Hot stress and metal quality volume changes Shi of organization stress is greater than steel of anti-break strength; work appearance of original defects (as appearance micro-crack or classified marks) or steel internal defects (as clip slag, and serious of non-metallic clip debris, and white, and shrinkage residual,) quenching Shi formed stress concentrated; serious of appearance off carbon and carbide partial analysis of; parts quenching Hou tempered lack or is not timely tempered; front processes caused of cold rushed stress had large, and forging folding, and deep of turning knife, and oil Groove sharp edges,. In short, NSK bearing on internal stress in quenching process due to the formation of crack quench cracks. This crack causes are due to hardening heating temperature is too high or cooling too quickly. Cause of quenching crack may be one or more of the above factors, stress and quenching crack of the formation of the main causes. Quenching crack deep, slender, fracture, straight and cutting plane no oxidation. Straight crack on bearing rings tend to be vertical or circular cracks; NSK bearings steel ball shape on s-shaped, t-shaped or ring-shaped. Characteristics of quenching crack is cracked on both sides without removal, significant differences and forging crack crack and material.
NSK bearing heat treatment
Thermal stress and organizational stress, when in heat treatment of bearing parts. This within stress can mutual overlay or part offset, complex changeable of because it can as heating temperature, and heating speed, and cooling way, and cooling speed, and parts shape and size of changes and changes, so heat treatment deformation is inevitably of awareness and master it changes law can make NSK bearing parts of deformation (as rings of oval, and size rose large,) placed can controlled of range, conducive to production of for. During thermal treatment of mechanical collision also cause deformation of parts, but this variant is could be reduced by improving operations and avoid