TPT May 2012

A rticle The development of AUTO- DNSA mills and ERW tube mills By Guowu Gao, chief engineer, FD Machinery, China

THE fact that the global economy is in a downturn makes investors for ERW tube mills more cautious. Only a company with sound economic strength and a stable market would consider making an investment to either build new lines or renovate the equipment, while there will be less speculative investment. Those companies have used many types of equipment that are new, old, advanced or obsolete, which enables them to accumulate useful experience in judging the quality of the equipment to help them select their favourite equipment for the future. Although the experience is useful in making a judgment it is not always enough because the technologies have been advancing continuously and people’s understanding usually lags behind the technological

development. Buyers hope to purchase cost-effective equipment with good performance and may also hope to make a useful investment while others stop investing to create an opportunity to beat competitors. However, the understanding of equipment does differ due to the different background, experience, area of the world and interest. Some companies would choose the equipment that can simply get the tube produced. Some would tend to favour equipment they have used in the past. Some with low labour cost and poor technology prefer simple equipment. Tube mill manufacturers, of course, often like their own equipment. Therefore, this paper will make an objective judgment on the equipment from a purely

technological point of view, which will be helpful for the buyers to better understand the equipment and choose the equipment that best suits their needs. The buyers of any equipment will face the issue of employees. For a production line, the technical capacity of the employees has a direct impact on the returns of an enterprise. You can often be taken by surprise by some enterprises that have built large plant buildings and installed many production lines. Only one size product is produced by each line, so this line is operated if the order is placed for this product, while other lines stop without any roller change or testing. This approach is not suitable for most tube welding plants, because not only has the profit been eaten by the plant area, but you can also never have enough production lines to match the number of products of different specifications. However, there must be some reason for such an enterprise to exist. If we ponder the reasons, we would find it is because the

DNSA mill: Horizontal stand and vertical roll stand

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M ay 2012