How to judge the performance of seamless steel pipe?

Evaluating the performance of seamless steel pipes involves examining several key properties, including yield point, tensile strength, hardness index, reduction of area, and elongation after fracture. Understanding these properties is essential for ensuring the pipes meet the required standards for their intended applications.

Yield Point
For metal materials that exhibit a yield phenomenon, the yield point is the stress at which a sample continues to elongate without an increase in force during the stretching process. If the force drops, the upper and lower yield points are distinguished. The unit of yield point is N/mm² (MPa).

Tensile Strength
Tensile strength (σ) is calculated by dividing the maximum force (Fb) the sample withstands during stretching by the original cross-sectional area (So) of the sample. This property, expressed in N/mm² (MPa), indicates the ability of metal materials to resist damage under tension.

Hardness Index
Hardness measures a metal's resistance to surface indentation by hard objects. Depending on the test method and application scope, hardness can be categorized into Brinell hardness, Rockwell hardness, Vickers hardness, Shore hardness, microhardness, and high-temperature hardness.

Reduction of Area
In a tensile test, the reduction of area is the percentage decrease in the cross-sectional area at the narrowest point of the sample after it breaks, compared to the original cross-sectional area.

Elongation after Fracture
Elongation after fracture is determined in a tensile test as the percentage increase in the gauge length of the sample after it breaks, relative to the original gauge length.

Understanding these performance metrics is crucial for ensuring the seamless steel pipes are suitable for their intended applications and meet the necessary mechanical property standards.