welding to casting or forging???

[mikevaughn]

I currenly design a lot of weldments using square tubing and fabricated brackets. I would like to create some molded shapes to simplify the fabrication process. I know that welding cast iron is not feasable, but can you weld cast steel easily??

I am thinking of a similar material situation that you would have when making a drive shaft assembly. A tube welded to a structural shape (yoke). My question is "what is the material and manufacturing process used to make that structural shape"? Is is cast, or is it forged... or something else? Please help.

 

[DAVIDSTECKER]

If you are currently using steel such a A-36 or 1018 then you should look into castings made from ASTM A-27. It welds very well.
When you design a casting you should make your design with flowing lines and try not to design a fabrication.
Also consider that a mold is made in at least two parts and that you must allow for tapered surfaces.

 

[mikevaughn]

Here is a picture of what I am trying to accomplish. I want to weld the cast "eye" into the tube.

 

[DAVIDSTECKER]

Well the first thing I'd recommend is to go all fab or all cast.
Lets say that you have an eye on both ends. You could change the square tube to an “I” beam and blend it into the ends.
This would still work with other types of ends even if the other end is welded to another structure.
For the fab I would drill through the tube and weld in a heavy walled round tube that was chamfered on both ends to act as a weld prep, then weld on a cap if necessary.

 

[mikevaughn]

We make about 15,000 of these annually, so I am trying to reduce the amount of labor to fab the parts. We also want to use this particular bushing size because we inventory it for another use as well.

I like your first suggestion of casting it with a low carbon steel. I am in the process of quoting it now as cast steel. Tooling should be cheap too.

 

[swall]

The type of component you have presented, using a steel casting welded to a steel tube is commonplace in the off highway vehicle industry. Another possibility is to make the entire component as a ductile iron casting. I would cost out both concepts.

 

[DAVIDSTECKER]

If you are going to stay with welding the casting to square tubing I would suggest that you replace the stub that goes into the tube with a "plate" that butts up to the tube and create an area for a fillet weld. Most tubing has a weld seam on the inside that would make a tight fit hard to do.

 

[patprimmer]

Steel tubing also varies a bit in inside dimensions, so a press fit will be hard to maintain.

Cast iron can be brazed. That was a how they made bicycle frames for about 100 years or more.

Regards

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[Tmoose]

I'd be looking at A piece of thick walled tubing welded directly to the rectangular tubing, possibly finish bored after welding. I see a plug weld on the rectangular tube, suggesting you may be concerned about heavy tensile loads.

http://www.fortunecity.com/village/lind/247/weld_book/fig12-39.gif

 

[arunmrao]

I do not know if the question is still relevant. sorry for my late posting as I just happened to see it now.

Mikevaughn,you can certainly consider the complete assembly to be made from a steel casting. the grade can be ASTM A27 which can be welded easily. You have shown one end of the component. do I assume that there is another eye at the other end? The length of the component and the wall thickness of the hollow tube that you desire.Perhaps if you provide some of these I may be able to help you cast one sample piece,as I am a steel casting foundryman.

 

[dbooker630]

Depending on which grade of A27 you specify, keep an eye on the hardenability and carbon equivalent of the material. Higher strength grades in the 90-100 ksi tensile range may require large amounts of manganese, silicon, chromium or nickel to achieve mechanical properties at the expense of weldability. Keep the J4 jominy below 45HRC and the CE below .60 in your material and you'll be fine.