The application of stainless steel pipe in the automobile industry is developing rapidly. In recent ten years, stainless steel pipe materials have been widely used in public transportation tools such as buses, subways, high-speed railway vehicles, household cars and so on!
5 identification number and indication use international chemical element symbols and national symbols to indicate chemical composition. For a long time, stainless steel plate, stainless steel coil, stainless steel belt and stainless steel pipe have complete products, excellent quality and favorable price. Use letters to indicate composition content: for example, China and Russia use fixed digits to indicate steel series or numbers; for example, the United States Japan, 300 series, 400 series 200 series; the serial number is composed of Latin letters and order, which only indicates the purpose.
.Model 303 & mdash; Add a small amount of sulfur and phosphorus to make it easier to cut.
The heat-treated alloy should be 1900 DEG at low temperature; Annealing treatment at the temperature of F, then rapid cooling and water quenching. This treatment is applied to solid melt annealing and stress relief. Stress relief treatment, such as below 1900 DEG; F, which is easy to lead to the precipitation of harmful metal or non-metallic phases.
.The inner and outer surfaces of precision stainless steel pipe and thick wall pipe shall be free of cracks, folds, cracks, rolling folds, delamination, which need to be completely removed (unless they are specially used for machining) And after removing the stainless steel pipe wall, the wall thickness and outer diameter shall not exceed the negative deviation. As long as some minor surface defects that do not exceed the allowable negative deviation do not need to be removed.
According to the purpose, it is mainly divided into oil well pipe (casing, oil pipe and drill pipe), pipeline pipe, boiler pipe, mechanical structure pipe, hydraulic prop pipe, gas cylinder pipe, geological pipe, chemical pipe (high-pressure fertilizer pipe, petroleum cracking pipe) and marine pipe. Calculation formula for weight of stainless steel square tube: (nozzle perimeter 14 - actual thickness) actual thickness is 0.02491, of which 0.02491 is a constant converted from stainless steel density.
. The agitation in the futures market is more direct. If there is an abnormal change in inventory, whether it increases or decreases, it will become a speculative type of mall participants.
For the length of welding arc, 2 ~ 4mm is better for ordinary steel welding, and ~ 3mm is better for stainless steel welding. If it is too long, the protection effect is not good.
Duplex stainless steel product description: This stainless steel has good corrosion resistance in urea carbamate solution and high stress corrosion cracking resistance in chloride environment. At the same time, the duplex stainless steel has excellent mechanical properties and can be used in plant construction with high safety requirements.
2. Raw material problem of stainless steel pipe. If the hardness is too low, it is not easy to polish (BQ is not good). If the hardness is too low, orange peel is easy to appear on the surface during deep drawing, which affects BQ performance. BQ with high hardness is relatively good.
Executive standard.It has excellent stress corrosion cracking resistance. Even duplex stainless steel with low alloy content has higher stress corrosion cracking resistance than austenitic stainless steel, especially in the environment containing chloride ions. Stress corrosion is a prominent problem that ordinary austenitic stainless steel is difficult to solve.
410— Martensite (high strength chromium steel), good wear resistance and poor corrosion resistance.
. The agitation in the futures market is more direct. If there is an abnormal change in inventory, whether it increases or decreases, it will become a speculative type of mall participants.
The resistance linear coefficient, thermal conductivity, quality hot melt and magnetism of stainless steel pipe will change greatly at low temperature. Resistance, line coefficient decreases at low temperature; The thermal conductivity and mass heat capacity decrease sharply at low temperature; Young's modulus (longitudinal modulus) increases when the temperature decreases. Because the austenitic series stainless steel pipe has MS point (martensite start temperature or martensite formation temperature) at low temperature (subzreo temperature), martensite can be formed when it is kept below MS point. The formation of martensite at low temperature makes the representative steel sus (18Cr-8Ni) of austenitic stainless steel non-magnetic at room temperature and magnetic at low temperature.
Safety and health.The inner and outer surfaces of precision stainless steel pipe and thick wall pipe shall be free of cracks, folds, crazing, cracks, rolling folds, delamination, scabs and other defects which need to be completely removed (unless they are specially used for machining) And after removing the stainless steel pipe wall, the wall thickness and outer diameter shall not exceed the negative deviation. As long as some minor surface defects that do not exceed the allowable negative deviation do not need to be removed.
The welding of stainless steel pipe is usually composed of backing welding, filling welding and cover welding. Backing welding of stainless steel pipe is a key link in stainless steel pipe welding, which is not only related to the quality of engineering
Check the clamping forming effect after each clamping, and there shall be no clamping in place or serious depression of pipe clamping. According to visual inspection, ranging from 0.1-2mm. The larger the pipe diameter the greater the difference.
.Carbon structure delivery status: delivered in heat treatment (annealing, normalizing, tempering after normalizing, high temperature tempering).
Hot rolled belt, stainless steel etching belt, stainless steel stretching belt, stainless steel polishing belt, stainless steel soft belt, stainless steel hard belt, stainless steel medium hard belt, etc.
Stainless steel pipe will rust? Stainless steel pipe is a food grade stainless steel pipe recognized by the state. It is not absolutely non rusting, but it is not easy to rust compared with other steel grades. Many people will think that the stainless steel pipe is not rusty, which is more difficult to rust. If it is rusty, they will doubt whether it is fake, whether it will be replaced by 201 stainless steel pipe, or there is a problem with the raw materials of the steel strip. In fact, these questions and judgments are one-sided views on the lack of understanding of stainless steel pipes. Stainless steel pipes may also produce rust and rust spots under certain conditions.