There is a general belief in the industry that Seamless tubes are superior in performance and life expectancy compared to ERW Pipes and majorly, welded seam of ERW tubes are considered to be the major pain point.
Today, we would like to give a small rundown of ERW and seamless boiler tubes and in the process hopefully quell some of the industry myths that have influenced your purchase decisions. Before we delve into it, we need to understand that lots of changes have happened in manufacturing of ERW pipes and tubes. Today with the advancement in manufacturing process and control technology (conditioning monitoring, on-line temperature control, on-line metallurgical control, on-line NDT it’s possible to achieve zero defect weld consistency which was not the case a few decades back. In fact Specification Bodies treat ERW and Seamless alike The defining aspect is today’s national, international recognised bodies and IBR ( Indian Boiler Regulations) suggests for the same strength level of tubes, specifies to use same chemical composition in steel, same acceptance of yield strength, ultimate tensile strength, percent elongation, hardness and flatness test for both ERW and Seamless tubes.
Designed metal temperature for MS Carbon and carbon Manganese steel) for both seamless and ERW tubes are prescribed as 454Degree C
Do ERW tubes corrode easily?
Another common allegation is ERW tubes corrode easily at the weld, but the fact is that if no external electrodes are used, it wipes away any possibility of differential corrosion.
Today, ERW tubes are normalized in the final stages to achieve homogenized microstructure to rule out any possibility of corrosion due to microstructure in homogeneity.
Surface Defect Advantage
Seamless tubes are characterized with surface defects of varying length in the inner surface whereas ERW tubes, with the advent of modern manufacturing processes , today ERW tubes has less surface defects both in the inner and outer surface compared to Seamless tubes Thickness Variation comparison between Seamless & ERW Seamless tubes are generally characterized by large thickness variation whereas ERW tubes are produced with closer thickness variation and hence the heat transfer may not be uniform in the seamless tube. The allowed thickness variation in seamless tubes is as high as 35%, whereas in ERW tubes it’s comparatively lower. For the same nominal thickness and OD, the pressure ratings points are lower for Seamless tubes compared to ERW tubes.
Also, most importantly for the same nominal thickness and tonnage more length of ERW tubes can be produced.
As you know ERW tubes are affordable and also available in greater lengths in the rack compared to boiler tubes, it’s only sensible to choose modern ERW tubes compared to seamless tubes. All you need is to compare against some of the best ERW tube manufacturer brands in the market and find
their authorized dealer and supplier.
Though Seamless tubes have their own share of advantages and can hold fort in specific situations it’s time we wake up to the latest changes in the steel pipe and tube industry and hope with this note, we would have helped you to overcome some myths.
About Madras Steels:
From the humble beginnings back in the year 1988, Madras Steels & Tubes has reinvented the idea of traditional Pipe & Tube suppliers in India delivering standard and customized piping and tubing solutions in Galvanized steel, mild steel, stainless steel, Seamless, ERW/SAW, Boiler Tubes, CRCA Round tubes etc.,
We are a leading exporter/ importer/ authorized dealer for tubes and pipes with branches in cities like Chennai, Mumbai, Bangalore, Kochi, Hyderabad, Visakhapatnam, Ahmedabad, and Delhi.