding Handbook 9th edition vol. 1 & 2 (three more are due to be published in the future).

Also ASM International Handbook Vol. 6 (published 1993).

ASM Metals Handbook 8th Ed. Vol. 6 (published 1971) is a different book altogether, still very useful, rich of examples that help understand the reasoning behind improvements in processes.

http://www.welding-advisers.com/

 

[arto]

Also:
ASME B&PV Code Section IX
MIL-STD 22D
MIL-STD-278F [not current-replaced by S9074-AR-GIB-010/278]
& more books from Lincoln:

https://ssl.lincolnelectric.com/foundation/

for referencr, ASME Sec. VIII gives preheats for various materials (i.e., Table UCS-56)

 

[MadMango]

I found the following site very helpful in explaining the meaning and application of weld symobls on drawings.

http://www.unified-eng.com/scitech/weld/weld.html

[green]"I think there is a world market for maybe five computers."[/green]
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Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[pipewelder1999]

The books by Blodgett probably address the use of spacers for reducing residual stress resulting from weld contraction upon cooling. This allows the shrinkage forces to deform the spacers upon contraction and thus reducing residual stress.

By controlling the minimum number of passes, the heat input may be easier to control.

Preheat will also reduce residual stress provided it is applied properly.

The less residual stress, the more dimensionally stable the weldment will be . This can be more noticable on items which get subsequent machining.

Hope this helps

Gerald Austin
Iuka, Mississippi

http://www.weldinginspectionsvcs.com

 

[Rjeffery]

When designing a weldment it is best to contact (pick the brain of) a welder as they will have to weld the parts together.

 

[BillPSU]

Designing the components of a weldment and the weldment starts with an understanding of your proposed welding process and its requirements. There is a great deal of difference in robotic welding and hand welding. Robotic welding improves with repetitive weld seam locations. Parts typically need to be straighter and flatter than if you hand weld. Gaps can easily be filled with a human welder while a robot cannot. Will your fixture for assembling the parts hold the parts well enough to finish weld in the fixture or is this a tacking fixture only. Do you build gap into the parts for welding or are the parts designed to self fixture by butting into another part. Does the welding process need a gap. An example would be a cylinder welded by submerged arc, the part I made was designed with a 1/16" gap for a full penetration weld.

You need to talk with the manufacturing engineer at your facility if you have such a person and dicuss the process that will be used to make the weldment. Talk about the ability to assemble and then weld the parts and how the parts are located. You should then have a better understanding on how to design your components and the welding of the components.

 

[Beggar]

You need to talk with the manufacturing engineer at your facility ...

Therein lies the problem: Our whole company has five folks, top to bottom. I've never worked with a welding engineer or MfgE with expertise in metal joining so I've never had the opportunity to pick those brains...

--------------------
Bring back the HP-15

http://www.hp15c.org

--------------------

 

[BillPSU]

You need to become your own manufacturing engineer and do the best you can. You will make mistakes and learn the hard way as all the other manufacturing engineers have done or hire yourself a consultant or hire yourself a manufacturing engineer.

P.S. I'm looking for work right now.

 

[ledon]

I know the feeling. I am the weld progrm manager and NDT III for a small engineering company. Weld design and process seem to be little understood items in smaller firms. If I can help....

lwatkins@delphinus.com