Seamless pipe(cs seamless pipe) is a long steel pipe with a hollow section and no joints around it. The compressive strength of the seamless pipe refers to the limit of the seamless pipe when it is produced, that is, the in-situ stress that resists the micro-analyzed plastic deformation. External forces exceeding this limit will permanently invalidate the part beyond repair.
The external factors that affect the compressive strength of seamless pipes are temperature, strain rate, and in-situ stress.
1) With the decrease of temperature and the increase of strain rate, the compressive strength of seamless pipe increases, especially in places where body-centered cubic meter metal materials are sensitive to temperature and strain rate, which is easy to cause ultra-low temperature embrittlement of steel ;
2) The hazards of in-situ stress conditions are also critical. Although the compressive strength is an essential index value reflecting the essential characteristics of the raw material, the in-situ stress situation is different, and the compressive strength value is also different.
The intrinsic factors that affect the compressive strength of seamless pipes are: fusion bond, mechanism, structure, and molecular nature. For example, comparing the compressive strength of metal materials with porcelain and fiber materials, it can be seen that the harm of fusion bonds is global.
Calculation formula of compressive strength of seamless pipe:
1) Knowing the outer diameter and wall thickness of the seamless pipe, the calculation method of the pressure it can withstand (the tensile strength of different materials of the steel pipe is different)
Pressure = (wall thickness * 2 * tensile strength of steel pipe material) / (outer diameter * coefficient)
2) Calculation method of wall thickness for known seamless pipe outer diameter and pressure
Wall thickness = (pressure * outer diameter * coefficient) / (2 * tensile strength of steel pipe material)
3) Representation method of steel pipe pressure coefficient:
Pressure P<7Mpa, coefficient S=8; 7
Tips: the deviation of the seamless pipe size will also have a certain impact on the compressive strength.
