316l stainless steel seamless pipe

All metals react with oxygen in the atmosphere to form an oxide film on the surface. Unfortunately, the iron oxide that forms on plain carbon steel continues to oxidize, allowing the rust to grow and eventually form holes. Carbon steel surfaces can be secured with paint or with oxidation-resistant metals such as zinc, nickel, and chromium, but, as is known, this protection is only a thin film. If the protective layer is destroyed, the steel below will start to rust. Steel is resistant to weak corrosive media such as air, steam, water, and chemically corrosive media such as acid, alkali, and salt. Also known as stainless acid-resistant steel. In practical applications, the steel resistant to weak corrosion medium is often called stainless steel, and the steel resistant to chemical medium corrosion is called acid-resistant steel. Due to the difference in chemical composition between the two, the former is not necessarily resistant to chemical media corrosion, while the latter is generally stainless. The corrosion resistance of stainless steel depends on the alloying elements contained in the steel. Chromium is the basic element for stainless steel to obtain corrosion resistance. When the chromium content in steel reaches about 1.2%, chromium interacts with oxygen in the corrosive medium to form a thin oxide film (self-passivation film) on the surface of the steel. , can prevent further corrosion of the steel matrix. In addition to chromium, commonly used alloying elements include nickel, molybdenum, titanium, niobium, copper, nitrogen, etc., to meet the requirements for the structure and performance of stainless steel for various purposes. the

316l stainless steel seamless pipe is usually divided according to the matrix structure:
1. Ferritic stainless steel. Chromium 12% to 30%. Its corrosion resistance, toughness, and weldability increase with the increase of chromium content, and its resistance to chloride stress corrosion is better than other types of stainless steel. the
2. Austenitic stainless steel. The chromium content is greater than 18%, and it also contains about 8% nickel and a small amount of molybdenum, titanium, nitrogen, and other elements. Good overall performance, resistant to corrosion by various media. the
3. Austenitic-ferritic duplex stainless steel. It has the advantages of both austenitic and ferritic stainless steels and has superplasticity. the
4. Martensitic stainless steel. High strength, but poor plasticity and weldability. the
5. Precipitation hardening stainless steel. It has good formability and good weldability and can be used as an ultra-high-strength material in the nuclear industry, aviation, and aerospace industries. the
According to the composition, it can be divided into the Cr system (SUS400), the Cr-Ni system (SUS300), Cr-Mn-Ni (SUS200), and the precipitation hardening system (SUS600). 316l stainless steel seamless pipe detection It is a reagent for detecting Mo elements, and it will turn red when it comes into contact with Mo elements. Not very reliable though. Besides, if the Mo content is not enough, the potion cannot be detected. ASTMA321 is a stainless steel seamless pipe standard, which includes several stainless steel seamless pipe materials such as 304, 304L, 316, 316L, 317, 317L, 347, 310H, and 321H (add L for low carbon and H for high temperature) 304 domestic grades 0Cr18Ni9, 304L00Cr18Ni9, 3160Cr17Ni14Mo2, 316L00Cr17Ni14Mo2 Others can refer to the comparison table of stainless steel standard steel grades in various countries in the world. The molybdenum content in 317 stainless steel is slightly higher than that of 316 stainless steel. Due to the molybdenum in the steel, the overall performance of this steel is better than that of 310 and 304 stainless steel. Under high-temperature conditions, when the concentration of sulfuric acid is lower than 15% and higher than 85%,

316 stainless steel has a wide range of uses.
316 stainless steel also has good resistance to chloride attack, so it is usually used in marine environments. The maximum carbon content of 316L stainless steel is 0.03, which can be used in applications that cannot be annealed after welding and requires maximum corrosion resistance. The corrosion resistance is better than that of 304 stainless steel. It has good corrosion resistance in the production process of pulp and paper. Moreover, 316 stainless steel is also resistant to erosion by marine and aggressive industrial atmospheres. Heat resistance In intermittent use below 1600 degrees and continuous use below 1700 degrees, 316 stainless steel has good oxidation resistance. In the range of 800-1575 degrees, it is best not to use 316 stainless steel continuously, but when 316 stainless steel is used continuously outside this temperature range, the stainless steel has good heat resistance. The carbide precipitation resistance of 316l stainless steel seamless pipe is better than that of 316 stainless steel, and the above temperature range can be used. Heat treatment Annealed in the temperature range of 1850-2050 degrees, then rapidly annealed, then rapidly cooled. 316 stainless steel cannot be hardened by heat treatment.

Welding 316l stainless steel seamless pipe has good welding performance.
All standard welding methods can be used for welding. According to the application, 316Cb, 316L, or 309Cb stainless steel filler rods or welding rods can be used for welding. To obtain the best corrosion resistance, the welded section of 316 stainless steel needs to be annealed after welding. If 316L stainless steel is used, post-weld annealing is not required.
Typical uses are Pulp and paper equipment heat exchangers, dyeing equipment, film processing equipment, pipes, and building exteriors in coastal areas. The difference between 316L and 316 lies in the carbon content, which is difficult to measure without instruments.
316 is a type of molybdenum-containing stainless steel. Under high-temperature conditions, when the concentration of sulfuric acid is lower than 15% and higher than 85%, 316 stainless steel has a wide range of uses. 316 stainless steel also has good resistance to chloride attack. The maximum carbon content of 316L stainless steel pipe is 0.03, which can be used in applications that cannot be annealed after welding and requiring maximum corrosion resistance. The corrosion resistance is better than that of 304 stainless steel. It has good corrosion resistance in the production process of pulp and paper. performance. Moreover, 316 stainless steel is also resistant to erosion by marine and aggressive industrial atmospheres. Heat resistance In intermittent use below 1600 degrees and continuous use below 1700 degrees, 316 stainless steel has good oxidation resistance. In the range of 800-1575 degrees, it is best not to use 316 stainless steel continuously, but when 316 stainless steel is used continuously outside this temperature range, the stainless steel has good heat resistance. The carbide precipitation resistance of 316L stainless steel is better than that of 316 stainless steel, and the above temperature range can be used. The difference between cold rolling and hot rolling: Rolling at room temperature is generally understood as cold rolling. From a metallographic point of view, rolling below the crystallization temperature is cold rolling and hot rolling. ) as the raw material, after being heated, is made into strip steel by the rough rolling unit and the finishing rolling unit. The hot steel strip coming out of the last rolling mill of finishing rolling is cooled to the set temperature by laminar flow and rolled into steel strip coils by the coiler. The cooled steel strip coils undergo different finishing operations according to the different needs of users. Wire (leveling, straightening, cross-cutting or slitting, inspection, weighing, packaging and marking, etc.) is processed into steel plate, flat coil, and slitting steel strip products. Cold rolling: use hot-rolled steel coils as raw materials, pickling to remove scale, and then carry out continuous cold rolling. The finished product is hard-rolled coils. Due to the cold hardening caused by continuous cold deformation, the strength, hardness, and toughness of hard-rolled coils increase. The plastic index decreases, so the stamping performance will deteriorate, and it can only be used for parts with simple deformation. Hard-rolled coils can be used as raw materials for hot-dip galvanizing plants because hot-dip galvanizing units are equipped with annealing lines. The weight of hard-rolled coils is generally 6-13.5 tons, and the steel coils are continuously rolled at room temperature for hot-rolled pickled coils. The inner diameter is 610mm. Product features: Because it has not been annealed, its hardness is very high (HRB is greater than 90), and its machinability is extremely poor. It can only perform simple directional bending less than 90 degrees (perpendicular to the coiling direction). To put it simply, after a steel billet is heated (that is, the red hot steel block on TV), it is rolled several times, then trimmed, and corrected into a steel plate. This is called hot rolling. Cold rolling is processed and rolled based on hot-rolled coils. Generally speaking, it is a process of hot rolling---pickling---cold rolling. Cold rolling is processed from hot-rolled plates at normal temperatures. Although the steel plate will heat up due to rolling during the processing process, it is still called cold rolling. Due to the continuous cold deformation of hot rolling, the mechanical properties are relatively poor and the hardness is too high. It must be annealed to restore its mechanical properties, and it is called a hard rolled coil without annealing. Hard-rolled coils are generally used to make products that do not need to be bent or stretched. If the thickness is less than 1.0, hard-rolled coils are lucky to be bent on both sides or four sides.