Quality management method, quality management gauge, and quality management gauge set for screw component

摘要

A management torque value smaller than a specified torque value is defined beforehand, and a screw ring-form, plug management gauge (11), which is capable of being screwed with plug (3), is prepared. Gauge (11) is provided with marked lines (14a, 14b) showing upper and lower limit positions of tolerance of the orientation of ground electrode (33) when plug (3) and gauge (11) have been screwed with each other. When plug (3) and gauge (11) have been screwed with each other and tightened at the management torque value, suitability of the phase position in the rotational direction is evaluated and managed by whether or not ground electrode (33) of plug (3) is in a range of marked lines (14a, 14b) showing the upper and lower limit positions of the tolerance. With this, it becomes possible to conduct a phase management with consideration of the crushing deformation characteristics of the gasket even with a torque lower than the specified tightening torque.

主权项

1. A method for conducting quality control of a screw component, the method being a method for previously managing a phase position in a rotational direction when a screw component having a sealing portion that demonstrates a sealing function by plastic deformation is tightened to a corresponding screw portion with a specified torque value,
wherein a management torque value lower than the specified torque value is previously determined, wherein a gauge having a screw portion that is capable of being screwed on the screw component is prepared, wherein there are previously each determined upper and lower limit positions of a tolerance of the phase position in the rotational direction in the screw component, when the screw component and the gauge are screwed together and tightened with the management torque value, wherein it is judged as a non-defective product in case that a reference portion at the phase position in the rotational direction in the screw component is within a range of the upper and lower limit positions of the tolerance, and it is judged as a defective product in case that the reference portion at the phase position in the rotational direction is not within a range of the upper and lower limit positions of the tolerance, when the screw component and the gauge are screwed together and tightened with the management torque value is evaluated.