CYLINDRICAL METAL CASE WITH BOTTOM AND ITS MANUFACTURING METHOD, AND ULTRASONIC OSCILLATOR USING CYLINDRICAL METAL CASE WITH BOTTOM, AND ULTRASONIC FLOWMETER HAVING ULTRASONIC OSCILLATOR

摘要

PROBLEM TO BE SOLVED: To provide a highly precise and reliable ultrasonic oscillator and an ultrasonic flowmeter, by realizing a case having flat case top face with no fear of stress corrosion crack with respect to the case used for an ultrasonic oscillator and made by cut or press and integral moulding. SOLUTION: The case was formed by cut or press and integral molding is subjected to heat treatment within 60 minutes at heat treatment temperature of 150-300°C. At this time, temperature rising speed is made 5°C/min or smaller and cooling rate is made 1.0°C/min or smaller. Then, the case having a case top face of degree of planarity of 5μm or smaller with no fear of stress corrosion crack can be realized. COPYRIGHT: (C)2009,JPO&INPIT