Non Destructive Testing on ride welds

[Anything]

When welds are found to have cracked in service, what is the repair procedure? Is the car/support/whatever replaced, or is the crack ground out and re-welded?

 

NDT is basically (some of) the testing they will do on rides during the closed-season.

[Chroniq]

Although I have absolutely no experience in NDT or welding, I believe the answer is that they ship the item back to the manufacturer (or send a team to the site) and the manufacturer either rewelds to spec or replaces the item.

 

This is done for two reasons. 1- Insurance- Major theme parks must operate a ride with verification of safety and quality from the manufacturer. 2. Liability-Most theme parks don't have maintenance staff that are able to weld to manufacturer specs.

 

 

For older rides or fly by night operators, I'm sure they just re-weld and cross their fingers.

[Mechanic]

Quoted from the following link: www.weldingandgasestoday.org

 

America’s Roller Coast

Nestled in the northeast corner of Ohio, in the town of Sandusky, is Cedar Point, an amusement park that is appropriately nicknamed “America’s Roller Coast.” The park features 17 of the world’s finest steel roller coasters and, as you might expect, that means a lot of welding has to happen. “Man, we do a lot of welding around here,” says Eric Lapp, ride maintenance supervisor at Cedar Point. “Every coaster is either made of steel or has a steel track, which means they require constant welding maintenance.” To keep up with the demand, the park employs two full-time welders who are responsible for managing any breaks or cracks on a ride’s track. Cedar Point also has an on-site technician who inspects the structural integrity of the steel rides on a regular basis, looking for any cracked joints or broken seams.

For those of you who want to see a large scale example of what our industry is capable of, look no further than the park’s 420-foot-tall Top Thrill Dragster (TTD). The TTD is an accelerator coaster that generates its power from a hydraulic launch system. The TTD starts its journey with a burst of speed, generated by compressed nitrogen, which is strong enough to carry the train up a 400-foot vertical incline at speeds approaching 120 miles per hour. The coaster is powered by four nitrogen-backed accumulators, each of which holds up to 70 gallons of oil. The nitrogen pressurizes the oil to 320 bar. Upon takeoff, the pressure is discharged simultaneously from all four accumulators, resulting in a force of 10,000 horsepower. It’s an incredible spectacle and a testament to the power of compressed nitrogen. And as it should happen, the TTD’s local nitrogen supplier is GAWDA member O.E. Meyer Company of Sandusky, Ohio.

 

No matter where you go across this great nation, there are numerous sights to behold and it takes the combined efforts of American Industry to make many of them possible. While it might not be the foundation that these destinations were built on, the gases and welding industry is certainly what holds many of them together.

 

It's my understanding that several different methods of non destructive testing can be, and are, performed on ride vehicles and tracks. They would include: Visual inspection (VT), magnetic particle inspection (MT, or magnaflux), radiographic inspection (RT, or x-ray), liquid penetrant inspection (PT) and ultrasonic inspection (UT).

 

While I'm certainly not an expert on the subject of roller coasters specifically, I am an automotive technology instructor with over 25 years of field experience, as well as a hobby machinist and welder. I have considerably more training and experience in the area of metallurgy, welding, and testing than your average person.

[Anything]

Thanks guys. I do NDT as part of my job, but I have never worked on rides.