ASME-UT工艺

应通过探头在探测面的移动，使焊缝全体积均受超声束扫查。探头的扫查路径应至少重叠探头横向宽度的10%

The volume shall be examined by moving the search unit over the examination surface so as to scan the entire examination volume .Each pass of the search unit shall overlap a minimum of 10% of the transducer (piezo-electric element) dimension perpendicular to the direction of the scan. 3.2探头移动速度 3.2 Speed of Search Unit Movements 探伤时，探头移动速度应不大于150mm/s。

The speed of search unit movement for examination shall not exceed 6 in./sec (150mm/sec.) 3.3记录水平

3.3 Recording Level 凡波高超过50% DAC基准线而未予返修的讯号均应记录在案。

All reflections from uncorrected areas having responses that exceed 50% of reference level shall be recorded. This record shall locate each area, the response level, the dimensions, the depth below the surface, and the classification. 4.超声仪、探头和参数

4. ULTRASONIC INSTRUMENT, SEARCH UNIT AND PARAMETERS 4.1 超声仪

4.1 Ultrasonic Instrument 应使用下列脉冲反射式超声仪：

A pulse-echo type of ultrasonic instrument shall be used. The following instruments are recommended in examination.

Instrument Type Manufactured by 仪器型号 制造单位

CTS-26 Shantou, China CTS 26 汕头超声仪器厂

NJBST

Co.,Ltd. QCD-013 Rev.:0 Page:4 of 12 Title: ULTRASONIC EXAMINATION PROCEDURE

Search Unit type Beam Angle(β) Frequency Manufactured 4.2 探头

by 直探头直径应为14~25mm.斜探头应根据被检工件厚度适当选用(参照下表)：

2.5P 450 2.5MHz Shantou, China 探头折射角与被检壁厚关系：

8x12 4.3 频率

2.5P 560 2.5MHz Shantou, China 通常应频率2.5MHz，对薄板，可采用5MHz 。

8x12 4.4 屏高线性

2.5P 630 2.5MHz Shantou, China 超声应提供±5%满屏高的垂直线性(在20%至80%校正屏高的范围内)。 8x12 屏高线性的测评方法按ASME 第V卷A篇第5章附录Ⅰ，应在每一周期开始(或每3个月，取两者中时短者)测评一次。

2.5P 680 2.5MHz Shantou, China 4.5 波幅控制线性

8x12 为能测量示波屏上超出垂直线性范围的信号，超声仪应有在有用范围内可精确到标称波幅比±20%的波幅控制器。评定波幅控制线性的方法，见ASME第V卷第5章附录Ⅱ。此评定应在每一延长使用周期开始时进行(或每3个月进行一次，取两者中较短的时间)。

4.6 设备校验

对探伤设备应使用校正试块于每次检查开始和结束时进行性能校验，当探伤人员更换时，或怀疑有故障时，也要校验。校验时发现探伤设备性能不佳时，所有产品均应重新检查(自设备上次有效校验算起)。

Wall Thickness (mm) Beam Angle (β) K Value (tgβ) 5. 校正

8月25日 720-630 3.0-2.0 5.1 基本校正试块

>25-46 680-560 2.5-1.5

>46 630-450 2.0-1.0

壁厚(mm) 折射角(β) K (tgβ) 8月

值 25

日 720-630 3.0-2.0

>25-46 680-560 2.5-1.5

>46 630-450 2.0-1.0

探头 折射角(β) 频率 造

单位 2.5P

8x12

450

2.5MHz

汕头超声仪器汕头超声仪器汕头超声仪器汕头超声仪器

厂 2.5P 8x12 560 2.5MHz 厂 2.5P 8x12 630 2.5MHz 厂 2.5P 8x12 680 2.5MHz 厂

制

4.2 Search Unit

For straight beam, the diameter of transducer shall be 14mm-25mm. For angle beam, an angle shall be selected as appropriate for the configuration being examined. The following search units are recommended to be used in examination:

The

range

of

angle

is

recommended

as

following:

4.3

Frequency

Generally, the frequency of 2.5MHz shall be used. For the thinner plate, 5MHz may be used. 4.4

Screen

Height

linearity The ultrasonic instrument shall provide linear vertical presentation within±5% of the full screen height for 20% to 80 of the calibrated screen height (base line to maximum calibrated screen point(s)). The procedure for evaluating screen height linearity is provided in Appendix Ⅰof ASME Code Sect. V Sub. A Article 5 and shall be performed at the beginning of each period of extended use (or every 3 months, whichever is less). 4.5 Amplitude Control Linearity The ultrasonic instrument shall utilize an amplitude control accurate over its useful range to ±20% of the nominal amplitude ratio, to allow measurement of indications beyond the linear range of the vertical display on the screen. The procedure for evaluating amplitude control linearity is given in ASME Sect V. Art .5. Appendix Ⅱand shall be performed at the beginning of each period of extended use(or every 3 months, whichever is less). 4.6 Checking and Calibration of Equipment

The proper functioning of the examination equipment shall be checked and the equipment shall be calibrated by the use of the calibration standard at the beginning and end of each examination., when examination personnel are changed, and at any time that malfunctioning is suspected as a minimum. If during any check it is determined that the testing equipment is not functioning properly, all of the product that has been tested since the last valid equipment calibration shall be reexamined.

5.

CALIBRATION 5.1

Basic

Calibration

Block

Configuration