DIN 17175 is a standard for seamless steel pipes for elevated temperatures and was developed for use in boiler and pressure vessel construction. It is one of the most important German standards for seamless steel pipes and specifies the qualifty criteria and the mechanical and chemical properties of the pipes in addition to the dimensional requirements.
The standard covers pipes of sizes up to and including 250 millimetre in nominal bore size and is divided into different groups and categories according to the application.
Group 1 – Seamless steel pipes for general purposes
Group 2 – Steel pipes with improved atmospheric corrosion resistant
Group 3 – Additional requirements for pipes for use in boilers, pipelines and other pressure systems
Group 4 – Steel pipes for the transport of liquids and gases
This standard is further divided in terms of composition and properties required in different grades. The grade number refers to the requirements of the alloy and the chemical and mechanical properties.
The most commonly used alloy material for DIN 17175 pipes is carbon steel (st37.4). Other materials include, amongst others, phosphorus and sulfur alloyed steels.
The requirements for pipes for different applications are defined in terms of chemical and mechanical properties which include the strength, impact strength, thermal conductivity, tensile strength and sensitivity to corrosion. The requirements also include the fracture toughness, grain size and total carbon content of the material used.
The dimension requirements for DIN 17175 pipes are in terms of maximum and minimum wall thickness, length, diameter, pipe length tolerance and bend radius. The tolerances specified in this standard apply to the manufacturing of pipes in lengths up to 3m and with a diameter of up to 250mm. The bend radius is established in terms of the geometric size of the bend and is also dependent on the material and wall thickness.
The quality control requirements specified in the standard include the acceptance of samples prior to production, control of the finished product in terms of chemical and mechanical properties and non-destructive testing. Non destructive testing of the pipes includes visual inspection, magnetic particle inspection, ultrasonic testing and hydrostatic pressure testing.
The specifications of DIN 17175 are applicable to all types of seamless steel pipes for use in applications which are exposed to elevated temperatures. It is suitable for a wide range of materials, sizes and applications and provides a basis for the high quality and long-term service life of pipes used in high temperature applications. The standard provides specifications and guidelines for the manufacture and quality assurance of stainless steel pipes and helps to ensure that these pipes are safe and reliable.
