Valve springs
In all the spring products than the valve spring on the material requirements are more stringent, especially high stress and shaped section of the valve spring on the material requirements are nearly harsh:
High strength: tensile strength 2000MPa.
Excellent surface quality: surface is not allowed to complete decarburization, half a deep decarburization depth of no more than 0.5% of the wire diameter, surface defect depth of no more than 40 microns, to meet the requirements of the steel wire in the process of machining, surface peeling and through two ways (through type and rotary eddy current flaw detection, defect parts automatic spray logo.
Ultra-purity: the inclusions of oxides and sulfides are up to grade 0, and the content of oxygen and nitrogen as well as copper, aluminum and titanium in the materials are required to be controlled. Therefore, the production of valve spring steel needs to be controlled from the source of smelting.
Good anti-relaxation performance: the valve spring is required to be in service for a long time at 120 ~ 150℃ with load attenuation less than 5%.
Strength uniformity: the strength of the same disk material difference is not more than 140MPa, shaped cross section materials such as the oval cross section of the curvature of different circles tangent point, elliptical cross section of the length and length of the axis have special requirements.
