Over the past 20 years, the world's stainless steel production has seen great development, process technology and equipment have greatly improved, and foreign stainless steel production is characterized by the development of new technology and new equipment to increase production, expand the variety, and the use of automatic control and nondestructive testing to improve and ensure product quality. Therefore, renovation and expansion in recent years in the stainless steel seamless pipe plant, have led way to many effective new technologies and new high efficiency equipment. 

China's stainless steel production after 40 years of development, particularly in the last 20 years, has made great progress; the yield, quality and variety continue to increase and improve the quality of products to an internationally recognized, advanced level. However, China's stainless steel tube plant technology, equipment, and product quality still have a long way to go. There is still a need for more technological innovation to improve in order to meet the requirements of our national economy. 
 
1. World stainless steel production technology trends 

2.1 "Three steps" steelmaking and continuous casting process 

The "three steps" steelmaking and continuous casting production of stainless steel tube technology improves quality, reduces costs and creates the better working conditions. Some of the world's major steel plants who continued to use the "two steps" method conducted sufficient research, and adopted the "three steps" of the new stainless steel smelting process. Most professional stainless steel plants in Japan have adopted the "three-step" production process. Germany Mannesmann Mark developed a metallurgical technology company dedicated to "three steps" of the process equipment, which includes an ultra-high power electric furnace unit, 1 MRP-L converter and a platform VOD devices. The process uses electric furnace melting, MRP-L converter plus rapid de-carbonization oxygen lance, VOD ultimate deep vacuum decarburization furnace. The basic starting point of this process is the combination of AOD and VOD processes and to develop their own advantages and overcome the AOD refractory consumption of argon gas and a large and shortcomings of the processing time to achieve low consumption, shorten time and reduce costs purposes. Of course, the furnace of AOD’s "two steps" smelting of stainless steel is also feasible, more than 60% of the steel production industry continues to use the "two steps" process of production.   

Foreign casting of stainless steel tube is vertical and curved in a continuous casting machine, but also uses a horizontal continuous casting machine. The stainless steel billet and steel ingot of a conventional rolled billet compared to the metal recovery rate increased from 10% to 15%, tube quality is better and saves energy, and reduces production costs. Some stainless steel in the continuous casting process is easily oxidized alloying elements, which makes it easy to produce oxide inclusions; In addition, the viscosity of molten steel makes it quite susceptible for nozzle clogging. As more complex forms of solidification of stainless steel, poor thermal conductivity of molten steel makes it quite easy for the billet to crack, so the cooling rate of casting requirements are more stringent.