The welded steel pipe has won praises for its uniform wall thickness and low price. So, can seamless Steel Pipes be replaced by welded steel pipes? The answer: NO
There are some reasons
1) HAZ is very fragile
Although it is rare now that the mechanical properties of the weld seam exceed the base metal itself, the weakest part of the welded steel pipe is not the weld seam, not the base metal, but the heat-affected zone of the weld. This place is the most vulnerable.
2)The limited upper wall thickness of the welded steel pipe
Most thick-walled steel pipes can only be seamless steel pipes instead of Welded Pipes
3)The H2S resistance of welded pipes is far worse than that of seamless pipes.
The requirements for seamless pipes on NACE MR0175 are: the S content must not exceed 0.010%. However, the requirements for Steel Plates and welded pipes are particularly strict: S must not exceed 0.003%. Although strict requirements are imposed on the steel plate, it can pass the HIC test, but the welding seam has to pass the test, which is still a very difficult problem. Not only must we choose the good welding material, but also the skilled welding process.
Oftentimes, using stainless steel components seems like a simple solution to corrosion on Steel Coils. You may see fins or tubes or other parts of the system show signs of corrosion, and it seems that the best option is to change the coil to stainless steel, solving the corrosion problem permanently. While this seems like a simple solution to a significant problem in the HVAC, industrial, and commercial systems where coils are found, the answer to the question “should I make an all-stainless coil?” is far more complex.
To better understand the potential impact of using an all stainless steel heat exchanger, let us evaluate an example 400,000 BTU/HR (33 tons or 119 kW) cooling coil. For the example, we will use 45° F water and a 36” x 45” coil with standard copper tubes and aluminum fins. The coil for this installation will be 12” deep, weigh 320 pounds and have a cost factor of 1.0. This is our base unit and is the component currently installed in the system.
Drilling or workover rigs, iconic symbols of the oil field, are not always required for drilling, completions or maintenance operations. Increasingly, the Oil Tubings unit is used for many good intervention operations and certain drilling applications. Coiled tubing (CT) refers to a continuous length of small-diameter steel pipe and related surface equipment as well as associated drilling, completion and workover, or remediation, techniques. Coiled tubing oilfield technology was initially developed for working on live, producing wells. More recently, this technology has gained wider acceptance among operators for an expanding range of workover and drilling applications and for its ability to reduce overall costs. The trend toward extended-reach wells favors CT for its capability to drill or to convey tools and equipment in high-angle wellbores.