07Cr25Ni21 seamless stainless steel pipe, as a high-performance special steel, plays a crucial role in many industrial fields. In particular, its unique material properties and wide range of applications make it an indispensable material in numerous engineering projects.
Details of 07Cr25Ni21 Seamless Stainless Steel Pipe
1. Production methods for 07Cr25Ni21 seamless stainless steel pipe include: cold-rolled seamless steel pipe, cold-drawn seamless steel pipe, and delivery after heat treatment and rinsing.
2. Chemical composition of 07Cr25Ni21 seamless stainless steel pipe (%): Nickel: 19.00~22.00, Chromium: 24.00~26.00, Silicon ≤0.75, Manganese: ≤2.00, Carbon: 0.040~0.10, Sulfur: ≤0.015, Phosphorus: ≤0.030
First, the chemical composition and physical properties of 07Cr25Ni21 seamless stainless steel pipe.
According to its chemical composition, 07Cr25Ni21 seamless stainless steel pipe mainly contains approximately 25% chromium and 21% nickel, and may also contain small amounts of carbon, silicon, manganese, phosphorus, and sulfur. The high content of chromium and nickel gives this stainless steel excellent corrosion resistance and high-temperature strength. Chromium forms a dense oxide film on the surface of steel, effectively preventing corrosion from oxygen and other corrosive media, while nickel enhances the structural stability of the steel and improves its creep resistance at high temperatures.
In terms of physical properties, 07Cr25Ni21 seamless stainless steel pipe has high density, good thermal conductivity, and a low coefficient of linear expansion. Its density is approximately 8.0 g/cm³, meaning that for the same volume, it is heavier than some other stainless steel types, but this also results in better wear resistance. Good thermal conductivity makes this material perform excellently in heat exchange equipment, while the low coefficient of linear expansion ensures dimensional stability in high or low temperature environments.
Second, the corrosion resistance and weldability of 07Cr25Ni21 seamless stainless steel pipe.
07Cr25Ni21 seamless stainless steel pipe is renowned for its excellent corrosion resistance, especially in both oxidizing and reducing media. In chloride-containing environments, although its corrosion resistance is slightly inferior to some super stainless steels, it is sufficient for most conventional chemical media. Furthermore, this material exhibits good corrosion resistance to organic acids such as nitric acid and acetic acid, making it suitable for manufacturing chemical containers and pipelines.
Regarding weldability, 07Cr25Ni21 seamless stainless steel pipe belongs to austenitic stainless steel and has good weldability. However, due to its high nickel and chromium content, it is prone to hot cracking during welding, especially in the welding of thick-walled materials. Therefore, in practical operation, measures such as preheating, interpass temperature control, and slow cooling after welding are necessary to reduce crack formation. In addition, selecting appropriate welding materials is crucial to ensuring weld quality; it is generally recommended to use welding wire or electrodes with a composition similar to the base metal.
Thirdly, Application Areas of 07Cr25Ni21 Seamless Stainless Steel Pipe.
Due to its unique properties, 07Cr25Ni21 seamless stainless steel pipe is widely used in multiple fields:
1. Chemical Industry: Due to its excellent corrosion resistance, it is particularly suitable for manufacturing pipelines, reaction vessels, heat exchangers, and other components in chemical equipment.
2. Power Industry: In nuclear power plants and thermal power plants, 07Cr25Ni21 seamless stainless steel pipes are used in critical components such as high-temperature and high-pressure steam pipelines, condensers, and feedwater heaters.
3. Oil and Gas Industry: Due to its excellent corrosion resistance and high-temperature strength, it is suitable for pipelines handling corrosive media during oil and gas extraction and transportation.
4. Food Processing Industry: 07Cr25Ni21 seamless stainless steel pipes that meet food-grade standards can be used to manufacture conveying pipelines and storage tanks in food production equipment, ensuring food safety.
5. Environmental Protection and Water Treatment: In environmental protection projects such as wastewater treatment and seawater desalination, 07Cr25Ni21 seamless stainless steel pipes are highly favored due to their corrosion resistance.
Fourth, Production Process and Quality Control of 07Cr25Ni21 Seamless Stainless Steel Pipes.
The production of 07Cr25Ni21 seamless stainless steel pipes mainly involves the following steps: raw material preparation, heating and piercing, rolling and stretching, heat treatment, pickling and passivation, inspection and testing, and finished product packaging.
- Raw Material Preparation: High-quality 07Cr25Ni21 seamless stainless steel tube blanks are selected to ensure uniform chemical composition and absence of inclusions.
- Heating and Piercing: After heating the blank to a suitable temperature, it is pierced through a piercing mill to form a preliminary tube blank.
- Rolling and Extending: The pierced tube blank is rolled in multiple passes, gradually reducing the diameter and increasing the wall thickness of the 07Cr25Ni21 seamless stainless steel tube until the required size specifications are achieved.
- Heat Treatment: The rolled 07Cr25Ni21 seamless stainless steel tube undergoes solution treatment and aging treatment to eliminate internal stress and improve the uniformity of microstructure and performance stability.
- Pickling and Passivation: Pickling removes oxide scale and impurities from the surface of the 07Cr25Ni21 seamless stainless steel tube, followed by passivation treatment to enhance surface corrosion resistance.
- Inspection and Testing: The finished 07Cr25Ni21 seamless stainless steel tube undergoes visual inspection, dimensional measurement, mechanical property testing, and hydrostatic testing to ensure product quality meets standards.
- Finished Product Packaging: Qualified 07Cr25Ni21 seamless stainless steel pipes undergo rust-proofing treatment and are packaged using suitable packaging materials for transportation and storage.
Regarding quality control, in addition to the strict monitoring of the production process mentioned above, rigorous chemical composition analysis of raw materials is conducted, regular sampling inspections of finished products are carried out, and a comprehensive quality traceability system is established to ensure the traceability and quality stability of each batch of products.
In summary, 07Cr25Ni21 seamless stainless steel pipes, with their excellent performance, wide range of applications, and strict production quality control, have become an indispensable material in the industrial field. With continuous technological advancements and accelerated industrialization, the demand for 07Cr25Ni21 seamless stainless steel pipes will continue to grow, and its development prospects are promising.
Post time: Nov-25-2025