Quality Inspection Of Seamless Steel Pipe

Seamless steel pipe is one of the important products in OCTG products. It is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, automobile transmission shaft, bicycle frame and construction of steel scaffolding and so on. Comparing with the other steel pipe, seamless steel pipe has stronger anti-bending and torsional ability under the condition of the same cross section area. It is widely used in the national economy, and is entitled to the "industrial blood vessel". Therefore, the quality of seamless steel pipe has very demanding requirements.

Seamless steel pipe inspection generally include: inspection geometry, surface quality; test chemical composition, mechanical properties, process performance, high and low times of the organization; NDT inspection; some special performance inspection and weighing length measurement. Let’s look at some relatively important quality inspection together.

 

Seamless steel tube geometry inspection

• Seamless steel pipe wall thickness inspection    Micrometer is the main tool that is adopted. When you check, left hand holds the micrometer stand, with right hand rotation induced wheel, and the wire rod should be coincident with the diameter of the measuring point. Once found that the wall thickness is not qualified, it should be marked in time.
• Outside diameter, ellipse of seamless steel pipe inspection    Calipers, vernier caliper should be taken. The caliper should be perpendicular to the axis of the steel pipe in checking, measuring the maximum and the minimum point when the pipe rotated slowly. Founding the outer diameter of large or small, you should mark it in time.
• Seamless steel tube length inspection    The steel tape can be measured directly by metallic tape.
• Bending inspection of seamless steel tubes    With the tools of level, feeler and line.
• End profile inspection    At two ends of the steel tube should be cut into specified angle and remove burrs. The method of inspection adopts angle square and general use tube end groove clamp in the field.

Mechanical properties and process performance check of seamless steel tube

In order to verify the mechanical properties of seamless steel pipe to meet the requirements of the standard, the test sample of seamless steel pipe mechanical performance should be prepared carefully. Mechanical property test includes tensile strength, yield strength, elongation, impact energy and so on. Process performance test includes flattening test, flaring test, hydrostatic testing, curling trials, cold bend test, perforation test. These test items are based on different standards and different uses of seamless steel tubes.

Non-destructive testing of seamless steel pipe

Under the premise of not damaging the specimen, NDT refers to carry out inspection and testing to internal and surface structure, properties, status of specimen with physical or chemical methods, advanced technology and equipment. The development of non destructive testing technology has experienced three stages: Nondestructive detection, nondestructive testing and nondestructive evaluation.

Nondestructive detection is the name of the early stage, and the meaning is to detect and detect defects; Nondestructive testing is the name of the current stage, its meaning is not only to detect defects, but also to detect some other information, such as the structure, nature, status, etc.; And nondestructive evaluation (NDE) is one which is entered or is entering a new stage, it requires not only the defects are found, but also detection test pieces of the structure, properties, status, and access more comprehensive and more accurate, comprehensive information, such as defects associated with the shape, size, location, orientation, inclusions, tissue defect, residual stress force of information. It is necessary to combined with imaging technology, automation technology, and computer data analysis and processing technology, and mechanics of materials, and other fields of knowledge, and gives a comprehensive and accurate evaluation of the quality and performance of the test piece or product.