The definition of Special-shaped seamless steel pipes
Special-shaped seamless steel pipes are a general term for cross-sectional shapes other than round pipes and play a vital role in urban construction.
Its quality directly affects the sturdiness and quality of residential buildings. Production standards include ASTM A53, ASTM A106, ASTM A179, ASTM A192, etc.
The key characteristics and features of special-shaped seamless steel pipes
1. Variety of Shapes: Common shapes include square, rectangular, oval, hexagonal, octagonal, D-shaped, and other custom geometric forms.
2. Seamless Construction: Like standard seamless pipes, these special-shaped pipes are manufactured without a weld seam, offering higher strength and uniformity throughout the structure.
3. Material Properties: These pipes can be made from various steel grades, including carbon steel, alloy steel, stainless steel, and other specialized steel types, each offering different mechanical and chemical properties.
4. Dimensional Accuracy: They are produced with high dimensional accuracy, ensuring consistent cross-sectional dimensions, which is crucial for applications requiring precise fitting and alignment.
5. Strength and Durability: Seamless construction and the inherent properties of the steel used give these pipes high strength and durability, making them suitable for heavy-duty applications.
Inspection methods for special-shaped seamless steel pipes
1. Inspection of geometric dimensions and shape of steel pipes
a. Steel pipe wall thickness inspection: micrometer, ultrasonic thickness gauge, no less than 8 points at both ends and recorded.
b. Check the outer diameter and ovality of steel pipes: calipers, vernier calipers, ring gauges, measure maximum and minimum points.
c. Steel pipe length measurement: steel tape measure, manual, automatic length measurement.
d. Check steel pipe bending: ruler, level (1m), feeler gauge, thin wire to measure bending per meter, full length bending.
e. Steel pipe end bevel and blunt edge inspection: square ruler, clamping plate
2. Steel pipe surface quality inspection
Manual visual inspection: lighting conditions, standards, experience, signs, steel pipe rotation. Non-destructive testing: ultrasonic testing UT, eddy current testing ET, magnetic particle MT and magnetic flux leakage testing, electromagnetic ultrasonic testing, penetrating testing.
Inferior special-shaped seamless steel pipes have the following characteristics
1. Is the surface smooth?
Due to the poor quality of raw materials and steel rolling equipment used, unprofessional technical methods, and low cost, special-shaped seamless steel pipes will suffer from surface folding, numbness, scarring, cracks, and easy scratches.
Generally, this situation can be discovered through visual inspection.
Therefore, it is recommended that consumers must treat these situations rationally. Don't buy low-quality square pipe just for the sake of cheapness. The strength and hardness of these special-shaped seamless steel pipes are not up to standard, which will affect their future use.
2. Whether the surface has metallic luster?
Some inferior special-shaped seamless steel pipes are made of adobe and have non-standard temperatures. Steel temperature is controlled by visual inspection.
In this way, the rolled steel will appear red or the color of pig iron. It does not have the metallic luster and performance of real special-shaped seamless steel pipes.
3. Are the dimensions and weight acceptable?
Generally, the size of inferior and special-shaped seamless steel pipes fluctuates greatly. In order to save raw materials, most of them are insufficient in weight.
