How are the bolts put into the flange holes?
Insert the bolts into the flange holes and start by pulling up all bolts finger tight. Then in the order shown, pull-up the bolts to half torque, again in the order shown, pull-up the bolts to the final torque, finally go back over all the bolts, in the order shown, and re-torque them again to the final torque to confirm all are correct.
What kind of bolts do you use for piping?
They can be either fully threaded or partially threaded. As per ASME B16.5, one can use either square head machine bolts or studs for making a joint. Also, studs are preferred over bolts due to ease of insertion during assembly.
When do you tighten a bolt do you use a spring?
The effects of thread surface finish on friction. Proper bolting practices, sequence, and methods. A bolt is not a bolt – it is a spring! When tightening a bolt you are tensioning or slackening a spring. The sketches In Figure No. 1 show how a spring can be considered to replace the bolt pulling the flanges together. Figure No. 1.
How much torque do you need to tighten a 20 mm flange?
The assembly torque that is recommended for high tensile 20- mm bolts to give 75% yield stress is about 550 Nm. A man tightening a 20-mm diameter flange bolt with a 300-mm, or even a 450-mm, long spanner would probably not generate enough force to tension the bolts.
How is hot bolting used in pressure pipelines?
It is carried out one bolt at a time in a predetermined cross pattern sequence. Each bolt is fully tensioned before the next one is removed. Hot bolting can be used to clean, lubricate, and reinstall existing bolts for pre-shutdown activities, replace corroded or damaged bolts, or upgrade the material specification or grade of bolts.
When to replace studs on pressure pipeline flanges?
It is common for us to replace studs on flanges that are in-service. We only allow this on flanges with 8 or more studs. For “high risk” streams, we require special review and approval. We define high risk streams as: above auto-ignition, high pressure (above 500 psi), toxic (such as high H2S above IDLH), and vapor cloud potential.
What do you need to know about hot bolting?
For what its worth, the definition is: Hot bolting is the sequential removal and replacement of bolts on flanged joints while under reduced operating pressure. It is carried out one bolt at a time in a predetermined cross pattern sequence. Each bolt is fully tensioned before the next one is removed.
Where can I find metric spring bolts on Amazon?
After some research, I found the exact size of the metric spring bolts I needed and found them on Amazon as Dorman 675-221. These were a few bucks cheaper, much heavier, and were an exact match for the old bolts in dimension, design and thread..