Stainless steel pipe: high-quality pipe for corrosion-resistant transportation and structural support

Stainless steel pipe is a tubular material made from stainless steel containing ≥10.5% chromium (a core corrosion-resistant element) and optionally alloyed with nickel, molybdenum, and is seamlessly rolled or welded. Its core value lies in its "compatibility of corrosion resistance with tubular functionality"—it inherits the rust-resistant and hygienic advantages of stainless steel while also possessing the pipe's "fluid transport and structural support" properties. It is widely used in industries such as food, medicine, chemicals, construction, and municipal engineering, where corrosion resistance and safety are paramount. It represents a high-end tubular material distinct from carbon steel pipe. Based on its core attributes, it can be further categorized into seamless and welded stainless steel pipes, depending on the production process. Seamless pipes are formed by hot-rolling, piercing, and cold drawing/rolling. They have no welds and offer high pressure resistance (withstanding 10-50 MPa at room temperature), making them suitable for high-pressure fluid transportation (such as chemical high-pressure pipelines). Welded pipes are formed from stainless steel sheets/coils, rolled and welded together. These include straight seam welded pipes (with welds running along the axis, suitable for medium and low-pressure applications) and spiral welded pipes (with spiral welds, offering excellent crack resistance and suitable for large-diameter transportation). Their cost is 20%-30% lower than seamless pipes. Based on material composition, these pipes are categorized into austenitic stainless steel pipes (such as 304 and 316, which are non-magnetic, have good plasticity, and are highly corrosion-resistant, accounting for over 70% of market share); ferritic stainless steel pipes (such as 430, which contains chromium but no nickel, is magnetic, and is low-cost, primarily used for decorative structures); and martensitic stainless steel pipes (such as 410, which can be quenched and hardened, has high strength but poor corrosion resistance, and is suitable for mechanical load-bearing pipes). ​

Its core features focus on "corrosion resistance + functional adaptability": First, its corrosion resistance far exceeds that of carbon steel pipes. The passivation film formed by chromium resists corrosion from humid air and freshwater. Because 316 stainless steel pipes contain molybdenum, they can also withstand seawater and strong acids and alkalis (such as chemical wastewater and medical disinfectants). Carbon steel pipes require galvanizing or painting for rust prevention and are prone to corrosion and leakage in acidic and alkaline environments. Second, its hygienic properties are outstanding. Austenitic stainless steel pipes have a smooth surface and are free of impurities, meeting food-grade (GB 4806) and medical-grade standards. They are suitable for transporting drinking water, food slurries, and pharmaceutical solutions, which carbon steel pipes cannot meet. Third, it offers a balanced balance between pressure bearing capacity and lifespan. Seamless stainless steel pipes have a pressure bearing capacity close to that of alloy steel pipes and a service life of 20-50 years (compared to the 5-10 years of carbon steel pipes). Although the unit price is 3-6 times that of carbon steel pipes, they require less frequent replacement and maintenance, resulting in better long-term cost-effectiveness. Fourth, they are flexible to install and lighter than carbon steel pipes. 10%-15% (for the same specifications), and it can be welded and flanged, making it suitable for complex installation scenarios.

Application scenarios cover high-demand tubing applications: In the food and medical industry, 304 seamless stainless steel pipe is used for drinking water transportation and milk/juice production line piping, while 316L seamless pipe is used for medical infusion tubing and surgical instrument flushing pipes. In the chemical industry, 316 seamless pipe is used for acid and alkali solution transportation and reactor connection pipes, and spiral welded pipe is used for large-diameter chemical wastewater treatment pipes. In the construction and municipal engineering sector, 304 welded pipe is used for indoor water supply and drainage pipes and heating pipes (scale resistance), while 430 ferritic pipe is used for decorative structures such as railings and handrails. In the marine engineering sector, 316L seamless pipe is used for seawater cooling pipes and offshore platform oil pipelines (seawater corrosion resistance). In addition, the automotive industry uses 410 martensitic stainless steel pipe for exhaust pipes (high-temperature corrosion resistance), and the new energy sector uses 304 seamless pipe for lithium battery electrolyte pipelines. ​

Three key points to consider when using this product: First, material selection and compatibility. For high-pressure/acid-base applications, prioritize 316 seamless pipe; for food and medical applications, choose 304/316L seamless pipe; and for decorative structures, choose 430 welded pipe. Avoid over-selection of materials. Second, regarding processing and installation, welding requires the use of specialized stainless steel welding wire (e.g., ER308L for 304 pipe, ER316L for 316 pipe). After welding, pickling and passivation are required (to repair the passivation film and prevent intergranular corrosion). Direct contact with carbon steel pipe is prohibited (to avoid galvanic corrosion; insulating gaskets are required). Third, regarding maintenance and protection, daily clean the surface with a neutral detergent (e.g., dishwashing liquid). Avoid using steel wool or strong acid cleaners (e.g., hydrochloric acid) to prevent scratching or damaging the passivation film. For pipes installed outdoors or in humid environments, regular inspection of joint seals is required to prevent leakage due to seal aging. Salt and dust on the surface should also be removed to prevent localized corrosion.