In engineering, the following methods are often used to prevent intergranular corrosion: reduce the amount of carbon in steel so that the amount of carbon in steel is lower than the saturated solubility of austenite in equilibrium, that is, fundamentally solve the problem of precipitation of chromium carbide (crc) on the grain boundary. Generally,BrindisiStainless steel seamless pipe, the requirement of intergranular corrosion resistance can be met when the amount of carbon in steel is reduced to less than .%.This kind of steel pipe can be divided into stainless steel seamless steel pipe and stainless steel welded steel pipe (slotted pipe). According to different manufacturing processes, it can be divided into several basic types: hot rolling, cold drawing and cold rolling. According to the section shape, it can be divided into circular pipe and special-shaped pipe. Circular steel pipe is widely used, but there are also some square, rectangular, semicircular, hexagonal, equilateral triangle Octagonal and other special-shaped stainless steel pipes.At low temperature ferritic stainless steel pipe has low-temperature brittleness like carbon steel, ferritic or martensitic stainless steel produces low-temperature brittleness but austenitic steel does not. Therefore, while austenitic stainless steel or nickel base alloy does not show low-temperature brittleness. Sus (Cr) and SUS (cr) of ferritic stainless steel pipe It shows that the impact value decreases sharply at low temperature. Therefore, it is necessary to pay special attention when using at low temperature. As a way to improve the impact toughness of ferritic series stainless steel high purification process can be considered. With the help of C and N level, the embrittlement temperature is in the range of - ℃ to - ℃Variable cost,High frequency welding high frequency welding: with relatively high power supply, it can reach a higher welding speed for steel pipes with different materials outer diameter and wall thickness. Compared with argon arc welding, it is more than ten times its high welding speed. Therefore, stainless steel pipes for common use have a higher consumption rate. Due to the high speed of high frequency welding, it is difficult to remove burrs in welded pipes. At present, high frequency welding Welded stainless steel pipe can not be borne by chemical and nuclear industries, which is also one of the reasons.Stainless steel, precipitation hardening stainless steel and high alloy with iron content less than % are usually named by patent name or trademark.The American Iron and Steel Institute uses three digits to identify various standard grades of malleable stainless steel. Among them, austenitic stainless steel is marked with numbers of and series. For example, some ordinary austenitic stainless steel is marked with and.
Water preparation, storage, transportation, purification, regeneration, seawater desalination and other water industry excellent materials. The demand is about tons.Range,Raw materials -- strip splitting -- welded pipe making -- heat treatment -- Correction -- straightening -- end repair -- pickling -- Hydrostatic Test -- Inspection (spray printing) - packaging -- delivery (warehousing) (pipes for welded pipe industrial piping).Hot rolled silicon steel sheet hot rolled silicon steel sheet is represented by Dr, which is divided into low silicon steel (silicon content & le; %) and high silicon steel (silicon content & amp; gt; %).The slab solidified on the surface continues to be rapidly cooled through the secondary cooling section until the core becomes solid, and the whole continuous casting process of stainless steel pipe fittings is completed.Brindisi,Shape, stress,BrindisiStainless steel sanitary pipe, temperature and metal flow of forgings and dies. Results the multi-step upsetting extrusion process under high temperature can make the end of steel pipe meet the forming requirements. Conclusion the plastic forming process of steel pipe end is feasible, which has important reference significance for the improvement of pipe connection mode of railway freight car braking system.The shape of pipe end stainless steel pipe can be divided into smooth pipe and threaded pipe (threaded steel pipe) according to the state of pipe end. Threading pipe can also be divided into ordinary threading pipe (pipe for conveying low pressure such as water and gas, which is connected by ordinary cylindrical or conical pipe thread) and special threaded pipe (pipe for petroleum and geological drilling, which is connected by special thread for important threading pipe). For some special pipes, in order to make up for the impact of thread on the strength of pipe end, the pipe end is usually thickened before threading (inner thickening, outer thickening or inner and outer thickening).Corrosion resistance of decorative stainless steel pipe the price of different series of stainless steel materials varies greatly. The corrosion resistance of more economical materials can not meet the higher application requirements, and the improvement of corrosion resistance of stainless steel materials by simple chemical passivation is limited. On the other hand, the traditional passivation treatment containing chromium salt has been gradually eliminated, and the passivation treatment of stainless steel has turned to the direction of environmental friendliness. Recently, citric acid passivation and silicon treatment on stainless steel surface have become a new research direction. The former has environmental protection characteristics because its passivation solution component does not contain chromium salt. The latter has found that silicon coupling agent is chemically adsorbed on the metal surface to form a protective silicon film with cross-linked network structure. The length of discoloration time of samples after different surface treatments was compared by blue dot method, the corrosion rate of samples after different surface treatments was distinguished by brine immersion test, and the salt spray resistance of samples after different surface treatments was distinguished by neutral salt spray test, The differences of pitting corrosion resistance and resistance to corrosive medium of samples after different surface treatment were compared by electrochemical test. The film thickness of silicon film was indirectly characterized by film weight test, and scanning electron microscope, energy spectrometer, X-ray diffraction X-ray photoelectron spectroscopy and total reflection Fourier transform infrared spectroscopy characterized the surface films of different surface treated samples, and analyzed the structural composition and corrosion resistance mechanism of different films. Professional stainless steel plate, stainless steel coil, stainless steel belt, stainless steel pipe, high price, service, honest management! At present, there are few studies on the combination of citric acid passivation and silicon treatment of stainless steel. Therefore, silicon treatment and the combination of citric acid passivation and acid silicon system treatment, and discusses the corrosion resistance mechanism of different films on its surface, which can provide reference for the new direction of stainless steel surface treatment, It has certain practical guiding significance. The corrosion resistance and mechanism of chemical passivation, silicon treatment and composite treatment of martensitic stainless steel were studied in this paper. The comprehensive comparison of the research results shows that the corrosion resistance of stainless steel treated with different surface treatments is different. The corrosion resistance of the sample treated with silicon alone is better than that treated with traditional dichromate passivation. The corrosion resistance of the composite treated sample treated with citric acid passivation and acid silicon system is further enhanced than that treated with acid silicon system alone. The composite treatment of citric acid passivation and acid silicon system treatment has excellent corrosion resistance and environmental protection characteristics, and is expected to replace the traditional dichromate passivation treatment. According to the film weight test results, the surface silicon film weight of the composite treated sample after citric acid passivation and acid silicon system treatment is lower than that of the sample after acid silicon system treatment alone, indicating that the excellent corrosion resistance of the composite film not only depends on the surface silicon film, but also benefits from its double-layer film structure.
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