Precision seamless pipe is an important form and type of seamless pipe, which has a wide range of applications in various construction projects, building construction, and decoration. The phenomenon of fracture of precision seamless pipe is always found in production and major sales, which is due to many links not being done well in production, as well as insufficient ingredients and incorrect proportions of chemical elements.
1. Small longitudinal crack
The small longitudinal cracks on the surface of precision seamless pipes have a length of less than 200mm, a width of less than 3mm, and a depth of less than 0.3mm.
2. Peak shaped crack
The cracks all occurred at a distance of 5-60mm from the edge of the precision seamless tube, and the macroscopic direction was perpendicular to the rolling direction, forming a "mountain peak" shape.
3. Edge crack
The crack mainly occurs at a distance of 20-80mm from the edge of the precision seamless tube, with the morphology of multiple parallel longitudinal cracks of different sizes. The pattern is that the thicker and wider the specification of the precision seamless tube, the more severe this type of defect.
4. Inclusion and scarring
The inclusions and scars are distributed in a regular pattern, and the phenomenon is obvious after finishing operations such as edge flame peeling crack inspection or casting scratch flame cleaning.
For the fiber structure and crystal defects such as dislocations and vacancies in steel, annealing or normalizing heat treatment methods are generally adopted to eliminate them. The purpose of annealing is to refine grains, eliminate structural defects, reduce hardness, improve plasticity, and facilitate cold processing. Annealing equipment is indispensable in the production of cold drawn precision seamless tubes. Therefore, developing appropriate annealing processes is a necessary condition to ensure that the microstructure of precision seamless tubes is qualified and that products do not have fracture defects. If manufacturers reduce annealing processes in order to unilaterally lower production costs, it will inevitably have a negative impact on product quality.
YB/T5035-1993 (Seamless steel pipe for automotive half shaft sleeve pipe). Mainly used for producing carbon structural steel and alloy structural steel hot-rolled seamless steel pipes for automobile half axle sleeves and drive axle housing shaft pipes. Its representative materials are 45, 45Mn2, 40Cr, 20CrNi3A, etc.
Seamless steel pipe is formed as a whole, directly perforated with round steel, without any welds on the surface, and has a wide range of applications. So, what are the uses of seamless steel pipe? Let's learn about it together.
1、 What are the uses of seamless steel pipes
Seamless steel pipes have a wide range of applications, including structures, fluid transportation, low and medium pressure boilers, high-pressure boilers, fertilizer equipment, petroleum cracking, geological drilling, diamond core drilling, petroleum drilling, ships, automotive half shaft sleeves, diesel engines, and more. The use of seamless steel pipes can avoid problems such as leakage, ensure the effectiveness of use, and improve material utilization.
