Material Selection

　　According to the use of the environment:

　　General environment:such as indoor dry environment or ordinary civil construction,201 stainless steel tube can be used,its price is relatively low,but corrosion resistance and strength is relatively poor.

　　General corrosion-resistant environment:such as most of the outdoor environment,food processing workshop,general industrial plant,etc.,304 stainless steel tube is a common choice,with good corrosion resistance,heat resistance and processing performance.

　　Strong corrosive environment:such as seaside,chemical,ocean engineering and other high chloride ion content or strong acid and alkali and other corrosive media environment,it is recommended to use 316 or 316L stainless steel tube,its corrosion resistance is stronger than 304 type,especially in the resistance to chloride corrosion outstanding performance.

　　Consider special requirements:

　　High strength requirements:If the project have high strength requirements for the pipe,such as for supporting structures or high-pressure pipelines,etc.,you can choose martensitic type stainless steel pipe,such as 410,420 and other models,with high strength,high hardness,high abrasion resistance,but the corrosion resistance is relatively weak.

　　High toughness and weldability requirements:for projects that require bending,welding and other processing,ferritic type stainless steel tubes,such as 430,409 and other models,with good toughness and weldability,suitable for the manufacture of decorative,architectural and other uses of the pipe.

　　Size specification

　　Pipe diameter selection:

　　Flow demand:according to the flow demand of the fluid in the project to determine the diameter of the pipe,the larger the flow,the larger the required pipe diameter to ensure the smooth flow of the fluid in the pipe.

　　Pressure level:different diameters of the pipeline have different pressure capacities,in the selection of the pipeline diameter,should consider the pressure level required in the project,to ensure that the selected diameter of the pipeline can withstand the corresponding pressure.

　　Installation space:the installation space of the pipeline is also one of the factors to be considered when selecting the diameter,in the limited space,may need to choose a smaller diameter pipe to adapt to the installation conditions.

　　Wall thickness selection:

　　Pressure-bearing capacity:the wall thickness of the pipe is directly proportional to its pressure-bearing capacity,in the need to withstand higher pressure occasions,should choose a larger wall thickness of the pipe to ensure safety.

　　Corrosion resistance:wall thickness will also affect the corrosion resistance of the pipeline,in a more corrosive environment,thicker walls can better resist the erosion of corrosive media to extend the service life of the pipeline.

　　Economy:the greater the wall thickness,the higher the material cost of the pipe,therefore,when choosing the wall thickness,you need to meet the project requirements under the premise of considering the economic factors to avoid excessive waste.

　　Production process

　　Seamless pipe and welded pipe:

　　Stainless steel seamless pipe:using the process of extrusion and stretching,the pipe wall is uniform,high strength,suitable for demanding pressure occasions,widely used in chemical industry,ships and other fields,but the price is relatively high.

　　Stainless steel welded pipe:it is welded stainless steel plate forming,relatively low cost,widely applicable,generally used for water supply,drainage and other conventional uses,but need to pay attention to the quality of the weld.

　　Manufacturer technology:choose manufacturers with advanced production processes and mature technology,and the quality of their stainless steel pipes is more guaranteed.For example,you can find out whether the calendering technology of the manufacturer is over the top,to avoid the situation of stainless steel pipe thickness is not the same.

　　Appearance quality

　　Surface inspection:the surface of a good stainless steel pipe should be bright and smooth,uniform thickness,no roughness,no obvious scratches,pits,cracks or other defects.It can be checked by visual observation or by touching the surface of the pipe with the hand.

　　Weld quality:for welded pipe,check the flatness and strength of the weld,the weld should be straight,neat,no misalignment,depression,porosity,slag entrapment or other defects,and there is no obvious colour change in the weld and the weld periphery.

　　Testing and Certification

　　Chemical composition analysis:to ensure that the content of various elements in the pipe meets the standard requirements,such as chromium,nickel,molybdenum and other major alloying elements of the content is up to standard to ensure the performance of stainless steel pipe.

　　Mechanical performance test:detect the strength,hardness,toughness and other mechanical performance indicators of the pipe to ensure that it can meet the requirements of the project.

　　Corrosion resistance test:simulate the corrosion resistance of the pipe in different environments,such as salt spray test,intergranular corrosion test,etc.,to verify its corrosion resistance in the actual use of the environment.

　　Non-destructive testing:such as ultrasonic testing,ray testing,etc.,which can detect defects inside and on the surface of the pipeline to ensure the quality and safety of the pipeline.

　　Brand and Merchant

　　Brand reputation:choosing a famous brand can ensure the quality of the product and reduce the trouble of maintenance in the later stage.Famous brands usually have more perfect production management system and quality control system.

　　After-sales service:good after-sales service can provide protection for the project,if you encounter problems during installation or use,you can get timely help,such as product returns,maintenance,technical advice and other services.