Welding of overhead crane rail 2

[bakal28]

I am required to install a 2-63mm x 63mm x 100metre billet for an overhead crane rail. This is to be welded into a crane rail beam. Can someone please provide some advise on the following issues:

What are the acceptable welding procedures? I am told of 3 methods - Thermic, puddle arc and flash butt.
Is fillet weld to the beam sufficient?
Is preheating mandatory? Some say this will cause misalignments
How to weld the joints? Is cut square or bevelled acceptable?
Is weld required for the full cross sectional area of the joint?
What are the welding tests required?

This is only a 15T crane. Any quick but proper solution to accomplish this?

Thanks.

 

[metengr]

Nimajoef;
Arc welding methods are also permitted for welding to crane rails. Here is what you need to get started;

1. You must determine or know the chemical composition of the rail. There should be a material specification regarding the rail material.

2. Once this is known, you need to qualify a welding procedure using material of similar composition and heat treatment as the rail material.

3. The attached information below is a starting point regarding weld repairs of rails. This should be used for guidance in developing your own weld procedure specification.

http://www.wtia.com.au/tgn.html

4. Weld joint detail needs to be based on two factors - maximizing resistance to fatigue service and strength. You will need to evaluate the service conditions to optimize for these factors. Typically, partial penetration (bevel) welds exhibit increased fatigue resistance in comparison to fillet welds.

 

[dik]

Great link... thanks

Dik

 

[bakal28]

Metengr

Thanks for the reply.

So for any welding procedure, are we saying preheating is mandatory, even if only tucking it to set it to proper alignment? What are the chances it will misalign?

How to weld the joints? Is cut square or bevelled acceptable?

Is weld required for the full cross sectional area of the joint? -So for a 63mm square billet, what should be the size of bevel weld?

What are the welding tests required?

 

[hokie66]

You may not know, as apparently you have been directed to do this, but I wonder why a square bar is being used for a crane rail in this manner. Why not use a clamped crane rail?

 

[bakal28]

Hokie66

Its a manufacturer specs so cant do much about it. Are there any issues with square billets? What is the industry practice for a 15T overhead crane. I've only done 2 cranes and both have this for their rail.

 

[MikeHalloran]

There are at least two issues with using bar for crane rails.

1. Real crane rail's head is very hard, so wear is minimized and you don't need to use huge wheels to keep the contact stresses under the rail's yield point.

2. Real crane rail, most of it anyway, is crowned. Crowned rail interacts with tapered wheels to induce a crane bridge to guide itself into traveling straight down the runway, minimizing flange wear and noise.


That said, I have seen it done, where vertical space is at a premium, using flattish bar. I don't think I've ever seen square bar used, but I haven't seen everything yet.




Mike Halloran
Pembroke Pines, FL, USA

 

[hokie66]

Is the square bar on the crane or on the crane runway? If on a double beam overhead crane for the trolley to run on, then the welding specification should be as per the manufacturer's details. If on the crane runway beams, it is unusual for the crane manufacturer to specify the rail, and normally crane rail (like railway rails, but usually smaller) sections are used, clamped to the runway beam. Clamping allows some flexibility and also makes it practical to replace rails.

 

[corrosionman]

We did exactly this same job when we erected our 15 T in our workshop - - we just put intermittent runs of weld on either side of the 63 x 63 bar and never had any problems. The only important thing that nobody warned us was that the 63 x 63 had a heavy millscale on it and the crane was excessively noisy - we had to grind it all off to solve the problem - - It would be better to either grind or shotblast before they are erected and welded on permamently.
Good luck
Corrosionman

 

[bakal28]

corrosionman

Thanks for the reply.

Sorry Im not a welding person. Can you please advise the length and spacing of the runs and the throat size of fillet weld. Did you do any preheating? And is macro test result sufficient for the acceptance of "welding Qualification by testing"

Thanks.

 

[corrosionman]

Our runway beams were a bit on the heavy side (762 x 267 with a 20 mm top flange) Our crane runway is 100 feet long.
We worked along the full length doing a 100 mm length of "heavy fillet weld" at alternate sides of the 63 bar so that efectivly we actually had 50 feet of weld at each side of the bar. Job done without any preheating or anything special All my welder says is that he needed lots of power to get plenty heat into the bar and into the 20 mm flange.
We checked all the welds after 6 month and a couple needed re welding but been ok ever since ( 9 years ago).
Our biggest problem was to get the two bars exactly the correct spacing We built a 50 ft wide scaffold frame and carried it along the factory on a forklift to use as a spacer frame.
Best wishes
Corrosionman.