The specific specifications and parameters of GB 75KG heavy rail are as follows:
Specification
Rail height: 192mm
Head width: 75mm
Bottom width: 150mm
Waist thickness: 20mm
Theoretical weight: 74.414kg/m
Length: The standard length is usually 25m, and other lengths can be produced according to user requirements, but there is generally a certain length tolerance range.
Material and chemical composition: Common materials include U75V, etc. Taking U75V as an example, its chemical composition requires a carbon (C) content of 0.71% -0.80%, silicon (Si) content of 0.50% -0.80%, manganese (Mn) content of 0.65% -1.05%, phosphorus (P) content not exceeding 0.035%, sulfur (S) content not exceeding 0.035%, and vanadium (V) content of 0.04% -0.12%.
Sectional characteristics:
The distance between the center of gravity and the rail base is about 80.5mm. This parameter is very important for the force analysis and stability calculation of the track, as it determines the distribution of train loads on the track section.
In terms of moment of inertia, the moment of inertia for the horizontal axis is about 5220cm ⁴, and the moment of inertia for the vertical axis is about 902cm ⁴. The moment of inertia reflects the ability of the rail to resist bending deformation. The larger the value, the less likely the rail is to undergo bending deformation when subjected to train loads, which helps to ensure the smoothness and stability of the track.
The cross-sectional coefficient is approximately 544cm ³ for the horizontal axis and 120cm ³ for the vertical axis. The section coefficient is an important indicator for measuring the load-bearing capacity of steel rails, which is closely related to the bending moment and stress borne by the rails.
Curvature radius of rail head: The rail head usually has a certain curvature radius to meet the contact requirements between the wheel and the rail. The curvature radius of the GB 75KG heavy rail head is generally designed as a specific value. For example, in some standards, the inner curvature radius of the rail head may be around 30mm, and the outer curvature radius may be around 80mm. This curvature design helps to reduce the contact stress between the wheel and the rail, reduce wear and fatigue damage, and improve the service life of the track.
Dimensional tolerance:
The allowable deviation of rail height is ± 0.5mm, which is to ensure that different rails can maintain consistent height after laying, in order to provide smooth driving conditions.
The allowable deviation for head width and bottom width is ± 0.5mm, ensuring the dimensional accuracy of the rail head and bottom to ensure good contact with the wheels and stability of the track.
The allowable deviation of waist thickness is ± 0.3mm, and the precision control of waist thickness is crucial for the strength and bearing capacity of the steel rail.
Straightness: Steel rails should have good straightness, with a curvature of no more than 0.5mm per meter and a curvature of no more than 4mm throughout the entire length. The strict requirement for straightness is to ensure the smoothness of train travel and reduce the impact and vibration between the wheel and rail.