Digging holes and tees
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Where there was originally a tee joint on the pipe, due to an oversight in material accounting and to meet the deadline, it was decided to drill a hole. What are the disadvantages of drilling such a hole?
The fillet welds formed by drilling have low strength； The welds formed between the tees and the pipes are butt welds, which possess high strength ； Tees are not allowed to be dug in high-pressure pipelines (or Class B and Class C pipelines)
Agree with the person above: handshake
“There are actually different methods for “drilling holes” as well: make a hole, insert a pipe partway in and weld it, similar to socket welding； Another method is the commonly used saddle weld; however, old pipes may suffer from reduced wall thickness, and its use should be restricted in pressure pipelines. When using this method in low-pressure pipelines, reinforcement through opening cuts is necessary. This post was last edited by johnhwa on 2008-10-12 15:40]
If there is no pressure involved and the medium is not hazardous, it should be fine; in the past, many pipe installations were carried out by simply digging holes
Agree with the person above; I’m a newcomer and I’m just learning about this issue of “digging holes”. Hehe, thanks!
Welding by drilling holes does not guarantee good weld quality, as it tends to result in slag inclusions, pores, and other defects; therefore, petrochemical industry standards generally prohibit the use of drilling-hole connections
For hole-welding, as long as the welding quality is ensured, thicker pipes can be used; strength considerations should also be taken into account. Generally, the requirements for use can be met.
It is possible to dig holes without welding; by using steel hoops, the joints that need to be connected can be welded together in advance. Once the holes in the pipeline have been dug, the steel hoops can be installed there
A fairly obvious problem is that the welding strength of the holes is poor, and this is not acceptable for pipes subjected to high pressures
This year, the maintenance materials didn’t arrive, so I dug one hole; I’ve been feeling scared all the time