Maintenance on heavy machinery requires following proper practices and procedures to implement repairs to equipment. Often times maintenance turns to welding over the top of the crack—which is comparable to throwing a Band-Aid on a deep cut that actually needs stitches: it’s not a sustainable, long-term fix. Therefore, General Kinematics wants to help teach the proper procedure for repairing a crack on a vibratory piece of equipment.
Here are the central step-by-step points for how to repair a crack while also ensuring welding best practices.
Welding Best Practices
The first step to take in this process is troubleshooting possible causes that have lead to a crack. Check for possible upset conditions or buildup of material that has caused an over stroke condition on your machine. Once that is identified, implementing the proper techniques and solutions to solve this issue is key. After that is completed repair of the crack may begin.
For starters, a crack cannot be fixed by just filling it in.
“You need to properly prepare the welds and remove the crack,” said Joel Jacobson, Director of Manufacturing at General Kinematics, pointing to an example of customer’s attempt to fix a piece of steel.
“When a customer welds over the top of the crack, you can see from the cross-section view that the crack is still there.”
Here’s the proper procedure for repairing a crack:
- First, locate the end of the crack. You may need to add extra heat with a torch in order to do so.
- Sand down the area.
- Once you’ve located the end of the crack, drill a hole at its end. That hole is often a quarter of an inch in diameter, depending on the thickness of the material.
- Then, using an air arc or a grinder, grind out the whole length of the crack to prepare the area that you are going to weld.
- Now, onto the welding portion: Weld up one side of the grooved out crack. You may use the 70S-6 Carbon Steel Welding Wire or a 782 Stick Electrode. Note: do not weld up the hole that you drilled at the beginning of the session.
- Next, grind down the weld to prepare the metal for the fishplate that will be installed.
- To install the fishplate, carefully tack the starts and stops of the welds that you are going to put in. Remember: you do not want to weld over the freshly prepared crack. Place your tacks three-quarters of an inch to one inch on each side of the crack.
Also, do not weld at the end of the fishplate, as this will cause an abrupt change in the cross section of the steel and will not allow the forces to travel down the length of the machine as intended.
There you have it, crack repair complete!
Using welding best practices are important for both the longevity and functionality of your vibratory machinery.
If you have any questions, please contact General Kinematics customer service. We are happy to help.