In the standard, it is DIN2391-1. The raw materials of hydraulic steel pipes undergo precision drawing, non oxidizing bright heat treatment (NBK state), non-destructive testing, high-pressure flushing and acid washing of the inner holes of the steel pipes, rust prevention oil treatment of the inner and outer walls of the steel pipes, and dust prevention treatment of the two end covers. The produced steel pipes have high precision and good smoothness, with no oxide layer on the inner and outer walls. The steel pipes can withstand the high pressure of liquid flow, and the steel pipes do not deform during cold bending. They can be expanded, flattened, and have no cracks. Mechanical properties can bend without deformation at any angle. Mainly used for preparing steel pipes in hydraulic system oil circuits, also known as hard piping in hydraulic systems, precision steel pipes for automobiles, with specifications generally ranging from outer diameter (D) to 76mm and wall thickness (S) to 0.5mm-6.0mm. The length is 6 meters (excluding custom-made), and the delivery status is NBK (normalized), GBK (annealed), BKS (stress relief annealed). The main materials used are ST35, ST37.4 (10 #), ST45 (20 #), ST55 (35 #), ST52 (16Mn), etc., which can meet customers' requirements for high precision, smoothness, tensile strength, and mechanical properties of steel pipes.
Introduction to hydraulic steel pipes based on European standard EN10305-4:2003: The precision hydraulic steel pipes produced are seamless pipes that have been precision cold drawn, and then undergo oxygen free tempering treatment to eliminate surface and internal stresses, followed by phosphating and rust prevention treatment. The product has high dimensional accuracy, good ductility, and is easy to process and bend into various required shapes without reducing or flattening the pipe cross-section; The surface precision of the pipe is high, and after oxygen free tempering treatment, the surface hardness is moderate and easy to connect with the sleeve. The inner hole and surface can be directly installed without acid washing and rust removal after phosphating and rust prevention treatment.
Honing tube: Cold rolled precision seamless steel pipe is a hydraulic steel pipe made from finished seamless steel pipe or seamless pipe blank, which is treated with acid washing, phosphating, and saponification, and then rolled by a cold rolling machine. The precision of hydraulic steel pipes is extremely high and can generally be controlled at 0. 02-0. Within the range of 05mm, the standard is GB3639-83, with an allowable deviation of 0.03mm for the inner diameter, an inner surface roughness of Ra 0.2-0.8 μ m, a hydraulic steel pipe straightness of 0.3-1.5mm/m, and a cylinder diameter specifically designed for oil steel.
The weight of seamless steel pipe is kg/m=(Od - Wt) * Wt * 0.02466, where Od is the outer diameter and Wt is the wall thickness: (outer diameter - wall thickness) * wall thickness * 0.02466 Kg/m.