Welding steel tubes to chrome-moly

[minorchord2000]

I have a situation whereby I want to weld structural steel tubes to an existing chrome-moly pulverizer wheel (used at power plants to crush coal). These wheels are not required by the power plant anymore because the local power plant switched from coal to natural gas. I want to weld the ends of small tubes (2 1/2" square ASTM A500 Grade B Carbon Steel) to the chrome-moly wheel perimeter. The wheels will be laid flat. The tubes are only 1' long and will cantilever out from the chrome-moly outer perimeter and will be used to support a decorative perforated steel seat. The wheels are about 4' in diameter to the outside face and look like steel wheels (doughnut shaped).

Can it be done? If so, what kind of welding process is required? Electrodes? Preheating requirements and any post welding techniques?

Any help would be appreciated.

 

[metengr]

What is the chrome-moly composition? Is this 4130, 4140, Grade 11, 22, 5, 9?

 

[minorchord2000]

metengr:

The only other piece of information I have about these wheels is the term "gasite 20". Does that help?

 

[Mr168]

Is this going to be purely decorative or serve some sort of purpose? Those wheels aren't chrome moly, they are a chrome moly white iron alloy. Any sort of practical welding on this sort of material would be a nightmare.

 

[minorchord2000]

Thanks Mr168:

The tubes are intended to be welded to the outer rim of the wheel and will be part of a bench seat support structure. The tubes will be equally spaced at 30 degrees on center around the outer perimeter in a radial fashion. The tubes will support a live load of 100 psf or a point load of 300 lbs whichever is greater at each tube. The welding of the tube to the wheel is intended to create a suitable welded connection capable of resisting shear and moment.

From what you tell me, this idea seems improbable.

 

[Mr168]

White iron in itself is extremely difficult to weld for something that is mostly cosmetic. Factor in the high chrome content and the fact that it is mostly martensitic, and things get even more difficult.

I would look into welding plates onto the tubes and creating some sort of bolted connection rather than welded.

 

[metengr]

Agree with Mr. 168 find another way to attachment them - threaded connections perhaps?

 

[moltenmetal]

No way you can braze these on? Doesn't sound like the loading is that heavy, and braze would seem to get around the metallurgical issues associated with welding to cast (at least from a chem eng's perspective!)