Square tubes are a type of tubular shape with a square cross-section. Many different materials can be used to form square tube structures. They are versatile and used for various purposes, in numerous applications. Most square tubes are made of steel, and they are commonly used for structural, decorative, and construction purposes.

Hollow square tubes, also known as square steel tubes with equal sides, are made by rolling steel strips through a specific process. Typically, steel strips are unpacked, leveled, curled, and welded into round tubes, which are then rolled into square tubes and cut to the desired length. They are usually packaged with 50 tubes per bundle.

Square tubes come in seamless and welded varieties. Seamless square tubes are formed by extruding seamless round tubes.

1. Performance Index Analysis of Square Pipe - Plasticity

Plasticity refers to the ability of metallic materials to undergo plastic deformation under load without being damaged.

2. Performance Index Analysis of Square Pipe - Hardness

Hardness is a measure of the degree of softness or hardness of metal materials. Currently, the indentation hardness test method is commonly used in production to determine hardness. This method involves pressing a geometrically shaped indenter into the surface of the metal material being tested under a certain load, and the hardness value is determined based on the degree of indentation.

Common methods include Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC), and Vickers hardness (HV).

Section 3: Performance Index Analysis of Square Tubes - Fatigue

The discussed strength, plasticity, and hardness are all mechanical property indicators of metals under static load. In reality, many machine parts operate under cyclic loads, where fatigue in the parts occurs under these conditions.

4. Performance Index Analysis of Square Tubes - Impact Toughness

A load that acts on machinery at a high speed is called an impact load. The ability of metal to resist damage under impact loads is known as impact toughness.

5. Performance Index Analysis of Square Pipe - Strength

Strength refers to the ability of metal materials to resist damage under static loads (excessive plastic deformation or fracture). Since the application of loads can take the form of tension, compression, bending, and shearing, strength is categorized into tensile strength, compressive strength, bending strength, and shearing strength, among others. There is often a certain connection between different strengths, and in practice, tensile strength is generally used as the basic strength indicator.