Title:
EVALUATION METHOD FOR METAL WIRE FOR SPRING
Document Type and Number:
Japanese Patent JP3178655
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain an evaluation method in which an irregularity in the free length of a metal wire after a spring working operation can be estimated and evaluated at the atage of a wire rod by a method wherein the irregularity is estimated on the basis of at least one out of the difference between the maximum value and the minimum value of residual stresses in a plurality of places in the metal wire and the index of a specific expression.
SOLUTION: A condition such as a heat-treatment condition or the like is changed, and samples whose residual stress is different are manufactured. Then, the residual stress in the length direction of the respective wire rods is measured. By this measurement, data on a total of 12 places, i.e., four places (obtained by dividing an outer circumferential line into four equal parts) in the circumferential direction on the surface of every wire rod and three places in the axial direction, are obtained. Then, on the basis of the respective data, an index 1 and an index 2 are found. σmax-σmin refers to the index 1, where σmax represents the maximum value of the residual stress, and σmin represents the minimum value of the residual value. ρ[[Σσn2-{(Σσn)2/n}]/n]1/2 refers to the index 2, where σ represents the residual stress. It is already known that the index 1 and the index 2 are in a correlation between the free length of a spring and a moving average. Consequently, before the spring is worked, the residual stress of every wire rod is measured, the difference or the standard deviation between the maximum value and the minimum value of the measured data is computed, and an irregularity in the free length of a metal wire can be estimated.
Inventors:
Yukihiro Oishi
Go Yoshioka
Go Yoshioka
Application Number:
JP1745797A
Publication Date:
June 25, 2001
Filing Date:
January 13, 1997
Export Citation:
Assignee:
Sumitomo Electric Industries, Ltd.
International Classes:
G01L1/00; G01N3/00; (IPC1-7): G01L1/00
Domestic Patent References:
| JP8278208A | ||||
| JP9125137A | ||||
| JP1287222A | ||||
| JP6376730A | ||||
| JP7136933A | ||||
| JP1108305U |
Attorney, Agent or Firm:
Hidemi Aoki (1 outside)
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