Stainless steel is essential in recent industrial production, science and technology, and daily life. There are various types of stainless steel, including corrosion-resistant stainless steel, heat-resistant stainless steel, anti-oxidation stainless steel, non-magnetic stainless steel, sterile stainless steel, precipitation-hardened stainless steel, and various economic stainless steel.
Compared with carbon steel, stainless steel has high strength, high deformation resistance, low plasticity, and other characteristics.
In the 1950s, the existing seamless steel pipe production facilities needed to meet the production efficiency and economy requirements for stainless steel pipe products. The production efficiency is very low and can not guarantee the quality of the internal and external surface, resulting in many new stainless steel materials with good use value can not be processed into steel pipes and profiles, thus limiting the use of new materials and The development of stainless steel pipe production.
Until the 20th century, the glass lubrication high-speed extrusion method was used for industrial production; most of the world’s largest companies used this method to manufacture stainless steel tubes, and the product’s internal and external surface condition was good. Therefore, the extrusion method has become the best choice for stainless steel pipe production.
Japan is one of the countries that obtained the patent right to use the “glass lubrication high-speed extrusion method” in the early days.
Currently, Japan’s use of extruded stainless steel tubes involves
- the petrochemical industry,
- chemical industry,
- petroleum refining industry,
- fiber and textile industry,
- beverage industry,
- synthetic fertilizer industry,
- thermal power generation industry, and
- the atomic energy industry.
Besides the typical stainless steel grades, there is also the manufacture of steel and alloys, such as structural alloy steel, heat-resistant chromium steel, iron-based alloys containing 5% to 30% Cr, 25-20Si stainless steel, Nemonic heat-resistant alloys, as well as molybdenum, titanium, zirconium, and other metals and alloy tubes.
After using the hot extrusion method, Japanese stainless steel tube manufacturers produce stainless steel tubes without grinding the inner surface, and the outer surface of the grinding workload is also significantly reduced.
Hot extruded stainless steel tube surface quality is very high and has good dimensional accuracy; known as the hot finishing tube in Japan, in some areas of use, especially as a piping, it can replace the cold finishing tube. The vast majority of the Japanese stainless steel pipe use sector has long recognized these advantages of hot extruded stainless steel pipe.
It is understood that the total number of extruded stainless steel tubes and hot extruded finished tubes (hot finishing tubes) used in the total number of stainless steel tubes has a large proportion of the total. For example, according to statistics, hot extruded finished tubes (hot finishing tubes) accounted for more than 67% of the market in the U.S. market for seamless stainless steel tubes. In comparison, cold-rolled cold-drawn tubes (cold finishing tubes) accounted for 33%.
In Centravis’ 4400t extruder plant in Ukraine, hot extruded finished tubes account for more than 60% of the products.
Allegheny, USA. Ludlum Steel Company, using a 1775t horizontal extruder with a central cylinder pressure of 1500t and a perforating cylinder pressure of 275t, equipped with a separate vertical perforating machine, mass production of extruded stainless steel tubes and heat-resistant steel tubes and profiles.
The thinnest wall thickness of extruded products is 2.5mm. The dimensional accuracy of extruded products reaches that of hot rolled products, where the eccentricity of steel pipes is ±10% of the average wall thickness. The straightness is kept within ±0.25mm/m. The production workshop is equipped with a 100t stretching and torsional straightening machine, and the cross-sectional area of straightened profiles reaches 3250 mm2. The products produced include 1Cr13, 1Cr18Ni9, 1Cr18Ni9Ti, Cr25Ni20Si2, and other stainless steel pipes, unequal angles, channels, and other profiles.
